Hepatic betaine-homocysteine methyltransferase activity in the chicken is influenced by dietary intake of sulfur amino acids, choline and betaine.

PubMed

Emmert, J L; Garrow, T A; Baker, D H

1996-08-01

There is much interest in the metabolism of homocysteine, because elevated plasma homocysteine [hyperhomocyst(e)inemia] is an independent risk factor for the development of cardiovascular disease. Four chick assays were conducted to determine the effects of varying dietary sulfur amino acids, choline and betaine on the activity of hepatic betaine-homocysteine methyltransferase (BHMT), an enzyme likely to be important in modulating plasma homocysteine. In Experiment 1, chicks were fed a purified crystalline amino acid diet containing adequate sulfur amino acids and choline. Excess dietary methionine, or the combination of excess cystine with choline or betaine, caused a small increase (P < 0.05) in BHMT activity. In Experiment 2, use of a methionine-deficient purified diet resulted in a threefold increase (P < 0.05) in BHMT activity, and addition of choline or betaine further increased (P < 0.05) BHMT activity. In Experiment 3, use of a methionine-deficient corn-peanut meal diet increased BHMT (P < 0.05) relative to that of chicks supplemented with adequate methionine, and addition of surfeit choline to the methionine-deficient basal diet caused a further increase (P < 0.05). In Experiment 4, addition of both surfeit choline and surfeit betaine to the methionine-deficient corn-peanut meal diet caused an increase (P < 0.05) in BHMT activity relative to that observed in chicks fed the methionine-deficient basal diet. These assays show that large increases in BHMT activity can be produced under methionine-deficient conditions, especially in the presence of excess choline or betaine.

Optical resolution of phenylthiohydantoin-amino acids by capillary electrophoresis and identification of the phenylthiohydantoin-D-amino acid residue of [D-Ala2]-methionine enkephalin.

PubMed

Kurosu, Y; Murayama, K; Shindo, N; Shisa, Y; Ishioka, N

1996-11-01

This is an initial report to propose a protein sequence analysis system with DL differentiation using capillary electrophoresis (CE). This system consists of a protein sequencer and a CE system. After fractionation of phenyl-thiohydantoin (PTH)-amino acids using a protein sequencer, optical resolution for each PTH-amino acid is performed by CE using some chiral selectors such as digitonin, beta-escin and others. As a model peptide, [D-Ala2]-methionine enkephalin (L-Tyr-D-Ala-Gly-L-Phe-L-Met), was used and the sequence with DL differentiation was determined, with the exception of the fourth amino acid, L-Phe, using our proposed system.

Factors influencing methionine toxicity in young bobwhite quail

USGS Publications Warehouse

Serafin, J.A.

1981-01-01

Young Bobwhite quail (Colinus virginianus) were fed low and adequate protein purified diets with and without excess methionine to evaluate factors affecting methionine toxicity. Growth of quail fed an adequate protein (27%) diet, without supplemental glycine, was depressed by 1.75% and 2.25% excess methionine. Supplemental glycine (.3%) alleviated growth depression caused by 2.25% excess methionine. Quail fed 1.75% and 2.25% excess methionine developed signs of toxicity characterized by weakness, a lowered, outstretched neck when moving, and ataxia. In addition, quail would fall on their sides when disturbed and spin with their heads retracted. These conditions were transient in nature. Growth of quail fed a low protein (18.9%) diet was depressed by 1% and 1.5% excess methionine and DL-homocystine. Quail fed 1% and 1.5% excess methionine in this diet also developed signs of toxicity, the incidence of which was greater and the duration longer than occurred with quail fed adequate protein. Supplementing a low protein (20.15%) diet with .3% or .6% glycine or threonine or a combination of these amino acids did not alleviate growth depression caused by 1.5% excess methionine; however, 2% and 3% supplemental glycine were somewhat effective. Supplements of glycine (2%, 3%) and threonine (1%) completely reversed growth depression from 1% excess methionine but did not influence growth of controls, indicating that both amino acids counteract methionine toxicity. Both glycine and threonine alone improved growth by about the same extent in diets with 1% or 1.5% excess methionine; however, these amino acids alleviated less than 30% of the growth depression resulting from 1.5% excess methionine. The effectiveness of glycine in alleviating methionine toxicity in a low protein diet was decreased, and hemoglobin levels were depressed with 1.5% excess methionine compared to less amounts.

Antioxidant activity of amino acids in soybean oil at frying temperature: Structural effects and synergism with tocopherols.

PubMed

Hwang, Hong-Sik; Winkler-Moser, Jill K

2017-04-15

The purpose of this study was to evaluate amino acids as natural antioxidants for frying. Twenty amino acids were added to soybean oil heated to 180°C, and the effects of amino acid structure on the antioxidant activity were investigated. Amino acids containing a thiol, a thioether, or an extra amine group such as arginine, cysteine, lysine, methionine, and tryptophan had the strongest antioxidant activities. At 5.5mM, these amino acids had stronger antioxidant activities than 0.02% (1.1mM) tert-butylhydroquinone (TBHQ). A functional group such as an amide, carboxylic acid, imidazole, or phenol appeared to negatively affect amino acid antioxidant activity. Synergism between amino acids and tocopherols was demonstrated, and we found that this synergistic interaction may be mostly responsible for the antioxidant activity that was observed. In a frying study with potato cubes, 5.5mM l-methionine had significantly stronger antioxidant activity than 0.02% TBHQ. Published by Elsevier Ltd.

Dry-extrusion of asian carp to supplement natural methionine in organic poultry production

USDA-ARS?s Scientific Manuscript database

Methionine, a sulfur containing amino acid, is essential for healthy poultry production. Synthetic methionine is commonly used as a supplement in conventional poultry. However, for organic poultry, a natural, cost effective source of methionine that can replace synthetic methionine is unavailable. I...

The effect of antioxidants on quantitative changes of lysine and methionine in linoleic acid emulsions at different pH conditions.

PubMed

Hęś, Marzanna; Gliszczyńska-Świgło, Anna; Gramza-Michałowska, Anna

2017-01-01

Plants are an important source of phenolic compounds. The antioxidant capacities of green tea, thyme and rosemary extracts that contain these compounds have been reported earlier. However, there is a lack of accessible information about their activity against lipid oxidation in emulsions and inhibit the interaction of lipid oxidation products with amino acids. Therefore, the influence of green tea, thyme and rosemary extracts and BHT (butylated hydroxytoluene) on quantitative changes in lysine and methionine in linoleic acid emulsions at a pH of isoelectric point and a pH lower than the isoelectric point of amino acids was investigated. Total phenolic contents in plant extracts were determined spectrophotometrically by using Folin-Ciocalteu's reagent, and individual phenols by using HPLC. The level of oxidation of emulsion was determined using the measurement of peroxides and TBARS (thiobarbituric acid reactive substances). Methionine and lysine in the system were reacted with sodium nitroprusside and trinitrobenzenesulphonic acid respectively, and the absorbance of the complexes was measured. Extract of green tea had the highest total polyphenol content. The system containing antioxidants and amino acid protected linoleic acid more efficiently than by the addition of antioxidants only. Lysine and methionine losses in samples without the addition of antioxidants were lower in their isoelectric points than below these points. Antioxidants decrease the loss of amino acids. The protective properties of antioxidants towards methionine were higher in a pH of isoelectric point whereas towards lysine in pH below this point. Green tea, thyme and rosemary extracts exhibit antioxidant activity in linoleic acid emulsions. Moreover, they can be utilized to inhibit quantitative changes in amino acids in lipid emulsions. However, the antioxidant efficiency of these extracts seems to depend on pH conditions. Further investigations should be carried out to clarify this issue.

Effects of rumen-protected methionine on plasma amino acid concentrations during a period of weight loss for late gestating beef heifers

USDA-ARS?s Scientific Manuscript database

This study determined changes in plasma amino acid concentration in late-gestating (beginning 58 ± 1.02 d prior to calving), primiparous, winter-grazing range heifers receiving wheat middling based supplement without (CON) or with rumen-protected methionine (MET) to provide 15 g DL- MET each day. Pl...

The Role of Rumen-Protected Methionine on Amino Acid Metabolism in Late Gestation Beef Heifers in the Northern Great Plains

USDA-ARS?s Scientific Manuscript database

This study evaluated changes in plasma amino acids in late-gestating (beginning 58 ± 1.02 d prior to calving), primiparous, winter-grazing range heifers receiving a wheat middling based supplement without (CON) or with rumen-protected methionine (MET). Plasma was collected on d -2 and d 0 (start of ...

[Biosynthesis of enniatin by washed cells of Fusarium sambucinum].

PubMed

Minasian, A E; Chermenskĭ, D N; Bezborodov, A M

1979-01-01

Biosynthesis of the depsipeptide membrane ionophore--enniatin B by the washed mycelium Fusarium sambucinum Fuck 52 377 was studied. Metabolic precursors of enniatin B, alpha-ketovaleric acid, 14C-L-valine, and 14CH3-methionine, were added to the system after starvation. The amino acid content in the metabolic pool increased 1.5 times after addition of alpha-ketovaleric acid, 2.2 times after that of valine, and 2.5 times after addition of methionine. 14C-L-valine and 14CH3-methionine were incorporated into the molecule of enniatin B. Valine methylation in the molecule occurred at the level of synthesized depsipeptide. Amino acids of the metabolic pool performed the regulatory function in the synthesis.

Synthesis of the sulfur amino acids: cysteine and methionine.

PubMed

Wirtz, Markus; Droux, Michel

2005-12-01

This review will assess new features reported for the molecular and biochemical aspects of cysteine and methionine biosynthesis in Arabidopsis thaliana with regards to early published data from other taxa including crop plants and bacteria (Escherichia coli as a model). By contrast to bacteria and fungi, plant cells present a complex organization, in which the sulfur network takes place in multiple sites. Particularly, the impact of sulfur amino-acid biosynthesis compartmentalization will be addressed in respect to localization of sulfur reduction. To this end, the review will focus on regulation of sulfate reduction by synthesis of cysteine through the cysteine synthase complex and the synthesis of methionine and its derivatives. Finally, regulatory aspects of sulfur amino-acid biosynthesis will be explored with regards to interlacing processes such as photosynthesis, carbon and nitrogen assimilation.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover.

PubMed

Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A; Sands, David C; Reboud, Xavier

2017-01-01

Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro , rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management.

The why and how of amino acid analytics in cancer diagnostics and therapy.

PubMed

Manig, Friederike; Kuhne, Konstantin; von Neubeck, Cläre; Schwarzenbolz, Uwe; Yu, Zhanru; Kessler, Benedikt M; Pietzsch, Jens; Kunz-Schughart, Leoni A

2017-01-20

Pathological alterations in cell functions are frequently accompanied by metabolic reprogramming including modifications in amino acid metabolism. Amino acid detection is thus integral to the diagnosis of many hereditary metabolic diseases. The development of malignant diseases as metabolic disorders comes along with a complex dysregulation of genetic and epigenetic factors affecting metabolic enzymes. Cancer cells might transiently or permanently become auxotrophic for non-essential or semi-essential amino acids such as asparagine or arginine. Also, transformed cells are often more susceptible to local shortage of essential amino acids such as methionine than normal tissues. This offers new points of attacking unique metabolic features in cancer cells. To better understand these processes, highly sensitive methods for amino acid detection and quantification are required. Our review summarizes the main methodologies for amino acid detection with a particular focus on applications in biomedicine and cancer, provides a historical overview of the methodological pre-requisites in amino acid analytics. We compare classical and modern approaches such as the combination of gas chromatography and liquid chromatography with mass spectrometry (GC-MS/LC-MS). The latter is increasingly applied in clinical routine. We therefore illustrate an LC-MS workflow for analyzing arginine and methionine as well as their precursors and analogs in biological material. Pitfalls during protocol development are discussed, but LC-MS emerges as a reliable and sensitive tool for the detection of amino acids in biological matrices. Quantification is challenging, but of particular interest in cancer research as targeting arginine and methionine turnover in cancer cells represent novel treatment strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

Investigation of Amino Acids As Herbicides for Control of Orobanche minor Parasitism in Red Clover

PubMed Central

Fernández-Aparicio, Mónica; Bernard, Alexandre; Falchetto, Laurent; Marget, Pascal; Chauvel, Bruno; Steinberg, Christian; Morris, Cindy E.; Gibot-Leclerc, Stephanie; Boari, Angela; Vurro, Maurizio; Bohan, David A.; Sands, David C.; Reboud, Xavier

2017-01-01

Certain amino acids induce inhibitory effects in plant growth due to feedback inhibition of metabolic pathways. The inhibition patterns depend on plant species and the plant developmental stage. Those amino acids with inhibitory action on specific weeds could be utilized as herbicides, however, their use for weed control has not been put into practice. Orobanche minor is a weed that parasitizes red clover. O. minor germination is stimulated by clover root exudates. The subsequent seedling is an obligated parasite that must attach quickly to the clover root to withdraw its nutrients. Early development of O. minor is vulnerable to amino acid inhibition and therefore, a series of in vitro, rhizotron, and field experiments were conducted to investigate the potential of amino acids to inhibit O. minor parasitism. In in vitro experiments it was found that among a collection of 20 protein amino acids, lysine, methionine and tryptophan strongly interfere with O. minor early development. Field research confirmed their inhibitory effect but revealed that methionine was more effective than lysine and tryptophan, and that two successive methionine applications at 308 and 543 growing degree days inhibited O. minor emergence in red clover up to 67%. We investigated additional effects with potential to influence the practical use of amino acids against broomrape weeds, whether the herbicidal effect may be reversible by other amino acids exuded by host plants or may be amplified by inducing host resistance barriers against O. minor penetration. This paper suggests that amino acids may have the potential to be integrated into biorational programs of broomrape management. PMID:28588599

The oxidation of amino acids by ferrate(V). A pre-mix pulse radiolysis study.

PubMed

Rush, J D; Bielski, B H

1995-06-01

The forms of ferrate(V) which are derived from the one-electron reduction of potassium ferrate (K2FeO4) by ethanol radicals react with representative amino acids (glycine, methionine, phenylalanine and serine) at rates that are greater than 10(5)M-1s-1 near pH 10. The predominant interaction in the alkaline pH range is between the protonated ferrate(V) species, HFeO4(2-), and the amino acid anion. Fe(V) + amino acid-->Fe(III) + NH3 + alpha-keto acid The rate-determining process is the two electron reduction of ferrate(V) to iron(III) with oxidation and subsequent deamination of the amino acid. The reaction appears to involve an entry of the amino acid into the inner coordination sphere of ferrate(V). In all cases, ferrate(V) exhibits preferred attack on the amino group in contrast to the OH radical which attacks the thioether site of methionine and the phenyl ring of phenylalanine.

Methionine peptide formation under primordial earth conditions.

PubMed

Li, Feng; Fitz, Daniel; Fraser, Donald G; Rode, Bernd M

2008-01-01

According to recent research on the origin of life it seems more and more likely that amino acids and peptides were among the first biomolecules formed on earth and that a peptide/protein world was thus a key starting point in evolution towards life. Salt-induced Peptide Formation (SIPF) has repeatedly been shown to be the most universal and plausible peptide-forming reaction currently known under prebiotic conditions and forms peptides from amino acids with the help of copper ions and sodium chloride. In this paper we present experimental results for salt-induced peptide formation from methionine. This is the first time that a sulphur-containing amino acid was investigated in this reaction. The possible catalytic effects of glycine and L-histidine in this reaction were also investigated and a possible distinction between the L- and D-forms of methionine was studied as well.

Methionine biosynthesis is essential for infection in the rice blast fungus Magnaporthe oryzae.

PubMed

Saint-Macary, Marie Emmanuelle; Barbisan, Crystel; Gagey, Marie Josèphe; Frelin, Océane; Beffa, Roland; Lebrun, Marc Henri; Droux, Michel

2015-01-01

Methionine is a sulfur amino acid standing at the crossroads of several biosynthetic pathways. In fungi, the last step of methionine biosynthesis is catalyzed by a cobalamine-independent methionine synthase (Met6, EC 2.1.1.14). In the present work, we studied the role of Met6 in the infection process of the rice blast fungus, Magnaporthe oryzae. To this end MET6 null mutants were obtained by targeted gene replacement. On minimum medium, MET6 null mutants were auxotrophic for methionine. Even when grown in presence of excess methionine, these mutants displayed developmental defects, such as reduced mycelium pigmentation, aerial hypha formation and sporulation. They also displayed characteristic metabolic signatures such as increased levels of cysteine, cystathionine, homocysteine, S-adenosylmethionine, S-adenosylhomocysteine while methionine and glutathione levels remained unchanged. These metabolic perturbations were associated with the over-expression of MgCBS1 involved in the reversed transsulfuration pathway that metabolizes homocysteine into cysteine and MgSAM1 and MgSAHH1 involved in the methyl cycle. This suggests a physiological adaptation of M. oryzae to metabolic defects induced by the loss of Met6, in particular an increase in homocysteine levels. Pathogenicity assays showed that MET6 null mutants were non-pathogenic on both barley and rice leaves. These mutants were defective in appressorium-mediated penetration and invasive infectious growth. These pathogenicity defects were rescued by addition of exogenous methionine and S-methylmethionine. These results show that M. oryzae cannot assimilate sufficient methionine from plant tissues and must synthesize this amino acid de novo to fulfill its sulfur amino acid requirement during infection.

Dry-extrusion of Asian Carp to supplement natural methionine for organic poultry production

USDA-ARS?s Scientific Manuscript database

Methionine, a sulfur containing amino acid, is essential for healthy poultry production. Synthetic methionine is commonly used as a supplement in conventional poultry. However, for organic poultry in the United States, a natural, cost effective source of methionine that can replace synthetic methion...

Response of rainbow trout to source and level of supplemental dietary methionine

USGS Publications Warehouse

Poston, H.A.

1986-01-01

1. Methionine and total sulfur amino acid (TSAA) requirements of rainbow trout (Salmo gairdneri) were investigated by feeding graded isosulfurous levels of l- and dl-methionine, l-cystine, and the free acid and calcium forms of methionine hydroxy analog (MHA).2. Added cystine did not promote growth, survival or prevent cataracts.3. l-methionine produced fastest growth, followed by dl-methionine, CaMHA and free acid MHA.4. Trout fed CaMHA gained 85.7 and 92.3% as much as those fed l-methionine and dl-methionine.5. Within each experiment, the level of L-methionine isomer that prevented cataracts was constant (1.86 g/100g protein in experiment (1), 1.45 in experiment (2) and was lower than for maximum growth (2.89 and 2.15 g) regardless of methionine source.

PubMed Central

Carbonneau, Roch; Demers, Jean-Marie

1965-01-01

The object of this experiment was to study the influence of essential amino acids on the growth, fatty infiltration of liver and cholesterol level of the serum in ducklings. A 11 per cent protein basal diet, deficient in many essential amino acids, given to ducklings, resulted in poor growth, fatty infiltration of liver and high cholesterol level of the serum. In our experimental design, three amino acids, lysine, methionine and threonine were promoting growth whereas lysine and threonine were preventing fatty infiltration of liver but methionine failed to do so. Rather than a deficiency in lysine alone, simultaneous deficiencies in valine, arginine and lysine resulted in better growth for ducklings. This protective effect of deficiency in valine and arginine together with one in lysine was not effective against fatty infiltration of liver. The cholesterolemia found for the ducklings given basal diet or diets with deficiency in many essential amino acids was higher than that found for the ducklings given diets without essential amino acids deficiency. PMID:4220644

Tobacco seeds expressing feedback-insensitive cystathionine gamma-synthase exhibit elevated content of methionine and altered primary metabolic profile

PubMed Central

2013-01-01

Background The essential sulfur-containing amino acid methionine plays a vital role in plant metabolism and human nutrition. In this study, we aimed to elucidate the regulatory role of the first committed enzyme in the methionine biosynthesis pathway, cystathionine γ-synthase (CGS), on methionine accumulation in tobacco seeds. We also studied the effect of this manipulation on the seed’s metabolism. Results Two forms of Arabidopsis CGS (AtCGS) were expressed under the control of the seeds-specific promoter of legumin B4: feedback-sensitive F-AtCGS (LF seeds), and feedback-insensitive T-AtCGS (LT seeds). Unexpectedly, the soluble content of methionine was reduced significantly in both sets of transgenic seeds. Amino acids analysis and feeding experiments indicated that although the level of methionine was reduced, the flux through its synthesis had increased. As a result, the level of protein-incorporated methionine had increased significantly in LT seeds by up to 60%, but this was not observed in LF seeds, whose methionine content is tightly regulated. This increase was accompanied by a higher content of other protein-incorporated amino acids, which led to 27% protein content in the seeds although this was statistically insignificantly. In addition, the levels of reducing sugars (representing starch) were slightly but significantly reduced, while that of oil was insignificantly reduced. To assess the impact of the high expression level of T-AtCGS in seeds on other primary metabolites, metabolic profiling using GC-MS was performed. This revealed significant alterations to the primary seed metabolism manifested by a significant increase in eight annotated metabolites (mostly sugars and their oxidized derivatives), while the levels of 12 other metabolites were reduced significantly in LT compared to wild-type seeds. Conclusion Expression of T-AtCGS leads to an increase in the level of total Met, higher contents of total amino acids, and significant changes in the levels of 20 annotated metabolites. The high level of oxidized metabolites, the two stress-associated amino acids, proline and serine, and low level of glutathione suggest oxidative stress that occurs during LT seed development. This study provides information on the metabolic consequence of increased CGS activity in seeds and how it affects the seed’s nutritional quality. PMID:24314105

Toxicity of nickel and silver to Nostoc muscorum: interaction with ascorbic acid, glutathione, and sulfur-containing amino acids

DOE Office of Scientific and Technical Information (OSTI.GOV)

Rai, L.C.; Raizada, M.

1987-08-01

Exposure of Nostoc muscorum to different concentrations of Ni and Ag brought about reduction in growth, carbon fixation, heterocyst production, and nitrogenase activity and increase in the loss of ions (K+, Na+). In an attempt to ameliorate the toxicity of test metals by ascorbic acid, glutathione, and sulfur-containing amino acids (L-cysteine and L-methionine), it was found that the level of protection by ascorbic acid and glutathione was more for Ag than Ni. However, metal-induced inhibition of growth and carbon fixation was equally ameliorated by methionine. But the level of protection by cysteine was quite different, i.e., 27% for Ni andmore » 22% for Ag. Protection of metal toxicity in N. muscorum by amino acids lends further support to self-detoxifying ability of cyanobacteria because they are known to synthesize all essential amino acids.« less

Effects of squat exercise and branched-chain amino acid supplementation on plasma free amino acid concentrations in young women.

PubMed

Shimomura, Yoshiharu; Kobayashi, Hisamine; Mawatari, Kazunori; Akita, Keiichi; Inaguma, Asami; Watanabe, Satoko; Bajotto, Gustavo; Sato, Juichi

2009-06-01

The present study was conducted to examine alterations in plasma free amino acid concentrations induced by squat exercise and branched-chain amino acid (BCAA) supplementation in young, untrained female subjects. In the morning on the exercise session day, participants ingested drinks containing either BCAA (isoleucine:leucine:valine=1:2.3:1.2) or dextrin (placebo) at 0.1 g/kg body weight 15 min before a squat exercise session, which consisted of 7 sets of 20 squats, with 3 min intervals between sets. In the placebo trial, plasma BCAA concentrations were decreased subsequent to exercise, whereas they were significantly increased in the BCAA trial until 2 h after exercise. Marked changes in other free amino acids in response to squat exercise and BCAA supplementation were observed. In particular, plasma concentrations of methionine and aromatic amino acids were temporarily decreased in the BCAA trial, being significantly lower than those in the placebo trial. These results suggest that BCAA intake before exercise affects methionine and aromatic amino acid metabolism.

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics.

PubMed

Price, Morgan N; Zane, Grant M; Kuehl, Jennifer V; Melnyk, Ryan A; Wall, Judy D; Deutschbauer, Adam M; Arkin, Adam P

2018-01-01

For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine) by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics

DOE Office of Scientific and Technical Information (OSTI.GOV)

Price, Morgan N.; Zane, Grant M.; Kuehl, Jennifer V.

For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. Here, we studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fillmore » 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine) by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.« less

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics

DOE PAGES

Price, Morgan N.; Zane, Grant M.; Kuehl, Jennifer V.; ...

2018-01-11

For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. Here, we studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fillmore » 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine) by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes.« less

Filling gaps in bacterial amino acid biosynthesis pathways with high-throughput genetics

PubMed Central

Kuehl, Jennifer V.; Melnyk, Ryan A.; Deutschbauer, Adam M.; Arkin, Adam P.

2018-01-01

For many bacteria with sequenced genomes, we do not understand how they synthesize some amino acids. This makes it challenging to reconstruct their metabolism, and has led to speculation that bacteria might be cross-feeding amino acids. We studied heterotrophic bacteria from 10 different genera that grow without added amino acids even though an automated tool predicts that the bacteria have gaps in their amino acid synthesis pathways. Across these bacteria, there were 11 gaps in their amino acid biosynthesis pathways that we could not fill using current knowledge. Using genome-wide mutant fitness data, we identified novel enzymes that fill 9 of the 11 gaps and hence explain the biosynthesis of methionine, threonine, serine, or histidine by bacteria from six genera. We also found that the sulfate-reducing bacterium Desulfovibrio vulgaris synthesizes homocysteine (which is a precursor to methionine) by using DUF39, NIL/ferredoxin, and COG2122 proteins, and that homoserine is not an intermediate in this pathway. Our results suggest that most free-living bacteria can likely make all 20 amino acids and illustrate how high-throughput genetics can uncover previously-unknown amino acid biosynthesis genes. PMID:29324779

Methionine Biosynthesis is Essential for Infection in the Rice Blast Fungus Magnaporthe oryzae

PubMed Central

Gagey, Marie Josèphe; Frelin, Océane; Beffa, Roland; Lebrun, Marc Henri; Droux, Michel

2015-01-01

Methionine is a sulfur amino acid standing at the crossroads of several biosynthetic pathways. In fungi, the last step of methionine biosynthesis is catalyzed by a cobalamine-independent methionine synthase (Met6, EC 2.1.1.14). In the present work, we studied the role of Met6 in the infection process of the rice blast fungus, Magnaporthe oryzae. To this end MET6 null mutants were obtained by targeted gene replacement. On minimum medium, MET6 null mutants were auxotrophic for methionine. Even when grown in presence of excess methionine, these mutants displayed developmental defects, such as reduced mycelium pigmentation, aerial hypha formation and sporulation. They also displayed characteristic metabolic signatures such as increased levels of cysteine, cystathionine, homocysteine, S-adenosylmethionine, S-adenosylhomocysteine while methionine and glutathione levels remained unchanged. These metabolic perturbations were associated with the over-expression of MgCBS1 involved in the reversed transsulfuration pathway that metabolizes homocysteine into cysteine and MgSAM1 and MgSAHH1 involved in the methyl cycle. This suggests a physiological adaptation of M. oryzae to metabolic defects induced by the loss of Met6, in particular an increase in homocysteine levels. Pathogenicity assays showed that MET6 null mutants were non-pathogenic on both barley and rice leaves. These mutants were defective in appressorium-mediated penetration and invasive infectious growth. These pathogenicity defects were rescued by addition of exogenous methionine and S-methylmethionine. These results show that M. oryzae cannot assimilate sufficient methionine from plant tissues and must synthesize this amino acid de novo to fulfill its sulfur amino acid requirement during infection. PMID:25856162

Sulphur-containing Amino Acids: Protective Role Against Free Radicals and Heavy Metals.

PubMed

Colovic, Mirjana B; Vasic, Vesna M; Djuric, Dragan M; Krstic, Danijela Z

2018-01-30

Sulphur is an abundant element in biological systems, which plays an important role in processes essential for life as a constituent of proteins, vitamins and other crucial biomolecules. The major source of sulphur for humans is plants being able to use inorganic sulphur in the purpose of sulphur-containing amino acids synthesis. Sulphur-containing amino acids include methionine, cysteine, homocysteine, and taurine. Methionine and cysteine are classified as proteinogenic, canonic amino acids incorporated in protein structure. Sulphur amino acids are involved in the synthesis of intracellular antioxidants such as glutathione and N-acetyl cysteine. Moreover, naturally occurring sulphur-containing ligands are effective and safe detoxifying agents, often used in order to prevent toxic metal ions effects and their accumulation in human body. Literature search for peer-reviewed articles was performed using PubMed and Scopus databases, and utilizing appropriate keywords. This review is focused on sulphur-containing amino acids - methionine, cysteine, taurine, and their derivatives - glutathione and N-acetylcysteine, and their defense effects as antioxidant agents against free radicals. Additionally, the protective effects of sulphur-containing ligands against the toxic effects of heavy and transition metal ions, and their reactivation role towards the enzyme inhibition are described. Sulphur-containing amino acids represent a powerful part of cell antioxidant system. Thus, they are essential in the maintenance of normal cellular functions and health. In addition to their worthy antioxidant action, sulphur-containing amino acids may offer a chelating site for heavy metals. Accordingly, they may be supplemented during chelating therapy, providing beneficial effects in eliminating toxic metals. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Sulfur amino acid metabolism in doxorubicin-resistant breast cancer cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Ryu, Chang Seon; Kwak, Hui Chan; Lee, Kye Sook

2011-08-15

Although methionine dependency is a phenotypic characteristic of tumor cells, it remains to be determined whether changes in sulfur amino acid metabolism occur in cancer cells resistant to chemotherapeutic medications. We compared expression/activity of sulfur amino acid metabolizing enzymes and cellular levels of sulfur amino acids and their metabolites between normal MCF-7 cells and doxorubicin-resistant MCF-7 (MCF-7/Adr) cells. The S-adenosylmethionine/S-adenosylhomocysteine ratio, an index of transmethylation potential, in MCF-7/Adr cells decreased to {approx} 10% relative to that in MCF-7 cells, which may have resulted from down-regulation of S-adenosylhomocysteine hydrolase. Expression of homocysteine-clearing enzymes, such as cystathionine beta-synthase, methionine synthase/methylene tetrahydrofolate reductase,more » and betaine homocysteine methyltransferase, was up-regulated in MCF-7/Adr cells, suggesting that acquiring doxorubicin resistance attenuated methionine-dependence and activated transsulfuration from methionine to cysteine. Homocysteine was similar, which is associated with a balance between the increased expressions of homocysteine-clearing enzymes and decreased extracellular homocysteine. Despite an elevation in cysteine, cellular GSH decreased in MCF-7/Adr cells, which was attributed to over-efflux of GSH into the medium and down-regulation of the GSH synthesis enzyme. Consequently, MCF-7/Adr cells were more sensitive to the oxidative stress induced by bleomycin and menadione than MCF-7 cells. In conclusion, our results suggest that regulating sulfur amino acid metabolism may be a possible therapeutic target for chemoresistant cancer cells. These results warrant further investigations to determine the role of sulfur amino acid metabolism in acquiring anticancer drug resistance in cancer cells using chemical and biological regulators involved in sulfur amino acid metabolism. - Research Highlights: > MCF-7/Adr cells showed decreases in cellular GSH, which were attributed to increase efflux of GSH. > MCF-7/Adr was more sensitive to oxidative stress induced by bleomycin and menadione. > Hcy-clearing enzymes involved in were up-regulated in MCF-7/Adr cells. > Doxorubicin-resistance attenuated Met-dependence and activated transsulfuration. > Regulating sulfur amino acid metabolism may be a possible therapeutic target.« less

Photooxidation of Methionine

ERIC Educational Resources Information Center

Lewis, Catherine; Scouten, William H.

1976-01-01

Describes an experiment in which the photooxidation of methionine using free methylene blue as the sensitizer is applied to the isolated amino acid or to the methionyl residues of a complex polypeptide. (MLH)

Ecological genomics of Boechera stricta: identification of a QTL controlling the allocation of methionine- vs branched-chain amino acid-derived glucosinolates and levels of insect herbivory.

PubMed

Schranz, M E; Manzaneda, A J; Windsor, A J; Clauss, M J; Mitchell-Olds, T

2009-05-01

In the Brassicaceae, glucosinolates influence the feeding, reproduction and development of many insect herbivores. Glucosinolate production and effects on herbivore feeding have been extensively studied in the model species, Arabidopsis thaliana and Brassica crops, both of which constitutively produce leaf glucosinolates mostly derived from the amino acid, methionine. Much less is known about the regulation or role in defense of glucosinolates derived from other aliphatic amino acids, such as the branched-chain amino acids (BCAA), valine and isoleucine. We have identified a glucosinolate polymorphism in Boechera stricta controlling the allocation to BCAA- vs methionine-derived glucosinolates in both leaves and seeds. B. stricta is a perennial species that grows in mostly undisturbed habitats of western North America. We have measured glucosinolate profiles and concentrations in 192 F(2) lines that have earlier been used for genetic map construction. We also performed herbivory assays on six F(3) replicates per F(2) line using the generalist lepidopteran, Trichoplusia ni. Quantitative trait locus (QTL) analysis identified a single locus controlling both glucosinolate profile and levels of herbivory, the branched chain-methionine allocation or BCMA QTL. We have delimited this QTL to a small genomic region with a 1.0 LOD confidence interval just 1.9 cm wide, which, in A. thaliana, contains approximately 100 genes. We also found that methionine-derived glucosinolates provided significantly greater defense than the BCAA-derived glucosinolates against feeding by this generalist insect herbivore. The future positional cloning of this locus will allow for testing various adaptive explanations.

Accumulation, selection and covariation of amino acids in sieve tube sap of tansy (Tanacetum vulgare) and castor bean (Ricinus communis): evidence for the function of a basic amino acid transporter and the absence of a γ-amino butyric acid transporter.

PubMed

Bauer, Susanne N; Nowak, Heike; Keller, Frank; Kallarackal, Jose; Hajirezaei, Mohamad-Reza; Komor, Ewald

2014-09-01

Sieve tube sap was obtained from Tanacetum by aphid stylectomy and from Ricinus after apical bud decapitation. The amino acids in sieve tube sap were analyzed and compared with those from leaves. Arginine and lysine accumulated in the sieve tube sap of Tanacetum more than 10-fold compared to the leaf extracts and they were, together with asparagine and serine, preferably selected into the sieve tube sap, whereas glycine, methionine/tryptophan and γ-amino butyric acid were partially or completely excluded. The two basic amino acids also showed a close covariation in sieve tube sap. The acidic amino acids also grouped together, but antagonistic to the other amino acids. The accumulation ratios between sieve tube sap and leaf extracts were smaller in Ricinus than in Tanacetum. Arginine, histidine, lysine and glutamine were enriched and preferentially loaded into the phloem, together with isoleucine and valine. In contrast, glycine and methionine/tryptophan were partially and γ-amino butyric acid almost completely excluded from sieve tube sap. The covariation analysis grouped arginine together with several neutral amino acids. The acidic amino acids were loaded under competition with neutral amino acids. It is concluded from comparison with the substrate specificities of already characterized plant amino acid transporters, that an AtCAT1-like transporter functions in phloem loading of basic amino acids, whereas a transporter like AtGAT1 is absent in phloem. Although Tanacetum and Ricinus have different minor vein architecture, their phloem loading specificities for amino acids are relatively similar. © 2014 Scandinavian Plant Physiology Society.

Amino acid metabolism in the human fetus at term: leucine, valine, and methionine kinetics.

PubMed

van den Akker, Chris H P; Schierbeek, Henk; Minderman, Gardi; Vermes, Andras; Schoonderwaldt, Ernst M; Duvekot, Johannes J; Steegers, Eric A P; van Goudoever, Johannes B

2011-12-01

Human fetal metabolism is largely unexplored. Understanding how a healthy fetus achieves its fast growth rates could eventually play a pivotal role in improving future nutritional strategies for premature infants. To quantify specific fetal amino acid kinetics, eight healthy pregnant women received before elective cesarean section at term, continuous stable isotope infusions of the essential amino acids [1-13C,15N]leucine, [U-13C5]valine, and [1-13C]methionine. Umbilical blood was collected after birth and analyzed for enrichments and concentrations using mass spectrometry techniques. Fetuses showed considerable leucine, valine, and methionine uptake and high turnover rates. α-Ketoisocaproate, but not α-ketoisovalerate (the leucine and valine ketoacids, respectively), was transported at net rate from the fetus to the placenta. Especially, leucine and valine data suggested high oxidation rates, up to half of net uptake. This was supported by relatively low α-ketoisocaproate reamination rates to leucine. Our data suggest high protein breakdown and synthesis rates, comparable with, or even slightly higher than in premature infants. The relatively large uptakes of total leucine and valine carbon also suggest high fetal oxidation rates of these essential branched chain amino acids.

Nutritional value of protein hydrolysis products (oligopeptides and free amino acids) as a consequence of absorption and metabolism kinetics

NASA Technical Reports Server (NTRS)

Rerat, A.

1995-01-01

When pigs were submitted to duodenal infusion of solutions containing a large percentage of small peptides (PEP) or free amino acids with the same pattern (AAL) amino acids appear in the portal blood more rapidly and more uniformly after infusion of PEP then after infusion of AAL, with the notable exception of methionine for which the opposite was true. These differences were lowered when a carbohydrate (maltose dextrin) was present in the solution, but nevertheless remained significant for the first hour after the infusion. The long-term (8-hour) uptake of free amino acids into the liver and the peripheral tissues differed in profile according to the nature of the duodenal infusion. Peripheral uptake was appreciably less well balanced after infusion of free amino acids (deficiency of threonine and phenylalanine) than after infusion of small peptides (deficiency of methionine). Accordingly, in the rat, under conditions of discontinuous enteral nutrition the mixture of small peptides was of greater nutritive value than the mixture of free amino acids. It thus appears that the absorption kinetics which results in important variations in the temporal distribution of free amino acids in the tissues may be at the origin of transitory imbalances in tissue amino acid uptake, and as a result of a lower nutritive value.

21 CFR 172.320 - Amino acids.

Code of Federal Regulations, 2012 CFR

2012-04-01

... of total protein (expressed as free amino acid) L-Alanine 6.1 L-Arginine 6.6 L-Aspartic acid... DL-Methionine 3.1 L-Phenylalanine 5.8 L-Proline 4.2 L-Serine 8.4 L-Threonine 5.0 L-Tryptophan 1.6 L... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Amino acids. 172.320 Section 172.320 Food and...

21 CFR 172.320 - Amino acids.

Code of Federal Regulations, 2011 CFR

2011-04-01

... of total protein (expressed as free amino acid) L-Alanine 6.1 L-Arginine 6.6 L-Aspartic acid... DL-Methionine 3.1 L-Phenylalanine 5.8 L-Proline 4.2 L-Serine 8.4 L-Threonine 5.0 L-Tryptophan 1.6 L... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Amino acids. 172.320 Section 172.320 Food and...

21 CFR 172.320 - Amino acids.

Code of Federal Regulations, 2013 CFR

2013-04-01

... of total protein (expressed as free amino acid) L-Alanine 6.1 L-Arginine 6.6 L-Aspartic acid... DL-Methionine 3.1 L-Phenylalanine 5.8 L-Proline 4.2 L-Serine 8.4 L-Threonine 5.0 L-Tryptophan 1.6 L... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Amino acids. 172.320 Section 172.320 Food and...

H NMR studies of substrate hydrogen exchange reactions catalyzed by L-methionine gamma-lyase

DOE Office of Scientific and Technical Information (OSTI.GOV)

Esaki, N.; Nakayama, T.; Sawada, S.

Hydrogen exchange reactions of various L-amino acids catalyzed by L-methionine gamma-lyase (EC 4.4.1.11) have been studied. The enzyme catalyzes the rapid exchange of the alpha- and beta-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium from the solvent. The rate of alpha-hydrogen exchange was about 40 times faster than that of the enzymatic elimination reaction of the sulfur-containing amino acids. The enzyme also catalyzes the exchange reaction of alpha- and beta-hydrogens of the straight-chain L-amino acids which are not susceptible to elimination. The exchange rates of the alpha-hydrogen and the total beta-hydrogens of L-alanine and L-alpha-aminobutyrate with deuterium followed first-order kinetics. Formore » L-norvaline, L-norleucine, S-methyl-L-cysteine, and L-methionine, the rate of alpha-hydrogen exchange followed first-order kinetics, but the rate of total beta-hydrogen exchange decreased due to a primary isotope effect at the alpha-position. L-Phenylalanine and L-tryptophan slowly underwent alpha-hydrogen exchange. The pro-R hydrogen of glycine was deuterated stereospecifically.« less

THE EFFECT OF dl-METHIONINE, l-CYSTINE, AND dl-ISOLEUCINE ON THE UTILIZATION OF PARENTERALLY ADMINISTERED DOG HEMOGLOBIN

PubMed Central

Miller, Leon L.; Alling, Eric L.

1947-01-01

1. Further observations on the utilization of parenterally administered dog hemoglobin show that oral supplements of dl-methionine and l-cystine improve the efficiency of utilization of hemoglobin N, while a fed supplement of dl-isoleucine alone is without effect. 2. When N-isoleucine is added to a fed supplement of methionine or methionine and cystine, the utilization of parenterally given hemoglobin N is even better than with the sulfur-containing amino acids alone. 3. A suggested approach to the problem of designing the quantitatively "ideal" amino acid mixture lies in the definition of what may be called total organism-amino acid patterns of rat, dog, man, etc. These may vary considerably not only at different developmental stages in a given species, but also certainly from one species to another. 4. Further attempts to detect globin in the peripheral circulation have pointed to the need for a highly specific procedure such as that an immunologic method may offer. 5. Reduced hemin in dog plasma migrates with α1-globulin and albumin in veronal buffer at pH 8.5 and the colored zones give strong hemochromogen absorption bands. PMID:19871599

Progress toward a reduced phage genetic code.

PubMed

Yao, Anzhi; Reed, Sean A; Koh, Minseob; Yu, Chenguang; Luo, Xiaozhou; Mehta, Angad P; Schultz, Peter G

2018-03-26

All known living organisms use at least 20 amino acids as the basic building blocks of life. Efforts to reduce the number of building blocks in a replicating system to below the 20 canonical amino acids have not been successful to date. In this work, we use filamentous phage as a model system to investigate the feasibility of removing methionine (Met) from the proteome. We show that all 24 elongation Met sites in the M13 phage genome can be replaced by other canonical amino acids. Most of these changes involve substitution of methionine by leucine (Leu), but in some cases additional compensatory mutations are required. Combining Met substituted sites in the proteome generally led to lower viability/infectivity of the mutant phages, which remains the major challenge in eliminating all methionines from the phage proteome. To date a total of 15 (out of all 24) elongation Mets have been simultaneously deleted from the M13 proteome, providing a useful foundation for future efforts to minimize the genetic code. Copyright © 2018. Published by Elsevier Ltd.

Potential for Development of an Escherichia coli—Based Biosensor for Assessing Bioavailable Methionine: A Review

PubMed Central

Chalova, Vesela I.; Froelich, Clifford A.; Ricke, Steven C.

2010-01-01

Methionine is an essential amino acid for animals and is typically considered one of the first limiting amino acids in animal feed formulations. Methionine deficiency or excess in animal diets can lead to sub-optimal animal performance and increased environmental pollution, which necessitates its accurate quantification and proper dosage in animal rations. Animal bioassays are the current industry standard to quantify methionine bioavailability. However, animal-based assays are not only time consuming, but expensive and are becoming more scrutinized by governmental regulations. In addition, a variety of artifacts can hinder the variability and time efficacy of these assays. Microbiological assays, which are based on a microbial response to external supplementation of a particular nutrient such as methionine, appear to be attractive potential alternatives to the already established standards. They are rapid and inexpensive in vitro assays which are characterized with relatively accurate and consistent estimation of digestible methionine in feeds and feed ingredients. The current review discusses the potential to develop Escherichia coli-based microbial biosensors for methionine bioavailability quantification. Methionine biosynthesis and regulation pathways are overviewed in relation to genetic manipulation required for the generation of a respective methionine auxotroph that could be practical for a routine bioassay. A prospective utilization of Escherichia coli methionine biosensor would allow for inexpensive and rapid methionine quantification and ultimately enable timely assessment of nutritional profiles of feedstuffs. PMID:22319312

21 CFR 172.320 - Amino acids.

Code of Federal Regulations, 2010 CFR

2010-04-01

... of total protein (expressed as free amino acid) L-Alanine 6.1 L-Arginine 6.6 L-Aspartic acid... DL-Methionine 3.1 L-Phenylalanine 5.8 L-Proline 4.2 L-Serine 8.4 L-Threonine 5.0 L-Tryptophan 1.6 L... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Amino acids. 172.320 Section 172.320 Food and Drugs...

Molecular cloning and characterization of l-methionine γ-lyase from Streptomyces avermitilis.

PubMed

Kudou, Daizou; Yasuda, Eri; Hirai, Yoshiyuki; Tamura, Takashi; Inagaki, Kenji

2015-10-01

A pyridoxal 5'-phosphate-dependent methionine γ-lyase (MGL) was cloned from Streptomyces avermitilis catalyzed the degradation of methionine to α-ketobutyrate, methanethiol, and ammonia. The sav7062 gene (1,242 bp) was corresponded to 413 amino acid residues with a molecular mass of 42,994 Da. The deduced amino acid sequence showed a high degree of similarity to those of other MGL enzymes. The sav7062 gene was overexpressed in Escherichia coli. The enzyme was purified to homogeneity and exhibited the MGL catalytic activities. We cloned the enzyme that has the MGL activity in Streptomyces for the first time. Copyright © 2015 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Temporal changes in concentrations of amino acids in plasma and whole blood of healthy neonatal foals from birth to two days of age.

PubMed

Zicker, S C; Rogers, Q R

1994-07-01

Temporal changes, as well as differences in distribution, in concentrations of 24 amino acids in plasma and whole blood of neonatal foals were determined from birth to 2 days of age. In addition, differences in concentrations of amino acids in plasma between mare and foal pairs were determined at birth. Significant (P < 0.05) hypoaminoacidemia existed for 15 amino acids in plasma of foals at birth, compared with mares (paired t-test). Concentrations of 7 amino acids (aspartate, glutamate, glutamine, glycine, hydroxyproline, phenylalanine, proline) in plasma of foals were higher (P < 0.05) at birth than in mares, and concentrations of 2 (taurine, tryptophan) were not different (P > 0.05). Significant (P < 0.05) temporal changes for concentrations of 19 of 24 amino acids in plasma were observed during the 48-hour period. Concentrations of 13 of the 19 amino acids in plasma that had significant changes were higher (P < 0.05) at 48 hours. Significant (P > 0.05) effect of time on concentration of 5 amino acids (alanine, methionine, phenylalanine, taurine, threonine) in plasma was not found after birth. Temporal changes in concentrations of 7 amino acids (alanine, asparagine, glutamine, histidine, hydroxyproline, methionine, and threonine) in whole blood were not significantly (P > 0.05) different from those in plasma. Temporal changes for concentrations of the remaining 17 amino acids in whole blood were significantly (P < 0.05) different, compared with plasma. Distribution of the concentrations of 18 amino acids between whole blood and plasma was significantly (P < 0.05) different.(ABSTRACT TRUNCATED AT 250 WORDS)

Separation and detection of amino acid metabolites of Escherichia coli in microbial fuel cell with CE.

PubMed

Wang, Wei; Ma, Lihong; Lin, Ping; Xu, Kaixuan

2016-07-01

In this work, CE-LIF was employed to investigate the amino acid metabolites produced by Escherichia coli (E. coli) in microbial fuel cell (MFC). Two peptides, l-carnosine and l-alanyl-glycine, together with six amino acids, cystine, alanine, lysine, methionine, tyrosine, arginine were separated and detected in advance by a CE-LIF system coupled with a homemade spontaneous injection device. The injection device was devised to alleviate the effect of electrical discrimination for analytes during sample injection. All analytes could be completely separated within 8 min with detection limits of 20-300 nmol/L. Then this method was applied to analyze the substrate solution containing amino acid metabolites produced by E. coli. l-carnosine, l-alanyl-glycine, and cystine were used as the carbon, nitrogen, and sulfur source for the E. coli culture in the MFC to investigate the amino acid metabolites during metabolism. Two MFCs were used to compare the activity of metabolism of the bacteria. In the sample collected at the running time 200 h of MFC, the amino acid methionine was discovered as the metabolite with the concentrations 23.3 μg/L. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Factors contributing to the resistivity of a higher casein diet against choline deficiency-induced hyperhomocysteinemia in rats.

PubMed

Liu, Yi-qun; Liu, Ying; Morita, Tatsuya; Mori, Makoto; Sugiyama, Kimio

2012-01-01

The mechanism by which feeding a higher casein diet results in resistance to choline deprivation-induced hyperhomocysteinemia was investigated in rats. Plasma homocysteine concentration was significantly lower in rats fed a 30% casein diet (30C) than in rats fed a 10% casein diet (10C). Choline deprivation did not enhance plasma homocysteine concentration in rats fed 30C, while it significantly enhanced plasma homocysteine concentration in rats fed 10C. The choline deprivation-induced enhancement of plasma homocysteine concentration in rats fed 10C was significantly suppressed by methionine supplementation in a dose-dependent manner in the range of 0.1 to 0.3%, but the suppressive effect of methionine became smaller with an increase in supplementation level in the range of 0.3 to 0.5%. At a 0.5% supplementation level, methionine did not exhibit any suppressive effect on choline deprivation-induced hyperhomocysteinemia. The higher plasma homocysteine concentration in rats fed choline-deprived 10C+0.5% methionine was significantly decreased by concurrent supplementation with 0.32% glycine+0.94% serine to the level of rats fed 10C. Raising dietary total amino acid level by adding 3.61% branched-chain amino acids (BCAA)+4.5% acidic amino acids (AAA) to choline-deprived 10C+0.5% methionine+0.32% glycine+0.94% serine resulted in a further decrease in plasma homocysteine concentration to a level lower than the level in rats fed 10C. Choline deprivation-induced increases in hepatic S-adenosylhomocysteine and homocysteine concentrations were significantly suppressed by supplementation with glycine+serine and further suppressed by BCAA+AAA. Hepatic cystathionine β-synthase activity and its gene expression were significantly increased by BCAA+AAA. Hepatic triglyceride concentration changed in a manner similar to that of plasma homocysteine concentration. The results indicate that there are at least three factors contributing to the resistivity of rats fed a higher casein diet (30C) to choline deprivation-induced hyperhomocysteinemia, i.e., higher intake of methionine, higher intake of glycine and serine, and higher intake of other amino acids such as BCAA and AAA.

Sulfur amino acid deficiency upregulates intestinal methionine cycle activity and suppresses epithelial growth in neonatal pigs

PubMed Central

Bauchart-Thevret, Caroline; Stoll, Barbara; Chacko, Shaji; Burrin, Douglas G.

2009-01-01

We recently showed that the developing gut is a significant site of methionine transmethylation to homocysteine and transsulfuration to cysteine. We hypothesized that sulfur amino acid (SAA) deficiency would preferentially reduce mucosal growth and antioxidant function in neonatal pigs. Neonatal pigs were enterally fed a control or an SAA-free diet for 7 days, and then whole body methionine and cysteine kinetics were measured using an intravenous infusion of [1-13C;methyl-2H3]methionine and [15N]cysteine. Body weight gain and plasma methionine, cysteine, homocysteine, and taurine and total erythrocyte glutathione concentrations were markedly decreased (−46% to −85%) in SAA-free compared with control pigs. Whole body methionine and cysteine fluxes were reduced, yet methionine utilization for protein synthesis and methionine remethylation were relatively preserved at the expense of methionine transsulfuration, in response to SAA deficiency. Intestinal tissue concentrations of methionine and cysteine were markedly reduced and hepatic levels were maintained in SAA-free compared with control pigs. SAA deficiency increased the activity of methionine metabolic enzymes, i.e., methionine adenosyltransferase, methionine synthase, and cystathionine β-synthase, and S-adenosylmethionine concentration in the jejunum, whereas methionine synthase activity increased and S-adenosylmethionine level decreased in the liver. Small intestine weight and protein and DNA mass were lower, whereas liver weight and DNA mass were unchanged, in SAA-free compared with control pigs. Dietary SAA deficiency induced small intestinal villus atrophy, lower goblet cell numbers, and Ki-67-positive proliferative crypt cells in association with lower tissue glutathione, especially in the jejunum. We conclude that SAA deficiency upregulates intestinal methionine cycle activity and suppresses epithelial growth in neonatal pigs. PMID:19293331

Effects of single amino acid deficiency on mRNA translation are markedly different for methionine versus leucine.

PubMed

Mazor, Kevin M; Dong, Leiming; Mao, Yuanhui; Swanda, Robert V; Qian, Shu-Bing; Stipanuk, Martha H

2018-05-24

Although amino acids are known regulators of translation, the unique contributions of specific amino acids are not well understood. We compared effects of culturing HEK293T cells in medium lacking either leucine, methionine, histidine, or arginine on eIF2 and 4EBP1 phosphorylation and measures of mRNA translation. Methionine starvation caused the most drastic decrease in translation as assessed by polysome formation, ribosome profiling, and a measure of protein synthesis (puromycin-labeled polypeptides) but had no significant effect on eIF2 phosphorylation, 4EBP1 hyperphosphorylation or 4EBP1 binding to eIF4E. Leucine starvation suppressed polysome formation and was the only tested condition that caused a significant decrease in 4EBP1 phosphorylation or increase in 4EBP1 binding to eIF4E, but effects of leucine starvation were not replicated by overexpressing nonphosphorylatable 4EBP1. This suggests the binding of 4EBP1 to eIF4E may not by itself explain the suppression of mRNA translation under conditions of leucine starvation. Ribosome profiling suggested that leucine deprivation may primarily inhibit ribosome loading, whereas methionine deprivation may primarily impair start site recognition. These data underscore our lack of a full understanding of how mRNA translation is regulated and point to a unique regulatory role of methionine status on translation initiation that is not dependent upon eIF2 phosphorylation.

Determination of the methionine requirement of male and female broiler chicks using an indirect amino acid oxidation method.

PubMed

Chamruspollert, M; Pesti, G M; Bakalli, R I

2002-07-01

The methionine requirement of 250-to-300-g broiler chicks was estimated from the oxidation of L-[1-14C] phenylalanine of chicks given meals containing graded levels of DL-methionine. L-[1-14C] phenylalanine was used as an indicator amino acid for amino acid oxidation and, indirectly, protein synthesis. Four experiments were conducted using an incomplete block design with three replications each. Chicks were crop intubated with semifluid diets at a ratio of 1 g of diet per 45 g of bird weight. Two feedings 2 h apart were used to reduce variability, and the sample collection period was 3 h after the second feeding. Regression analysis of 14CO2 release from L-[1-14C] phenylalanine was used to estimate the methionine requirement. The model was as follows: response = max + rc x (req - x) x I, where max = plateau, rc = rate constant, req = requirement, and I = 1 when x < req, otherwise I = 0. The methionine requirements of Ross x Ross chicks were 0.57 +/- 0.03% and 0.52 +/- 0.08% for male and female chicks, respectively in Experiment 1 and 0.55 +/- 0.05% and 0.52 +/- 0.04%, respectively, in Experiment 2. In the third experiment (Arbor Acre High-Yield), phenylalanine oxidation stabilized at a low rate when dietary methionine levels reached 0.54 +/- 0.03% and 0.53 +/- 0.04% for males and females, respectively. In a growth trial covering a longer period (Experiment 4), the methionine requirements of male and female Ross x Ross chicks, based on feed conversion, were 0.52 +/- 0.05% and 0.45 +/- 0.02%, respectively, and based on body gain were 0.54 +/0.09% and 0.48 +/- 0.04%, respectively. The results suggested that the methionine requirement of male chicks tended to be higher than that of females in both strains. However, differences were small and not significant.

Impact of food supplementation and methionine on high densities of cotton rats: Support of the amino-acid-quality hypothesis?

USGS Publications Warehouse

Webb, R.E.; Leslie, David M.; Lochmiller, R.L.; Masters, R.E.

2005-01-01

Considerable research supports the tenet that quantity and quality of food limit vertebrate populations. We evaluated predictions that increased availabilities of food and the essential amino acid methionine were related to population limitation of the hispid cotton rat (Sigmodon hispidus). Effects of supplemental food and methionine on density, survival, and reproductive parameters of wild cotton rats were assessed in north-central Oklahoma in 1998-1999. Twelve enclosed groups of 16 adult cotton rats each (8 male, 8 female) were randomly assigned to either no supplementation (control), supplementation with a mixed ration that had methionine at slightly below maintenance levels (0.20%), or a methionine-enhanced mixed ration (1.20%). In general, densities of cotton rats were twice as high and were sustained longer with dietary supplementation, and methionine-supplemented populations maintained the highest densities. Treatment effects on survival depended on time of year, with higher survival in supplemented enclosures in October and November. Per capita recruitment was highest with methionine-enhanced food. Treatment effects on proportions of overall and female cotton rats in reproductive condition depended on sampling date, but males were most reproductively active with methionine supplementation. Methionine supplementation resulted in an earlier and longer reproductive season. Density-dependent and density-independent factors no doubt interplay to determine population dynamics of cotton rats, but our results suggest that methionine plays a role in the population dynamics of wild cotton rats, apparently by enhancing overall density, recruitment, and reproductive activity of males.

Amelioration of ethionine toxicity in the chick.

PubMed

Lowry, K R; Baker, D H

1987-06-01

Several chick bioassays were conducted to evaluate means of ameliorating ethionine toxicity. Supplementing a corn-soy diet marginally deficient in sulfur amino acids (methionine + cystine) with .075% D,L-ethionine reduced weight gain in 8-day-old chicks by 70% compared to gains of unsupplemented controls. Dietary addition of .50% DL-methionine prevented reduction in weight gain and feed intake resulting from ethionine supplementation whereas feeding supplemental L-cystine was without effect. Supplementation of the ethionine-containing diet with either choline or betaine ameliorated the growth depression, although neither compound was able to completely overcome the toxic effects of ethionine. Dietary ethionine did not affect plasma levels of free methionine or cystine but did increase plasma free glycine 6-fold. Dietary addition of .50% DL-methionine caused normalization of plasma glycine levels whereas it elevated plasma methionine concentration. Although results suggested the possibility of ethionine-induced serine or threonine deficiency, dietary additions of .75% L-serine or .75% L-threonine failed to improve chick weight gain. These studies suggest that ethionine, in addition to affecting transsulfuration and transmethylation activity may exert specific effects on certain amino acids in tissue pools.

Effects of running the Bostom Marathon on plasma concentrations of large neutral amino acids

NASA Technical Reports Server (NTRS)

Conlay, L. A.; Wurtman, R. J.; Lopez G-Coviella, I.; Blusztajn, J. K.; Vacanti, C. A.; Logue, M.; During, M.; Caballero, B.; Maher, T. J.; Evoniuk, G.

1989-01-01

Plasma large neutral amino acid concentrations were measured in thirty-seven subjects before and after completing the Boston Marathon. Concentrations of tyrosine, phenylalanine, and methionine increased, as did their 'plasma ratios' (i.e., the ratio of each amino acid's concentration to the summed plasma concentrations of the other large neutral amino acids which compete with it for brain uptake). No changes were noted in the plasma concentrations of tryptophan, leucine, isoleucine, nor valine; however, the 'plasma ratios' of valine, leucine, and isoleucine all decreased. These changes in plasma amino acid patterns may influence neurotransmitter synthesis.

Targeting Amino Acid Metabolism for Molecular Imaging of Inflammation Early After Myocardial Infarction.

PubMed

Thackeray, James T; Bankstahl, Jens P; Wang, Yong; Wollert, Kai C; Bengel, Frank M

2016-01-01

Acute tissue inflammation after myocardial infarction influences healing and remodeling and has been identified as a target for novel therapies. Molecular imaging holds promise for guidance of such therapies. The amino acid (11)C-methionine is a clinically approved agent which is thought to accumulate in macrophages, but not in healthy myocytes. We assessed the suitability of positron emission tomography (PET) with (11)C-methionine for imaging post-MI inflammation, from cell to mouse to man. Uptake assays demonstrated 7-fold higher (11)C-methionine uptake by polarized pro-inflammatory M1 macrophages over anti-inflammatory M2 subtypes (p<0.001). C57Bl/6 mice (n=27) underwent coronary artery ligation or no surgery. Serial (11)C-methionine PET was performed 3, 5 and 7d later. MI mice exhibited a perfusion defect in 32-50% of the left ventricle (LV). PET detected increased (11)C-methionine accumulation in the infarct territory at 3d (5.9±0.9%ID/g vs 4.7±0.9 in remote myocardium, and 2.6±0.5 in healthy mice; p<0.05 and <0.01 respectively), which declined by d7 post-MI (4.3±0.6 in infarct, 3.4±0.8 in remote; p=0.03 vs 3d, p=0.08 vs healthy). Increased (11)C-methionine uptake was associated with macrophage infiltration of damaged myocardium. Treatment with anti-integrin antibodies (anti-CD11a, -CD11b, -CD49d; 100µg) lowered macrophage content by 56% and (11)C-methionine uptake by 46% at 3d post-MI. A patient study at 3d after ST-elevation MI and early reperfusion confirmed elevated (11)C-methionine uptake in the hypoperfused myocardial region. Targeting of elevated amino acid metabolism in pro-inflammatory M1 macrophages enables PET imaging-derived demarcation of tissue inflammation after MI. (11)C-methionine-based molecular imaging may assist in the translation of novel image-guided, inflammation-targeted regenerative therapies.

Targeting Amino Acid Metabolism for Molecular Imaging of Inflammation Early After Myocardial Infarction

PubMed Central

Thackeray, James T.; Bankstahl, Jens P.; Wang, Yong; Wollert, Kai C.; Bengel, Frank M.

2016-01-01

Acute tissue inflammation after myocardial infarction influences healing and remodeling and has been identified as a target for novel therapies. Molecular imaging holds promise for guidance of such therapies. The amino acid 11C-methionine is a clinically approved agent which is thought to accumulate in macrophages, but not in healthy myocytes. We assessed the suitability of positron emission tomography (PET) with 11C-methionine for imaging post-MI inflammation, from cell to mouse to man. Uptake assays demonstrated 7-fold higher 11C-methionine uptake by polarized pro-inflammatory M1 macrophages over anti-inflammatory M2 subtypes (p<0.001). C57Bl/6 mice (n=27) underwent coronary artery ligation or no surgery. Serial 11C-methionine PET was performed 3, 5 and 7d later. MI mice exhibited a perfusion defect in 32-50% of the left ventricle (LV). PET detected increased 11C-methionine accumulation in the infarct territory at 3d (5.9±0.9%ID/g vs 4.7±0.9 in remote myocardium, and 2.6±0.5 in healthy mice; p<0.05 and <0.01 respectively), which declined by d7 post-MI (4.3±0.6 in infarct, 3.4±0.8 in remote; p=0.03 vs 3d, p=0.08 vs healthy). Increased 11C-methionine uptake was associated with macrophage infiltration of damaged myocardium. Treatment with anti-integrin antibodies (anti-CD11a, -CD11b, -CD49d; 100µg) lowered macrophage content by 56% and 11C-methionine uptake by 46% at 3d post-MI. A patient study at 3d after ST-elevation MI and early reperfusion confirmed elevated 11C-methionine uptake in the hypoperfused myocardial region. Targeting of elevated amino acid metabolism in pro-inflammatory M1 macrophages enables PET imaging-derived demarcation of tissue inflammation after MI. 11C-methionine-based molecular imaging may assist in the translation of novel image-guided, inflammation-targeted regenerative therapies. PMID:27570549

Studies on the protein and sulfur amino acid requirements of young bobwhite quail

USGS Publications Warehouse

Serafin, J.A.

1977-01-01

Four experiments were conducted with purified diets to examine the influence of protein level and to estimate the sulfur amino acid (S.A.A.) requirement of young Bobwhite quail (Colinus virginianus). These studies demonstrated (I) that 26% protein was sufficient for rapid growth when the diet was supplemented with methionine; (2) that diets containing higher levels of protein (29.3% and 31.3%) failed to support satisfactory growth unless they contained supplemental methionine; and (3) that young Bobwhite quail require no more than 1.0% sulfur-containing amino acids for optimal growth and efficiency of feed utilization. A fifth experiment was conducted to examine the protein and S.A.A. requirements of young Bobwhite quail using practical rations and to compare results with those obtained with purified diets. Diets containing 24%, 26% and 28% protein were supplied with and without supplemental methionine in a five week study. Results showed significant growth responses to protein and supplemental methionine. Responses showed that Bobwhite quail require no more than 26% protein for maximum growth and efficiency of feed utilization when the S.A.A. level of the diet was approximately 1.0%. The results were in close agreement with those obtained with purified diets. These findings define more precisely than had been known the quantitative requirements of young Bobwhite quail for protein and for the S.A.A. necessary for optimal growth.

Free amino acid profiling in the giant puffball mushroom (Calvatia gigantea) using UPLC-MS/MS.

PubMed

Kıvrak, İbrahim; Kıvrak, Şeyda; Harmandar, Mansur

2014-09-01

Wild edible and medicinal mushroom, Calvatia gigantea, was quantitatively analyzed for the determination of its free amino acids using ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS). The concentrations of total free amino acids, essential and non-essential amino acids were 199.65 mg/100 g, 113.69 mg/100 g, and 85.96 mg/100 g in C. gigantea, respectively. This study showed that C. gigantea, so called a giant puffball mushroom, has free amino acids content. The essential amino acids: tryptophan, isoleucine, valine, phenylalanine, leucine, threonine, lysine, histidine, methionine, and the non-essential amino acids: tyrosine, 4-hyrdroxy proline, arginine, proline, glycine, serine, alanine, glutamine, glutamic acid, aspargine, aspartic acid were detected. Copyright © 2014 Elsevier Ltd. All rights reserved.

Analysis of the free amino acid content in pollen of nine Asteraceae species of known allergenic activity.

PubMed

Mondal, A K; Parui, S; Mandal, S

1998-01-01

The study reports the free amino acid composition of the pollen of nine members of the family Asteraceae, i.e. Ageratum conyzoides L., Blumea oxyodonta DC., Eupatorium odoratum L., Gnaphalium indicum L., Mikania scandens Willd., Parthenium hysterophorus L., Spilanthes acmella Murr., Vernonia cinerea (L.) Lees. and Xanthium strumarium L. by thin layer chromatography. The amino acid content was found to vary from 0.5-4.0% of the total dry weight. Fourteen amino acids were identified, among which amino-n-butyric acid, aspartic acid and proline were present in almost all pollen samples. The other major amino acids present in free form included arginine, cystine, glutamic acid, glycine, isoleucine, leucine, methionine, ornithine, tryptophan and tyrosine.

Sulfur in Distillers Grains for Dairy Cattle

USDA-ARS?s Scientific Manuscript database

Sulfur is an essential element needed by animals for many functions. About 0.15% of the body weight is sulfur. It is found in the amino acids methionine, cysteine, cystine, homocysteine, and taurine; in chondroitin sulfate of cartilage; and in the B-vitamins, thiamin and biotin. Methionine, thiam...

Methionine deficiency in rats fed soy protein induces hypercholesterolemia and potentiates lipoprotein susceptibility to peroxidation.

PubMed

Moundras, C; Rémésy, C; Levrat, M A; Demigné, C

1995-09-01

A number of studies have provided evidence that plant proteins, especially soy protein, have a cholesterol-lowering effect as compared with casein. However, dietary supply of sulfur amino acids may be deficient when soy protein is present in the diet at a suboptimal level, which could affect lipid metabolism. Accordingly, in rats fed 13% protein diets, soy protein feeding resulted in a cholesterol-increasing effect (+18%), which could be counteracted by methionine supplementation (0.4%). In contrast, soy protein was effective in decreasing plasma triglyceride, as compared with levels in rats fed casein; this triglyceride-lowering effect was entirely abolished by methionine supplementation. The hypercholesterolemic effect of soy protein was characterized by a higher cholesterol content in low-density lipoprotein (LDL) and high-density lipoprotein 1 (HDL1) fractions, together with a marked induction of hepatic hydroxymethyl glutaryl coenzyme A (HMG CoA) reductase activity and to a lesser extent cholesterol 7 alpha-hydroxylase. There was practically no induction of these enzymes, as compared with levels in rats fed casein diets, when the soy protein diet was supplemented with methionine. Very-low-density lipoprotein (VLDL) plus LDL susceptibility to peroxidation was higher in rats fed soy protein than in casein-fed rats, which could reflect in part the lack of sulfur amino acid availability, since methionine supplementation led to a partial recovery of lipoprotein resistance to peroxidation. These findings suggest that amino acid imbalance could be atherogenic by increasing circulating cholesterol and leading to a higher lipoprotein susceptibility to peroxidation.

Regulation of the proteome by amino acids.

PubMed

Bourgoin-Voillard, Sandrine; Goron, Arthur; Seve, Michel; Moinard, Christophe

2016-03-01

Besides their main contribution as substrates for protein synthesis, amino acids as signaling molecules could exert some regulatory functions on protein synthesis and/or proteolysis that have been emphasized in a number of recent studies. Several publications have highlighted supplemental roles of those amino acids in protein metabolism as well as in immunity, heat shock response, or apoptosis processes. In this way, via their regulatory properties, selected amino acids (such as leucine, glutamine, arginine, citrulline, or methionine) directly influence the proteome. In this review, we are proposing an overview of the regulation of the proteome by amino acids in mammals. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Relative reactivity of amino acids with chlorine in mixtures.

PubMed

Na, Chongzheng; Olson, Terese M

2007-05-01

The relative reactivity of chlorine with amino acids is an important determinant of the resulting chlorination products in systems where chlorine is the limiting reagent, for example, in the human gastrointestinal tract after consumption of chlorine-containing water, or during food preparation with chlorinated water. Since few direct determinations of the initial reactivity of chlorine with amino acids have been made, 17 amino acids were compared in this study using competitive kinetic principles. The experimental results showed that (1) most amino acids have similar initial reactivities at neutral pH; (2) amino acids with thiol groups such as methionine and cysteine are exceptionally reactive and produce sulfoxides; (3) amino acids without thiol groups primarily undergo monochlorination of the amino nitrogen; and (4) glycine and proline are the least reactive. Dichlorination was estimated to occur with approximately 26% of the amino acid groups when the total amino acid: chlorine concentrations were equal.

Effect of leucine-to-methionine substitutions on the diffraction quality of histone chaperone SET/TAF-Ibeta/INHAT crystals.

PubMed

Senda, Miki; Muto, Shinsuke; Horikoshi, Masami; Senda, Toshiya

2008-10-01

One of the most frequent problems in crystallization is poor quality of the crystals. In order to overcome this obstacle several methods have been utilized, including amino-acid substitutions of the target protein. Here, an example is presented of crystal-quality improvement by leucine-to-methionine substitutions. A variant protein with three amino-acid substitutions enabled improvement of the crystal quality of the histone chaperone SET/TAF-Ibeta/INHAT when combined with optimization of the cryoconditions. This procedure improved the resolution of the SET/TAF-Ibeta/INHAT crystals from around 5.5 to 2.3 A without changing the crystallization conditions.

Co-expression of bacterial aspartate kinase and adenylylsulfate reductase genes substantially increases sulfur amino acid levels in transgenic alfalfa (Medicago sativa L.).

PubMed

Tong, Zongyong; Xie, Can; Ma, Lei; Liu, Liping; Jin, Yongsheng; Dong, Jiangli; Wang, Tao

2014-01-01

Alfalfa (Medicago sativa L.) is one of the most important forage crops used to feed livestock, such as cattle and sheep, and the sulfur amino acid (SAA) content of alfalfa is used as an index of its nutritional value. Aspartate kinase (AK) catalyzes the phosphorylation of aspartate to Asp-phosphate, the first step in the aspartate family biosynthesis pathway, and adenylylsulfate reductase (APR) catalyzes the conversion of activated sulfate to sulfite, providing reduced sulfur for the synthesis of cysteine, methionine, and other essential metabolites and secondary compounds. To reduce the feedback inhibition of other metabolites, we cloned bacterial AK and APR genes, modified AK, and introduced them into alfalfa. Compared to the wild-type alfalfa, the content of cysteine increased by 30% and that of methionine increased substantially by 60%. In addition, a substantial increase in the abundance of essential amino acids (EAAs), such as aspartate and lysine, was found. The results also indicated a close connection between amino acid metabolism and the tricarboxylic acid (TCA) cycle. The total amino acid content and the forage biomass tested showed no significant changes in the transgenic plants. This approach provides a new method for increasing SAAs and allows for the development of new genetically modified crops with enhanced nutritional value.

Choline supplementation alters some amino acid concentrations with no change in homocysteine in children with cystic fibrosis and pancreatic insufficiency.

PubMed

Alshaikh, Belal; Schall, Joan I; Maqbool, Asim; Mascarenhas, Maria; Bennett, Michael J; Stallings, Virginia A

2016-05-01

The present study determined the plasma amino acid status in children with cystic fibrosis (CF) and pancreatic insufficiency (PI) in the modern medical and nutritional care setting and investigated the effect of choline supplementation on amino acid status. A total of 110 children aged 5 to 18 years with CF and PI were randomized to receive choline-enriched structured lipid (LYM-X-SORB) or placebo with similar energy and fat content. Plasma amino acids were measured at baseline and 3 and 12 months. We hypothesized that choline supplementation would result in lower plasma homocysteine concentrations in children with CF. At baseline, dietary protein intake was high and the amino acid profile was within laboratory reference ranges in most participants. Alanine and cysteine were elevated in 24% and 36% of participants, respectively. Children with baseline alanine above reference range had improved weight, body mass index, and fat-free mass. Low homocysteine was found in 62% of children 11 years and older. After 3 and 12 months, there was no effect of choline supplementation on methionine or homocysteine status. Compared with placebo, choline supplementation resulted in increased glycine and decreased threonine, histidine, valine, and total branch chained amino acids at 12 months. In conclusion, daily choline supplementation with LYM-X-SORB did not alter methionine-homocysteine metabolism but did result in alterations in other amino acids in children with CF and PI. Copyright © 2016 Elsevier Inc. All rights reserved.

Choline Supplementation Alters Some Amino Acid Concentrations with No Change in Homocysteine in Children with Cystic Fibrosis and Pancreatic Insufficiency

PubMed Central

Alshaikh, Belal; Schall, Joan I.; Maqbool, Asim; Mascarenhas, Maria; Bennett, Michael J.; Stallings, Virginia A.

2016-01-01

The present study determined the plasma amino acid status in children with cystic fibrosis (CF) and pancreatic insufficiency (PI) in the modern medical and nutritional care setting and investigated the effect of choline supplementation on amino acid status. A total of 110 children, ages 5 to 18 years, with CF and PI were randomized to receive choline-enriched structured lipid (LYM-X-SORB™, LXS) or placebo with similar calorie and fat content. Plasma amino acids were measured at baseline, 3, and 12 months. We hypothesized that choline supplementation would result in lower plasma homocysteine concentrations in children with CF. At baseline, dietary protein intake was high and the amino acid profile was within laboratory reference ranges in most subjects. Alanine and cysteine were elevated in 24% and 36% of subjects, respectively. Children with baseline alanine above reference range had improved weight, body mass index, and fat-free mass. Low homocysteine was found in 62% of children 11 years and older. After 3 and 12 months, there was no effect of choline supplementation on methionine or homocysteine status. Compared to placebo, choline supplementation resulted in increased glycine and decreased threonine, histidine, valine and total branch chained amino acids at 12 months. In conclusion, daily choline supplementation with LXS did not alter methionine-homocysteine metabolism but did result in alterations in other amino acids in children with CF and PI. PMID:27101760

Manipulation of dietary methionine+cysteine and threonine in broilers significantly decreases environmental nitrogen excretion.

PubMed

Donato, D C Z; Sakomura, N K; Silva, E P; Troni, A R; Vargas, L; Guagnoni, M A N; Meda, B

2016-06-01

The intensification of livestock have increased the emission of pollutants to the environment, leading to a growing interest in seeking strategies that minimise these emissions. Studies have shown that it is possible to manipulate diets by reducing CP levels and thus reducing nitrogen (N) excretion, without compromising performance. However, there is no knowledge of any study that has focused on reducing N excretion and relating this reduction to individual amino acids. This study investigated the effect of dietary methionine+cysteine (MC) and threonine (THR), the two most limiting amino acids for broiler production, on nitrogen excretion (NE) and nitrogen deposition (ND) and determined the efficiency of utilisation of both amino acids for protein deposition. Six trials were conducted to measure the NE and ND in broiler chickens during three rearing phases in response to dietary amino acid. The efficiency of utilisation of the amino acids was calculated by linear regression of body protein deposition and the amino acid intake. Despite the differences between sexes and phases, the efficiency of utilisation was the same, being 0.60 and 0.59 for MC and THR, respectively. The rate of NE behaved exponentially, increasing with amino acid intake, and can exceed 50% of N intake, being higher than ND. On average, for a reduction in intake of each unit of MC or THR (mg) there is a reduction of 0.5% of NE. Although this reduction seems low, considering that it corresponds to changes in one amino acid only, the impact on a large scale would be significant. Knowledge of how animals respond to NE and ND/protein deposition according to amino acid dietary content may represent new efforts towards reducing the impact on environment.

Enhanced Biocide Mitigation of Field Biofilm Consortia by a Mixture of D-Amino Acids

PubMed Central

Li, Yingchao; Jia, Ru; Al-Mahamedh, Hussain H.; Xu, Dake; Gu, Tingyue

2016-01-01

Microbiologically influenced corrosion (MIC) is a major problem in the oil and gas industry as well as in many other industries. Current treatment methods rely mostly on pigging and biocide dosing. Biocide resistance is a growing concern. Thus, it is desirable to use biocide enhancers to improve the efficacy of existing biocides. D-Amino acids are naturally occurring. Our previous work demonstrated that some D-amino acids are biocide enhancers. Under a biocide stress of 50 ppm (w/w) hydroxymethyl phosphonium sulfate (THPS) biocide, 1 ppm D-tyrosine and 100 ppm D-methionine used separately successfully mitigated the Desulfovibrio vulgaris biofilm on carbon steel coupons. The data reported in this work revealed that 50 ppm of an equimolar mixture of D-methionine, D-tyrosine, D-leucine, and D-tryptophan greatly enhanced 50 ppm THPS biocide treatment of two recalcitrant biofilm consortia containing sulfate reducing bacteria (SRB), nitrate reducing bacteria (NRB), and fermentative bacteria, etc., from oil-field operations. The data also indicated that individual D-amino acids were inadequate for the biofilm consortia. PMID:27379039

The effects of L-cysteine and N-acetyl-L-cysteine on homocysteine metabolism and haemostatic markers, and on cardiac and aortic histology in subchronically methionine-treated Wistar male rats.

PubMed

Kostić, Sanja; Mićovic, Žarko; Andrejević, Lazar; Cvetković, Saša; Stamenković, Aleksandra; Stanković, Sanja; Obrenović, Radmila; Labudović-Borović, Milica; Hrnčić, Dragan; Jakovljević, Vladimir; Djurić, Dragan

2018-06-23

Methionine is the precursor of homocysteine, a sulfur amino acid intermediate in the methylation and transsulfuration pathways; methionine-rich diets were used to induce hyperhomocysteinemia, and cardiovascular pathology was often observed. Other sulfur amino acids interfere with this metabolism, i.e., L-cysteine (Cys) and N-aceyl-L-cysteine (NAC), and probably also affect cardiovascular system. Their effects are controversial due to their ability to act both as anti- or pro-oxidant. Thus, this study aimed to elucidate their influence on levels of homocysteine, folate and vitamin B12, levels of different haemostatic parameters (fibrinogen, D-dimer, vWF Ag, vWF Ac) in rat serum or plasma as well as their effects on cardiac and aortic tissue histology in subchronically methionine-treated rats. Wistar albino rats were divided into 4 experimental groups: (a) control group (0.9% sodium chloride 0.1-0.2 mL/day) (n = 10) (K); (b) DL-methionine (0.8 mmol/kg/bw/day) (n = 10) (M); (c) DL-methionine (0.8 mmol/kg/bw/day) + L-cysteine (7 mg/kg/bw/day) (n = 8) (C); (d) DL-methionine (0.8 mmol/ kg/bw/day) + N-acetyl-L-cysteine (50 mg/kg/bw/day) (n = 8) (N). All substances were applied i.p., treatment duration 3 weeks. Lower levels of vitamin B12 in all the groups were found. Folate was reduced only in N group. Decreased fibrinogen was noted in C and N groups and increased D-dimer only in C. VWF activity was reduced in M and C groups. Deleterious effects in heart were observed, especially after Cys and NAC application. Aortic tissue remained unchanged. In conclusion, it could be said that sulfur amino acids have the significant impact on cardiovascular system in subchronically methionine-treated rats. This study points out the relevance of their complex interactions and deleterious effects mediated by either direct influence or procoagulant properties.

Capillary electrophoresis tandem mass spectrometry determination of glutamic acid and homocysteine's metabolites: Potential biomarkers of amyotrophic lateral sclerosis.

PubMed

Cieslarova, Zuzana; Lopes, Fernando Silva; do Lago, Claudimir Lucio; França, Marcondes Cavalcante; Colnaghi Simionato, Ana Valéria

2017-08-01

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease that affects both lower and upper motor neurons, leading to muscle atrophy, paralysis, and death caused by respiratory failure or infectious complications. Altered levels of homocysteine, cysteine, methionine, and glutamic acid have been observed in plasma of ALS patients. In this context, a method for determination of these potential biomarkers in plasma by capillary electrophoresis tandem mass spectrometry (CE-MS/MS) is proposed herein. Sample preparation was carefully investigated, since sulfur-containing amino acids may interact with plasma proteins. Owing to the non-thiol sulfur atom in methionine, it was necessary to split sample preparation into two methods: i) determination of homocysteine and cysteine as S-acetyl amino acids; ii) determination of glutamic acid and methionine. All amino acids were separated within 25min by CE-MS/MS using 5molL -1 acetic acid as background electrolyte and 5mmolL -1 acetic acid in 50% methanol/H 2 O (v/v) as sheath liquid. The proposed CE-MS/MS method was validated, presenting RSD values below 6% and 11% for intra- and inter-day precision, respectively, for the middle concentration level within the linear range. The limits of detection ranged from 35 (homocysteine) to 268nmolL -1 (glutamic acid). The validated method was applied to the analysis of plasma samples from a group of healthy individuals and patients with ALS, showing the potential of glutamic acid and homocysteine metabolites as biomarkers of ALS. Copyright © 2017 Elsevier B.V. All rights reserved.

Effects of methionine and betaine supplementation on growth performance, carcase composition and metabolism of lipids in male broilers.

PubMed

Zhan, X A; Li, J X; Xu, Z R; Zhao, R Q

2006-10-01

1. This study was conducted to investigate the effects of methionine and betaine supplementation on growth performance, carcase composition and lipid metabolism in growing broilers. 2. A total of 450 commercial broilers, 22 d of age, were randomly allocated to three groups, each of which included three replicates (50 birds per replicate). The groups received the same methionine-deficient diet supplemented with 0 or 1 g/kg methionine, or 0.5 g/kg betaine, respectively. 3. Methionine and betaine supplementation significantly improved weight gain and feed conversion. Supplemental methionine and betaine also significantly increased breast muscle yield and decreased abdominal fat content. Meanwhile, addition of methionine and betaine significantly increased the contents of creatine and free carnitine in liver, the activity of hormone-sensitive lipase in abdominal fat and the concentration of free fatty acid in serum, whereas uric acid concentration in serum was significantly decreased. 4. The results of this study suggest that betaine can spare methionine in its function as an essential amino acid and is as effective as methionine in improving performance and carcase quality of growing broilers if the diet is moderately deficient in methionine. The decrease in abdominal fat may be due to the increased carnitine synthesis in liver and hormone-sensitive lipase activity in abdominal fat.

Betaine is as effective as folate at re-synthesizing methionine for protein synthesis during moderate methionine deficiency in piglets.

PubMed

McBreairty, Laura E; Robinson, Jason L; Harding, Scott V; Randell, Edward W; Brunton, Janet A; Bertolo, Robert F

2016-12-01

Both folate and betaine (synthesized from choline) are nutrients used to methylate homocysteine to reform the amino acid methionine following donation of its methyl group; however, it is unclear whether both remethylation pathways are of equal importance during the neonatal period when remethylation rates are high. Methionine is an indispensable amino acid that is in high demand in neonates not only for protein synthesis, but is also particularly important for transmethylation reactions, such as creatine and phosphatidylcholine synthesis. The objective of this study was to determine whether supplementation with folate, betaine, or a combination of both can equally re-synthesize methionine for protein synthesis when dietary methionine is limiting. Piglets were fed a low methionine diet devoid of folate, choline, and betaine, and on day 6, piglets were supplemented with either folate, betaine, or folate + betaine (n = 6 per treatment) until day 10. [1- 13 C]-phenylalanine oxidation was measured as an indicator of methionine availability for protein synthesis both before and after 2 days of supplementation. Prior to supplementation, piglets had lower concentrations of plasma folate, betaine, and choline compared to baseline with no change in homocysteine. Post-supplementation, phenylalanine oxidation levels were 20-46 % lower with any methyl donor supplementation (P = 0.006) with no difference among different supplementation groups. Furthermore, both methyl donors led to similarly lower concentrations of homocysteine following supplementation (P < 0.05). These data demonstrate an equal capacity for betaine and folate to remethylate methionine for protein synthesis, as indicated by lower phenylalanine oxidation.

Synthesis of new Cα-tetrasubstituted α-amino acids

PubMed Central

Grauer, Andreas A

2009-01-01

Summary Cα-Tetrasubstituted α-amino acids are important building blocks for the synthesis of peptidemimetics with stabilized secondary structure, because of their ability to rigidify the peptide backbone. Recently our group reported a new class of cyclic Cα-tetrasubstituted tetrahydrofuran α-amino acids prepared from methionine and aromatic aldehydes. We now report the extension of this methodology to aliphatic aldehydes. Although such aldehydes are prone to give aldol products under the reaction conditions used, we were able to obtain the target cyclic amino acids in low to moderate yields and in some cases with good diastereoselectivity. PMID:19259341

Distribution and enantiomeric composition of amino acids in the Murchison meteorite

NASA Technical Reports Server (NTRS)

Engel, M. H.; Nagy, B.

1982-01-01

Studies of the amino acid contents and enantiomeric compositions of a single stone from the Murchison meteorite are reported. Water-extracted and 6M HCl-extracted samples from the meteorite interior of meteorite fragments were analyzed by gas chromatography and combined gas chromatography-chemical ionization mass spectrometry. Examination of the D/L ratios of glutamic acid, aspartic acid, proline, leucine and alanine reveals those amino acids extractable by water to be partially racemized, whereas the acid-extracted amino acids were less racemized. The amino acid composition of the stone is similar to those previously reported, including the absence of serine, threonine, tyrosine phenylalanine and methionine and the presence of unusual amino acids including such as isovaline, alpha-aminoisobutyric acid and pseudoleucine. It is concluded that the most likely mechanism accounting for the occurrence of nonracemic amino acid mixtures in the Murchison meteorite is by extraterrestrial stereoselective synthesis or decomposition reactions.

Sulfur amino acid and methyl donor status of corn-soy diets fed to starting broiler chicks and turkey poults.

PubMed

Pesti, G M; Harper, A E; Sunde, M L

1979-11-01

Experiments were conducted to determine the effects of supplementing corn-soy-bean meal-white grease diets with sulfur amino acids and methyl group donors for starting broiler-strain chicks. The diets (23% protein and 3200 kcal ME/kg) were fed to quadruplicate lots of chicks in battery brooders. The diets were calculated to contain .37% methionine, .37% cystine, and 1499 mg/kg choline. Chemical and microbiological assays yielded values of .32% and .42% for methionine and cystine content respectively. Results of 5 chick experiments showed that supplementing this diet with .23% DL-methionine significantly (P less than .05) improved 3 week-gain (375 vs. 415 g) and feed/gain (1.54 vs. 1.47) over that obtained with the basal diet. When L-cystine and 2(CaSO4).H2O failed to give a significant (P greater than .05) response, compounds capable of donating methyl groups were fed. Significant (P less than .05) responses in gain (404 and 420) and feed/gain (1.48 and 1.51) over the basal were obtained with choline and betaine. These responses were not significantly (P greater than .05) different from that obtained with methionine. Serine and sodium formate failed to give consistent responses. Using a poult diet of 28% protein and 2800 kcal ME/kg, a significant (P less than .05) response to DL-methionine was again observed, with intermediate responses to betaine, choline, and serine. It is concluded that (within the limits of the experimental model) corn-soy type diets contain an adequate amount of total sulfur amino acid for chicks, but not poults, when sufficient choline or betaine are provided.

Antioxidative Categorization of Twenty Amino Acids Based on Experimental Evaluation.

PubMed

Xu, Naijin; Chen, Guanqun; Liu, Hui

2017-11-27

In view of the great importance bestowed on amino acids as antioxidants in oxidation resistance, we attempted two common redox titration methods in this report, including micro-potassium permanganate titration and iodometric titration, to measure the antioxidative capacity of 20 amino acids, which are the construction units of proteins in living organisms. Based on the relative intensities of the antioxidative capacity, we further conducted a quantitative comparison and found out that the product of experimental values obtained from the two methods was proven to be a better indicator for evaluating the relative antioxidative capacity of amino acids. The experimental results were largely in accordance with structural analysis made on amino acids. On the whole, the 20 amino acids concerned could be divided into two categories according to their antioxidative capacity. Seven amino acids, including tryptophan, methionine, histidine, lysine, cysteine, arginine and tyrosine, were greater in total antioxidative capacity compared with the other 13 amino acids.

Correlation Between Gastric Emptying and Gastric Adaptive Relaxation Influenced by Amino Acids

PubMed Central

Uchida, Masayuki; Kobayashi, Orie; Saito, Chizuru

2017-01-01

Background/Aims Amino acids have many physiological activities. We report the correlation between gastric emptying and gastric adaptive relaxation using tryptophan and amino acids with a straight alkyl chain, hydroxylated chain, and branched chain. Here we sought to further clarify the correlation between gastric emptying and gastric adaptive relaxation by using other amino acids. Methods In Sprague-Dawley rats, gastric emptying was evaluated by a breath test using [1-13C] acetic acid. The expired 13CO2 pattern, Tmax, Cmax, and AUC120min values were used as evaluation items. Gastric adaptive relaxation was evaluated in a barostat experiment. Individual amino acids (1 g/kg) were administered orally 30 minutes before each breath test or barostat test. Results L-phenylalanine and L-tyrosine did not influence gastric emptying. All other amino acids, ie, L-proline, L-histidine, L-cysteine, L-methionine, L-aspartic acid, L-glutamic acid, L-asparagine, L-arginine, L-glutamine, and L-lysine significantly delayed and inhibited gastric emptying. L-Cysteine and L-aspartic acid significantly enhanced and L-methionine and L-glutamine significantly inhibited gastric adaptive relaxation. L-Phenylalanine moved the balloon toward the antrum, suggesting strong contraction of the fundus. Tmax showed a significant positive correlation (r = 0.709), and Cmax and AUC120min each showed negative correlations (r = 0.613 and 0.667, respectively) with gastric adaptive relaxation. Conclusion From the above findings, it was found that a close correlation exists between gastric emptying and adaptive relaxation, suggesting that enhanced gastric adaptive relaxation inhibits gastric emptying. PMID:28335103

Influence of methionine/valine-depleted enteral nutrition on nucleic acid and protein metabolism in tumor-bearing rats

PubMed Central

He, Yin-Cheng; Cao, Jun; Chen, Ji-Wei; Pan, Ding-Yu; Zhou, Ya-Kui

2003-01-01

AIM: To investigate the effects of methionine/valine-depleted enteral nutrition (EN) on RNA, DNA and protein metabolism in tumor-bearing (TB) rats. METHODS: Sprague-Dawlley (SD) rats underwent jejunostomy for nutritional support. A suspension of Walker-256 carcinosarcoma cells was subcutaneously inoculated. 48 TB rats were randomly divided in 4 groups: A, B, C and D. The TB rats had respectively received jejunal feedings supplemented with balanced amino acids, methionine-depleted, balanced amino acids and valine-depleted for 6 d before injection of 740 KBq 3H- methionine/valine via jejunum. The 3H incorporation rate of the radioactivity into RNA, DNA and proteins in tumor tissues at 0.5, 1, 2, 4 h postinjection of tracers was assessed with liquid scintillation counter. RESULTS: Incorporation of 3H into proteins in groups B and D was (0.500 ± 0.020)% to (3.670 ± 0.110)% and (0.708 ± 0.019)% to (3.813 ± 0.076)% respectively, lower than in groups A [(0.659 ± 0.055)% to (4.492 ± 0.108)%] and C [(0.805 ± 0.098)% to (4.180 ± 0.018)%]. Incorporation of 3H into RNA, DNA in group B was (0.237 ± 0.075)% and (0.231 ± 0.052)% respectively, lower than in group A (P < 0.01). There was no significant difference in uptake of 3H by RNA and DNA between group C and D (P > 0.05). CONCLUSION: Protein synthesis was inhibited by methionine/valine starvation in TB rats and nucleic acid synthesis was reduced after methionine depletion, thus resulting in suppression of tumor growth. PMID:12679929

The absorption of protons with specific amino acids and carbohydrates by yeast

PubMed Central

Seaston, A.; Inkson, C.; Eddy, A. A.

1973-01-01

1. Proton uptake in the presence of various amino acids was studied in washed yeast suspensions containing deoxyglucose and antimycin to inhibit energy metabolism. A series of mutant strains of Saccharomyces cerevisiae with defective amino acid permeases was used. The fast absorption of glycine, l-citrulline and l-methionine through the general amino acid permease was associated with the uptake of about 2 extra equivalents of protons per mol of amino acid absorbed, whereas the slower absorption of l-methionine, l-proline and, possibly, l-arginine through their specific permeases was associated with about 1 proton equivalent. l-Canavanine and l-lysine were also absorbed with 1–2 equivalents of protons. 2. A strain of Saccharomyces carlsbergensis behaved similarly with these amino acids. 3. Preparations of the latter yeast grown with maltose subsequently absorbed it with 2–3 equivalents of protons. The accelerated rate of proton uptake increased up to a maximum value with the maltose concentration (Km=1.6mm). The uptake of protons was also faster in the presence of α-methylglucoside and sucrose, but not in the presence of glucose, galactose or 2-deoxyglucose. All of these compounds except the last could cause acid formation. The uptake of protons induced by maltose, α-methylglucoside and sucrose was not observed when the yeast was grown with glucose, although acid was then formed both from sucrose and glucose. 4. A strain of Saccharomyces fragilis that both fermented and formed acid from lactose absorbed extra protons in the presence of lactose. 5. The observations show that protons were co-substrates in the systems transporting the amino acids and certain of the carbohydrates. PMID:4587071

Development and validation of a rapid, selective, and sensitive LC-MS/MS method for simultaneous determination of D- and L-amino acids in human serum: application to the study of hepatocellular carcinoma.

PubMed

Han, Minlu; Xie, Mengyu; Han, Jun; Yuan, Daoyi; Yang, Tian; Xie, Ying

2018-04-01

A validated liquid chromatography-tandem mass spectrometry method was developed for the simultaneous determination of D- and L-amino acids in human serum. Under the optimum conditions, except for DL-proline, L-glutamine, and D-lysine, the enantioseparation of the other 19 enantiomeric pairs of proteinogenic amino acids and nonchiral glycine was achieved with a CROWNPAK CR-I(+) chiral column within 13 min. The lower limits of quantitation for L-amino acids (including glycine) and D-amino acids were 5-56.25 μM and 0.625-500 nM, respectively, in human serum. The intraday precision and interday precision for all the analytes were less than 15%, and the accuracy ranged from -12.84% to 12.37% at three quality control levels. The proposed method, exhibiting high rapidity, enantioresolution, and sensitivity, was successfully applied to the quantification of D- and L-amino acid levels in serum from hepatocellular carcinoma patients and healthy individuals. The serum concentrations of L-arginine, L-isoleucine, L-aspartate, L-tryptophan, L-alanine, L-methionine, L-serine, glycine, L-valine, L-leucine, L-phenylalanine, L-threonine, D-isoleucine, D-alanine, D-glutamate, D-glutamine, D-methionine, and D-threonine were significantly reduced in the hepatocellular carcinoma patients compared with the healthy individuals (P < 0.01). D-Glutamate and D-glutamine were identified as the most downregulated serum markers (fold change greater than 1.5), which deserves further attention in hepatocellular carcinoma research. Graphical abstract Simultaneous determination of D- and L-amino acids in human serum from hepatocellular carcinoma patients and healthy individuals. AA amino acid, HCC hepatocellular carcinoma, LC liquid chromatography, MS/MS tandem mass spectrometry, NC normal control, TIC total ion chromatogram.

Oxidation of Methionine Residues in Polypeptide Ions via Gas-Phase Ion/Ion Chemistry

PubMed Central

Pilo, Alice L.; McLuckey, Scott A.

2014-01-01

The gas-phase oxidation of methionine residues is demonstrated here using ion/ion reactions with periodate anions. Periodate anions are observed to attach to varying degrees to all polypeptide ions irrespective of amino acid composition. Direct proton transfer yielding a charge reduced peptide ion is also observed. In the case of methionine and, to a much lesser degree, tryptophan containing peptide ions, collisional activation of the complex ion generated by periodate attachment yields an oxidized peptide product (i.e., [M+H+O]+), in addition to periodic acid detachment. Detachment of periodic acid takes place exclusively for peptides that do not contain either a methionine or tryptophan side-chain. In the case of methionine containing peptides, the [M+H+O]+ product is observed at a much greater abundance than the proton transfer product (viz., [M+H]+). Collisional activation of oxidized Met-containing peptides yields a signature loss of 64 Da from the precursor and/or product ions. This unique loss corresponds to the ejection of methanesulfenic acid from the oxidized methionine side chain and is commonly used in solution-phase proteomics studies to determine the presence of oxidized methionine residues. The present work shows that periodate anions can be used to ‘label’ methionine residues in polypeptides in the gas-phase. The selectivity of the periodate anion for the methionine side chain suggests several applications including identification and location of methionine residues in sequencing applications. PMID:24671696

Studies on the biochemical composition, energetics and essential amino acids of three mudskippers in Xiamen Harbour

NASA Astrophysics Data System (ADS)

Wang, Jun; Su, Yong-Quan

1995-12-01

Measurements were made on the contents of protein, lipid, glycogen (PLG) and water, and on caloric values and amino acids, in muscle of three mudskippers Periophthalmus cantonensis, Scarteiaos viridis and Boleophthalmus pectinirostris collected from Haicang, Xiamen. The essential amino acids (EAA) for these fishes were also studied with radioisotopic trace method. The results showed: (1) The content of each component in tested fish muscles differed slightly, and protein was the most important component making up from 6.685% to 9.891% of the wet weight (about 44.21% 50.45% of dry weight); (2) Energy calculated from the sum of protein, lipid and glycogen in wet muscle was low (<4.3kJ/g) in these fishes, especially in B. pectinirostris (<3.1 kJ/g); the ratios of energy to protein content ( E/P) also were low (<39.873 45.535kJ/g); (3) Seventeen amino acids were determined in these three fishes. The content of the same amino acid (among the seventeen) tested in different species and sexes varied slightly. The amounts of methionine, phenylalanine lysine, arginine, histidine, threonine isoleucine and leucine which are indispensable for the needs of human beings and animals were relatively high, accounting for 47.35% 48.06% of the total amino acid content. (4) Leucine, isoleucine, arginine, lysine, phenylalanine, tryptophan, methionine, histidine, threonine, and valine, are essential in the diet of the three mudskippers as the radioisotopic trace method using D-[U-14C]-glucose showed little or no radioactivity was incorporated into these ten amino acids.

Studies on the biochemical composition, energetics and essential amino acids of three mudskippers in Xiamen Harbour

NASA Astrophysics Data System (ADS)

Jun, Wang; Yong-Quan, Su

1995-12-01

Measurements were made on the contents of protein, lipid, glycogen (PLG) and water, and on caloric values and amino acids, in muscle of three mudskippers Periophthalmus cantonensis, Scarteiaos viridis and Boleophthalmus pectinirostris collected from Haicang, Xiamen. The essential amino acids (EAA) for these fishes were also studied with radioisotopic trace method. The results showed: (1) The content of each component in tested fish muscles differed slightly, and protein was the most important component making up from 6.685% to 9.891% of the wet weight (about 44.21%-50.45% of dry weight); (2) Energy calculated from the sum of protein, lipid and glycogen in wet muscle was low (<4.3kJ/g) in these fishes, especially in B. pectinirostris (<3.1 kJ/g); the ratios of energy to protein content ( E/P) also were low (<39.873-45.535kJ/g); (3) Seventeen amino acids were determined in these three fishes. The content of the same amino acid (among the seventeen) tested in different species and sexes varied slightly. The amounts of methionine, phenylalanine lysine, arginine, histidine, threonine isoleucine and leucine which are indispensable for the needs of human beings and animals were relatively high, accounting for 47.35%-48.06% of the total amino acid content. (4) Leucine, isoleucine, arginine, lysine, phenylalanine, tryptophan, methionine, histidine, threonine, and valine, are essential in the diet of the three mudskippers as the radioisotopic trace method using D-[U-14C]-glucose showed little or no radioactivity was incorporated into these ten amino acids.

Influence of dietary protein level on the broiler chicken's response to methionine and betaine supplements.

PubMed

Garcia Neto, M; Pesti, G M; Bakalli, R I

2000-10-01

Two experiments were conducted to compare broiler chicken responses to methionine and betaine supplements when fed diets with low protein and relatively high metabolizable energy levels (17%, 3.3 kcal/g) or moderate protein and lower metabolizable energy levels (24%, 3.0 kcal/g), resulting in different levels of carcass fat. In Experiment 1, the basal diets were formulated with corn, soybean meal, poultry by-product meal, and poultry oil. In Experiment 2, glucose monohydrate was also added, so that identical amino acid profiles could be maintained in the 17 and 24% protein diets. On average, feeding the 17 vs. 24% protein diet decreased 21-d body weight gain by 20%, increased feed conversion ratio (FCR) by 13%, and increased abdominal fat pad weight by 104%. Methionine and betaine supplements improved the performance of chicks fed the 24% protein diet in both experiments, as indicated by body weight gain and FCR. Only supplementary methionine increased performance of chicks fed 17% protein diets, and then only in Experiment 2. Neither methionine nor betaine decreased abdominal fat pad size in either experiment. Methionine supplementation decreased relative liver size and increased breast muscle protein. Both methionine and betaine increased sample feather weight, but when expressed as a percentage of body weight, no significant differences were detected. It is concluded that increasing carcass fat by manipulating percentage dietary protein level or amino acid balance does not influence betaine's activity as a lipotropic agent.

Co-Expression of Bacterial Aspartate Kinase and Adenylylsulfate Reductase Genes Substantially Increases Sulfur Amino Acid Levels in Transgenic Alfalfa (Medicago sativa L.)

PubMed Central

Tong, Zongyong; Xie, Can; Ma, Lei; Liu, Liping; Jin, Yongsheng; Dong, Jiangli; Wang, Tao

2014-01-01

Alfalfa (Medicago sativa L.) is one of the most important forage crops used to feed livestock, such as cattle and sheep, and the sulfur amino acid (SAA) content of alfalfa is used as an index of its nutritional value. Aspartate kinase (AK) catalyzes the phosphorylation of aspartate to Asp-phosphate, the first step in the aspartate family biosynthesis pathway, and adenylylsulfate reductase (APR) catalyzes the conversion of activated sulfate to sulfite, providing reduced sulfur for the synthesis of cysteine, methionine, and other essential metabolites and secondary compounds. To reduce the feedback inhibition of other metabolites, we cloned bacterial AK and APR genes, modified AK, and introduced them into alfalfa. Compared to the wild-type alfalfa, the content of cysteine increased by 30% and that of methionine increased substantially by 60%. In addition, a substantial increase in the abundance of essential amino acids (EAAs), such as aspartate and lysine, was found. The results also indicated a close connection between amino acid metabolism and the tricarboxylic acid (TCA) cycle. The total amino acid content and the forage biomass tested showed no significant changes in the transgenic plants. This approach provides a new method for increasing SAAs and allows for the development of new genetically modified crops with enhanced nutritional value. PMID:24520364

Activation of Nrf2 is required for up-regulation of the π class of glutathione S-transferase in rat primary hepatocytes with L-methionine starvation.

PubMed

Lin, Ai-Hsuan; Chen, Haw-Wen; Liu, Cheng-Tze; Tsai, Chia-Wen; Lii, Chong-Kuei

2012-07-04

Numerous genes expression is regulated in response to amino acid shortage, which helps organisms adapt to amino acid limitation. The expression of the π class of glutathione (GSH) S-transferase (GSTP), a highly inducible phase II detoxification enzyme, is regulated mainly by activates activating protein 1 (AP-1) binding to the enhancer I of GSTP (GPEI). Here we show the critical role of nuclear factor erythroid-2-related factor 2 (Nrf2) in up-regulating GSTP gene transcription. Primary rat hepatocytes were cultured in a methionine-restricted medium, and immunoblotting and RT-PCR analyses showed that methionine restriction time-dependently increased GSTP protein and mRNA expression over a 48 h period. Nrf2 translocation to the nucleus, nuclear proteins binding to GPEI, and antioxidant response element (ARE) luciferase reporter activity were increased by methionine restriction as well as by l-buthionine sulfoximine (BSO), a GSH synthesis inhibitor. Transfection with Nrf2 siRNA knocked down Nrf2 expression and reversed the methionine-induced GSTP expression and GPEI binding activity. Chromatin immunoprecipitation assay confirmed the binding of Nrf2 to the GPEI. Phosphorylation of extracellular signal-regulated kinase 2 (ERK2) was increased in methionine-restricted and BSO-treated cells. ERK2 siRNA abolished methionine restriction-induced Nrf2 nuclear translocation, GPEI binding activity, ARE-luciferase reporter activity, and GSTP expression. Our results suggest that the up-regulation of GSTP gene transcription in response to methionine restriction likely occurs via the ERK-Nrf2-GPEI signaling pathway.

Subcritical Water Hydrolysis of Peptides: Amino Acid Side-Chain Modifications

NASA Astrophysics Data System (ADS)

Powell, Thomas; Bowra, Steve; Cooper, Helen J.

2017-09-01

Previously we have shown that subcritical water may be used as an alternative to enzymatic digestion in the proteolysis of proteins for bottom-up proteomics. Subcritical water hydrolysis of proteins was shown to result in protein sequence coverages greater than or equal to that obtained following digestion with trypsin; however, the percentage of peptide spectral matches for the samples treated with trypsin were consistently greater than for those treated with subcritical water. This observation suggests that in addition to cleavage of the peptide bond, subcritical water treatment results in other hydrolysis products, possibly due to modifications of amino acid side chains. Here, a model peptide comprising all common amino acid residues (VQSIKCADFLHYMENPTWGR) and two further model peptides (VCFQYMDRGDR and VQSIKADFLHYENPTWGR) were treated with subcritical water with the aim of probing any induced amino acid side-chain modifications. The hydrolysis products were analyzed by direct infusion electrospray tandem mass spectrometry, either collision-induced dissociation or electron transfer dissociation, and liquid chromatography collision-induced dissociation tandem mass spectrometry. The results show preferential oxidation of cysteine to sulfinic and sulfonic acid, and oxidation of methionine. In the absence of cysteine and methionine, oxidation of tryptophan was observed. In addition, water loss from aspartic acid and C-terminal amidation were observed in harsher subcritical water conditions. [Figure not available: see fulltext.

Effect of L-methionine supplementation on plasma homocysteine and other free amino acids: a placebo-controlled double-blind cross-over study.

PubMed

Ditscheid, B; Fünfstück, R; Busch, M; Schubert, R; Gerth, J; Jahreis, G

2005-06-01

The essential amino acid L-methionine is a potential compound in the prophylaxis of recurrent or relapsing urinary tract infection due to acidification of urine. As an intermediate of L-methionine metabolism, homocysteine is formed. The objective was to study the metabolism of L-methionine and homocysteine, and to assess whether there are differences between patients with chronic urinary tract infection and healthy control subjects. A randomized placebo-controlled double-blind intervention study with cross-over design. Department of Nutritional Physiology, Institute of Nutrition in cooperation with the Department of Internal Medicine III, Friedrich Schiller University of Jena, Germany. Eight female patients with chronic urinary tract infection and 12 healthy women (controls). After a methionine-loading test, the volunteers received 500 mg L-methionine or a placebo three times daily for 4 weeks. Serum and urinary concentrations of methionine, homocysteine, cystathionine, cystine, serine, glycine and serum concentrations of vitamin B12, B6 and the state of folate. Homocysteine plasma concentrations increased from 9.4+/-2.7 micromol/l (patients) and 8.9+/-1.8 micromol/l (controls) in the placebo period to 11.2+/-4.1 micromol/l (P=0.031) and 11.0+/-2.3 micromol/l (P=0.000), respectively, during L-methionine supplementation. There were significant increases in serum methionine (53.6+/-22.0 micromol/l; P=0.003; n=20) and cystathionine (0.62+/-0.30 micromol/l; P=0.000; n=20) concentrations compared with the placebo period (33.0+/-12.0 and 0.30+/-0.10 micromol/l; n=20). Simultaneously, renal excretion of methionine and homocysteine was significantly higher during L-methionine intake. Despite an adequate vitamin status, the supplementation of 1500 mg of L-methionine daily significantly increases homocysteine plasma concentrations by an average of 2.0 micromol/l in patients and in control subjects. An optimal vitamin supplementation, especially with folate, might prevent such an increase.

Model-based identification of optimal operating conditions for amino acid simulated moving bed enantioseparation using a macrocyclic glycopeptide stationary phase.

PubMed

Fuereder, Markus; Majeed, Imthiyas N; Panke, Sven; Bechtold, Matthias

2014-06-13

Teicoplanin aglycone columns allow efficient separation of amino acid enantiomers in aqueous mobile phases and enable robust and predictable simulated moving bed (SMB) separation of racemic methionine despite a dependency of the adsorption behavior on the column history (memory effect). In this work we systematically investigated the influence of the mobile phase (methanol content) and temperature on SMB performance using a model-based optimization approach that accounts for methionine solubility, adsorption behavior and back pressure. Adsorption isotherms became more favorable with increasing methanol content but methionine solubility was decreased and back pressure increased. Numerical optimization suggested a moderate methanol content (25-35%) for most efficient operation. Higher temperature had a positive effect on specific productivity and desorbent requirement due to higher methionine solubility, lower back pressure and virtually invariant selectivity at high loadings of racemic methionine. However, process robustness (defined as a difference in flow rate ratios) decreased strongly with increasing temperature to the extent that any significant increase in temperature over 32°C will likely result in operating points that cannot be realized technically even with the lab-scale piston pump SMB system employed in this study. Copyright © 2014. Published by Elsevier B.V.

Introgression of leginsulin, a cysteine-rich protein, and high-protein trait from an Asian soybean plant introduction genotype into a North American experimental soybean line

USDA-ARS?s Scientific Manuscript database

Soybean is an important protein source for both humans and animals. However, soybean proteins are relatively poor in the sulfur-containing amino acids, cysteine and methionine. Improving the content of endogenous proteins rich in sulfur containing amino acids could enhance the nutritive value of soy...

Quantitative trait locus analysis of seed sulfur containing amino acids in two recombinant inbred line populations of soybean

USDA-ARS?s Scientific Manuscript database

Soybean (Glycine max (L.) Merr.) is a major source of plant protein for humans and livestock. Low levels of sulfur containing amino acids (cysteine and methionine) in soybean protein is the main limitation of soybean meal as animal food. The objectives of this study were to identify and validate Q...

Effect of amino acids and vitamins on laccase production by the bird's nest fungus Cyathus bulleri.

PubMed

Dhawan, Shikha; Kuhad, Ramesh Chander

2002-08-01

Various amino acids, their analogues and vitamins have shown stimulatory as well as inhibitory effects on laccase production by Cyathus bulleri. DL-methionine, DL-tryptophan, glycine and DL-valine stimulated laccase production, while L-cysteine monohydrochloride completely inhibited the enzyme production. Among vitamins tested biotin, riboflavin and pyridoxine hydrochloride were found to induce laccase production.

Aliphatic peptidyl hydroperoxides as a source of secondary oxidation in hydroxyl radical protein footprinting

PubMed Central

Saladino, Jessica; Liu, Mian; Live, David; Sharp, Joshua S.

2009-01-01

Hydroxyl radical footprinting is a technique for studying protein structure and binding that entails oxidizing a protein system of interest with diffusing hydroxyl radicals, and then measuring the amount of oxidation of each amino acid. One important issue in hydroxyl radical footprinting is limiting amino acid oxidation by secondary oxidants to prevent uncontrolled oxidation which can cause amino acids to appear more solvent accessible than they really are. Previous work suggested that hydrogen peroxide was the major secondary oxidant of concern in hydroxyl radical footprinting experiments; however, even after elimination of all hydrogen peroxide, some secondary oxidation was still detected. Evidence is presented for the formation of peptidyl hydroperoxides as the most abundant product upon oxidation of aliphatic amino acids. Both reverse phase liquid chromatography and catalase treatment were shown to be ineffective at eliminating peptidyl hydroperoxides. The ability of these peptidyl hydroperoxides to directly oxidize methionine is demonstrated, suggesting the value of methionine amide as an in situ protectant. Hydroxyl radical footprinting protocols require the use of an organic sulfide or similar peroxide scavenger in addition to removal of hydrogen peroxide in order to successfully eradicate all secondary oxidizing species and prevent uncontrolled oxidation of sulfur-containing residues. PMID:19278868

The long-term effect of zinc soil contamination on selected free amino acids playing an important role in plant adaptation to stress and senescence.

PubMed

Pavlíková, Daniela; Zemanová, Veronika; Procházková, Dagmar; Pavlík, Milan; Száková, Jiřina; Wilhelmová, Naďa

2014-02-01

Increased endogenous plant cytokinin (CK) content through transformation with an isopentyl transferase (ipt) gene has been associated with improved plant stress tolerance. The objective of this study is to determine amino acid changes associated with elevated CK production in ipt transgenic tobacco (Nicotiana tabacum L., cv. Wisconsin 38). Nontransformed (WT) and transformed tobacco plants with ipt gene controlled by senescence-activated promoter (SAG) were exposed to zinc soil contamination (tested levels Zn1=250, Zn2=500, Zn3=750 mg kg(-1) soil). The Zn effect on plant stress metabolism resulted in changes in levels of selected free amino acids playing an important role in adaptation to stress and plant senescence (alanine, leucine, proline, methionine and γ-aminobutyrate) and differed for transformed and nontransformed tobacco plants. Analyses of amino acids confirmed that SAG tobacco plants had improved zinc tolerance compared with the WT plants. The enhanced Zn tolerance of SAG plants was associated with the maintenance of accumulation of proline, methionine and γ-aminobutyrate. The concentrations of leucine and alanine did not show significant differences between plant lines. © 2013 Published by Elsevier Inc.

Surface Propensity of Atmospherically Relevant Amino Acids Studied by XPS.

PubMed

Mocellin, Alexandra; Gomes, Anderson Herbert de Abreu; Araújo, Oscar Cardoso; de Brito, Arnaldo Naves; Björneholm, Olle

2017-04-27

Amino acids constitute an important fraction of the water-soluble organic nitrogen (WSON) compounds in aerosols and are involved in many processes in the atmosphere. In this work, we applied X-ray photoelectron spectroscopy (XPS) to study aqueous solutions of four amino acids, glycine, alanine, valine, and methionine, in their zwitterionic forms. We found that amino acids with hydrophilic side chains and smaller size, GLY and ALA, tend to stay in the bulk of the liquid, while the hydrophobic and bigger amino acids, VAL and MET, are found to concentrate more on the surface. We found experimental evidence that the amino acids have preferential orientation relative to the surface, with the hydrophobic side chain being closer to the surface than the hydrophilic carboxylate group. The observed amino acid surface propensity has implications in atmospheric science as the surface interactions play a central role in cloud droplet formation, and they should be considered in climate models.

Combining affinity enrichment, cross-linking with photo-amino acids, and mass spectrometry for probing protein kinase D2 interactions.

PubMed

Häupl, Björn; Ihling, Christian H; Sinz, Andrea

2017-04-07

We present a novel approach that relies on the affinity capture of protein interaction partners from a complex mixture, followed by covalent fixation via UV-induced activation of incorporated diazirine photo-reactive amino acids (photo-methionine and photo-leucine). The captured protein complexes are enzymatically digested and interacting proteins are identified and quantified by label-free LC/MS analysis. Using HeLa cell lysates with photo-methionine and photo-leucine-labeled proteins, we were able to capture and preserve protein interactions that are otherwise elusive in conventional pull-down experiments. Our approach is exemplified for mapping the protein interaction network of protein kinase D2, but has the potential be applied to any protein system. Data are available via ProteomeXchange with identifiers PXD005346 (photo-amino acid incorporation) and PXD005349 (enrichment experiments). This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Repair of oxidative DNA damage by amino acids.

PubMed

Milligan, J R; Aguilera, J A; Ly, A; Tran, N Q; Hoang, O; Ward, J F

2003-11-01

Guanyl radicals, the product of the removal of a single electron from guanine, are produced in DNA by the direct effect of ionizing radiation. We have produced guanyl radicals in DNA by using the single electron oxidizing agent (SCN)2-, itself derived from the indirect effect of ionizing radiation via thiocyanate scavenging of OH. We have examined the reactivity of guanyl radicals in plasmid DNA with the six most easily oxidized amino acids cysteine, cystine, histidine, methionine, tryptophan and tyrosine and also simple ester and amide derivatives of them. Cystine and histidine derivatives are unreactive. Cysteine, methionine, tyrosine and particularly tryptophan derivatives react to repair guanyl radicals in plasmid DNA with rate constants in the region of approximately 10(5), 10(5), 10(6) and 10(7) dm3 mol(-1) s(-1), respectively. The implication is that amino acid residues in DNA binding proteins such as histones might be able to repair by an electron transfer reaction the DNA damage produced by the direct effect of ionizing radiation or by other oxidative insults.

Aspartokinase in Lemna minor L

PubMed Central

Wong, Kwan F.; Dennis, David T.

1973-01-01

The growth of Lemna minor was followed by means of frond number, fresh weight, and dry weight measurements in the presence of various amino acids at a concentration 0.25 mm. Lysine inhibited growth but not to the same extent as threonine and homoserine. Isoleucine was also an inhibitor of growth. In the presence of methionine there was some growth for 2 to 3 days, but by 5 days most of the plants appeared to be dead. When lysine and threonine were added together, there was no growth at all, and the plants were dead after 5 days. This effect of lysine + threonine could be reversed by adding methionine or homoserine to the growth medium. The isolated aspartokinase from Lemna showed inhibition by lysine and higher concentrations of threonine. When these amino acids were added together at low concentrations, there was a concerted inhibition of the aspartokinase. It is suggested that some effects of amino acids on the growth of L. minor can be explained on the basis of a concerted feedback control of aspartokinase. Images PMID:16658324

The effects of high dietary protein and nitrogen levels on the preformed methyl group requirement and methionine-induced growth depression in chicks.

PubMed

Pesti, G M; Benevenga, N J; Harper, A E; Sunde, M L

1981-02-01

The chick's choline and methionine requirements are both increased by high dietary protein level. Studies were conducted to test the hypothesis that the chicks' need for preformed methyl groups is increased by high protein diets (not methionine or choline per se). Chicks fed 25% isolated soybean protein (ISP) diets responded to methionine supplementation (162 vs 110 g gained in 14 days) but not to choline (119 g vs. 110 g), while those fed 50% ISP responded to either methionine (174 g vs. 126 g) or choline (181 g vs. 126 g) supplementation. Further, neither cystine nor homocystine could replace methionine in improving the growth of chicks fed the high protein diet. In other experiments, L-methionine and betaine HCl were found to alleviate the growth depression caused by excessive levels of L-glutamic acid. Excessive levels of L-methionine had a protective effect against growth depression caused by L-glutamate and diammonium citrate, and conversely, supplementary L-serine and sodium formate were not protective against glutamic acid- or arginine-induced growth depression. The results are consistent with the hypothesis that the preformed methyl group requirement is increased by high levels of dietary protein and excessive nitrogen from a single amino acid.

Concurrent Overexpression of Arabidopsis thaliana Cystathionine γ-Synthase and Silencing of Endogenous Methionine γ-Lyase Enhance Tuber Methionine Content in Solanum tuberosum.

PubMed

Kumar, Pavan; Jander, Georg

2017-04-05

Potatoes (Solanum tuberosum) are deficient in methionine, an essential amino acid in human and animal diets. Higher methionine levels increase the nutritional quality and promote the typically pleasant aroma associated with baked and fried potatoes. Several attempts have been made to elevate tuber methionine levels by genetic engineering of methionine biosynthesis and catabolism. Overexpressing Arabidopsis thaliana cystathionine γ-synthase (AtCGS) in S. tuberosum up-regulates a rate-limiting step of methionine biosynthesis and increases tuber methionine levels. Alternatively, silencing S. tuberosum methionine γ-lyase (StMGL), which causes decreased degradation of methionine into 2-ketobutyrate, also increases methionine levels. Concurrently enhancing biosynthesis and reducing degradation were predicted to provide further increases in tuber methionine content. Here we report that S. tuberosum cv. Désirée plants with AtCGS overexpression and StMGL silenced by RNA interference are morphologically normal and accumulate higher free methionine levels than either single-transgenic line.

Nuclear magnetic resonance studies of amino acids and proteins. Side-chain mobility of methionine in the crystalline amonio acid and in crystallne sperm whale (Physeter catodon) myoglobin

DOE Office of Scientific and Technical Information (OSTI.GOV)

Keniry, M.A.; Rothgeb, T.M.; Smith, R.L.

1983-04-12

Deuterium (/sup 2/H) nuclear magnetic resonance (NMR) spectra and spin-lattice relaxation times (T/sub 1/) were obtained of L-(epsilon-/sup 2/H/sub 3/)methionine, L-(epsilon-/sup 2/H/sub 3/)methionine in a D,L lattice, and (S-methyl-/sup 2/H/sub 3/)methionine in the crystalline solid state, as a function of temperature, in addition to obtaining /sup 2/H T/sub 1/ and line-width results as a function of temperature on (epsilon-/sup 2/H/sub 3/)methionine-labeled sperm whale (Physeter catodon) myoglobins by using the method of magnetic ordering. Also recorded were /sup 13/C cross-polarization ''magic-angle'' sample-spinning NMR spectra of (epsilon-/sup 13/C)methionine-labeled crystalline cyanoferrimyoglobin (at 37.7 MHz, corresponding to a magnetic field strength of 3.52 T)more » and of the same protein in aqueous solution. (JMT)« less

Investigation into the misincorporation of norleucine into a recombinant protein vaccine candidate.

PubMed

Ni, Joyce; Gao, Meg; James, Andrew; Yao, Jiansheng; Yuan, Tao; Carpick, Bruce; D'Amore, Tony; Farrell, Patrick

2015-06-01

A high level of norleucine misincorporation was detected in a recombinant methionine-rich protein vaccine candidate expressed in E. coli K12. An investigation was conducted to evaluate a simple remediation strategy to reduce norleucine misincorporation and to determine if the phenomenon was either (a) due to the depletion of methionine during fermentation, (b) a result of the cultivation environment, or (c) a strain-specific effect. While supplementation with exogenous methionine improved product quality, the undesirable biosynthesis of non-standard amino acids such as norleucine and norvaline persisted. In contrast, non-standard amino acid biosynthesis was quickly minimized upon selection of an appropriate fed-batch process control strategy, fermentation medium, and nutrient feed. By expressing the same protein in E. coli BL21(DE3), it was determined that the biosynthesis of norleucine and norvaline, and the misincorporation of norleucine into the protein were primarily attributed to the use of E. coli K12 as the host for protein expression.

Analysis of amino acids in nectar from pitchers of Sarracenia purpurea (Sarraceniaceae).

PubMed

Dress, W; Newell, S; Nastase, A; Ford, J

1997-12-01

Sarracenia purpurea L. (northern pitcher plant) is an insectivorous plant with extrafloral nectar that attracts insects to a water-filled pitfall trap. We identified and quantified the amino acids in extrafloral nectar produced by pitchers of S. purpurea. Nectar samples were collected from 32 pitchers using a wick-sampling technique. Samples were analyzed for amino acids with reverse-phase high-performance liquid chromatography with phenylisothiocyanate derivatization. Detectable amounts of amino acids were found in each of the 32 nectar samples tested. Mean number of amino acids in a nectar sample was 9 (SD = 2.2). No amino acid was detected in all 32 samples. Mean amount of amino acids in a nectar sample (i.e., amount per wick) was 351.4 ng (SD = 113.2). Nine amino acids occurred in 20 of the 32 samples (aspartic acid, cysteine, glutamic acid, glycine, histidine, hydroxyproline, methionine, serine, valine) averaging 263.4 ng (SD = 94.9), and accounting for ~75% of the total amino acid content. Nectar production may constitute a significant cost of carnivory since the nectar contains amino acids. However, some insects prefer nectar with amino acids and presence of amino acids may increase visitation and capture of insect prey.

Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: a cross-sectional analysis in the EPIC-Oxford cohort.

PubMed

Schmidt, J A; Rinaldi, S; Scalbert, A; Ferrari, P; Achaintre, D; Gunter, M J; Appleby, P N; Key, T J; Travis, R C

2016-03-01

We aimed to investigate the differences in plasma concentrations and in intakes of amino acids between male meat-eaters, fish-eaters, vegetarians and vegans in the Oxford arm of the European Prospective Investigation into Cancer and Nutrition. This cross-sectional analysis included 392 men, aged 30-49 years. Plasma amino acid concentrations were measured with a targeted metabolomic approach using mass spectrometry, and dietary intake was assessed using a food frequency questionnaire. Differences between diet groups in mean plasma concentrations and intakes of amino acids were examined using analysis of variance, controlling for potential confounding factors and multiple testing. In plasma, concentrations of 6 out of 21 amino acids varied significantly by diet group, with differences of -13% to +16% between meat-eaters and vegans. Concentrations of methionine, tryptophan and tyrosine were highest in fish-eaters and vegetarians, followed by meat-eaters, and lowest in vegans. A broadly similar pattern was seen for lysine, whereas alanine concentration was highest in fish-eaters and lowest in meat-eaters. For glycine, vegans had the highest concentration and meat-eaters the lowest. Intakes of all 18 dietary amino acids differed by diet group; for the majority of these, intake was highest in meat-eaters followed by fish-eaters, then vegetarians and lowest in vegans (up to 47% lower than in meat-eaters). Men belonging to different habitual diet groups have significantly different plasma concentrations of lysine, methionine, tryptophan, alanine, glycine and tyrosine. However, the differences in plasma concentrations were less marked than and did not necessarily mirror those seen for amino acid intakes.

Plasma concentrations and intakes of amino acids in male meat-eaters, fish-eaters, vegetarians and vegans: a cross-sectional analysis in the EPIC-Oxford cohort

PubMed Central

Schmidt, J A; Rinaldi, S; Scalbert, A; Ferrari, P; Achaintre, D; Gunter, M J; Appleby, P N; Key, T J; Travis, R C

2016-01-01

Background/Objectives: We aimed to investigate the differences in plasma concentrations and in intakes of amino acids between male meat-eaters, fish-eaters, vegetarians and vegans in the Oxford arm of the European Prospective Investigation into Cancer and Nutrition. Subjects/Methods: This cross-sectional analysis included 392 men, aged 30–49 years. Plasma amino acid concentrations were measured with a targeted metabolomic approach using mass spectrometry, and dietary intake was assessed using a food frequency questionnaire. Differences between diet groups in mean plasma concentrations and intakes of amino acids were examined using analysis of variance, controlling for potential confounding factors and multiple testing. Results: In plasma, concentrations of 6 out of 21 amino acids varied significantly by diet group, with differences of −13% to +16% between meat-eaters and vegans. Concentrations of methionine, tryptophan and tyrosine were highest in fish-eaters and vegetarians, followed by meat-eaters, and lowest in vegans. A broadly similar pattern was seen for lysine, whereas alanine concentration was highest in fish-eaters and lowest in meat-eaters. For glycine, vegans had the highest concentration and meat-eaters the lowest. Intakes of all 18 dietary amino acids differed by diet group; for the majority of these, intake was highest in meat-eaters followed by fish-eaters, then vegetarians and lowest in vegans (up to 47% lower than in meat-eaters). Conclusions: Men belonging to different habitual diet groups have significantly different plasma concentrations of lysine, methionine, tryptophan, alanine, glycine and tyrosine. However, the differences in plasma concentrations were less marked than and did not necessarily mirror those seen for amino acid intakes. PMID:26395436

Almond (Prunus dulcis L.) protein quality.

PubMed

Ahrens, Susan; Venkatachalam, Mahesh; Mistry, Anahita M; Lapsley, Karen; Sathe, Shridhar K

2005-09-01

Three marketing varieties of almonds; Carmel, Mission, and Nonpareil; were analyzed for proximate composition and protein nutritive quality. Moisture, lipids, protein, ash, sugars, and tannins ranges were 3.05-4.33%, 43.37-47.50%, 20.68-23.30%, 3.74-4.56%, 5.35-7.45%, and 0.12-0.18%, respectively. No detectable hemagglutinating and trypsin inhibitory activities were present in Carmel, Mission, and Nonpareil almonds. Amino acid analyses indicated the sulfur amino acids (methionine + cysteine), lysine, and threonine to be the first, second, and third limiting amino acids in almonds when compared to the recommended amino acid pattern for children 2-5-year old. However, compared to the recommended amino acid pattern for adults, sulfur amino acids were the only limiting amino acids in almonds tested. True Protein Digestibility (% TPD) values for Carmel, Mission, and Nonpareil were 88.55 +/- 1.26, 92.25 +/- 1.05, and 82.62 +/- 1.47, respectively. Protein Digestibility Corrected Amino Acid Scoring (PDCAAS) values suggested almond proteins to be of poor nutritional quality.

New developments in uses of "cereals and pulses," traditionally a basic food ingredient in the East

USDA-ARS?s Scientific Manuscript database

‘Cereals and pulses’ are very popular in the developing world. They provide a harmonious balance of amino acids, as pulses are high in lysine and low in methionine, while cereals are low in lysine and not in methionine. Over the years, a number of studies have been reported on improved nutritional ...

Metabolism of 5-methylthioribose to methionine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Miyazaki, J.H.; Yang, S.F.

1987-06-01

During ethylene biosynthesis, the H/sub 3/CS-group of S-adenosylmethionine is released as 5'-methylthioadenosine, which is recycled to methionine via 5-methylthioribose (MTR). In mungbean hypocotyls and cell-free extracts of avocado, (/sup 14/C)MTR was converted into labeled methionine via 2-keto-4-methylthiobutyric acid (KMB) and 2-hydroxy-4-methylthiobutyric acid (HMB), as intermediates. Incubation of (ribose-U-/sup 14/C)MTR with avocado extract resulted in the production of (/sup 14/C)formate, indicating the conversion of MTR to KMB involves a loss of formate, presumably from C-1 of MTR. Tracer studies showed that KMB was converted readily in vivo and in vitro to methionine, while HMB was converted much more slowly. The conversionmore » of KMB to methionine by dialyzed avocado extract requires an amino donor. Among several potential donors examined, L-glutamine was the most efficient. Anaerobiosis inhibited only partially the oxidation of MTR to formate, KMB/HMB, and methionine by avocado extract. The role of O/sub 2/ in the conversion of MTR to methionine is discussed.« less

D-Amino Acids Enhance the Activity of Antimicrobials against Biofilms of Clinical Wound Isolates of Staphylococcus aureus and Pseudomonas aeruginosa

DTIC Science & Technology

2014-05-19

and P. aeruginosa biofilms. Screening of dispersive activity of individual D-amino acids, D-methionine (D-Met), D- phenylalanine (D-Phe), and D...Microb. Ecol. http://dx.doi.org/10.1007/s00248 -013-0297-x. 16. Roche ED, Renick PJ, Tetens SP, Ramsay SJ, Daniels EQ, Carson DL . 2012. Increasing the

Analysis of common bean expressed sequence tags identifies sulfur metabolic pathways active in seed and sulfur-rich proteins highly expressed in the absence of phaseolin and major lectins

PubMed Central

2011-01-01

Background A deficiency in phaseolin and phytohemagglutinin is associated with a near doubling of sulfur amino acid content in genetically related lines of common bean (Phaseolus vulgaris), particularly cysteine, elevated by 70%, and methionine, elevated by 10%. This mostly takes place at the expense of an abundant non-protein amino acid, S-methyl-cysteine. The deficiency in phaseolin and phytohemagglutinin is mainly compensated by increased levels of the 11S globulin legumin and residual lectins. Legumin, albumin-2, defensin and albumin-1 were previously identified as contributing to the increased sulfur amino acid content in the mutant line, on the basis of similarity to proteins from other legumes. Results Profiling of free amino acid in developing seeds of the BAT93 reference genotype revealed a biphasic accumulation of gamma-glutamyl-S-methyl-cysteine, the main soluble form of S-methyl-cysteine, with a lag phase occurring during storage protein accumulation. A collection of 30,147 expressed sequence tags (ESTs) was generated from four developmental stages, corresponding to distinct phases of gamma-glutamyl-S-methyl-cysteine accumulation, and covering the transitions to reserve accumulation and dessication. Analysis of gene ontology categories indicated the occurrence of multiple sulfur metabolic pathways, including all enzymatic activities responsible for sulfate assimilation, de novo cysteine and methionine biosynthesis. Integration of genomic and proteomic data enabled the identification and isolation of cDNAs coding for legumin, albumin-2, defensin D1 and albumin-1A and -B induced in the absence of phaseolin and phytohemagglutinin. Their deduced amino acid sequences have a higher content of cysteine than methionine, providing an explanation for the preferential increase of cysteine in the mutant line. Conclusion The EST collection provides a foundation to further investigate sulfur metabolism and the differential accumulation of sulfur amino acids in seed of common bean. Identification of sulfur-rich proteins whose levels are elevated in seed lacking phaseolin and phytohemagglutinin and sulfur metabolic genes may assist the improvement of protein quality. PMID:21615926

Effect of multi-nutrient insufficiency on markers of one carbon metabolism in young women: response to a methionine load.

PubMed

Katre, P; Joshi, S; Bhat, D S; Deshmukh, M; Gurav, N; Pandit, S; Lubree, H; Marczewski, S; Bennett, C; Gruca, L; Kalyanaraman, K; Naik, S S; Yajnik, C S; Kalhan, S C

2016-06-01

Multi-nutrient insufficiencies as a consequence of nutritional and economic factors are common in India and other developing countries. We have examined the impact of multi-nutrient insufficiency on markers of one carbon (1C) metabolism in the blood, and response to a methionine load in clinically healthy young women. Young women from Pune, India (n=10) and Cleveland, USA (n=13) were studied. Blood samples were obtained in the basal state and following an oral methionine load (50 mg/kg of body weight in orange juice). Plasma concentrations of vitamin B12, folate and B6 were measured in the basal state. The effect of methionine load on the levels of methionine, total homocysteine, cysteine, glutathione and amino acids was examined. Indian women were significantly shorter and lighter compared with the American women and had lower plasma concentration of vitamins B12, folate and B6, essential amino acids and glutathione, but higher concentration of total homocysteine. The homocysteine response to methionine load was higher in Indian women. The plasma concentrations of glycine and serine increased in the Indian women after methionine (in juice) load. A significant negative correlation between plasma B6 and homocysteine (r= -0.70), and plasma folate and glycine and serine levels were observed in the Indian group (P<0.05) but not in the American group. Multi-nutrient insufficiency in the Indian women caused unique changes in markers of whole body protein and 1C metabolism. These data would be useful in developing nutrient intervention strategies.

Effect of technological processing and preservation method on amino acid content and protein quality in kale (Brassica oleracea L. var. acephala) leaves.

PubMed

Korus, Anna

2012-02-01

The aim of the investigation was to evaluate the level of amino acids and quality of protein in raw and processed kale leaves. In all samples the dominant amino acids in g kg⁻¹ raw matter were glutamic acid, aspartic acid and proline. In raw kale leaves the limiting amino acids were lysine, isoleucine and cystine with methionine, and in the remaining products also valine and leucine. Blanched kale leaves contained 88% of the amino acid content in raw leaves, 76% in cooked leaves, and 69-77% and 71-72% of initial levels in frozen and canned products, respectively. In raw, blanched and cooked leaves essential amino acids comprised 44%, 44% and 47%, respectively, of total amino acids; in frozen and canned leaves the proportions were 46% and 44%, respectively. The essential amino acid index was 97 for canned products, 100-109 for frozen leaves, and 117 for raw kale leaves. Raw and processed (blanched or cooked) kale leaves are a good source of amino acids. Copyright © 2011 Society of Chemical Industry.

Light-activated amino acid transport in Halobacterium halobium envelope vesicles

NASA Technical Reports Server (NTRS)

Macdonald, R. E.; Lanyi, J. K.

1977-01-01

Vesicles prepared from Halobacterium halobium cell envelopes accumulate amino acids in response to light-induced electrical and chemical gradients. Nineteen of 20 commonly occurring amino acids have been shown to be actively accumulated by these vesicles in response to illumination or in response to an artificially created Na+ gradient. On the basis of shared common carriers the transport systems can be divided into eight classes, each responsible for the transport of one or several amino acids: arginine, lysine, histidine; asparagine, glutamine; alanine, glycine, threonine, serine; leucine, valine, isoleucine, methionine; phenylalanine, tyrosine, tryptophan; aspartate; glutamate; proline. Available evidence suggests that these carriers are symmetrical in that amino acids can be transported equally well in both directions across the vesicle membranes. A tentative working model to account for these observations is presented.

Complete nucleotide and derived amino acid sequence of cDNA encoding the mitochondrial uncoupling protein of rat brown adipose tissue: lack of a mitochondrial targeting presequence.

PubMed Central

Ridley, R G; Patel, H V; Gerber, G E; Morton, R C; Freeman, K B

1986-01-01

A cDNA clone spanning the entire amino acid sequence of the nuclear-encoded uncoupling protein of rat brown adipose tissue mitochondria has been isolated and sequenced. With the exception of the N-terminal methionine the deduced N-terminus of the newly synthesized uncoupling protein is identical to the N-terminal 30 amino acids of the native uncoupling protein as determined by protein sequencing. This proves that the protein contains no N-terminal mitochondrial targeting prepiece and that a targeting region must reside within the amino acid sequence of the mature protein. Images PMID:3012461

Deciphering the Biophysical Effects of Oxidizing Sulfur-Containing Amino Acids in Interferon-beta-1a using MS and HDX-MS

NASA Astrophysics Data System (ADS)

Houde, Damian J.; Bou-Assaf, George M.; Berkowitz, Steven A.

2017-05-01

Introduction of a chemical change to one or more amino acids in a protein's polypeptide chain can result in various effects on its higher-order structure (HOS) and biophysical behavior (or properties). These effects range from no detectable change to significant structural or conformational alteration that can greatly affect the protein's biophysical properties and its resulting biological function. The ability to reliably detect the absence or presence of such changes is essential to understanding the structure-function relationship in a protein and in the successful commercial development of protein-based drugs (biopharmaceuticals). In this paper, we focus our attention on the latter by specifically elucidating the impact of oxidation on the HOS, structural dynamics, and biophysical properties of interferon beta-1a (IFNβ-1a). Oxidation is a common biochemical modification that occurs in many biopharmaceuticals, specifically in two naturally-occurring sulfur-containing amino acids, methionine and cysteine. To carry out this work, we used combinations of hydrogen peroxide and pH to differentially oxidize IFNβ-1a (to focus on only methionine oxidation versus methionine and cysteine oxidation). We then employed several analytical and biophysical techniques to acquire information about the differential impact of these two oxidation scenarios on IFNβ-1a. In particular, the use of MS-based techniques, especially HDX-MS, play a dominant role in revealing the differential effects.

Changes in N-acetylglutamate are involved in regulating urea synthesis in rats given a low gluten diet supplemented with L-lysine, L-methinone and L-threonine.

PubMed

Tujioka, Kazuyo; Tuchiya, Tamami; Shi, Xianglan; Ohsumi, Miho; Hayase, Kazutoshi; Yokogoshi, Hidehiko

2009-01-01

We have shown that urinary urea excretion decreased in rats fed a low gluten diet supplemented with dietary limiting amino acids. The purpose of present study was to determine whether the addition of dietary limiting amino acids to a low gluten diet affected the synthesis and degradation of N-acetylglutamate and regulated urea synthesis. Experiments were done on two groups of rats, given diets containing 10% gluten or 10% gluten+0.5% L-lysine, 0.2% L-threonine and 0.2% L-methionine for 10 d. The urinary excretion of urea, and the liver concentration of N-acetylglutamate, and the liver activity of N-acetylglutamate synthetase decreased with the addition of dietary L-lysine, L-threonine and L-methionine. N-Acetylglutamate concentration in the liver was closely correlated with the N-acetylglutamate synthetase activity in the liver and excretion of urea. The greater degradation of N-acetylglutamate was observed in the group fed the 10% gluten+L-lysine, L-threonine and L-methionine. The hepatic concentration of glutamate and plasma concentration of arginine were not related to the N-acetylglutamate concentration in the liver. These results suggest that the addition of limiting amino acids to the low gluten diet controls the synthesis and degradation of N-acetylglutamate in the liver and lowers urea synthesis.

Efficacy of DL-methionine hydroxy analogue-free acid in comparison to DL-methionine in growing male white Pekin ducks.

PubMed

Kluge, H; Gessner, D K; Herzog, E; Eder, K

2016-03-01

The present study was performed to assess the bioefficacy of DL-methionine hydroxy analogue-free acid (MHA) in comparison to DL-methionine (DLM) as sources of methionine for growing male white Pekin ducks in the first 3 wk of life. For this aim, 580 1-day-old male ducks were allocated into 12 treatment groups and received a basal diet that contained 0.29% of methionine, 0.34% of cysteine and 0.63% of total sulphur containing amino acids or the same diet supplemented with either DLM or MHA in amounts to supply 0.05, 0.10, 0.15, 0.20, and 0.25% of methionine equivalents. Ducks fed the control diet without methionine supplement had the lowest final body weights, daily body weight gains and feed intake among all groups. Supplementation of methionine improved final body weights and daily body weight gains in a dose dependent-manner. There was, however, no significant effect of the source of methionine on all of the performance responses. Evaluation of the data of daily body weight gains with an exponential model of regression revealed a nearly identical efficacy (slope of the curves) of both compounds for growth (DLM = 100%, MHA = 101%). According to the exponential model of regression, 95% of the maximum values of daily body weight gain were reached at methionine supplementary levels of 0.080% and 0.079% for DLM and MHA, respectively. Overall, the present study indicates that MHA and DLM have a similar efficacy as sources of methionine for growing ducks. It is moreover shown that dietary methionine concentrations of 0.37% are required to reach 95% of the maximum of daily body weight gains in ducks during the first 3 wk of life. © 2015 Poultry Science Association Inc.

The regulation of sulphurated amino acid junctions: fact or fiction in the field of inflammation?

PubMed

Santangelo, F

2002-01-01

The diet of industrialised countries is usually rich in amino acids, which are in part used as a source of calories. However, metabolic alterations are observed in diseased patients and a preferential retention of Sulphurated Amino Acids (SAA) occurs during the inflammatory response. Moreover, it has been demonstrated in a model of an acute sepsis phase of rats that the metabolism of Cysteine is modified. The liver converts Cysteine at a different ratio of Sulphate to Taurine (Tau) i.e. the sulphate production decreases while the Tau conversion increases. The Glutathione (GSH) concentration is greater in the liver, kidneys and other organs and the Cysteine incorporation into proteins is higher in the spleen, lungs and plasma (Acute Phase Proteins) while the Albumin level decreases. The pro-inflammatory cytokines such as Interleukin-1, Interleukin-6 and TNF- alpha are the main initiators that alter protein and amino acid metabolism. Another important phenomenon is the impairment of Methionine conversion to Cysteine during stress. For example, premature infants or AIDS patients are capable of synthesizing Cysteine from Methionine at a much lower rate. Thus, the metabolic flow through the trans-sulphuration path may be inadequate to meet the Cysteine demand under critical conditions. In this complex picture, an SAA supply may contribute to an immune system regulation.

Solubility calculations of branched and linear amino acids using lattice cluster theory

NASA Astrophysics Data System (ADS)

Fischlschweiger, Michael; Enders, Sabine; Zeiner, Tim

2014-09-01

In this work, the activity coefficients and the solubility of amino acids in water were calculated using the lattice cluster theory (LCT) combined with the extended chemical association lattice model allowing self-association as well as cross-association. This permits the study of the influence of the amino acids structure on the thermodynamic properties for the first time. By the used model, the activity coefficient and solubilities of the investigated fourteen amino acids (glycine, alanine, γ-aminobutyric acid, dl-valine, dl-threonine, dl-methionine, l-leucine, l-glutamic acid, l-proline, hydroxyproline, histidine, l-arginine, α-amino valeric acid) could be described in good accordance with experimental data. In the case of different α-amino acids, but different hydrocarbon chains, the same interaction energy parameter can be used within the LCT. All studied amino acids could be modelled using the same parameter for the description of the amino acid association properties. The formed cross-associates contain more amino acids than expressed by the overall mole fraction of the solution. Moreover, the composition of the cross-associates depends on temperature, where the amount of amino acids increases with increasing temperature.

The effect of amino acids on the intestinal absorption of immunoglobulins in the neonatal rat

PubMed Central

Bamford, D. R.; Donnelly, H.

1974-01-01

An in vitro preparation of 10-day-old rat intestine was used to examine the absorption of a number of amino acids and immunoglobulins. Evidence was obtained for the active absorption of alanine, leucine, methionine, histidine and lysine, but not for aspartic acid. A selective absorption of the homologous molecule was found in experiments where 131I-labelled rat and bovine IgG were presented to the ileum in 10-minute incubations. The greater uptake of rat IgG was unrelated to the relative rates of catabolism of the two molecules. Although the uptake of rat IgG was unaffected by 100 mM concentrations of neutral and acidic amino acids, the basic amino acids arginine and lysine significantly stimulated uptake. PMID:4854740

Effect of methyl jasmonate application to grapevine leaves on grape amino acid content.

PubMed

Garde-Cerdán, Teresa; Portu, Javier; López, Rosa; Santamaría, Pilar

2016-07-15

Over the last few years, considerable attention has been paid to the application of elicitors to vineyard. However, research about the effect of elicitors on grape amino acid content is scarce. Therefore, the aim of this study was to evaluate the influence of foliar application of methyl jasmonate on must amino acid content. Results revealed that total amino acid content was not modified by the application of methyl jasmonate. However, the individual content of certain amino acids was increased as consequence of methyl jasmonate foliar application, i.e., histidine, serine, tryptophan, phenylalanine, tyrosine, asparagine, methionine, and lysine. Among them, phenylalanine content was considerably increased; this amino acid is precursor of phenolic and aromatic compounds. In conclusion, foliar application of methyl jasmonate improved must nitrogen composition. This finding suggests that methyl jasmonate treatment might be conducive to obtain wines of higher quality since must amino acid composition could affect the wine volatile composition and the fermentation kinetics. Copyright © 2016 Elsevier Ltd. All rights reserved.

The metabolic burden of creatine synthesis.

PubMed

Brosnan, John T; da Silva, Robin P; Brosnan, Margaret E

2011-05-01

Creatine synthesis is required in adult animals to replace creatine that is spontaneously converted to creatinine and excreted in the urine. Additionally, in growing animals it is necessary to provide creatine to the expanding tissue mass. Creatine synthesis requires three amino acids: glycine, methionine and arginine, and three enzymes: L-arginine:glycine amidinotransferase (AGAT), methionine adenosyltransferase (MAT) and guanidinoacetate methyltransferase (GAMT). The entire glycine molecule is consumed in creatine synthesis but only the methyl and amidino groups, respectively, from methionine and arginine. Creatinine loss averages approximately 2 g (14.6 mmol) for 70 kg males in the 20- to 39-year age group. Creatinine loss is lower in females and in older age groups because of lower muscle mass. Approximately half of this creatine lost to creatinine can be replaced, in omnivorous individuals, by dietary creatine. However, since dietary creatine is only provided in animal products, principally in meat and fish, virtually all of the creatine loss in vegetarians must be replaced via endogenous synthesis. Creatine synthesis does not appear to place a major burden on glycine metabolism in adults since this amino acid is readily synthesized. However, creatine synthesis does account for approximately 40% of all of the labile methyl groups provided by S-adenosylmethionine (SAM) and, as such, places an appreciable burden on the provision of such methyl groups, either from the diet or via de novo methylneogenesis. Creatine synthesis consumes some 20-30% of arginine's amidino groups, whether provided in the diet or synthesized within the body. Creatine synthesis is, therefore, a quantitatively major pathway in amino acid metabolism and imposes an appreciable burden on the metabolism of methionine and of arginine.

Parsing the life-shortening effects of dietary protein: effects of individual amino acids

PubMed Central

Bouchebti, Sofia; Bazazi, Sepideh; Le Hesran, Sophie; Puga, Camille; Latil, Gérard; Simpson, Stephen J.

2017-01-01

High-protein diets shorten lifespan in many organisms. Is it because protein digestion is energetically costly or because the final products (the amino acids) are harmful? To answer this question while circumventing the life-history trade-off between reproduction and longevity, we fed sterile ant workers on diets based on whole proteins or free amino acids. We found that (i) free amino acids shortened lifespan even more than proteins; (ii) the higher the amino acid-to-carbohydrate ratio, the shorter ants lived and the lower their lipid reserves; (iii) for the same amino acid-to-carbohydrate ratio, ants eating free amino acids had more lipid reserves than those eating whole proteins; and (iv) on whole protein diets, ants seem to regulate food intake by prioritizing sugar, while on free amino acid diets, they seem to prioritize amino acids. To test the effect of the amino acid profile, we tested diets containing proportions of each amino acid that matched the ant's exome; surprisingly, longevity was unaffected by this change. We further tested diets with all amino acids under-represented except one, finding that methionine, serine, threonine and phenylalanine are especially harmful. All together, our results show certain amino acids are key elements behind the high-protein diet reduction in lifespan. PMID:28053059

Parsing the life-shortening effects of dietary protein: effects of individual amino acids.

PubMed

Arganda, Sara; Bouchebti, Sofia; Bazazi, Sepideh; Le Hesran, Sophie; Puga, Camille; Latil, Gérard; Simpson, Stephen J; Dussutour, Audrey

2017-01-11

High-protein diets shorten lifespan in many organisms. Is it because protein digestion is energetically costly or because the final products (the amino acids) are harmful? To answer this question while circumventing the life-history trade-off between reproduction and longevity, we fed sterile ant workers on diets based on whole proteins or free amino acids. We found that (i) free amino acids shortened lifespan even more than proteins; (ii) the higher the amino acid-to-carbohydrate ratio, the shorter ants lived and the lower their lipid reserves; (iii) for the same amino acid-to-carbohydrate ratio, ants eating free amino acids had more lipid reserves than those eating whole proteins; and (iv) on whole protein diets, ants seem to regulate food intake by prioritizing sugar, while on free amino acid diets, they seem to prioritize amino acids. To test the effect of the amino acid profile, we tested diets containing proportions of each amino acid that matched the ant's exome; surprisingly, longevity was unaffected by this change. We further tested diets with all amino acids under-represented except one, finding that methionine, serine, threonine and phenylalanine are especially harmful. All together, our results show certain amino acids are key elements behind the high-protein diet reduction in lifespan. © 2017 The Author(s).

Oxidation of methionine - is it limiting the diagnostic properties of 99mTc-labeled Exendin-4, a Glucagon-Like Peptide-1 receptor agonist?

PubMed

Janota, Barbara; Karczmarczyk, Urszula; Laszuk, Ewa; Garnuszek, Piotr; Mikołajczak, Renata

2016-01-01

Preliminary clinical evaluation of 99mTc-EDDA/HYNIC-Met14-Exendin-4 showed that the complex offers new diagnostic possibilities for insulinoma and MTC. Exendin-4 contains methionine at position 14 in the amino acid chain, which may be oxidized to methionine sulfoxide and, from the pharmaceutical point of view, the oxidized moiety becomes an undesired impurity in the final radioactive preparation. Therefore, the aim of this study was to investigate the influence of commonly used methods to eliminate the effect of methionine oxidation in peptides, i.e. the replacement of methionine by norleucine (Nle) and the addition of L-methionine, on the in vitro stability and the biodistribution. 99mTc-EDDA/HYNIC-Met14-Exendin-4, 99mTc-EDDA/HYNIC-Nle14-Exendin-4, 99mTc-EDDA/HYNIC-Met14-Ex-endin-4 with the addition of L-methionine and an oxidized form of Exendin-4, i.e. 99mTc-EDDA/HYNIC-Met14(ox)-Exendin-4 were compared in vivo with 68Ga-NODAGA-Nle14-Exendin-4 in normal Wistar rats. The stability and lipophilicity were determined in vitro. Biodistribution studies confirmed the specific uptake of all tested complexes in the GLP-1 positive organs: lungs, pancreas and stomach. The uptake of 99mTc-EDDA/HYNIC-Met14-Exendin-4 with the addition of L-methionine and for 68Ga-NODAGA-Nle14-Exendin-4 at 1h p.i. was around 2-fold higher than that of 99mTc-EDDA/HYNIC-Met14-Exendin-4 and 99mTc-EDDA/HYNIC-Nle14-Exendin-4. Although the substitution of methionine by norleucine in the HYNIC-Exendin-4 did not result in improved bio-distribution, the use of L-methionine, as the excipient that inhibits the oxidation of methionine in the peptide chain resulted in higher lung/blood and stomach/blood uptake ratios. Our results confirmed that methionine at position 14 of amino acid chain of Exendin-4 plays an important role in the interaction with GLP-1 receptor positive tissue.

Mechanisms of spectral tuning in the RH2 pigments of Tokay gecko and American chameleon

PubMed Central

Takenaka, Naomi; Yokoyama, Shozo

2009-01-01

At present, molecular bases of spectral tuning in rhodopsin-like (RH2) pigments are not well understood. Here, we have constructed the RH2 pigments of nocturnal Tokay gecko (Gekko gekko) and diurnal American chameleon (Anolis carolinensis) as well as chimeras between them. The RH2 pigments of the gecko and chameleon reconstituted with 11-cis-retinal had the wavelengths of maximal absorption (λmax’s) of 467 and 496 nm, respectively. Chimeric pigment analyses indicated that 76–86%, 14–24%, and 10% of the spectral difference between them could be explained by amino acid differences in transmembrane (TM) helices I~IV, V~VII, and amino acid interactions between the two segments, respectively. Evolutionary and mutagenesis analyses revealed that the λmax’s of the gecko and chameleon pigments diverged from each other not only by S49A (serine to alanine replacement at residue 49), S49F (serine to phenylalanine), L52M (leucine to methionine), D83N (aspartic acid to asparagine), M86T (methionine to thereonine), and T97A (threonine to alanine) but also by other amino acid replacements that cause minor λmax-shifts individually. PMID:17590287

Effect of aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing amino acids on Leishmania spp. chemotaxis.

PubMed

Diaz, E; Zacarias, A K; Pérez, S; Vanegas, O; Köhidai, L; Padrón-Nieves, M; Ponte-Sucre, A

2015-11-01

In the sand-fly mid gut, Leishmania promastigotes are exposed to acute changes in nutrients, e.g. amino acids (AAs). These metabolites are the main energy sources for the parasite, crucial for its differentiation and motility. We analysed the migratory behaviour and morphological changes produced by aliphatic, monocarboxylic, dicarboxylic, heterocyclic and sulphur-containing AAs in Leishmania amazonensis and Leishmania braziliensis and demonstrated that L-methionine (10-12 m), L-tryptophan (10-11 m), L-glutamine and L-glutamic acid (10-6 m), induced positive chemotactic responses, while L-alanine (10-7 m), L-methionine (10-11 and 10-7 m), L-tryptophan (10-11 m), L-glutamine (10-12 m) and L-glutamic acid (10-9 m) induced negative chemotactic responses. L-proline and L-cysteine did not change the migratory potential of Leishmania. The flagellum length of L. braziliensis, but not of L. amazonensis, decreased when incubated in hyperosmotic conditions. However, chemo-repellent concentrations of L-alanine (Hypo-/hyper-osmotic conditions) and L-glutamic acid (hypo-osmotic conditions) decreased L. braziliensis flagellum length and L-methionine (10-11 m, hypo-/hyper-osmotic conditions) decreased L. amazonensis flagellum length. This chemotactic responsiveness suggests that Leishmania discriminate between slight concentration differences of small and structurally closely related molecules and indicates that besides their metabolic effects, AAs play key roles linked to sensory mechanisms that might determine the parasite's behaviour.

Diet quality influences isotopic discrimination among amino acids in an aquatic vertebrate

PubMed Central

Chikaraishi, Yoshito; Steffan, Shawn A; Takano, Yoshinori; Ohkouchi, Naohiko

2015-01-01

Stable nitrogen isotopic composition of amino acids (δ15NAA) has recently been employed as a powerful tool in ecological food web studies, particularly for estimating the trophic position (TP) of animal species in food webs. However, the validity of these estimates depends on the consistency of the trophic discrimination factor (TDF; - Δδ15NAA at each shift of trophic level) among a suite of amino acids within the tissues of consumer species. In this study, we determined the TDF values of amino acids in tadpoles (the Japanese toad, Bufo japonicus) reared exclusively on one of three diets that differed in nutritional quality. The diets were commercial fish-food pellets (plant and animal biomass), bloodworms (animal biomass), and boiled white rice (plant carbohydrate), representing a balanced, protein-rich, and protein-poor diet, respectively. The TDF values of two “source amino acids” (Src-AAs), methionine and phenylalanine, were close to zero (0.3–0.5‰) among the three diets, typifying the values reported in the literature (∼0.5‰ and ∼0.4‰, respectively). However, TDF values of “trophic amino acids” (Tr-AAs) including alanine, valine, leucine, isoleucine, and glutamic acid varied by diet: for example, the glutamic acid TDF was similar to the standard value (∼8.0‰) when tadpoles were fed either the commercial pellets (8.0‰) or bloodworms (7.9‰), but when they were fed boiled rice, the TDF was significantly reduced (0.6‰). These results suggest that a profound lack of dietary protein may alter the TDF values of glutamic acid (and other Tr-AAs and glycine) within consumer species, but not the two Src-AAs (i.e., methionine and phenylalanine). Knowledge of how a nutritionally poor diet can influence the TDF of Tr- and Src-AAs will allow amino acid isotopic analyses to better estimate TP among free-roaming animals. PMID:26045955

Effect of methionine and lactic acid bacteria as aflatoxin binder on broiler performance

NASA Astrophysics Data System (ADS)

Istiqomah, Lusty; Damayanti, Ema; Julendra, Hardi; Suryani, Ade Erma; Sakti, Awistaros Angger; Anggraeni, Ayu Septi

2017-06-01

The use of aflatoxin binder product based amino acids, lacic acid bacteria, and natural product gived the opportunity to be an alternative biological decontamination of aflatoxins. A study was conducted to determine the efficacy of aflatoxin binder administration (amino acid methionine and lactic acid bacteria (Lactobacillus plantarum G7)) as feed additive on broiler performance. In this study, 75 Lohmann unsexed day old chicks were distributed randomly into 5 units of cages, each filled with 15 broilers. Five cages were assigned into 5 treatments groups and fed with feed contained aflatoxin. The treatments as follow: P1 (aflatoxin feed without aflatoxin binder), P3 (aflatoxin feed + 0.8% of methionine + 1% of LAB), P4 (aflatoxin feed + 1.2% of methionine + 1% of LAB), P5 (aflatoxin feed + 1% of LAB), and K0 (commercial feed). The measurement of aflatoxin content in feed was performed by Enzyme Linked Immunosorbent Assay method using AgraQuant® Total Aflatoxin Assay Romer Labs procedure. The experimental period was 35 days with feeding and drinking ad libitum. LAB was administered into drinking water, while methionine into feed. Vaccination program of Newcastle Disease (ND) was using active vaccine at 4 and 18 day old, while Infectious Bursal Disease (IBD) was given at 8 day old. Parameter of body weight was observed weekly, while feed consumption noted daily. The result showed that aflatoxin in feed for 35 days period did not significantly affect the body weight gain and feed conversion. The lowest percentage of organ damage at 21 day old was found in P5 treatment (55%), while at 35day old was found in P4 treatment (64%). It could be concluded that technological process of detoxifying aflatoxin could be applied in an attempt to reduce the effect on the toxicity of aflatoxin in poultry feed.

The choline requirement of broiler chicks during the seventh week of life.

PubMed

Molitoris, B A; Baker, D H

1976-01-01

Male crossbred chicks were used to quantify the choline requirement and choline-sparing value of methionine and betaine for broiler chicks during the seventh week of life. The sulfur amino acid (SAA) requirement of male and female chicks was also determined. In all assays a crystalline amino acid diet containing 14.9% protein equivalent and 3400 kcal. M.E./kg, was employed. Increasing increments (0.08%) of SAA (equal mixture of DL-methionine and L-cystine) were fed from 0.38 to 0.70% of the diet. Least squares analysis indicated SAA requirements for maximal weight gain of 0.61 and 0.62% of the diet for males and females, respectively. The choline requirement was determined by feeding six levels of choline in the presence of 0.62% SAA. Gain but not gain/feed responded linearly to choline addition. Least squares analysis of gain indicated a dietary choline requirement of 358 p.p.m. of 30.6 mg./day. The choline-replacement value of methionine and betaine was found to be minimal.

Altered peripheral amino acid profile indicate a systemic impact of active celiac disease and a possible role of amino acids in disease pathogenesis.

PubMed

Torinsson Naluai, Åsa; Saadat Vafa, Ladan; Gudjonsdottir, Audur H; Arnell, Henrik; Browaldh, Lars; Nilsson, Staffan; Agardh, Daniel

2018-01-01

We have previously performed a Genome Wide Association and linkage study that indicated a new disease triggering mechanism involving amino acid metabolism and nutrient sensing signaling pathways. The aim of this study was to investigate if plasma amino acid levels differed among children with celiac disease compared with disease controls. Fasting plasma samples from 141 children with celiac disease and 129 non-celiac disease controls, were analyzed for amino acid levels by liquid chromatography-tandem mass spectrometry (LC/MS). A general linear model using age and experimental effects as covariates was used to compare amino acid levels between children with a diagnosis of celiac disease and controls. Seven out of twenty-three analyzed amino acids were elevated in children with celiac disease compared with controls (tryptophan, taurine, glutamic acid, proline, ornithine, alanine and methionine). The significance of the individual amino acids do not survive multiple correction, however, multivariate analyses of the amino acid profile showed significantly altered amino acid levels in children with celiac disease overall and after correction for age, sex and experimental effects (p = 8.4 × 10-8). These findings support the idea that amino acids could influence systemic inflammation and play a possible role in disease pathogenesis.

THE NUTRITION OF ANIMAL TISSUES CULTIVATED IN VITRO

PubMed Central

Morgan, Joseph F.; Morton, Helen J.

1957-01-01

1. The amino acid requirements of freshly explanted chick embryonic heart tissues cultivated in completely synthetic media have been determined, employing a nutritional depletion technique. Arginine, histidine, lysine, tyrosine, tryptophan, phenylalanine, cystine, methionine, threonine, leucine, and valine were found to be essential. Serine, isoleucine, glycine, and glutamine were found to be non-essential. Glutamic acid, aspartic acid, α-alanine, proline, and hydroxyproline were found to be inhibitory in this test system. 2. A total amino acid level of approximately 100 mg. per cent was found to be optimal and DL-amino acids were found to be non-toxic, unless used in high concentrations. 3. A comparison has been made of the amino acid requirements of various types of tissue cultures, of the chick, and of man and certain differences in these requirements have been discussed. PMID:13438897

Regulation of cell function by methionine oxidation and reduction

PubMed Central

Hoshi, Toshinori; Heinemann, Stefan H

2001-01-01

Reactive oxygen species (ROS) are generated during normal cellular activity and may exist in excess in some pathophysiological conditions, such as inflammation or reperfusion injury. These molecules oxidize a variety of cellular constituents, but sulfur-containing amino acid residues are especially susceptible. While reversible cysteine oxidation and reduction is part of well-established signalling systems, the oxidation and the enzymatically catalysed reduction of methionine is just emerging as a novel molecular mechanism for cellular regulation. Here we discuss how the oxidation of methionine to methionine sulfoxide in signalling proteins such as ion channels affects the function of these target proteins. Methionine sulfoxide reductase, which reduces methionine sulfoxide to methionine in a thioredoxin-dependent manner, is therefore not only an enzyme important for the repair of age- or degenerative disease-related protein modifications. It is also a potential missing link in the post-translational modification cycle involved in the specific oxidation and reduction of methionine residues in cellular signalling proteins, which may give rise to activity-dependent plastic changes in cellular excitability. PMID:11179387

L-Methionine Production.

PubMed

Shim, Jihyun; Shin, Yonguk; Lee, Imsang; Kim, So Young

L-Methionine has been used in various industrial applications such as the production of feed and food additives and has been used as a raw material for medical supplies and drugs. It functions not only as an essential amino acid but also as a physiological effector, for example, by inhibiting fat accumulation and enhancing immune response. Producing methionine from fermentation is beneficial in that microorganisms can produce L-methionine selectively using eco-sustainable processes. Nevertheless, the fermentative method has not been used on an industrial scale because it is not competitive economically compared with chemical synthesis methods. Presented are efforts to develop suitable strains, engineered enzymes, and alternative process of producing L-methionine that overcomes problems of conventional fermentation methods. One of the alternative processes is a two-step process in which the L-methionine precursor is produced by fermentation and then converted to L-methionine by enzymes. Directed efforts toward strain development and enhanced enzyme engineering will advance industrial production of L-methionine based on fermentation.

L-leucine, L-methionine, and L-phenylalanine share a Na(+)/K (+)-dependent amino acid transporter in shrimp hepatopancreas.

PubMed

Duka, Ada; Ahearn, Gregory A

2013-08-01

Hepatopancreatic brush border membrane vesicles (BBMV), made from Atlantic White shrimp (Litopenaeus setiferus), were used to characterize the transport properties of (3)H-L-leucine influx by these membrane systems and how other essential amino acids and the cations, sodium and potassium, interact with this transport system. (3)H-L-leucine uptake by BBMV was pH-sensitive and occurred against transient transmembrane concentration gradients in both Na(+)- and K(+)-containing incubation media, suggesting that either cation was capable of providing a driving force for amino acid accumulation. (3)H-L-leucine uptake in NaCl or KCl media were each three times greater in acidic pH (pH 5.5) than in alkaline pH (pH 8.5). The essential amino acid, L-methionine, at 20 mM significantly (p < 0.0001) inhibited the 2-min uptakes of 1 mM (3)H-L-leucine in both Na(+)- and K(+)-containing incubation media. The residual (3)H-L-leucine uptake in the two media were significantly greater than zero (p < 0.001), but not significantly different from each other (p > 0.05) and may represent an L-methionine- and cation-independent transport system. (3)H-L-leucine influxes in both NaCl and KCl incubation media were hyperbolic functions of [L-leucine], following the carrier-mediated Michaelis-Menten equation. In NaCl, (3)H-L-leucine influx displayed a low apparent K M (high affinity) and low apparent J max, while in KCl the transport exhibited a high apparent K M (low affinity) and high apparent J max. L-methionine or L-phenylalanine (7 and 20 mM) were competitive inhibitors of (3)H-L-leucine influxes in both NaCl and KCl media, producing a significant (p < 0.01) increase in (3)H-L-leucine influx K M, but no significant response in (3)H-L-leucine influx J max. Potassium was a competitive inhibitor of sodium co-transport with (3)H-L-leucine, significantly (p < 0.01) increasing (3)H-L-leucine influx K M in the presence of sodium, but having negligible effect on (3)H-L-leucine influx J max in the same medium. These results suggest that shrimp BBMV transport (3)H-L-leucine by a single L-methionine- and L-phenylalanine-shared carrier system that is enhanced by acidic pH and can be stimulated by either Na(+) or K(+) acting as co-transport drivers binding to shared activator sites.

Quantification of sulphur amino acids by ultra-high performance liquid chromatography in aquatic invertebrates.

PubMed

Thera, Jennifer C; Kidd, Karen A; Dodge-Lynch, M Elaine; Bertolo, Robert F

2017-12-15

We examined the performance of an ultra-high performance liquid chromatography method to quantify protein-bound sulphur amino acids in zooplankton. Both cysteic acid and methionine sulfone were linear from 5 to 250 pmol (r 2  = 0.99), with a method detection limit of 13 pmol and 9 pmol, respectively. Although there was no matrix effect on linearity, adjacent peaks and co-eluting noise from the invertebrate proteins increased the detection limits when compared to common standards. Overall, performance characteristics were reproducible and accurate, and provide a means for quantifying sulphur amino acids in aquatic invertebrates, an understudied group. Copyright © 2017 Elsevier Inc. All rights reserved.

Response of growing goslings to dietary supplementation with methionine and betaine.

PubMed

Yang, Z; Wang, Z Y; Yang, H M; Zhao, F Z; Kong, L L

2016-12-01

An experiment with a 2 × 3 factorial design with two concentrations of dietary betaine (0 and 600 mg/kg) and three dietary concentrations of methionine (0, 600 and 1200 mg/kg) was conducted using goslings to estimate growth, nutrient utilisation and digestibility of amino acids from 21 to 70 d of age. Three hundred geese were randomised at 18 d of age into 6 groups with 5 replicates per treatment and 10 geese per replicate. Increasing dietary concentrations of methionine gave a linear increase in body weight and average daily gain. The coefficient of crude fat retention increased as dietary methionine increased and there was a significant non-linear response to increasing dietary methionine. Similarly, increasing supplemental methionine gave linear increases in the digestibility of methionine and cysteine. The results of this study indicated that optimal dietary supplementation of methionine could increase growth performance and methionine and cysteine utilisation in growing goslings. Betaine supplementation had no apparent sparing effect on methionine needs for growth performance, but did improve the apparent cysteine digestibility.

The importance of transmethylation reactions to methionine metabolism in sheep: effects of supplementation with creatine and choline.

PubMed

Lobley, G E; Connell, A; Revell, D

1996-01-01

The influence of administering the methylated products choline and creatine on methionine irreversible-loss rate (ILR) and recycling from homocysteine has been investigated in sheep fed close to energy and N equilibrium. Two methods to estimate methionine recycling were compared. The first involved [U-13C]methionine infused as part of a labelled amino acid mixture obtained from hydrolysed algal protein. In this approach the isotope dilution of methionine with all five C atoms labelled (m + 5) will represent the ILR which does not recycle through homocysteine, while that which includes molecules with C-1-C-4 labelled will allow for loss of the labelled methyl (5)-C atom and replacement by an unlabelled moiety in the remethylation of homocysteine. The second method involved a combined infusion of [1-13C]- and [S-methyl-2H3]methionine. These two approaches gave similar data for methionine ILR which does not include label recycled to the amino acid from homocysteine but differed for recycled methionine fluxes. Consequently the two procedures differed in the calculated extent of homocysteine methylation under control conditions (6 v. 28%). These extents of remethylation are within the range observed for the fed human subject, despite the fact that fewer dietary methyl groups are available for the ruminant. Using combined data from the infusions, significant depression of methionine recycling occurred in blood (P < 0.05), with a similar trend for plasma (P = 0.077), when choline plus creatine were infused. Wool growth, assessed by intradermal injection of [35S]cysteine, was not altered by supplementation with the methylated products. From changes in the label pattern of free methionine in aortal, hepatic portal and hepatic venous blood during U-13C-labelled algal hydrolysate infusion, the major sites of homocysteine remethylation appear to be the portal-drained viscera and the liver. This was confirmed by analysis of free methionine enrichments in various tissues following dual infusion of [1-13C]- and [S-methyl-2H3]methionine, with the greatest activities occurring in rumen, jejunum and liver. Of the non-splanchnic tissues examined, only kidney exhibited substantial methionine cycling; none was detected in muscle, heart, lung and skin. The implications of methyl group provision under net production conditions are discussed.

IRIS TOXICOLOGICAL REVIEW AND SUMMARY DOCUMENTS FOR ACROLEIN (EXTERNAL REVIEW DRAFT)

EPA Science Inventory

Acrolein is a colorless to yellowish flammable liquid with a disagreeable, choking odor. The principal use of acrolein is as an intermediate in the synthesis of acrylic acid, which is used to make acrylates, and of DL-methionine, an essential amino acid used as an animal feed su...

Molecular Characteristics of Multicorn, a New Large Proteolytic Assembly and Potential Anti-Cancer Drug Target, in Human Breast Cancer Cells

DTIC Science & Technology

2005-05-01

modifications: peptide N-terminal glutamine to pyroglutamic transformation, oxidation of methionine, acetylation of protein N-terminus, and...or identical with human tripeptidyl peptidase II (TPPII) with a sequence of 1249 amino acids , accession number CAH72179, GI:55661755, derived from the...34In- Gel" Digestion Procedure for the Micropreparation of Internal Protein Fragments for Amino Acid Sequencing. Anal. Biochem., 224, 451-455. Osmulski

Effects of Local Delivery of d-amino Acids from Biofilm-dispersive Scaffolds on Infection in Contaminated Rat Segmental Defects

DTIC Science & Technology

2013-07-05

and L-isomers of amino acids (free base form), including alanine, isoleucine, leucine, methionine, phenylalanine , proline, tryptophan, tyrosine, and...lactide (T6C3G1L900) were synthesized using published techniques [33,34]. Appropriate amounts of dried glycerol and ε-caprolactone, glycolide, DL ...Hubbell JA. Rapidly degraded terpolymers of dl -lactide, glyco- lide, and epsilon-caprolactone with increased hydrophilicity by copolymeri- zation with

Simultaneous quantification of arginine, alanine, methionine and cysteine amino acids in supplements using a novel bioelectro-nanosensor based on CdSe quantum dot/modified carbon nanotube hollow fiber pencil graphite electrode via Taguchi method.

PubMed

Hooshmand, Sara; Es'haghi, Zarrin

2017-11-30

A number of four amino acids have been simultaneously determined at CdSe quantum dot-modified/multi-walled carbon nanotube hollow fiber pencil graphite electrode in different bodybuilding supplements. CdSe quantum dots were synthesized and applied to construct a modified carbon nanotube hollow fiber pencil graphite electrode. FT-IR, TEM, XRD and EDAX methods were applied for characterization of the synthesized CdSe QDs. The electro-oxidation of arginine (Arg), alanine (Ala), methionine (Met) and cysteine (Cys) at the surface of the modified electrode was studied. Then the Taguchi's method was applied using MINITAB 17 software to find out the optimum conditions for the amino acids determination. Under the optimized conditions, the differential pulse (DP) voltammetric peak currents of Arg, Ala, Met and Cys increased linearly with their concentrations in the ranges of 0.287-33670μM and detection limits of 0.081, 0.158, 0.094 and 0.116μM were obtained for them, respectively. Satisfactory results were achieved for calibration and validation sets. The prepared modified electrode represents a very good resolution between the voltammetric peaks of the four amino acids which makes it suitable for the detection of each in presence of others in real samples. Copyright © 2017. Published by Elsevier B.V.

A novel amino acid analysis method using derivatization of multiple functional groups followed by liquid chromatography/tandem mass spectrometry.

PubMed

Sakaguchi, Yohei; Kinumi, Tomoya; Yamazaki, Taichi; Takatsu, Akiko

2015-03-21

We have developed a novel amino acid analysis method using derivatization of multiple functional groups (amino, carboxyl, and phenolic hydroxyl groups). The amino, carboxyl, and phenolic hydroxyl groups of the amino acids were derivatized with 1-bromobutane so that the hydrophobicities and basicities of the amino acids were improved. The derivatized amino acids, including amino group-modified amino acids, could be detected with high sensitivity using liquid chromatography/tandem mass spectrometry (LC-MS/MS). In this study, 17 amino acids obtained by hydrolyzing proteins and 4 amino group-modified amino acids found in the human body (N,N-dimethylglycine, N-formyl-L-methionine, L-pyroglutamic acid, and sarcosine) were selected as target compounds. The 21 derivatized amino acids could be separated using an octadecyl-silylated silica column within 20 min and simultaneously detected. The detection limits for the 21 amino acids were 5.4-91 fmol, and the calibration curves were linear over the range of 10-100 nmol L(-1) (r(2) > 0.9984) with good repeatability. A confirmatory experiment showed that our proposed method could be applied to the determination of a protein certified reference material using the analysis of 12 amino acids combined with isotope dilution mass spectrometry. Furthermore, the proposed method was successfully applied to a stable isotope-coded derivatization method using 1-bromobutane and 1-bromobutane-4,4,4-d3 for comparative analysis of amino acids in human serum.

Overexpression of serine acetlytransferase produced large increases in O-acetylserine and free cysteine in developing seeds of a grain legume

PubMed Central

Tabe, Linda; Wirtz, Markus; Molvig, Lisa; Droux, Michel; Hell, Ruediger

2010-01-01

There have been many attempts to increase concentrations of the nutritionally essential sulphur amino acids by modifying their biosynthetic pathway in leaves of transgenic plants. This report describes the first modification of cysteine biosyntheis in developing seeds; those of the grain legume, narrow leaf lupin (Lupinus angustifolius, L.). Expression in developing lupin embryos of a serine acetyltransferase (SAT) from Arabidopsis thaliana (AtSAT1 or AtSerat 2;1) was associated with increases of up to 5-fold in the concentrations of O-acetylserine (OAS), the immediate product of SAT, and up to 26-fold in free cysteine, resulting in some of the highest in vivo concentrations of these metabolites yet reported. Despite the dramatic changes in free cysteine in developing embryos of SAT overexpressers, concentrations of free methionine in developing embryos, and the total cysteine and methionine concentrations in mature seeds were not significantly altered. Pooled F2 seeds segregating for the SAT transgene and for a transgene encoding a methionine- and cysteine-rich sunflower seed storage protein also had increased OAS and free cysteine, but not free methionine, during development, and no increase in mature seed total sulphur amino acids compared with controls lacking SAT overexpression. The data support the view that the cysteine biosynthetic pathway is active in developing seeds, and indicate that SAT activity limits cysteine biosynthesis, but that cysteine supply is not limiting for methionine biosynthesis or for storage protein synthesis in maturing lupin embryos in conditions of adequate sulphur nutrition. OAS and free methionine, but not free cysteine, were implicated as signalling metabolites controlling expression of a gene for a cysteine-rich seed storage protein. PMID:19939888

Overexpression of serine acetlytransferase produced large increases in O-acetylserine and free cysteine in developing seeds of a grain legume.

PubMed

Tabe, Linda; Wirtz, Markus; Molvig, Lisa; Droux, Michel; Hell, Ruediger

2010-03-01

There have been many attempts to increase concentrations of the nutritionally essential sulphur amino acids by modifying their biosynthetic pathway in leaves of transgenic plants. This report describes the first modification of cysteine biosynthesis in developing seeds; those of the grain legume, narrow leaf lupin (Lupinus angustifolius, L.). Expression in developing lupin embryos of a serine acetyltransferase (SAT) from Arabidopsis thaliana (AtSAT1 or AtSerat 2;1) was associated with increases of up to 5-fold in the concentrations of O-acetylserine (OAS), the immediate product of SAT, and up to 26-fold in free cysteine, resulting in some of the highest in vivo concentrations of these metabolites yet reported. Despite the dramatic changes in free cysteine in developing embryos of SAT overexpressers, concentrations of free methionine in developing embryos, and the total cysteine and methionine concentrations in mature seeds were not significantly altered. Pooled F(2) seeds segregating for the SAT transgene and for a transgene encoding a methionine- and cysteine-rich sunflower seed storage protein also had increased OAS and free cysteine, but not free methionine, during development, and no increase in mature seed total sulphur amino acids compared with controls lacking SAT overexpression. The data support the view that the cysteine biosynthetic pathway is active in developing seeds, and indicate that SAT activity limits cysteine biosynthesis, but that cysteine supply is not limiting for methionine biosynthesis or for storage protein synthesis in maturing lupin embryos in conditions of adequate sulphur nutrition. OAS and free methionine, but not free cysteine, were implicated as signalling metabolites controlling expression of a gene for a cysteine-rich seed storage protein.

Enzymatic Synthesis of Amino Acids Endcapped Polycaprolactone: A Green Route Towards Functional Polyesters.

PubMed

Duchiron, Stéphane W; Pollet, Eric; Givry, Sébastien; Avérous, Luc

2018-01-30

ε-caprolactone (CL) has been enzymatically polymerized using α-amino acids based on sulfur (methionine and cysteine) as (co-)initiators and immobilized lipase B of Candida antarctica (CALB) as biocatalyst. In-depth characterizations allowed determining the corresponding involved mechanisms and the polymers thermal properties. Two synthetic strategies were tested, a first one with direct polymerization of CL with the native amino acids and a second one involving the use of an amino acid with protected functional groups. The first route showed that mainly polycaprolactone (PCL) homopolymer could be obtained and highlighted the lack of reactivity of the unmodified amino acids due to poor solubility and affinity with the lipase active site. The second strategy based on protected cysteine showed higher monomer conversion, with the amino acids acting as (co-)initiators, but their insertion along the PCL chains remained limited to chain endcapping. These results thus showed the possibility to synthesize enzymatically polycaprolactone-based chains bearing amino acids units. Such cysteine endcapped PCL materials could then find application in the biomedical field. Indeed, subsequent functionalization of these polyesters with drugs or bioactive molecules can be obtained, by derivatization of the amino acids, after removal of the protecting group.

Nutritional and medicinal aspects of D-amino acids.

PubMed

Friedman, Mendel; Levin, Carol E

2012-05-01

This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.

Sulfur deficiency changes mycosporine-like amino acid (MAA) composition of Anabaena variabilis PCC 7937: a possible role of sulfur in MAA bioconversion.

PubMed

Singh, Shailendra P; Klisch, Manfred; Sinha, Rajeshwar P; Häder, Donat-Peter

2010-01-01

In the present investigation we show for the first time that bioconversion of a primary mycosporine-like amino acid (MAA) into a secondary MAA is regulated by sulfur deficiency in the cyanobacterium Anabaena variabilis PCC 7937. This cyanobacterium synthesizes the primary MAA shinorine (RT = 2.2 min, lambda(max) = 334 nm) under normal conditions (PAR + UV-A + UV-B); however, under sulfur deficiency, a secondary MAA palythine-serine (RT = 3.9 min, lambda(max) = 320 nm) appears. Addition of methionine to sulfur-deficient cultures resulted in the disappearance of palythine-serine, suggesting the role of primary MAAs under sulfur deficiency in recycling of methionine by donating the methyl group from the glycine subunit of shinorine to tetrahydrofolate to regenerate the methionine from homocysteine. This is also the first report for the synthesis of palythine-serine by cyanobacteria which has so far been reported only from corals. Addition of methionine also affected the conversion of mycosporine-glycine into shinorine, consequently, resulted in the appearance of mycosporine-glycine (RT = 3.6 min, lambda(max) = 310 nm). Our results also suggest that palythine-serine is synthesized from shinorine. Based on these results we propose that glycine decarboxylase is the potential enzyme that catalyzes the bioconversion of shinorine to palythine-serine by decarboxylation and demethylation of the glycine unit of shinorine.

Methionine and Choline Supply during the Periparturient Period Alter Plasma Amino Acid and One-Carbon Metabolism Profiles to Various Extents: Potential Role in Hepatic Metabolism and Antioxidant Status.

PubMed

Zhou, Zheng; Vailati-Riboni, Mario; Luchini, Daniel N; Loor, Juan J

2016-12-29

The objective of this study was to profile plasma amino acids (AA) and derivatives of their metabolism during the periparturient period in response to supplemental rumen-protected methionine (MET) or rumen-protected choline (CHOL). Forty cows were fed from -21 through 30 days around parturition in a 2 × 2 factorial design a diet containing MET or CHOL. MET supply led to greater circulating methionine and proportion of methionine in the essential AA pool, total AA, and total sulfur-containing compounds. Lysine in total AA also was greater in these cows, indicating a better overall AA profile. Sulfur-containing compounds (cystathionine, cystine, homocystine, and taurine) were greater in MET-fed cows, indicating an enriched sulfur-containing compound pool due to enhanced transsulfuration activity. Circulating essential AA and total AA concentrations were greater in cows supplied MET due to greater lysine, arginine, tryptophan, threonine, proline, asparagine, alanine, and citrulline. In contrast, CHOL supply had no effect on essential AA or total AA, and only tryptophan and cystine were greater. Plasma 3-methylhistidine concentration was lower in response to CHOL supply, suggesting less tissue protein mobilization in these cows. Overall, the data revealed that enhanced periparturient supply of MET has positive effects on plasma AA profiles and overall antioxidant status.

Effects of transgenic expression of Brevibacterium linens methionine gamma lyase (MGL) on accumulation of Tylenchulus semipenetrans and key aminoacid contents in Carrizo citrange.

PubMed

Castillo, Elenor; Martinelli, Federico; Zakharov-Negre, Florence; Ebeler, Susan E; Buzo, Tom R; McKenry, Michael V; Dandekar, Abhaya M

2017-11-01

Carrizo transgenic plants overexpressing methionine-gamma-lyase produced dimethyl sulfide. The transgenic plants displayed more resistance to nematode attacks (Tylenculus semipenetrans) and may represent an innovative strategy for nematode control. Tylenchulus semipenetrans is a nematode pest of many citrus varieties that causes extensive damage to commercial crops worldwide. Carrizo citrange vr. (Citrus sinensis L. Usb × Poncirus trifoliate L. Raf) plants overexpressing Brevibacterium linens methionine-gamma-lyase (BlMGL) produced the sulfur volatile compound dimethyl sulfide (DMS). The aim of this work was to determine if transgenic citrus plants expressing BlMGL showed increased tolerance to T. semipenetrans infestation and to determine the effect on the content of key amino acids. While transgenic lines emitted dimethyl sulfide from leaves and roots, no sulfur-containing volatiles were detectable in wild-type Carrizo in the same tissues. Significant changes detected some key amino acids from leaves of transgenic plants such as aspartate, lysine, glycine, leucine and threonine with no changes in the amounts of methionine and α-ketobutyrate. In roots only glycine showed significant changes across all transgenic lines in comparison to wild-type plants. Transgenic plants expressing BlMGL and emitting DMS had less T. semipenetrans aggregation and more biomass than infected WT control plants, indicating that they may represent an innovative management alternative to pesticide/nematicide-based remedies.

Methionine and Choline Supply during the Periparturient Period Alter Plasma Amino Acid and One-Carbon Metabolism Profiles to Various Extents: Potential Role in Hepatic Metabolism and Antioxidant Status

PubMed Central

Zhou, Zheng; Vailati-Riboni, Mario; Luchini, Daniel N.; Loor, Juan J.

2016-01-01

The objective of this study was to profile plasma amino acids (AA) and derivatives of their metabolism during the periparturient period in response to supplemental rumen-protected methionine (MET) or rumen-protected choline (CHOL). Forty cows were fed from −21 through 30 days around parturition in a 2 × 2 factorial design a diet containing MET or CHOL. MET supply led to greater circulating methionine and proportion of methionine in the essential AA pool, total AA, and total sulfur-containing compounds. Lysine in total AA also was greater in these cows, indicating a better overall AA profile. Sulfur-containing compounds (cystathionine, cystine, homocystine, and taurine) were greater in MET-fed cows, indicating an enriched sulfur-containing compound pool due to enhanced transsulfuration activity. Circulating essential AA and total AA concentrations were greater in cows supplied MET due to greater lysine, arginine, tryptophan, threonine, proline, asparagine, alanine, and citrulline. In contrast, CHOL supply had no effect on essential AA or total AA, and only tryptophan and cystine were greater. Plasma 3-methylhistidine concentration was lower in response to CHOL supply, suggesting less tissue protein mobilization in these cows. Overall, the data revealed that enhanced periparturient supply of MET has positive effects on plasma AA profiles and overall antioxidant status. PMID:28036059

Natural variation in a single amino acid substitution underlies physiological responses to topoisomerase II poisons.

PubMed

Zdraljevic, Stefan; Strand, Christine; Seidel, Hannah S; Cook, Daniel E; Doench, John G; Andersen, Erik C

2017-07-01

Many chemotherapeutic drugs are differentially effective from one patient to the next. Understanding the causes of this variability is a critical step towards the development of personalized treatments and improvements to existing medications. Here, we investigate sensitivity to a group of anti-neoplastic drugs that target topoisomerase II using the model organism Caenorhabditis elegans. We show that wild strains of C. elegans vary in their sensitivity to these drugs, and we use an unbiased genetic approach to demonstrate that this natural variation is explained by a methionine-to-glutamine substitution in topoisomerase II (TOP-2). The presence of a non-polar methionine at this residue increases hydrophobic interactions between TOP-2 and its poison etoposide, as compared to a polar glutamine. We hypothesize that this stabilizing interaction results in increased genomic instability in strains that contain a methionine residue. The residue affected by this substitution is conserved from yeast to humans and is one of the few differences between the two human topoisomerase II isoforms (methionine in hTOPIIα and glutamine in hTOPIIβ). We go on to show that this amino acid difference between the two human topoisomerase isoforms influences cytotoxicity of topoisomerase II poisons in human cell lines. These results explain why hTOPIIα and hTOPIIβ are differentially affected by various poisons and demonstrate the utility of C. elegans in understanding the genetics of drug responses.

An unusual form of lipid linkage to the CD45 peptide

DOE Office of Scientific and Technical Information (OSTI.GOV)

Takeda, Akiko; Maizel, A.L.

1990-11-02

Some protein kinases and phosphatases are myristoylated on their amino terminus, which perhaps contributes to subcellular localization or regulation. Glycoprotein CD45, a hematopoietic tyrosine phosphatase, was examined for fatty acid content. The CD45 protein incorporated ({sup 3}H)myristate, but little ({sup 3}H)palmitate. The label was not metabolized and reincorporated into amino acids or saccharides, as revealed by peptide maps of CD45 labeled with ({sup 3}H)myristate, {sup 14}C-labeled amino acids, ({sup 35}S)methionine, or {sup 125}I, and glycosidase treatments, respectively. The myristate label was resistant to mild alkaline methanolysis and was found in fatty acid and sphingosine, indicating an unusual form of lipidmore » attachment to CD45.« less

[Nutrition and biological value of food parts of a trade bivalve mollusk Anadara broughtoni].

PubMed

Tabakaeva, O V; Tabakaev, A V

2015-01-01

Currently, the human diet includes different new products of seafishing, including non-fish--bivalves and gastropods, holothurias, echinoderms, jellyfishes that demands careful studying of their chemical composition. The purpose of the study was to determine the nutritional and biological value of all soft parts of the burrowing bivalve MOLLUSK Anadara broughtoni from the Far East region. It was established thatfood parts of a bivalve were significantly flooded (water content--73.5-84.2%), with the minimum water content in the adductor and maximum in the mantle. Dry solids are presented by organic (89-93%) and mineral (7-11%) components. Organic components consist of protein (14.6-20.7%), lipids (1.8-2.3%), carbohydrates (2.1-2.6%). The analysis of amino-acid composition of proteins of food parts of the mollusk of Anadara broughtonishowed the presence of all essential amino acids with slight differences in their content depending on the localization of the protein. All edible parts have tryptophan as the limiting amino acid. Muscle proteins have maximum level of lysine, methionine, cysteine, phenylalanine and tyrosine; mantle proteins--leucine, isoleucine and threonine; adductor proteins--valine, phenylalanine, tyrosine, methionine and cysteine. Predominant nonessential amino acids forproteins of all food pieces are glycine, aspartic acid, glutamic acid, arginine. The coefficient of amino-acid score differences of adductor protein (31.7%) is less than the same of cloak by 3.7%. The indicator "biological value" is maximal for adductor (68.3%), but the differenceformuscle is only 0.83%. Mantle proteins are characterized by minimum biological value (64.6%). The coefficient of utility of amino acid composition of protein is maximalfor muscle (57.83%), and values for a cloak and an adductor differ slightly (55.81 and 55.96%). Taurine content in food parts of a mollusk Anadara broughtoni is rather high compared to with other bivalve mollusks of the Far East region. Muscle tissue has maximal content of taurine (569.3 +/- 28.2 mg/100 g wet tissue), adductor occupies an intermediate position (387.9 +/- 18.2 mg/100 g wet tissue) and the minimum content of this amino acid is characteristic for mantle (297.1 +/- 13.4 mg/100 g wet tissue).

Deuterium isotope effect on 13C chemical shifts of tetrabutylammonium salts of Schiff bases amino acids.

PubMed

Rozwadowski, Z

2006-09-01

Deuterium isotope effects on 13C chemical shift of tetrabutylammonium salts of Schiff bases, derivatives of amino acids (glycine, L-alanine, L-phenylalanine, L-valine, L-leucine, L-isoleucine and L-methionine) and various ortho-hydroxyaldehydes in CDCl3 have been measured. The results have shown that the tetrabutylammonium salts of the Schiff bases amino acids, being derivatives of 2-hydroxynaphthaldehyde and 3,5-dibromosalicylaldehyde, exist in the NH-form, while in the derivatives of salicylaldehyde and 5-bromosalicylaldehyde a proton transfer takes place. The interactions between COO- and NH groups stabilize the proton-transferred form through a bifurcated intramolecular hydrogen bond. Copyright (c) 2006 John Wiley & Sons, Ltd.

Co-oxidation of the sulfur-containing amino acids in an autoxidizing lipid system

USGS Publications Warehouse

Wedemeyer, G.A.; Dollar, A.M.

1963-01-01

Oxidation of the sulfur amino acids by autoxidizing lipids was studied in a model system consisting of an amino acid dispersed in cold-pressed, molecularly distilled menhaden oil (20–80% w/w). Under all conditions investigated, cysteine was oxidized completely to cystine. Preliminary results suggest that at 110°C the oxidation follows first-order kinetics for at least the first 8 hr. A specific reaction rate constant of 0.25 per hour was calculated. When fatty acids were added to the system, cystine was oxidized to its thiosulfinate ester. When the fatty acid-cystine ratio was 1:2, oxidation of cystine was a maximum. No oxidation of cystine occurred unless either a fatty acid, volatile organic acid, or ethanol was added. Under the conditions investigated, methionine was not oxidized to either its sulfoxide or its sulfone.

Ion Chromatography Based Urine Amino Acid Profiling Applied for Diagnosis of Gastric Cancer

PubMed Central

Fan, Jing; Hong, Jing; Hu, Jun-Duo; Chen, Jin-Lian

2012-01-01

Aim. Amino acid metabolism in cancer patients differs from that in healthy people. In the study, we performed urine-free amino acid profile of gastric cancer at different stages and health subjects to explore potential biomarkers for diagnosing or screening gastric cancer. Methods. Forty three urine samples were collected from inpatients and healthy adults who were divided into 4 groups. Healthy adults were in group A (n = 15), early gastric cancer inpatients in group B (n = 7), and advanced gastric cancer inpatients in group C (n = 16); in addition, two healthy adults and three advanced gastric cancer inpatients were in group D (n = 5) to test models. We performed urine amino acids profile of each group by applying ion chromatography (IC) technique and analyzed urine amino acids according to chromatogram of amino acids standard solution. The data we obtained were processed with statistical analysis. A diagnostic model was constructed to discriminate gastric cancer from healthy individuals and another diagnostic model for clinical staging by principal component analysis. Differentiation performance was validated by the area under the curve (AUC) of receiver-operating characteristic (ROC) curves. Results. The urine-free amino acid profile of gastric cancer patients changed to a certain degree compared with that of healthy adults. Compared with healthy adult group, the levels of valine, isoleucine, and leucine increased (P < 0.05), but the levels of histidine and methionine decreased (P < 0.05), and aspartate decreased significantly (P < 0.01). The urine amino acid profile was also different between early and advanced gastric cancer groups. Compared with early gastric cancer, the levels of isoleucine and valine decreased in advanced gastric cancer (P < 0.05). A diagnosis model constructed for gastric cancer with AUC value of 0.936 tested by group D showed that 4 samples could coincide with it. Another diagnosis model for clinical staging with an AUC value of 0.902 tested by 3 advanced gastric cancer inpatients of group D showed that all could coincide with the model. Conclusions. The noticeable differences of urine-free amino acid profiles between gastric cancer patients and healthy adults indicate that such amino acids as valine, isoleucine, leucine, methionine, histidine and aspartate are important metabolites in cell multiplication and gene expression during tumor growth and metastatic process. The study suggests that urine-free amino acid profiling is of potential value for screening or diagnosing gastric cancer. PMID:22888338

Gene cloning, recombinant expression, purification and characterization of l-methionine decarboxylase from Streptomyces sp. 590.

PubMed

Hayashi, Masaya; Okada, Akane; Yamamoto, Kumiko; Okugochi, Tomomi; Kusaka, Chika; Kudou, Daizou; Nemoto, Michiko; Inagaki, Junko; Hirose, Yuu; Okajima, Toshihide; Tamura, Takashi; Soda, Kenji; Inagaki, Kenji

2017-04-01

l-Methionine decarboxylase (MetDC) from Streptomyces sp. 590 depends on pyridoxal 5'-phosphate and catalyzes the non-oxidative decarboxylation of l-methionine to produce 3-methylthiopropylamine and carbon dioxide. MetDC gene (mdc) was determined to consist of 1,674 bp encoding 557 amino acids, and the amino acid sequence is similar to that of l-histidine decarboxylases and l-valine decarboxylases from Streptomyces sp. strains. The mdc gene was cloned and recombinant MetDC was heterologously expressed by Escherichia coli. The purification of recombinant MetDC was carried out by DEAE-Toyopearl and Ni-NTA agarose column chromatography. The recombinant enzyme was homodimeric with a molecular mass of 61,000 Da and showed optimal activity between 45 to 55 °C and at pH 6.6, and the stability below 30 °C and between pH 4.6 to 7.0. l-Methionine and l-norleucine were good substrates for MetDC. The Michaelis constants for l-methionine and l-norleucine were 30 and 73 mM, respectively. The recombinant MetDC (0.50 U/ml) severely inhibited growth of human tumour cells A431 (epidermoid ovarian carcinoma cell line) and MDA-MB-231 (breast cancer cell line), however showed relatively low cytotoxicity for human normal cell NHDF-Neo (dermal fibroblast cell line from neonatal foreskin). This study revealed the properties of the gene and the protein sequence of MetDC for the first time. © The Authors 2017. Published by Oxford University Press on behalf of the Japanese Biochemical Society. All rights reserved.

Spectral and thermal study of the ternary complexes of nickel with sulfasalazine and some amino acids

NASA Astrophysics Data System (ADS)

Soliman, Ahmed A.

2006-12-01

The ternary complexes of Ni(II) with sulfasalazine (H 3SS) as a primary ligand and alanine (ala), aspartic acid (asp), histidene (hist), methionine (meth) and serine (ser) amino acids as secondary ligands have been synthesized. Characterization of the complexes was based on elemental analyses, IR, UV-vis, mass spectra, magnetic moment and thermal analysis (TG). The isolated complexes were found to have the general formula [M(HSS)(AA)]4H 2O (AA = ala, asp, hist, meth, or ser amino acid) where nickel is tetra-coordinated. The thermal stability of the complexes was studied and the weight losses for the decomposition of the complexes were calculated and correlated with the mass fragmentation pattern. In most cases, the amino acid moiety is removed along with the Schiff base moiety leaving NiO as a metallic residue. The metallic residue was confirmed by powder XRD measurements.

Responses to betaine and inorganic sulphur of sheep in growth performance and fibre growth.

PubMed

Nezamidoust, M; Alikhani, M; Ghorbani, G R; Edriss, M A

2014-12-01

Sulphur-containing amino acids (SAA) are essential and usually the first limiting amino acids for growth, milk and wool production. The keratin fibre that grows from epidermal tissue is rich in SAA. The rate of fibre growth and its S content are influenced by the availability of SAA. Betaine is a dietary source for a labile methyl group and actively participates in methionine metabolism by donating methyl groups for the remethylation of homocysteine to methionine. Ruminants are capable of synthesizing SAA from inorganic S sources, and most bacteria in the rumen can use inorganic S to meet their requirements for growth. The objective of this study was to examine whether betaine and an inorganic sulphur supplement could provide methyl groups and sulphur amino acids in a way that growth performance and wool production of ewes and lambs are improved. Treatments performed included betaine supplementation, sulphate supplementation and betaine plus sulphate supplementation with five replications for each treatment. The dry matter intake of the ewes was affected by betaine plus sulphate supplementation (p < 0.05). In the ewes, betaine plus sulphate supplementation increased (p < 0.05) the wool growth rate, wool yield, staple length and wool sulphur concentration, while decreasing wool wax and wool yellowness (p < 0.05). In the lambs, wool growth rate, wool yield, fibre diameter, staple length, staple strength, wool sulphur concentration, wool wax and fibre percentage did not differ (p > 0.05) between treatments. In the ewes, plasma methionine concentration increased (p < 0.05) with betaine plus sulphate treatment. No corresponding difference (p > 0.05) was observed in plasma methionine concentration in the lambs. It can be concluded that betaine plus sulphate supplementation has the potential to change wool characteristics in the ewes, while these compounds were without any effect on growth and wool production of the lambs. Combining the two supplements was advantageous. Journal of Animal Physiology and Animal Nutrition © 2014 Blackwell Verlag GmbH.

Capsaicinoids, amino acid and fatty acid profiles in different fruit components of the world hottest Naga king chilli (Capsicum chinense Jacq).

PubMed

Ananthan, R; Subhash, K; Longvah, T

2018-01-01

The world hottest Naga king chilli is cultivated and consumed in Northeast India. Capsaicinoids, amino acids and fatty acids were studied in fruit and fruit components of Naga king chilli. Capsaicinoid content was increased in each ripening stage and maximum level was observed at red color fruits. Total protein and fat content of placenta was 19.41 and 20.36% respectively. Capsaicinoids of placenta (7.35±2.241%) was higher followed by seed (3.83±1.358%) and pericarp (2.91±0.667%). Similarly, essential amino acid content was also higher in placenta compared to other components. Amino acid score ranged from 37 to 38 with cystine and methionine as limiting amino acid. Low level of palmitic, stearic and α-linolenic acid and very high level of linoleic acid were found in seeds. Total polyunsaturates of seeds were higher followed by whole fruit. Naga king chilli is unique due to its high capsaicinoid content and it offers potential crop for the future exploitation. Copyright © 2016 Elsevier Ltd. All rights reserved.

Amino acid levels in nascent metabolic syndrome: A contributor to the pro-inflammatory burden.

PubMed

Reddy, Priya; Leong, Joseph; Jialal, Ishwarlal

2018-05-01

Metabolic Syndrome (MetS) is a cluster of cardio-metabolic risk factors characterized by low-grade inflammation which confers an increased risk for type 2 diabetes mellitus (T2DM) and cardiovascular disease (CVD). Prior studies have linked elevated branched chain amino acids (BCAA) and aromatic amino acids (AAA) with T2DM and CVD. Due to the paucity of data in MetS, the aim of this study was to investigate the status of amino acids as early biomarkers of nascent MetS patients without T2DM and CVD or smoking. Healthy controls (n = 20) and MetS (n = 29) patients were recruited for the study. MetS was defined by criteria of National Cholesterol Education Program Adult Treatment Panel III of having at least 3 risk factors. Urinary amino acids were quantified by gas chromatography time-of-flight mass spectrometry at the Western NIH Metabolomics Center as expressed to urinary creatinine. Tyrosine and Isoleucine levels were significantly elevated in MetS patients. Isoleucine positively correlated with salient cardio-metabolic features and inflammatory biomarkers. Lysine and Methionine levels were decreased in MetS patients. Lysine correlated negatively with cardio-metabolic features and inflammatory bimarkers. Methionine also correlated negatively with blood pressure and certain inflammatory biomarkers. Our novel results suggest that with regards to the cardio-metabolic risk factors and pro-inflammatory features of MetS, isoleucine (BCAA) demonstrated a positive correlation while lysine demonstrated a negative correlation. Thus, increased levels of isoleucine and decreased levels of lysine could be potential early biomarkers of MetS. Copyright © 2018. Published by Elsevier Inc.

Degradation of Amino Acids and Structure in Model Proteins and Bacteriophage MS2 by Chlorine, Bromine, and Ozone.

PubMed

Choe, Jong Kwon; Richards, David H; Wilson, Corey J; Mitch, William A

2015-11-17

Proteins are important targets of chemical disinfectants. To improve the understanding of disinfectant-protein reactions, this study characterized the disinfectant:protein molar ratios at which 50% degradation of oxidizable amino acids (i.e., Met, Tyr, Trp, His, Lys) and structure were observed during HOCl, HOBr, and O3 treatment of three well-characterized model proteins and bacteriophage MS2. A critical question is the extent to which the targeting of amino acids is driven by their disinfectant rate constants rather than their geometrical arrangement. Across the model proteins and bacteriophage MS2 (coat protein), differing widely in structure, methionine was preferentially targeted, forming predominantly methionine sulfoxide. This targeting concurs with its high disinfectant rate constants and supports its hypothesized role as a sacrificial antioxidant. Despite higher HOCl and HOBr rate constants with histidine and lysine than for tyrosine, tyrosine generally was degraded in preference to histidine, and to a lesser extent, lysine. These results concur with the prevalence of geometrical motifs featuring histidines or lysines near tyrosines, facilitating histidine and lysine regeneration upon Cl[+1] transfer from their chloramines to tyrosines. Lysine nitrile formation occurred at or above oxidant doses where 3,5-dihalotyrosine products began to degrade. For O3, which lacks a similar oxidant transfer pathway, histidine, tyrosine, and lysine degradation followed their relative O3 rate constants. Except for its low reactivity with lysine, the O3 doses required to degrade amino acids were as low as or lower than for HOCl or HOBr, indicating its oxidative efficiency. Loss of structure did not correlate with loss of particular amino acids, suggesting the need to characterize the oxidation of specific geometric motifs to understand structural degradation.

Determination of amino acid contents of manketti seeds (Schinziophyton rautanenii) by pre-column derivatisation with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate and RP-HPLC.

PubMed

Gwatidzo, Luke; Botha, Ben M; McCrindle, Rob I

2013-12-01

Defatted kernel flour from manketti seed kernels (Schinziophyton rautanenii) is an underutilised natural product. The plant grows in the wild, on sandy soils little used for agriculture in Southern Africa. The kernels are rich in protein and have a great potential for improving nutrition. The protein content and amino acid profile of manketti seed kernel were studied, using a new analytical method, in order to evaluate the nutritional value. The crude protein content of the press cake and defatted kernel flour was 29.0% and 67.5%, respectively. Leucine and arginine were found to be the most abundant essential and non-essential amino acids, respectively. The seed kernel contained 4.77 g leucine and 12.34 g arginine/100 g of defatted seed kernel flour. Methionine and proline were the least abundant essential and non-essential amino acids to with 0.23 g methionine and 0.36 g proline/100 g of defatted seed kernel flour, respectively. Validation of the pre-column derivatisation procedure with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) for the determination of amino acids was carried out. The analytical parameters were determined: linearity (0.0025-0.20 mM), accuracy of the derivatisation procedure: 86.7-109.8%, precision (method: 0.72-5.04%, instrumental: 0.14-1.88% and derivatisation: 0.15-2.94% and 0.41-4.32% for intraday and interday, respectively). Limits of detection and quantification were 6.80-157 mg/100 g and 22.7-523 mg/100 g kernel flour, respectively. Copyright © 2013 Elsevier Ltd. All rights reserved.

A Novel Concept of Amino Acid Supplementation to Improve the Growth of Young Malnourished Male Rats.

PubMed

Furuta, Chie; Murakami, Hitoshi

2018-01-01

This study was aimed at understanding the relationship between plasma amino acids and protein malnutrition and at determining whether amino acid supplementation associated with malnutrition and growth improves linear growth in growing rats. Body length and plasma amino acids were measured in young male rats that were fed the following diet for 3 weeks, mimicking a low and imbalanced protein diets based on maize, a major staple consumed in developing countries: a 70% calorically restricted cornmeal-based diet (C), C + micronutrients (CM), CM + casein (CMC), CM + soy protein (CMS) or CMS + 0.3% lysine. A correlation analysis of linear growth and plasma amino acids indicated that lysine, tryptophan, branched-chain amino acids, methionine, and phenylalanine significantly correlated with body length. Supplementation with these 5 amino acids (AA1) significantly improved the body length in rats compared to CMC treatment whereas, nitrogen-balanced amino acid supplemented controls (AA2) did not (CM +1.2 ± 0.2, CMC +2.7 ± 0.3, CMS +2.1 ± 0.3, AA1 +2.8 ± 0.2, and AA2 +2.5 ± 0.3 cm). With securing proper amino acid balance, supplementing growth-related amino acids is more effective in improving linear growth in malnourished growing male rats. Analysis of the correlation between plasma amino acids and growth represents a powerful tool to determine candidate amino acids for supplementation to prevent malnutrition. This technology is adaptable to children in developing countries. © 2018 S. Karger AG, Basel.

Post-translational modification of ribosomally synthesized peptides by a radical SAM epimerase in Bacillus subtilis

NASA Astrophysics Data System (ADS)

Benjdia, Alhosna; Guillot, Alain; Ruffié, Pauline; Leprince, Jérôme; Berteau, Olivier

2017-07-01

Ribosomally synthesized peptides are built out of L-amino acids, whereas D-amino acids are generally the hallmark of non-ribosomal synthetic processes. Here we show that the model bacterium Bacillus subtilis is able to produce a novel type of ribosomally synthesized and post-translationally modified peptide that contains D-amino acids, and which we propose to call epipeptides. We demonstrate that a two [4Fe-4S]-cluster radical S-adenosyl-L-methionine (SAM) enzyme converts L-amino acids into their D-counterparts by catalysing Cα-hydrogen-atom abstraction and using a critical cysteine residue as the hydrogen-atom donor. Unexpectedly, these D-amino acid residues proved to be essential for the activity of a peptide that induces the expression of LiaRS, a major component of the bacterial cell envelope stress-response system. Present in B. subtilis and in several members of the human microbiome, these epipeptides and radical SAM epimerases broaden the landscape of peptidyl structures accessible to living organisms.

Solubility of xenon in amino-acid solutions. II. Nine less-soluble amino acids

NASA Astrophysics Data System (ADS)

Kennan, Richard P.; Himm, Jeffrey F.; Pollack, Gerald L.

1988-05-01

Ostwald solubility (L) of xenon gas, as the radioisotope 133Xe, has been measured as a function of solute concentration, at 25.0 °C, in aqueous solutions of nine amino acids. The amino-acid concentrations investigated covered much of their solubility ranges in water, viz., asparagine monohydrate (0-0.19 M), cysteine (0-1.16 M), glutamine (0-0.22 M), histidine (0-0.26 M), isoleucine (0-0.19 M), methionine (0-0.22 M), serine (0-0.38 M), threonine (0-1.4 M), and valine (0-0.34 M). We have previously reported solubility results for aqueous solutions of six other, generally more soluble, amino acids (alanine, arginine, glycine, hydroxyproline, lysine, and proline), of sucrose and sodium chloride. In general, L decreases approximately linearly with increasing solute concentration in these solutions. If we postulate that the observed decreases in gas solubility are due to hydration, the results under some assumptions can be used to calculate hydration numbers (H), i.e., the number of H2O molecules associated with each amino-acid solute molecule. The average values of hydration number (H¯) obtained at 25.0 °C are 15.3±1.5 for asparagine, 6.8±0.3 for cysteine, 11.5±1.1 for glutamine, 7.3±0.7 for histidine, 5.9±0.4 for isoleucine, 10.6±0.8 for methionine, 11.2±1.3 for serine, 7.7± 1.0 for threonine, and 6.6±0.6 for valine. We have also measured the temperature dependence of solubility L(T) from 5-40 °C for arginine, glycine, and proline, and obtained hydration numbers H¯(T) in this range. Between 25-40 °C, arginine has an H¯ near zero. This may be evidence for an attractive interaction between xenon and arginine molecules in aqueous solution.

A review of methionine dependency and the role of methionine restriction in cancer growth control and life-span extension.

PubMed

Cavuoto, Paul; Fenech, Michael F

2012-10-01

Methionine is an essential amino acid with many key roles in mammalian metabolism such as protein synthesis, methylation of DNA and polyamine synthesis. Restriction of methionine may be an important strategy in cancer growth control particularly in cancers that exhibit dependence on methionine for survival and proliferation. Methionine dependence in cancer may be due to one or a combination of deletions, polymorphisms or alterations in expression of genes in the methionine de novo and salvage pathways. Cancer cells with these defects are unable to regenerate methionine via these pathways. Defects in the metabolism of folate may also contribute to the methionine dependence phenotype in cancer. Selective killing of methionine dependent cancer cells in co-culture with normal cells has been demonstrated using culture media deficient in methionine. Several animal studies utilizing a methionine restricted diet have reported inhibition of cancer growth and extension of a healthy life-span. In humans, vegan diets, which can be low in methionine, may prove to be a useful nutritional strategy in cancer growth control. The development of methioninase which depletes circulating levels of methionine may be another useful strategy in limiting cancer growth. The application of nutritional methionine restriction and methioninase in combination with chemotherapeutic regimens is the current focus of clinical studies. Copyright © 2012 Elsevier Ltd. All rights reserved.

Biased expression, under the control of single promoter, of human interferon α-2b and Escherichia coli methionine amino peptidase genes in E. coli, irrespective of their distance from the promoter.

PubMed

Arif, Amina; Rashid, Naeem; Aslam, Farheen; Mahmood, Nasir; Akhtar, Muhammad

2016-03-01

Human interferon α-2b and Escherichia coli methionine amino peptidase genes were cloned independently as well as bicistronically in expression plasmid pET-21a (+). Production of human interferon α-2b was comparable to that of E. coli methionine amino peptidase when these genes were expressed independently in E. coli BL21-CodonPlus (DE3)-RIL. However, human interferon α-2b was produced in a much less amount whereas there was no difference in the production of methionine amino peptidase when the encoding genes were expressed bicistronically. It is important to note that human interferon α-2b was the first gene in order, after the promoter and E. coli methionine amino peptidase was the next with a linker sequence of 27 nucleotides between them.

Amino Acids Regulate mTORC1 by an Obligate Two-step Mechanism*

PubMed Central

Dyachok, Julia; Earnest, Svetlana; Iturraran, Erica N.; Cobb, Melanie H.

2016-01-01

The mechanistic target of rapamycin complex 1 (mTORC1) coordinates cell growth with its nutritional, hormonal, energy, and stress status. Amino acids are critical regulators of mTORC1 that permit other inputs to mTORC1 activity. However, the roles of individual amino acids and their interactions in mTORC1 activation are not well understood. Here we demonstrate that activation of mTORC1 by amino acids includes two discrete and separable steps: priming and activation. Sensitizing mTORC1 activation by priming amino acids is a prerequisite for subsequent stimulation of mTORC1 by activating amino acids. Priming is achieved by a group of amino acids that includes l-asparagine, l-glutamine, l-threonine, l-arginine, l-glycine, l-proline, l-serine, l-alanine, and l-glutamic acid. The group of activating amino acids is dominated by l-leucine but also includes l-methionine, l-isoleucine, and l-valine. l-Cysteine predominantly inhibits priming but not the activating step. Priming and activating steps differ in their requirements for amino acid concentration and duration of treatment. Priming and activating amino acids use mechanisms that are distinct both from each other and from growth factor signaling. Neither step requires intact tuberous sclerosis complex of proteins to activate mTORC1. Concerted action of priming and activating amino acids is required to localize mTORC1 to lysosomes and achieve its activation. PMID:27587390

Characterization of some amino acid derivatives of benzoyl isothiocyanate: Crystal structures and theoretical prediction of their reactivity

NASA Astrophysics Data System (ADS)

Odame, Felix; Hosten, Eric C.; Betz, Richard; Lobb, Kevin; Tshentu, Zenixole R.

2015-11-01

The reaction of benzoyl isothiocyanate with L-serine, L-proline, D-methionine and L-alanine gave 2-[(benzoylcarbamothioyl)amino]-3-hydroxypropanoic acid (I), 1-(benzoylcarbamothioyl)pyrrolidine-2-carboxylic acid (II), 2-[(benzoylcarbamothioyl)amino]-4-(methylsulfanyl)butanoic acid (III) and 2-[(benzoylcarbamothioyl)amino]propanoic acid (IV), respectively. The compounds have been characterized by IR, NMR, microanalyses and mass spectrometry. The crystal structures of all the compounds have also been discussed. Compound II showed rotamers in solution. DFT calculations of the frontier orbitals of the compounds have been carried out to ascertain the groups that contribute to the HOMO and LUMO, and to study their contribution to the reactivity of these compounds. The calculations indicated that the carboxylic acid group in these compounds is unreactive hence making the conversion to benzimidazoles via cyclization on the carboxylic acids impractical. This has been further confirmed by the reaction of compounds I-IV, respectively, with o-phenylene diamine which was unsuccessful but gave compound V.

Jugular-infused methionine, lysine and branched-chain amino acids does not improve milk production in Holstein cows experiencing heat stress.

PubMed

Kassube, K R; Kaufman, J D; Pohler, K G; McFadden, J W; Ríus, A G

2017-12-01

Poor utilization of amino acids contributes to losses of milk protein yield in dairy cows exposed to heat stress (HS). Our objective was to test the effect of essential amino acids on milk production in lactating dairy cows exposed to short-term HS conditions. To achieve this objective, 12 multiparous, lactating Holstein cows were assigned to two environments (thermoneutral (THN) or HS) from days 1 to 14 in a split-plot type cross-over design. All cows received 0 g/day of essential amino acids from days 1 to 7 (negative control (NC)) followed by an intravenous infusion of l-methionine (12 g/day), l-lysine (21 g/day), l-leucine (35 g/day), l-isoleucine (15 g/day) and l-valine (15 g/day, methionine, lysine and branched-chain amino acids (ML+BCAA)) from days 8 to 14. The basal diet was composed of ryegrass silage and hay, and a concentrate mix. This diet supplied 44 g of methionine, 125 g of lysine, 167 g of leucine, 98 g of isoleucine and 109 g of valine per day to the small intestine of THN cows. Temperature-humidity index was maintained below 66 for the THN environment, whereas the index was maintained above 68, peaking at 76, for 14 continuous h/day for the HS environment. Heat stress conditioning increased the udder temperature from 37.0°C to 39.6°C. Cows that received the ML+BCAA treatment had greater p.m. rectal and vaginal temperatures (0.50°C and 0.40°C, respectively), and respiration rate (8 breaths/min) compared with those on the NC treatment and exposed to a HS environment. However, neither NC nor ML+BCAA affected rectal or vaginal temperatures and respiration rates in the THN environment. Compared with THN, the HS environment reduced dry matter intake (1.48 kg/day), milk yield (2.82 kg/day) and milk protein yield (0.11 kg/day). However, compared with NC, the ML+BCAA treatment increased milk protein percent by 0.07 points. For the THN environment, the ML+BCAA treatment increased concentrations of milk urea nitrogen. For the HS environment, the ML+BCAA treatment decreased plasma concentrations of arginine, ornithine and citrulline; however, differences were not observed for the THN environment. In summary, HS elicited expected changes in production; however, infusions of ML+BCAA failed to increase milk protein yield. Lower dry matter intake and greater heat load in response to ML+BCAA contributed to the lack of response in milk production in HS cows. The ML+BCAA treatment may have reduced the breakdown of muscle protein in heat-stressed cows.

CSF/plasma ratios of amino acids: reference data and transports in children.

PubMed

Akiyama, Tomoyuki; Kobayashi, Katsuhiro; Higashikage, Akihito; Sato, Junko; Yoshinaga, Harumi

2014-01-01

We intended to investigate the effects of age, gender, and medications on amino acid cerebrospinal fluid (CSF)/plasma ratios in children, and to determine whether amino acid transports across the blood-CSF barrier in children differ from those in adults. Amino acid concentrations measured by ion-exchange high-performance liquid chromatography were used (CSF from 99 children, simultaneously collected plasma from 76 children). Influence of age, gender, and medications on the amino acid CSF concentrations and CSF/plasma ratios were analyzed by linear multiple regression. Interactions of amino acid transports were analyzed by correlation analysis of CSF/plasma ratios. CSF/plasma ratios of serine, valine, histidine, and arginine were higher in younger children. The glutamate CSF/plasma ratio was higher in older children. Serine, alanine, threonine, valine, and histidine CSF/plasma ratios were lower in females. Glutamine, methionine, tyrosine, and phenylalanine CSF/plasma ratios were elevated with valproate therapy. Serine, threonine, valine, leucine, and tyrosine CSF/plasma ratios were lower with clobazam therapy. The asparagine CSF/plasma ratio was elevated with pyridoxal phosphate therapy. Transports of most essential neutral amino acids interacted with each other, as did neutral amino acids with low molecular weights. Cationic amino acids interacted with each other and some essential neutral amino acids. Acidic amino acids had no interactions with other amino acids. Age, gender, and anti-epileptic drugs affect amino acid CSF/plasma ratios in children. Transport interactions between amino acids in children showed no remarkable difference from those of adults and generally followed the substrate specificities of multiple amino acid transport systems. Copyright © 2012 The Japanese Society of Child Neurology. Published by Elsevier B.V. All rights reserved.

A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

PubMed

Meher, Hari Charan; Gajbhiye, Vijay T; Singh, Ghanendra

2011-01-01

A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.).

Molecular composition and seasonal variation of amino acids in urban aerosols from Beijing, China

NASA Astrophysics Data System (ADS)

Ren, Lujie; Bai, Huahua; Yu, Xi; Wu, Fengchang; Yue, Siyao; Ren, Hong; Li, Linjie; Lai, Senchao; Sun, Yele; Wang, Zifa; Fu, Pingqing

2018-05-01

Fifteen hydrolyzed amino acids (THAA) were quantified in urban aerosols (TSP samples) collected during April 2012 to May 2013 in Beijing, China using high-performance liquid chromatography (HPLC) after their derivatization with o-phthalaldehyde (OPA), to investigate their molecular distributions and seasonal variation. Total concentrations of amino acids ranged from 1.73-25.7 nmol m- 3 with a peak in spring (13.7 nmol m- 3), followed by winter (11.5 nmol m- 3), fall (9.51 nmol m- 3) and summer (7.45 nmol m- 3). Glycine (Gly), alanine (Ala) and valine (Val) are found to be the most abundant species, which account for 46% of the total THAA. Compared with those recorded in previous studies, the atmospheric levels of amino acids in Beijing were higher than those from other regions. Enhanced amounts of methionine, tyrosine, histidine, aspartic acid and glutamic acid were found during the rainfall events. The factor analysis further suggests that amino acids in urban Beijing originated from multiple sources including biological emission, biomass burning, as well as anthropogenic activities.

Non-standard amino acid recognition by Escherichia coli leucyl-tRNA synthetase

NASA Technical Reports Server (NTRS)

Martinis, S. A.; Fox, G. E.

1997-01-01

Recombinant E. coli leucyl-tRNA synthetase was screened for amino acid-dependent pyrophosphate exchange activity using noncognate aliphatic amino acids including norvaline, homocysteine, norleucine, methionine, and homoserine. [32P]-labeled reaction products were separated by thin layer chromatography using a novel solvent system and then quantified by phosphorimaging. Norvaline which differs from leucine by only one methyl group stimulated pyrophosphate exchange activity as did both homocysteine and norleucine to a lesser extent. The KM parameters for leucine and norvaline were measured to be 10 micromoles and 1.5 mM, respectively. Experiments are in progress to determine if norvaline is transferred to tRNA(Leu) and/or edited by a pre- or post-transfer mechanism.

Chemical composition and nutritional potential of yam bean seeds (Pachyrhizus erosus L. urban).

PubMed

Santos, A C; Cavalcanti, M S; Coelho, L C

1996-01-01

Pachyrhizus erosus seeds were analysed for proximate composition, minerals, protein fractions, antinutritional factors, and rotenoids. The seeds showed a high content of proteins, lipids, Fe and Ca, in comparison to other legumes. Glutelins constitute the highest protein fraction, followed by globulins. Antinutritional substances detected as tannins, hemagglutinating activity and trypsin inhibitory activity, were in low concentrations. Seeds were also processed to obtain a flour which showed proper characteristics, good in vitro digestibility, significant rotenoid reduction level and amino acid composition rich in essential amino acids, except methionine.

Functional Modification of Thioether Groups in Peptides, Polypeptides, and Proteins.

PubMed

Deming, Timothy J

2017-03-15

Recent developments in the modification of methionine and other thioether-containing residues in peptides, polypeptides, and proteins are reviewed. Properties and potential applications of the resulting functionalized products are also discussed. While much of this work is focused on natural Met residues, modifications at other side-chain residues have also emerged as new thioether-containing amino acids have been incorporated into peptidic materials. Functional modification of thioether-containing amino acids has many advantages and is a complementary methodology to the widely utilized methods for modification at cysteine residues.

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China.

PubMed

Cao, Xiaochuang; Ma, Qingxu; Zhong, Chu; Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

2016-01-01

Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3--N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many amino acids across the elevational gradient suggests that soil amino acids likely originate from a common source or through similar biochemical processes.

Elevational Variation in Soil Amino Acid and Inorganic Nitrogen Concentrations in Taibai Mountain, China

PubMed Central

Yang, Xin; Zhu, Lianfeng; Zhang, Junhua; Jin, Qianyu; Wu, Lianghuan

2016-01-01

Amino acids are important sources of soil organic nitrogen (N), which is essential for plant nutrition, but detailed information about which amino acids predominant and whether amino acid composition varies with elevation is lacking. In this study, we hypothesized that the concentrations of amino acids in soil would increase and their composition would vary along the elevational gradient of Taibai Mountain, as plant-derived organic matter accumulated and N mineralization and microbial immobilization of amino acids slowed with reduced soil temperature. Results showed that the concentrations of soil extractable total N, extractable organic N and amino acids significantly increased with elevation due to the accumulation of soil organic matter and the greater N content. Soil extractable organic N concentration was significantly greater than that of the extractable inorganic N (NO3−-N + NH4+-N). On average, soil adsorbed amino acid concentration was approximately 5-fold greater than that of the free amino acids, which indicates that adsorbed amino acids extracted with the strong salt solution likely represent a potential source for the replenishment of free amino acids. We found no appreciable evidence to suggest that amino acids with simple molecular structure were dominant at low elevations, whereas amino acids with high molecular weight and complex aromatic structure dominated the high elevations. Across the elevational gradient, the amino acid pool was dominated by alanine, aspartic acid, glycine, glutamic acid, histidine, serine and threonine. These seven amino acids accounted for approximately 68.9% of the total hydrolyzable amino acid pool. The proportions of isoleucine, tyrosine and methionine varied with elevation, while soil major amino acid composition (including alanine, arginine, aspartic acid, glycine, histidine, leucine, phenylalanine, serine, threonine and valine) did not vary appreciably with elevation (p>0.10). The compositional similarity of many amino acids across the elevational gradient suggests that soil amino acids likely originate from a common source or through similar biochemical processes. PMID:27337100

Effect of intravenous administration of D-lysergic acid diethylamide on initiation of protein synthesis in a cell-free system derived from brain.

PubMed

Cosgrove, J W; Brown, I R

1984-05-01

An initiating cell-free protein synthesis system derived from brain was utilized to demonstrate that the intravenous injection of D-lysergic acid diethylamide (LSD) to rabbits resulted in a lesion at the initiation stage of brain protein synthesis. Three inhibitors of initiation, edeine, poly(I), and aurintricarboxylic acid were used to demonstrate a reduction in initiation-dependent amino acid incorporation in the brain cell-free system. One hour after LSD injection, there was also a measurable decrease in the formation of 40S and 80S initiation complexes in vitro, using either [35S]methionine or [35S]Met-tRNAf. Analysis of the methionine pool size after LSD administration indicated there was no change in methionine levels. Analysis of the formation of initiation complexes in the brain cell-free protein synthesis system prepared 6 h after LSD administration indicated that there was a return to control levels at this time. The effects of LSD on steps in the initiation process are thus reversible.

Optimization of response surface and neural network models in conjugation with desirability function for estimation of nutritional needs of methionine, lysine, and threonine in broiler chickens.

PubMed

Mehri, Mehran

2014-07-01

The optimization algorithm of a model may have significant effects on the final optimal values of nutrient requirements in poultry enterprises. In poultry nutrition, the optimal values of dietary essential nutrients are very important for feed formulation to optimize profit through minimizing feed cost and maximizing bird performance. This study was conducted to introduce a novel multi-objective algorithm, desirability function, for optimization the bird response models based on response surface methodology (RSM) and artificial neural network (ANN). The growth databases on the central composite design (CCD) were used to construct the RSM and ANN models and optimal values for 3 essential amino acids including lysine, methionine, and threonine in broiler chicks have been reevaluated using the desirable function in both analytical approaches from 3 to 16 d of age. Multi-objective optimization results showed that the most desirable function was obtained for ANN-based model (D = 0.99) where the optimal levels of digestible lysine (dLys), digestible methionine (dMet), and digestible threonine (dThr) for maximum desirability were 13.2, 5.0, and 8.3 g/kg of diet, respectively. However, the optimal levels of dLys, dMet, and dThr in the RSM-based model were estimated at 11.2, 5.4, and 7.6 g/kg of diet, respectively. This research documented that the application of ANN in the broiler chicken model along with a multi-objective optimization algorithm such as desirability function could be a useful tool for optimization of dietary amino acids in fractional factorial experiments, in which the use of the global desirability function may be able to overcome the underestimations of dietary amino acids resulting from the RSM model. © 2014 Poultry Science Association Inc.

Oral branched-chain amino acids decrease whole-body proteolysis

NASA Technical Reports Server (NTRS)

Ferrando, A. A.; Williams, B. D.; Stuart, C. A.; Lane, H. W.; Wolfe, R. R.

1995-01-01

BACKGROUND: This study reports the effects of ingesting branched-chain amino acids (leucine, valine, and isoleucine) on protein metabolism in four men. METHODS: To calculate leg protein synthesis and breakdown, we used a new model that utilized the infusion of L-[ring-13C6]phenylalanine and the sampling of the leg arterial-venous difference and muscle biopsies. In addition, protein-bound enrichments provided for the direct calculation of muscle fractional synthetic rate. Four control subjects ingested an equivalent amount of essential amino acids (threonine, methionine, and histidine) to discern the effects of branched-chain amino acid nitrogen vs the effects of essential amino acid nitrogen. Each drink also included 50 g of carbohydrate. RESULTS: Consumption of the branched-chain and the essential amino acid solutions produced significant threefold and fourfold elevations in their respective arterial concentrations. Protein synthesis and breakdown were unaffected by branched-chain amino acids, but they increased by 43% (p < .05) and 36% (p < .03), respectively, in the group consuming the essential amino acids. However, net leg balance of phenylalanine was unchanged by either drink. Direct measurement of protein synthesis by tracer incorporation into muscle protein (fractional synthetic rate) revealed no changes within or between drinks. Whole-body phenylalanine flux was significantly suppressed by each solution but to a greater extent by the branched-chain amino acids (15% and 20%, respectively) (p < .001). CONCLUSIONS: These results suggest that branched-chain amino acid ingestion suppresses whole-body proteolysis in tissues other than skeletal muscle in normal men.

D-amino acid residue in a defensin-like peptide from platypus venom: effect on structure and chromatographic properties.

PubMed

Torres, Allan M; Tsampazi, Chryssanthi; Geraghty, Dominic P; Bansal, Paramjit S; Alewood, Paul F; Kuchel, Philip W

2005-10-15

The recent discovery that the natriuretic peptide OvCNPb (Ornithorhynchus venom C-type natriuretic peptide B) from platypus (Ornithorynchus anatinus) venom contains a D-amino acid residue suggested that other D-amino-acid-containing peptides might be present in the venom. In the present study, we show that DLP-2 (defensin-like peptide-2), a 42-amino-acid residue polypeptide in the platypus venom, also contains a D-amino acid residue, D-methionine, at position 2, while DLP-4, which has an identical amino acid sequence, has all amino acids in the L-form. These findings were supported further by the detection of isomerase activity in the platypus gland venom extract that converts DLP-4 into DLP-2. In the light of this new information, the tertiary structure of DLP-2 was recalculated using a new structural template with D-Met2. The structure of DLP-4 was also determined in order to evaluate the effect of a D-amino acid at position 2 on the structure and possibly to explain the large retention time difference observed for the two molecules in reverse-phase HPLC. The solution structures of the DLP-2 and DLP-4 are very similar to each other and to the earlier reported structure of DLP-2, which assumed that all amino acids were in the L-form. Our results suggest that the incorporation of the D-amino acid at position 2 has minimal effect on the overall fold in solution.

A Hemoglobin Variant Associated with Neonatal Cyanosis and Anemia

PubMed Central

Crowley, Moira A.; Mollan, Todd L.; Abdulmalik, Osheisa Y.; Butler, Andrew D.; Goodwin, Emily F.; Sarkar, Arindam; Stolle, Catherine A.; Gow, Andrew J.; Olson, John S.; Weiss, Mitchell J.

2013-01-01

SUMMARY Globin-gene mutations are a rare but important cause of cyanosis. We identified a missense mutation in the fetal G γ-globin gene (HBG2) in a father and daughter with transient neonatal cyanosis and anemia. This new mutation modifies the ligand-binding pocket of fetal hemoglobin by means of two mechanisms. First, the relatively large side chain of methionine decreases both the affinity of oxygen for binding to the mutant hemoglobin subunit and the rate at which it does so. Second, the mutant methionine is converted to aspartic acid post-translationally, probably through oxidative mechanisms. The presence of this polar amino acid in the heme pocket is predicted to enhance hemoglobin denaturation, causing anemia. PMID:21561349

Simultaneous and selective decarboxylation of L-serine and deamination of L-phenylalanine in an amino acid mixture--a means of separating amino acids for synthesizing biobased chemicals.

PubMed

Teng, Yinglai; Scott, Elinor L; Witte-van Dijk, Susan C M; Sanders, Johan P M

2016-01-25

Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. Copyright © 2015 Elsevier B.V. All rights reserved.

Partial amino-acid sequence of the precursor of an immunoglobulin light chain containing NH2-terminal pyroglutamic acid.

PubMed Central

Burstein, Y; Kantour, F; Schechter, I

1976-01-01

Analyses of amino-acid sequences of the total cell-free products programmed by the mRNA of MOPC-104E gamma light (L)-chain show that over 95% of the products have sequences of a distinct protein that correspond to the L-chain precursor. In this precursor an extra piece is coupled to the NH2-terminus of the mature L-chain. Analyses of products labeled with [3H]alanine, [3H]leucine, and [3H]proline demonstrate that the extra piece is composed of at least 18 residues. Analyses of [35S]methione-labeled product indicate that the extra piece may contain an additional NH2-terminal methionine, which is detected in about 10% of the molecules. Partial recovery of the NJ2-terminal methionine (alanine, leucine, and proline are recovered in yields close to theoretical, greater than 95%) suggests that it is the initiator methionine, which is known to be short lived in eukaryotes due to rapid hydrolysis. Thus, the extra piece seems to be 19 residues in length, and it contains one methionine at the NH2-terminus, three alanines at positions 2, 12, and 17, and five leucines at positions 6, 8, 10, 11, and 13. The close gathering of leucine residues, as well as their abundance (26%), suggest that the extra piece would be quite hydrophobic. Hydrophobicity seems to be a general property of the extra piece, since similar clusters of leucine were found in the precursors of 3 KL-chains (Burstein, Y. & Schechter, I. (1976) Biochem. J. 157, 145-151). The NH2-terminus of the mature MOPC-104E gamma L-chain is blocked by pyroglutamic acid. The fact that in the precursor a peptide segment precedes this NH2-terminus establishes that pyroglutamic acid is not the initiator residue for synthesis of the L-chain. Apparently, the pyroglutamic acid is formed by cyclization of glutamic acid or glutamine during cleavage of the extra piece to yield the mature L-chain. Images PMID:822420

Extending the cross-linking/mass spectrometry strategy: Facile incorporation of photo-activatable amino acids into the model protein calmodulin in Escherichia coli cells.

PubMed

Piotrowski, Christine; Ihling, Christian H; Sinz, Andrea

2015-11-01

Photo-induced cross-linking is a highly promising technique to investigate protein conformations and protein-protein interactions in their natural cellular environment. One strategy relies on the non-directed incorporation of diazirine-containing photo-activatable amino acids into proteins and a subsequent cross-link formation induced by UV-A irradiation. The advantage of this photo-cross-linking strategy is that it is not restricted to lysine residues and that hydrophobic regions in proteins can also be targeted, which is advantageous for investigating membrane proteins. Here, we present a simplified protocol that relies on the use of mineral salts medium without any special requirements for the incorporation of photo-methionines into proteins in Escherichia coli cells. The possibility to perform these experiments in E. coli is especially valuable as it is the major system for recombinant protein production. The method is exemplified for the Ca(2+) regulating protein calmodulin containing nine methionines, which were found to be replaced by their photo-activatable analogues. Our protocol allows the facile and stochastic incorporation of photo-methionines as the basis for conducting photo-cross-linking experiments in E. coli in an efficient manner. Copyright © 2015 Elsevier Inc. All rights reserved.

Identification of cysteine-644 as the covalent site of attachment of dexamethasone 21-mesylate to murine glucocorticoid receptors in WEHI-7 cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Smith, L.I.; Bodwell, J.E.; Mendel, D.B.

1988-05-17

Dexamethasone 21-mesylate is a highly specific synthetic glucocorticoid derivative that binds covalently to glucocorticoid receptors via sulfhydryl groups. The authors have identified the amino acid that reacts with the dexamethasone 21-mesylate by using enzymatic digestion and microsequencing for radiolabel. Nonactivated glucocorticoid receptors obtained from labeling intact WEHI-7 mouse thymoma cells with (/sup 3/H)dexamethasone 21-mesylate were immunopurified and analyzed by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Trypsin digestion followed by reversed-phase high-performance liquid chromatography (reversed-phase HPLC) produced a single (/sup 3/H)dexamethasone 21-mesylate labeled peptide. Automated Edman degradation of this peptide revealed that the (/sup 3/H)dexamethasone 21-mesylate was located at position 5 frommore » the amino terminus. Dual-isotope labeling studies with (/sup 3/H)dexamethasone 21-mesylate and (/sup 35/S)methionine demonstrated that this peptide contained methionine. Staphylococcus aureus V8 protease digestion of (/sup 3/H)dexamethasone 21-mesylate labeled steroid-binding subunits generated a different radiolabeled peptide containing label at position 7 from the amino terminus. On the basis of the published amino acid sequence of the murine glucocorticoid receptor, their data clearly identify cysteine-644 as the single residue in the steroid-binding domain that covalently binds dexamethasone 21-mesylate. They have confirmed this finding by demonstrating that a synthetic peptide representing the amino acid sequence 640-650 of the murine glucocorticoid receptor behaves in an identical manner on reversed-phase HPLC as the trypsin-generated peptide from intact cells.« less

Reactions of cisplatin with cysteine and methionine at constant pH; a computational study.

PubMed

Zimmermann, Tomás; Burda, Jaroslav V

2010-02-07

Interactions of hydrated cisplatin complexes cis-[Pt(NH(3))(2)Cl(H(2)O)](+) and cis-[Pt(NH(3))(2)(OH)(H(2)O)](+) with cysteine and methionine in an aqueous solution at constant pH were explored using computational methods. Thermodynamic parameters of considered reactions were studied in a broad pH range, taking up to 4 protonation states of each molecule into account. Reaction free energies at constant pH were obtained from standard Gibbs free energies using the Legendre transformation. Solvation free energies and pK(a) values were calculated using the PCM model with UAHF cavities, recently adapted by us for transition metal complexes. The root mean square error of pK(a) values on a set of model platinum complexes and amino acids was equal to 0.74. At pH 7, the transformed Gibbs free energies differ by up to 15 kcal mol(-1) from the Gibbs free energies of model reactions with a constant number of protons. As for cysteine, calculations confirmed a strong preference for kappaS monodenate bonding in a broad pH range. The most stable product of the second reaction step, which proceeds from monodentate to chelate complex, is the kappa(2)S,N coordinated chelate. The reaction with methionine is more complex. In the first step all three considered methionine donor atoms (N, S and O) are thermodynamically preferred products depending on the platinum complex and the pH. This is in accordance with the experimental observation of a pH dependent migration between N and S donor atoms in a chemically related system. The most stable chelates of platinum with methionine are kappa(2)S,N and kappa(2)N,O bonded complexes. The comparison of reaction free energies of both amino acids suggests, that the bidentate methionine ligand can be displaced even by the monodentate cysteine ligand under certain conditions.

AMINO ACID COMPOSITION OF HIGHLY PURIFIED VIRAL PARTICLES OF INFLUENZA A AND B

PubMed Central

Knight, C. A.

1947-01-01

Microbiological assays for amino acids were made on hydrolysates of four to five highly purified preparations each of influenza A virus (PR8 strain) and influenza B virus (Lee strain). The results of the assays indicated that these strains of influenza virus contain approximately the same amounts of alanine, aspartic acid, glycine, histidine, isoleucine, leucine, methionine, phenylalanine, proline, serine, threonine, and valine. However, significant differences were found in the values for arginine, glutamic acid, lysine, tryptophane, and tyrosine. It is believed that these differences may provide, at least in part, a chemical explanation for some of the differing properties of the PR8 and Lee strains of influenza viruses. PMID:19871660

Effect of starter cultures and packaging methods on amino acid profile and eating quality characteristics of pork ham.

PubMed

Gogoi, Protiva; Borpuzari, R N; Borpuzari, T; Hazarika, R A; Bora, J R

2015-08-01

Wet cured pork hams were inoculated with a mixed starter cultures comprising of Lactobacillus acidophilus and Micrococcus varians M483 at the dose level of 106 cfu/g and the un inoculated hams served as controls. The amino acid profile of hams of the treated and the control groups stored at 4oC under MAP and VP and evaluated on 60th day of storage revealed that treated hams liberated higher concentration of free amino acids except for proline and methionine which were found in higher concentration (P < 0.01) in the MAP control samples. The MAP control samples liberated glutamic acid (85.65 ± 1.40 ppm), cystine (21.56 ± 1.14 ppm) and tyrosine (16.63 ± 1.94 ppm) whereas, the treated samples did not release these amino acids. The VP control samples too liberated cystine (6.98 ± 1.36 ppm) and arginine (42.70 ± 2.78 ppm) but the treated ham of the VP did not liberate these amino acids. The VP hams had higher concentration (P < 0.01) of free proline, glycine, alanine, valine, methionine, isoleucine, phenylalanine, lysine and histidine than the MAP samples. Colour analysis of ham using CIE Lab colour system revealed that the treated samples had significantly higher concentrations of L*, a* and b* components. The L* and a* values were higher in the MAP than under VP systems while the b* values were higher in the VP samples than the MAP samples. Neither the bacterial cultures nor the packaging system influenced the textural property of ham. Starter cultures inoculated hams were rated superior (P < 0.05) in terms of their sensory properties. Hams packaged under MAP were rated superior (P < 0.05) than those packaged under VP in terms of appearance, colour, taste, tenderness, flavour, juiciness and overall acceptability.

Effects of aerosol formulation to amino acids and fatty acids contents in Haruan extract.

PubMed

Febriyenti; Bai-Baie, Saringat Bin; Laila, Lia

2012-01-01

Haruan (Channa striatus) extract was formulated to aerosol for wound and burn treatment. Haruan extract is containing amino acids and fatty acids that important for wound healing process. The purpose of this study is to observe the effect of formulation and other excipients in the formula to amino acids and fatty acids content in Haruan extract before and after formulated into aerosol. Precolumn derivatization with 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate (AQC) method is used for amino acids analysis. Fatty acids in Haruan extract were esterified using transesterification method to form FAMEs before analyzed using GC. Boron trifluoride-methanol reagent is used for transesterification. Tyrosine and methionine concentrations were different after formulated. The concentrations were decrease. There are six fatty acids have amount that significantly different after formulated into concentrate and aerosol. Contents of these fatty acids were increase. Generally, fatty acids which had content increased after formulated were the long-chain fatty acids. This might be happen because of chain extension process. Saponification and decarboxylation would give the chain extended product. Therefore contents of long-chain fatty acids were increase. Generally, the aerosol formulation did not affect the amino acids concentrations in Haruan extract while some long-chain fatty acids concentrations were increase after formulated into concentrate and aerosol.

Forced swimming and imipramine modify plasma and brain amino acid concentrations in mice.

PubMed

Murakami, Tatsuro; Yamane, Haruka; Tomonaga, Shozo; Furuse, Mitsuhiro

2009-01-05

The relationships between monoamine metabolism and forced swimming or antidepressants have been well studied, however information is lacking regarding amino acid metabolism under these conditions. Therefore, the aim of the present study was to investigate the effects of forced swimming and imipramine on amino acid concentrations in plasma, the cerebral cortex and the hypothalamus in mice. Forced swimming caused cerebral cortex concentrations of L-glutamine, L-alanine, and taurine to be increased, while imipramine treatment caused decreased concentrations of L-glutamate, L-alanine, L-tyrosine, L-methionine, and L-ornithine. In the hypothalamus, forced swimming decreased the concentration of L-serine while imipramine treatment caused increased concentration of beta-alanine. Forced swimming caused increased plasma concentration of taurine, while concentrations of L-serine, L-asparagine, L-glutamine and beta-alanine were decreased. Imipramine treatment caused increased plasma concentration of all amino acid, except for L-aspartate and taurine. In conclusion, forced swimming and imipramine treatment modify central and peripheral amino acid metabolism. These results may aid in the identification of amino acids that have antidepressant-like effects, or may help to refine the dosages of antidepressant drugs.

α-Amidoalkylating agents from N-acyl-α-amino acids: 1-(N-acylamino)alkyltriphenylphosphonium salts.

PubMed

Mazurkiewicz, Roman; Adamek, Jakub; Październiok-Holewa, Agnieszka; Zielińska, Katarzyna; Simka, Wojciech; Gajos, Anna; Szymura, Karol

2012-02-17

N-Acyl-α-amino acids were efficiently transformed in a two-step procedure into 1-N-(acylamino)alkyltriphenylphosphonium salts, new powerful α-amidoalkylating agents. The effect of the α-amino acid structure, the base used [MeONa or a silica gel-supported piperidine (SiO(2)-Pip)], and the main electrolysis parameters (current density, charge consumption) on the yield and selectivity of the electrochemical decarboxylative α-methoxylation of N-acyl-α-amino acids (Hofer-Moest reaction) was investigated. For most proteinogenic and all studied unproteinogenic α-amino acids, very good results were obtained using a substoichiometric amount of SiO(2)-Pip as the base. Only in the cases of N-acylated cysteine, methionine, and tryptophan, attempts to carry out the Hofer-Moest reaction in the applied conditions failed, probably because of the susceptibility of these α-amino acids to an electrochemical oxidation on the side chain. The methoxy group of N-(1-methoxyalkyl)amides was effectively displaced with the triphenylphosphonium group by dissolving an equimolar amount of N-(1-methoxyalkyl)amide and triphenylphosphonium tetrafluoroborate in CH(2)Cl(2) at room temperature for 30 min, followed by the precipitation of 1-N-(acylamino)alkyltriphenylphosphonium salt with Et(2)O.

Impact of primary amine group from aminophospholipids and amino acids on marine phospholipids stability: non-enzymatic browning and lipid oxidation.

PubMed

Lu, F S H; Nielsen, N S; Baron, C P; Diehl, B W K; Jacobsen, C

2013-11-15

The main objective of this study was to investigate the oxidative stability and non-enzymatic browning reactions of marine PL in the presence or in the absence of primary amine group from aminophospholipids and amino acids. Marine phospholipids liposomal dispersions were prepared from two authentic standards (phosphatidylcholine and phosphatidylethanolamine) and two purified PL from marine sources with and without addition of amino acids (leucine, methionine and lysine). Samples were incubated at 60°C for 0, 2, 4 and 6days. Non-enzymatic browning reactions were investigated through measurement of (i) Strecker derived volatiles, (ii) yellowness index (YI), (iii) hydrophobic and (iv) hydrophilic pyrroles content. The oxidative stability of the samples was assessed through measurement of secondary lipid derived volatile oxidation products. The result showed that the presence of PE and amino acids caused the formation of pyrroles, generated Strecker derived volatiles, decreased the YI development and lowered lipid oxidation. The lower degree of lipid oxidation in liposomal dispersions containing amino acids might be attributed to antioxidative properties of pyrroles or amino acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Child Stunting is Associated with Low Circulating Essential Amino Acids.

PubMed

Semba, Richard D; Shardell, Michelle; Sakr Ashour, Fayrouz A; Moaddel, Ruin; Trehan, Indi; Maleta, Kenneth M; Ordiz, M Isabel; Kraemer, Klaus; Khadeer, Mohammed A; Ferrucci, Luigi; Manary, Mark J

2016-04-01

Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of children. We used a targeted metabolomics approach to measure serum amino acids, glycerophospholipids, sphingolipids, and other metabolites using liquid chromatography-tandem mass spectrometry in 313 children, aged 12-59months, from rural Malawi. Children underwent anthropometry. Sixty-two percent of the children were stunted. Children with stunting had lower serum concentrations of all nine essential amino acids (tryptophan, isoleucine, leucine, valine, methionine, threonine, histidine, phenylalanine, lysine) compared with nonstunted children (p<0.01). In addition, stunted children had significantly lower serum concentrations of conditionally essential amino acids (arginine, glycine, glutamine), non-essential amino acids (asparagine, glutamate, serine), and six different sphingolipids compared with nonstunted children. Stunting was also associated with alterations in serum glycerophospholipid concentrations. Our findings support the idea that children with a high risk of stunting may not be receiving an adequate dietary intake of essential amino acids and choline, an essential nutrient for the synthesis of sphingolipids and glycerophospholipids. Copyright © 2016 The Authors. Published by Elsevier B.V. All rights reserved.

gamma-Glutamyl amino acids. Transport and conversion to 5-oxoproline in the kidney

DOE Office of Scientific and Technical Information (OSTI.GOV)

Bridges, R.J.; Meister, A.

1985-06-25

Transport of gamma-glutamyl amino acids, a step in the proposed glutathione-gamma-glutamyl transpeptidase-mediated amino acid transport pathway, was examined in mouse kidney. The transport of gamma-glutamyl amino acids was demonstrated in vitro in studies on kidney slices. Transport was followed by measuring uptake of /sup 35/S after incubation of the slices in media containing gamma-glutamyl methionine (/sup 35/S)sulfone. The experimental complication associated with extracellular conversion of the gamma-glutamyl amino acid to amino acid and uptake of the latter by slices was overcome by using 5-oxoproline formation (catalyzed by intracellular gamma-glutamyl-cyclotransferase) as an indicator of gamma-glutamyl amino acid transport. This method wasmore » also successfully applied to studies on transport of gamma-glutamyl amino acids in vivo. Transport of gamma-glutamyl amino acids in vitro and in vivo is inhibited by several inhibitors of gamma-glutamyl transpeptidase and also by high extracellular levels of glutathione. This seems to explain urinary excretion of gamma-glutamylcystine by humans with gamma-glutamyl transpeptidase deficiency and by mice treated with inhibitors of this enzyme. Mice depleted of glutathione by treatment with buthionine sulfoximine (which inhibits glutathione synthesis) or by treatment with 2,6-dimethyl-2,5-heptadiene-4-one (which effectively interacts with tissue glutathione) exhibited significantly less transport of gamma-glutamyl amino acids than did untreated controls. The findings suggest that intracellular glutathione functions in transport of gamma-glutamyl amino acids. Evidence was also obtained for transport of gamma-glutamyl gamma-glutamylphenylalanine into kidney slices.« less

Effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids in the juice sacs of Satsuma mandarin (Citrus unshiu Marc.) fruit.

PubMed

Matsumoto, Hikaru; Ikoma, Yoshinori

2012-10-03

To elucidate the effect of different postharvest temperatures on the accumulation of sugars, organic acids, and amino acids and to determine the best temperature to minimize their postharvest change, their content after harvest was investigated at 5, 10, 20, and 30 °C for 14 days in the juice sacs of Satsuma mandarin (Citrus unshiu Marc. cv. Aoshima-unshiu) fruit. In all sugars, the changes were negligible at all temperatures. Organic acids decreased slightly at all temperatures, with the exception of malic acid at 30 °C, which increased slightly. Two amino acids, ornithine and glutamine, increased at 5 °C, but they did not increase at other temperatures. In 11 amino acids (phenylalanine, tryptophan, tyrosine, isoleucine, leucine, valine, threonine, lysine, methionine, histidine, and γ-amino butyric acid), the content was higher at 20 and 30 °C than at other temperatures. Thus, the content of amino acids was more variable than that of sugars and organic acids in response to temperatures. Moreover, amino acids responded to temperature differently: two amino acids were cold responsive, and 11 were heat-responsive. The best temperature to minimize the postharvest changes in amino acid profiles in the juice sacs of Aoshima-unshiu was 10 °C. The responsiveness to temperatures in two cold-responsive (ornithine and glutamine) and five heat-responsive (phenylalanine, tryptophan, valine, lysine, and histidine) amino acids was conserved among three different Satsuma mandarin cultivars, Aoshima-unshiu (late-maturing cultivar), Silverhill (midmaturing cultivar), and Miyagawa-wase (early-maturing cultivar). The metabolic responsiveness to temperature stress was discussed on the basis of the changes in the amino acid profile.

Echinococcus granulosus: absorption of cycloleucine and alpha-aminoisobutyric acid by protoscoleces.

PubMed

Jeffs, S A; Arme, C

1986-02-01

Protoscoleces of Echinococcus granulosus absorb the amino acids cycloleucine and alpha-aminoisobutyric acid (AIB) by a combination of mediated uptake and diffusion. After correcting for the latter, values for Kt and Vmax of 0.124 mM and 0.947 nmoles/mg protein/2 min for cycloleucine were calculated; corresponding values for AIB were 0.039 mM and 0.139 nmoles/mg protein/2 min. Both amino acids were accumulated against a concentration gradient and a comparison of Kt and Ki values determined in mutual inhibition experiments suggested that both cycloleucine and AIB share a common uptake locus (loci). Cycloleucine uptake was pH-dependent and could be inhibited by a variety of other amino acids. Neither D- nor L-proline inhibited cycloleucine absorption but D-methionine, D-alanine, D-leucine, D-valine and D-serine were much more effective inhibitors than their L-counterparts.

The development and amino acid binding ability of nano-materials based on azo derivatives: theory and experiment.

PubMed

Shang, Xuefang; Du, Jinge; Yang, Wancai; Liu, Yun; Fu, Zhiyuan; Wei, Xiaofang; Yan, Ruifang; Yao, Ningcong; Guo, Yaping; Zhang, Jinlian; Xu, Xiufang

2014-05-01

Two nano-material-containing azo groups have been designed and developed, and the binding ability of nano-materials with various amino acids has been characterized by UV-vis and fluorescence titrations. Results indicated that two nano-materials showed the strongest binding ability for homocysteine among twenty normal kinds of amino acids (alanine, valine, leucine, isoleucine, methionine, aspartic acid, glutamic acid, arginine, glycine, serine, threonine, asparagine, phenylalanine, histidine, tryptophan, proline, lysine, glutamine, tyrosine and homocysteine). The reason for the high sensitivity for homocysteine was that two nano-materials containing an aldehyde group reacted with SH in homocysteine and afforded very stable thiazolidine derivatives. Theoretical investigation further illustrated the possible binding mode in host-guest interaction and the roles of molecular frontier orbitals in molecular interplay. Thus, the two nano-materials can be used as optical sensors for the detection of homocysteine. Copyright © 2014 Elsevier B.V. All rights reserved.

Requirements of juvenile milkfish (Chanos chanos Forsskal) for essential amino acids.

PubMed

Borlongan, I G; Coloso, R M

1993-01-01

The dietary requirements of juvenile milkfish (Chanos chanos Forsskal) for essential amino acids were determined in a series of experiments. The fish (< or = 8.0 g) were reared in fiber glass tanks provided with flow-through seawater at 28 degrees C and salinity of 32 g/L for 12 wk. In each experiment, a series of amino acid test diets was formulated containing a combination of intact protein sources (casein-gelatin, fish meal-gelatin, fish meal-soybean meal or fish meal-zein) and crystalline amino acids to simulate the levels found in milkfish tissue proteins except for the test amino acid. Each set of isonitrogenous diets contained 40-45% protein and graded levels of the amino acid to be tested. At the end of the feeding experiment, growth, survival and feed efficiency were determined. The requirement level for each essential amino acid was estimated from breakpoint analysis of the growth curve. The dietary essential amino acid requirements (as the percentage of dietary protein) of milkfish juveniles were as follows: arginine, 5.25; histidine, 2.00; isoleucine, 4.00; leucine, 5.11; lysine, 4.00; methionine, 2.50 (cystine, 0.75); phenylalanine, 4.22 (tyrosine, 1.00) or 2.80 (tyrosine, 2.67); threonine, 4.50; tryptophan, 0.60; valine, 3.55. This information is valuable in developing cost-effective practical or commercial feeds and research diets for milkfish juveniles.

Cerebrospinal fluid as a reflector of central cholinergic and amino acid neurotransmitter activity in cerebellar ataxia.

PubMed

Manyam, B V; Giacobini, E; Ferraro, T N; Hare, T A

1990-11-01

Cerebrospinal fluid (CSF) amino acid neurotransmitters, related compounds, and their precursors, choline levels, and acetylcholinesterase activity were measured in the CSF of patients with cerebellar ataxia during a randomized, double-blind, crossover, placebo-controlled clinical trial of physostigmine salicylate. The CSF gamma-aminobutyric acid, methionine, and choline levels, adjusted for age, were significantly lower in patients with cerebellar ataxia compared with controls. Physostigmine selectively reduced the level of CSF isoleucine and elevated the levels of phosphoethanolamine. No change occurred in CSF acetylcholinesterase activity and in the levels of plasma amino compounds in patients with cerebellar ataxia when compared with controls. Median ataxia scores did not statistically differ between placebo and physostigmine nor did functional improvement occur in any of the patients.

Biologically active LIL proteins built with minimal chemical diversity

PubMed Central

Heim, Erin N.; Marston, Jez L.; Federman, Ross S.; Edwards, Anne P. B.; Karabadzhak, Alexander G.; Petti, Lisa M.; Engelman, Donald M.; DiMaio, Daniel

2015-01-01

We have constructed 26-amino acid transmembrane proteins that specifically transform cells but consist of only two different amino acids. Most proteins are long polymers of amino acids with 20 or more chemically distinct side-chains. The artificial transmembrane proteins reported here are the simplest known proteins with specific biological activity, consisting solely of an initiating methionine followed by specific sequences of leucines and isoleucines, two hydrophobic amino acids that differ only by the position of a methyl group. We designate these proteins containing leucine (L) and isoleucine (I) as LIL proteins. These proteins functionally interact with the transmembrane domain of the platelet-derived growth factor β-receptor and specifically activate the receptor to transform cells. Complete mutagenesis of these proteins identified individual amino acids required for activity, and a protein consisting solely of leucines, except for a single isoleucine at a particular position, transformed cells. These surprisingly simple proteins define the minimal chemical diversity sufficient to construct proteins with specific biological activity and change our view of what can constitute an active protein in a cellular context. PMID:26261320

The role of various amino acids in enzymatic browning process in potato tubers, and identifying the browning products.

PubMed

Ali, Hussein M; El-Gizawy, Ahmed M; El-Bassiouny, Rawia E I; Saleh, Mahmoud A

2016-02-01

The effects of five structurally variant amino acids, glycine, valine, methionine, phenylalanine and cysteine were examined as inhibitors and/or stimulators of fresh-cut potato browning. The first four amino acids showed conflict effects; high concentrations (⩾ 100mM for glycine and ⩾ 1.0M for the other three amino acids) induced potato browning while lower concentrations reduced the browning process. Alternatively, increasing cysteine concentration consistently reduced the browning process due to reaction with quinone to give colorless adduct. In PPO assay, high concentrations (⩾ 1.11 mM) of the four amino acids developed more color than that of control samples. Visible spectra indicated a continuous condensation of quinone and glycine to give colored adducts absorbed at 610-630 nm which were separated and identified by LC-ESI-MS as catechol-diglycine adduct that undergoes polymerization with other glycine molecules to form peptide side chains. In lower concentrations, the less concentration the less developed color was observed. Copyright © 2015 Elsevier Ltd. All rights reserved.

Quantitation of Cellular Metabolic Fluxes of Methionine

PubMed Central

Shlomi, Tomer; Fan, Jing; Tang, Baiqing; Kruger, Warren D.; Rabinowitz, Joshua D.

2014-01-01

Methionine is an essential proteogenic amino acid. In addition, it is a methyl donor for DNA and protein methylation and a propylamine donor for polyamine biosyn-thesis. Both the methyl and propylamine donation pathways involve metabolic cycles, and methods are needed to quantitate these cycles. Here, we describe an analytical approach for quantifying methionine metabolic fluxes that accounts for the mixing of intracellular and extracellular methionine pools. We observe that such mixing prevents isotope tracing experiments from reaching the steady state due to the large size of the media pools and hence precludes the use of standard stationary metabolic flux analysis. Our approach is based on feeding cells with 13C methionine and measuring the isotope-labeling kinetics of both intracellular and extracellular methionine by liquid chromatography−mass spectrometry (LC-MS). We apply this method to quantify methionine metabolism in a human fibrosarcoma cell line and study how methionine salvage pathway enzyme methylthioadenosine phosphorylase (MTAP), frequently deleted in cancer, affects methionine metabolism. We find that both transmethylation and propylamine transfer fluxes amount to roughly 15% of the net methionine uptake, with no major changes due to MTAP deletion. Our method further enables the quantification of flux through the pro-tumorigenic enzyme ornithine decarboxylase, and this flux increases 2-fold following MTAP deletion. The analytical approach used to quantify methionine metabolic fluxes is applicable for other metabolic systems affected by mixing of intracellular and extracellular metabolite pools. PMID:24397525

Methionine kinetics in adult men: effects of dietary betaine on L-(2H3-methyl-1-13C)methionine

DOE Office of Scientific and Technical Information (OSTI.GOV)

Storch, K.J.; Wagner, D.A.; Young, V.R.

1991-08-01

The effects of a daily 3-g supplement of betaine on kinetic aspects of L-(2H3-methyl-1-13C)methionine (MET) metabolism in healthy young adult men were explored. Four groups of four subjects each were given a control diet, based on an L-amino acid mixture supplying 29.5 and 21.9 mg.kg-1.d-1 of L-methionine and L-cystine for 4 d before the tracer study, conducted on day 5 during the fed state. Two groups received the control diet and two groups received the betaine supplement. Tracer was given intravenously (iv) or orally. The transmethylation rate of MET (TM), homocysteine remethylation (RM), and oxidation of methionine were estimated frommore » plasma methionine labeling and 13C enrichment of expired air. RM tended to increase (P = 0.14) but the TM and methionine oxidation were significantly (P less than 0.05) higher after betaine supplementation when estimated with the oral tracer. No differences were detected with the intravenous tracer. Methionine concentration in plasma obtained from blood taken from subjects in the fed state was higher (P less than 0.01) with betaine supplementation. These results suggest that excess methyl-group intake may increase the dietary requirement for methionine.« less

Repairing oxidized proteins in the bacterial envelope using respiratory chain electrons.

PubMed

Gennaris, Alexandra; Ezraty, Benjamin; Henry, Camille; Agrebi, Rym; Vergnes, Alexandra; Oheix, Emmanuel; Bos, Julia; Leverrier, Pauline; Espinosa, Leon; Szewczyk, Joanna; Vertommen, Didier; Iranzo, Olga; Collet, Jean-François; Barras, Frédéric

2015-12-17

The reactive species of oxygen and chlorine damage cellular components, potentially leading to cell death. In proteins, the sulfur-containing amino acid methionine is converted to methionine sulfoxide, which can cause a loss of biological activity. To rescue proteins with methionine sulfoxide residues, living cells express methionine sulfoxide reductases (Msrs) in most subcellular compartments, including the cytosol, mitochondria and chloroplasts. Here we report the identification of an enzymatic system, MsrPQ, repairing proteins containing methionine sulfoxide in the bacterial cell envelope, a compartment particularly exposed to the reactive species of oxygen and chlorine generated by the host defence mechanisms. MsrP, a molybdo-enzyme, and MsrQ, a haem-binding membrane protein, are widely conserved throughout Gram-negative bacteria, including major human pathogens. MsrPQ synthesis is induced by hypochlorous acid, a powerful antimicrobial released by neutrophils. Consistently, MsrPQ is essential for the maintenance of envelope integrity under bleach stress, rescuing a wide series of structurally unrelated periplasmic proteins from methionine oxidation, including the primary periplasmic chaperone SurA. For this activity, MsrPQ uses electrons from the respiratory chain, which represents a novel mechanism to import reducing equivalents into the bacterial cell envelope. A remarkable feature of MsrPQ is its capacity to reduce both rectus (R-) and sinister (S-) diastereoisomers of methionine sulfoxide, making this oxidoreductase complex functionally different from previously identified Msrs. The discovery that a large class of bacteria contain a single, non-stereospecific enzymatic complex fully protecting methionine residues from oxidation should prompt a search for similar systems in eukaryotic subcellular oxidizing compartments, including the endoplasmic reticulum.

A dielectric barrier discharge terminally inactivates RNase A by oxidizing sulfur-containing amino acids and breaking structural disulfide bonds

NASA Astrophysics Data System (ADS)

Lackmann, J.-W.; Baldus, S.; Steinborn, E.; Edengeiser, E.; Kogelheide, F.; Langklotz, S.; Schneider, S.; Leichert, L. I. O.; Benedikt, J.; Awakowicz, P.; Bandow, J. E.

2015-12-01

RNases are among the most stable proteins in nature. They even refold spontaneously after heat inactivation, regaining full activity. Due to their stability and universal presence, they often pose a problem when experimenting with RNA. We investigated the capabilities of nonthermal atmospheric-pressure plasmas to inactivate RNase A and studied the inactivation mechanism on a molecular level. While prolonged heating above 90 °C is required for heat inactivating RNase A, direct plasma treatment with a dielectric barrier discharge (DBD) source caused permanent inactivation within minutes. Circular dichroism spectroscopy showed that DBD-treated RNase A unfolds rapidly. Raman spectroscopy indicated methionine modifications and formation of sulfonic acid. A mass spectrometry-based analysis of the protein modifications that occur during plasma treatment over time revealed that methionine sulfoxide formation coincides with protein inactivation. Chemical reduction of methionine sulfoxides partially restored RNase A activity confirming that sulfoxidation is causal and sufficient for RNase A inactivation. Continued plasma exposure led to over-oxidation of structural disulfide bonds. Using antibodies, disulfide bond over-oxidation was shown to be a general protein inactivation mechanism of the DBD. The antibody’s heavy and light chains linked by disulfide bonds dissociated after plasma exposure. Based on their ability to inactivate proteins by oxidation of sulfur-containing amino acids and over-oxidation of disulfide bonds, DBD devices present a viable option for inactivating undesired or hazardous proteins on heat or solvent-sensitive surfaces.

Amino acid metabolism during exercise in trained rats: the potential role of carnitine in the metabolic fate of branched-chain amino acids.

PubMed

Ji, L L; Miller, R H; Nagle, F J; Lardy, H A; Stratman, F W

1987-08-01

The influence of endurance training and an acute bout of exercise on plasma concentrations of free amino acids and the intermediates of branched-chain amino acid (BCAA) metabolism were investigated in the rat. Training did not affect the plasma amino acid levels in the resting state. Plasma concentrations of alanine (Ala), aspartic acid (Asp), asparagine (Asn), arginine (Arg), histidine (His), isoleucine (Ile), leucine (Leu), lysine (Lys), methionine (Met), phenylalanine (Phe), proline (Pro), serine (Ser), threonine (Thr), and valine (Val) were significantly lower, whereas glutamate (Glu), glycine (Gly), ornithine (Orn), tryptophan (Trp), tyrosine (Tyr), creatinine, urea, and ammonia levels were unchanged, after one hour of treadmill running in the trained rats. Plasma concentration of glutamine (Glu), the branched-chain keto acids (BCKA) and short-chain acyl carnitines were elevated with exercise. Ratios of plasma BCAA/BCKA were dramatically lowered by exercise in the trained rats. A decrease in plasma-free carnitine levels was also observed. These data suggest that amino acid metabolism is enhanced by exercise even in the trained state. BCAA may only be partially metabolized within muscle and some of their carbon skeletons are released into the circulation in forms of BCKA and short-chain acyl carnitines.

Sex differences in amino acids lost via sweating could lead to differential susceptibilities to disturbances in nitrogen balance and collagen turnover.

PubMed

Dunstan, R H; Sparkes, D L; Dascombe, B J; Stevens, C J; Murphy, G R; Macdonald, M M; Gottfries, J; Gottfries, C-G; Roberts, T K

2017-08-01

Fluid collected during sweating is enriched with amino acids derived from the skin's natural moisturising factors and has been termed "faux" sweat. Little is known about sex differences in sweat amino acid composition or whether faux sweat amino acid losses affect nitrogen balance. Faux sweat collected by healthy adults (n = 47) after exercise, and at rest by chronic fatigue patients, was analysed for amino acid composition. Healthy females had higher total amino acid concentrations in sweat (10.5 ± 1.2 mM) compared with healthy males (6.9 ± 0.9 mM). Females had higher levels of 13 amino acids in sweat including serine, alanine and glycine. Higher hydroxyproline and proline levels suggested greater collagen turnover in females. Modelling indicated that with conservative levels of exercise, amino acid losses in females via faux sweat were triple than those predicted for urine, whereas in males they were double. It was concluded that females were more susceptible to key amino acid loss during exercise and/or hot conditions. Females reporting chronic fatigue had higher levels of methionine in faux sweat than healthy females. Males reporting chronic fatigue had higher levels of numerous amino acids in faux sweat compared to healthy males. Higher amino acid loss in faux sweat associated with chronic fatigue could contribute to a hypometabolic state. Depending on activity levels, climatic conditions and gender, amino acid losses in sweat and skin leachate could influence daily protein turnover where periods of continuously high turnover could lead to a negative net nitrogen balance.

Cloning and expression of VB12-independent methionine synthase gene responsive to alkaline stress in rice.

PubMed

Xie, Guo-Sheng; Liu, Shen-Kui; Takano, Tetsuo; You, Zong-Bin; Zhang, Duan-Pin

2002-12-01

VB12-independent methionine synthase is present in higher plants, and catalyzes the methylation of C-homocysteine to form methionine, which is very important for methylation reactions and syntheses of polyamines and ethylene. Under the alkaline condition, using cDNA-RAPD method, a new VB12-independent methionine synthase gene has been cloned and characterized for the first time in rice in this study. The results exhibited that, the cDNA gene entailed 2740 bp, had single copy in the rice genome and encoded peptide of 765 amino acids, the peptide showed 92% and 83% identity with that from Mesembryanthemum cystallinum (U84889) and Cathararanthus roseus (X83499), respectively. It enhanced the transcription more greatly after sodium carbonate treatment for 12 h and 24 h than that of sodium chloride treatment, and then obviously reduced in 48 h later, suggesting that it is related to this stress tolerance in rice.

Adult classical homocystinuria requiring parenteral nutrition: Pitfalls and management.

PubMed

Tran, Christel; Bonafé, Luisa; Nuoffer, Jean-Marc; Rieger, Julie; Berger, Mette M

2017-07-25

Homocystinuria due to cystathionine beta synthase (CBS) deficiency presents with a wide clinical spectrum. Treatment by the enteral route aims at reducing homocysteine levels by using vitamin B6, possibly methionine-restricted diet, betaine and/or folate and vitamin B 12 supplementation. Currently no nutritional guidelines exist regarding parenteral nutrition (PN) under acute conditions. Exhaustive literature search was performed, in order to identify the relevant studies describing the pathogenesis and nutritional intervention of adult classical homocystinuria requiring PN. Description of an illustrative case of an adult female with CBS deficiency and intestinal perforation, who required total PN due to contraindication to enteral nutrition. Nutritional management of decompensated classical homocystinuria is complex and currently no recommendation exists regarding PN composition. Amino acid profile and monitoring of total homocysteine concentration are the main tools enabling a precise assessment of the severity of metabolic alterations. In case of contraindication to enteral nutrition, compounded PN will be required, as described in this paper, to ensure adequate low amounts of methionine and others essential amino acids and avoid potentially fatal toxic hypermethioninemia. By reviewing the literature and reporting successful nutritional management of a decompensated CBS deficiency using tailored PN with limited methionine intake and n-3 PUFA addition, we would like to underscore the fact that standard PN solutions are not adapted for CBS deficient critical ill patients: new solutions are required. High methionine levels (>800 μmol/L) being potentially neurotoxic, there is an urgent need to improve our knowledge of acute nutritional therapy. Copyright © 2017 Elsevier Ltd and European Society for Clinical Nutrition and Metabolism. All rights reserved.

Comparison of Free Total Amino Acid Compositions and Their Functional Classifications in 13 Wild Edible Mushrooms.

PubMed

Sun, Liping; Liu, Qiuming; Bao, Changjun; Fan, Jian

2017-02-24

Thirteen popular wild edible mushroom species in Yunnan Province, Boletus bicolor , Boletus speciosus , Boletus sinicus , Boletus craspedius , Boletus griseus , Boletus ornatipes , Xerocomus , Suillus placidus , Boletinus pinetorus , Tricholoma terreum , Tricholomopsis lividipileata , Termitomyces microcarpus , and Amanita hemibapha , were analyzed for their free amino acid compositions by online pre-column derivazation reversed phase high-performance liquid chromatography (RP-HPLC) analysis. Twenty free amino acids, aspartic acid, glutamic acid, serine, glycine, alanine, praline, cysteine, valine, methionine, phenylalanine, isoleucine, leucine, lysine, histidine, threonine, asparagines, glutamine, arginine, tyrosine, and tryptophan, were determined. The total free amino acid (TAA) contents ranged from 1462.6 mg/100 g in B. craspedius to 13,106.2 mg/100 g in T. microcarpus . The different species showed distinct free amino acid profiles. The ratio of total essential amino acids (EAA) to TAA was 0.13-0.41. All of the analyzed species showed high contents of hydrophobic amino acids, at 33%-54% of TAA. Alanine, cysteine, glutamine, and glutamic acid were among the most abundant amino acids present in all species. The results showed that the analyzed mushrooms possessed significant free amino acid contents, which may be important compounds contributing to the typical mushroom taste, nutritional value, and potent antioxidant properties of these wild edible mushrooms. Furthermore, the principal component analysis (PCA) showed that the accumulative variance contribution rate of the first four principal components reached 94.39%. Cluster analysis revealed EAA composition and content might be an important parameter to separate the mushroom species, and T. microcarpus and A. hemibapha showed remarkable EAA content among the 13 species.

D-Amino acid residue in a defensin-like peptide from platypus venom: effect on structure and chromatographic properties

PubMed Central

2005-01-01

The recent discovery that the natriuretic peptide OvCNPb (Ornithorhynchus venom C-type natriuretic peptide B) from platypus (Ornithorynchus anatinus) venom contains a D-amino acid residue suggested that other D-amino-acid-containing peptides might be present in the venom. In the present study, we show that DLP-2 (defensin-like peptide-2), a 42-amino-acid residue polypeptide in the platypus venom, also contains a D-amino acid residue, D-methionine, at position 2, while DLP-4, which has an identical amino acid sequence, has all amino acids in the L-form. These findings were supported further by the detection of isomerase activity in the platypus gland venom extract that converts DLP-4 into DLP-2. In the light of this new information, the tertiary structure of DLP-2 was recalculated using a new structural template with D-Met2. The structure of DLP-4 was also determined in order to evaluate the effect of a D-amino acid at position 2 on the structure and possibly to explain the large retention time difference observed for the two molecules in reverse-phase HPLC. The solution structures of the DLP-2 and DLP-4 are very similar to each other and to the earlier reported structure of DLP-2, which assumed that all amino acids were in the L-form. Our results suggest that the incorporation of the D-amino acid at position 2 has minimal effect on the overall fold in solution. PMID:16033333

B-vitamin deficiency is protective against DSS-induced colitis in mice

USDA-ARS?s Scientific Manuscript database

Vitamin deficiencies are common in patients with inflammatory bowel disease (IBD). Homocysteine (Hcys) is a thrombogenic amino acid produced from methionine (Met) and its increase in IBD patients indicates a disruption of Met metabolism, yet the role of Hcys and Met metabolism in IBD is not well und...

Ontogenetic changes in digestive enzyme activities and the amino acid profile of starry flounder Platichthys stellatus

NASA Astrophysics Data System (ADS)

Song, Zhidong; Wang, Jiying; Qiao, Hongjin; Li, Peiyu; Zhang, Limin; Xia, Bin

2016-09-01

Ontogenetic changes in digestive enzyme activities and the amino acid (AA) profile of starry flounder, Platichthys stellatus, were investigated and limiting amino acids were estimated compared with the essential AA profile between larvae and live food to clarify starry flounder larval nutritional requirements. Larvae were collected at the egg stage and 0, 2, 4, 7, 12, 17, 24 days after hatching (DAH) for analysis. Larvae grew from 1.91 mm at hatching to 12.13 mm at 24 DAH. Trypsin and chymotrypsin activities changed slightly by 4 DAH and then increased significantly 4 DAH. Pepsin activity increased sharply beginning 17 DAH. Lipase activity increased significantly 4 DAH and increased progressively with larval growth. Amylase activity was also detected in newly hatched larvae and increased 7 DAH followed by a gradual decrease. High free amino acid (FAA) content was detected in starry flounder eggs (110.72 mg/g dry weight). Total FAA content dropped to 43.29 mg/g in 4-DAH larvae and then decreased gradually to 13.74 mg/g in 24-DAH larvae. Most FAAs (except lysine and methionine) decreased >50% in 4-DAH larvae compared with those in eggs and then decreased to the lowest values in 24-DAH larvae. Changes in the protein amino acid (PAA) profile were much milder than those observed for FAAs. Most PAAs increased gradually during larval development, except lysine and phenylalanine. The percentages of free threonine, valine, isoleucine, and leucine decreased until the end of the trial, whereas the protein forms of these four AAs followed the opposite trend. A comparison of the essential AA composition of live food (rotifers, Artemia nauplii, and Artemia metanauplii) and larvae suggested that methionine was potentially the first limiting AA. These results may help develop starry flounder larviculture methods by solving the AA imbalance in live food. Moreover, the increased digestive enzyme activities indicate the possibility of introducing artificial compound feed.

The effect of microbial phytase on ileal phosphorus and amino acid digestibility in the broiler chicken.

PubMed

Rutherfurd, S M; Chung, T K; Moughan, P J

2002-09-01

1. The study aimed to assess the effect of a commercially available microbial phytase on phytate phosphorus and total phosphorus content at the terminal ileum as well as true ileal amino acid digestibility. 2. Five diets, each containing a different plant-based feedstuff, were supplemented with microbial phytase and fed, along with a non-supplemented corresponding diet, to 28-d-old broiler chickens, Chromic oxide was used as an indigestible marker. Ileal contents were collected and analysed, along with the diets, for total phosphorus, phytate phosphorus and amino acids. 3. Endogenous phosphorus determined at the terminal ileum was 272 +/- 108 mg/kg food dry matter (mean +/- SE). Endogenous ileal amino acid flows ranged from 58 +/- 10 mg/kg food dry matter for methionine to 568 +/- 47 mg/kg food dry matter for glutamic acid. 4. Supplementation with microbial phytase resulted in a significantly greater phytate P disappearance from the terminal ileum for rice bran (17% units), but not for soyabean meal, maize, wheat or rapeseed meal. Similarly total phosphorus digestibility was significantly (P < 0.05) higher when microbial phytase was added to the rice-bran-based diet but not for any of the other feedstuffs. 5. Amino acid digestibility was significantly greater in the presence of microbial phytase for all the amino acids examined in wheat, for several of the amino acids each in maize and rapeseed meal and for one amino acid in rice bran and soyabean meal. The average increase in amino acid digestibility for those amino acids affected, was 13, 6, 10, 7 and 12% units for wheat, maize, rapeseed meal, rice bran and soyabean meal, respectively. 6. It appears that microbial phytase improves phosphorus digestibility and amino acid digestibility for certain plant-based feedstuffs.

Cellular mechanisms of renal adaptation of sodium dependent sulfate cotransport to altered dietary sulfate in rats.

PubMed

Sagawa, K; DuBois, D C; Almon, R R; Murer, H; Morris, M E

1998-12-01

The renal transport and fractional reabsorption of inorganic sulfate is altered under conditions of sulfate deficiency or excess. The objective of this study was to examine the cellular mechanisms of adaptation of renal sodium/sulfate cotransport after varying dietary intakes of a sulfur containing amino acid, methionine. Female Lewis rats were divided into four groups and fed diets containing various concentrations of methionine (0, 0.3, 0.82 and 2.46%) for 8 days. Urinary excretion rates and renal clearance of sulfate were significantly decreased in the animals fed a 0% methionine diet or a 0.3% methionine diet, and significantly increased in the animals fed a 2.46% methionine diet when evaluated on days 4 and 7. Serum sulfate concentrations were unchanged by diet treatment in all animals. The fractional reabsorption of sulfate was significantly increased in the animals fed the 0% methionine diet and the 0.3% methionine diets, and decreased in the animals fed the 2.46% methionine diet. Increased mRNA and protein levels for the sodium/sulfate transporter (NaSi-1) were found in the kidney cortex following treatment with the 0 and 0.3% methionine diet groups. Sulfate homeostasis by renal reabsorption is maintained by an up-regulation of steady state levels of NaSi-1 mRNA and protein when the diet is low in methionine.

Distribution and composition of dissolved amino acids in seawater at the Yap Trench

NASA Astrophysics Data System (ADS)

Yan, Y.; Xie, L.; Sun, C.; Yang, G.; Ding, H.

2017-12-01

The distributions and compositions of total hydrolyzed amino acids ( THAA) , dissolved combined amino acids ( DCAA) and dissolved free amino acids ( DFAA) were investigated after analyzing seawater samples collected from different depths by CTD and from the sediment-seawater interface by the Jiaolong submersible, at 4 stations located in the Yap Trench in June, 2016. The results showed that the average concentration of THAA was (2.44±0.85) μmol /L, while the average concentrations of DCAA and DFAA were (1.97±0.82) μmol /L and (0.47±0.34)μmol /L, respectively.The concentrations of THAA and DCAA displayed a decreasing trend from surface layer to deep layer. In the vertical distribution, the concentrations of THAA varied differently in superficial layer (above 1000 meters). THAA, DFAA and DCAA had a similar concentrations below 1000 meter depth. In the study area, major constituents of dissolved amino acids were methionine, threonine , histidine, glutamic acid , valine and glycine. At the Yap Trench, neutral dissolved amino acids were dominant in total dissolved amino acids. The trend of vertical distributions of various types of THAA, DFAA, and DCAA were similar with the total THAA, DFAA, and DCAA. In sediment-seawater interface, the seawater in the northwest of the trench has high concentrations of THAA and DCAA, while the concentrations of DFAA were similar in the seawater at the sediment-seawater interface.

Age-dependent increase in ortho-tyrosine and methionine sulfoxide in human skin collagen is not accelerated in diabetes. Evidence against a generalized increase in oxidative stress in diabetes.

PubMed Central

Wells-Knecht, M C; Lyons, T J; McCance, D R; Thorpe, S R; Baynes, J W

1997-01-01

The glycoxidation products Nepsilon-(carboxymethyl)lysine and pentosidine increase in skin collagen with age and at an accelerated rate in diabetes. Their age-adjusted concentrations in skin collagen are correlated with the severity of diabetic complications. To determine the relative roles of increased glycation and/or oxidation in the accelerated formation of glycoxidation products in diabetes, we measured levels of amino acid oxidation products, distinct from glycoxidative modifications of amino acids, as independent indicators of oxidative stress and damage to collagen in aging and diabetes. We show that ortho-tyrosine and methionine sulfoxide are formed in concert with Nepsilon-(carboxymethyl)lysine and pentosidine during glycoxidation of collagen in vitro, and that they also increase with age in human skin collagen. The age-adjusted levels of these oxidized amino acids in collagen was the same in diabetic and nondiabetic subjects, arguing that diabetes per se does not cause an increase in oxidative stress or damage to extracellular matrix proteins. These results provide evidence for an age-dependent increase in oxidative damage to collagen and support previous conclusions that the increase in glycoxidation products in skin collagen in diabetes can be explained by the increase in glycemia alone, without invoking a generalized, diabetes-dependent increase in oxidative stress. PMID:9259583

Tetrahydrofuran Calpha-tetrasubstituted amino acids: two consecutive beta-turns in a crystalline linear tripeptide.

PubMed

Maity, Prantik; Zabel, Manfred; König, Burkhard

2007-10-12

The synthesis of tetrahydrofuran Calpha-tetrasubstituted amino acids (TAAs) and their effect on the conformation in small peptides are reported. The synthesis starts from the protein amino acid methionine, which is protected at the C and N terminus and converted into the corresponding sulfonium salt by alkylation. Simple base treatment in the presence of an aryl aldehyde leads to the formation of tetrahydrofuran tetrasubstituted Calpha-amino acids in a highly diastereoselective (trans/cis ratio up to 97:3) reaction with moderate to good yields (35-78%) depending on the aldehyde used. Palladium-catalyzed coupling reactions allow a subsequent further functionalization of the TAA. The R,S,S-TAA-Ala dipeptide amide adopts a beta-turn type I conformation, whereas its S,R,S isomer does not. The R,S,S-Gly-TAA-Ala tripeptide amide shows in the solid state and in solution a conformation of two consecutive beta-turn type III structures, stabilized by i+3-->i intramolecular hydrogen bonds.

Differential distribution of amino acids in plants.

PubMed

Kumar, Vinod; Sharma, Anket; Kaur, Ravdeep; Thukral, Ashwani Kumar; Bhardwaj, Renu; Ahmad, Parvaiz

2017-05-01

Plants are a rich source of amino acids and their individual abundance in plants is of great significance especially in terms of food. Therefore, it is of utmost necessity to create a database of the relative amino acid contents in plants as reported in literature. Since in most of the cases complete analysis of profiles of amino acids in plants was not reported, the units used and the methods applied and the plant parts used were different, amino acid contents were converted into relative units with respect to lysine for statistical analysis. The most abundant amino acids in plants are glutamic acid and aspartic acid. Pearson's correlation analysis among different amino acids showed that there were no negative correlations between the amino acids. Cluster analysis (CA) applied to relative amino acid contents of different families. Alismataceae, Cyperaceae, Capparaceae and Cactaceae families had close proximity with each other on the basis of their relative amino acid contents. First three components of principal component analysis (PCA) explained 79.5% of the total variance. Factor analysis (FA) explained four main underlying factors for amino acid analysis. Factor-1 accounted for 29.4% of the total variance and had maximum loadings on glycine, isoleucine, leucine, threonine and valine. Factor-2 explained 25.8% of the total variance and had maximum loadings on alanine, aspartic acid, serine and tyrosine. 14.2% of the total variance was explained by factor-3 and had maximum loadings on arginine and histidine. Factor-4 accounted 8.3% of the total variance and had maximum loading on the proline amino acid. The relative content of different amino acids presented in this paper is alanine (1.4), arginine (1.8), asparagine (0.7), aspartic acid (2.4), cysteine (0.5), glutamic acid (2.8), glutamine (0.6), glycine (1.0), histidine (0.5), isoleucine (0.9), leucine (1.7), lysine (1.0), methionine (0.4), phenylalanine (0.9), proline (1.1), serine (1.0), threonine (1.0), tryptophan (0.3), tyrosine (0.7) and valine (1.2).

Rhizobitoxine-induced Chlorosis Occurs in Coincidence with Methionine Deficiency in Soybeans

PubMed Central

Okazaki, Shin; Sugawara, Masayuki; Yuhashi, Ken-Ichi; Minamisawa, Kiwamu

2007-01-01

Background and Aims Rhizobitoxine, produced by the legume symbiont Bradyrhizobium elkanii, inhibits cystathionine-β-lyase (EC 4·4·1·8) in methionine biosynthesis and 1-aminocyclopropane-1-carboxylate synthase (ACC) in ethylene biosynthesis. Rhizobitoxine production by B. elkanii enhances nodulation of host legumes via the inhibition of ethylene synthesis, but causes foliar chlorosis in susceptible soybeans, though how it does so remains to be investigated. The aim of this study was to examine the physiological basis of rhizobitoxine-induced chlorosis in soybeans. Methods Wild-type B. elkanii and a rhizobitoxine-deficient mutant were inoculated in Glycine max ‘Lee’. Thirty days after inoculation, the upper parts of soybean shoots were analysed for amino acid contents. Chlorotic soybeans inoculated with wild-type B. elkanii were treated with methionine and ACC to assess the effects of the chemicals on the chlorosis. Key Results Chlorotic upper shoots of soybeans inoculated with wild-type B. elkanii had a lower methionine content and higher accumulation of the methionine precursors than those with the rhizobitoxine-deficient mutant. In addition, the foliar chlorosis was alleviated by the application of methionine. Conclusions Rhizobitoxine-induced chlorosis occurs in coincidence with methionine deficiency as a result of cystathione-β-lyase inhibition during methionine biosynthesis. PMID:17525098

Peculiarities of one-carbon metabolism in the strict carnivorous cat and the role in feline hepatic lipidosis.

PubMed

Verbrugghe, Adronie; Bakovic, Marica

2013-07-19

Research in various species has indicated that diets deficient in labile methyl groups (methionine, choline, betaine, folate) produce fatty liver and links to steatosis and metabolic syndrome, but also provides evidence of the importance of labile methyl group balance to maintain normal liver function. Cats, being obligate carnivores, rely on nutrients in animal tissues and have, due to evolutionary pressure, developed several physiological and metabolic adaptations, including a number of peculiarities in protein and fat metabolism. This has led to specific and unique nutritional requirements. Adult cats require more dietary protein than omnivorous species, maintain a consistently high rate of protein oxidation and gluconeogenesis and are unable to adapt to reduced protein intake. Furthermore, cats have a higher requirement for essential amino acids and essential fatty acids. Hastened use coupled with an inability to conserve certain amino acids, including methionine, cysteine, taurine and arginine, necessitates a higher dietary intake for cats compared to most other species. Cats also seemingly require higher amounts of several B-vitamins compared to other species and are predisposed to depletion during prolonged inappetance. This carnivorous uniqueness makes cats more susceptible to hepatic lipidosis.

Peculiarities of One-Carbon Metabolism in the Strict Carnivorous Cat and the Role in Feline Hepatic Lipidosis

PubMed Central

Verbrugghe, Adronie; Bakovic, Marica

2013-01-01

Research in various species has indicated that diets deficient in labile methyl groups (methionine, choline, betaine, folate) produce fatty liver and links to steatosis and metabolic syndrome, but also provides evidence of the importance of labile methyl group balance to maintain normal liver function. Cats, being obligate carnivores, rely on nutrients in animal tissues and have, due to evolutionary pressure, developed several physiological and metabolic adaptations, including a number of peculiarities in protein and fat metabolism. This has led to specific and unique nutritional requirements. Adult cats require more dietary protein than omnivorous species, maintain a consistently high rate of protein oxidation and gluconeogenesis and are unable to adapt to reduced protein intake. Furthermore, cats have a higher requirement for essential amino acids and essential fatty acids. Hastened use coupled with an inability to conserve certain amino acids, including methionine, cysteine, taurine and arginine, necessitates a higher dietary intake for cats compared to most other species. Cats also seemingly require higher amounts of several B-vitamins compared to other species and are predisposed to depletion during prolonged inappetance. This carnivorous uniqueness makes cats more susceptible to hepatic lipidosis. PMID:23877091

Changes in monosaccharides, organic acids and amino acids during Cabernet Sauvignon wine ageing based on a simultaneous analysis using gas chromatography-mass spectrometry.

PubMed

Zhang, Xin-Ke; Lan, Yi-Bin; Zhu, Bao-Qing; Xiang, Xiao-Feng; Duan, Chang-Qing; Shi, Ying

2018-01-01

Monosaccharides, organic acids and amino acids are the important flavour-related components in wines. The aim of this article is to develop and validate a method that could simultaneously analyse these compounds in wine based on silylation derivatisation and gas chromatography-mass spectrometry (GC-MS), and apply this method to the investigation of the changes of these compounds and speculate upon their related influences on Cabernet Sauvignon wine flavour during wine ageing. This work presented a new approach for wine analysis and provided more information concerning red wine ageing. This method could simultaneously quantitatively analyse 2 monosaccharides, 8 organic acids and 13 amino acids in wine. A validation experiment showed good linearity, sensitivity, reproducibility and recovery. Multiple derivatives of five amino acids have been found but their effects on quantitative analysis were negligible, except for methionine. The evolution pattern of each category was different, and we speculated that the corresponding mechanisms involving microorganism activities, physical interactions and chemical reactions had a great correlation with red wine flavours during ageing. Simultaneously quantitative analysis of monosaccharides, organic acids and amino acids in wine was feasible and reliable and this method has extensive application prospects. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Macromolecular Synthesis During the Germination of Saccharomyces cerevisiae Spores

PubMed Central

Rousseau, Paul; Halvorson, Harlyn O.

1973-01-01

After the dormancy of Saccharomyces cerevisiae ascospores had been broken, the synthesis of proteins was observed first, followed rapidly by synthesis of ribonucleic acid (RNA) and much later by deoxyribonucleic acid (DNA) synthesis. Phosphoglucomutase activity increased in a periodic (step) fashion, whereas the activity of five other enzymes increased linearly during germination and outgrowth. The rate of synthesis of these enzymes was highest at about the period of DNA replication. The amino acid pools of dormant spores contained high levels of proline, glutamic acid, and histidine. At 2 h after onset of germination, the pools of phenylalanine and methionine had disappeared and the other components had decreased significantly. By 3.5 h, with the exception of proline and cystine, most amino acid pool components had significantly increased. PMID:4570780

Free amino acids in fibromyalgia syndrome: relationship with clinical picture.

PubMed

Ruggiero, Valeria; Mura, Massimiliano; Cacace, Enrico; Era, Benedetta; Peri, Marcella; Sanna, Giuseppina; Fais, Antonella

2017-04-01

The objectives of our study were to evaluate free amino acid (FAA) concentrations in the serum of patients affected by fibromyalgia syndrome (FMS) and to determine the relationships between FAA levels and FMS clinical parameters. Thus, serum amino acid concentrations were quantified (HPLC analysis) in 23 females with fibromyalgia (according to the American College of Rheumatology classification criteria) and 20 healthy females. The results showed significantly higher serum concentrations of aspartate, cysteine, glutamate, glycine, isoleucine, leucine, methionine, ornithine, phenylalanine, sarcosine, serine, taurine, tyrosine and valine in FMS patients vs. healthy controls. Patients with higher Fibromyalgia Impact Questionnaire (FIQ) scores showed increased levels of alanine, glutamine, isoleucine, leucine, phenylalanine, proline and valine. In conclusion, our results indicate an imbalance in some FAAs in FMS patients. Increased Glu is particularly interesting, as it could explain the deficit in monoaminergic transmission involved in pain.

The MET13 Methylenetetrahydrofolate Reductase Gene Is Essential for Infection-Related Morphogenesis in the Rice Blast Fungus Magnaporthe oryzae

PubMed Central

Wang, Hong; Wang, Congcong; Li, Ya; Yue, Xiaofeng; Ma, Zhonghua; Talbot, Nicholas J.; Wang, Zhengyi

2013-01-01

Methylenetetrahydrofolate reductases (MTHFRs) play a key role in the biosynthesis of methionine in both prokaryotic and eukaryotic organisms. In this study, we report the identification of a novel T-DNA-tagged mutant WH672 in the rice blast fungus Magnaporthe oryzae, which was defective in vegetative growth, conidiation and pathogenicity. Analysis of the mutation confirmed a single T-DNA insertion upstream of MET13, which encodes a 626-amino-acid protein encoding a MTHFR. Targeted gene deletion of MET13 resulted in mutants that were non-pathogenic and significantly impaired in aerial growth and melanin pigmentation. All phenotypes associated with Δmet13 mutants could be overcome by addition of exogenous methionine. The M. oryzae genome contains a second predicted MTHFR-encoding gene, MET12. The deduced amino acid sequences of Met13 and Met12 share 32% identity. Interestingly, Δmet12 mutants produced significantly less conidia compared with the isogenic wild-type strain and grew very poorly in the absence of methionine, but were fully pathogenic. Deletion of both genes resulted in Δmet13Δmet12 mutants that showed similar phenotypes to single Δmet13 mutants. Taken together, we conclude that the MTHFR gene, MET13, is essential for infection-related morphogenesis by the rice blast fungus M. oryzae. PMID:24116181

Amino acid composition, score and in vitro protein digestibility of foods commonly consumed in northwest Mexico.

PubMed

Caire-Juvera, Graciela; Vázquez-Ortiz, Francisco A; Grijalva-Haro, Maria I

2013-01-01

A better knowledge of the amino acid composition of foods commonly consumed in different regions is essential to calculate their scores and, therefore, to predict their protein quality. This paper presents the amino acid composition, amino acid score and in vitro protein digestibility of fifteen foods that are commonly consumed in Northwest Mexico. The foods were prepared by the traditional methods and were analyzed by reverse-phase HPLC. The chemical score for each food was determined using the recommendations for children of 1-2 years of age, and the digestibility was evaluated using a multienzyme technique. Lysine was the limiting amino acid in cereal-based products (scores 15 to 54), and methionine and cysteine were limiting in legume products (scores 41 to 47), boiled beef (score = 75) and hamburger (score = 82). The method of preparation had an effect on the content of certain amino acids, some of them increased and others decreased their content. Meat products and regional cheese provided a high amino acid score (scores 67 to 91) and digestibility (80.7 to 87.8%). Bologna, a processed meat product, had a lower digestibility (75.4%). Data on the amino acid composition of foods commonly consumed in Mexico can be used to provide valuable information on food analysis and protein quality, and to contribute to nutrition and health research and health programs. Copyright © AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

New concepts of microbial treatment processes for the nitrogen removal: effect of protein and amino acids degradation.

PubMed

González-Martínez, Alejandro; Calderón, Kadiya; González-López, Jesús

2016-05-01

High concentrations of proteins and amino acids can be found in wastewater and wastewater stream produced in anaerobic digesters, having shown that amino acids could persist over different managements for nitrogen removal affecting the nitrogen removal processes. Nitrogen removal is completely necessary because of their implications and the significant adverse environmental impact of ammonium such as eutrophication and toxicity to aquatic life on the receiving bodies. In the last decade, the treatment of effluents with high ammonium concentration through anammox-based bioprocesses has been enhanced because these biotechnologies are cheaper and more environmentally friendly than conventional technologies. However, it has been shown that the presence of important amounts of proteins and amino acids in the effluents seriously affects the microbial autotrophic consortia leading to important losses in terms of ammonium oxidation efficiency. Particularly the presence of sulfur amino acids such as methionine and cysteine has been reported to drastically decrease the autotrophic denitrification processes as well as affect the microbial community structure promoting the decline of ammonium oxidizing bacteria in favor of other phylotypes. In this context we discuss that new biotechnological processes that improve the degradation of protein and amino acids must be considered as a priority to increase the performance of the autotrophic denitrification biotechnologies.

S-Methylmethionine Conversion to Dimethylsulfoniopropionate: Evidence for an Unusual Transamination Reaction.

PubMed Central

Rhodes, D.; Gage, D. A.; Cooper, AJL.; Hanson, A. D.

1997-01-01

Leaves of Wollastonia biflora (L.) DC. synthesize the osmoprotectant 3-dimethylsulfoniopropionate (DMSP) from methionine via S-methylmethionine (SMM) and 3-dimethylsulfoniopropionaldehyde (DMSP-ald); no other intermediates have been detected. To test whether the amino group of SMM is lost by transamination or deamination, [methyl-2H3,15N]SMM was supplied to leaf discs, and 15N-labeling of amino acids was monitored, along with synthesis of [2H3]DMSP. After short incubations more 15N was incorporated into glutamate than into other amino acids, and the 15N abundance in glutamate exceeded that in the amide group of glutamine (Gln). This is more consistent with transamination than deamination, because deamination would be predicted to give greater labeling of Gln amide N due to reassimilation, via Gln synthetase, of the 15NH4+ released. This prediction was borne out by control experiments with 15NH4Cl. The transamination product of SMM, 4-dimethylsulfonio-2-oxobutyrate (DMSOB), is expected to be extremely unstable. This was confirmed by attempting to synthesize it enzymatically from SMM using L-amino acid oxidase or Gln transaminase K and from 4-methylthio-2-oxobutyrate using methionine S-methyltransferase. In each case, the reaction product decomposed rapidly, releasing dimethylsulfide. The conversion of SMM to DMSP-ald is therefore unlikely to involve a simple transamination that generates free DMSOB. Plausible alternatives are that DMSOB is channeled within a specialized transaminase-decarboxylase complex or that it exists only as the bound intermediate of a single enzyme catalyzing an unusual transamination-decarboxylation reaction. PMID:12223879

The content of protein and of amino acids in Jerusalem artichoke tubers (Helianthus tuberosus L.) of red variety Rote Zonenkugel.

PubMed

Cieślik, Ewa; Gębusia, Agnieszka; Florkiewicz, Adam; Mickowska, Barbara

2011-01-01

Jerusalem artichoke (Helianthus tuberosus L.) is grown primarily for its edible tubers, which were first cultivated by native Americans before the arrival of the Europeans. Unlike most tubers, but in common with other members of the Asteraceae, the tubers store fructans instead of starch. Fructans are non-digestible carbohydrates considered functional food ingredients because they affect body processes in ways that result in better health and in many diseases prevention. However, the Jerusalem artichoke deserves attention not only because of the content of fructans, recent studies also indicate a high protein content, including essential amino acids. The aim of the work was to establish the content of protein and amino acids in Jerusalem artichoke tubers (Helianthus tuberosus L.) of red variety--Rote Zonenkugel. The content of protein was estimated by Dumas method. The amino acids composition was analysed with ion-change chromatography with postcolumn derivatisation and detection of ninhydryn reaction with automatic amino acids analyser. The assessed liophylisate was characterised by high protein content (6.36%) in comparison to chicory (which is the main industrial source of fructans) and to commonly consumed potatoes. There was shown a few times higher content of essential amino acids (also of methionine) in comparison to chicory and potato. The examined essential amino acids were present in very advantagenous proportions. In Jerusalem artichoke tubers of Rote Zonenkugel variety of the high content of protein was established in comparison to other plant sources. The high content was found of amino acids with special stress on essential amino acids (esp. sulphur ones).

Survival time and stability properties of disease-associated prion protein in chronic wasting disease of elk

USDA-ARS?s Scientific Manuscript database

Background: The Rocky Mountain elk (Cervus elaphus nelsoni) prion protein gene exhibits amino acid polymorphism at codon 132, with 132L (leucine) and 132M (methionine) allelic variants present in the population. We have previously shown that following experimental oral challenge with chronic wasting...

Storage proteins of common bean identified with 2D-PAGE

USDA-ARS?s Scientific Manuscript database

The common bean is a significant source of protein, complex carbohydrates, fiber, and minerals. Seeds of most dry beans contain 15 to 25% protein and are rich in lysine but low in the sulfur containing amino acids cysteine and methionine. Knowledge of common bean proteins is important for research a...

Substrate-Tuned Catalysis of the Radical S-Adenosyl-L-Methionine Enzyme NosL Involved in Nosiheptide Biosynthesis.

PubMed

Ji, Xinjian; Li, Yongzhen; Ding, Wei; Zhang, Qi

2015-07-27

NosL is a radical S-adenosyl-L-methionine (SAM) enzyme that converts L-Trp to 3-methyl-2-indolic acid, a key intermediate in the biosynthesis of a thiopeptide antibiotic nosiheptide. In this work we investigated NosL catalysis by using a series of Trp analogues as the molecular probes. Using a benzofuran substrate 2-amino-3-(benzofuran-3-yl)propanoic acid (ABPA), we clearly demonstrated that the 5'-deoxyadenosyl (dAdo) radical-mediated hydrogen abstraction in NosL catalysis is not from the indole nitrogen but likely from the amino group of L-Trp. Unexpectedly, the major product of ABPA is a decarboxylated compound, indicating that NosL was transformed to a novel decarboxylase by an unnatural substrate. Furthermore, we showed that, for the first time to our knowledge, the dAdo radical-mediated hydrogen abstraction can occur from an alcohol hydroxy group. Our study demonstrates the intriguing promiscuity of NosL catalysis and highlights the potential of engineering radical SAM enzymes for novel activities. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Prospects for robust biocatalysis: engineering of novel specificity in a halophilic amino acid dehydrogenase.

PubMed

Munawar, Nayla; Engel, Paul C

2013-01-01

Heat- and solvent-tolerant enzymes from halophiles, potentially important industrially, offer a robust framework for protein engineering, but few solved halophilic structures exist to guide this. Homology modelling has guided mutations in glutamate dehydrogenase (GDH) from Halobacterium salinarum to emulate conversion of a mesophilic GDH to a methionine dehydrogenase. Replacement of K89, A163 and S367 by leucine, glycine and alanine converted halophilic GDH into a dehydrogenase accepting L-methionine, L-norleucine and L-norvaline as substrates. Over-expression in the halophilic expression host Haloferax volcanii and three-step purification gave ~98 % pure protein exhibiting maximum activity at pH 10. This enzyme also showed enhanced thermostability and organic solvent tolerance even at 70 °C, offering a biocatalyst resistant to harsh industrial environments. To our knowledge, this is the first reported amino acid specificity change engineered in a halophilic enzyme, encouraging use of mesophilic models to guide engineering of novel halophilic biocatalysts for industrial application. Calibrated gel filtration experiments show that both the mutant and the wild-type enzyme are stable hexamers.

A critical tyrosine residue determines the uncoupling protein-like activity of the yeast mitochondrial oxaloacetate carrier.

PubMed

Luévano-Martínez, Luis A; Barba-Ostria, Carlos; Araiza-Olivera, Daniela; Chiquete-Félix, Natalia; Guerrero-Castillo, Sergio; Rial, Eduardo; Georgellis, Dimitris; Uribe-Carvajal, Salvador

2012-04-01

The mitochondrial Oac (oxaloacetate carrier) found in some fungi and plants catalyses the uptake of oxaloacetate, malonate and sulfate. Despite their sequence similarity, transport specificity varies considerably between Oacs. Indeed, whereas ScOac (Saccharomyces cerevisiae Oac) is a specific anion-proton symporter, the YlOac (Yarrowia lipolytica Oac) has the added ability to transport protons, behaving as a UCP (uncoupling protein). Significantly, we identified two amino acid changes at the matrix gate of YlOac and ScOac, tyrosine to phenylalanine and methionine to leucine. We studied the role of these amino acids by expressing both wild-type and specifically mutated Oacs in an Oac-null S. cerevisiae strain. No phenotype could be associated with the methionine to leucine substitution, whereas UCP-like activity was dependent on the presence of the tyrosine residue normally expressed in the YlOac, i.e. Tyr-ScOac mediated proton transport, whereas Phe-YlOac lost its protonophoric activity. These findings indicate that the UCP-like activity of YlOac is determined by the tyrosine residue at position 146.

Fragmentation of D- and L-enantiomers of amino acids through interaction with 3He2+ ions

NASA Astrophysics Data System (ADS)

Smirnov, O. V.; Basalaev, A. A.; Boitsov, V. M.; Vyaz'min, S. Yu.; Orbeli, A. L.; Dubina, M. V.

2014-11-01

The relative cross section of processes attendant on the capture of an electron by 12-keV 3He2+ ions are measured by time-of-flight mass spectrometry for leucine (C6H13NO2), methionine (C5H11NO2S), and glutmic acid (C5H9NO4) molecules. No differences between the formation relative cross sections of different fragment ions for the D- and L-enantiomeric forms of the amino acids are revealed. The spectrum of glutamic acid fragments taken at temperatures above 110°C is explained by decomposition of the acid with the formation of pyroglutamic acid (C5H7NO3) and water. The results are compared with published data on fragmentation of the same molecules via electron-impact ionization.

Hypochlorite-induced damage to proteins: formation of nitrogen-centred radicals from lysine residues and their role in protein fragmentation.

PubMed Central

Hawkins, C L; Davies, M J

1998-01-01

Stimulated monocytes and neutrophils generate hypochlorite (HOCl) via the release of the enzyme myeloperoxidase and hydrogen peroxide. HOCl damages proteins by reaction with amino acid side-chains or backbone cleavage. Little information is available about the mechanisms and intermediates involved in these reactions. EPR spin trapping has been employed to identify radicals on proteins, peptides and amino acids after treatment with HOCl. Reaction with HOCl gives both high- and low-molecular-mass nitrogen-centred, protein-derived radicals; the yield of the latter increases with both higher HOCl:protein ratios and enzymic digestion. These radicals, which arise from lysine side-chain amino groups, react with ascorbate, glutathione and Trolox. Reaction of HOCl-treated proteins with excess methionine eliminates radical formation, which is consistent with lysine-derived chloramines (via homolysis of N-Cl bonds) being the radical source. Incubation of HOCl-treated proteins, after removal of excess oxidant, gives rise to both nitrogen-centred radicals, over a period of hours, and time-dependent fragmentation of the protein. Treatment with excess methionine or antioxidants (Trolox, ascorbate, glutathione) protects against fragmentation; urate and bilirubin do not. Chloramine formation and nitrogen-centred radicals are therefore key species in HOCl-induced protein fragmentation. PMID:9620862

Development of a Hypersensitive Periodate-Cleavable Amino Acid that is Methionine- and Disulfide-Compatible and its Application in MHC Exchange Reagents for T Cell Characterisation

PubMed Central

Amore, Alessia; Wals, Kim; Koekoek, Evelyn; Hoppes, Rieuwert; Toebes, Mireille; Schumacher, Ton N M; Rodenko, Boris; Ovaa, Huib

2013-01-01

Incorporation of cleavable linkers into peptides and proteins is of particular value in the study of biological processes. Here we describe the synthesis of a cleavable linker that is hypersensitive to oxidative cleavage as the result of the periodate reactivity of a vicinal amino alcohol moiety. Two strategies directed towards the synthesis of a building block suitable for solid-phase peptide synthesis were developed: a chemoenzymatic route, involving l-threonine aldolase, and an enantioselective chemical route; these led to α,γ-diamino-β-hydroxybutanoic acids in diastereoisomerically mixed and enantiopure forms, respectively. Incorporation of the 1,2-amino alcohol linker into the backbone of a peptide generated a conditional peptide that was rapidly cleaved at very low concentrations of sodium periodate. This cleavable peptide ligand was applied in the generation of MHC exchange reagents for the detection of antigen-specific T cells in peripheral blood cells. The extremely low concentration of periodate required to trigger MHC peptide exchange allowed the co-oxidation of methionine and disulfide residues to be avoided. Conditional MHC reagents hypersensitive to periodate can now be applied without limitations when UV irradiation is undesired or less practical. PMID:23280887

Structure and genetic variability of envelope glycoproteins of two antigenic variants of caprine arthritis-encephalitis lentivirus.

PubMed

Knowles, D P; Cheevers, W P; McGuire, T C; Brassfield, A L; Harwood, W G; Stem, T A

1991-11-01

To define the structure of the caprine arthritis-encephalitis virus (CAEV) env gene and characterize genetic changes which occur during antigenic variation, we sequenced the env genes of CAEV-63 and CAEV-Co, two antigenic variants of CAEV defined by serum neutralization. The deduced primary translation product of the CAEV env gene consists of a 60- to 80-amino-acid signal peptide followed by an amino-terminal surface protein (SU) and a carboxy-terminal transmembrane protein (TM) separated by an Arg-Lys-Lys-Arg cleavage site. The signal peptide cleavage site was verified by amino-terminal amino acid sequencing of native CAEV-63 SU. In addition, immunoprecipitation of [35S]methionine-labeled CAEV-63 proteins by sera from goats immunized with recombinant vaccinia virus expressing the CAEV-63 env gene confirmed that antibodies induced by env-encoded recombinant proteins react specifically with native virion SU and TM. The env genes of CAEV-63 and CAEV-Co encode 28 conserved cysteines and 25 conserved potential N-linked glycosylation sites. Nucleotide sequence variability results in 62 amino acid changes and one deletion within the SU and 34 amino acid changes within the TM.

Structure and genetic variability of envelope glycoproteins of two antigenic variants of caprine arthritis-encephalitis lentivirus.

PubMed Central

Knowles, D P; Cheevers, W P; McGuire, T C; Brassfield, A L; Harwood, W G; Stem, T A

1991-01-01

To define the structure of the caprine arthritis-encephalitis virus (CAEV) env gene and characterize genetic changes which occur during antigenic variation, we sequenced the env genes of CAEV-63 and CAEV-Co, two antigenic variants of CAEV defined by serum neutralization. The deduced primary translation product of the CAEV env gene consists of a 60- to 80-amino-acid signal peptide followed by an amino-terminal surface protein (SU) and a carboxy-terminal transmembrane protein (TM) separated by an Arg-Lys-Lys-Arg cleavage site. The signal peptide cleavage site was verified by amino-terminal amino acid sequencing of native CAEV-63 SU. In addition, immunoprecipitation of [35S]methionine-labeled CAEV-63 proteins by sera from goats immunized with recombinant vaccinia virus expressing the CAEV-63 env gene confirmed that antibodies induced by env-encoded recombinant proteins react specifically with native virion SU and TM. The env genes of CAEV-63 and CAEV-Co encode 28 conserved cysteines and 25 conserved potential N-linked glycosylation sites. Nucleotide sequence variability results in 62 amino acid changes and one deletion within the SU and 34 amino acid changes within the TM. Images PMID:1656067

Characterization of Bacillus thuringiensis l-Isoleucine Dioxygenase for Production of Useful Amino Acids▿†

PubMed Central

Hibi, Makoto; Kawashima, Takashi; Kodera, Tomohiro; Smirnov, Sergey V.; Sokolov, Pavel M.; Sugiyama, Masakazu; Shimizu, Sakayu; Yokozeki, Kenzo; Ogawa, Jun

2011-01-01

We determined the enzymatic characteristics of an industrially important biocatalyst, α-ketoglutarate-dependent l-isoleucine dioxygenase (IDO), which was found to be the enzyme responsible for the generation of (2S,3R,4S)-4-hydroxyisoleucine in Bacillus thuringiensis 2e2. Depending on the amino acid used as the substrate, IDO catalyzed three different types of oxidation reactions: hydroxylation, dehydrogenation, and sulfoxidation. IDO stereoselectively hydroxylated several hydrophobic aliphatic l-amino acids, as well as l-isoleucine, and produced (S)-3-hydroxy-l-allo-isoleucine, 4-hydroxy-l-leucine, (S)-4-hydroxy-l-norvaline, 4-hydroxy-l-norleucine, and 5-hydroxy-l-norleucine. The IDO reaction product of l-isoleucine, (2S,3R,4S)-4-hydroxyisoleucine, was again reacted with IDO and dehydrogenated into (2S,3R)-2-amino-3-methyl-4-ketopentanoate, which is also a metabolite found in B. thuringiensis 2e2. Interestingly, IDO catalyzed the sulfoxidation of some sulfur-containing l-amino acids and generated l-methionine sulfoxide and l-ethionine sulfoxide. Consequently, the effective production of various modified amino acids would be possible using IDO as the biocatalyst. PMID:21821743

Collision-Induced Dissociation of Deprotonated Peptides. Relative Abundance of Side-Chain Neutral Losses, Residue-Specific Product Ions, and Comparison with Protonated Peptides

NASA Astrophysics Data System (ADS)

Liang, Yuxue; Neta, Pedatsur; Yang, Xiaoyu; Stein, Stephen E.

2018-03-01

High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with three to six residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The abundance of losses from the side chains of other amino acids is estimated relative to that of threonine. While some amino acids lose the whole side chain, others lose only part of it, and some exhibit two or more different losses. Side-chain neutral losses are less abundant in the spectra of protonated peptides, being significant mainly for methionine and arginine. In addition to the neutral losses, many amino acid residues in deprotonated peptides produce specific negative ions after peptide bond cleavage. An expanded list of fragment ions from protonated peptides is also presented and compared with those of deprotonated peptides. Fragment ions are mostly different for these two cases. These lists of fragments are used to annotate peptide mass spectral libraries and to aid in the confirmation of specific amino acids in peptides. [Figure not available: see fulltext.

Collision-Induced Dissociation of Deprotonated Peptides. Relative Abundance of Side-Chain Neutral Losses, Residue-Specific Product Ions, and Comparison with Protonated Peptides.

PubMed

Liang, Yuxue; Neta, Pedatsur; Yang, Xiaoyu; Stein, Stephen E

2018-03-01

High-accuracy MS/MS spectra of deprotonated ions of 390 dipeptides and 137 peptides with three to six residues are studied. Many amino acid residues undergo neutral losses from their side chains. The most abundant is the loss of acetaldehyde from threonine. The abundance of losses from the side chains of other amino acids is estimated relative to that of threonine. While some amino acids lose the whole side chain, others lose only part of it, and some exhibit two or more different losses. Side-chain neutral losses are less abundant in the spectra of protonated peptides, being significant mainly for methionine and arginine. In addition to the neutral losses, many amino acid residues in deprotonated peptides produce specific negative ions after peptide bond cleavage. An expanded list of fragment ions from protonated peptides is also presented and compared with those of deprotonated peptides. Fragment ions are mostly different for these two cases. These lists of fragments are used to annotate peptide mass spectral libraries and to aid in the confirmation of specific amino acids in peptides. Graphical Abstract ᅟ.

Screening of Bothrops snake venoms for L-amino acid oxidase activity

DOE Office of Scientific and Technical Information (OSTI.GOV)

Pessati, M.L.; Fontana, J.D.; Guimaraes, M.F.

1995-12-31

Toxins, enzymes, and biologically active peptides are the main components of snake venoms from the genus Bothrops. Following the venom inoculation, the local effects are hemorrhage, edema, and myonecrosis. Nineteen different species of Brazilian Bothrops were screened for protein content and L-amino acid oxidase activity. B. cotiara, formerly found in the South of Brazil, is now threatened with extinction. Its venom contains a highly hemorrhagic fraction and, as expected from the deep yellow color of the corresponding lyophilized powder, a high L-amino acid oxidase (LAO) activity was also characterized. Flavin adenine dinucleotide (FAD) is its associate coenzyme. B. cotiara venommore » LAO catalyzed the oxidative deamination of several L-amino acids, and the best substrates were methionine, leucine, tryptophan, and phenylalanine, hence, its potential application for the use in biosensors for aspartame determination and for the removal of amino acids from plasma. High levels for LAO were also found in other species than B. cotiara. In addition, the technique of isoelectric focusing (IEF) was employed as a powerful tool to study the iso- or multi-enzyme distribution for LAO activity in the B. cotiara snake venom.« less

Furfural Inhibits Growth by Limiting Sulfur Assimilation in Ethanologenic Escherichia coli Strain LY180▿

PubMed Central

Miller, Elliot N.; Jarboe, Laura R.; Turner, Peter C.; Pharkya, Priti; Yomano, Lorraine P.; York, Sean W.; Nunn, David; Shanmugam, K. T.; Ingram, Lonnie O.

2009-01-01

A wide variety of commercial products can be potentially made from monomeric sugars produced by the dilute acid hydrolysis of lignocellulosic biomass. However, this process is accompanied by side products such as furfural that hinder microbial growth and fermentation. To investigate the mechanism of furfural inhibition, mRNA microarrays of an ethanologenic strain of Escherichia coli (LY180) were compared immediately prior to and 15 min after a moderate furfural challenge. Expression of genes and regulators associated with the biosynthesis of cysteine and methionine was increased by furfural, consistent with a limitation of these critical metabolites. This was in contrast to a general stringent response and decreased expression of many other biosynthetic genes. Of the 20 amino acids individually tested as supplements (100 μM each), cysteine and methionine were the most effective in increasing furfural tolerance with serine (precursor of cysteine), histidine, and arginine of lesser benefit. Supplementation with other reduced sulfur sources such as d-cysteine and thiosulfate also increased furfural tolerance. In contrast, supplementation with taurine, a sulfur source that requires 3 molecules of NADPH for sulfur assimilation, was of no benefit. Furfural tolerance was also increased by inserting a plasmid encoding pntAB, a cytoplasmic NADH/NADPH transhydrogenase. Based on these results, a model is proposed for the inhibition of growth in which the reduction of furfural by YqhD, an enzyme with a low Km for NADPH, depletes NADPH sufficiently to limit the assimilation of sulfur into amino acids (cysteine and methionine) by CysIJ (sulfite reductase). PMID:19684179

Methionine supplementation influences melanin-based plumage colouration in Eurasian kestrel, Falco tinnunculus, nestlings.

PubMed

Parejo, Deseada; Silva, Nadia

2009-11-01

The extent to which the expression of melanin-based plumage colouration in birds is genetically or environmentally determined is controversial. Here, we performed a between-nest design supplementation with either the sulphur amino acid dl-methionine or with water to investigate the importance of the non-genetic component of melanin-based plumage colouration in the Eurasian kestrel, Falco tinnunculus. Methionine affects growth and immunity, thus we aimed to modify nestling growth and immunity before feather development. Then, we measured the effect of the experiment on colouration of two melanin-based plumage patches of nestling kestrels. We found that methionine slowed down nestling growth through treatment administration and that nestlings compensated by speeding up their growth later. We did not find any effects of methionine on nestling immunity (i.e. lymphocyte counts, natural antibody levels or complement-mediated immunity). Effects on growth seemed to be mirrored by changes in nestling colouration in the two sexes: methionine-nestlings showed less intense brown plumage on their backs compared with control nestlings. These results provide support for a non-genetic determination of a melanin-based plumage patch in the two sexes of nestling kestrels.

Methionine metabolism in piglets Fed DL-methionine or its hydroxy analogue was affected by distribution of enzymes oxidizing these sources to keto-methionine.

PubMed

Fang, Zhengfeng; Luo, Hefeng; Wei, Hongkui; Huang, Feiruo; Qi, Zhili; Jiang, Siwen; Peng, Jian

2010-02-10

Previous evidence shows that the extensive catabolism of dietary essential amino acids (AA) by the intestine results in decreased availability of these AA for protein synthesis in extraintestinal tissues. This raises the possibility that extraintestinal availability of AA may be improved by supplying the animal with an AA source more of which can bypass the intestine. To test this hypothesis, six barrows (35-day-old, 8.6 +/- 1.4 kg), implanted with arterial, portal, and mesenteric catheters, were fed a DL-methionine (DL-MET) or DL-2-hydroxy-4-methylthiobutyrate (DL-HMTB) diet once hourly and infused intramesenterically with 1% p-amino hippurate. Although the directly available L-MET in DL-MET diet was about 1.2-fold that in DL-HMTB diet, the net portal appearance of L-MET was not different between the two diets. Compared with the low mRNA abundance and low activity of D-2-hydroxy acid dehydrogenase (D-HADH) and l-2-hydroxy acid oxidase (L-HAOX) in the intestine, the high mRNA abundance and high activity of D-AA oxidase (D-AAOX) indicated that the intestine had a relatively higher capacity of D-MET utilization than of dl-HMTB utilization to L-MET synthesis and its subsequent metabolism. However, in contrast to the much lower D-AAOX activity (nmol/g tissue) in the stomach than in the liver and kidney, both d-HADH and L-HAOX activity in the stomach was comparable with those in the liver and/or kidney, indicating the substantial capacity of the stomach to convert DL-HMTB to L-MET. Collectively, the difference in distribution of activity and mRNA abundance of D-AAOX, D-HADH, and L-HAOX in the piglets may offer a biological basis for the similar portal appearance of L-MET between DL-MET and DL-HMTB diets, and thus may provide new important insights into nutritional efficiency of different L-MET sources.

The relative contribution of genes operating in the S-methylmethionine cycle to methionine metabolism in Arabidopsis seeds.

PubMed

Cohen, Hagai; Salmon, Asaf; Tietel, Zipora; Hacham, Yael; Amir, Rachel

2017-05-01

Enzymes operating in the S -methylmethionine cycle make a differential contribution to methionine synthesis in seeds. In addition, mutual effects exist between the S -methylmethionine cycle and the aspartate family pathway in seeds. Methionine, a sulfur-containing amino acid, is a key metabolite in plant cells. The previous lines of evidence proposed that the S-methylmethionine (SMM) cycle contributes to methionine synthesis in seeds where methionine that is produced in non-seed tissues is converted to SMM and then transported via the phloem into the seeds. However, the relative regulatory roles of the S-methyltransferases operating within this cycle in seeds are yet to be fully understood. In the current study, we generated transgenic Arabidopsis seeds with altered expression of three HOMOCYSTEINE S-METHYLTRANSFERASEs (HMTs) and METHIONINE S-METHYLTRANSFERASE (MMT), and profiled them for transcript and metabolic changes. The results revealed that AtHMT1 and AtHMT3, but not AtHMT2 and AtMMT, are the predominant enzymes operating in seeds as altered expression of these two genes affected the levels of methionine and SMM in transgenic seeds. Their manipulations resulted in adapted expression level of genes participating in methionine synthesis through the SMM and aspartate family pathways. Taken together, our findings provide new insights into the regulatory roles of the SMM cycle and the mutual effects existing between the two methionine biosynthesis pathways, highlighting the complexity of the metabolism of methionine and SMM in seeds.

Flavor Compounds in Pixian Broad-Bean Paste: Non-Volatile Organic Acids and Amino Acids.

PubMed

Lin, Hongbin; Yu, Xiaoyu; Fang, Jiaxing; Lu, Yunhao; Liu, Ping; Xing, Yage; Wang, Qin; Che, Zhenming; He, Qiang

2018-05-29

Non-volatile organic acids and amino acids are important flavor compounds in Pixian broad-bean paste, which is a traditional Chinese seasoning product. In this study, non-volatile organic acids, formed in the broad-bean paste due to the metabolism of large molecular compounds, are qualitatively and quantitatively determined by high-performance liquid chromatography (HPLC). Amino acids, mainly produced by hydrolysis of soybean proteins, were determined by the amino acid automatic analyzer. Results indicated that seven common organic acids and eighteen common amino acids were found in six Pixian broad-bean paste samples. The content of citric acid was found to be the highest in each sample, between 4.1 mg/g to 6.3 mg/g, and malic acid were between 2.1 mg/g to 3.6 mg/g ranked as the second. Moreover, fumaric acid was first detected in fermented bean pastes albeit with a low content. For amino acids, savory with lower sour taste including glutamine (Gln), glutamic acid (Glu), aspartic acid (Asp) and asparagines (Asn) were the most abundant, noted to be 6.5 mg/g, 4.0 mg/g, 6.4 mg/g, 4.9 mg/g, 6.2 mg/g and 10.2 mg/g, and bitter taste amino acids followed. More importantly, as important flavor materials in Pixian broad-bean paste, these two groups of substances are expected to be used to evaluate and represent the flavor quality of Pixian broad-bean paste. Moreover, the results revealed that citric acid, glutamic acid, methionine and proline were the most important flavor compounds. These findings are agreat contribution for evaluating the quality and further assessment of Pixian broad-bean paste.

White clover fractions as protein source for monogastrics: dry matter digestibility and protein digestibility-corrected amino acid scores.

PubMed

Stødkilde, Lene; Damborg, Vinni K; Jørgensen, Henry; Laerke, Helle N; Jensen, Søren K

2018-05-01

The present study aimed to evaluate the use of white clover as an alternative protein source for monogastrics. White clover plant and leaves were processed using a screw-press resulting in a solid pulp and a juice from which protein was acid-precipitated. The chemical composition of all fractions was determined and digestibility of dry matter (DM) and protein was assessed in an experiment with growing rats. Protein concentrates were produced with crude protein (CP) contents of 451 g kg -1 and 530 g kg -1 DM for white clover plant and leaves, respectively, and a pulp with CP contents of 313 and 374 g kg -1 DM from plant and leaves, respectively. The amino acid composition ranged from 4.72 to 6.49 g per 16 g of nitrogen (N) for lysine, 1.82-2.6 g per 16 g N for methionine and cysteine, and 3.66-5.24 g per 16 g N for threonine. True faecal digestibility of protein varied from 0.81 to 0.88, whereas DM digestibility was in the range 0.72-0.80. Methionine and cysteine were found to be limiting in all fractions, regardless of the reference group used. A high digestibility of white clover protein was found irrespective of the physical fractionation. Together with a well-balanced amino acid composition, this makes white clover a promising protein source for monogastrics. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Effect of specific amino acids on growth and aflatoxin production by Aspergillus parasiticus and Aspergillus flavus in defined media.

PubMed Central

Payne, G A; Hagler, W M

1983-01-01

Four amino acids were used as sole nitrogen sources or as supplements to ammonium sulfate, and casein and ammonium sulfate were used as sole nitrogen sources to examine their effects on aflatoxin production by Aspergillus parasiticus NRRL 2999 and Aspergillus flavus 3357 grown on synthetic liquid media. In general, when proline, asparagine, casein, and ammonium sulfate were used as sole nitrogen sources, they supported more growth and toxin production than tryptophan or methionine. However, proline stimulated more toxin production per gram of mycelium in stationary cultures than the other nitrogen sources, including the amino acid asparagine, which is generally recognized as supporting good aflatoxin production. The exact responses to individual nitrogen sources were influenced by the species of fungus and whether cultures were stationary or shaken. In shake cultures, but not in stationary cultures, increased growth was generally associated with increased toxin production. PMID:6416168

Effect of essential amino acids on enteroids: Methionine deprivation suppresses proliferation and affects differentiation in enteroid stem cells

DOE Office of Scientific and Technical Information (OSTI.GOV)

Saito, Yuki; Iwatsuki, Ken; Hanyu, Hikaru

We investigated the effects of essential amino acids on intestinal stem cell proliferation and differentiation using murine small intestinal organoids (enteroids) from the jejunum. By selectively removing individual essential amino acids from culture medium, we found that 24 h of methionine (Met) deprivation markedly suppressed cell proliferation in enteroids. This effect was rescued when enteroids cultured in Met deprivation media for 12 h were transferred to complete medium, suggesting that Met plays an important role in enteroid cell proliferation. In addition, mRNA levels of the stem cell marker leucine-rich repeat-containing G protein-coupled receptor 5 (Lgr5) decreased in enteroids grown in Met deprivationmore » conditions. Consistent with this observation, Met deprivation also attenuated Lgr5-EGFP fluorescence intensity in enteroids. In contrast, Met deprivation enhanced mRNA levels of the enteroendocrine cell marker chromogranin A (ChgA) and markers of K cells, enterochromaffin cells, goblet cells, and Paneth cells. Immunofluorescence experiments demonstrated that Met deprivation led to an increase in the number of ChgA-positive cells. These results suggest that Met deprivation suppresses stem cell proliferation, thereby promoting differentiation. In conclusion, Met is an important nutrient in the maintenance of intestinal stem cells and Met deprivation potentially affects cell differentiation. - Highlights: • Met influences the proliferation of enteroids. • Met plays a crucial role in the maintenance of stem cells. • Met deprivation potentially promotes differentiation into secretory cells.« less

Role of Cystathionine β-Lyase in Catabolism of Amino Acids to Sulfur Volatiles by Genetic Variants of Lactobacillus helveticus CNRZ 32▿

PubMed Central

Lee, Won-Jae; Banavara, Dattatreya S.; Hughes, Joanne E.; Christiansen, Jason K.; Steele, James L.; Broadbent, Jeffery R.; Rankin, Scott A.

2007-01-01

Catabolism of sulfur-containing amino acids plays an important role in the development of cheese flavor. During ripening, cystathionine β-lyase (CBL) is believed to contribute to the formation of volatile sulfur compounds (VSCs) such as methanethiol and dimethyl disulfide. However, the role of CBL in the generation of VSCs from the catabolism of specific sulfur-containing amino acids is not well characterized. The objective of this study was to investigate the role of CBL in VSC formation by Lactobacillus helveticus CNRZ 32 using genetic variants of L. helveticus CNRZ 32 including the CBL-null mutant, complementation of the CBL-null mutant, and the CBL overexpression mutant. The formation of VSCs from methionine, cystathionine, and cysteine was determined in a model system using gas chromatography-mass spectrometry with solid-phase microextraction. With methionine as a substrate, CBL overexpression resulted in higher VSC production than that of wild-type L. helveticus CNRZ 32 or the CBL-null mutant. However, there were no differences in VSC production between the wild type and the CBL-null mutant. With cystathionine, methanethiol production was detected from the CBL overexpression variant and complementation of the CBL-null mutant, implying that CBL may be involved in the conversion of cystathionine to methanethiol. With cysteine, no differences in VSC formation were observed between the wild type and genetic variants, indicating that CBL does not contribute to the conversion of cysteine. PMID:17337535

The low-methionine content of vegan diets may make methionine restriction feasible as a life extension strategy.

PubMed

McCarty, Mark F; Barroso-Aranda, Jorge; Contreras, Francisco

2009-02-01

Recent studies confirm that dietary methionine restriction increases both mean and maximal lifespan in rats and mice, achieving "aging retardant" effects very similar to those of caloric restriction, including a suppression of mitochondrial superoxide generation. Although voluntary caloric restriction is never likely to gain much popularity as a pro-longevity strategy for humans, it may be more feasible to achieve moderate methionine restriction, in light of the fact that vegan diets tend to be relatively low in this amino acid. Plant proteins - especially those derived from legumes or nuts - tend to be lower in methionine than animal proteins. Furthermore, the total protein content of vegan diets, as a function of calorie content, tends to be lower than that of omnivore diets, and plant protein has somewhat lower bioavailability than animal protein. Whole-food vegan diets that moderate bean and soy intake, while including ample amounts of fruit and wine or beer, can be quite low in methionine, while supplying abundant nutrition for health (assuming concurrent B12 supplementation). Furthermore, low-fat vegan diets, coupled with exercise training, can be expected to promote longevity by decreasing systemic levels of insulin and free IGF-I; the latter effect would be amplified by methionine restriction - though it is not clear whether IGF-I down-regulation is the sole basis for the impact of low-methionine diets on longevity in rodents.

Replacement value of betaine for DL-methionine in male broiler chicks.

PubMed

Schutte, J B; De Jong, J; Smink, W; Pack, M

1997-02-01

The effect of DL-methionine and betaine supplementation on growth performance of 2,400 male broilers in the age period of 1 to 38 d, and on carcass composition of a subsample of 384 birds was examined. Three dose levels of DL-methionine (0, 0.05, and 0.10%) and two doses of betaine (0 and 0.04%) were supplemented in different combinations to methioninedeficient diets. Two types of diets were fed as starters and growers: either corn-soybean diets or practical diets typical for the Dutch broiler industry. All diets were fortified with 220 ppm choline in order to avoid a deficiency in methyl groups. Increasing DL-methionine supplementation significantly improved daily weight gain and feed conversion efficiency. Supplemental betaine did not affect bird growth. Betaine slightly improved feed conversion in diets without supplemental DL-methionine, but did not affect this parameter in diets with added DL-methionine. Breast meat yield was significantly increased by about 1.5 percentage points by the addition of 0.05% DL-methionine, whereas 0.04% betaine only tended to increase breast meat yield in the range of 0.3 to 0.6 percentage points. The type of diet did not have any effect on the responses obtained. In summary, there was no evidence for betaine to spare DL-methionine as an essential amino acid supplement in broiler diets.

Methionine as a safe and effective novel biorational mosquito larvicide.

PubMed

Weeks, Emma N I; Baniszewski, Julie; Gezan, Salvador A; Allan, Sandra A; Cuda, James P; Stevens, Bruce R

2018-06-11

Mosquito larvicides provide a source-reduction strategy to diminish adult females that bite and potentially spread pathogens. Demands are mounting for new and innovative effective biorational larvicides, due to the development of resistance to some currently utilized mosquito larvicides, undesirable non-target effects, and U.S. Environmental Protection Agency (EPA) restrictions. Methionine is a human nutrient essential amino acid that unexpectedly has been shown to be a valuable safe pest management tool against select insect pests that possess alkaline gut physiology. The present study evaluated larvicidal toxicity of methionine in several pestiferous mosquito (Diptera: Culicidae) genera. Concentration-dependent DL-methionine kinetics assays of survival and pupation were conducted in larvae of Aedes albopictus Skuse, Anopheles quadrimaculatus Say, and Culex tarsalis Coquillett in glass jars. Higher concentrations of DL-methionine yielded 100% mortality for all test species and prevented pupation at a rate equivalent to Bacillus thuringiensis israelensis (Bti) treatments. Concentration kinetics indicated that An. quadrimaculatus was 10-fold more sensitive to DL-methionine than Ae. albopictus and Cx. tarsalis. EPA regulations currently exempt methionine in pesticide formulations applied to agricultural crops. This study demonstrates that methionine is a highly effective mosquito larvicide that can provide a beneficial new biorational, environmentally sustainable tool to control pestiferous mosquitoes. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

In Salmonella enterica, the Gcn5-Related Acetyltransferase MddA (Formerly YncA) Acetylates Methionine Sulfoximine and Methionine Sulfone, Blocking Their Toxic Effects

PubMed Central

Hentchel, Kristy L.

2014-01-01

Protein and small-molecule acylation reactions are widespread in nature. Many of the enzymes catalyzing acylation reactions belong to the Gcn5-related N-acetyltransferase (GNAT; PF00583) family, named after the yeast Gcn5 protein. The genome of Salmonella enterica serovar Typhimurium LT2 encodes 26 GNATs, 11 of which have no known physiological role. Here, we provide in vivo and in vitro evidence for the role of the MddA (methionine derivative detoxifier; formerly YncA) GNAT in the detoxification of oxidized forms of methionine, including methionine sulfoximine (MSX) and methionine sulfone (MSO). MSX and MSO inhibited the growth of an S. enterica ΔmddA strain unless glutamine or methionine was present in the medium. We used an in vitro spectrophotometric assay and mass spectrometry to show that MddA acetylated MSX and MSO. An mddA+ strain displayed biphasic growth kinetics in the presence of MSX and glutamine. Deletion of two amino acid transporters (GlnHPQ and MetNIQ) in a ΔmddA strain restored growth in the presence of MSX. Notably, MSO was transported by GlnHPQ but not by MetNIQ. In summary, MddA is the mechanism used by S. enterica to respond to oxidized forms of methionine, which MddA detoxifies by acetyl coenzyme A-dependent acetylation. PMID:25368301

Placentome Nutrient Transporters and Mammalian Target of Rapamycin Signaling Proteins Are Altered by the Methionine Supply during Late Gestation in Dairy Cows and Are Associated with Newborn Birth Weight.

PubMed

Batistel, Fernanda; Alharthi, Abdulrahman Sm; Wang, Ling; Parys, Claudia; Pan, Yuan-Xiang; Cardoso, Felipe C; Loor, Juan J

2017-09-01

Background: To our knowledge, most research demonstrating a link between maternal nutrition and both fetal growth and offspring development after birth has been performed with nonruminants. Whether such relationships exist in large ruminants is largely unknown. Objective: We aimed to investigate whether increasing the methionine supply during late pregnancy would alter uteroplacental tissue nutrient transporters and mammalian target of rapamycin (mTOR) and their relation with newborn body weight. Methods: Multiparous Holstein cows were used in a randomized complete block design experiment. During the last 28 d of pregnancy, cows were fed a control diet or the control diet plus ethylcellulose rumen-protected methionine (0.9 g/kg dry matter intake) (Mepron; Evonik Nutrition & Care GmbH) to achieve a 2.8:1 ratio of lysine to methionine in the metabolizable protein reaching the small intestine. We collected placentome samples at parturition and used them to assess mRNA and protein expression and the phosphorylation status of mTOR pathway proteins. Results: Newborn body weight was greater in the methionine group than in the control group (44.1 kg and 41.8 kg, respectively; P ≤ 0.05). Increasing the methionine supply also resulted in greater feed intake (15.8 kg/d and 14.6 kg/d), plasma methionine (11.9 μM and 15.3 μM), and plasma insulin (1.16 μg/L and 0.81 μg/L) in cows during late pregnancy. As a result, mRNA expression of genes involved in neutral amino acid transport [solute carrier (SLC) family members SLC3A2 , SLC7A5 , SLC38A1 , and SLC38A10 ], glucose transport [ SLC2A1 , SLC2A3 , and SLC2A4 ], and the mTOR pathway [mechanistic target of rapamycin and ribosomal protein S6 kinase B1] were upregulated ( P ≤ 0.07) in methionine-supplemented cows. Among 6 proteins in the mTOR pathway, increasing the methionine supply led to greater ( P ≤ 0.09) protein expression of α serine-threonine kinase (AKT), phosphorylated (p)-AKT, p-eukaryotic elongation factor 2, and the p-mTOR:mTOR ratio. Conclusion: Supplemental methionine during late gestation increases feed intake and newborn body weight in dairy cows, and this effect may be mediated by alterations in the uteroplacental transport of nondispensable and dispensable amino acids and glucose at least in part through changes in gene transcription and mTOR signaling. © 2017 American Society for Nutrition.

The Pediatric Methionine Requirement Should Incorporate Remethylation Potential and Transmethylation Demands12

PubMed Central

2016-01-01

The metabolic demand for methionine is great in neonates. Indeed, methionine is the only indispensable sulfur amino acid and is required not only for protein synthesis and growth but is also partitioned to a greater extent to transsulfuration for cysteine and taurine synthesis and to >50 transmethylation reactions that serve to methylate DNA and synthesize metabolites, including creatine and phosphatidylcholine. Therefore, the pediatric methionine requirement must accommodate the demands of rapid protein turnover as well as vast nonprotein demands. Because cysteine spares the methionine requirement, it is likely that the dietary provision of transmethylation products can also feasibly spare methionine. However, understanding the requirement of methionine is further complicated because demethylated methionine can be remethylated by the dietary methyl donors folate and betaine (derived from choline). Intakes of dietary methyl donors are highly variable, which is of particular concern for newborns. It has been demonstrated that many populations have enhanced requirements for these nutrients, and nutrient fortification may exacerbate this phenomenon by selecting phenotypes that increase methyl requirements. Moreover, higher transmethylation rates can limit methyl supply and affect other transmethylation reactions as well as protein synthesis. Therefore, careful investigations are needed to determine how remethylation and transmethylation contribute to the methionine requirement. The purpose of this review is to support our hypothesis that dietary methyl donors and consumers can drive methionine availability for protein synthesis and transmethylation reactions. We argue that nutritional strategies in neonates need to ensure that methionine is available to meet requirements for growth as well as for transmethylation products. PMID:27184279

The Pediatric Methionine Requirement Should Incorporate Remethylation Potential and Transmethylation Demands.

PubMed

Robinson, Jason L; Bertolo, Robert F

2016-05-01

The metabolic demand for methionine is great in neonates. Indeed, methionine is the only indispensable sulfur amino acid and is required not only for protein synthesis and growth but is also partitioned to a greater extent to transsulfuration for cysteine and taurine synthesis and to >50 transmethylation reactions that serve to methylate DNA and synthesize metabolites, including creatine and phosphatidylcholine. Therefore, the pediatric methionine requirement must accommodate the demands of rapid protein turnover as well as vast nonprotein demands. Because cysteine spares the methionine requirement, it is likely that the dietary provision of transmethylation products can also feasibly spare methionine. However, understanding the requirement of methionine is further complicated because demethylated methionine can be remethylated by the dietary methyl donors folate and betaine (derived from choline). Intakes of dietary methyl donors are highly variable, which is of particular concern for newborns. It has been demonstrated that many populations have enhanced requirements for these nutrients, and nutrient fortification may exacerbate this phenomenon by selecting phenotypes that increase methyl requirements. Moreover, higher transmethylation rates can limit methyl supply and affect other transmethylation reactions as well as protein synthesis. Therefore, careful investigations are needed to determine how remethylation and transmethylation contribute to the methionine requirement. The purpose of this review is to support our hypothesis that dietary methyl donors and consumers can drive methionine availability for protein synthesis and transmethylation reactions. We argue that nutritional strategies in neonates need to ensure that methionine is available to meet requirements for growth as well as for transmethylation products. © 2016 American Society for Nutrition.

Identification and Characterization of Mutations Conferring Resistance to d-Amino Acids in Bacillus subtilis

PubMed Central

Leiman, Sara A.; Richardson, Charles; Foulston, Lucy; Elsholz, Alexander K. W.; First, Eric A.

2015-01-01

ABSTRACT Bacteria produce d-amino acids for incorporation into the peptidoglycan and certain nonribosomally produced peptides. However, d-amino acids are toxic if mischarged on tRNAs or misincorporated into protein. Common strains of the Gram-positive bacterium Bacillus subtilis are particularly sensitive to the growth-inhibitory effects of d-tyrosine due to the absence of d-aminoacyl-tRNA deacylase, an enzyme that prevents misincorporation of d-tyrosine and other d-amino acids into nascent proteins. We isolated spontaneous mutants of B. subtilis that survive in the presence of a mixture of d-leucine, d-methionine, d-tryptophan, and d-tyrosine. Whole-genome sequencing revealed that these strains harbored mutations affecting tRNATyr charging. Three of the most potent mutations enhanced the expression of the gene (tyrS) for tyrosyl-tRNA synthetase. In particular, resistance was conferred by mutations that destabilized the terminator hairpin of the tyrS riboswitch, as well as by a mutation that transformed a tRNAPhe into a tyrS riboswitch ligand. The most potent mutation, a substitution near the tyrosine recognition site of tyrosyl-tRNA synthetase, improved enzyme stereoselectivity. We conclude that these mutations promote the proper charging of tRNATyr, thus facilitating the exclusion of d-tyrosine from protein biosynthesis in cells that lack d-aminoacyl-tRNA deacylase. IMPORTANCE Proteins are composed of l-amino acids. Mischarging of tRNAs with d-amino acids or the misincorporation of d-amino acids into proteins causes toxicity. This work reports on mutations that confer resistance to d-amino acids and their mechanisms of action. PMID:25733611

Albumin dialysis has a favorable effect on amino acid profile in hepatic encephalopathy.

PubMed

Koivusalo, Anna-Maria; Teikari, Taru; Höckerstedt, Krister; Isoniemi, Helena

2008-12-01

According to one popular theory, hepatic encephalopathy (HE) is partly caused by an imbalance in plasma amino acid levels. The Fischer's ratio between branched chain amino acids (BCAAs) and aromatic amino acids (AAAs) correlates with the degree of HE; the lower Fischer's ratio, the higher the grade of HE. Extra-corporeal liver support systems, like MARS(R)-albumin dialysis (Molecular Adsorbents Recirculating System), can improve HE. The MARS(R) system uses a hyperosmolar albumin circuit to remove both water-soluble and albumin-bound substances. Plasma levels of neuroactive amino acids were analyzed in 82 consecutive patients with life-threatening liver failure admitted to our ICU. All patients fulfilled our indications for MARS treatment and most also fulfilled the criteria for liver transplantation (LTx). In patients with acute liver failure (ALF), as compared to those with acute decompensation of chronic liver failure (AcOChr), levels of leucine and isoleucine were significantly higher before MARS(R) treatment. In all patients, before MARS(R) treatment the higher the grade of HE grade the lower was the Fischer's ratio and higher were the levels of inhibitory neuroactive amino acids. During MARS(R) treatments the Fischer's ratio increased, and the grade of HE decreased. The increase in Fischer's ratio was mainly due to the decrease in AAAs. The plasma levels of neuroactive amino acids, methionine, glutamine, glutamate, histidine and taurine decreased during MARS(R)-treatment. In this study MARS(R)-albumin dialysis had a favorable effect on the plasma amino acid profile of patients with HE.

Alteration in plasma free amino acid levels and its association with gout.

PubMed

Mahbub, M H; Yamaguchi, Natsu; Takahashi, Hidekazu; Hase, Ryosuke; Amano, Hiroki; Kobayashi-Miura, Mikiko; Kanda, Hideyuki; Fujita, Yasuyuki; Yamamoto, Hiroshi; Yamamoto, Mai; Kikuchi, Shinya; Ikeda, Atsuko; Kageyama, Naoko; Nakamura, Mina; Ishimaru, Yasutaka; Sunagawa, Hiroshi; Tanabe, Tsuyoshi

2017-03-16

Studies on the association of plasma-free amino acids with gout are very limited and produced conflicting results. Therefore, we sought to explore and characterize the plasma-free amino acid (PFAA) profile in patients with gout and evaluate its association with the latter. Data from a total of 819 subjects (including 34 patients with gout) undergoing an annual health examination program in Shimane, Japan were considered for this study. Venous blood samples were collected from the subjects and concentrations of 19 plasma amino acids were determined by high-performance liquid chromatography-electrospray ionization-mass spectrometry. Student's t-test was applied for comparison of variables between patient and control groups. The relationships between the presence or absence of gout and individual amino acids were investigated by logistic regression analysis controlling for the effects of potential demographic confounders. Among 19 amino acids, the levels of 10 amino acids (alanine, glycine, isoleucine, leucine, methionine, phenylalanine, proline, serine, tryptophan, valine) differed significantly (P < .001 to .05) between the patient and control groups. Univariate logistic regression analysis revealed that plasma levels of alanine, isoleucine, leucine, phenylalanine, tryptophan and valine had significant positive associations (P < .005 to .05) whereas glycine and serine had significant inverse association (P < .05) with gout. The observed significant changes in PFAA profiles may have important implications for improving our understanding of pathophysiology, diagnosis and prevention of gout. The findings of this study need further confirmation in future large-scale studies involving a larger number of patients with gout.

Leucine and methionine deficiency induce catabolism through non-overlapping mechanisms in rainbow trout (Oncorhynchus mykiss) primary myoblasts

USDA-ARS?s Scientific Manuscript database

Amino acids (AA) have anabolic effects on protein accretion in muscle. In fish it is unknown if this anabolic response is directly attributed to a single AA or a specific AA profile. Therefore, our experimental objective was to determine if AAs or AA profiles regulate protein turnover and growth-r...

Sulfur amino acids and alanine on pyrite (100) by X-ray photoemission spectroscopy: Surface or molecular role?

NASA Astrophysics Data System (ADS)

Sanchez-Arenillas, M.; Galvez-Martinez, S.; Mateo-Marti, E.

2017-08-01

This paper describes the first successful adsorption of the cysteine, cystine, methionine and alanine amino acids on the pyrite (100) surface under ultra-high vacuum conditions with crucial chemical adsorption parameters driving the process. We have demonstrated by X-ray photoemission spectroscopy (XPS) that the surface pretreatment annealing process on pyrite surfaces is a critical parameter driving surface reactivity. The presence of enriched monosulfide species on the pyrite (100) surface favours the amino acid NH2 chemical form, whereas a longer annealing surface pretreatment of over 3 h repairs the sulfur vacancies in the pyrite, enriching disulfide species on the pyrite surface, which promotes NH3+ adsorption due to the sulfur vacancies in the pyrite being replaced by sulfur atom dimers (S22-) on the surface. Furthermore, even if the surface chemistry (monosulfide or disulfide species enrichment) is the main factor promoting a partial conversion from NH2 to NH3+ species, the unique chemical structure of each amino acid provides a particular fingerprint in the process.

The concentration of free amino acids in blood serum of dairy cows with primary ketosis.

PubMed

Marczuk, J; Brodzki, P; Brodzki, A; Kurek, Ł

2018-03-01

Ketosis is a common condition found in the initial stages of lactation in high-yielding dairy cows. The major cause of ketosis is a negative energy balance. During the energy deficiency, proteolysis processes develop parallel to lipolysis. During proteolysis, muscle tissue can be used as a source of amino acid. To date, the participation of amino acids in gluconeogenesis (glucogenic amino acids) and ketogenesis (ketogenic amino acids) has not been determined in detail. This paper presents the study on determination of the parameters of protein and free amino acid metabolism in blood serum of dairy cows with primary ketosis compared to healthy cows. This study contributes to better understanding of the role of amino acids in pathogenesis of ketosis. A total of 30 cows, divided into two groups: experimental (15 cows with ketosis) and control (15 healthy cows), were included in the study. The concentrations of glucose, β-hydroxybutyrate, total protein, albumin, urea, and free amino acids were determined in peripheral blood. Statistically significantly higher concentrations of glutamine, glutamic acid, isoleucine (p≤0.001), and tyrosine (p≤0.05) were found in cows with primary ketosis compared to healthy cows. Significant decrease in the concentrations of asparagine, histidine, methionine, and serine (p≤0.001), alanine, leucine, lysine and proline (p≤0.05) was observed. Significant increase of total ketogenic and glucogenic amino acids (p≤0.05), and an increased ratio of total ketogenic and glucogenic amino acids to total amino acids (p≤0.001) were noted in cows with ketosis. In our study, the changes, in particular observed in amino acid concentration in cows with primary ketosis, indicate its intensive use in both ketogenesis and gluconeogenesis processes. Therefore, a detailed understanding of the role that amino acids play in gluconeogenesis and ketogenesis will improve ketosis diagnostics and monitoring the course of a ketosis episode. Perhaps, the prevention of this disease is possible by balancing the appropriate feed ration in terms of amino acid content. Copyright© by the Polish Academy of Sciences.

Rapid amino acid quantitation with pre-column derivatization; ultra-performance reverse phase liquid chromatography and single quadrupole mass spectrometry.

PubMed

Pretorius, Carel J; McWhinney, Brett C; Sipinkoski, Bilyana; Wilce, Alice; Cox, David; McWhinney, Avis; Ungerer, Jacobus P J

2018-03-01

We optimized a quantitative amino acid method with pre-column derivatization, norvaline (nva) internal standard and reverse phase ultra-performance liquid chromatography by replacing the ultraviolet detector with a single quadrupole mass spectrometer (MS nva ). We used 13 C 15 N isotopically labeled amino acid internal standards and a C18 column with 1.6μm particles to optimize the chromatography and to confirm separation of isobaric compounds (MS lis ). We compared the analytical performance of MS nva with MS lis and the original method (UV nva ) with clinical samples. The chromatography time per sample of MS nva was 8min, detection capabilities were <1μmol/L for most components, intermediate imprecisions at low concentrations were <10% and there was negligible carryover. MS nva was linear up to a total amino acid concentration in a sample of approximately 9500μmol/L. The agreements between most individual amino acids were satisfactory compared to UV nva with the latter prone to outliers and suboptimal quantitation of urinary arginine, aspartate, glutamate and methionine. MS nva reliably detected argnininosuccinate, β-alanine, citrulline and cysteine-s-sulfate. MS nva resulted in a more than fivefold increase in operational efficiency with accurate detection of amino acids and metabolic intermediates in clinical samples. Crown Copyright © 2017. Published by Elsevier B.V. All rights reserved.

Amino-terminal sequence of glycoprotein D of herpes simplex virus types 1 and 2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Eisenberg, R.J.; Long, D.; Hogue-Angeletti, R.

1984-01-01

Glycoprotein D (gD) of herpes simplex virus is a structural component of the virion envelope which stimulates production of high titers of herpes simplex virus type-common neutralizing antibody. The authors caried out automated N-terminal amino acid sequencing studies on radiolabeled preparations of gD-1 (gD of herpes simplex virus type 1) and gD-2 (gD of herpes simplex virus type 2). Although some differences were noted, particularly in the methionine and alanine profiles for gD-1 and gD-2, the amino acid sequence of a number of the first 30 residues of the amino terminus of gD-1 and gD-2 appears to be quite similar.more » For both proteins, the first residue is a lysine. When we compared out sequence data for gD-1 with those predicted by nucleic acid sequencing, the two sequences could be aligned (with one exception) starting at residue 26 (lysine) of the predicted sequence. Thus, the first 25 amino acids of the predicted sequence are absent from the polypeptides isolated from infected cells.« less

The Effect of Copper And Zinc Nanoparticles on the Growth Parameters, Contents of Ascorbic Acid, and Qualitative Composition of Amino Acids and Acylcarnitines in Pistia stratiotes L. (Araceae)

NASA Astrophysics Data System (ADS)

Olkhovych, Olga; Volkogon, Mykola; Taran, Nataliya; Batsmanova, Lyudmyla; Kravchenko, Inna

2016-04-01

The paper covers the research of copper and zinc nanoparticle effect on the content of ascorbic acid, and quantitative and qualitative composition of amino acids and acylcarnitines in Pistia stratiotes L. plants. Plant exposition to copper nanoparticles led to the decrease in (1) the amount of ascorbic acid, (2) the total content of amino acids (by 25 %), and (3) the amount of all studied amino acids except for the glycine amino acid. At this, the amount of 5-oxoproline, arginine, leucine, ornithine, phenylalanine, proline, serine, and tyrosine was two times lower than in control plants. The reduction of the contents of 8 out of 12 investigated acylcarnitines (namely C0, C2, C3, C5, C6, C8, C16, C18:1) was observed in plants under the influence of copper nanoparticles. The result of plants incubation with zinc nanoparticles was the decrease in (1) the amount of ascorbic acid, (2) the total content of amino acids (by 15 %), (3) the content of leucine, methionine, phenylalanine, proline, and tyrosine (more than twice), and (4) the content of 10 acylcarnitines (C0, C2, C3, C4, C5, C10, C16, C18, C18:1, C18:2). The observed reduction in amino acid contents may negatively affect plants adaptive reactions associated with de novo synthesis of stress proteins. At the same time, the decrease in the content of acylcarnitines, responsible for fatty acid transportation, may lead to the changes in the activity and direction of lipid metabolism in plants and reduce plant's ability to use free fatty acids as the oxidation substrate for cell reparation.

Methionine metabolism in Yucatan miniature swine.

PubMed

McBreairty, Laura E

2016-06-01

Methionine is an essential amino acid which when not incorporated into protein, can be converted to S-adenosylmethionine, the universal methyl donor in over 200 transmethylation reactions, which include creatine and phosphatidylcholine (PC) synthesis, as well as deoxyribonucleic acid (DNA) methylation. Following transmethylation, homocysteine is formed, which can be converted to cysteine via transsulfuration or remethylated to methionine by receiving a methyl group from folate or betaine. Changes to methyl group availability in utero can lead to permanent changes in epigenetic patterns of DNA methylation, which has been implicated in "fetal programming", a phenomenon associated with poor nutrition during fetal development that results in low birth weight and disease in later life. It has been shown that programming can also occur in the neonate. Our global objective was to understand how the variability of nutrients involved in methionine metabolism can affect methionine and methyl group availability. We hypothesize that nutrients that converge on methionine metabolism can affect methionine availability for its various functions. In this thesis, we used intrauterine growth restricted (IUGR) piglets to investigate whether a global nutritional insult in utero can lead to a perturbed methionine metabolism. Our results demonstrate that IUGR piglets have a lower capacity to dispose of homocysteine via both transsulfuration and remethylation pathways, as well as a lower incorporation of methyl groups into PC. The second objective of this thesis was to determine whether variation in methionine supply and demand can affect methionine availability. We demonstrated that stimulating either acute or chronic creatine synthesis leads to lower methyl incorporation into protein and PC in pigs. Furthermore, when methionine is limiting, supplementation with either folate or betaine leads to higher methionine availability for protein synthesis. Finally, because creatine is increasingly being utilized as an ergogenic and neuroprotective supplement, we wanted to determine whether provision of the creatine precursor, guanidinoacetate (GAA), could effectively increase tissue creatine stores. We showed that 2.5 weeks of supplementation with GAA is more effective than creatine at increasing hepatic and muscle creatine stores. The results of this thesis demonstrate that the presence of IUGR, an increased demand for creatine synthesis, or the supplementation with remethylation nutrients can each affect methionine availability; all are important when considering neonatal nutrient requirements. Furthermore, although GAA is effective at increasing levels of tissue creatine, higher GAA methylation can limit methionine availability for growth and synthesis of PC.

Nutritional Requirements for Synthesis of Heat-Labile Enterotoxin by Enterotoxigenic Strains of Escherichia coli

PubMed Central

Gilligan, Peter H.; Robertson, Donald C.

1979-01-01

Optimal growth conditions have been established for production of heat-labile enterotoxin (LT) by both porcine and human strains of enterotoxigenic (ENT+) Escherichia coli. There were no unusual growth factor requirements, and some strains produced fairly high levels of LT in a basal salts medium containing 0.5% glucose if the pH was carefully controlled. Several amino acids markedly stimulated LT synthesis when added to the basal salts-glucose medium. Methionine and lysine were the most stimulatory for both human and porcine strains. Either aspartic acid or glutamic acid further enhanced LT synthesis in the presence of methionine and lysine, with aspartic acid being more stimulatory for porcine strains and glutamic acid more stimulatory for human strains. There were no apparent vitamin requirements and no unusual cations needed for toxin synthesis except that Fe3+ was slightly stimulatory for porcine strains. The stimulation by Fe3+ was observed only in the presence of the three amino acids, suggesting that the effect was indirect rather than on toxin synthesis. The carbon source also influenced the yield of LT. Glucose supported maximal synthesis, but other carbon sources which exhibit a high degree of catabolite repression also supported high levels of synthesis. Little or no LT was released below pH 7.0; therefore, because the pH drops during growth from 7.5 to 6.8, even in highly buffered media, it was necessary to adjust the pH to 8.0 to effect complete release of cell-associated toxin. The defined medium containing three amino acids reduced the amount of UV-absorbing material in culture supernatants about fivefold and increased LT activity for various strains from two- to fivefold over a complex Casamino Acids-yeast extract medium. Conditions found to be optimal for synthesis of LT were inhibitory for the heat-stable enterotoxin. PMID:33900

Metabolomic profiling and stable isotope labelling of Trichomonas vaginalis and Tritrichomonas foetus reveal major differences in amino acid metabolism including the production of 2-hydroxyisocaproic acid, cystathionine and S-methylcysteine.

PubMed

Westrop, Gareth D; Wang, Lijie; Blackburn, Gavin J; Zhang, Tong; Zheng, Liang; Watson, David G; Coombs, Graham H

2017-01-01

Trichomonas vaginalis and Tritrichomonas foetus are pathogens that parasitise, respectively, human and bovine urogenital tracts causing disease. Using LC-MS, reference metabolomic profiles were obtained for both species and stable isotope labelling with D-[U-13C6] glucose was used to analyse central carbon metabolism. This facilitated a comparison of the metabolic pathways of T. vaginalis and T. foetus, extending earlier targeted biochemical studies. 43 metabolites, whose identities were confirmed by comparison of their retention times with authentic standards, occurred at more than 3-fold difference in peak intensity between T. vaginalis and T. foetus. 18 metabolites that were removed from or released into the medium during growth also showed more than 3-fold difference between the species. Major differences were observed in cysteine and methionine metabolism in which homocysteine, produced as a bi-product of trans-methylation, is catabolised by methionine γ-lyase in T. vaginalis but converted to cystathionine in T. foetus. Both species synthesise methylthioadenosine by an unusual mechanism, but it is not used as a substrate for methionine recycling. T. vaginalis also produces and exports high levels of S-methylcysteine, whereas only negligible levels were found in T. foetus which maintains significantly higher intracellular levels of cysteine. 13C-labeling confirmed that both cysteine and S-methylcysteine are synthesised by T. vaginalis; S-methylcysteine can be generated by recombinant T. vaginalis cysteine synthase using phosphoserine and methanethiol. T. foetus contained higher levels of ornithine and citrulline than T. vaginalis and exported increased levels of putrescine, suggesting greater flux through the arginine dihydrolase pathway. T. vaginalis produced and exported hydroxy acid derivatives of certain amino acids, particularly 2-hydroxyisocaproic acid derived from leucine, whereas negligible levels of these metabolites occurred in T. foetus.

Metabolomic profiling and stable isotope labelling of Trichomonas vaginalis and Tritrichomonas foetus reveal major differences in amino acid metabolism including the production of 2-hydroxyisocaproic acid, cystathionine and S-methylcysteine

PubMed Central

Wang, Lijie; Blackburn, Gavin J.; Zhang, Tong; Zheng, Liang; Watson, David G.; Coombs, Graham H.

2017-01-01

Trichomonas vaginalis and Tritrichomonas foetus are pathogens that parasitise, respectively, human and bovine urogenital tracts causing disease. Using LC-MS, reference metabolomic profiles were obtained for both species and stable isotope labelling with D-[U-13C6] glucose was used to analyse central carbon metabolism. This facilitated a comparison of the metabolic pathways of T. vaginalis and T. foetus, extending earlier targeted biochemical studies. 43 metabolites, whose identities were confirmed by comparison of their retention times with authentic standards, occurred at more than 3-fold difference in peak intensity between T. vaginalis and T. foetus. 18 metabolites that were removed from or released into the medium during growth also showed more than 3-fold difference between the species. Major differences were observed in cysteine and methionine metabolism in which homocysteine, produced as a bi-product of trans-methylation, is catabolised by methionine γ-lyase in T. vaginalis but converted to cystathionine in T. foetus. Both species synthesise methylthioadenosine by an unusual mechanism, but it is not used as a substrate for methionine recycling. T. vaginalis also produces and exports high levels of S-methylcysteine, whereas only negligible levels were found in T. foetus which maintains significantly higher intracellular levels of cysteine. 13C-labeling confirmed that both cysteine and S-methylcysteine are synthesised by T. vaginalis; S-methylcysteine can be generated by recombinant T. vaginalis cysteine synthase using phosphoserine and methanethiol. T. foetus contained higher levels of ornithine and citrulline than T. vaginalis and exported increased levels of putrescine, suggesting greater flux through the arginine dihydrolase pathway. T. vaginalis produced and exported hydroxy acid derivatives of certain amino acids, particularly 2-hydroxyisocaproic acid derived from leucine, whereas negligible levels of these metabolites occurred in T. foetus. PMID:29267346

Dose-dependent effects of higher methionine levels on the transcriptome and metabolome of transgenic Arabidopsis seeds.

PubMed

Cohen, Hagai; Amir, Rachel

2017-05-01

Higher methionine levels in transgenic Arabidopsis seeds trigger the accumulation of stress-related transcripts and primary metabolites. These responses depend on the levels of methionine within seeds. Methionine, a sulfur-containing amino acid, is a key metabolite in plant cells. To reveal the regulatory role of the Arabidopsis thaliana CYSTATHIONINE γ-SYNTHASE (AtCGS), methionine main regulatory enzyme, in the synthesis of methionine in seeds, we generated transgenic RNAi seeds with targeted repression of AtCGS during late developmental stages of seeds. Unexpectedly, these seeds accumulated 2.5-fold more methionine than wild-type seeds. To study the nature of these seeds, transcriptomic and primary metabolite profiling were employed using Affymetrix ATH1 microarray and gas chromatography-mass spectrometry analyses, respectively. The results were compared to transgenic Arabidopsis seeds expressing a feedback-insensitive form of AtCGS (named SSE-AtD-CGS) that were previously showed to accumulate up to sixfold more soluble methionine than wild-type seeds. Statistical assessments showed that the nature of transcriptomic and metabolic changes that occurred in RNAi::AtCGS seeds were relatively similar, but to lesser extents, to those previously reported for SSE-AtD-CGS seeds, and linked to the induction of global transcriptomic and metabolic responses associated with stronger desiccation stress. As transgenic seeds obtained by both manipulations exhibited higher, but different methionine levels, the data strongly suggest that these changes depend on the absolute amounts of methionine within seeds and much less to the expression level of AtCGS.

Measurements of mass attenuation coefficient, effective atomic number and electron density of some amino acids

NASA Astrophysics Data System (ADS)

Kore, Prashant S.; Pawar, Pravina P.

2014-05-01

The mass attenuation coefficients of some amino acids, such as DL-aspartic acid-LR(C4H7NO4), L-glutamine (C4H10N2O3), creatine monohydrate LR(C4H9N3O2H2O), creatinine hydrochloride (C4H7N3O·HCl) L-asparagine monohydrate(C4H9N3O2H2O), L-methionine LR(C5H11NO2S), were measured at 122, 356, 511, 662, 1170, 1275 and 1330 keV photon energies using a well-collimated narrow beam good geometry set-up. The gamma-rays were detected using NaI (Tl) scintillation detection system with a resolution of 0.101785 at 662 keV. The attenuation coefficient data were then used to obtain the effective atomic numbers (Zeff), and effective electron densities (Neff) of amino acids. It was observed that the effective atomic number (Zeff) and effective electron densities (Neff) initially decrease and tend to be almost constant as a function of gamma-ray energy. Zeff and Neff experimental values showed good agreement with the theoretical values with less than 1% error for amino acids.

Proximate composition, amino acid and fatty acid profiles of marine snail Rapana venosa meat, visceral mass and operculum.

PubMed

Luo, Fenglei; Xing, Ronge; Wang, Xueqin; Peng, Quancai; Li, Pengcheng

2017-12-01

Rapana venosa (Rv), an important marine snail, demonstrates an increasing nutritional and economic importance. However, there is still limited information available on their nutritional composition. The present study highlights and provides new information on the proximate composition, amino acid and fatty acid profiles of different body parts of Rv, aiming for its better application and research. The operculum contained a high amount of protein and flavor amino acids. The edible tissues, including meat and visceral mass, were valuable sources of essential amino acids (EAA) apart from methionine and cysteine. In addition, the meat contained high amount of taurine. Fatty acid analysis indicated that the edible tissues contained high amounts of ω3 fatty acids, especially eicosapentaenoic acid (EPA) (C20:5ω3) and docosahexaenoic acid (DHA) (C22:6ω3), and had a low ω6/ω3 fatty acid ratio. Interestingly, significantly higher concentrations of most nutritional elements such as fat, EAA, EPA and DHA, were found in the visceral mass compared to those in the meat. The operculum of Rv may became a very interesting source for some protein and flavor peptide development, and the edible parts of Rv may be utilized for special dietary applications requiring high amounts of taurine, EPA, DHA and a lower ω6/ω3 fatty acid ratio. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Emerging perspectives on essential amino acid metabolism in obesity and the insulin-resistant state.

PubMed

Adams, Sean H

2011-11-01

Dysregulation of insulin action is most often considered in the context of impaired glucose homeostasis, with the defining feature of diabetes mellitus being elevated blood glucose concentration. Complications arising from the hyperglycemia accompanying frank diabetes are well known and epidemiological studies point to higher risk toward development of metabolic disease in persons with impaired glucose tolerance. Although the central role of proper blood sugar control in maintaining metabolic health is well established, recent developments have begun to shed light on associations between compromised insulin action [obesity, prediabetes, and type 2 diabetes mellitus (T2DM)] and altered intermediary metabolism of fats and amino acids. For amino acids, changes in blood concentrations of select essential amino acids and their derivatives, in particular BCAA, sulfur amino acids, tyrosine, and phenylalanine, are apparent with obesity and insulin resistance, often before the onset of clinically diagnosed T2DM. This review provides an overview of these changes and places recent observations from metabolomics research into the context of historical reports in the areas of biochemistry and nutritional biology. Based on this synthesis, a model is proposed that links the FFA-rich environment of obesity/insulin resistance and T2DM with diminution of BCAA catabolic enzyme activity, changes in methionine oxidation and cysteine/cystine generation, and tissue redox balance (NADH/NAD+).

Adaptive antioxidant methionine accumulation in respiratory chain complexes explains the use of a deviant genetic code in mitochondria.

PubMed

Bender, Aline; Hajieva, Parvana; Moosmann, Bernd

2008-10-28

Humans and most other animals use 2 different genetic codes to translate their hereditary information: the standard code for nuclear-encoded proteins and a modern variant of this code in mitochondria. Despite the pivotal role of the genetic code for cell biology, the functional significance of the deviant mitochondrial code has remained enigmatic since its first description in 1979. Here, we show that profound and functionally beneficial alterations on the encoded protein level were causative for the AUA codon reassignment from isoleucine to methionine observed in most mitochondrial lineages. We demonstrate that this codon reassignment leads to a massive accumulation of the easily oxidized amino acid methionine in the highly oxidative inner mitochondrial membrane. This apparently paradoxical outcome can yet be smoothly settled if the antioxidant surface chemistry of methionine is taken into account, and we present direct experimental evidence that intramembrane accumulation of methionine exhibits antioxidant and cytoprotective properties in living cells. Our results unveil that methionine is an evolutionarily selected antioxidant building block of respiratory chain complexes. Collective protein alterations can thus constitute the selective advantage behind codon reassignments, which authenticates the "ambiguous decoding" hypothesis of genetic code evolution. Oxidative stress has shaped the mitochondrial genetic code.

RP-HPLC method using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate incorporated with normalization technique in principal component analysis to differentiate the bovine, porcine and fish gelatins.

PubMed

Azilawati, M I; Hashim, D M; Jamilah, B; Amin, I

2015-04-01

The amino acid compositions of bovine, porcine and fish gelatin were determined by amino acid analysis using 6-aminoquinolyl-N-hydroxysuccinimidyl carbamate as derivatization reagent. Sixteen amino acids were identified with similar spectral chromatograms. Data pre-treatment via centering and transformation of data by normalization were performed to provide data that are more suitable for analysis and easier to be interpreted. Principal component analysis (PCA) transformed the original data matrix into a number of principal components (PCs). Three principal components (PCs) described 96.5% of the total variance, and 2 PCs (91%) explained the highest variances. The PCA model demonstrated the relationships among amino acids in the correlation loadings plot to the group of gelatins in the scores plot. Fish gelatin was correlated to threonine, serine and methionine on the positive side of PC1; bovine gelatin was correlated to the non-polar side chains amino acids that were proline, hydroxyproline, leucine, isoleucine and valine on the negative side of PC1 and porcine gelatin was correlated to the polar side chains amino acids that were aspartate, glutamic acid, lysine and tyrosine on the negative side of PC2. Verification on the database using 12 samples from commercial products gelatin-based had confirmed the grouping patterns and the variables correlations. Therefore, this quantitative method is very useful as a screening method to determine gelatin from various sources. Copyright © 2014 Elsevier Ltd. All rights reserved.

Influence of low-molecular-weight glutenin subunit haplotypes on dough rheology and baking quality in elite common wheat varieties

USDA-ARS?s Scientific Manuscript database

The low molecular weight glutenin subunits (LMW-GSs) are a class of wheat seed storage proteins directly involved in the formation of gluten. Depending on the first amino acid residue of the mature proteins, the LMW-GSs are divided into methionine, serine or isoleucine type. These proteins are encod...

Allergenicity, trypsin inhibitor activity and nutritive quality of enzymatically modified soy proteins.

PubMed

De La Barca, Ana María Calderón; Wall, Abraham; López-Díaz, José Alberto

2005-05-01

Two ultrafiltered soy flour protein fractions were evaluated; the first was obtained by hydrolysis (0.5-3 kDa, F(0.5-3)), and the second was an enzymatically methionine-enriched fraction (1-10 kDa, F(1-10)E). Amino acid profiles, protein quality, allergenicity (against soy-sensitive infant sera) and trypsin inhibitor activity were determined. Fraction F(1-10)E fulfilled amino acid requirements for infants, whereas the F(0.5-3) fraction was methionine deficient. Both fractions were similar in net protein utilization, and F(1-10)E digestibility was comparable with casein and higher (P?

Development and validation of a hydrophilic interaction chromatography-mass spectrometry assay for taurine and methionine in matrices rich in carbohydrates.

PubMed

de Person, Marine; Hazotte, Aurélie; Elfakir, Claire; Lafosse, Michel

2005-07-22

A new procedure based on hydrophilic interaction chromatography coupled to tandem mass spectrometry (ionisation process by pneumatically assisted electrospray in negative ion mode), is developed and validated for the simultaneous determination of underivatised taurine and methionine in beverages rich in carbohydrates such as energy drinks. No initial clean-up procedure and no sample derivatisation are required. Satisfactory analysis was obtained on an Astec apHera NH2 (150 mm x 4.6 mm; 5 microm) column with methanol-water (60/40) as mobile phase. The method was validated in terms of specificity, detection limits, linearity, accuracy, precision and stability, using threonine as internal standard. The potential effects of matrix and endogenous amino acid content were also examined. The limits of detection in the beverage varied from 20 microg L(-1) for taurine to 50 micro L(-1) for methionine.

Effect of proteolysis index level on instrumental adhesiveness, free amino acids content and volatile compounds profile of dry-cured ham.

PubMed

Pérez-Santaescolástica, C; Carballo, J; Fulladosa, E; Garcia-Perez, José V; Benedito, J; Lorenzo, J M

2018-05-01

Defective textures in dry-cured ham are a common problem that causes important economic losses in the ham industry. An increase of proteolysis during the dry-cured ham processing may lead to high adhesiveness and consumer rejection of the product. Therefore, the influence of proteolysis index (PI) on instrumental adhesiveness, free amino acids and volatile profile of dry-cured ham was assessed. Two hundred Spanish dry-cured ham units were firstly classified according to their PI: low PI (<32%), medium PI (32-36%) and high PI (>36%). Instrumental adhesiveness was affected by PI, showing the lowest values in the batch with low PI. Significant differences (P < 0.05) among groups were found in six amino acids: serine, taurine, cysteine, methionine, isoleucine and leucine. The content of leucine, serine, methionine, and isoleucine significantly (P < 0.05) increased as the proteolysis index rose. However, taurine and cysteine content showed an opposite behaviour, reaching the highest values in the dry-cured hams with low PI. Significant differences (P < 0.001) in the total content of volatile compounds among ham groups were observed, with the highest concentration in the batch with low PI, and decreasing the concentration as the PI increased. Regarding the different chemical families of volatiles, the hydrocarbons (the main family), alcohols, aldehydes, ketones and acids were more abundant in the hams showing the lowest PI. Esters did not show significant differences among the three batches of hams studied. The present study demonstrated that, apart from the effect on the adhesiveness, an excessive proteolysis seems to be associated with negative effects on the taste and aroma of the dry-cured ham. Copyright © 2018 Elsevier Ltd. All rights reserved.

Enhanced Biocide Treatments with D-amino Acid Mixtures against a Biofilm Consortium from a Water Cooling Tower.

PubMed

Jia, Ru; Li, Yingchao; Al-Mahamedh, Hussain H; Gu, Tingyue

2017-01-01

Different species of microbes form mixed-culture biofilms in cooling water systems. They cause microbiologically influenced corrosion (MIC) and biofouling, leading to increased operational and maintenance costs. In this work, two D-amino acid mixtures were found to enhance two non-oxidizing biocides [tetrakis hydroxymethyl phosphonium sulfate (THPS) and NALCO 7330 (isothiazoline derivatives)] and one oxidizing biocide [bleach (NaClO)] against a biofilm consortium from a water cooling tower in lab tests. Fifty ppm (w/w) of an equimass mixture of D-methionine, D-leucine, D-tyrosine, D-tryptophan, D-serine, D-threonine, D-phenylalanine, and D-valine (D8) enhanced 15 ppm THPS and 15 ppm NALCO 7330 with similar efficacies achieved by the 30 ppm THPS alone treatment and the 30 ppm NALCO 7330 alone treatment, respectively in the single-batch 3-h biofilm removal test. A sequential treatment method was used to enhance bleach because D-amino acids react with bleach. After a 4-h biofilm removal test, the sequential treatment of 5 ppm bleach followed by 50 ppm D8 achieved extra 1-log reduction in sessile cell counts of acid producing bacteria, sulfate reducing bacteria, and general heterotrophic bacteria compared with the 5 ppm bleach alone treatment. The 10 ppm bleach alone treatment showed a similar efficacy with the sequential treatment of 5 ppm bleach followed by 50 ppm D8. The efficacy of D8 was found better than that of D4 (an equimass mixture of D-methionine, D-leucine, D-tyrosine, and D-tryptophan) in the enhancement of the three individual biocides against the biofilm consortium.

Enhanced Biocide Treatments with D-amino Acid Mixtures against a Biofilm Consortium from a Water Cooling Tower

PubMed Central

Jia, Ru; Li, Yingchao; Al-Mahamedh, Hussain H.; Gu, Tingyue

2017-01-01

Different species of microbes form mixed-culture biofilms in cooling water systems. They cause microbiologically influenced corrosion (MIC) and biofouling, leading to increased operational and maintenance costs. In this work, two D-amino acid mixtures were found to enhance two non-oxidizing biocides [tetrakis hydroxymethyl phosphonium sulfate (THPS) and NALCO 7330 (isothiazoline derivatives)] and one oxidizing biocide [bleach (NaClO)] against a biofilm consortium from a water cooling tower in lab tests. Fifty ppm (w/w) of an equimass mixture of D-methionine, D-leucine, D-tyrosine, D-tryptophan, D-serine, D-threonine, D-phenylalanine, and D-valine (D8) enhanced 15 ppm THPS and 15 ppm NALCO 7330 with similar efficacies achieved by the 30 ppm THPS alone treatment and the 30 ppm NALCO 7330 alone treatment, respectively in the single-batch 3-h biofilm removal test. A sequential treatment method was used to enhance bleach because D-amino acids react with bleach. After a 4-h biofilm removal test, the sequential treatment of 5 ppm bleach followed by 50 ppm D8 achieved extra 1-log reduction in sessile cell counts of acid producing bacteria, sulfate reducing bacteria, and general heterotrophic bacteria compared with the 5 ppm bleach alone treatment. The 10 ppm bleach alone treatment showed a similar efficacy with the sequential treatment of 5 ppm bleach followed by 50 ppm D8. The efficacy of D8 was found better than that of D4 (an equimass mixture of D-methionine, D-leucine, D-tyrosine, and D-tryptophan) in the enhancement of the three individual biocides against the biofilm consortium. PMID:28861053

Technical Note: Methionine, a precursor of methane in living plants

NASA Astrophysics Data System (ADS)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2015-03-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued not only about their contribution to the global methane budget but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds to be identified. We made use of stable isotope techniques to verify the in vivo formation of methane, and, in order to identify the carbon precursor, 13C positionally labeled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labeled methionine clearly identified the sulfur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Technical note: Methionine, a precursor of methane in living plants

NASA Astrophysics Data System (ADS)

Lenhart, K.; Althoff, F.; Greule, M.; Keppler, F.

2014-11-01

When terrestrial plants were identified as producers of the greenhouse gas methane, much discussion and debate ensued, not only about their contribution to the global methane budget, but also with regard to the validity of the observation itself. Although the phenomenon has now become more accepted for both living and dead plants, the mechanism of methane formation in living plants remains to be elucidated and its precursor compounds identified. We made use of stable isotope techniques to verify in vivo formation of methane and, in order to identify the carbon precursor, 13C-positionally labelled organic compounds were employed. Here we show that the amino acid L-methionine acts as a methane precursor in living plants. Employing 13C-labelled methionine clearly identified the sulphur-bound methyl group of methionine as a carbon precursor of methane released from lavender (Lavandula angustifolia). Furthermore, when lavender plants were stressed physically, methane release rates and the stable carbon isotope values of the emitted methane greatly increased. Our results provide additional support that plants possess a mechanism for methane production and suggest that methionine might play an important role in the formation of methane in living plants, particularly under stress conditions.

Mouse d-Amino-Acid Oxidase: Distribution and Physiological Substrates

PubMed Central

Koga, Reiko; Miyoshi, Yurika; Sakaue, Hiroaki; Hamase, Kenji; Konno, Ryuichi

2017-01-01

d-Amino-acid oxidase (DAO) catalyzes the oxidative deamination of d-amino acids. DAO is present in a wide variety of organisms and has important roles. Here, we review the distribution and physiological substrates of mouse DAO. Mouse DAO is present in the kidney, brain, and spinal cord, like DAOs in other mammals. However, in contrast to other animals, it is not present in the mouse liver. Recently, DAO has been detected in the neutrophils, retina, and small intestine in mice. To determine the physiological substrates of mouse DAO, mutant mice lacking DAO activity are helpful. As DAO has wide substrate specificity and degrades various d-amino acids, many d-amino acids accumulate in the tissues and body fluids of the mutant mice. These amino acids are d-methionine, d-alanine, d-serine, d-leucine, d-proline, d-phenylalanine, d-tyrosine, and d-citrulline. Even in wild-type mice, administration of DAO inhibitors elevates D-serine levels in the plasma and brain. Among the above d-amino acids, the main physiological substrates of mouse DAO are d-alanine and d-serine. These two d-amino acids are most abundant in the tissues and body fluids of mice. d-Alanine derives from bacteria and produces bactericidal reactive oxygen species by the action of DAO. d-Serine is synthesized by serine racemase and is present especially in the central nervous system, where it serves as a neuromodulator. DAO is responsible for the metabolism of d-serine. Since DAO has been implicated in the etiology of neuropsychiatric diseases, mouse DAO has been used as a representative model. Recent reports, however, suggest that mouse DAO is different from human DAO with respect to important properties. PMID:29255714

Dietary Deficiency of Essential Amino Acids Rapidly Induces Cessation of the Rat Estrous Cycle

PubMed Central

Bannai, Makoto; Ichimaru, Toru; Nakano, Sayako; Murata, Takuya; Higuchi, Takashi; Takahashi, Michio

2011-01-01

Reproductive functions are regulated by the sophisticated coordination between the neuronal and endocrine systems and are sustained by a proper nutritional environment. Female reproductive function is vulnerable to effects from dietary restrictions, suggesting a transient adaptation that prioritizes individual survival over reproduction until a possible future opportunity for satiation. This adaptation could also partially explain the existence of amenorrhea in women with anorexia nervosa. Because amino acid nutritional conditions other than caloric restriction uniquely alters amino acid metabolism and affect the hormonal levels of organisms, we hypothesized that the supply of essential amino acids in the diet plays a pivotal role in the maintenance of the female reproductive system. To test this hypothesis, we examined ovulatory cyclicity in female rats under diets that were deficient in threonine, lysine, tryptophan, methionine or valine. Ovulatory cyclicity was monitored by daily cytological evaluations of vaginal smears. After continuous feeding of the deficient diet, a persistent diestrus or anovulatory state was induced most quickly by the valine-deficient diet and most slowly by the lysine-deficient diet. A decline in the systemic insulin-like growth factor 1 level was associated with a dietary amino acid deficiency. Furthermore, a paired group of rats that were fed an isocaloric diet with balanced amino acids maintained normal estrous cyclicity. These disturbances of the estrous cycle by amino acid deficiency were quickly reversed by the consumption of a normal diet. The continuous anovulatory state in this study is not attributable to a decrease in caloric intake but to an imbalance in the dietary amino acid composition. With a shortage of well-balanced amino acid sources, reproduction becomes risky for both the mother and the fetus. It could be viewed as an adaptation to the diet, diverting resources away from reproduction and reallocating them to survival until well-balanced amino acid sources are found. PMID:22132231

An allostatic mechanism for M2 pyruvate kinase as an amino-acid sensor.

PubMed

Yuan, Meng; McNae, Iain W; Chen, Yiyuan; Blackburn, Elizabeth A; Wear, Martin A; Michels, Paul A M; Fothergill-Gilmore, Linda A; Hupp, Ted; Walkinshaw, Malcolm D

2018-05-10

We have tested the effect of all 20 proteinogenic amino acids on the activity of the M2 isoenzyme of pyruvate kinase (M2PYK) and show that within physiologically relevant concentrations, phenylalanine, alanine, tryptophan, methionine, valine, and proline act as inhibitors while histidine and serine act as activators. Size exclusion chromatography has been used to show that all amino acids, whether activators or inhibitors, stabilise the tetrameric form of M2PYK. In the absence of amino-acid ligands an apparent tetramer-monomer dissociation K d is estimated to be ~0.9 µM with a slow dissociation rate (t 1/2 ~ 15 min). X-ray structures of M2PYK complexes with alanine, phenylalanine, and tryptophan show the M2PYK locked in an inactive T-state conformation, while activators lock the M2PYK tetramer in the active R-state conformation. Amino-acid binding in the allosteric pocket triggers rigid body rotations (11°) stabilising either T or R-states. The opposing inhibitory and activating effects of the non-essential amino acids serine and alanine suggest that M2PYK could act as a rapid-response nutrient sensor to rebalance cellular metabolism. This competition at a single allosteric site between activators and inhibitors provides a novel regulatory mechanism by which M2PYK activity is finely tuned by the relative (but not absolute) concentrations of activator and inhibitor amino acids. Such 'allostatic' regulation may be important in metabolic reprogramming and influencing cell fate. ©2018 The Author(s).

An allostatic mechanism for M2 pyruvate kinase as an amino-acid sensor

PubMed Central

McNae, Iain W.; Chen, Yiyuan; Blackburn, Elizabeth A.; Wear, Martin A.; Hupp, Ted

2018-01-01

We have tested the effect of all 20 proteinogenic amino acids on the activity of the M2 isoenzyme of pyruvate kinase (M2PYK) and show that, within physiologically relevant concentrations, phenylalanine, alanine, tryptophan, methionine, valine, and proline act as inhibitors, while histidine and serine act as activators. Size exclusion chromatography has been used to show that all amino acids, whether activators or inhibitors, stabilise the tetrameric form of M2PYK. In the absence of amino-acid ligands an apparent tetramer–monomer dissociation Kd is estimated to be ∼0.9 µM with a slow dissociation rate (t1/2 ∼ 15 min). X-ray structures of M2PYK complexes with alanine, phenylalanine, and tryptophan show the M2PYK locked in an inactive T-state conformation, while activators lock the M2PYK tetramer in the active R-state conformation. Amino-acid binding in the allosteric pocket triggers rigid body rotations (11°) stabilising either T or R states. The opposing inhibitory and activating effects of the non-essential amino acids serine and alanine suggest that M2PYK could act as a rapid-response nutrient sensor to rebalance cellular metabolism. This competition at a single allosteric site between activators and inhibitors provides a novel regulatory mechanism by which M2PYK activity is finely tuned by the relative (but not absolute) concentrations of activator and inhibitor amino acids. Such ‘allostatic’ regulation may be important in metabolic reprogramming and influencing cell fate. PMID:29748232

The glyoxysomal and plastid molecular chaperones (70-kDa heat shock protein) of watermelon cotyledons are encoded by a single gene

PubMed Central

Wimmer, Bernhard; Lottspeich, Friedrich; van der Klei, Ida; Veenhuis, Marten; Gietl, Christine

1997-01-01

The monoclonal a-70-kDa heat shock protein (hsp70) antibody recognizes in crude extracts from watermelon (Citrullus vulgaris) cotyledons two hsps with molecular masses of 70 and 72 kDa. Immunocytochemistry on watermelon cotyledon tissue and on isolated glyoxysomes identified hsp70s in the matrix of glyoxysomes and plastids. Affinity purification and partial amino acid determination revealed the 70-kDa protein to share high sequence identity with cytosolic hsp70s from a number of plant species, while the 72 kDa protein was very similar to plastid hsp70s from pea and cucumber. A full-length cDNA clone encoding the 72-kDa hsp70 was isolated and identified two start methionines in frame within the N-terminal presequence leading either to an N-terminal extension of 67 amino acids or to a shorter one of 47 amino acids. The longer presequence was necessary and sufficient to target a reporter protein into watermelon proplastids in vitro. The shorter extension starting from the second methionine within the long version harbored a consensus peroxisomal targeting signal (RT-X5-KL) that directed in vivo a reporter protein into peroxisomes of the yeast Hansenula polymorpha. Peroxisomal targeting was however prevented, when the 67-residue presequence was fused to the reporter protein, indicating that the peroxisomal targeting signal 2 information is hidden in this context. We propose that the 72-kDa hsp70 is encoded by a single gene, but targeted alternatively into two organelles by the modulated use of its presequence. PMID:9391076

Safety of methionine, a novel biopesticide, to adult and larval honey bees (Apis mellifera L.).

PubMed

Weeks, Emma N I; Schmehl, Daniel R; Baniszewski, Julie; Tomé, Hudson V V; Cuda, James P; Ellis, James D; Stevens, Bruce R

2018-03-01

Methionine is an essential/indispensible amino acid nutrient required by adult and larval honey bees (Apis mellifera L. [Hymenoptera: Apidae]). Bees are unable to rear broods on pollen deficient in methionine, and reportedly behaviorally avoid collecting pollen or nectar from florets deficient in methioinine. In contrast, it has been demonstrated that methionine is toxic to certain pest insects; thus it has been proposed as an effective biopesticide. As an ecofriendly integrated pest management agent, methionine boasts a novel mode of action differentiating it from conventional pesticides, while providing non-target safety. Pesticides that minimize collateral effects on bees are desirable, given the economic and ecological concerns about honey bee health. The aim of the present study was to assess the potential impact of the biopesticide methionine on non-target adult and larval honey bees. Acute contact adult toxicology bioassays, oral adult assessments and chronic larval toxicity assessments were performed as per U.S. Environmental Protection Agency (EPA) requirements. Our results demonstrated that methionine fits the U.S. EPA category of practically nontoxic (i.e. lethal dose to 50% mortality or LD 50 > 11µg/bee) to adult honey bees. The contact LD 50 was > 25µg/bee and the oral LD 50 was > 100µg/bee. Mortality was observed in larval bees that ingested DL-methionine (effective concentration to 50% mortality or EC 50 560µg/bee). Therefore, we conclude that methionine poses little threat to the health of the honey bee, due to unlikely exposure at concentrations shown to elicit toxic effects. Copyright © 2017 Elsevier Inc. All rights reserved.

Beta-and gamma-turns in proteins revisited: a new set of amino acid turn-type dependent positional preferences and potentials.

PubMed

Guruprasad, K; Rajkumar, S

2000-06-01

The number of beta-turns in a representative set of 426 protein three-dimensional crystal structures selected from the recent Protein Data Bank has nearly doubled and the number of gamma-turns in a representative set of 320 proteins has increased over seven times since the previous analysis. Beta-turns (7153) and gamma-turns (911) extracted from these proteins were used to derive a revised set of type-dependent amino acid positional preferences and potentials. Compared with previous results, the preference for proline, methionine and tryptophan has increased and the preference for glutamine, valine, glutamic acid and alanine has decreased for beta-turns. Certain new amino acid preferences were observed for both turn types and individual amino acids showed turn-type dependent positional preferences. The rationale for new amino acid preferences are discussed in the light of hydrogen bonds and other interactions involving the turns. Where main-chain hydrogen bonds of the type NH(i + 3) --> CO(i) were not observed for some beta-turns, other main-chain hydrogen bonds or solvent interactions were observed that possibly stabilize such beta-turns. A number of unexpected isolated beta-turns with proline at i + 2 position were also observed. The NH(i + 2) --> CO(i) hydrogen bond was observed for almost all gamma-turns. Nearly 20% classic gamma-turns and 43% inverse gamma-turns are isolated turns.

PLASMA PROTEIN AND HEMOGLOBIN PRODUCTION : DELETION OF INDIVIDUAL AMINO ACIDS FROM GROWTH MIXTURE OF TEN ESSENTIAL AMINO ACIDS. SIGNIFICANT CHANGES IN URINARY NITROGEN.

PubMed

Robscheit-Robbins, F S; Miller, L L; Whipple, G H

1947-02-28

Given healthy dogs fed abundant iron and protein-free or low protein diets with sustained anemia and hypoproteinemia, we can study the capacity of these animals to produce simultaneously new hemoglobin and plasma protein. Reserve stores of blood protein-building materials are measurably depleted and levels of 6 to 8 gm. per cent for hemoglobin and 4 to 5 gm. per cent for plasma protein can be maintained for weeks or months depending upon the intake of food proteins or amino acid mixtures. These dogs are very susceptible to infection and various poisons. Dogs tire of these diets and loss of appetite terminates many experiments. Under these conditions (double depletion) standard growth mixtures of essential amino acids are tested to show the response in blood protein output and urinary nitrogen balance. As a part of each tabulated experiment one of the essential amino acids is deleted from the complete growth mixture to compare such response with that of the whole mixture. Methionine, threonine, phenylalanine, and tryptophane when singly eliminated from the complete amino acid mixture do effect a sharp rise in urinary nitrogen. This loss of urinary nitrogen is corrected when the individual amino acid is replaced in the mixture. Histidine, lysine, and valine have a moderate influence upon urinary nitrogen balance toward nitrogen conservation. Leucine, isoleucine, and arginine have minimal or no effect upon urinary nitrogen balance when these individual amino acids are deleted from the complete growth mixture of amino acids during 3 to 4 week periods. Tryptophane and to a less extent phenylalanine and threonine when returned to the amino acid mixture are associated with a conspicuous preponderance of plasma protein output over the hemoglobin output (Table 4). Arginine, lysine, and histidine when returned to the amino acid mixture are associated with a large preponderance of hemoglobin output. Various amino acid mixtures under these conditions may give a positive urinary nitrogen balance and a liberal output of blood proteins but there is always weight loss, however we may choose to explain this loss. These experiments touch on the complex problems of parenteral nutrition, experimental and clinical.

Folic acid, neurodegenerative and neuropsychiatric disease.

PubMed

Kronenberg, Golo; Colla, Michael; Endres, Matthias

2009-04-01

Folic acid plays an important role in neuroplasticity and in the maintenance of neuronal integrity. Folate is a co-factor in one-carbon metabolism during which it promotes the regeneration of methionine from homocysteine, a highly reactive sulfur-containing amino acid. Methionine may then be converted to S-adenosylmethionine (SAM), the principal methyl donor in most biosynthetic methylation reactions. On the cellular level, folate deficiency and hyperhomocysteinemia exert multiple detrimental effects. These include induction of DNA damage, uracil misincorporation into DNA and altered patterns of DNA methylation. Low folate status and elevated homocysteine increase the generation of reactive oxygen species and contribute to excitotoxicity and mitochondrial dysfunction which may lead to apoptosis. Strong epidemiological and experimental evidence links derangements of one-carbon metabolism to vascular, neurodegenerative and neuropsychiatric disease, including most prominently cerebral ischemia, Alzheimer's dementia and depression. Although firm evidence from controlled clinical trials is largely lacking, B-vitamin supplementation and homocysteine reduction may have a role especially in the primary prevention of stroke and dementia as well as as an adjunct to antidepressant pharmacotherapy.

Influence of cadmium stress on root exudates of high cadmium accumulating rice line (Oryza sativa L.).

PubMed

Fu, Huijie; Yu, Haiying; Li, Tingxuan; Zhang, Xizhou

2018-04-15

A hydroponic experiment with two different cadmium (Cd) accumulating rice lines of Lu527-8 (the high Cd accumulating rice line) and Lu527-4 (the normal rice line) was carried out to explore the links among Cd stress, root exudates and Cd accumulation. The results showed that (1) Cd stress increased quantities of organic acids, but had no effect on composition in root exudates of the two rice lines. In Cd treatments, the contents of every detected organic acid in root exudates of Lu527-8 were 1.76-2.43 times higher than those of Lu527-4. Significant positive correlations between organic acids contents and Cd contents in plants were observed in both rice lines, except that malic acid was only highly relevant to Lu527-8, but not to Lu527-4. (2) Both composition and quantities of amino acids in root exudates changed a lot under Cd stress and this change differed in two rice lines. In control, four amino acids (glutamic acid, glycine, tyrosine and histidine) were detected in two rice lines. Under Cd stress, eight amino acids in Lu527-8 and seven amino acids in Lu527-4 could be detected, among which phenylalanine was only secreted by Lu527-8 and alanine, methionine and lysine were secreted by both rice lines. The contents of those four newly secreted amino acids from Lu527-8 increased significantly with the increase of Cd dose and each had a high-positive correlation with Cd contents, but the same change did not appear in Lu527-4. The difference between two rice lines in secretion of organic acids and amino acids may be related to their different Cd uptake properties. Copyright © 2017 Elsevier Inc. All rights reserved.

Chemical composition and nutritional evaluation of the seeds of Acacia tortilis (Forssk.) Hayne ssp. raddiana.

PubMed

Embaby, Hassan E; Rayan, Ahmed M

2016-06-01

Chemical composition and nutritional evaluation as well as physicochemical and functional properties of seed flour of Acacia tortilis (Forssk.) Hayne ssp. raddiana were studied. The results indicated that seeds contained 5.30% moisture, 3.99% ash, 9.19% fat, 14.31% fiber, 27.21% protein and 45.30% carbohydrates. Potassium was the predominant element followed by calcium and then phosphorous. Phytic acid, tannins and trypsin inhibitor as antinutrients were detected. The amino acid profile compared well with FAO/WHO recommended pattern except for cystine/methionine, isoleucine, tyrosine/phenylalanine, lysine and threonine. Also, the first limiting amino acid was lysine. Fatty acid composition showed that linoleic acid was the major fatty acid, followed by palmitic, stearic, oleic and arachidic acids. The seed oil showed absorbance in the ultraviolet ranges, thus it can be used as a broad spectrum UV protectant. For physicochemical and functional properties, acacia seeds flour had excellent water holding index, swelling index, foaming capacity and foam stability. Copyright © 2016 Elsevier Ltd. All rights reserved.

Comparison of the amino acid compositions and antigenic properties of spiralins purified from the plasma membranes of different spiroplasmas.

PubMed

Wróblewski, H; Robic, D; Thomas, D; Blanchard, A

1984-01-01

Spiralins were purified by agarose-suspension electrophoresis after extraction with detergents from the membranes of the following spiroplasmas: Spiroplasma citri C189, S. citri Maroc (R8A2), S. citri Scaph and the honey-bee spiroplasma B88. The four proteins (molecular mass congruent to 26,000 daltons, as determined by sodium dodecyl sulphate-pore gradient electrophoresis) showed very similar amino acid compositions characterized by the absence of methionine and tryptophan and a high polarity index (greater than 49%). When compared with the amino acid composition of S. citri membrane, the four spiralins had little or no histidine, a low content of glycine, leucine, tyrosine, phenylalanine and arginine, and a high content of threonine, alanine and valine. Comparison of the amino acid compositions according to the criteria described by Cornish-Bowden (Anal. Biochem., 1980, 105, 233-238) strongly suggests that all four spiralins are related. A crossed immunoelectrophoretical comparison, however, shows that though the three proteins purified from S. citri strains (serogroup I-1) are antigenically similar, they do not seem to share common epitopes with spiralin from the honey-bee spiroplasma B88 (serogroup I-2).

Appendix. Cloning and sequence of the gene encoding enzyme E-1 from the methionine salvage pathway of Klebsiella oxytoca.

PubMed

Balakrishnan, R; Frohlich, M; Rahaim, P T; Backman, K; Yocum, R R

1993-11-25

The methionine salvage pathway converts the methylthioribose moiety of 5'-(methylthio)-adenosine to methionine via a series of biochemical steps. One enzyme active in this pathway, a bifunctional enolase-phosphatase called E-1 that promotes oxidative cleavage of the synthetic substrate 2,3-diketo-1-phosphohexane to 2-keto-pentanoate, has been purified from Klebsiella pneumoniae and is characterized in the preceding paper (Myers, R., Wray, J., Fish, S., and Abeles, R. H. (1993) J. Biol. Chem. 268, 24785-24791). We synthesized degenerate oligonucleotides corresponding to portions of the amino terminus of E-1. These oligonucleotides were used as polymerase chain reaction primers on whole genomic DNA from Klebsiella oxytoca. This resulted in an 82-base pair DNA fragment that was used as a hybridization probe to obtain a clone of the E-1 gene from a K. oxytoca gene library. The DNA sequence of the E-1 coding region was determined, and the amino acid sequence of E-1 was deduced. E-1 appears to represent a novel class of enzymes since no homology to known enzymes was found. Cloning the gene from K. oxytoca on a multicopy plasmid leads to overproduction of E-1 enzyme that has properties indistinguishable from those of the enzyme from K. pneumoniae.

Chemical and physical investigations on the charge transfer interaction of organic donors with iodine and its application as non-traditional organic conductors

NASA Astrophysics Data System (ADS)

Refat, Moamen S.; Sharshar, T.; Adam, Abdel Majid A.; Elsabawy, Khaled M.; Hemeda, O. M.

2014-09-01

The iso-leucine-iodide and methionine-iodide charge-transfer complexes were prepared and characterized using different spectroscopic techniques. The iodide charge-transfer complexes were synthesized by grinding KI-I2-amino acid with 1:1:1 M ratio in presence of few drops of methanol solvent. The structures of both solid amino acid iodide charge-transfer complexes are discussed with the help of the obtained results of the infrared and Raman laser spectra, Uv-vis. electronic spectra and thermal analyses. The electrical properties (AC resistivity and dielectric constant) of both complexes were investigated. The positron annihilation Doppler broadening (PADB) spectroscopies were also used to probe the structural changes of both complexes. The PADB line-shape parameters (S and W) were found to be dependent on the structure, electronic configuration of the charge transfer complex. The PADB technique is a powerful tool to probe the structural features of the KI-I2-amino acid complexes.

Biosynthesis of Ethylene from Methionine in Aminoethoxyvinylglycine-Resistant Avocado Tissue

PubMed Central

Baker, James E.; Anderson, James D.; Adams, Douglas O.; Apelbaum, Akiva; Lieberman, Morris

1982-01-01

This study was conducted to determine if aminoethoxyvinylglycine (AVG) insensitivity in avocado (Persea americana Mill., Lula, Haas, and Bacon) tissue was due to an alternate pathway of ethylene biosynthesis from methionine. AVG, at 0.1 millimolar, had little or no inhibitory effect on either total ethylene production or [14C] ethylene production from [14C]methionine in avocado tissue at various stages of ripening. However, aminoxyacetic acid (AOA), which inhibits 1-aminocyclopropane-1-carboxylic acid (ACC) synthase (the AVG-sensitive enzyme of ethylene biosynthesis), inhibited ethylene production in avocado tissue. Total ethylene production was stimulated, and [14C]ethylene production from [14C]methionine was lowered by treating avocado tissue with 1 millimolar ACC. An inhibitor of methionine adenosyltransferase (EC 2.5.1.6), l-2-amino-4-hexynoic acid (AHA), at 1.5 millimolar, effectively inhibited [14C]ethylene production from [14C]methionine in avocado tissue but had no effect on total ethylene production during a 2-hour incubation. Rates of [14C]AVG uptake by avocado and apple (Malus domestica Borkh., Golden Delicious) tissues were similar, and [14C]AVG was the only radioactive compound in alcohol-soluble fractions of the tissues. Hence, AVG-insensitivity in avocado tissue does not appear to be due to lack of uptake or to metabolism of AVG by avocado tissue. ACC synthase activity in extracts of avocado tissue was strongly inhibited (about 60%) by 10 micromolar AVG. Insensitivity of ethylene production in avocado tissue to AVG may be due to inaccessibility of ACC synthase to AVG. AVG-resistance in the avocado system is, therefore, different from that of early climacteric apple tissue, in which AVG-insensitivity of total ethylene production appears to be due to a high level of endogenous ACC relative to its rate of conversion to ethylene. However, the sensitivity of the avocado system to AOA and AHA, dilution of labeled ethylene production by ACC, and stimulation of total ethylene production by ACC provide evidence for the methionine → SAM → ACC → ethylene pathway in avocado and do not suggest the operation of an alternate pathway. PMID:16662192

TOLERANCE TO AMINO ACID MIXTURES AND CASEIN DIGESTS GIVEN INTRAVENOUSLY

PubMed Central

Madden, S. C.; Woods, R. R.; Shull, F. W.; Remington, J. H.; Whipple, G. H.

1945-01-01

Several synthetic mixtures of natural and racemic crystalline amino acids suitable for the daily nitrogen requirement are tested in dogs for their tolerance upon intravenous injection. Certain mixtures of the ten essential amino acids plus non-essential amino acids exclusive of glutamic acid are accepted without any obvious sign of disturbance even at rates above 10 mg. nitrogen per kilo per minute for quantities greater than 300 mg. per kilo. One such mixture consists in parts per 100 of dl-threonine 7, dl-valine 15, l(-)-leucine 10.9, dl-isoleucine 9.9, l(+)-lysine· HCl·H2O 10.9, dl-tryptophane 3, dl-phenylalanine 9.9, dl-methionine 6, l(+)-histidine·HCl·H2O 5, l(+)-arginine-HCl 5, glycine 9.9, dl-α-alanine 4, dl-serine 2, l(-)-cystine 0.5, and l(-)-tyrosine 1. In addition other well tolerated mixtures included the prolines. When glutamic acid, natural or racemic, is included in similar mixtures vomiting reactions frequently occur at nitrogen rates above 4 mg. per kilo per minute. Vomiting almost always occurs on the first daily injection containing glutamic acid and usually on any subsequent injection containing more than 100 mg. glutamic acid per kilo unless given very slowly. Upon the addition of glycine certain mixtures of the ten essential amino acids show an improved tolerance. Two casein digests tested usually produced vomiting at injection rates above 2 mg. nitrogen per kilo per minute, probably because of their glutamic acid content. No serious reaction has ever occurrred to any mixture of amino acids or casein digest tested. Elimination of minor reactions such as vomiting appears possible and desirable for greater usefulness of these solutions in parenteral feeding. PMID:19871468

Peptides with morphine-like action in the brain.

PubMed

Kosterlitz, H W; Hughes, J

1977-03-01

The reasons which led to the search in the brain for substances with morphine-like actions actions are discussed. Two pentapeptides, methionineenkephalin and leucine-enkephalin, were isolated. The amino acid sequence of methionine-enkephalin occurs also in the pituitary prohormone beta-lipotropin, of which longer fragments (endorphins) of up to 31 amino acids exhibit strong morphine-like action. The physiological significance of these short and long opioid peptides is discussed, particularly with regard to their possible roles as neurotransmitter or neuromodulator. With regard to the mechanisms involved in the development of tolerance to and dependence on opiates, the importance of interaction between the endogenous opioid peptides and the exogenous opiate alkaloids is stressed. The possible therapeutic implications are discussed briefly.

Transcripts of sulphur metabolic genes are co-ordinately regulated in developing seeds of common bean lacking phaseolin and major lectins

PubMed Central

Marsolais, Frédéric

2012-01-01

The lack of phaseolin and phytohaemagglutinin in common bean (dry bean, Phaseolus vulgaris) is associated with an increase in total cysteine and methionine concentrations by 70% and 10%, respectively, mainly at the expense of an abundant non-protein amino acid, S-methyl-cysteine. Transcripts were profiled between two genetically related lines differing for this trait at four stages of seed development using a high density microarray designed for common bean. Transcripts of multiple sulphur-rich proteins were elevated, several previously identified by proteomics, including legumin, basic 7S globulin, albumin-2, defensin, albumin-1, the Bowman–Birk type proteinase inhibitor, the double-headed trypsin inhibitor, and the Kunitz trypsin inhibitor. A co-ordinated regulation of transcripts coding for sulphate transporters, sulphate assimilatory enzymes, serine acetyltransferases, cystathionine β-lyase, homocysteine S-methyltransferase and methionine gamma-lyase was associated with changes in cysteine and methionine concentrations. Differential gene expression of sulphur-rich proteins preceded that of sulphur metabolic enzymes, suggesting a regulation by demand from the protein sink. Up-regulation of SERAT1;1 and -1;2 expression revealed an activation of cytosolic O-acetylserine biosynthesis. Down-regulation of SERAT2;1 suggested that cysteine and S-methyl-cysteine biosynthesis may be spatially separated in different subcellular compartments. Analysis of free amino acid profiles indicated that enhanced cysteine biosynthesis was correlated with a depletion of O-acetylserine. These results contribute to our understanding of the regulation of sulphur metabolism in developing seed in response to a change in the composition of endogenous proteins. PMID:23066144

Transcripts of sulphur metabolic genes are co-ordinately regulated in developing seeds of common bean lacking phaseolin and major lectins.

PubMed

Liao, Dengqun; Pajak, Agnieszka; Karcz, Steven R; Chapman, B Patrick; Sharpe, Andrew G; Austin, Ryan S; Datla, Raju; Dhaubhadel, Sangeeta; Marsolais, Frédéric

2012-10-01

The lack of phaseolin and phytohaemagglutinin in common bean (dry bean, Phaseolus vulgaris) is associated with an increase in total cysteine and methionine concentrations by 70% and 10%, respectively, mainly at the expense of an abundant non-protein amino acid, S-methyl-cysteine. Transcripts were profiled between two genetically related lines differing for this trait at four stages of seed development using a high density microarray designed for common bean. Transcripts of multiple sulphur-rich proteins were elevated, several previously identified by proteomics, including legumin, basic 7S globulin, albumin-2, defensin, albumin-1, the Bowman-Birk type proteinase inhibitor, the double-headed trypsin inhibitor, and the Kunitz trypsin inhibitor. A co-ordinated regulation of transcripts coding for sulphate transporters, sulphate assimilatory enzymes, serine acetyltransferases, cystathionine β-lyase, homocysteine S-methyltransferase and methionine gamma-lyase was associated with changes in cysteine and methionine concentrations. Differential gene expression of sulphur-rich proteins preceded that of sulphur metabolic enzymes, suggesting a regulation by demand from the protein sink. Up-regulation of SERAT1;1 and -1;2 expression revealed an activation of cytosolic O-acetylserine biosynthesis. Down-regulation of SERAT2;1 suggested that cysteine and S-methyl-cysteine biosynthesis may be spatially separated in different subcellular compartments. Analysis of free amino acid profiles indicated that enhanced cysteine biosynthesis was correlated with a depletion of O-acetylserine. These results contribute to our understanding of the regulation of sulphur metabolism in developing seed in response to a change in the composition of endogenous proteins.

Ferrate oxidation of Escherichia coli DNA polymerase-I. Identification of a methionine residue that is essential for DNA binding.

PubMed

Basu, A; Williams, K R; Modak, M J

1987-07-15

Treatment of Escherichia coli DNA polymerase-I with potassium ferrate (K2FeO4), a site-specific oxidizing agent for the phosphate group-binding sites of proteins, results in the irreversible inactivation of enzyme activity as judged by the loss of polymerization as well as 3'-5' exonuclease activity. A significant protection from ferrate-mediated inactivation is observed in the presence of DNA but not by substrate deoxynucleoside triphosphates. Furthermore, ferrate-treated enzyme also exhibits loss of template-primer binding activity, whereas its ability to bind substrate triphosphates is unaffected. In addition, comparative high pressure liquid chromatography tryptic peptide maps obtained before and after ferrate oxidation demonstrated that only five peptides of the more than 60 peptide peaks present in the tryptic digest underwent a major change in either peak position or intensity as a result of ferrate treatment. Amino acid analyses and/or sequencing identified four of these affected peaks as corresponding to peptides that span residues 324-340, 437-455, 456-464, and 512-518, respectively. However, only the last peptide, which has the sequence: Met-Trp-Pro-Asp-Leu-Gln-Lys, was significantly protected in the presence of DNA. This latter peptide was also the only peptide whose degree of oxidation correlated directly with the extent of inactivation of the enzyme. Amino acid analysis indicated that methionine 512 is the target site in this peptide for ferrate oxidation. Methionine 512, therefore, appears to be essential for the DNA-binding function of DNA polymerase-I from E. coli.

Oxidation of methionine 216 in sheep and elk prion protein is highly dependent upon the amino acid at position 218 but is not important for prion propagation

USDA-ARS?s Scientific Manuscript database

We developed a sensitive mass spectrometry-based method of quantitating the prions present in elk and sheep. Calibration curves relating the area ratios of the selected analyte peptides and their homologous stable isotope labeled internal standards were prepared. This method was compared to the ELIS...

A review of flavor, aroma and color enhancement in gluten free and conventional pastries, waffles and dairy desserts with mesquite pod mesocarp flour (abstract)

USDA-ARS?s Scientific Manuscript database

Mesquite is a nitrogen fixing tree whose pods were a major food for indigenous desert peoples. The main mesquite flour of commerce is milled from the pod mesocarp (without seeds) and contains 45% sucrose, 25% dietary fiber, 8 % protein, and 2 % fat. The limiting amino acids are methionine and cystei...

Design of experiments for amino acid extraction from tobacco leaves and their subsequent determination by capillary zone electrophoresis.

PubMed

Hodek, Ondřej; Křížek, Tomáš; Coufal, Pavel; Ryšlavá, Helena

2017-03-01

In this study, we optimized a method for the determination of free amino acids in Nicotiana tabacum leaves. Capillary electrophoresis with contactless conductivity detector was used for the separation of 20 proteinogenic amino acids in acidic background electrolyte. Subsequently, the conditions of extraction with HCl were optimized for the highest extraction yield of the amino acids because sample treatment of plant materials brings some specific challenges. Central composite face-centered design with fractional factorial design was used in order to evaluate the significance of selected factors (HCl volume, HCl concentration, sonication, shaking) on the extraction process. In addition, the composite design helped us to find the optimal values for each factor using the response surface method. The limits of detection and limits of quantification for the 20 proteinogenic amino acids were found to be in the order of 10 -5 and 10 -4  mol l -1 , respectively. Addition of acetonitrile to the sample was tested as a method commonly used to decrease limits of detection. Ambiguous results of this experiment pointed out some features of plant extract samples, which often required specific approaches. Suitability of the method for metabolomic studies was tested by analysis of a real sample, in which all amino acids, except for L-methionine and L-cysteine, were successfully detected. The optimized extraction process together with the capillary electrophoresis method can be used for the determination of proteinogenic amino acids in plant materials. The resulting inexpensive, simple, and robust method is well suited for various metabolomic studies in plants. As such, the method represents a valuable tool for research and practical application in the fields of biology, biochemistry, and agriculture.

Quantification of methionine and selenomethionine in biological samples using multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS).

PubMed

Vu, Dai Long; Ranglová, Karolína; Hájek, Jan; Hrouzek, Pavel

2018-05-01

Quantification of selenated amino-acids currently relies on methods employing inductively coupled plasma mass spectrometry (ICP-MS). Although very accurate, these methods do not allow the simultaneous determination of standard amino-acids, hampering the comparison of the content of selenated versus non-selenated species such as methionine (Met) and selenomethionine (SeMet). This paper reports two approaches for the simultaneous quantification of Met and SeMet. In the first approach, standard enzymatic hydrolysis employing Protease XIV was applied for the preparation of samples. The second approach utilized methanesulfonic acid (MA) for the hydrolysis of samples, either in a reflux system or in a microwave oven, followed by derivatization with diethyl ethoxymethylenemalonate. The prepared samples were then analyzed by multiple reaction monitoring high performance liquid chromatography tandem mass spectrometry (MRM-HPLC-MS/MS). Both approaches provided platforms for the accurate determination of selenium/sulfur substitution rate in Met. Moreover the second approach also provided accurate simultaneous quantification of Met and SeMet with a low limit of detection, low limit of quantification and wide linearity range, comparable to the commonly used gas chromatography mass spectrometry (GC-MS) method or ICP-MS. The novel method was validated using certified reference material in conjunction with the GC-MS reference method. Copyright © 2018. Published by Elsevier B.V.

Methylation of nuclear proteins by dimethylnitrosamine and by methionine in the rat in vivo

PubMed Central

Turberville, C.; Craddock, V. M.

1971-01-01

1. The incorporation of methyl groups into histones from dimethylnitrosamine and from methionine was studied by injection of the labelled compounds, isolation of rat liver and kidney histones, and analysis of hydrolysates by column chromatography. 2. Labelled methionine gave rise to labelled ∈-N-methyl-lysine, di-∈-N-methyl-lysine and an amino acid presumed to be ω-N-methyl-arginine. 3. Administration of labelled dimethylnitrosamine gave rise to labelled S-methylcysteine, 1-methylhistidine, 3-methylhistidine and ∈-N-methyl-lysine derived from the alkylating metabolite of dimethylnitrosamine. In addition, labelled formaldehyde released by metabolism of dimethylnitrosamine leads to the formation of labelled S-adenosylmethionine, and hence to labelling of ∈-N-methyl-lysine, di-∈-N-methyl-lysine and ω-N-methylarginine by enzymic methylation. 4. The formation of ∈-N-methyl-lysine by alkylation of liver histones was confirmed by using doubly labelled dimethylnitrosamine to discriminate between direct chemical alkylation and enzymic methylation via S-adenosylmethionine. These experiments also suggested the possibility that methionine residues in the histones were alkylated to give methylmethionine sulphonium residues. 5. The extent of alkylation of liver histones was maximal at about 5h after dosing and declined between 5 and 24h. The methylated amino acids resulting from direct chemical alkylation were preferentially lost: this is ascribed to necrosis of the more highly alkylated cells. 6. Liver histones were about four times as alkylated as kidney histones; the extent of alkylation of liver histones was similar to that of liver total nuclear proteins. 7. Methyl methanesulphonate (120mg/kg) alkylated liver histones to a greater extent than did dimethylnitrosamine. Diethylnitrosamine also alkylated liver histones. 8. The results are discussed with regard to the possible effects of alkylation on histone function, and the possible role of histone alkylation in carcinogenesis by the three compounds. PMID:5131729

Emerging Perspectives on Essential Amino Acid Metabolism in Obesity and the Insulin-Resistant State12

PubMed Central

Adams, Sean H.

2011-01-01

Dysregulation of insulin action is most often considered in the context of impaired glucose homeostasis, with the defining feature of diabetes mellitus being elevated blood glucose concentration. Complications arising from the hyperglycemia accompanying frank diabetes are well known and epidemiological studies point to higher risk toward development of metabolic disease in persons with impaired glucose tolerance. Although the central role of proper blood sugar control in maintaining metabolic health is well established, recent developments have begun to shed light on associations between compromised insulin action [obesity, prediabetes, and type 2 diabetes mellitus (T2DM)] and altered intermediary metabolism of fats and amino acids. For amino acids, changes in blood concentrations of select essential amino acids and their derivatives, in particular BCAA, sulfur amino acids, tyrosine, and phenylalanine, are apparent with obesity and insulin resistance, often before the onset of clinically diagnosed T2DM. This review provides an overview of these changes and places recent observations from metabolomics research into the context of historical reports in the areas of biochemistry and nutritional biology. Based on this synthesis, a model is proposed that links the FFA-rich environment of obesity/insulin resistance and T2DM with diminution of BCAA catabolic enzyme activity, changes in methionine oxidation and cysteine/cystine generation, and tissue redox balance (NADH/NAD+). PMID:22332087

Separation and partial characterization of guinea-pig caseins.

PubMed Central

Craig, R K; McIlreavy, D; Hall, R L

1978-01-01

1. Guinea-pig caseins A, B and C were purified free of each other by a combination of ion-exchange chromatography and gel filtration. 2. Determination of the amino acid composition showed all three caseins to contain a high proportion of proline and glutamic acid, but no cysteine. This apart, the amino acid composition of the three caseins was markedly different, though calculated divergence values suggest that some homology may exist between caseins A and B. Molecular-weight estimates based on amino acid composition were in good agreement with those based on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis. 3. N-Terminal analysis showed lysine, methionine and lysine to be the N-terminal residues of caseins A, B and C respectively. 4. Two-dimensional separation of tryptic digests revealed a distinctive pattern for each casein. 5. All caseins were shown to be phosphoproteins. The casein C preparation also contained significant amounts of sialic acid, neutral and amino sugars. 6. The results suggest that each casein represents a separate gene product, and that the low-molecular-weight proteins are not the result of a post-translational cleavage of the largest. All were distinctly different from the whey protein alpha-lactalbumin. Images Fig. 3. Fig. 4. Fig. 5. Fig. 6. PMID:697741

Mutational studies in X-linked Charcot-Marie-Tooth disease (CMTX)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Cherryson, A.K.; Yeung, L.; Kennerson, M.L.

1994-09-01

Charcot-Marie-Tooth disease, also known as hereditary motor and sensory neuropathy (HMSN), is a heterogeneous group of slowly progressive disorders of the peripheral nerve. X-linked CMT (CMTX) is characterized by slow motor nerve conduction velocities in affected males and the presence of mildly affected or normal carrier females with intermediate or normal nerve conduction velocities. CMTX, which has an incidence of 3.1 per 100,000 and accounts for approximately 10% of CMT cases, has been mapped to Xq13. One of the genes lying in this region, connexin 32, has been found to contain alterations in individuals affected with X-linked CMT. We havemore » identified our X-linked families from dominant type 1 CMT families using the clinical criteria given above. These families were screened for point mutations in connexin 32. We have identified three missense mutations, a G{r_arrow}A transition at amino acid 35 (valine to methionine), a C{r_arrow}G transition at amino acid 158 (proline to alanine) and a T{r_arrow}A transition at amino acid 182 (serine to threonine). Another family showed a 18 bp deletion, which removed the amino acid 111 to 116 inclusive (histidine, glycine, aspartic acid, proline, leucine, histidine).« less

A Methionine-Induced Animal Model of Schizophrenia: Face and Predictive Validity.

PubMed

Wang, Lien; Alachkar, Amal; Sanathara, Nayna; Belluzzi, James D; Wang, Zhiwei; Civelli, Olivier

2015-05-19

Modulating the methylation process induces broad biochemical changes, some of which may be involved in schizophrenia. Methylation is in particular central to epigenesis, which is also recognized as a factor in the etiology of schizophrenia. Because methionine administration to patients with schizophrenia has been reported to exacerbate their psychotic symptoms and because mice treated with methionine exhibited social deficits and prepulse inhibition impairment, we investigated whether methionine administration could lead to behavioral changes that reflect schizophrenic symptoms in mice. l-Methionine was administered to mice twice a day for 7 days. We found that this treatment induces behavioral responses that reflect the 3 types of schizophrenia-like symptoms (positive, negative, or cognitive deficits) as monitored in a battery of behavioral assays (locomotion, stereotypy, social interaction, forced swimming, prepulse inhibition, novel object recognition, and inhibitory avoidance). Moreover, these responses were differentially reversed by typical haloperidol and atypical clozapine antipsychotics in ways that parallel their effects in schizophrenics. We thus propose the l-methionine treatment as an animal model recapitulating several symptoms of schizophrenia. We have established the face and predictive validity for this model. Our model relies on an essential natural amino acid and on an intervention that is relatively simple and time effective and may offer an additional tool for assessing novel antipsychotics. © The Author 2015. Published by Oxford University Press on behalf of CINP.

Functional mapping and implications of substrate specificity of the yeast high-affinity leucine permease Bap2.

PubMed

Usami, Yuki; Uemura, Satsohi; Mochizuki, Takahiro; Morita, Asami; Shishido, Fumi; Inokuchi, Jin-ichi; Abe, Fumiyoshi

2014-07-01

Leucine is a major amino acid in nutrients and proteins and is also an important precursor of higher alcohols during brewing. In Saccharomyces cerevisiae, leucine uptake is mediated by multiple amino acid permeases, including the high-affinity leucine permease Bap2. Although BAP2 transcription has been extensively analyzed, the mechanisms by which a substrate is recognized and moves through the permease remain unknown. Recently, we determined 15 amino acid residues required for Tat2-mediated tryptophan import. Here we introduced homologous mutations into Bap2 amino acid residues and showed that 7 residues played a role in leucine import. Residues I109/G110/T111 and E305 were located within the putative α-helix break in TMD1 and TMD6, respectively, according to the structurally homologous Escherichia coli arginine/agmatine antiporter AdiC. Upon leucine binding, these α-helix breaks were assumed to mediate a conformational transition in Bap2 from an outward-open to a substrate-binding occluded state. Residues Y336 (TMD7) and Y181 (TMD3) were located near I109 and E305, respectively. Bap2-mediated leucine import was inhibited by some amino acids according to the following order of severity: phenylalanine, leucine>isoleucine>methionine, tyrosine>valine>tryptophan; histidine and asparagine had no effect. Moreover, this order of severity clearly coincided with the logP values (octanol-water partition coefficients) of all amino acids except tryptophan. This result suggests that the substrate partition efficiency to the buried Bap2 binding pocket is the primary determinant of substrate specificity rather than structural amino acid side chain recognition. Copyright © 2014 Elsevier B.V. All rights reserved.

Study on bioactive compounds of in vitro cultured Calculus Suis and natural Calculus Bovis.

PubMed

Wan, Tien-Chun; Cheng, Fu-Yuan; Liu, Yu-Tse; Lin, Liang-Chuan; Sakata, Ryoichi

2009-12-01

The purpose of the study was to investigate bioactive compounds of in vitro cultured Calculus Suis and natural Calculus Bovis obtained as valuable by-products from animals used for meat production. The results showed that the components of natural Calculus Bovis were rich in bilirubin and biliverdin and had higher content of essential amino acids. The major amino acids of in vitro cultured Calculus Suis were identified as glycine, alanine, glutamic acid and aspartic acid, and those for natural Calculus Bovis were found to be glutamic acid, aspartic acid, proline, and arginine. The methionine and cysteine contents of precursors for glutathione in natural Calculus Bovis were significantly higher than those of in vitro cultured Calculus Suis. The mineral contents of zinc, iron and manganese of natural Calculus Bovis were significantly higher than those of in vitro cultured Calculus Suis. The major bile acids in both products were cholic acid and dehydrocholic acid, respectively. The chenodeoxycholic and ursodeoxycholic acid content of in vitro cultured Calculus Suis was significantly higher than that of natural Calculus Bovis.

l-Methionine anti-biofilm activity against Pseudomonas aeruginosa is enhanced by the cystic fibrosis transmembrane conductance regulator potentiator, ivacaftor.

PubMed

Cho, Do-Yeon; Lim, Dong-Jin; Mackey, Calvin; Weeks, Christopher G; Peña Garcia, Jaime A; Skinner, Daniel; Grayson, Jessica W; Hill, Harrison S; Alexander, David K; Zhang, Shaoyan; Woodworth, Bradford A

2018-05-01

Biofilms may contribute to refractory chronic rhinosinusitis (CRS), as they lead to antibiotic resistance and failure of effective clinical treatment. l-Methionine is an amino acid with reported biofilm-inhibiting properties. Ivacaftor is a cystic fibrosis transmembrane conductance regulator (CFTR) potentiator with mild antimicrobial activity via inhibition of bacterial DNA gyrase and topoisomerase IV. The objective of this study was to evaluate whether co-treatment with ivacaftor and l-methionine can reduce the formation of Pseudomonas aeruginosa biofilms. P aeruginosa (PAO-1 strain) biofilms were studied in the presence of l-methionine and/or ivacaftor. For static biofilm assays, PAO-1 was cultured in a 48-well plate for 72 hours with stepwise combinations of these agents. Relative biofilm inhibitions were measured according to optical density of crystal violet stain at 590 nm. Live/dead assays (BacTiter-Glo™ assay, Promega) were imaged with laser scanning confocal microscopy. An agar diffusion test was used to confirm antibacterial effects of the drugs. l-Methionine (0.5 μM) significantly reduced PAO-1 biofilm mass (32.4 ± 18.0%; n = 4; p < 0.001) compared with controls. Low doses of ivacaftor alone (4, 8, and 12 μg/mL) had no effect on biofilm formation. When combined with ivacaftor (4 μg/mL), a synergistic anti-biofilm effect was noted at 0.05 μM and 0.5 μM of l-methionine (two-way analysis of variane, p = 0.0415) compared with corresponding concentrations of l-methionine alone. Ivacaftor enhanced the anti-biofilm activity of l-methionine against the PAO-1 strain of P aeruginosa. Further studies evaluating the efficacy of ivacaftor/l-methionine combinations for P aeruginosa sinusitis are planned. © 2018 ARS-AAOA, LLC.

METABOLIC RESPONSES TO DIETARY LEUCINE RESTRICTION INVOLVE REMODELING OF ADIPOSE TISSUE AND ENHANCED HEPATIC INSULIN SIGNALING

PubMed Central

Wanders, Desiree; Stone, Kirsten P.; Dille, Kelly; Simon, Jacob; Pierse, Alicia; Gettys, Thomas W.

2015-01-01

Dietary leucine was incrementally restricted to test whether limiting this essential amino acid (EAA) would fully reproduce the beneficial responses produced by dietary methionine restriction. Restricting leucine by 85% increased energy intake and expenditure within five to seven days of its introduction and reduced overall accumulation of adipose tissue. Leucine restriction (LR) also improved glucose tolerance, increased hepatic release of FGF21 into the blood stream, and enhanced insulin-dependent activation of Akt in liver. However, LR had no effect on hepatic lipid levels and failed to lower lipogenic gene expression in the liver. LR did affect remodeling of white and brown adipose tissue, increasing expression of both thermogenic and lipogenic genes. These findings illustrate that dietary LR reproduces many but not all of the physiological responses of methionine restriction. The primary differences occur in the liver, where methionine and leucine restriction cause opposite effects on tissue lipid levels and expression of lipogenic genes. Together these findings suggest that the sensing systems which detect and respond to dietary restriction of EAAs act through mechanisms that both leucine and methionine are able to engage, and in the case of hepatic lipid metabolism, may be unique to specific EAAs such as methionine. PMID:26643647

Homocysteine: overview of biochemistry, molecular biology, and role in disease processes.

PubMed

Fowler, Brian

2005-05-01

Homocysteine is derived from the essential amino acid methionine and plays a vital role in cellular homeostasis in man. Homocysteine levels depend on its synthesis, involving methionine adenosyltransferase, S-adenosylmethionine-dependent methyltransferases such as glycine N-methyltransferase, and S-adenosylhomocysteine hydrolase; its remethylation to methionine by methionine synthase, which requires methionine synthase reductase, vitamin B (12), and 5-methyltetrahydrofolate produced by methylenetetrahydrofolate reductase or betaine methyltransferase; and its degradation by transsulfuration involving cystathionine beta-synthase. The control of homocysteine metabolism involves changes of tissue content or inherent kinetic properties of the enzymes. In particular, S-adenosylmethionine acts as a switch between remethylation and transsulfuration through its allosteric inhibition of methylenetetrahydrofolate reductase and activation of cystathionine beta-synthase. Mutant alleles of genes for these enzymes can lead to severe loss of function and varying severity of disease. Several defects lead to severe hyperhomocysteinemia, the most common form being cystathionine beta-synthase deficiency, with more than a hundred reported mutations. Less severe elevations of plasma homocysteine are caused by folate and vitamin B (12) deficiency, and renal disease and moderate hyperhomocysteinemia are associated with several common disease states such as cardiovascular disease. Homocysteine toxicity is likely direct or caused by disturbed levels of associated metabolites; for example, methylation reactions through elevated S-adenosylhomocysteine.

Determination of branched chain amino acids, methionine, phenylalanine, tyrosine and alpha-keto acids in plasma and dried blood samples using HPLC with fluorescence detection.

PubMed

Kand'ár, Roman; Záková, Pavla; Jirosová, Jana; Sladká, Michaela

2009-01-01

The determination of branched chain amino acids [BCAA; valine (Val), leucine (Leu), isoleucine (Ile)], alpha-keto acids derived from BCAA [BCKA; alpha-ketoisovaleric acid (KIV), alpha-ketoisocaproic acid (KIC), alpha-ketomethylvaleric acid (KMV)], methionine (Met), phenylalanine (Phe) and tyrosine (Tyr) is currently the most reliable approach for the diagnosis of maple syrup urine disease (MSUD), hypermethioninemia, phenylketonuria (PKU) and tyrosinemia. The aim of this study was to develop rapid and simple HPLC methods for measurement of BCAA, Met, Phe, Tyr and BCKA in plasma and dried blood samples. Samples of peripheral venous blood with EDTA as anticoagulant were obtained from a group of healthy blood donors (n=70, 35 females, 27-41 years of age and 35 males, 28-43 years of age). Blood-spot samples from a group of newborns (n=80, 40 girls and 40 boys 3-5 days of age) were collected onto #903 Specimen Collection Paper and allowed to dry for at least 24 h before analysis. Prior to separation, the amino acids (AA) were derivatized with o-phthaldialdehyde (OPA) and BCKA with o-phenylenediamine (OPD). Reverse phase column chromatography (LiChroCart 125-4 Purospher RP-18e, 5 microm) was used for separation and fluorescence detection used to monitoring of effluent. For AA analysis, 25 mmol/L sodium hydrogenphosphate-methanol (90:10, v/v), pH 6.5+/-0.1 was used as mobile phase A and 100% methanol was used as mobile phase B. Measurement of BCKA used a mixture of methanol and deionized water (55:45, v/v) as mobile phase A and mobile phase B consisted of 100% methanol. Analytical performance of these methods was satisfactory for the determination of all AA and BCKA. The intra-assay and inter-assay coefficients of variation were below 10% and recovery ranged from 90%-110%. We have developed simple, rapid and selective HPLC methods with fluorescence detection for the determination of BCAA, Met, Phe, Tyr and BCKA in plasma and dried blood samples.

Study of morphology, chemical, and amino acid composition of red deer meat.

PubMed

Okuskhanova, Eleonora; Assenova, Bahytkul; Rebezov, Maksim; Amirkhanov, Kumarbek; Yessimbekov, Zhanibek; Smolnikova, Farida; Nurgazezova, Almagul; Nurymkhan, Gulnur; Stuart, Marilyne

2017-06-01

The aim of this study was to evaluate red deer (maral) meat quality based on chemical composition, pH, water-binding capacity (WBC), and amino acid content. Maral meat surface morphology measurements were obtained by scanning electron microscopy. Active acidity (pH) was determined by potentiometry. Samples were analyzed for WBC by exudation of moisture to a filter paper by the application of pressure. Chemical composition (moisture, protein, fat, and ash fractions) was obtained by drying at 150°C and by extraction, using ethylic ether, and ashing at 500-600°C. The amino acid composition was obtained by liquid chromatography. Maral meat, with a pH of 5.85 and an average moisture content of 76.82%, was found to be low in fat (2.26%). Its protein content was 18.71% while its ash content was 2.21%. The amino acid composition showed that lysine (9.85 g/100 g), threonine (5.38 g/100 g), and valine (5.84 g/100 g) predominated in maral meat, while phenylalanine (4.08 g/100 g), methionine (3.29 g/100 g), and tryptophan (0.94 g/100 g) were relatively low in maral meat compared to other meats. The average WBC was found to be 65.82% and WBC was found to inversely correlate with moisture content. Low-fat content, high mineral content, and balanced amino-acid composition qualify maral meat as a worthy dietary and functional food.

Capillary electrophoresis coupled with mass spectrometry for the evaluation of substance P enzymatic degradation by SaOS-2 human osteosarcoma.

PubMed

Cavazza, Antonella; Corradini, Claudio; Marini, Mario; Roda, Luigi Giorgio; Valenti, Angela

2011-09-01

A new analytical method for the detection and the quantitative evaluation of the undecapeptide substance P by capillary electrophoresis coupled with ion trap mass spectrometry (CE-MS) by a co-axial sheath liquid interface has been developed. Conditions of analysis employed an acidic buffer and a 60 cm fused silica capillary installed by overcoming the UV window position, thus allowing to perform the analysis in a brief time. The method has been applied to the evaluation of substance P enzymatic hydrolysis during incubation with the human osteosarcoma SaOS-2 cell line. The analysis of amino acids derived from the cleavage of substance P has been also carried out simultaneously under the same electrophoretic conditions allowing the description of a kinetic of amino acid formation, parallel with substance P disappearance. The amounts of intact substance P and of free amino acids were monitored along 600 s of incubation time. A steady decrease of substance P as function of reaction time was observed. Peptide's half-life was found to be about 4.3s, indicating an extremely fast hydrolysis in the presence of the SaOS-2 cells. Proline, phenilalanine and methionine were the predominant free amino acids recorded. Obtained results lead to hypothesize the occurrence of endopeptidases activity, followed by aminopeptidases responsible for the release of free amino acids originated after primary bond cleavage. Copyright © 2011 Elsevier B.V. All rights reserved.

Study of morphology, chemical, and amino acid composition of red deer meat

PubMed Central

Okuskhanova, Eleonora; Assenova, Bahytkul; Rebezov, Maksim; Amirkhanov, Kumarbek; Yessimbekov, Zhanibek; Smolnikova, Farida; Nurgazezova, Almagul; Nurymkhan, Gulnur; Stuart, Marilyne

2017-01-01

Aim: The aim of this study was to evaluate red deer (maral) meat quality based on chemical composition, pH, water-binding capacity (WBC), and amino acid content. Materials and Methods: Maral meat surface morphology measurements were obtained by scanning electron microscopy. Active acidity (pH) was determined by potentiometry. Samples were analyzed for WBC by exudation of moisture to a filter paper by the application of pressure. Chemical composition (moisture, protein, fat, and ash fractions) was obtained by drying at 150°C and by extraction, using ethylic ether, and ashing at 500-600°C. The amino acid composition was obtained by liquid chromatography. Results: Maral meat, with a pH of 5.85 and an average moisture content of 76.82%, was found to be low in fat (2.26%). Its protein content was 18.71% while its ash content was 2.21%. The amino acid composition showed that lysine (9.85 g/100 g), threonine (5.38 g/100 g), and valine (5.84 g/100 g) predominated in maral meat, while phenylalanine (4.08 g/100 g), methionine (3.29 g/100 g), and tryptophan (0.94 g/100 g) were relatively low in maral meat compared to other meats. The average WBC was found to be 65.82% and WBC was found to inversely correlate with moisture content. Conclusion: Low-fat content, high mineral content, and balanced amino-acid composition qualify maral meat as a worthy dietary and functional food. PMID:28717313

Amino Acid and Vitamin Requirements of Several Bacteroides Strains

PubMed Central

Quinto, Grace

1966-01-01

Nutritional studies were performed on nine Bacteroides strains, by use of the methodology and media of anaerobic rumen microbiology. Ristella perfoetens CCI required l-arginine hydrochloride, l-tryptophan, l-leucine, l-histidine hydrochloride, l-cysteine hydrochloride, dl-valine, dl-tyrosine, and the vitamin calcium-d-pantothenate, since scant turbidity developed in media without these nutrients. R. perfoetens was stimulated by glycine, dl-lysine hydrochloride, dl-isoleucine, l-proline, l-glutamic acid, dl-alanine, dl-phenylalanine, dl-methionine, and the vitamins nicotinamide and p-aminobenzoic acid, since maximal turbidity developed more slowly in media without these nutrients than in complete medium. Medium A-23, which was devised for R. perfoetens, contained salts, 0.0002% nicotinamide and calcium d-pantothenate, 0.00001% p-aminobenzoic acid, 0.044% l-tryptophan, 0.09% l-glutamic acid, and 0.1% of the other 13 amino acids listed above. Zuberella clostridiformis and seven strains of R. pseudoinsolita did not require vitamins, and showed no absolute requirement for any one amino acid. Various strains produced maximal turbidity more slowly in media deficient in l-proline, glycine, l-glutamic acid, dl-serine, l-histidine hydrochloride, dl-alanine, or l-cysteine hydrochloride, than in complete medium. These eight strains grew optimally in medium A-23 plus 0.1% dl-serine but without vitamins. PMID:16349673

Low levels of serum serotonin and amino acids identified in migraine patients.

PubMed

Ren, Caixia; Liu, Jia; Zhou, Juntuo; Liang, Hui; Wang, Yayun; Sun, Yinping; Ma, Bin; Yin, Yuxin

2018-02-05

Migraine is a highly disabling primary headache associated with a high socioeconomic burden and a generally high prevalence. The clinical management of migraine remains a challenge. This study was undertaken to identify potential serum biomarkers of migraine. Using Liquid Chromatography coupled to Mass Spectrometry (LC-MS), the metabolomic profile of migraine was compared with healthy individuals. Principal component analysis (PCA) and Orthogonal partial least squares-discriminant analysis (orthoPLS-DA) showed the metabolomic profile of migraine is distinguishable from controls. Volcano plot analysis identified 10 serum metabolites significantly decreased during migraine. One of these was serotonin, and the other 9 were amino acids. Pathway analysis and enrichment analysis showed tryptophan metabolism (serotonin metabolism), arginine and proline metabolism, and aminoacyl-tRNA biosynthesis are the three most prominently altered pathways in migraine. ROC curve analysis indicated Glycyl-l-proline, N-Methyl-dl-Alanine and l-Methionine are potential sensitive and specific biomarkers for migraine. Our results show Glycyl-l-proline, N-Methyl-dl-Alanine and l-Methionine may be as specific or more specific for migraine than serotonin which is the traditional biomarker of migraine. We propose that therapeutic manipulation of these metabolites or metabolic pathways may be helpful in the prevention and treatment of migraine. Copyright © 2018 Elsevier Inc. All rights reserved.

Nutriepigenetic regulation by folate-homocysteine-methionine axis: a review.

PubMed

Bhargava, Seema; Tyagi, S C

2014-02-01

Although normally folic acid is given during pregnancy, presumably to prevent neural tube defects, the mechanisms of this protection are unknown. More importantly it is unclear whether folic acid has other function during development. It is known that folic acid re-methylates homocysteine (Hcy) to methionine by methylene tetrahydrofolate reductase-dependent pathways. Folic acid also generates high-energy phosphates, behaves as an antioxidant and improves nitric oxide (NO) production by endothelial NO synthase. Interestingly, during epigenetic modification, methylation of DNA/RNA generate homocysteine unequivocally. The enhanced overexpression of methyl transferase lead to increased yield of Hcy. The accumulation of Hcy causes vascular dysfunction, reduces perfusion in the muscles thereby causing musculopathy. Another interesting fact is that children with severe hyperhomocysteinaemia (HHcy) have skeletal deformities, and do not live past teenage. HHcy is also associated with the progeria syndrome. Epilepsy is primarily caused by inhibition of gamma-amino-butyric-acid (GABA) receptor, an inhibitory neurotransmitter in the neuronal synapse. Folate deficiency leads to HHcy which then competes with GABA for binding on the GABA receptors. With so many genetic and clinical manifestations associated with folate deficiency, we propose that folate deficiency induces epigenetic alterations in the genes and thereby results in disease.

Ammonia and amino acid profiles in liver cirrhosis: effects of variables leading to hepatic encephalopathy.

PubMed

Holecek, Milan

2015-01-01

Hyperammonemia and severe amino acid imbalances play central role in hepatic encephalopathy (HE). In the article is demonstrated that the main source of ammonia in cirrhotic subjects is activated breakdown of glutamine (GLN) in enterocytes and the kidneys and the main source of GLN is ammonia detoxification to GLN in the brain and skeletal muscle. Branched-chain amino acids (BCAA; valine, leucine, and isoleucine) decrease due to activated GLN synthesis in muscle. Aromatic amino acids (AAA; phenylalanine, tyrosine, and tryptophan) and methionine increase due to portosystemic shunts and reduced ability of diseased liver. The effects on aminoacidemia of the following variables that may affect the course of liver disease are discussed: nutritional status, starvation, protein intake, inflammation, acute hepatocellular damage, bleeding from varices, portosystemic shunts, hepatic cancer, and renal failure. It is concluded that (1) neither ammonia nor amino acid concentrations correlate closely with the severity of liver disease; (2) BCAA/AAA ratio could be used as a good index of liver impairment and for early detection of derangements in amino acid metabolism; (3) variables potentially leading to overt encephalopathy exert substantial but uneven effects; and (4) careful monitoring of ammonia and aminoacidemia may discover important break points in the course of liver disease and indicate appropriate therapeutic approach. Of special importance might be isoleucine deficiency in bleeding from varices, arginine deficiency in sepsis, and a marked rise of GLN and ammonia levels that may appear in all events leading to HE. Copyright © 2015 Elsevier Inc. All rights reserved.

Metabolomic analysis reveals altered skeletal muscle amino acid and fatty acid handling in obese humans.

PubMed

Baker, Peter R; Boyle, Kristen E; Koves, Timothy R; Ilkayeva, Olga R; Muoio, Deborah M; Houmard, Joseph A; Friedman, Jacob E

2015-05-01

Investigate the effects of obesity and high-fat diet (HFD) exposure on fatty acid oxidation and TCA cycle intermediates and amino acids in skeletal muscle to better characterize energy metabolism. Plasma and skeletal muscle metabolomic profiles were measured from lean and obese males before and after a 5-day HFD in the 4 h postprandial condition. At both time points, plasma short-chain acylcarnitine species (SCAC) were higher in the obese subjects, while the amino acids glycine, histidine, methionine, and citrulline were lower in skeletal muscle of obese subjects. Skeletal muscle medium-chain acylcarnitines (MCAC) C6, C8, C10:2, C10:1, C10, and C12:1 increased in obese subjects, but decreased in lean subjects, from pre- to post-HFD. Plasma content of C10:1 was also decreased in the lean but increased in the obese subjects from pre- to post-HFD. CD36 increased from pre- to post-HFD in obese but not lean subjects. Lower skeletal muscle amino acid content and accumulation of plasma SCAC in obese subjects could reflect increased anaplerosis for TCA cycle intermediates, while accumulation of MCAC suggests limitations in β-oxidation. These measures may be important markers of or contributors to dysregulated metabolism observed in skeletal muscle of obese humans. © 2015 The Obesity Society.

Isocyanides Derived from α,α-Disubstituted Amino Acids: Synthesis and Antifouling Activity Assessment.

PubMed

Inoue, Yuki; Takashima, Shuhei; Nogata, Yasuyuki; Yoshimura, Erina; Chiba, Kazuhiro; Kitano, Yoshikazu

2018-03-01

Herein, we contribute to the development of environmentally friendly antifoulants by synthesizing eighteen isocyanides derived from α,α-disubstituted amino acids and evaluating their antifouling activity/toxicity against the cypris larvae of the Balanus amphitrite barnacle. Almost all isocyanides showed good antifouling activity without significant toxicity and exhibited EC 50 values of 0.07 - 7.30 μg/mL after 120-h exposure. The lowest EC 50 values were observed for valine-, methionine-, and phenylalanine-derived isocyanides, which achieved > 95% cypris larvae settlement inhibition at concentrations of less than 30 μg/mL without exhibiting significant toxicity. Thus, the prepared isocyanides should be useful for further research focused on the development of environmentally friendly antifouling agents. © 2018 Wiley-VHCA AG, Zurich, Switzerland.

PLASMA PROTEIN AND HEMOGLOBIN PRODUCTION

PubMed Central

Robscheit-Robbins, F. S.; Miller, L. L.; Whipple, G. H.

1947-01-01

Given healthy dogs fed abundant iron and protein-free or low protein diets with sustained anemia and hypoproteinemia, we can study the capacity of these animals to produce simultaneously new hemoglobin and plasma protein. Reserve stores of blood protein-building materials are measurably depleted and levels of 6 to 8 gm. per cent for hemoglobin and 4 to 5 gm. per cent for plasma protein can be maintained for weeks or months depending upon the intake of food proteins or amino acid mixtures. These dogs are very susceptible to infection and various poisons. Dogs tire of these diets and loss of appetite terminates many experiments. Under these conditions (double depletion) standard growth mixtures of essential amino acids are tested to show the response in blood protein output and urinary nitrogen balance. As a part of each tabulated experiment one of the essential amino acids is deleted from the complete growth mixture to compare such response with that of the whole mixture. Methionine, threonine, phenylalanine, and tryptophane when singly eliminated from the complete amino acid mixture do effect a sharp rise in urinary nitrogen. This loss of urinary nitrogen is corrected when the individual amino acid is replaced in the mixture. Histidine, lysine, and valine have a moderate influence upon urinary nitrogen balance toward nitrogen conservation. Leucine, isoleucine, and arginine have minimal or no effect upon urinary nitrogen balance when these individual amino acids are deleted from the complete growth mixture of amino acids during 3 to 4 week periods. Tryptophane and to a less extent phenylalanine and threonine when returned to the amino acid mixture are associated with a conspicuous preponderance of plasma protein output over the hemoglobin output (Table 4). Arginine, lysine, and histidine when returned to the amino acid mixture are associated with a large preponderance of hemoglobin output. Various amino acid mixtures under these conditions may give a positive urinary nitrogen balance and a liberal output of blood proteins but there is always weight loss, however we may choose to explain this loss. These experiments touch on the complex problems of parenteral nutrition, experimental and clinical. PMID:19871612

Evaluation of Prostate Cancer with Radiolabeled Amino Acid Analogs.

PubMed

Schuster, David M; Nanni, Cristina; Fanti, Stefano

2016-10-01

Conventional imaging of prostate cancer has limitations related to the frequently indolent biology of the disease. PET is a functional imaging method that can exploit various aspects of tumor biology to enable greater detection of prostate cancer than can be provided by morphologic imaging alone. Radiotracers that are in use or under investigation for targeting salient features of prostate cancer include those directed to glucose, choline, acetate, prostate-specific membrane antigen, bombesin, and amino acids. The tumor imaging features of this last class of radiotracers mirror the upregulation of transmembrane amino acid transport that is necessary in carcinomas because of increased amino acid use for energy requirements and protein synthesis. Natural and synthetic amino acids radiolabeled for PET imaging have been investigated in prostate cancer patients. Early work with naturally occurring amino acid-derived radiotracers, such as l- 11 C-methionine and l-1- 11 C-5-hydroxytryptophan, demonstrated promising results, including greater sensitivity than 18 F-FDG for intraprostatic and extraprostatic cancer detection. However, limitations with naturally occurring amino acid-derived compounds, including metabolism of the radiotracer itself, led to the development of synthetic amino acid radiotracers, which are not metabolized and therefore more accurately reflect transmembrane amino acid transport. Of the synthetic amino acid-derived PET radiotracers, anti-1-amino-3- 18 F-fluorocyclobutane-1-carboxylic acid ( 18 F-FACBC or 18 F-fluciclovine) has undergone the most promising translation to human use, including the availability of simplified radiosynthesis. Several studies have indicated advantageous biodistribution in the abdomen and pelvis with little renal excretion and bladder activity-characteristics beneficial for prostate cancer imaging. Studies have demonstrated improved lesion detection and diagnostic performance of 18 F-fluciclovine in comparison with conventional imaging, especially for recurrent prostate cancer, although issues with nonspecific uptake limit the potential role of 18 F-fluciclovine in the diagnosis of primary prostate cancer. Although work is ongoing, recently published intrapatient comparisons of 18 F-fluciclovine with 11 C-choline reported higher overall diagnostic performance of the former, especially for the detection of disease relapse. This review is aimed at providing a detailed overview of amino acid-derived PET compounds that have been studied for use in prostate cancer imaging. © 2016 by the Society of Nuclear Medicine and Molecular Imaging, Inc.

Dealing with methionine/homocysteine sulfur: cysteine metabolism to taurine and inorganic sulfur

PubMed Central

Ueki, Iori

2010-01-01

Synthesis of cysteine as a product of the transsulfuration pathway can be viewed as part of methionine or homocysteine degradation, with cysteine being the vehicle for sulfur conversion to end products (sulfate, taurine) that can be excreted in the urine. Transsulfuration is regulated by stimulation of cystathionine β-synthase and inhibition of methylene tetrahydrofolate reductase in response to changes in the level of S-adenosylmethionine, and this promotes homocysteine degradation when methionine availability is high. Cysteine is catabolized by several desulfuration reactions that release sulfur in a reduced oxidation state, generating sulfane sulfur or hydrogen sulfide (H2S), which can be further oxidized to sulfate. Cysteine desulfuration is accomplished by alternate reactions catalyzed by cystathionine β-synthase and cystathionine γ-lyase. Cysteine is also catabolized by pathways that require the initial oxidation of the cysteine thiol by cysteine dioxygenase to form cysteinesulfinate. The oxidative pathway leads to production of taurine and sulfate in a ratio of approximately 2:1. Relative metabolism of cysteine by desulfuration versus oxidative pathways is influenced by cysteine dioxygenase activity, which is low in animals fed low-protein diets and high in animals fed excess sulfur amino acids. Thus, desulfuration reactions dominate when cysteine is deficient, whereas oxidative catabolism dominates when cysteine is in excess. In rats consuming a diet with an adequate level of sulfur amino acids, about two thirds of cysteine catabolism occurs by oxidative pathways and one third by desulfuration pathways. Cysteine dioxygenase is robustly regulated in response to cysteine availability and may function to provide a pathway to siphon cysteine to less toxic metabolites than those produced by cysteine desulfuration reactions. PMID:20162368

LAT1 targeted delivery of methionine based imaging probe derived from M(III) metal ions for early diagnosis of proliferating tumours using molecular imaging modalities.

PubMed

Hazari, Puja Panwar; Prakash, Surbhi; Meena, Virendra K; Jaswal, Ambika; Khurana, Harleen; Mishra, Surabhi Kirti; Bhonsle, Hemanth Kumar; Singh, Lokendra; Mishra, Anil K

2015-01-01

We investigated the potential of DTPA-bis(Methionine), a target specific amino acid based probe for detection of L-type amino acid transporters (LAT1) known to over express in proliferating tumours using multimodality imaging. The ligand, DTPA-bis(Met) was readily converted to lanthanide complexes and was found capable of targeting cancer cells using multimodality imaging. DTPA-bis(Met) complexes were synthesized and characterized by mass spectroscopy. MR longitudinal relaxivity, r₁ = 4.067 ± 0.31 mM⁻¹s⁻¹ and transverse relaxivity, r₂ = 8.61 ± 0.07 mM⁻¹s⁻¹ of Gd(III)-DTPA-bis(Met) were observed at pH 7.4 at 7 T. Bright, localized fluorescence of Eu(III)-DTPA-bis(Met) was observed with standard microscopy and displacement studies indicated ligand functionality. K(D) value determined for Eu(III)-DTPA-bis(Met) on U-87 MG cells was found to be 17.3 pM and showed appreciable fluorescence within the cells. Radio HPLC showed a radiochemical purity more than 95% (specific activity = 400-500 MBq/μmol, labelling efficiency 78 %) for ⁶⁸Ga(III)-DTPA-bis(Met). Pre-treatment of xenografted U-87 MG athymic mice with ⁶⁸Ga(III)-DTPA-bis(Met) following unlabelled L-methionine administration reduced tumour uptake by 10-folds in Micro PET. These data support the specific binding of ⁶⁸Ga(III)-DTPA-bis(Met) to the LAT1 transporter. To summarize, this agent possesses high stability in biological environment and exhibits effective interaction with its LAT1 transporters giving high accumulation in tumour area, excellent tumour/non-tumour ratio and low non-specific retention in vivo.

To supplement or not to supplement: a metabolic network framework for human nutritional supplements.

PubMed

Nogiec, Christopher D; Kasif, Simon

2013-01-01

Flux balance analysis and constraint based modeling have been successfully used in the past to elucidate the metabolism of single cellular organisms. However, limited work has been done with multicellular organisms and even less with humans. The focus of this paper is to present a novel use of this technique by investigating human nutrition, a challenging field of study. Specifically, we present a steady state constraint based model of skeletal muscle tissue to investigate amino acid supplementation's effect on protein synthesis. We implement several in silico supplementation strategies to study whether amino acid supplementation might be beneficial for increasing muscle contractile protein synthesis. Concurrent with published data on amino acid supplementation's effect on protein synthesis in a post resistance exercise state, our results suggest that increasing bioavailability of methionine, arginine, and the branched-chain amino acids can increase the flux of contractile protein synthesis. The study also suggests that a common commercial supplement, glutamine, is not an effective supplement in the context of increasing protein synthesis and thus, muscle mass. Similar to any study in a model organism, the computational modeling of this research has some limitations. Thus, this paper introduces the prospect of using systems biology as a framework to formally investigate how supplementation and nutrition can affect human metabolism and physiology.

Construction of a D-amino acid oxidase reactor based on magnetic nanoparticles modified by a reactive polymer and its application in screening enzyme inhibitors.

PubMed

Mu, Xiaoyu; Qiao, Juan; Qi, Li; Liu, Ying; Ma, Huimin

2014-08-13

Developing facile and high-throughput methods for exploring pharmacological inhibitors of D-amino acid oxidase (DAAO) has triggered increasing interest. In this work, DAAO was immobilized on the magnetic nanoparticles, which were modified by a biocompatible reactive polymer, poly(glycidyl methacrylate) (PGMA) via an atom transfer radical polymerization technique. Interestingly, the enzyme immobilization process was greatly promoted with the assistance of a lithium perchlorate catalyst. Meanwhile, a new amino acid ionic liquid (AAIL) was successfully synthesized and employed as the efficient chiral ligand in a chiral ligand exchange capillary electrophoresis (CLE-CE) system for chiral separation of amino acids (AAs) and quantitation of methionine, which was selected as the substrate of DAAO. Then, the apparent Michaelis-Menten constants in the enzyme system were determined with the proposed CLE-CE method. The prepared DAAO-PGMA-Fe3O4 nanoparticles exhibited excellent reusability and good stability. Moreover, the enzyme reactor was successfully applied in screening DAAO inhibitors. These results demonstrated that the enzyme could be efficiently immobilized on the polymer-grafted magnetic nanoparticles and that the obtained enzyme reactor has great potential in screening enzyme inhibitors, further offering new insight into monitoring the relevant diseases.

Effects of essential amino acids on lipid metabolism in mice and humans.

PubMed

Xiao, Fei; Du, Ying; Lv, Ziquan; Chen, Shanghai; Zhu, Jianmin; Sheng, Hongguang; Guo, Feifan

2016-11-01

Eight amino acids are considered essential for human nutrition, and three of them, including leucine, isoleucine and valine, are called as branched-chain amino acids (BCAAs). We recently discovered that dietary deficiency of any BCAA for 7 days rapidly reduces the abdominal fat mass in mice. The goal of this study was to investigate (1) whether dietary deficiency of the other five essential amino acids (EAAs), including phenylalanine, threonine, tryptophan, methionine and lysine, would produce similar effects and (2) whether an association between serum AAs and obesity was observed in humans in Chinese Han population. Similar to BCAAs deprivation, dietary deficiency of any of these five EAAs for 7 days significantly reduced abdominal fat mass, which is likely caused by increased energy expenditure. Expression of genes and proteins related to lipolysis, however, were differentially regulated by different EAAs. These results suggest a crucial role of EAAs deprivation on lipid metabolism in mice. Our human studies revealed that levels of four EAAs (leucine, isoleucine, valine and phenylalanine) were elevated in obese humans compared with those in lean controls in Chinese Han population. Based on the results obtained from mice, we speculate that these four EAAs might play important roles in human obesity. © 2016 Society for Endocrinology.

The specific features of methionine biosynthesis and metabolism in plants

PubMed Central

Ravanel, Stéphane; Gakière, Bertrand; Job, Dominique; Douce, Roland

1998-01-01

Plants, unlike other higher eukaryotes, possess all the necessary enzymatic equipment for de novo synthesis of methionine, an amino acid that supports additional roles than simply serving as a building block for protein synthesis. This is because methionine is the immediate precursor of S-adenosylmethionine (AdoMet), which plays numerous roles of being the major methyl-group donor in transmethylation reactions and an intermediate in the biosynthesis of polyamines and of the phytohormone ethylene. In addition, AdoMet has regulatory function in plants behaving as an allosteric activator of threonine synthase. Among the AdoMet-dependent reactions occurring in plants, methylation of cytosine residues in DNA has raised recent interest because impediment of this function alters plant morphology and induces homeotic alterations in flower organs. Also, AdoMet metabolism seems somehow implicated in plant growth via an as yet fully understood link with plant-growth hormones such as cytokinins and auxin and in plant pathogen interactions. Because of this central role in cellular metabolism, a precise knowledge of the biosynthetic pathways that are responsible for homeostatic regulation of methionine and AdoMet in plants has practical implications, particularly in herbicide design. PMID:9636232

Mitochondrial targeting of the human peptide methionine sulfoxide reductase (MSRA), an enzyme involved in the repair of oxidized proteins.

PubMed

Hansel, Alfred; Kuschel, Lioba; Hehl, Solveig; Lemke, Cornelius; Agricola, Hans-Jürgen; Hoshi, Toshinori; Heinemann, Stefan H

2002-06-01

Peptide methionine sulfoxide reductase (MSRA) catalyzes the reduction of methionine sulfoxide to methionine. This widely expressed enzyme constitutes an important repair mechanism for oxidatively damaged proteins, which accumulate during the manifestation of certain degenerative diseases and aging processes. In addition, it is discussed to be involved in regulatory processes. Here we address the question of how the enzyme's diverse functions are reflected in its subcellular localization. Using fusions of the human version of MSRA with the enhanced green fluorescence protein expressed in various mammalian cell lines, we show a distinct localization at mitochondria. The N-terminal 23 amino acid residues contain the signal for this mitochondrial targeting. Activity tests showed that they are not required for enzyme function. Mitochondrial localization of native MSRA in mouse and rat liver slices was verified with an MSRA-specific antibody by using immunohistochemical methods. The protein was located in the mitochondrial matrix, as demonstrated by using pre-embedding immunostaining and electron microscopy. Mitochondria are the major source of reactive oxygen species (ROS). Therefore, MSRA has to be considered an important means for the general reduction of ROS release from mitochondria.

Methionine Sulfoxide Reductase A (MsrA) and Its Function in Ubiquitin-Like Protein Modification in Archaea

DOE PAGES

Fu, Xian; Adams, Zachary; Liu, Rui; ...

2017-09-05

Methionine sulfoxide reductase A (MsrA) is an antioxidant enzyme found in all domains of life that catalyzes the reduction of methionine-S-sulfoxide (MSO) to methionine in proteins and free amino acids. We demonstrate that archaeal MsrA has a ubiquitin-like (Ubl) protein modification activity that is distinct from its stereospecific reduction of MSO residues. MsrA catalyzes this Ubl modification activity, with the Ubl-activating E1 UbaA, in the presence of the mild oxidant dimethyl sulfoxide (DMSO) and in the absence of reductant. In contrast, the MSO reductase activity of MsrA is inhibited by DMSO and requires reductant. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysismore » reveals that MsrA-dependent Ubl conjugates are associated with DNA replication, protein remodeling, and oxidative stress and include the Ubl-modified MsrA, Orc3 (Orc1/Cdc6), and Cdc48d (Cdc48/p97 AAA+ ATPase). Overall, we found archaeal MsrA to have opposing MSO reductase and Ubl modifying activities that are associated with oxidative stress responses and controlled by exposure to mild oxidant.« less

Methionine Sulfoxide Reductase A (MsrA) and Its Function in Ubiquitin-Like Protein Modification in Archaea

DOE Office of Scientific and Technical Information (OSTI.GOV)

Fu, Xian; Adams, Zachary; Liu, Rui

Methionine sulfoxide reductase A (MsrA) is an antioxidant enzyme found in all domains of life that catalyzes the reduction of methionine-S-sulfoxide (MSO) to methionine in proteins and free amino acids. We demonstrate that archaeal MsrA has a ubiquitin-like (Ubl) protein modification activity that is distinct from its stereospecific reduction of MSO residues. MsrA catalyzes this Ubl modification activity, with the Ubl-activating E1 UbaA, in the presence of the mild oxidant dimethyl sulfoxide (DMSO) and in the absence of reductant. In contrast, the MSO reductase activity of MsrA is inhibited by DMSO and requires reductant. Liquid chromatography-tandem mass spectrometry (LC-MS/MS) analysismore » reveals that MsrA-dependent Ubl conjugates are associated with DNA replication, protein remodeling, and oxidative stress and include the Ubl-modified MsrA, Orc3 (Orc1/Cdc6), and Cdc48d (Cdc48/p97 AAA+ ATPase). Overall, we found archaeal MsrA to have opposing MSO reductase and Ubl modifying activities that are associated with oxidative stress responses and controlled by exposure to mild oxidant.« less

Effect of Eicosapentaenoic acid (EPA) supplementation on cardiovascular markers in patients with type 2 diabetes mellitus: A randomized, double-blind, placebo-controlled trial.

PubMed

Golzari, Mohammad Hassan; Javanbakht, Mohammad Hassan; Ghaedi, Ehsan; Mohammadi, Hamed; Djalali, Mahmoud

2018-05-01

Cardiovascular complications are one of main cause of increased mortality and morbidity among Diabetes Mellitus (DM) patients. Altered metabolism of sulphur amino acids in diabetes reflected as increases in concentration of methionine and cysteine/cystine in the blood which known as a markers of Cardiovascular Diseases (CVD). The aim of present study was to determine the effect of Eicosapentaenoic acid (EPA) supplementation on sulfhydryl amino acids and Atherogenic Index of Plasma (AIP) in patients with type 2 DM (T2DM). A randomized, double-blind, placebo-controlled clinical trial was performed in 36 control and patients with DM. The subjects were randomly assigned to obtain 2 g/d EPA (n = 18) or placebo (n = 18) for 8 weeks. Fasting serum level of Cystein and Methionine were measured using HPLC method and atherogenic index of plasma (AIP) as a proxy measure of atherosclerosis was computed. Eight weeks supplementation with EPA led to significant reductions in Met (p < 0.002) and Cys (p < 0.001) compared with the placebo (p < 0.06). In addition, compared to placebo a significant reduction in AIP were seen after taking EPA (p < 0.04). EPA supplementation in patients with T2DM for eight weeks had beneficial effects on Met, Cys and AIP, which may attribute to the prevention of vascular complications in the T2DM patients. Copyright © 2018 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Feeding Preferences and the Nutritional Value of Tropical Algae for the Abalone Haliotis asinina

PubMed Central

Angell, Alex R.; Pirozzi, Igor; de Nys, Rocky; Paul, Nicholas A.

2012-01-01

Understanding the feeding preferences of abalone (high-value marine herbivores) is integral to new species development in aquaculture because of the expected link between preference and performance. Performance relates directly to the nutritional value of algae – or any feedstock – which in turn is driven by the amino acid content and profile, and specifically the content of the limiting essential amino acids. However, the relationship between feeding preferences, consumption and amino acid content of algae have rarely been simultaneously investigated for abalone, and never for the emerging target species Haliotis asinina. Here we found that the tropical H. asinina had strong and consistent preferences for the red alga Hypnea pannosa and the green alga Ulva flexuosa, but no overarching relationship between protein content (sum of amino acids) and preference existed. For example, preferred Hypnea and Ulva had distinctly different protein contents (12.64 vs. 2.99 g 100 g−1) and the protein-rich Asparagopsis taxiformis (>15 g 100 g−1 of dry weight) was one of the least preferred algae. The limiting amino acid in all algae was methionine, followed by histidine or lysine. Furthermore we demonstrated that preferences can largely be removed using carrageenan as a binder for dried alga, most likely acting as a feeding attractant or stimulant. The apparent decoupling between feeding preference and algal nutritive values may be due to a trade off between nutritive values and grazing deterrence associated with physical and chemical properties. PMID:22719967

Limits to sulfur accumulation in transgenic lupin seeds expressing a foreign sulfur-rich protein.

PubMed

Tabe, Linda M; Droux, Michel

2002-03-01

The low sulfur amino acid content of legume seeds restricts their nutritive value for animals. We have investigated the limitations to the accumulation of sulfur amino acids in the storage proteins of narrow leaf lupin (Lupinus angustifolius) seeds. Variation in sulfur supply to lupin plants affected the sulfur amino acid accumulation in the mature seed. However, when sulfur was in abundant supply, it accumulated to a large extent in oxidized form, rather than reduced form, in the seeds. At all but severely limiting sulfur supply, addition of a transgenic (Tg) sink for organic sulfur resulted in an increase in seed sulfur amino acid content. We hypothesize that demand, or sink strength for organic sulfur, which is itself responsive to environmental sulfur supply, was the first limit to the methionine (Met) and cysteine (Cys) content of wild-type lupin seed protein under most growing conditions. In Tg, soil-grown seeds expressing a foreign Met- and Cys-rich protein, decreased pools of free Met, free Cys, and glutathione indicated that the rate of synthesis of sulfur amino acids in the cotyledon had become limiting. Homeostatic mechanisms similar to those mediating the responses of plants to environmental sulfur stress resulted in an adjustment of endogenous protein composition in Tg seeds, even when grown at adequate sulfur supply. Uptake of sulfur by lupin cotyledons, as indicated by total seed sulfur at maturity, responded positively to increased sulfur supply, but not to increased demand in the Tg seeds.

Limits to Sulfur Accumulation in Transgenic Lupin Seeds Expressing a Foreign Sulfur-Rich Protein

PubMed Central

Tabe, Linda M.; Droux, Michel

2002-01-01

The low sulfur amino acid content of legume seeds restricts their nutritive value for animals. We have investigated the limitations to the accumulation of sulfur amino acids in the storage proteins of narrow leaf lupin (Lupinus angustifolius) seeds. Variation in sulfur supply to lupin plants affected the sulfur amino acid accumulation in the mature seed. However, when sulfur was in abundant supply, it accumulated to a large extent in oxidized form, rather than reduced form, in the seeds. At all but severely limiting sulfur supply, addition of a transgenic (Tg) sink for organic sulfur resulted in an increase in seed sulfur amino acid content. We hypothesize that demand, or sink strength for organic sulfur, which is itself responsive to environmental sulfur supply, was the first limit to the methionine (Met) and cysteine (Cys) content of wild-type lupin seed protein under most growing conditions. In Tg, soil-grown seeds expressing a foreign Met- and Cys-rich protein, decreased pools of free Met, free Cys, and glutathione indicated that the rate of synthesis of sulfur amino acids in the cotyledon had become limiting. Homeostatic mechanisms similar to those mediating the responses of plants to environmental sulfur stress resulted in an adjustment of endogenous protein composition in Tg seeds, even when grown at adequate sulfur supply. Uptake of sulfur by lupin cotyledons, as indicated by total seed sulfur at maturity, responded positively to increased sulfur supply, but not to increased demand in the Tg seeds. PMID:11891268

Effects of replacing fish meal with soy protein concentrate and of DL-methionine supplementation in high-energy, extruded diets on the growth and nutrient utilization of rainbow trout, Oncorhynchus mykiss.

PubMed

Mambrini, M; Roem, A J; Carvèdi, J P; Lallès, J P; Kaushik, S J

1999-11-01

Our objectives were to test the potential replacement of fish meal by soy protein concentrate (SPC) in high-energy, extruded diets fed to rainbow trout (Oncorhynchus mykiss) and to evaluate the efficiency of DL-methionine supplementation of soy-based diets. Groups of trout (initial BW 103 to 106 g) were fed to visual satiety with isonitrogenous (6.6% DM) high-energy (22.8 MJ/kg DM gross energy), extruded diets, in which fish meal was progressively replaced with SPC (0, 50, 75, and 100%). Three 100% SPC diets were formulated to be either unsupplemented or supplemented with DL-methionine, so that total methionine content was .8 or 1.0% of DM. The quality of the SPC source used was assessed by measuring the antitryptic and antigenic activities and the concentrations of the isoflavones daidzein and genistein. Apparent digestibility of the diets was determined using the indirect method. A growth trial was conducted over 90 d at a water temperature of 18 degrees C. In addition to body composition analysis, plasma amino acid concentrations, anti-soy protein antibodies in the serum, and isoflavone concentrations in the bile were measured. The SPC source tested exhibited low antitryptic and antigenic activities, but it contained high concentrations of isoflavones (1,990 and 5,903 ppm for daidzein and genistein, respectively). Protein digestibility was high (92%) and was unaffected either the proportion of SPC in the diet or by DL-methionine supplementation. This was also true for the availability of amino acids, except phenylalanine. Digestibility of lipid and energy was reduced by 19% when SPC totally replaced fish meal. Growth rate was reduced when more than 50% of the dietary protein was of soy origin (daily growth coefficient of 3.2 and 2.1% for the control and the unsupplemented 100% SPC diet, respectively). The effect on growth was mainly explained by a general decline in feed intake (13.7 and 12.0 g DM x kg BW(-1) x d(-1) for the control and the unsupplemented 100% SPC diet, respectively) and in lipid and, thus, in energy digestibility. The DL-methionine supplementation partially reversed the depressive effects of high dietary SPC incorporation (+13% growth), mainly by enhancing intake. The negative effect of SPC incorporation either may be due to the high isoflavone concentration or to an interaction between the soy protein component and the dietary lipids.

Pt(ii) coordination complexes as visible light photocatalysts for the oxidation of sulfides using batch and flow processes.

PubMed

Casado-Sánchez, Antonio; Gómez-Ballesteros, Rocío; Tato, Francisco; Soriano, Francisco J; Pascual-Coca, Gustavo; Cabrera, Silvia; Alemán, José

2016-07-12

A new catalytic system for the photooxidation of sulfides based on Pt(ii) complexes is presented. The catalyst is capable of oxidizing a large number of sulfides containing aryl, alkyl, allyl, benzyl, as well as more complex structures such as heterocycles and methionine amino acid, with complete chemoselectivity. In addition, the first sulfur oxidation in a continuous flow process has been developed.

Kinetics of acid hydrolysis and reactivity of some antibacterial hydrophilic iron(II) imino-complexes

NASA Astrophysics Data System (ADS)

Shaker, Ali Mohamed; Nassr, Lobna Abdel-Mohsen Ebaid; Adam, Mohamed Shaker Saied; Mohamed, Ibrahim Mohamed Abdelhalim

2015-05-01

Kinetic study of acid hydrolysis of some hydrophilic Fe(II) Schiff base amino acid complexes with antibacterial properties was performed using spectrophotometry. The Schiff base ligands were derived from sodium 2-hydroxybenzaldehyde-5-sulfonate and glycine, L-alanine, L-leucine, L-isoleucine, DL-methionine, DL-serine, or L-phenylalanine. The reaction was studied in aqueous media under conditions of pseudo-first order kinetics. Moreover, the acid hydrolysis was studied at different temperatures and the activation parameters were calculated. The general rate equation was suggested as follows: rate = k obs [Complex], where k obs = k 2 [H+]. The evaluated rate constants and activation parameters are consistent with the hydrophilicity of the investigated complexes.

Amino acid substitutions in the heptad repeat A and C regions of the F protein responsible for neurovirulence of measles virus Osaka-1 strain from a patient with subacute sclerosing panencephalitis.

PubMed

Ayata, Minoru; Tanaka, Miyuu; Kameoka, Kazuo; Kuwamura, Mitsuru; Takeuchi, Kaoru; Takeda, Makoto; Kanou, Kazuhiko; Ogura, Hisashi

2016-01-01

Measles virus (MV) is the causative agent of subacute sclerosing panencephalitis (SSPE). We previously reported that the F gene of the SSPE Osaka-2 strain is the major determinant of MV neurovirulence. Because the sites and extents of mutations differ among SSPE strains, it is necessary to determine the mutations responsible for the SSPE-specific phenotypes of individual viral strain. In this study, recombinant viruses containing the envelope-associated genes from the SSPE Osaka-1 strain were generated in the IC323 wild-type MV background. Hamsters inoculated with MV containing the H gene of the Osaka-1 strain displayed hyperactivity and seizures, but usually recovered and survived. Hamsters inoculated with MV containing the F gene of the Osaka-1 strain displayed severe neurologic signs and died. Amino acid substitutions in the heptad repeat A and C regions of the F protein, including a methionine-to-valine substitution at amino acid 94, play major roles in neurovirulence. Copyright © 2015 Elsevier Inc. All rights reserved.

Biocompatible silver nanoparticles prepared with amino acids and a green method.

PubMed

de Matos, Ricardo Almeida; Courrol, Lilia Coronato

2017-02-01

The synthesis of nanoparticles is usually carried out by chemical reduction, which is effective but uses many toxic substances, making the process potentially harmful to the environment. Hence, as part of the search for environmentally friendly or green synthetic methods, this study aimed to produce silver nanoparticles (AgNPs) using only AgNO 3 , Milli-Q water, white light from a xenon lamp (Xe) and amino acids. Nanoparticles were synthetized using 21 amino acids, and the shapes and sizes of the resultant nanoparticles were evaluated. The products were characterized by UV-Vis, zeta potential measurements and transmission electron microscopy. The synthesis of silver nanoparticles with tryptophan and tyrosine, methionine, cystine and histidine was possible through photoreduction method. Spherical nanoparticles were produced, with sizes ranging from 15 to 30 nm. Tryptophan does not require illumination nor heating, and the solution color changes immediately after the mixing of reagents if sodium hydroxide is added to the solution (pH = 10). The Xe illumination acts as sodium hydroxide in the nanoparticles synthesis, releases H + and allows the reduction of silver ions (Ag + ) in metallic silver (Ag 0 ).

Methionine restriction inhibits chemically-induced malignant transformation in the BALB/c 3T3 cell transformation assay.

PubMed

Nicken, Petra; Empl, Michael T; Gerhard, Daniel; Hausmann, Julia; Steinberg, Pablo

2016-09-01

High consumption of red meat entails a higher risk of developing colorectal cancer. Methionine, which is more frequently a component of animal proteins, and folic acid are members of the one carbon cycle and as such important players in DNA methylation and cancer development. Therefore, dietary modifications involving altered methionine and folic acid content might inhibit colon cancer development. In the present study, the BALB/c 3T3 cell transformation assay was used to investigate whether methionine and folic acid are able to influence the malignant transformation of mouse fibroblasts after treatment with the known tumour initiator 3-methylcholanthrene. Three different methionine concentrations (representing a -40%, a "normal" and a +40% cell culture medium concentration, respectively) and two different folic acid concentrations (6 and 20 μM) were thereby investigated. Methionine restriction led to a decrease of type III foci, while enhancement of both methionine and folic acid did not significantly increase the cell transformation rate. Interestingly, the focus-lowering effect of methionine was only significant in conjunction with an elevated folic acid concentration. In summary, we conclude that the malignant transformation of mouse fibroblasts is influenced by methionine levels and that methionine restriction could be a possible approach to reduce cancer development. Copyright © 2016 Elsevier Ltd. All rights reserved.

ToF-SIMS and principal component analysis of lipids and amino acids from inflamed and dysplastic human colonic mucosa.

PubMed

Urbini, Marco; Petito, Valentina; de Notaristefani, Francesco; Scaldaferri, Franco; Gasbarrini, Antonio; Tortora, Luca

2017-10-01

Here, time of flight secondary ion mass spectrometry (ToF-SIMS) and multivariate analysis were combined to study the role of ulcerative colitis (UC), a type of inflammatory bowel disease (IBD), in the colon cancer progression. ToF-SIMS was used to obtain mass spectra and chemical maps from the mucosal surface of human normal (NC), inflamed (IC), and dysplastic (DC) colon tissues. Chemical mapping with a lateral resolution of ≈ 1 μm allowed to evaluate zonation of fatty acids and amino acids as well as the morphological condition of the intestinal glands. High mass resolution ToF-SIMS spectra showed chemical differences in lipid and amino acid composition as a function of pathological state. In positive ion mode, mono- (MAG), di- (DAG), and triacylglycerol (TAG) signals were detected in NC tissues, while in IC and DC tissues, the only cholesterol was present as lipid class representative. Signals from fatty acids, collected in negative ion mode, were subjected to principal component analysis (PCA). PCA showed a strict correlation between IC and DC samples, due to an increase of stearic, arachidonic, and linoleic acid. In the same way, differences in the amino acid composition were highlighted through multivariate analysis. PCA revealed that glutamic acid, leucine/isoleucine, and valine fragments are related to IC tissues. On the other hand, tyrosine, methionine, and tryptophan peaks contributed highly to the separation of DC tissues. Finally, a classification of NC, IC, and DC patients was also achieved through hierarchical cluster analysis of amino acid fragments. In this case, human colonic inflammation showed a stronger relationship with normal than dysplastic condition. Graphical Abstract ᅟ.

Feeding by emerald ash borer larvae induces systemic changes in black ash foliar chemistry.

PubMed

Chen, Yigen; Whitehill, Justin G A; Bonello, Pierluigi; Poland, Therese M

2011-11-01

The exotic wood-boring pest, emerald ash borer (EAB), Agrilus planipennis Fairmaire (Coleoptera: Buprestidae), has been threatening North American ash (Fraxinus spp.) resources, this being recognized since its first detection in Michigan, USA and Ontario, Canada in 2002. Ash trees are killed by larval feeding in the cambial region, which results in disruption of photosynthate and nutrient translocation. In this study, changes in volatile and non-volatile foliar phytochemicals of potted 2-yr-old black ash, Fraxinus nigra Marshall, seedlings were observed in response to EAB larval feeding in the main stem. EAB larval feeding affected levels of six compounds [hexanal, (E)-2-hexenal, (Z)-3-hexenyl acetate, (E)-β-ocimene, methyl salicylate, and (Z,E)-α-farnesene] with patterns of interaction depending upon compounds of interest and time of observation. Increased methyl salicylate emission suggests similarity in responses induced by EAB larval feeding and other phloem-feeding herbivores. Overall, EAB larval feeding suppressed (Z)-3-hexenyl acetate emission, elevated (E)-β-ocimene emission in the first 30days, but emissions leveled off thereafter, and generally increased the emission of (Z,E)-α-farnesene. Levels of carbohydrates and phenolics increased overall, while levels of proteins and most amino acids decreased in response to larval feeding. Twenty-three amino acids were consistently detected in the foliage of black ash. The three most abundant amino acids were aspartic acid, glutamic acid, glutamine, while the four least abundant were α-aminobutyric acid, β-aminoisobutyric acid, methionine, and sarcosine. Most (16) foliar free amino acids and 6 of the 9 detected essential amino acids decreased with EAB larval feeding. The ecological consequences of these dynamic phytochemical changes on herbivores harbored by ash trees and potential natural enemies of these herbivores are discussed. Copyright © 2011 Elsevier Ltd. All rights reserved.

Defragged Binary I Ching Genetic Code Chromosomes Compared to Nirenberg’s and Transformed into Rotating 2D Circles and Squares and into a 3D 100% Symmetrical Tetrahedron Coupled to a Functional One to Discern Start From Non-Start Methionines through a Stella Octangula

PubMed Central

Castro-Chavez, Fernando

2012-01-01

Background Three binary representations of the genetic code according to the ancient I Ching of Fu-Xi will be presented, depending on their defragging capabilities by pairing based on three biochemical properties of the nucleic acids: H-bonds, Purine/Pyrimidine rings, and the Keto-enol/Amino-imino tautomerism, yielding the last pair a 32/32 single-strand self-annealed genetic code and I Ching tables. Methods Our working tool is the ancient binary I Ching's resulting genetic code chromosomes defragged by vertical and by horizontal pairing, reverse engineered into non-binaries of 2D rotating 4×4×4 circles and 8×8 squares and into one 3D 100% symmetrical 16×4 tetrahedron coupled to a functional tetrahedron with apical signaling and central hydrophobicity (codon formula: 4[1(1)+1(3)+1(4)+4(2)]; 5:5, 6:6 in man) forming a stella octangula, and compared to Nirenberg's 16×4 codon table (1965) pairing the first two nucleotides of the 64 codons in axis y. Results One horizontal and one vertical defragging had the start Met at the center. Two, both horizontal and vertical pairings produced two pairs of 2×8×4 genetic code chromosomes naturally arranged (M and I), rearranged by semi-introversion of central purines or pyrimidines (M' and I') and by clustering hydrophobic amino acids; their quasi-identity was disrupted by amino acids with odd codons (Met and Tyr pairing to Ile and TGA Stop); in all instances, the 64-grid 90° rotational ability was restored. Conclusions We defragged three I Ching representations of the genetic code while emphasizing Nirenberg's historical finding. The synthetic genetic code chromosomes obtained reflect the protective strategy of enzymes with a similar function, having both humans and mammals a biased G-C dominance of three H-bonds in the third nucleotide of their most used codons per amino acid, as seen in one chromosome of the i, M and M' genetic codes, while a two H-bond A-T dominance was found in their complementary chromosome, as seen in invertebrates and plants. The reverse engineering of chromosome I' into 2D rotating circles and squares was undertaken, yielding a 100% symmetrical 3D geometry which was coupled to a previously obtained genetic code tetrahedron in order to differentiate the start methionine from the methionine that is acting as a codifying non-start codon. PMID:23431415

Specificity of neutral amino acid uptake at the basolateral side of the epithelium in the cat salivary gland in situ.

PubMed

Bustamante, J C; Mann, G E; Yudilevich, D L

1981-01-01

1. Amino acid uptake was measured in resting cat submandibular glands with either a natural blood supply or perfused at constant flow with a Krebs-albumin solution. Following a bolus arterial injection of a 3H-labelled amino acid and D-[14C]mannitol (extracellular reference tracer), the venous effluent was immediately sampled sequentially. The maximal uptake, Umax, from the blood or perfusate was determined from the paired-tracer dilution curves using the expression: uptake % = (1 -- (3H/14C) X 100). 2. In glands with a natural blood supply, Umax values up to 46% were measured for short-chain (serine and alanine) and long-chain (valine, methionine, leucine, isoleucine, 1-amino-cyclopentane cyclopentane carboxylic acid, phenylalanine, tryptophan, tyrosine, histidine and glutamine) neutral amino acids. In contrast, Umax was negligible for amino acids of the imino-glycine group (proline and glycine) and the nonmetabolized amino acids, 2-aminoisobutyric acid (AIB) and methylaminoisobutyric acid (MeAIB). 3. In glands with a natural blood supply addition of an unlabelled amino acid to the tracer injectate reduced Umax for the test acid by up to 80%. The pattern of these interactions suggested the presence of two transport systems for neutral amino acids, one preferring short-chain and the other long-chain amino acids. 4. In glands perfused at constant flow rates with an amino acid-free Krebs-albumin solution high Umax values were measured: L-serine (66%), L-alanine (54%), L-leucine (43%), L-phenylalanine (42%) and L-tyrosine (51%). Only a low uptake was observed for L-proline (8%) and glycine (14%). There was no uptake of methylaminoisobutyric acid which confirms the result obtained in glands with an intact circulation. 5. Saturation of L-phenylalanine influx was observed in perfused glands as the perfusate concentration of unlabelled L-phenylalanine was increased from 0.5 to 20 mmol . 1-1. A Michaelis--Menten analysis based on a single entry system indicated an apparent Km of 6.4 +/- 0.8 mmol . 1-1 and a Vmax of 1719 +/- 94 nmol . min-1g.-1 6. Since the fenestrated capillaries in the salivary gland are readily permeable to the test amino acid and D-mannitol, it is most probable that the amino acid carriers are located in the basolateral side of the epithelium. 7. The use of a paired-tracer dilution technique to measure uptake in a single circulatory passage has enabled a detailed characterization of neutral amino acid transport in the salivary gland and has overcome the limitation of previous studies based on solute transfer from blood to saliva.

Lysozyme oxidation by singlet molecular oxygen: Peptide characterization using [18 O]-labeling oxygen and nLC-MS/MS.

PubMed

Marques, Emerson Finco; Medeiros, Marisa H G; Di Mascio, Paolo

2017-11-01

Singlet molecular oxygen ( 1 O 2 ) is generated in biological systems and reacts with different biomolecules. Proteins are a major target for 1 O 2 , and His, Tyr, Met, Cys, and Trp are oxidized at physiological pH. In the present study, the modification of lysozyme protein by 1 O 2 was investigated using mass spectrometry approaches. The experimental findings showed methionine, histidine, and tryptophan oxidation. The experiments were achieved using [ 18 O]-labeled 1 O 2 released from thermolabile endoperoxides in association with nano-scale liquid chromatography coupled to electrospray ionization mass spectrometry. The structural characterization by nLC-MS/MS of the amino acids in the tryptic peptides of the proteins showed addition of [ 18 O]-labeling atoms in different amino acids. Copyright © 2017 John Wiley & Sons, Ltd.

Structure of a fungal form of aspartate semialdehyde dehydrogenase from Cryptococcus neoformans

PubMed Central

Dahal, Gopal; Viola, Ronald E.

2015-01-01

Aspartate semialdehyde dehydrogenase (ASADH) functions at a critical junction in the aspartate-biosynthetic pathway and represents a valid target for antimicrobial drug design. This enzyme catalyzes the NADPH-dependent reductive dephosphorylation of β-aspartyl phosphate to produce the key intermediate aspartate semialdehyde. Production of this intermediate represents the first committed step in the biosynthesis of the essential amino acids methionine, isoleucine and threonine in fungi, and also the amino acid lysine in bacteria. The structure of a new fungal form of ASADH from Cryptococcus neoformans has been determined to 2.6 Å resolution. The overall structure of CnASADH is similar to those of its bacterial orthologs, but with some critical differences both in biological assembly and in secondary-structural features that can potentially be exploited for the development of species-selective drugs. PMID:26527262

Methyl group turnover on methyl-accepting chemotaxis proteins during chemotaxis by Bacillus subtilis

DOE Office of Scientific and Technical Information (OSTI.GOV)

Thoelke, M.S.; Casper, J.M.; Ordal, G.W.

1990-02-05

The addition of attractant to Bacillus subtilis briefly exposed to radioactive methionine causes an increase of labeling of the methyl-accepting chemotaxis proteins. The addition of attractant to cells radiolabeled for longer times shows no change in the extent of methylation. Therefore, the increase in labeling for the briefly labeled cells is due to an increased turnover of methyl groups caused by attractant. All amino acids gave enhanced turnover. This turnover lasted for a prolonged time, probably spanning the period of smooth swimming caused by the attractant addition. Repellent did not affect the turnover when added alone or simultaneously with attractant.more » Thus, for amino acid attractants, the turnover is probably the excitatory signal, which is seen to extend long into or throughout the adaptation period, not just at the start of it.« less

[Nutritive value of the spirulina algae (Spirulina maxima)].

PubMed

Tejada de Hernández, I; Shimada, A S

1978-06-01

Nine experiments were conducted, five of them in vivo to determine the limiting amino acids and digestibility of spiruline algae for the rat, and four in vitro to determine the digestibility of the product in pepsin and ruminal liquid. None of the amino acids studied (lysine, methionine, histidine) added alone or in combination to 10% protein (either crude or true) diets provided exclusively by spiruline, seems to be limiting although the results could be masked by the low palatability and acceptability of the product by the rats. The apparent digestibility of the algae was 67.4%. For the in vitro tests, the algae were subjected to several physical or chemical treatments, and the digestibility of the resulting product determined by four different techniques. In no case did the tested treatments have any effect on its digestibility.

Nutritional Profile of Phytococktail from Trans-Himalayan Plants

PubMed Central

Dhar, Priyanka; Tayade, Amol B.; Kumar, Jatinder; Chaurasia, Om P.; Srivastava, Ravi B.; Singh, Shashi B.

2013-01-01

We estimated the nutritive value, vitamin content, amino acid composition, fatty acid content, and mineral profile of a phytococktail comprising sea buckthorn (Hippophae rhamnoides), apricot (Prunus armeniaca), and roseroot (Rhodiola imbricata) from trans-Himalaya. The free vitamin forms in the phytococktail were determined by rapid resolution liquid chromatography/tandem mass spectrometry (RRLC-MS/MS). Vitamin E and B-complex vitamins were detected as the principle vitamins. Reversed-phase high performance liquid chromatography (RP-HPLC) with pre-column derivatization was used for identification and quantification of amino acids. Eight essential and eleven non-essential amino acids were quantified, and the content ranged between 76.33 and 9485.67 µg/g. Among the essential amino acids, L-methionine, L-phenylalanine, L-lysine, L-leucine, and L-histidine were found to be the dominant contributors. We also quantified the fatty acids in the phytococktail by using gas chromatography coupled with a flame ionization detector (GC-FID) with fatty acid methyl esters (FAMEs) derivatization. The analysis revealed the presence of 4 major fatty acids contributing to the total lipid content. Palmitic acid was found to be the rich source of saturated fatty acid (SFA) and constituted ∼31% of the total lipid content. Among the unsaturated fatty acids (UFAs), palmitoleic acid (43.47%), oleic acid (20.89%), and linoleic acid (4.31%) were prominent. The mineral profiling was carried out by inductively coupled plasma optical emission spectrometer (ICP-OES), and it was found to contain a number of important dietary mineral elements. The harsh climatic conditions, difficult terrain, and logistic constraints at high altitude regions of Indian trans-Himalayan cold desert lead to the scarcity of fresh fruits and vegetables. Therefore, the source of multiple vitamins, essential amino acids, fatty acids, and dietary minerals from the phytococktail would provide great health benefit in the stressful environment and could be used as a high value nutritional supplement. PMID:24376624

Mung bean proteins and peptides: nutritional, functional and bioactive properties.

PubMed

Yi-Shen, Zhu; Shuai, Sun; FitzGerald, Richard

2018-01-01

To date, no extensive literature review exists regarding potential uses of mung bean proteins and peptides. As mung bean has long been widely used as a food source, early studies evaluated mung bean nutritional value against the Food and Agriculture Organization of the United Nations (FAO)/the World Health Organization (WHO) amino acids dietary recommendations. The comparison demonstrated mung bean to be a good protein source, except for deficiencies in sulphur-containing amino acids, methionine and cysteine. Methionine and cysteine residues have been introduced into the 8S globulin through protein engineering technology. Subsequently, purified mung bean proteins and peptides have facilitated the study of their structural and functional properties. Two main types of extraction methods have been reported for isolation of proteins and peptides from mung bean flours, permitting sequencing of major proteins present in mung bean, including albumins and globulins (notably 8S globulin). However, the sequence for albumin deposited in the UniProt database differs from other sequences reported in the literature. Meanwhile, a limited number of reports have revealed other useful bioactivities for proteins and hydrolysed peptides, including angiotensin-converting enzyme inhibitory activity, anti-fungal activity and trypsin inhibitory activity. Consequently, several mung bean hydrolysed peptides have served as effective food additives to prevent proteolysis during storage. Ultimately, further research will reveal other nutritional, functional and bioactive properties of mung bean for uses in diverse applications.

Mung bean proteins and peptides: nutritional, functional and bioactive properties

PubMed Central

Yi-Shen, Zhu; Shuai, Sun; FitzGerald, Richard

2018-01-01

To date, no extensive literature review exists regarding potential uses of mung bean proteins and peptides. As mung bean has long been widely used as a food source, early studies evaluated mung bean nutritional value against the Food and Agriculture Organization of the United Nations (FAO)/the World Health Organization (WHO) amino acids dietary recommendations. The comparison demonstrated mung bean to be a good protein source, except for deficiencies in sulphur-containing amino acids, methionine and cysteine. Methionine and cysteine residues have been introduced into the 8S globulin through protein engineering technology. Subsequently, purified mung bean proteins and peptides have facilitated the study of their structural and functional properties. Two main types of extraction methods have been reported for isolation of proteins and peptides from mung bean flours, permitting sequencing of major proteins present in mung bean, including albumins and globulins (notably 8S globulin). However, the sequence for albumin deposited in the UniProt database differs from other sequences reported in the literature. Meanwhile, a limited number of reports have revealed other useful bioactivities for proteins and hydrolysed peptides, including angiotensin-converting enzyme inhibitory activity, anti-fungal activity and trypsin inhibitory activity. Consequently, several mung bean hydrolysed peptides have served as effective food additives to prevent proteolysis during storage. Ultimately, further research will reveal other nutritional, functional and bioactive properties of mung bean for uses in diverse applications. PMID:29545737

Case report: Aqueous and Vitreous amino-acid concentrations in a patient with maple syrup urine disease operated on rhegmatogenous retinal detachment.

PubMed

Kanakis, Menelaos G; Michelakakis, Helen; Petrou, Petros; Koutsandrea, Chrysanthi; Georgalas, Ilias

2016-10-03

Maple syrup urine disease (MSUD) is a rare metabolic disorder, affecting the metabolism of branched chain amino-acids (Valine, Leukine, Isoleukine). We present a rare case of rhegmatogenous retinal detachment (RRD) in a MSUD patient. We performed amino acid analysis of aqueous humour, vitreous and serum samples obtained during surgery from a 24 year old female MSUD patient successfully operated on RRD. Serum values for a-amino-butyric acid, valine, isoleucine, leucine, tyrosine, phenylalanine, ornithine and histidine were low, while values for citrulline, methionine and lysine were borderline low, all attributed to the patient's special diet. Serum glutamate was above normal, probably due to the breakdown of glutamine to glutamate. In the aqueous and vitreous the amino acids implicated in MSUD (Valine, Leukine Isoleukine), were within normal range. Glutamate was absent in the vitreous and presented low levels in the aqueous. Glutamate has been reported to play an important role in retinal damage. Elevated glutamate levels have been reported in vitreous specimens from patients subjected to vitrectomy or buckling surgery for RRD. In MSUD, glutamate has been implicated in the pathogenesis of brain damage. Low levels of glutamate have been observed in the cerebellum of experimental MSUD animals, as well as postmortem brain tissue from a child that died of leucine intoxication. The reduction was attributed to the elevation of a-ketoisocaproic which reverses the net direction of nitrogen flow. It could be argued that this could impact on amino acid concentration in aqueous and vitreous fluids. Although no definite conclusions can be drawn by this extremely rare case, the low vitreous and aqueous levels of Glutamate is an interesting finding. Further studies are needed to provide a better insight in the role of amino acids as neurotransmitters in the human eye in health and disease.

Medium-term methionine supplementation increases plasma homocysteine but not ADMA and improves blood pressure control in rats fed a diet rich in protein and adequate in folate and choline.

PubMed

Mariotti, François; Hammiche, Alexia; Blouet, Clémence; Daré, Sophie; Tomé, Daniel; Huneau, Jean François

2006-10-01

Hyperhomocysteinemia (HHcy) is associated with cardiovascular risk, possibly because it increases asymmetric dimethyl-arginine (ADMA), but the general association remains unclear and may vary with nutritional and physiological conditions. We aimed to monitor the effect of methionine supplementation, and subsequent HHcy, on plasma ADMA and hemodynamics in the context of a diet rich in protein and adequate in folic acid and choline. For 6 weeks, rats were fed a 29% protein diet supplemented (M) or not (C) with 8 g/kg L: -methionine. Blood pressure and plasma amino acids, including homocysteine and ADMA, were measured throughout the experiment and additional parameters, including in vivo hemodynamic response to acetylcholine, were measured at week 5-6. As compared to the C diet, the M diet induced a marked HHcy during the first 3 weeks, which lessened at week 5. In contrast, plasma ADMA stayed similar in the C and M diet. Paradoxically, M rats had lower mean and diastolic blood pressure values over the experiment, together with a lower left ventricular mass at week 6, when compared with C rats. No difference was observed between groups regarding vascular reactivity and plasma NOx at week 6. In a context of a diet rich in protein and adequate in methyl donors, rats exhibit a complex adaptation to the medium-term methionine supplementation, with improvement in blood pressure control despite marked HHcy. The lack of increase in plasma ADMA may account for the absence of detrimental effects of HHcy on hemodynamics.

Combined data preprocessing and multivariate statistical analysis characterizes fed-batch culture of mouse hybridoma cells for rational medium design.

PubMed

Selvarasu, Suresh; Kim, Do Yun; Karimi, Iftekhar A; Lee, Dong-Yup

2010-10-01

We present an integrated framework for characterizing fed-batch cultures of mouse hybridoma cells producing monoclonal antibody (mAb). This framework systematically combines data preprocessing, elemental balancing and statistical analysis technique. Initially, specific rates of cell growth, glucose/amino acid consumptions and mAb/metabolite productions were calculated via curve fitting using logistic equations, with subsequent elemental balancing of the preprocessed data indicating the presence of experimental measurement errors. Multivariate statistical analysis was then employed to understand physiological characteristics of the cellular system. The results from principal component analysis (PCA) revealed three major clusters of amino acids with similar trends in their consumption profiles: (i) arginine, threonine and serine, (ii) glycine, tyrosine, phenylalanine, methionine, histidine and asparagine, and (iii) lysine, valine and isoleucine. Further analysis using partial least square (PLS) regression identified key amino acids which were positively or negatively correlated with the cell growth, mAb production and the generation of lactate and ammonia. Based on these results, the optimal concentrations of key amino acids in the feed medium can be inferred, potentially leading to an increase in cell viability and productivity, as well as a decrease in toxic waste production. The study demonstrated how the current methodological framework using multivariate statistical analysis techniques can serve as a potential tool for deriving rational medium design strategies. Copyright © 2010 Elsevier B.V. All rights reserved.

Assessment of cassava toxicity in patients with tropical chronic pancreatitis.

PubMed

Girish, Banavara Narasimhamurthy; Rajesh, Gopalakrishna; Vaidyanathan, Kannan; Balakrishnan, Vallath

2011-01-01

There have been conflicting reports on the role of cassava ingestion in tropical pancreatitis (TCP). In this study we aimed to estimate cyanogens detoxifying enzyme rhodanese, thiocyanate and sulfur containing amino acids in cassava consumer as well as cassava non-consumer TCP patients and healthy controls and compare the same. Eighty-six TCP patients and 90 healthy controls were recruited. Serum rhodanese, thiocyanate, plasma amino acids, urinary inorganic sulfate/creatinine were measured. There was significant reduction in serum rhodanese activity in both cassava consumer- and non-consumer TCP patients as compared to controls but no significant difference between cassava consumer- and non-consumer TCP patients was observed. Serum thiocyanate was significantly lower in cassava consumer TCP patients as compared to cassava consumer controls but not significantly different from cassava non-consumer TCP patients. Plasma methionine, cysteine and urinary inorganic sulfate / creatinine ratio was significantly lower in both cassava consumer and non-consumer TCP patients as compared to controls but were comparable among cassava consumers and non-consumers. Significant reduction in rhodanese activity with concomitant decrease in sulfur containing amino acids and antioxidants such as glutathione suggests that TCP patients are at higher risk of defective detoxification of cyanogens. However there was no difference between cassava consumers and non-consumers. Low levels of sulfur amino acids may contribute to the development of pancreatitis.

Protective and therapeutic effectiveness of taurine in diabetes mellitus: a rationale for antioxidant supplementation.

PubMed

Sirdah, Mahmoud M

2015-01-01

Taurine, 2-amino ethanesulfonic acid, is a conditionally essential β amino acid which is not utilized in protein synthesis. Taurine is one of the most abundant free amino acids in mammals tissues and is one of the three well-known sulfur-containing amino acids; the others are methionine and cysteine which are considered as the precursors for taurine synthesis. Different scientific studies emphasize on the cytoprotective properties of taurine which included antioxidation, antiapoptosis, membrane stabilization, osmoregulation, and neurotransmission. Protective and therapeutic ameliorations of oxidative stress-induced pathologies were also attributed to taurine both in experimental and human models. Data demonstrating the beneficial effectiveness of taurine against type 1 and type 2 diabetes mellitus and their complications are growing and providing a better understanding of the underlying molecular mechanisms. Although the clinical studies are limited compared to the experimental ones, the present updated systematic review of the literature is set up to provide experimental and clinical evidences regarding the effectiveness of taurine in the context of diabetes mellitus and its complications. Gathering these scientific effects of taurine on diabetes mellitus could provide the physicians and specially the endocrinologists with a comprehensive overview on possible trends in the prevention and management of the disease and its complications through antioxidant supplementation. Copyright © 2014 Diabetes India. Published by Elsevier Ltd. All rights reserved.

Effect of dietary supplementation with amino acids on boar sperm quality and fertility.

PubMed

Dong, Hong-Jun; Wu, De; Xu, Sheng-Yu; Li, Qiang; Fang, Zheng-Feng; Che, Lian-Qiang; Wu, Cai-Mei; Xu, Xue-Yu; Lin, Yan

2016-09-01

The aim of this study was to evaluate the effects of dietary supplementation with amino acids on sperm quality and fertility rates after insemination with boar semen. Twelve Yorkshire boars were paired by age and allocated to one of two dietary treatments composed of total lysine levels of 0.64% (T1) and 0.96% (T2), with the lysine: methionine: threonine: tryptophan: valine ratio in the diets set to 100:27:73:19:69 through the addition of synthetic amino acids. Semen was collected twice weekly (phase 1, 1-12 wk); every other day (phase 2, 13-16 wk); twice weekly (phase 3, 17-26 wk); and daily (phase 4, 27-28 wk). Semen was collected from boars during phase 3 and used to inseminate 64 multiparous sows. Our results showed that sperm concentration and total sperm cells were greater in boars in T2 than in boars in T1 in phases 2 and 4 (P<0.05). Sperm motility parameters, morphologically normal sperm, and acrosome integrity in T2 boars were greater than those in T1 boars (P<0.05) during the experiment. Free amino acid concentrations in seminal plasma increased in T2 boars (P<0.05). Furthermore, sows inseminated with semen collected from T2 boars gave birth to more live piglets than those inseminated with semen collected from T1 boars (P=0.04). In conclusion, supplementation of boar diet with amino acids improves sperm quality, and subsequently increases fertilization capacity and the number of live piglets. Copyright © 2016. Published by Elsevier B.V.

A Pepper MSRB2 Gene Confers Drought Tolerance in Rice through the Protection of Chloroplast-Targeted Genes

PubMed Central

Chae, Songhwa; Lee, Tae-Ho; Hwang, Duk-Ju; Oh, Sung-Dug; Park, Jong-Sug; Song, Dae-Geun; Pan, Cheol-Ho; Choi, Doil; Kim, Yul-Ho; Nahm, Baek Hie; Kim, Yeon-Ki

2014-01-01

Background The perturbation of the steady state of reactive oxygen species (ROS) due to biotic and abiotic stresses in a plant could lead to protein denaturation through the modification of amino acid residues, including the oxidation of methionine residues. Methionine sulfoxide reductases (MSRs) catalyze the reduction of methionine sulfoxide back to the methionine residue. To assess the role of this enzyme, we generated transgenic rice using a pepper CaMSRB2 gene under the control of the rice Rab21 (responsive to ABA protein 21) promoter with/without a selection marker, the bar gene. Results A drought resistance test on transgenic plants showed that CaMSRB2 confers drought tolerance to rice, as evidenced by less oxidative stress symptoms and a strengthened PSII quantum yield under stress conditions, and increased survival rate and chlorophyll index after the re-watering. The results from immunoblotting using a methionine sulfoxide antibody and nano-LC-MS/MS spectrometry suggest that porphobilinogen deaminase (PBGD), which is involved in chlorophyll synthesis, is a putative target of CaMSRB2. The oxidized methionine content of PBGD expressed in E. coli increased in the presence of H2O2, and the Met-95 and Met-227 residues of PBGD were reduced by CaMSRB2 in the presence of dithiothreitol (DTT). An expression profiling analysis of the overexpression lines also suggested that photosystems are less severely affected by drought stress. Conclusions Our results indicate that CaMSRB2 might play an important functional role in chloroplasts for conferring drought stress tolerance in rice. PMID:24614245

Deficiency in methionine, tryptophan, isoleucine, or choline induces apoptosis in cultured cells.

PubMed

Yen, Chi-Liang E; Mar, Mei-Heng; Craciunescu, Corneliu N; Edwards, Lloyd J; Zeisel, Steven H

2002-07-01

Cells in culture die by apoptosis when deprived of the essential nutrient choline. We now report that cells (both proliferating PC12 cells and postmitotic neurons isolated from fetal rat brains) undergo apoptosis when deprived of other individual essential nutrients (methionine, tryptophan or isoleucine). In PC12 cells, deficiencies of each nutrient independently led to ceramide accumulation and to caspase activation, both recognized signals of several apoptotic pathways. A similar profile of caspases was activated in PC12 cells deprived of choline, methionine, tryptophan or isoleucine. More than one caspase was involved and these caspases appeared to transmit parallel signals for apoptosis induction because only broad-spectrum caspase inhibitors, but not inhibitors for specific individual caspases inhibited apoptosis in choline- or methionine-deprived cells. The induction of these caspase-dependent apoptosis pathways likely did not involve the same upstream signals. Choline deficiency perturbed choline metabolism but did not affect protein synthesis, whereas amino acid deficiencies inhibited protein synthesis but did not perturb choline metabolism. In addition, a subclone of PC12 cells that was resistant to choline deficiency-induced apoptosis was not resistant to tryptophan deficiency-induced apoptosis. These observations suggest that deficiency of each studied nutrient activates different pathways for signaling apoptosis that ultimately converge on a common execution pathway.

Contribution of dietary amino acids composition to incidence of cardiovascular outcomes: A prospective population-based study.

PubMed

Mirmiran, P; Bahadoran, Z; Ghasemi, A; Azizi, F

2017-07-01

Considering the limited data on the cardiovascular effects of dietary amino acid intakes, we assessed possible association of dietary amino acids with the risk of cardiovascular (CVD) events in a prospective population-based study. Participants without CVD (n = 2369) were recruited from the Tehran Lipid and Glucose Study and were followed for a mean of 6.7 years. Dietary protein and amino acid intakes were assessed at baseline (2006-2008); demographic, lifestyle and biochemical variables were evaluated at baseline and follow-up examination (2012-2014). Multivariate Cox proportional hazard regression models, adjusted for potential confounders, were used to estimate risk of CVD across tertiles of dietary amino acids. Mean total protein intake was 76.9 ± 27.5 g/d, and dietary protein had no significant association with the risk of CVD (HR = 1.23, 95% CI = 0.65-2.31, and HR = 0.52, 95% CI = 0.19-1.41, in the second and third tertiles, respectively). After adjustment of potential confounders, the amino acid pattern with higher load of glycine, cysteine, arginine and tryptophan, was negatively associated with CVD (HR = 0.28, 95% CI = 0.09-0.88, P for trend = 0.08). Higher intake of sulfur-containing amino acids (cysteine and methionine), and potentially cardioprotective amino acids (arginine, cysteine, glutamic acid, glycine, histidine, leucine and tyrosine) corresponded to 73% (HR = 0.27, 95% CI = 0.09-0.86) and 74% (HR = 0.26, 95% CI = 0.09-0.78) decreased risk of CVD events. Higher intake of glutamic acid and proline (% of dietary total protein) increased the risk of CVD (HR = 1.30, 95% CI = 1.03-1.64, and HR = 1.33, 95% CI = 1.10-1.60, respectively). These novel data provide evidence to suggest that amino acid composition of diet may modify the risk of CVD events. Copyright © 2017 The Italian Society of Diabetology, the Italian Society for the Study of Atherosclerosis, the Italian Society of Human Nutrition, and the Department of Clinical Medicine and Surgery, Federico II University. Published by Elsevier B.V. All rights reserved.

Reinventing Cell Penetrating Peptides Using Glycosylated Methionine Sulfonium Ion Sequences.

PubMed

Kramer, Jessica R; Schmidt, Nathan W; Mayle, Kristine M; Kamei, Daniel T; Wong, Gerard C L; Deming, Timothy J

2015-05-27

Cell penetrating peptides (CPPs) are intriguing molecules that have received much attention, both in terms of mechanistic analysis and as transporters for intracellular therapeutic delivery. Most CPPs contain an abundance of cationic charged residues, typically arginine, where the amino acid compositions, rather than specific sequences, tend to determine their ability to enter cells. Hydrophobic residues are often added to cationic sequences to create efficient CPPs, but typically at the penalty of increased cytotoxicity. Here, we examined polypeptides containing glycosylated, cationic derivatives of methionine, where we found these hydrophilic polypeptides to be surprisingly effective as CPPs and to also possess low cytotoxicity. X-ray analysis of how these new polypeptides interact with lipid membranes revealed that the incorporation of sterically demanding hydrophilic cationic groups in polypeptides is an unprecedented new concept for design of potent CPPs.

Cloning and characterization of the metE gene encoding S-adenosylmethionine synthetase from Bacillus subtilis.

PubMed Central

Yocum, R R; Perkins, J B; Howitt, C L; Pero, J

1996-01-01

The metE gene, encoding S-adenosylmethionine synthetase (EC 2.5.1.6) from Bacillus subtilis, was cloned in two steps by normal and inverse PCR. The DNA sequence of the metE gene contains an open reading frame which encodes a 400-amino-acid sequence that is homologous to other known S-adenosylmethionine synthetases. The cloned gene complements the metE1 mutation and integrates at or near the chromosomal site of metE1. Expression of S-adenosylmethionine synthetase is reduced by only a factor of about 2 by exogenous methioinine. Overproduction of S-adenosylmethionine synthetase from a strong constitutive promoter leads to methionine auxotrophy in B. subtilis, suggesting that S-adenosylmethionine is a corepressor of methionine biosynthesis in B. subtilis, as others have already shown for Escherichia coli. PMID:8755891

Cloning and characterization of the metE gene encoding S-adenosylmethionine synthetase from Bacillus subtilis.

PubMed

Yocum, R R; Perkins, J B; Howitt, C L; Pero, J

1996-08-01

The metE gene, encoding S-adenosylmethionine synthetase (EC 2.5.1.6) from Bacillus subtilis, was cloned in two steps by normal and inverse PCR. The DNA sequence of the metE gene contains an open reading frame which encodes a 400-amino-acid sequence that is homologous to other known S-adenosylmethionine synthetases. The cloned gene complements the metE1 mutation and integrates at or near the chromosomal site of metE1. Expression of S-adenosylmethionine synthetase is reduced by only a factor of about 2 by exogenous methioinine. Overproduction of S-adenosylmethionine synthetase from a strong constitutive promoter leads to methionine auxotrophy in B. subtilis, suggesting that S-adenosylmethionine is a corepressor of methionine biosynthesis in B. subtilis, as others have already shown for Escherichia coli.

Reinventing cell penetrating peptides using glycosylated methionine sulfonium ion sequences

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kramer, Jessica R.; Schmidt, Nathan W.; Mayle, Kristine M.

2015-04-15

Cell penetrating peptides (CPPs) are intriguing molecules that have received much attention, both in terms of mechanistic analysis and as transporters for intracellular therapeutic delivery. Most CPPs contain an abundance of cationic charged residues, typically arginine, where the amino acid compositions, rather than specific sequences, tend to determine their ability to enter cells. Hydrophobic residues are often added to cationic sequences to create efficient CPPs, but typically at the penalty of increased cytotoxicity. Here, we examined polypeptides containing glycosylated, cationic derivatives of methionine, where we found these hydrophilic polypeptides to be surprisingly effective as CPPs and to also possess lowmore » cytotoxicity. X-ray analysis of how these new polypeptides interact with lipid membranes revealed that the incorporation of sterically demanding hydrophilic cationic groups in polypeptides is an unprecedented new concept for design of potent CPPs.« less

Kinetic modeling of storage effects on biomarkers related to B vitamin status and one-carbon metabolism.

PubMed

Hustad, Steinar; Eussen, Simone; Midttun, Øivind; Ulvik, Arve; van de Kant, Puck M; Mørkrid, Lars; Gislefoss, Randi; Ueland, Per M

2012-02-01

Biomarkers and metabolites related to B vitamin function and one-carbon metabolism have been studied as predictors of chronic diseases in studies based on samples stored in biobanks. For most biomarkers, stability data are lacking or fragmentary. Degradation and accumulation kinetics of 32 biomarkers were determined at 23 °C in serum and plasma (EDTA, heparin, and citrate) collected from 16 individuals and stored for up to 8 days. In frozen serum (-25 °C), stability was studied cross-sectionally in 650 archival samples stored for up to 29 years. Concentration vs time curves were fitted to monoexponential, biexponential, linear, and nonlinear models. For many biomarkers, stability was highest in EDTA plasma. Storage effects were similar at room temperature and at -25 °C; notable exceptions were methionine, which could be recovered as methionine sulfoxide, and cystathionine, which decreased in frozen samples. Cobalamin, betaine, dimethylglycine, sarcosine, total homocysteine, total cysteine, tryptophan, asymetric and symmetric dimethyl argenine, creatinine, and methylmalonic acid were essentially stable under all conditions. Most B vitamins (folate and vitamins B2 and B6) were unstable; choline increased markedly, and some amino acids also increased, particularly in serum. The kynurenines showed variable stability. For many biomarkers, degradation (folate and flavin mononucleotide) or accumulation (pyridoxal, riboflavin, choline, amino acids) kinetics at room temperature were non-first order. Data on stability and deterioration kinetics for individual biomarkers are required to optimize procedures for handling serum and plasma, and for addressing preanalytical bias in epidemiological and clinical studies.

Animal Proteins as Important Contributors to a Healthy Human Diet.

PubMed

Elmadfa, Ibrahim; Meyer, Alexa L

2017-02-08

Adequate protein intake is critical for health and development. Generally, protein of animal origin is of higher quality for humans owing to its amino acid pattern and good digestibility. When administered in mixtures it can enhance the quality of plant proteins, but its availability is often low in low-income communities, especially in young children, the elderly, and pregnant and lactating women, who have increased requirements and in whom high-quality protein also stimulates (bone) growth and maintenance. Although high protein intake was associated with increased type 2 diabetes mellitus risk, milk and seafood are good sources of branched chain amino acids and taurine, which act beneficially on glucose metabolism and blood pressure. However, high consumption of protein-rich animal food is also associated with adverse health effects and higher risk for noncommunicable diseases, partly related to other components of these foods, like saturated fatty acids and potential carcinogens in processed meat but also the atherogenic methionine metabolite homocysteine. In moderation, however, animal proteins are especially important for health maintenance in vulnerable persons.

Impact of a multicarbohydrase containing α-galactosidase and xylanase on ileal digestible energy, crude protein digestibility, and ileal amino acid digestibility in broiler chickens.

PubMed

Jasek, A; Latham, R E; Mañón, A; Llamas-Moya, S; Adhikari, R; Poureslami, R; Lee, J T

2018-06-08

Exogenous enzymatic supplementation of poultry feeds, including α-galactosidase and xylanase, has been shown to increase metabolically available energy, although little information has been published on the impact on amino acid digestibility. An experiment was conducted to investigate a multicarbohydrase containing α-galactosidase and xylanase on amino acid digestibility, ileal digestible energy (IDE), and CP in male broiler chicks. The experiment was a 2 × 2 (diet × enzyme) factorial arrangement with 15 replicates of 8 male broilers per replicate raised for 21 d in a battery setting. The 2 dietary treatments included a positive control (PC) and a negative control (NC) diet formulated to contain 2.5% less calculated AME and digestible amino acids. Each of these diets was fed with and without enzyme. Broilers were fed a starter diet from 0-14 d (crumble) and a grower from 14-21 d (pellet). Birds were sampled on day 21 to determine ileal amino acid digestibility, IDE, and CP digestibility. Titanium dioxide (TiO2) was used as an indigestible marker for the determination of digestibility coefficients. Total ileal amino acid digestibility was increased (P = 0.008) by 3.80% with the inclusion of enzyme. Methionine and lysine digestibility was improved (P < 0.05) with the inclusion of enzyme by 3.37% and 2.61%, respectively. Enzyme inclusion increased (P = 0.001) cysteine digestibility by 9.3%. Diet-influenced ileal amino acid digestibility with tryptophan, threonine, isoleucine, and valine digestibility being increased (P < 0.05) in the PC when compared to the NC. IDE was decreased (P = 0.037) in broilers fed the NC diet by 100 kcal/kg feed when compared to broilers fed the PC diet. Enzyme inclusion increased (P = 0.047) IDE value by 90 kcal/kg. Crude protein digestibility was not influenced by diet; however, similar improvements in CP digestibility with enzyme inclusion were observed as with energy. These data support the benefits of a multicarbohydrase containing α-galactosidase and xylanase inclusion to improve nutrient and ileal amino acid digestibility across multiple dietary nutrient profiles.

Acid lipase inhibitor in chicken plasma identified as apolipoprotein A-I.

PubMed

Fujii, M; Higuchi, T; Mukai, S; Yonekura, M; Yano, T; Kawaguchi, H; Nonaka, K; Fukunaga, T; Sugimoto, Y; Yamada, S

1996-10-01

We have reported a inhibitor of acid lipases in liver lysosomes and erythrocytes from chickens [M. Fujii et al., Int. J. Biochem., 22, 895-898 (1990)]. In this paper, the properties of the inhibitor were described in comparison with those of apo A-I of chicken. The purified inhibitor migrated with the same mobility on SDS-PAGE as apo A-I, and had a molecular weight of 27,000. The peptide map from the lipase inhibitor was similar to that of apo A-I. Antibodies to the acid lipase inhibitor also reacted with apo A-I. Apo A-I inhibited the acid lipase activities of liver lysosomes and erythrocytes from chickens as strongly as the lipase inhibitor. The N-terminal amino acid sequence of lipase inhibitor was identical to that of apo A-I as far as residue 20. The amino acid sequence of peptides obtained from the inhibitor by cleavage with CNBr corresponded to internal sequence of apo A-I, and so the CNBr-peptides were derived by cleavage after the methionine residues in apo A-I. The findings showed that the inhibitor of the acid lipases in liver lysosomes and erythrocytes from chickens was identical to apo A-I.

Sensorially important aldehyde production from amino acids in model wine systems: impact of ascorbic acid, erythorbic acid, glutathione and sulphur dioxide.

PubMed

Grant-Preece, Paris; Fang, Hongjuan; Schmidtke, Leigh M; Clark, Andrew C

2013-11-01

The efficiency of different white wine antioxidant systems in preventing aldehyde production from amino acids by oxidative processes is not well understood. The aim of this study was to assess the efficiency of sulphur dioxide alone and in combination with either glutathione, ascorbic acid or its stereoisomer erythorbic acid, in preventing formation of the sensorially important compounds methional and phenylacetaldehyde from methionine and phenylalanine in model white wine. UHPLC, GC-MS/MS, LC-MS/MS, flow injection analysis and luminescence sensors determined both compositional changes during storage, and sulphur dioxide-aldehyde apparent equilibrium constants. Depending on temperature (25 or 45°C) or extent of oxygen supply, sulphur dioxide was equally or more efficient in impeding the production of methional compared to the other antioxidant systems. For phenylacetaldehyde, erythorbic acid or glutathione with sulphur dioxide provided improved inhibition compared to sulphur dioxide alone, in conditions of limited oxygen consumption. The results also demonstrate the extent to which sulphur dioxide addition can lower the free aldehyde concentrations to below their aroma thresholds. Copyright © 2013 Elsevier Ltd. All rights reserved.

Development and cytotoxicity of Schiff base derivative as a fluorescence probe for the detection of L-Arginine

NASA Astrophysics Data System (ADS)

Shang, Xuefang; Li, Jie; Guo, Kerong; Ti, Tongyu; Wang, Tianyun; Zhang, Jinlian

2017-04-01

Inspired from biological counter parts, chemical modification of Schiff base derivatives with function groups may provide a highly efficient method to detect amino acids. Therefore, a fluorescent probe involving Schiff base and hydroxyl group has been designed and prepared, which showed high response and specificity for Arginine (Arg) among normal eighteen standard kinds of amino acids (Alanine, Valine, Leucine, Isoleucine, Methionine, Asparticacid, Glutamicacid, Arginine, Glycine, Serine, Threonine, Asparagine, Phenylalanine, Histidine, Tryptophan, Proline, Lysine, Glutamine, Tyrosine and Cysteine). Furthermore, theoretical investigation further illustrated the possible binding mode in the host-guest interaction and the roles of molecular frontier orbitals in molecular interplay. In addition, the synthesized fluorescent probe exhibited high binding ability for Arg and low cytotoxicity to MCF-7 cells over a concentration range of 0-200 μg mL-1 which can be also used as a biosensor for the Arg detection in vivo.

Some Nutritional Characteristics of a Naturally Occurring Alga (Microcystis sp.) in a Guatemalan Lake

PubMed Central

de la Fuente, Gabriel; Flores, Antonio; Molina, Mario R.; Almengor, Leticia; Bressani, Ricardo

1977-01-01

The nutritional characteristics of an alga (Microcystis sp.) that occurs naturally in a Guatemalan lake were determined. The sun-dried material proved to have a high protein content (55.6%) and to be a possible good source of calcium and phosphorus (1, 169.1 and 633.4 mg/100 mg, respectively). Amino acid analysis showed that total sulfur amino acids were the most deficient ones, giving a protein score of 42 to the material. The in vitro protein digestibility of the material was 69.5%. Biological trials demonstrated that when the material was offered as the only protein source, very low consumption and a high mortality rate were obtained whether or not the diet was supplemented with 0.4% dl-methionine. However, when the material supplied 25% of the total protein of a corn-algae diet, the protein quality of the cereal was significantly improved (P < 0.05). PMID:16345191

The primary structure of L37--a rat ribosomal protein with a zinc finger-like motif.

PubMed

Chan, Y L; Paz, V; Olvera, J; Wool, I G

1993-04-30

The amino acid sequence of the rat 60S ribosomal subunit protein L37 was deduced from the sequence of nucleotides in a recombinant cDNA. Ribosomal protein L37 has 96 amino acids, the NH2-terminal methionine is removed after translation of the mRNA, and has a molecular weight of 10,939. Ribosomal protein L37 has a single zinc finger-like motif of the C2-C2 type. Hybridization of the cDNA to digests of nuclear DNA suggests that there are 13 or 14 copies of the L37 gene. The mRNA for the protein is about 500 nucleotides in length. Rat L37 is related to Saccharomyces cerevisiae ribosomal protein YL35 and to Caenorhabditis elegans L37. We have identified in the data base a DNA sequence that encodes the chicken homolog of rat L37.

Postnatal development of plasma amino acids in hyperphagic rats.

PubMed

Salvadó, M J; Segués, T; Arola, L

1991-01-01

The effect of feeding a highly palatable high-energy cafeteria diet on individual amino acid levels in plasma during postnatal development of the rat has been evaluated and compared to chow-fed controls. The cafeteria diet selected by the rats was hypercaloric and hyperlipidic, with practically the same amount of carbohydrate as the control diet, and slightly hyperproteic. In response to cafeteria feeding, significant decreases were observed in plasma serine and cysteine along the period studied. Significant changes with age during the growth period were shown by cafeteria-fed animals, which were not observed in control rats. Citrulline levels were lower on days 10 and 14 in cafeteria pups than in chow pups. Methionine was highest on day 30. Threonine was also higher at days 20 and 30, as was valine but with a nadir at day 10. Lysine showed maximal values on days 14 and 30.

Chemical and sensory evaluation of dark chocolate with addition of quinoa (Chenopodium quinoa Willd.).

PubMed

Schumacher, Andrea B; Brandelli, Adriano; Macedo, Fernanda C; Pieta, Luiza; Klug, Tâmmila V; de Jong, Erna V

2010-03-01

Quinoa (Chenopodium quinoa Willd) is a good source of vitamin E containing high quality protein. A dark chocolate with the addition of 12, 16 or 20% quinoa was developed. The protein concentration of the products increased as the percentage of quinoa increased. The product containing 20% quinoa showed only 9% increase in vitamin E, while the quantity of polyphenols decreased from 23.5 to 18 μmol pirocatechin/g. The amount of essential amino acids was improved in samples containing quinoa. Cysteine, tyrosine and methionine increased by 104, 72, 70%, respectively in chocolate containing 20% quinoa. The amino acid pattern was as per WHO standards, which was adequate to human needs. The chocolate with quinoa was approved by 92% of the sensory panel. All the samples showed an index of acceptance above 70%. Quinoa could be used at the levels evaluated in this study adding its potential health benefit to the dark chocolate.

[Molecular and structural-biological analysis of Nicotiana plumbaginifolia mutants for identification of the site of beta-tubulins interaction with dinitroanilines and phosphorotioamidates].

PubMed

Emets, A I; Baiard, U V; Nyporko, A Iu; Swire-Clark, G A; Blium, Ia B

2009-01-01

The identification of point mutation locations on beta-tubulin molecules of amiprophosmethyl- and trifluralin-resistant Nicotiana plumbaginifolia lines have described in the work. It was shown that in the first case this mutation is connected with the substitution ofserine residue on proline in position 248; in the second case--with the substitution of phenilalanine on serine in position 317 of beta-tubulin amino acid sequence. Three-dimensional models of beta-tubulin molecule from Chlamydomonas with well-known location of mutations conferring dinitroaniline- and phosphorotioamidate resistance (substitution of lysine residue to methionine on position 350), and beta-tubulin from Nicotiana plumbaginifolia have been reconstructed. On the basis of analysis of site of interaction with dinitroanilines and phosphorotioamides on Chlamydomonas beta-tubulin molecule it was concluded that the revealed mutations on Nicotiana plumbaginifolia beta-tubulin affect amino acid residues participating in formation of this site.

Nutritional Properties Assessment of Endogenous and Improved Varieties of Maize (Zea mays L.) Grown in Southern Benin.

PubMed

Josiane, Semassa Adjobignon; Bienvenu, Anihouvi Victor; Wilfried, Padonou Segla; Adolphe, Adjanohoun; Djima, Aly; Joachin, Gbenou; Lamine, Baba-Moussa

2017-01-01

A wide range of maize varieties is used in Benin but information on the nutritional characteristics of these varieties are not well known. This study aims to assess the nutritional composition of maize varieties in use in the southern region of Benin with the purpose of providing consumers accurate information for better choice. Moisture, ash, protein, fiber and fat contents were determined according to Association of Official Analytical Chemists and American Association of Cereal Chemists methods. Sugar and organic acids were assessed using High Performance Liquid Chromatography methods and amino acids profile was established according to Rosen method using glutamic acid. The maize varieties were classified into 5 clusters according to their macro nutrients composition and 4 clusters based on their sugar and organic acids contents. Varieties of group 5 were very rich in protein (14.34 g/100 g), while the highest fat content (7.22 g/100 g) was observed for group 2 varieties. The highest carbohydrate contents obtained were 80.64 g/100 g, 80.11 g/100 g and 79.15 g/100 g for groups 1, 4 and 5 varieties respectively. Moreover the dendrogram gave four homogeneous clusters according to sugars and organic acids composition. Varieties of groups 2, 3 and 4 had almost the same fructose contents ranging between 0.04 and 0.06%; varieties of group 1 contained the highest contents of raffinose, sucrose and glucose; those of group 2 were very rich in propionate and fructose. It is concluded that some of maize varieties investigated contained high level of protein. Furthermore glutamic acid was the predominant amino acid while the least amino acid was methionine. Those varieties, owing to their protein and amino acids contents could have many benefits by providing vital constituents to the body.

In Vivo Photo-Cross-Linking to Study T3S Interactions Demonstrated Using the Yersinia pestis T3S System.

PubMed

Henderson, Thomas A; Nilles, Matthew L

2017-01-01

Cross-linking of proteins is effective in determining protein-protein interactions. The use of photo-cross-linkers was developed to study protein interactions in several manners. One method involved the incorporation of photo-activatable cross-linking groups into chemically synthesized peptides. A second approach relies on incorporation of photo-activatable cross-linking groups into proteins using tRNAs with chemically bound photo-activatable amino acids with suppressor tRNAs translational systems to incorporate the tags into specific sites. A third system was made possible by the development of photoreactive amino acids that use the normal cellular tRNAs and aminoacyl tRNA synthetases. In this method, the third system is used to demonstrate its utility for the study of T3S system interactions. This method describes how two photo-activatable amino acids, photo-methionine and photo-leucine, that use the normal cellular machinery are incorporated into Yersinia pestis and used to study interactions in the T3S system. To demonstrate the system, the method was used to cross-link the T3S regulatory proteins LcrG and LcrV.

The complete nucleotide sequence of RNA beta from the type strain of barley stripe mosaic virus.

PubMed Central

Gustafson, G; Armour, S L

1986-01-01

The complete nucleotide sequence of RNA beta from the type strain of barley stripe mosaic virus (BSMV) has been determined. The sequence is 3289 nucleotides in length and contains four open reading frames (ORFs) which code for proteins of Mr 22,147 (ORF1), Mr 58,098 (ORF2), Mr 17,378 (ORF3), and Mr 14,119 (ORF4). The predicted N-terminal amino acid sequence of the polypeptide encoded by the ORF nearest the 5'-end of the RNA (ORF1) is identical (after the initiator methionine) to the published N-terminal amino acid sequence of BSMV coat protein for 29 of the first 30 amino acids. ORF2 occupies the central portion of the coding region of RNA beta and ORF3 is located at the 3'-end. The ORF4 sequence overlaps the 3'-region of ORF2 and the 5'-region of ORF3 and differs in codon usage from the other three RNA beta ORFs. The coding region of RNA beta is followed by a poly(A) tract and a 238 nucleotide tRNA-like structure which are common to all three BSMV genomic RNAs. Images PMID:3754962

Recombinant Polycistronic Structure of Hydantoinase Process Genes in Escherichia coli for the Production of Optically Pure d-Amino Acids▿ †

PubMed Central

Martínez-Gómez, Ana Isabel; Martínez-Rodríguez, Sergio; Clemente-Jiménez, Josefa María; Pozo-Dengra, Joaquín; Rodríguez-Vico, Felipe; Las Heras-Vázquez, Francisco Javier

2007-01-01

Two recombinant reaction systems for the production of optically pure d-amino acids from different d,l-5-monosubstituted hydantoins were constructed. Each system contained three enzymes, two of which were d-hydantoinase and d-carbamoylase from Agrobacterium tumefaciens BQL9. The third enzyme was hydantoin racemase 1 for the first system and hydantoin racemase 2 for the second system, both from A. tumefaciens C58. Each system was formed by using a recombinant Escherichia coli strain with one plasmid harboring three genes coexpressed with one promoter in a polycistronic structure. The d-carbamoylase gene was cloned closest to the promoter in order to obtain the highest level of synthesis of the enzyme, thus avoiding intermediate accumulation, which decreases the reaction rate. Both systems were able to produce 100% conversion and 100% optically pure d-methionine, d-leucine, d-norleucine, d-norvaline, d-aminobutyric acid, d-valine, d-phenylalanine, d-tyrosine, and d-tryptophan from the corresponding hydantoin racemic mixture. For the production of almost all d-amino acids studied in this work, system 1 hydrolyzed the 5-monosubstituted hydantoins faster than system 2. PMID:17220246

Cloning and characterization of cDNAs encoding human gastrin-releasing peptide.

PubMed Central

Spindel, E R; Chin, W W; Price, J; Rees, L H; Besser, G M; Habener, J F

1984-01-01

We have prepared and cloned cDNAs derived from poly(A)+ RNA from a human pulmonary carcinoid tumor rich in immunoreactivity to gastrin-releasing peptide, a peptide closely related in structure to amphibian bombesin. Mixtures of synthetic oligodeoxyribonucleotides corresponding to amphibian bombesin were used as hybridization probes to screen a cDNA library prepared from the tumor RNA. Sequencing of the recombinant plasmids shows that human gastrin-releasing peptide (hGRP) mRNA encodes a precursor of 148 amino acids containing a typical signal sequence, hGRP consisting of 27 or 28 amino acids, and a carboxyl-terminal extension peptide. hGRP is flanked at its carboxyl terminus by two basic amino acids, following a glycine used for amidation of the carboxyl-terminal methionine. RNA blot analyses of tumor RNA show a major mRNA of 900 bases and a minor mRNA of 850 bases. Blot hybridization analyses using human genomic DNA are consistent with a single hGRP-encoding gene. The presence of two mRNAs encoding the hGRP precursor protein in the face of a single hGRP gene raises the possibility of alternative processing of the single RNA transcript. Images PMID:6207529

A 100-Year Review: Protein and amino acid nutrition in dairy cows.

PubMed

Schwab, Charles G; Broderick, Glen A

2017-12-01

Considerable progress has been made in understanding the protein and amino acid (AA) nutrition of dairy cows. The chemistry of feed crude protein (CP) appears to be well understood, as is the mechanism of ruminal protein degradation by rumen bacteria and protozoa. It has been shown that ammonia released from AA degradation in the rumen is used for bacterial protein formation and that urea can be a useful N supplement when lower protein diets are fed. It is now well documented that adequate rumen ammonia levels must be maintained for maximal synthesis of microbial protein and that a deficiency of rumen-degradable protein can decrease microbial protein synthesis, fiber digestibility, and feed intake. Rumen-synthesized microbial protein accounts for most of the CP flowing to the small intestine and is considered a high-quality protein for dairy cows because of apparent high digestibility and good AA composition. Much attention has been given to evaluating different methods to quantify ruminal protein degradation and escape and for measuring ruminal outflows of microbial protein and rumen-undegraded feed protein. The methods and accompanying results are used to determine the nutritional value of protein supplements and to develop nutritional models and evaluate their predictive ability. Lysine, methionine, and histidine have been identified most often as the most-limiting amino acids, with rumen-protected forms of lysine and methionine available for ration supplementation. Guidelines for protein feeding have evolved from simple feeding standards for dietary CP to more complex nutrition models that are designed to predict supplies and requirements for rumen ammonia and peptides and intestinally absorbable AA. The industry awaits more robust and mechanistic models for predicting supplies and requirements of rumen-available N and absorbed AA. Such models will be useful in allowing for feeding lower protein diets and increased efficiency of microbial protein synthesis. Copyright © 2017 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Homocysteine remethylation in young broilers fed varying levels of methionine, choline, and betaine.

PubMed

Pillai, P B; Fanatico, A C; Beers, K W; Blair, M E; Emmert, J L

2006-01-01

Methionine is critical in amino acid nutrition for chickens, yet details of the flux of Met metabolites in the avian system are lacking. This study explored the interactions among dietary choline (CHO), betaine (BET), and sulfur amino acid levels on growth and hepatic homocysteine (HCY) remethylation. Graded levels (0, 0.07, 0.11, and 0.24%) of DL-Met were added to diets adequate in CHO and deficient in sulfur amino acids (0.26% digestible Met, 0.26% digestible Cys). Each Met level was tested alone or with the addition of CHO (0.25%) or BET (0.28%). Broilers were reared from 8 to 22 d in raised wire floor battery cages, and the 12 dietary treatments were fed to 3 replicate pens containing 5 birds per pen. Weight gain and feed efficiency were maximized (P < 0.05) with addition of 0.11% supplemental Met, whereas feed intake was maximized (P < 0.05) with addition of 0.07% supplemental Met. Overall, growth parameters were not affected (P > 0.05) by CHO or BET addition. Hepatic tissue primed by the different dietary treatments was subjected to a newly developed stable isotope methodology and HPLC-mass spectrometry to quantify the impact of diet on HCY remethylation. Dietary Met level did not (P > 0.05) affect HCY remethylation, but remethylation through the Met synthase pathway was increased (P < 0.05) by addition of CHO or BET to diets containing deficient or excess levels of Met. Minimal changes in hepatic HCY remethylation through the betaine-homocysteine methyltransferase pathway occurred in response to dietary changes; therefore, data failed to support previous suggestions that BHMT might have a regulatory role when diets containing deficient or excess Met levels are fed. In contrast to previous suppositions based on enzyme activity, under most dietary conditions, the quantity of HCY remethylated by Met synthase appeared to exceed that remethylated by the alternate betaine-homocysteine methyltransferase pathway.

Influence of cysteine doping on photoluminescence intensity from semiconducting single-walled carbon nanotubes

NASA Astrophysics Data System (ADS)

Kurnosov, N. V.; Leontiev, V. S.; Linnik, A. S.; Karachevtsev, V. A.

2015-03-01

Photoluminescence (PL) from semiconducting single-walled carbon nanotubes can be applied for detection of cysteine. It is shown that cysteine doping (from 10-8 to 10-3 M) into aqueous suspension of nanotubes with adsorbed DNA leads to increase of PL intensity. The PL intensity was enhanced by 27% at 10-3 M cysteine concentration in suspension. Most likely, the PL intensity increases due to the passivation of p-defects on the nanotube by the cysteine containing reactive thiol group. The effect of doping with other amino acids without this group (methionine, serine, aspartic acid, lysine, proline) on the PL intensity is essentially weaker.

Characterization of taste-active compounds of various cherry wines and their correlation with sensory attributes.

PubMed

Niu, Yunwei; Zhang, Xiaoming; Xiao, Zuobing; Song, Shiqing; Jia, Chengsheng; Yu, Haiyan; Fang, Lingling; Xu, Chunhua

2012-08-01

Five cherry wines exhibiting marked differences in taste and mouthfeel were selected for the study. The taste and mouthfeel of cherry wines were described by four sensory terms as sour, sweet, bitter and astringent. Eight organic acids, seventeen amino acids, three sugars and tannic acid were determined by high performance liquid chromatography (HPLC). Five phenolic acids were determined by ultra performance liquid chromatography coupled with mass spectrometry (UPLC-MS). The relationship between these taste-active compounds, wine samples and sensory attributes was modeled by partial least squares regression (PLSR). The regression analysis indicated tartaric acid, methionine, proline, sucrose, glucose, fructose, asparagines, serine, glycine, threonine, phenylalanine, leucine, gallic acid, chlorogenic acid, vanillic acid, arginine and tannic acid made a great contribution to the characteristic taste or mouthfeel of cherry wines. Copyright © 2012 Elsevier B.V. All rights reserved.

Exploration of Sea Cucumbers Stichopus hermanii from Karimunjawa Islands as Production of Marine Biological Resources

NASA Astrophysics Data System (ADS)

Pringgenies, Delianis; Rudiyanti, Siti; Yudiati, Ervia

2018-02-01

This research aim was to study the potential of Stichopus hermanii to determine the amino acid, chondroitin, and glucosamine contents, to discover its antibacterial and anti-cancer agent. The samples were rinsed prior to separation, with only the corpus being used in the study. Sea cucumber extract was then processed using HPLC to trace contents of amino acid, chondroitin, and glucosamine contents. The samples were then put into test against several strains of pathogenic bacteria by means of diffusion for any biological activity. The anti-cancer test was performed by human ovarian cancer cell line (KOC7C) method. The study showed that the extract of Stichopus hermanii has the potency to inhibit the growth of active ovarian cancer cells. The qualitative test of the sea cucumber extract showed that it is capable of suppressing the growth of several strains of pathogenic bacteria identified as Staphylococcus aureus, Escherichia coli, Vibrio voinivica, and Pseudomonas sp. HPLC results showed that the extract contained amino acid (mg/100g), the highest being Collagen (11200), followed by Glycine (3760), Glutamic Acid (3700), Aspartic Acid (2540), Alanine (2140), Proline (2050), Arginine (2050), Tyrosine (1430), Threonine (1270), Leucine (1170), Valine (1050), Serine (971), Isoleucine (816), Phenylalanine (713), Lysine (639), Methionine (383), Cystine (263) and Histidine (208). The extract also contained Chondroitin Sulfate (4200) and Glucosamine Hydrochloride (<5.00). In conclusion, the study found that the extract of Stichopus hermanii has potential as anti-cancer, particularly against ovarian cancer, with the highest content being Collagen within amino acids, as well as chondroitin and glucosamine.

Manufacture and characterization of kefir made from cow and buffalo milk, using kefir grain and starter culture.

PubMed

Gul, O; Mortas, M; Atalar, I; Dervisoglu, M; Kahyaoglu, T

2015-03-01

The microbiological and chemical characteristics as well as organic and amino acid profiles of kefir samples made from cow and buffalo milks fermented by kefir grains and starter culture were investigated during storage for 21 d at 4°C. After incubation, lactic, acetic, and citric acid concentrations showed a difference among the samples due to milk type and production methods. Storage time had little effect on the organic acid values of kefir samples. As compared with cow milk kefir, buffalo milk kefir had higher numbers of microorganisms, except lactobacilli, at the end of storage. Whereas pH and titratable acidity exhibited similar changes during storage in all kefir samples, ethanol levels were significantly increased in buffalo milk kefir samples. Glutamic acid was the major amino acid at all sampling times for all samples. Tyrosine, serine, histidine, alanine, methionine, and lysine concentrations were determined to be different in all samples depending on milk type. In general, due to the higher microbial population (especially yeast), kefir made from buffalo milk may be preferred. Copyright © 2015 American Dairy Science Association. Published by Elsevier Inc. All rights reserved.

Histone H1 heterogeneity in the midge, Chironomus thummi. Structural comparison of the H1 variants in an organism where their intrachromosomal localization is possible.

PubMed

Hoyer-Fender, S; Grossbach, U

1988-09-01

1. Seven subfractions of histone H1 have been isolated and purified from larvae of Chironomus thummi (Diptera). They have been denominated I-1, II-1, II-2, II-3, III-1, III-2, and III-3, according to the order of migration in two steps of preparative electrophoresis. 2. The amino acid compositions are similar to those of other H1 histones. Subfractions I-1 and II-1 were found to contain one methionine and two tyrosine residues, II-2 contained two methionine and three tyrosine residues, and III-1 one methionine and three tyrosine residues. The other subfractions contained one or two methionine and two or three tyrosine residues. For subfractions I-1 and II-1 a chain length of about 252 amino acids was estimated. 3. Peptide pattern analyses after chemical cleavage at the methionine and tyrosine residues, and enzymatic cleavage with thrombin and chymotrypsin, respectively, showed that all subfractions have different individual primary structures. A comparison of peptide sizes and of the positions in the peptide patterns of epitopes recognized by monoclonal antibodies was made to check whether some of the subfractions could arise by proteolytic degradation of others. This possibility can be excluded for five of the subfractions and is very improbable for the two others. Treatment of C. thummi H1 with alkaline phosphatase did not change the pattern of subfractions, while the phosphorylated subfraction of histone H2A disappeared after this treatment. Most and very probably all subfractions are thus H1 sequence variants. 4. Inbred strains and individual larvae of C. thummi were found to comprise all seven variants. The H1 heterogeneity can therefore not be due to allelic polymorphism. Salivary gland nuclei were found to contain variant I-1 and at least some of the other variants. 5. H1 from Drosophila melanogaster and from calf thymus were used as reference molecules in all cleavage experiments and yielded the peptide patterns expected from the sequence. The comparison discriminates the group of C. thummi H1 histones clearly from Drosophila and calf thymus H1. Limited trypsin digestion yielded a protected peptide of uniform size in six of the seven variants which was considerably smaller than the protected central domain of calf thymus H1. 6. Two other species of Chironomidae, C. pallidivittatus and Glyptotendipes barbipes were found to contain five and three H1 subfractions, respectively.(ABSTRACT TRUNCATED AT 400 WORDS)

Effect of selected fungi on the reduction of gossypol levels and nutritional value during solid substrate fermentation of cottonseed meal*

PubMed Central

Zhang, Wen-ju; Xu, Zi-rong; Sun, Jian-yi; Yang, Xia

2006-01-01

The objective of this work was to investigate the effect of six individual strains of fungi on the reduction of gossypol levels and nutritional value during solid substrate fermentation of cottonseed meal (CSM). Six groups of disinfected CSM substrate were incubated for 48 h after inoculation with either of the fungi C. capsuligena ZD-1, C. tropicalis ZD-3, S. cerevisae ZD-5, A. terricola ZD-6, A. oryzae ZD-7, or A. niger ZD-8. One not inoculated group (substrate) was used as a control. Levels of initial and final free gossypol (FG), crude protein (CP), amino acids (AA) and in vitro digestibility were assayed. The experiment was done in triplicate. The experimental results indicated that microbial fermentation could greatly decrease (P<0.05) FG levels in CSM. The detoxification efficiency differed between the species of microorganisms applied. From the perspective of reducing CSM potential toxicity, C. tropicalis ZD-3 was most successful followed by S. cerevisae ZD-5 and A. niger ZD-8. They could reduce FG levels of CSM to 29.8, 63.07 and 81.50 mg/kg based on DM (dry matter), respectively, and their detoxification rates were 94.57%, 88.51% and 85.16%, respectively. If crude protein, amino acids content and their in vitro digestibility were also taken into account, A. niger ZD-8 may be the best choice. The CP content of CSM substrate fermented by C. tropicalis ZD-3 and A. niger ZD-8 were improved by 10.76% and 22.24%; the TAA (total amino acids) contents were increased by 7.06% and 11.46%, and the EAA (essential amino acids) were raised by 7.77% and 12.64%, respectively. Especially, the levels of methionine, lysine and threonine were improved greatly (P<0.05). The in vitro CP digestibility of CSM fermented by C. tropicalis ZD-3 and A. niger ZD-8 was improved by 13.42% and 18.22%, the TAA were increased by 17.75% and 22.88%, and the EAA by 16.61% and 21.01%, respectively. In addition, the in vitro digestibility of methionine, lysine and threonine was also improved greatly (P<0.05). PMID:16909468

Hypochlorous and peracetic acid induced oxidation of dairy proteins.

PubMed

Kerkaert, Barbara; Mestdagh, Frédéric; Cucu, Tatiana; Aedo, Philip Roger; Ling, Shen Yan; De Meulenaer, Bruno

2011-02-09

Hypochlorous and peracetic acids, both known disinfectants in the food industry, were compared for their oxidative capacity toward dairy proteins. Whey proteins and caseins were oxidized under well controlled conditions at pH 8 as a function of the sanitizing concentration. Different markers for protein oxidation were monitored. The results established that the protein carbonyl content was a rather unspecific marker for protein oxidation, which did not allow one to differentiate the oxidant used especially at the lower concentrations. Cysteine, tryptophan, and methionine were proven to be the most vulnerable amino acids for degradation upon hypochlorous and peracetic acid treatment, while tyrosine was only prone to degradation in the presence of hypochlorous acid. Hypochlorous acid induced oxidation gave rise to protein aggregation, while during peracetic acid induced oxidation, no high molecular weight aggregates were observed. Protein aggregation upon hypochlorous acid oxidation could primarily be linked to tryptophan and tyrosine degradation.

Prevention by Methionine of Enhancement of Hepatocarcinogenesis by Coadministration of a Choline‐deficient L‐Amino Acid‐defined Diet and Ethionine in Rats

PubMed Central

Tsujiuchi, Toshifumi; Kobayashi, Eisaku; Nakae, Dai; Mizumoto, Yasushi; Andoh, Nobuaki; Kitada, Hiromichi; Ohashi, Kazuo; Fukuda, Tomokazu; Kido, Akira; Tsutsumi, Masahiro; Denda, Ayumi

1995-01-01

The effects of methionine on hepatocarcinogenesis induced by Coadministration of a choline‐deflcient L‐amino acid‐defined (CDAA) diet and ethionine were examined. F344 male rats were divided into 4 experimental groups. Groups 1 and 2 received the CDAA diet and a choline‐supplemented L‐amino acid‐defined (CSAA) diet, respectively. Group 3 received the CDAA diet containing 0.05% ethionine, and group 4 the CDAA diet containing 0.05% ethionine and 0.47% methionine. Animals were killed after 12 weeks of treatment. Histologically, the CDAA diet induced intracellular fat accumulation and foci. In contrast, ethionine caused not only foci, but also hyperplastic nodules, cholangiofibrosis and the proliferation of oval cells without such fat accumulation. Methionine abolished the development of all of the liver lesions induced by Coadministration of the CDAA diet and ethionine. To investigate the effects of methionine on induction of c‐myc and c‐Ha‐ras expression, as well as generation of 8‐hydroxyguanine (8‐OHGua) and 2‐thiobarbituric acid‐reacting substances (TBARS), by Coadministration of the CDAA diet and ethionine, subgroups of 3 to 5 animals were killed at 2, 4, 8 or 11 days after the beginning of the experiment. Coadministration of the CDAA diet and ethionine markedly enhanced the level of expression of c‐myc and c‐Ha‐ras, 8‐OHGua formation and TBARS generation as compared with the CDAA or CSAA diet within 11 days, and methionine blocked these actions. These results indicate that addition of methionine prevents the induction of c‐myc and c‐Ha‐ras expression, 8‐OHGua formation and TBARS generation, as well as hepatocellular lesions, by Coadministration of the CDAA diet and ethionine in rats, and suggest a possible involvement of oxidative stress and gene expression in hepatocarcinogenesis by these agents. PMID:8636001

Docking of oxalyl aryl amino benzoic acid derivatives into PTP1B

PubMed Central

Verma, Neelam; Mittal, Minakshi; Verma, Raman kumar

2008-01-01

Protein Tyrosine Phosphatases (PTPs) that function as negative regulators of the insulin signaling cascade have been identified as novel targets for the therapeutic enhancement of insulin action in insulin resistant disease states. Reducing Protein Tyrosine Phosphatase1B (PTP1B) abundance not only enhances insulin sensitivity and improves glucose metabolism but also protects against obesity induced by high fat feeding. PTP1B inhibitors such as Formylchromone derivatives, 1, 2-Naphthoquinone derivatives and Oxalyl aryl amino benzoic derivatives may eventually find an important clinical role as insulin sensitizers in the management of Type-II Diabetes and metabolic syndrome. We have carried out docking of modified oxalyl aryl amino benzoic acid derivatives into three dimensional structure of PTP1B using BioMed CAChe 6.1. These compounds exhibit good selectivity for PTP1B over most of phosphatases in selectivity panel such as SHP-2, LAR, CD45 and TCPTP found in literature. This series of compounds identified the amino acid residues such as Gly220 and Arg221 are important for achieving specificity via H-bonding interactions. Lipophilic side chain of methionine in modified oxalyl aryl amino benzoic acid derivative [1b (a2, b2, c1, d)] lies in closer vicinity of hydrophobic region of protein consisted of Meth258 and Phe52 in comparison to active ligand. Docking Score in [1b (a2, b2, c1, d)] is -131.740Kcal/mol much better than active ligand score -98.584Kcal/mol. This information can be exploited to design PTP1B specific inhibitors. PMID:19238234

Closely related glycosylation patterns of recombinant human IL-2 expressed in a CHO cell line and natural IL-2

DOE Office of Scientific and Technical Information (OSTI.GOV)

Vita, N.; Magazin, M.; Marchese, E.

We report here the study of the glycosylation pattern of human recombinant (r) IL2 expressed in a Chinese hamster ovary (CHO) cell line. The human rIL2 secreted by this high-producing recombinant CHO cell line was metabolically radiolabelled with (35S)-methionine, or with (3H)-glucosamine and (3H)-galactose, purified to homogeneity, and then characterized. The electrophoretic analysis of the (35S)-methionine-labelled proteins present in the culture medium of the CHO cell line showed that the rIL2 represents approximately 12% of the total secreted proteins. Furthermore, pulse-chase experiments showed that the glycosylated rIL2 is synthesized and secreted within 30 min. The point of attachment and themore » structure of the carbohydrate moiety of the rIL2 was determined by: amino-terminal sequencing and fingerprint analysis of the 3H-labelled rIL2, mass spectroscopy of the amino-terminal tryptic octapeptide, and carbohydrate analysis after enzymatic (Vibrio cholerae neuraminidase and Aspergillus oryzae beta-galactosidase) or sulfuric acid hydrolysis. The results indicate that the recombinant protein possesses a sugar moiety O-linked to the threonine residue at position 3 of the polypeptide chain, and that sialic acid, galactose and N-acetyl galactosamine are components of this carbohydrate moiety. Taken together these results suggest that the recombinant molecule is identical to natural IL2.« less

Short-term methionine deprivation improves metabolic health via sexually dimorphic, mTORC1-independent mechanisms.

PubMed

Yu, Deyang; Yang, Shany E; Miller, Blake R; Wisinski, Jaclyn A; Sherman, Dawn S; Brinkman, Jacqueline A; Tomasiewicz, Jay L; Cummings, Nicole E; Kimple, Michelle E; Cryns, Vincent L; Lamming, Dudley W

2018-06-01

Obesity and diabetes are major challenges to global health, and there is an urgent need for interventions that promote weight loss. Dietary restriction of methionine promotes leanness and improves metabolic health in mice and humans. However, poor long-term adherence to this diet limits its translational potential. In this study, we develop a short-term methionine deprivation (MD) regimen that preferentially reduces fat mass, restoring normal body weight and glycemic control to diet-induced obese mice of both sexes. The benefits of MD do not accrue from calorie restriction, but instead result from increased energy expenditure. MD promotes increased energy expenditure in a sex-specific manner, inducing the fibroblast growth factor (Fgf)-21-uncoupling protein (Ucp)-1 axis only in males. Methionine is an agonist of the protein kinase mechanistic target of rapamycin complex (mTORC)-1, which has been proposed to play a key role in the metabolic response to amino acid-restricted diets. In our study, we used a mouse model of constitutive hepatic mTORC1 activity and demonstrate that suppression of hepatic mTORC1 signaling is not required for the metabolic effects of MD. Our study sheds new light on the mechanisms by which dietary methionine regulates metabolic health and demonstrates the translational potential of MD for the treatment of obesity and type 2 diabetes.-Yu, D., Yang, S. E., Miller, B. R., Wisinski, J. A., Sherman, D. S., Brinkman, J. A., Tomasiewicz, J. L., Cummings, N. E., Kimple, M. E., Cryns, V. L., Lamming, D. W. Short-term methionine deprivation improves metabolic health via sexually dimorphic, mTORC1-independent mechanisms.

Analysis of Loss-of-Function Mutants in Aspartate Kinase and Homoserine Dehydrogenase Genes Points to Complexity in the Regulation of Aspartate-Derived Amino Acid Contents1[OPEN

PubMed Central

2015-01-01

Biosynthesis of aspartate (Asp)-derived amino acids lysine (Lys), methionine (Met), threonine (Thr), and isoleucine involves monofunctional Asp kinases (AKs) and dual-functional Asp kinase-homoserine dehydrogenases (AK-HSDHs). Four-week-old loss-of-function Arabidopsis (Arabidopsis thaliana) mutants in the AK-HSDH2 gene had increased amounts of Asp and Asp-derived amino acids, especially Thr, in leaves. To explore mechanisms behind this phenotype, we obtained single mutants for other AK and AK-HSDH genes, generated double mutants from ak-hsdh2 and ak mutants, and performed free and protein-bound amino acid profiling, transcript abundance, and activity assays. The increases of Asp, Lys, and Met in ak-hsdh2 were also observed in ak1-1, ak2-1, ak3-1, and ak-hsdh1-1. However, the Thr increase in ak-hsdh2 was observed in ak-hsdh1-1 but not in ak1-1, ak2-1, or ak3-1. Activity assays showed that AK2 and AK-HSDH1 are the major contributors to overall AK and HSDH activities, respectively. Pairwise correlation analysis revealed positive correlations between the amount of AK transcripts and Lys-sensitive AK activity and between the amount of AK-HSDH transcripts and both Thr-sensitive AK activity and total HSDH activity. In addition, the ratio of total AK activity to total HSDH activity negatively correlates with the ratio of Lys to the total amount of Met, Thr, and isoleucine. These data led to the hypothesis that the balance between Lys-sensitive AKs and Thr-sensitive AK-HSDHs is important for maintaining the amounts and ratios of Asp-derived amino acids. PMID:26063505

The use of feed-grade amino acids in lactating sow diets.

PubMed

Greiner, Laura; Srichana, Pairat; Usry, James L; Neill, Casey; Allee, Gary L; Connor, Joseph; Touchette, Kevin J; Knight, Christopher D

2018-01-01

The use of feed grade amino acids can reduce the cost of lactation feed. With changing genetics, increasing feed costs, and higher number of pigs weaned with heavier wean weights further evaluation of higher inclusion levels of feed-grade amino acid in lactation diets than previously published is warranted. Two experiments (Exp.) were conducted to determine the optimal inclusion level of L -lysine HCl to be included in swine lactation diets while digestible lysine levels remain constant across dietary treatments and allowing feed grade amino acids to be added to the diet to maintain dietary ratios relative to lysine to maximize litter growth rate and sow reproductive performance. Furthermore, the studies were to evaluate minimal amino acid ratios relative to lysine that allows for optimal litter growth rate and sow reproductive performance. Exp. 1: Increasing L -lysine HCl resulted in similar gilt feed intake, litter, and reproductive performance. Average litter gain from birth to weaning was 2.51, 2.49, 2.59, 2.43, and 2.65 kg/d when gilts were fed 0.00, 0.075, 0.150, 0.225, and 0.30% L -lysine HCl, respectively. Exp. 2: The average litter gain from birth to weaning was 2.68, 2.73, 2.67, 2.70, and 2.64 kg/d ( P  < 0.70) when sows were fed 0.1, 0.2, 0.3, 0.4, and 0.4% L -lysine HCl plus valine, respectively. No other differences among dietary treatments were observed. Collectively, these studies demonstrate corn-soybean meal based lactation diets formulated with a constant SID lysine content for all parities containing up to 0.40% L -lysine HCl with only supplemental feed grade threonine and a methionine source have no detrimental effect on litter growth rate and subsequent total born.

The effect of thermal processing on protein quality and free amino acid profile of Terminalia catappa (Indian Almond) seed.

PubMed

Adu, O B; Ogundeko, T O; Ogunrinola, O O; Saibu, G M; Elemo, B O

2015-07-01

The study examined the effect of various processing methods- boiling, drying and roasting- on the in vitro and in vivo protein digestibility and free amino acid profiles of Terminalia catappa seed. Moisture and crude protein of the various samples were determined. In vitro protein digestibility was determined after pepsin digestion. For the in vivo experiment, defatted T. catappa based diet was fed to 3 weeks old Wistar rats for 4 weeks and compared with animals maintained on casein based and nitrogen- free diets. The biological value (BV), net protein utilisation (NPU) and protein efficiency ratio (PER) of the diets were determined. Free amino acid composition was carried out using thin layer chromatography. Moisture was highest in the boiled T. catappa seed (8.30 ± 0.00 %). The raw, roasted and dried seeds had 5.55 ± 0.07, 3.88 ± 0.22 and 3.75 ± 0.07 % respectively. Crude protein was 19.19, 18.89, 17.62 and 16.36 % in the dried, roasted, boiled and raw seeds respectively. Roasted T. catappa seed had the highest in vitro protein digestibility with 37.52 %, while the dried, boiled and raw samples had digestibility values of 27.57, 27.07 and 24.45 % respectively. All nine essential amino acids were present in T. catappa in high concentrations except methionine and tryptophan. Glutamate was present in the highest concentration. Also, free amino acids were higher in the processed seeds compared to the raw seed. Animals fed T. catappa diet compared favourably with the casein group, thus indicating that the protein is of good quality.

Simple and rapid analytical method for detection of amino acids in blood using blood spot on filter paper, fast-GC/MS and isotope dilution technique.

PubMed

Kawana, Shuichi; Nakagawa, Katsuhiro; Hasegawa, Yuki; Yamaguchi, Seiji

2010-11-15

A simple and rapid method for quantitative analysis of amino acids, including valine (Val), leucine (Leu), isoleucine (Ile), methionine (Met) and phenylalanine (Phe), in whole blood has been developed using GC/MS. In this method, whole blood was collected using a filter paper technique, and a 1/8 in. blood spot punch was used for sample preparation. Amino acids were extracted from the sample, and the extracts were purified using cation-exchange resins. The isotope dilution method using ²H₈-Val, ²H₃-Leu, ²H₃-Met and ²H₅-Phe as internal standards was applied. Following propyl chloroformate derivatization, the derivatives were analyzed using fast-GC/MS. The extraction recoveries using these techniques ranged from 69.8% to 87.9%, and analysis time for each sample was approximately 26 min. Calibration curves at concentrations from 0.0 to 1666.7 μmol/l for Val, Leu, Ile and Phe and from 0.0 to 333.3 μmol/l for Met showed good linearity with regression coefficients=1. The method detection limits for Val, Leu, Ile, Met and Phe were 24.2, 16.7, 8.7, 1.5 and 12.9 μmol/l, respectively. This method was applied to blood spot samples obtained from patients with phenylketonuria (PKU), maple syrup urine disease (MSUD), hypermethionine and neonatal intrahepatic cholestasis caused by citrin deficiency (NICCD), and the analysis results showed that the concentrations of amino acids that characterize these diseases were increased. These results indicate that this method provides a simple and rapid procedure for precise determination of amino acids in whole blood. Copyright © 2010 Elsevier B.V. All rights reserved.

Chemoproteomic profiling and discovery of protein electrophiles in human cells

NASA Astrophysics Data System (ADS)

Matthews, Megan L.; He, Lin; Horning, Benjamin D.; Olson, Erika J.; Correia, Bruno E.; Yates, John R.; Dawson, Philip E.; Cravatt, Benjamin F.

2017-03-01

Activity-based protein profiling (ABPP) serves as a chemical proteomic platform to discover and characterize functional amino acids in proteins on the basis of their enhanced reactivity towards small-molecule probes. This approach, to date, has mainly targeted nucleophilic functional groups, such as the side chains of serine and cysteine, using electrophilic probes. Here we show that 'reverse-polarity' (RP)-ABPP using clickable, nucleophilic hydrazine probes can capture and identify protein-bound electrophiles in cells. Using this approach, we demonstrate that the pyruvoyl cofactor of S-adenosyl-L-methionine decarboxylase (AMD1) is dynamically controlled by intracellular methionine concentrations. We also identify a heretofore unknown modification—an N-terminally bound glyoxylyl group—in the poorly characterized protein secernin-3. RP-ABPP thus provides a versatile method to monitor the metabolic regulation of electrophilic cofactors and discover novel types of electrophilic modifications on proteins in human cells.

The addition of choline to parenteral nutrition.

PubMed

Buchman, Alan L

2009-11-01

Choline is a quaternary amine endogenously synthesized from the amino acid methionine or absorbed via the portal circulation. It is ubiquitous in the diet, although it has a greater presence in organ meats. Choline is an essential component of all cell membranes, and has been considered a required dietary nutrient since 1998 by the US Institute of Medicine's Food and Nutrition Board. Choline is necessary for DNA repair, mediated by its role as a methyl donor. It also serves as the precursor for the neurotransmitter acetylcholine. Evidence has accumulated that hepatic steatosis, which occurs during parenteral nutrition therapy, develops as a result of choline deficiency because endogenous production of choline from parenterally infused methionine is deficient. In addition, memory deficits and skeletal muscle abnormalities have been described, and choline deficiency appears to activate cellular apoptosis. Provision of intravenous choline ameliorates hepatic steatosis associated with parenteral nutrition infusion.

Functional characterization of KanP, a methyltransferase from the kanamycin biosynthetic gene cluster of Streptomyces kanamyceticus.

PubMed

Nepal, Keshav Kumar; Yoo, Jin Cheol; Sohng, Jae Kyung

2010-09-20

KanP, a putative methyltransferase, is located in the kanamycin biosynthetic gene cluster of Streptomyces kanamyceticus ATCC12853. Amino acid sequence analysis of KanP revealed the presence of S-adenosyl-L-methionine binding motifs, which are present in other O-methyltransferases. The kanP gene was expressed in Escherichia coli BL21 (DE3) to generate the E. coli KANP recombinant strain. The conversion of external quercetin to methylated quercetin in the culture extract of E. coli KANP proved the function of kanP as S-adenosyl-L-methionine-dependent methyltransferase. This is the first report concerning the identification of an O-methyltransferase gene from the kanamycin gene cluster. The resistant activity assay and RT-PCR analysis demonstrated the leeway for obtaining methylated kanamycin derivatives from the wild-type strain of kanamycin producer. 2009 Elsevier GmbH. All rights reserved.

Influence of Threonine Metabolism on S-adenosyl-methionine and Histone Methylation

PubMed Central

Shyh-Chang, Ng; Locasale, Jason W.; Lyssiotis, Costas A.; Zheng, Yuxiang; Teo, Ren Yi; Ratanasirintrawoot, Sutheera; Zhang, Jin; Onder, Tamer; Unternaehrer, Juli J.; Zhu, Hao; Asara, John M.; Daley, George Q.; Cantley, Lewis C.

2013-01-01

Threonine is the only amino acid critically required for the pluripotency of mouse embryonic stem cells (mESCs) but the detailed mechanism remains unclear. We found that threonine (Thr) and S-adenosyl-methionine (SAM) metabolism are coupled in pluripotent stem cells, resulting in regulation of histone methylation. Isotope labeling of mESCs revealed that Thr provides a substantial fraction of both the cellular glycine (Gly) and the acetyl-coenzyme A (CoA) needed for SAM synthesis. Depletion of Thr from the culture medium or threonine dehydrogenase (Tdh) from mESCs decreased accumulation of SAM and decreased tri-methylation of histone H3 lysine-4 (H3K4me3), leading to slowed growth, and increased differentiation. Thus abundance of SAM appears to influence H3K4me3, providing a possible mechanism by which modulation of a metabolic pathway might influence stem cell fate. PMID:23118012

In silico mutation analysis of non-structural protein-5 (NS5) dengue virus

NASA Astrophysics Data System (ADS)

Puspitasari, R. D.; Tambunan, U. S. F.

2017-04-01

Dengue fever is a world disease. It is endemic in more than 100 countries. Information about the effect of mutations in the virus is important in drug design and development. In this research, we studied the effect of mutation on NS5 dengue virus. NS5 is the large protein containing 67% amino acid similarity in DENV 1-4 and has multifunctional enzymatic activities. Dengue virus is an RNA virus that has very high mutation frequency with an average of 100 times higher than DNA mutations, and the accumulation of mutations will be possible to generate the new serotype. In this study, we report that mutation occurs in NS5 of DENV serotype 3, glutamine mutates into methionine at position 10 and threonine mutates into isoleucine at position 55. These residues are part of the domain named S-Adenosyl-L-Methionine-Dependent Methyltransferase (IPR029063).

A new method for the extraction and purification of K99 pili from enterotoxigenic Escherichia coli and their characterization.

PubMed Central

Altmann, K; Pyliotis, N A; Mukkur, T K

1982-01-01

It was found that K99 pili from enterotoxigenic Escherichia coli (of bovine origin) could be extracted by treatment with 3M-KSCN solution. The K99 pili were purified by preparative isoelectric focusing to apparent homogeneity as judged by the presence of a single band on sodium dodecyl sulphate/polyacrylamide-gel electrophoresis; the molecular weight of this component was calculated to be 12 600 +/- 300. This indicated that the K99 pili were composed of a single subunit. On analytical ultracentrifugation, a single boundary with an s20,w of 12.2 S at a concentration of 0.42 mg/ml was observed. The average length of purified pili at zero concentration was approx. 160 nm and the diameter was 7.4 +/- 0.6 nm. Amino acid analysis of the purified K99 pili revealed that sulphur-containing amino acids, cysteine and methionine, were absent. Aromatic amino acids, phenylalanine and tyrosine, previously reported to be absent [Isaacson (1977) Infect. Immun. 15. 272-279], constituted 7.14% of the total amino acid residues present. On immunoelectrophoresis, purified K99 pili migrated towards the cathode and caused mannose-resistant haemagglutination of horse, but not of sheep or guinea-pig, red blood cells. Pili from enterotoxigenic E. coli of porcine and human origin and from another bacterial species, namely Fusiformis nodosus, could also be extracted by the treatment of respective micro-organisms with 3 M-KSCN. Images PLATE 1 Fig. 3. Fig. 5. PMID:6124240

Characterization, production, and purification of leucocin H, a two-peptide bacteriocin from Leuconostoc MF215B.

PubMed

Blom, H; Katla, T; Holck, A; Sletten, K; Axelsson, L; Holo, H

1999-07-01

Leuconostoc MF215B was found to produce a two-peptide bacteriocin referred to as leucocin H. The two peptides were termed leucocin Halpha and leucocin Hbeta. When acting together, they inhibit, among others, Listeria monocytogenes, Bacillus cereus, and Clostridium perfringens. Production of leucocin H in growth medium takes place at temperatures down to 6 degrees C and at pH below 7. The highest activity of leucocin H in growth medium was demonstrated in the late exponential growth phase. The bacteriocin was purified by precipitation with ammonium sulfate, ion-exchange (SP Sepharose) and reverse phase chromatography. Upon purification, specific activity increased 10(5)-fold, and the final specific activity was 2 x 10(7) BU/OD280. Amino acid composition analyses of leucocin Halpha and leucocin Hbeta indicated that both peptides consisted of around 40 amino acid residues. Their N-termini were blocked for Edman degradation, and the methionin residues of leucocin Hbeta did not respond to Cyanogen Bromide (CNBr) cleavage. Absorbance at 280 nm indicated the presence of tryptophan residues and tryptophan-fracturing opened for partial sequencing by Edman degradation. From leucocin Halpha, the sequence of 20 amino acids was obtained; from leucocin Hbeta the sequence of 28 amino acid residues was obtained. No sequence homology to other known bacteriocins could be demonstrated. It also appeared that the two peptides themselves shared little or no sequence homology. The presence of soy oil did not affect the activity of leucocin H in agar.

Syntrophic exchange in synthetic microbial communities

PubMed Central

Mee, Michael T.; Collins, James J.; Church, George M.; Wang, Harris H.

2014-01-01

Metabolic crossfeeding is an important process that can broadly shape microbial communities. However, little is known about specific crossfeeding principles that drive the formation and maintenance of individuals within a mixed population. Here, we devised a series of synthetic syntrophic communities to probe the complex interactions underlying metabolic exchange of amino acids. We experimentally analyzed multimember, multidimensional communities of Escherichia coli of increasing sophistication to assess the outcomes of synergistic crossfeeding. We find that biosynthetically costly amino acids including methionine, lysine, isoleucine, arginine, and aromatics, tend to promote stronger cooperative interactions than amino acids that are cheaper to produce. Furthermore, cells that share common intermediates along branching pathways yielded more synergistic growth, but exhibited many instances of both positive and negative epistasis when these interactions scaled to higher dimensions. In more complex communities, we find certain members exhibiting keystone species-like behavior that drastically impact the community dynamics. Based on comparative genomic analysis of >6,000 sequenced bacteria from diverse environments, we present evidence suggesting that amino acid biosynthesis has been broadly optimized to reduce individual metabolic burden in favor of enhanced crossfeeding to support synergistic growth across the biosphere. These results improve our basic understanding of microbial syntrophy while also highlighting the utility and limitations of current modeling approaches to describe the dynamic complexities underlying microbial ecosystems. This work sets the foundation for future endeavors to resolve key questions in microbial ecology and evolution, and presents a platform to develop better and more robust engineered synthetic communities for industrial biotechnology. PMID:24778240

Molecular characterization and intermolecular interaction of coat protein of Prunus necrotic ringspot virus: implications for virus assembly.

PubMed

Kulshrestha, Saurabh; Hallan, Vipin; Sharma, Anshul; Seth, Chandrika Attri; Chauhan, Anjali; Zaidi, Aijaz Asghar

2013-09-01

Coat protein (CP) and RNA3 from Prunus necrotic ringspot virus (PNRSV-rose), the most prevalent virus infecting rose in India, were characterized and regions in the coat protein important for self-interaction, during dimer formation were identified. The sequence analysis of CP and partial RNA 3 revealed that the rose isolate of PNRSV in India belongs to PV-32 group of PNRSV isolates. Apart from the already established group specific features of PV-32 group member's additional group-specific and host specific features were also identified. Presence of methionine at position 90 in the amino acid sequence alignment of PNRSV CP gene (belonging to PV-32 group) was identified as the specific conserved feature for the rose isolates of PNRSV. As protein-protein interaction plays a vital role in the infection process, an attempt was made to identify the portions of PNRSV CP responsible for self-interaction using yeast two-hybrid system. It was found (after analysis of the deletion clones) that the C-terminal region of PNRSV CP (amino acids 153-226) plays a vital role in this interaction during dimer formation. N-terminal of PNRSV CP is previously known to be involved in CP-RNA interactions, but our results also suggested that N-terminal of PNRSV CP represented by amino acids 1-77 also interacts with C-terminal (amino acids 153-226) in yeast two-hybrid system, suggesting its probable involvement in the CP-CP interaction.

Effect of ascorbic acid or increasing metabolizable energy level with or without supplementation of some essential amino acids on productive and physiological traits of slow-growing chicks exposed to chronic heat stress.

PubMed

Attia, Y A; Hassan, R A; Tag El-Din, A E; Abou-Shehema, B M

2011-12-01

Four hundred and twenty, 21-day-old slow-growing chicks were divided randomly into seven treatments, each containing five replicates. Each replicate was kept in a 1 × 1-m floor pen. One treatment was kept under thermo-neutral conditions in a semi-open house and fed a corn-soybean meal diet (positive control). The other six groups were kept under chronic heat stress (CHS) at 38 °C and 60% RH for 4 h from 12:00 to 16:00 pm for three successive days per week. Chicks in CHS treatments were fed a corn-soybean meal diet without (negative control) or with increasing metabolizable energy (ME) level by oil supplementation alone, or also with increasing some essential amino acids (EAA) such as methionine (Met), methionine and lysine (Met+Lys) or methionine, lysine and arginine (Met+Lys+Arg) or supplemented with 250 mg of ascorbic acid (AA)/kg. CHS impaired (p < 0.05) growth performance, increased plasma triglycerides and total serum Ca while decreasing (p < 0.05) plasma glucose and total serum protein. Meanwhile 250 mg AA/kg diet or an increasing ME without or with some EAA partially alleviated (p < 0.0001) the negative effect of CHS on growth while increasing (p < 0.05) feed intake and improving (p < 0.05) feed:gain ratio (F:G) and crude protein (CP) digestibility (p < 0.05). AA or increasing ME with or without EAA increased (p < 0.05) percentage dressing, liver and giblets to those of the positive control. AA or increasing ME with or without EAA partially alleviated the negative effect of CHS on blood pH, packed cell volume (PCV), haemoglobin (Hgb), total serum protein and total Ca, plasma glucose and triglyceride, rectal temperature and respiration rate. Increasing ME level improved chickens' tolerance to CHS without a significant difference from those supplemented with AA. However, increasing Met, Lys and Arg concentration did not improve performance over that recorded with increasing ME level alone. Under CHS, 250 mg AA/kg diet or increasing ME level by addition of 3% vegetable oil could be an useful approach to improve productive and physiological traits of slow-growing chicks, which may be applicable also to fast-growing one. © 2010 Blackwell Verlag GmbH.

Effect of biogenic fermentation impurities on lactic acid hydrogenation to propylene glycol.

PubMed

Zhang, Zhigang; Jackson, James E; Miller, Dennis J

2008-09-01

The effect of residual impurities from glucose fermentation to lactic acid (LA) on subsequent ruthenium-catalyzed hydrogenation of LA to propylene glycol (PG) is examined. Whereas refined LA feed exhibits stable conversion to PG over carbon-supported ruthenium catalyst in a trickle bed reactor, partially refined LA from fermentation shows a steep decline in PG production over short (<40 h) reaction times followed by a further slow decay in performance. Addition of model impurities to refined LA has varying effects: organic acids, sugars, or inorganic salts have little effect on conversion; alanine, a model amino acid, results in a strong but reversible decline in conversion via competitive adsorption between alanine and LA on the Ru surface. The sulfur-containing amino acids cysteine and methionine irreversibly poison the catalyst for LA conversion. Addition of 0.1 wt% albumin as a model protein leads to slow decline in rate, consistent with pore plugging or combined pore plugging and poisoning of the Ru surface. This study points to the need for integrated design and operation of biological processes and chemical processes in the biorefinery in order to make efficient conversion schemes viable.

S-Isovaline Contained in Meteorites, Induces Enantiomeric Excess in D,L-glutamic Acid During Recrystallization

NASA Astrophysics Data System (ADS)

Kojo, Shosuke

2015-06-01

S-Isovaline (S-Iva: 6.7 mmol) and D,L-glutamic acid (Glu: 2 mmol) were dissolved in 10 ml of hot water, and the resulting solution was divided in 5 vessels. After recrystallization, the crystals were collected from each vessel, and the enantiomeric excess (ee) of Glu was determined with chemical derivatization using 1-fluoro-2,4-dinitrophenyl- 5-L-leucinamide followed by high-performance liquid chromatography. Ten crystallizations provided all D-rich Glu with ee values of 2.69 % ± 0.81 % (mean ± standard deviation), and those using R-Iva provided all L-rich Glu with ee values of 6.24 % ± 2.20 %. Five recrystallizations of D,L-Glu alone provided ee values of 0.474 % ± 0.33 %. The differences among these three ee values were statistically significant, showing that S-Iva, which was present in meteorites caused a significant induction of ee in this physiological amino acid. This is the first outcome that S-Iva induced ee changes in a physiological amino acid. S-Iva did not induce any ee changes in D,L-asparagine, leucine, valine, methionine, phenylalanine, tryptophan, glutamine, tyrosine, aspartic acid, or histidine under similar recrystallizations.

Thermodynamic Effects of Noncoded and Coded Methionine Substitutions in Calmodulin

PubMed Central

Yamniuk, Aaron P.; Ishida, Hiroaki; Lippert, Dustin; Vogel, Hans J.

2009-01-01

The methionine residues in the calcium (Ca2+) regulatory protein calmodulin (CaM) are structurally and functionally important. They are buried within the N- and C-domains of apo-CaM but become solvent-exposed in Ca2+-CaM, where they interact with numerous target proteins. Previous structural studies have shown that methionine substitutions to the noncoded amino acids selenomethionine, ethionine, or norleucine, or mutation to leucine do not impact the main chain structure of CaM. Here we used differential scanning calorimetry to show that these substitutions enhance the stability of both domains, with the largest increase in melting temperature (19–26°C) achieved with leucine or norleucine in the apo-C-domain. Nuclear magnetic resonance spectroscopy experiments also revealed the loss of a slow conformational exchange process in the Leu-substituted apo-C-domain. In addition, isothermal titration calorimetry experiments revealed considerable changes in the enthalpy and entropy of target binding to apo-CaM and Ca2+-CaM, but the free energy of binding was largely unaffected due to enthalpy-entropy compensation. Collectively, these results demonstrate that noncoded and coded methionine substitutions can be accommodated in CaM because of the structural plasticity of the protein. However, adjustments in side-chain packing and dynamics lead to significant differences in protein stability and the thermodynamics of target binding. PMID:19217866

Ultraviolet-B radiation modifies the quantitative and qualitative profile of flavonoids and amino acids in grape berries.

PubMed

Martínez-Lüscher, J; Torres, N; Hilbert, G; Richard, T; Sánchez-Díaz, M; Delrot, S; Aguirreolea, J; Pascual, I; Gomès, E

2014-06-01

Grapevine cv. Tempranillo fruit-bearing cuttings were exposed to supplemental ultraviolet-B (UV-B) radiation under controlled conditions, in order to study its effect on grape traits, ripening, amino acids and flavonoid profile. The plants were exposed to two doses of UV-B biologically effective (5.98 and 9.66kJm(-2)d(-1)), applied either from fruit set to ripeness or from the onset of veraison to ripeness. A 0kJm(-2)d(-1) treatment was included as a control. UV-B did not significantly modify grape berry size, but increased the relative mass of berry skin. Time to reach ripeness was not affected by UV-B, which may explain the lack of changes in technological maturity. The concentration of must extractable anthocyanins, colour density and skin flavonols were enhanced by UV-B, especially in plants exposed from fruit set. The quantitative and qualitative profile of grape skin flavonols were modified by UV-B radiation. Monosubstituted flavonols relative abundance increased proportionally to the accumulated UV-B doses. Furthermore, trisubstituted forms, which where predominant in non-exposed berries, were less abundant as UV-B exposure increased. Although total free amino acid content remained unaffected by the treatments, the increased levels of gamma-aminobutyric acid (GABA), as well as the decrease in threonine, isoleucine, methionine, serine and glycine, revealed a potential influence of UV-B on the GABA-mediated signalling and amino acid metabolism. UV-B had an overall positive impact on grape berry composition. Copyright © 2014 Elsevier Ltd. All rights reserved.

Effects of supplements of folic acid, vitamin B12, and rumen-protected methionine on whole body metabolism of methionine and glucose in lactating dairy cows.

PubMed

Preynat, A; Lapierre, H; Thivierge, M C; Palin, M F; Matte, J J; Desrochers, A; Girard, C L

2009-02-01

The present experiment was undertaken to determine the effects of dietary supplements of rumen-protected methionine and intramuscular injections of folic acid and vitamin B(12), given 3 wk before to 16 wk after calving, on glucose and methionine metabolism of lactating dairy cows. Twenty-four multiparous Holstein cows were assigned to 6 blocks of 4 cows each according to their previous milk production. Within each block, 2 cows were fed a diet estimated to supply methionine as 1.83% metabolizable protein, equivalent to 76% of methionine requirement, whereas the 2 other cows were fed the same diet supplemented daily with 18 g of rumen-protected methionine. Within each diet, the cows were administrated either no vitamin supplement or weekly intramuscular injections of 160 mg of folic acid plus 10 mg of vitamin B(12.) To investigate metabolic changes at 12 wk of lactation, glucose and methionine kinetics were measured by isotope dilution using infusions of 3[U-(13)C]glucose, [(13)C]NaHCO(3) and 3[1-(13)C,(2)H(3)] methionine. Milk and plasma concentrations of folic acid and vitamin B(12) increased with vitamin injections. Supplementary B-vitamins increased milk production from 34.7 to 38.9 +/- 1.0 kg/d and increased milk lactose, protein, and total solids yields. Whole-body glucose flux tended to increase with vitamin supplementation with a similar quantitative magnitude as the milk lactose yield increase. Vitamin supplementation increased methionine utilization for protein synthesis through increased protein turnover when methionine was deficient and through decreased methionine oxidation when rumen-protected methionine was fed. Vitamin supplementation decreased plasma concentrations of homocysteine independently of rumen-protected methionine feeding, although no effect of vitamin supplementation was measured on methionine remethylation, but this could be due to the limitation of the technique used. Therefore, the effects of these B-vitamins on lactation performance were not mainly explained by methionine economy because of a more efficient methylneogenesis but were rather related to increased glucose availability and changes in methionine metabolism.

Effects of Rice Bran, Flax Seed, and Sunflower Seed on Growth Performance, Carcass Characteristics, Fatty Acid Composition, Free Amino Acid and Peptide Contents, and Sensory Evaluations of Native Korean Cattle (Hanwoo)

PubMed Central

Choi, Chang Bon; Kwon, Hana; Kim, Sung Il; Yang, Un Mok; Lee, Ju Hwan; Park, Eun Kyu

2016-01-01

This study was conducted to evaluate the effect of dietary supplementation with rice bran, flax seed, or sunflower seed to finishing native Korean cattle (Hanwoo) on growth performances, carcass characteristics, fatty acid composition, free amino acid and peptide contents, and sensory evaluations of Longissimus muscle (LM). A total of 39 Hanwoo steers (average age of 22.2 mo and average body weight (BW) of 552.2 kg) were randomly divided into Control, rice bran (RB), flax seed (FS), or Sunflower seed (SS) groups. The steers were group fed for 273 d until they reached an average age of 31.2 mo. Final BW was 768.2, 785.8, 786.2, and 789.0 kg, and average daily gain was 0.79, 0.85, 0.82, and 0.84 kg for the Control, RS, FS, and SS groups, respectively (p>0.05). Fat thickness of the FS group (19.8 mm) was greater (p<0.05) than that of the other groups. Final yield grade converted into numerical values was 2.0 for the RB group, 1.7 for the Control and SS groups, and 1.4 for the FS group. Marbling degrees for the Control, SS, RB, and FS groups were 5.3, 5.1, 4.7, and 4.6, respectively. Percentages of palmitic acid (C16:0), stearic acid (C18:0), and arachidic acid (C20:0) in the LM were not different among the groups. Palmitoleic (C16:1) acid was higher (p<0.05) in the SS group. The concentration of oleic acid was highest (p<0.05) in the Control group (47.73%). The level of linolenic acid (C18:3) was 2.3 times higher (p<0.05) in the FS group compared to the other groups. Methionine concentration was (p<0.05) higher in FS (1.7 mg/100 g) and SS (1.2 mg/100 g) steers than in the Control or RB groups. Glutamic acid and α-aminoadipic acid (α-AAA) contents were (p<0.05) higher in the FS group compared to the other groups. LM from the FS group had numerically higher (p>0.05) scores for flavor, umami, and overall palatability in sensory evaluations. In conclusion, supplementation of flax seed to diets of finishing Hanwoo steers improved sensory evaluations which might have been caused by increases in flavor related amino acids such as methionine, glutamic acid and α-AAA and peptides, anserine and carnosine, and their complex reactions. PMID:26732444

The elastase-PK101 structure: Mechanism of an ultrasensitive activity-based probe revealed

DOE PAGES

Lechtenberg, Bernhard C.; Robinson, Howard R.; Kasperkiewicz, Paulina; ...

2015-01-22

Human neutrophil elastase (HNE) plays a central role in neutrophil host defense, but its broad specificity makes HNE a difficult target for both inhibitor and probe development. Recently, we identified the unnatural amino acid containing activity-based probe PK101, which exhibits astounding sensitivity and selectivity for HNE, yet completely lacks mechanistic explanation for its unique characteristics. Here, we present the crystal structure of the HNE-PK101 complex which not only reveals the basis for PK101 ultrasensitivity but also uncovers so far unrecognized HNE features. Strikingly, the Nle( O-Bzl) function in the P4 position of PK101 reveals and leverages an “exo-pocket” on HNEmore » as a critical factor for selectivity. Furthermore, the PK101 P3 position harbors a methionine dioxide function, which mimics a post-translationally oxidized methionine residue and forms a critical hydrogen bond to the backbone amide of Gly219 of HNE. Gly219 resides in a Gly–Gly motif that is unique to HNE, yet compulsory for this interaction. Consequently, this feature enables HNE to accommodate substrates that have undergone methionine oxidation, which constitutes a hallmark post-translational modification of neutrophil signaling.« less

The Methionine-aromatic Motif Plays a Unique Role in Stabilizing Protein Structure*

PubMed Central

Valley, Christopher C.; Cembran, Alessandro; Perlmutter, Jason D.; Lewis, Andrew K.; Labello, Nicholas P.; Gao, Jiali; Sachs, Jonathan N.

2012-01-01

Of the 20 amino acids, the precise function of methionine (Met) remains among the least well understood. To establish a determining characteristic of methionine that fundamentally differentiates it from purely hydrophobic residues, we have used in vitro cellular experiments, molecular simulations, quantum calculations, and a bioinformatics screen of the Protein Data Bank. We show that approximately one-third of all known protein structures contain an energetically stabilizing Met-aromatic motif and, remarkably, that greater than 10,000 structures contain this motif more than 10 times. Critically, we show that as compared with a purely hydrophobic interaction, the Met-aromatic motif yields an additional stabilization of 1–1.5 kcal/mol. To highlight its importance and to dissect the energetic underpinnings of this motif, we have studied two clinically relevant TNF ligand-receptor complexes, namely TRAIL-DR5 and LTα-TNFR1. In both cases, we show that the motif is necessary for high affinity ligand binding as well as function. Additionally, we highlight previously overlooked instances of the motif in several disease-related Met mutations. Our results strongly suggest that the Met-aromatic motif should be exploited in the rational design of therapeutics targeting a range of proteins. PMID:22859300

Characterisation of methionine adenosyltransferase from Mycobacterium smegmatis and M. tuberculosis

PubMed Central

Berger, Bradley J; Knodel, Marvin H

2003-01-01

Background Tuberculosis remains a serious world-wide health threat which requires the characterisation of novel drug targets for the development of future antimycobacterials. One of the key obstacles in the definition of new targets is the large variety of metabolic alterations that occur between cells in the active growth and chronic/dormant phases of tuberculosis. The ideal biochemical target should be active in both growth phases. Methionine adenosyltransferase, which catalyses the formation of S-adenosylmethionine from methionine and ATP, is involved in polyamine biosynthesis during active growth and is also required for the methylation and cyclopropylation of mycolipids necessary for survival in the chronic phase. Results The gene encoding methionine adenosyltransferase has been cloned from Mycobacterium tuberculosis and the model organism M. smegmatis. Both enzymes retained all amino acids known to be involved in catalysing the reaction. While the M. smegmatis enzyme could be functionally expressed, the M. tuberculosis homologue was insoluble and inactive under a large variety of expression conditions. For the M. smegmatis enzyme, the Vmax for S-adenosylmethionine formation was 1.30 μmol/min/mg protein and the Km for methionine and ATP was 288 μM and 76 μM respectively. In addition, the enzyme was competitively inhibited by 8-azaguanine and azathioprine with a Ki of 4.7 mM and 3.7 mM respectively. Azathioprine inhibited the in vitro growth of M. smegmatis with a minimal inhibitory concentration (MIC) of 500 μM, while the MIC for 8-azaguanine was >1.0 mM. Conclusion The methionine adenosyltransferase from both organisms had a primary structure very similar those previously characterised in other prokaryotic and eukaryotic organisms. The kinetic properties of the M. smegmatis enzyme were also similar to known prokaryotic methionine adenosyltransferases. Inhibition of the enzyme by 8-azaguanine and azathioprine provides a starting point for the synthesis of higher affinity purine-based inhibitors. PMID:12809568

Development of an in vivo Assay for Mistranslation: Inducing Activity of Pollutants and Characterization of Amino Acid Substitutions.

DTIC Science & Technology

1983-11-23

during their replication in B. subtilis cells. IV. CLONING THE 0.3 GENE OF COLIPHAGE T7 IN SPP1v We are currently investigating the fidelity of synthesis...of the product of the 0.3 gene of coliphage T7 in infected cells of E.. g by determining the frequency of misincorporation of S-cysteine into this...using a sealed hydrolysis chamber. BC1 was evaporated under vacuum and the hydrolysate resuspended in water . Unlabeled cysteine (12 ug) and methionine

Plasma Amino Acid Responses After Consumption of Beverages with Varying Protein Type

DTIC Science & Technology

2009-07-01

lysine 0.92 1.32 0.91 methionine 0.31 0.28 OJI phenylalanine 0.58 0.46 0.61 threonine 0.49 0.60 0.52 tryptophan 0.18 0.29 0.13 valine 0.69 0.64 0.68...threonine. serine. glutamine. proline. glycine, alanine, valine. isoleucine. leucine. tyrosine, phenylalanine . lysine, histidine, and arginine (Terrlink. van...with peak concentration in parentheses, were 2 ± 2 (45ŕ" ± 34%), 4 ± 3 (50% ± 32%). and 3 ± 3 mg/ dl (79% ± 37%). respectively. Postexercise, WP. CAS

Regulation of myofibrillar accumulation in chick muscle cultures - Evidence for the involvement of calcium and lysosomes in non-uniform turnover of contractile proteins

NASA Technical Reports Server (NTRS)

Silver, Geri; Etlinger, Joseph D.

1985-01-01

The effects of calcium on the synthesis and the degradation of individual myofibrillar proteins were investigated using primary chick-leg skeletal muscle cultures labeled with S-35-methionine (for protein accumulation experiments) or Ca(2+)-45 (for calcium efflux experiments). It was found that the turnover of individual contractile proteins is regulated nonuniformly by a calcium-dependent mechanism involving lysosomes. The results also indicate that contractile proteins are released from the myofibril before their breakdown to amino acids.

Nutritional quality of extruded kidney bean (Phaseolus vulgaris L. var. Pinto) and its effects on growth and skeletal muscle nitrogen fractions in rats.

PubMed

Marzo, F; Alonso, R; Urdaneta, E; Arricibita, F J; Ibáñez, F

2002-04-01

The influence of extrusion cooking on the protein content, amino acid profile, and concentration of antinutritive compounds (phytic acid, condensed tannins, polyphenols, trypsin, chymotrypsin, alpha-amylase inhibitors, and hemagglutinating activity) in kidney bean seeds (Phaseolus vulgaris L. var. Pinto) was investigated. Growing male rats were fed diets based on casein containing raw or extruded kidney beans with or without methionine supplementation for 8 or 15 d. Rates of growth, food intake, and protein efficiency ratio were measured and the weight of the gastrocnemius muscle and the composition of its nitrogenous fraction was determined. Extrusion cooking reduced (P < 0.01) phytic acid, condensed tannins, and trypsin, chymotrypsin, and (alpha-amylase inhibitory activities. Furthermore, hemagglutinating activity was abolished by extrusion treatment. Protein content was not affected by this thermal treatment. Rats fed raw kidney bean lost BW rapidly and the majority died by 9 d. Pretreatment of the beans by extrusion cooking improved food intake and utilization by the rats and they gained BW. Supplementation of extruded kidney bean with methionine further enhanced (P < 0.01) food conversion efficiency and growth. However, BW gains and muscle composition still differed (P < 0.01) from those of rats fed a high-quality protein.

Salt-Stress Response Mechanisms Using de Novo Transcriptome Sequencing of Salt-Tolerant and Sensitive Corchorus spp. Genotypes

PubMed Central

Yang, Zemao; Lu, Ruike; Dai, Zhigang; Yan, An; Tang, Qing; Cheng, Chaohua; Xu, Ying; Yang, Wenting; Su, Jianguang

2017-01-01

High salinity is a major environmental stressor for crops. To understand the regulatory mechanisms underlying salt tolerance, we conducted a comparative transcriptome analysis between salt-tolerant and salt-sensitive jute (Corchorus spp.) genotypes in leaf and root tissues under salt stress and control conditions. In total, 68,961 unigenes were identified. Additionally, 11,100 unigenes (including 385 transcription factors (TFs)) exhibited significant differential expression in salt-tolerant or salt-sensitive genotypes. Numerous common and unique differentially expressed unigenes (DEGs) between the two genotypes were discovered. Fewer DEGs were observed in salt-tolerant jute genotypes whether in root or leaf tissues. These DEGs were involved in various pathways, such as ABA signaling, amino acid metabolism, etc. Among the enriched pathways, plant hormone signal transduction (ko04075) and cysteine/methionine metabolism (ko00270) were the most notable. Eight common DEGs across both tissues and genotypes with similar expression profiles were part of the PYL-ABA-PP2C (pyrabactin resistant-like/regulatory components of ABA receptors-abscisic acid-protein phosphatase 2C). The methionine metabolism pathway was only enriched in salt-tolerant jute root tissue. Twenty-three DEGs were involved in methionine metabolism. Overall, numerous common and unique salt-stress response DEGs and pathways between salt-tolerant and salt-sensitive jute have been discovered, which will provide valuable information regarding salt-stress response mechanisms and help improve salt-resistance molecular breeding in jute. PMID:28927022

PLASMA PROTEIN PRODUCTION INFLUENCED BY AMINO ACID MIXTURES AND LACK OF ESSENTIAL AMINO ACIDS

PubMed Central

Madden, S. C.; Anderson, F. W.; Donovan, J. C.; Whipple, G. H.

1945-01-01

When blood plasma proteins are depleted by bleeding with return of red cells suspended in saline (plasmapheresis) it is possible to bring dogs to a steady state of hypoproteinemia and a constant level of plasma protein production if the diet nitrogen intake is controlled and limited. Such dogs are outwardly normal but have a lowered resistance to infection and intoxication and probably to vitamin deficiency. When the diet nitrogen is provided by certain mixtures of the ten growth essential amino acids plus glycine, given intravenously at a rapid rate, plasma protein production is good. The same mixture absorbed subcutaneously at a slower rate may be slightly better utilized. Fed orally the same mixture is better utilized and associated with a lower urinary nitrogen excretion. An ample amino acid mixture for the daily intake of a 10 kilo dog may contain in grams dl-threonine 1.4, dl-valine 3, dl-leucine 3, dl-isoleucine 2, l(+)-lysine·HCl·H2O 2.2, dl-tryptophane 0.3, dl-phenylalanine 2, dl-methionine 1.2, l(+)-histidine·HCl·H2O 1, l(+)-arginine·HCl 1, and glycine 2. Half this quantity is inadequate and not improved by addition of a mixture of alanine, serine, norleucine, proline, hydroxyproline, and tyrosine totalling 1.4 gm. Aspartic acid appears to induce vomiting when added to a mixture of amino acids. The same response has been reported for glutamic acid (8). Omission from the intake of leucine or of leucine and isoleucine results in negative nitrogen balance and rapid weight loss but plasma protein production may be temporarily maintained. It is possible that leucine may be captured from red blood cell destruction. Tryptophane deficiency causes an abrupt decline in plasma protein production. No decline occurred during 2 weeks of histidine deficiency but the urinary nitrogen increased to negative balance. Plasma protein production may be impaired during conditions of dietary deficiency not related to the protein or amino acid intake. Skin lesions and liver function impairment are described. Unidentified factors present in liver and yeast appear to be involved. PMID:19871490

Serum free amino acid concentration in hepatic lipidosis of dairy cows in the periparturient period.

PubMed

Shibano, Ken-ichi; Kawamura, Seiichi

2006-04-01

Blood samples were taken from eight multiparous cows at a dairy farm on eight occasions between the prepartum period and peak lactation to study the serum concentrations of amino acids and biochemical constituents. The cows were classified as having either severe hepatic lipidosis (HL) or non-hepatic lipidosis (non-HL) according to their clinical condition after calving and changes in serum biochemical parameters. The serum concentrations of beta-hydroxybutyric acid were higher in the HL group than in the non-HL group (ANOVA: p<0.01). The serum concentrations of methionine (Met), phenylalanine, and arginine were significantly different between the two groups (ANOVA: p<0.05). In particular, the Met levels were significantly low for 14 days after calving in the HL group (p<0.05), although Met levels in the HL group tended to be lower than the values in the non-HL group until 30 days after calving, starting 14 days before calving. The results suggest that an insufficiency of Met during the periparturient period is related to the development of hepatic lipidosis.

MC1R studies in dogs with melanistic mask or brindle patterns.

PubMed

Schmutz, S M; Berryere, T G; Ellinwood, N M; Kerns, J A; Barsh, G S

2003-01-01

Black mask is a characteristic pattern in which red, yellow, tan, fawn, or brindle dogs exhibit a melanistic muzzle which may extend up onto the ears. Melanistic mask is inherited in several breeds as an autosomal dominant trait, and appears to be a fixed trait in a few breeds of dogs. A MC1R nonsense mutation, R306ter, has been shown to cause a completely red or yellow coat color in certain breeds such as Irish setters, yellow Labrador retrievers, and golden retrievers. The amino acid sequence for the melanocortin receptor 1 gene (MC1R) was examined in 17 dogs with melanistic masks from seven breeds, 19 dogs without melanistic masks, and 7 dogs in which their coat color made the mask difficult to distinguish. We also examined nine brindle dogs of four breeds, including three dogs who also had a black mask. No consistent amino acid change was observed in the brindle dogs. All dogs with a melanistic mask had at least one copy of a valine substitution for methionine at amino acid 264 (M264V) and none were homozygous for the premature stop codon (R306ter). These results suggest that black mask, but not brindle, is caused by a specific MC1R allele.

Structure-Based Engineering of an Artificially Generated NADP+-Dependent d-Amino Acid Dehydrogenase.

PubMed

Hayashi, Junji; Seto, Tomonari; Akita, Hironaga; Watanabe, Masahiro; Hoshino, Tamotsu; Yoneda, Kazunari; Ohshima, Toshihisa; Sakuraba, Haruhiko

2017-06-01

A stable NADP + -dependent d-amino acid dehydrogenase (DAADH) was recently created from Ureibacillus thermosphaericus meso -diaminopimelate dehydrogenase through site-directed mutagenesis. To produce a novel DAADH mutant with different substrate specificity, the crystal structure of apo-DAADH was determined at a resolution of 1.78 Å, and the amino acid residues responsible for the substrate specificity were evaluated using additional site-directed mutagenesis. By introducing a single D94A mutation, the enzyme's substrate specificity was dramatically altered; the mutant utilized d-phenylalanine as the most preferable substrate for oxidative deamination and had a specific activity of 5.33 μmol/min/mg at 50°C, which was 54-fold higher than that of the parent DAADH. In addition, the specific activities of the mutant toward d-leucine, d-norleucine, d-methionine, d-isoleucine, and d-tryptophan were much higher (6 to 25 times) than those of the parent enzyme. For reductive amination, the D94A mutant exhibited extremely high specific activity with phenylpyruvate (16.1 μmol/min/mg at 50°C). The structures of the D94A-Y224F double mutant in complex with NADP + and in complex with both NADPH and 2-keto-6-aminocapronic acid (lysine oxo-analogue) were then determined at resolutions of 1.59 Å and 1.74 Å, respectively. The phenylpyruvate-binding model suggests that the D94A mutation prevents the substrate phenyl group from sterically clashing with the side chain of Asp94. A structural comparison suggests that both the enlarged substrate-binding pocket and enhanced hydrophobicity of the pocket are mainly responsible for the high reactivity of the D94A mutant toward the hydrophobic d-amino acids with bulky side chains. IMPORTANCE In recent years, the potential uses for d-amino acids as source materials for the industrial production of medicines, seasonings, and agrochemicals have been growing. To date, several methods have been used for the production of d-amino acids, but all include tedious steps. The use of NAD(P) + -dependent d-amino acid dehydrogenase (DAADH) makes single-step production of d-amino acids from oxo-acid analogs and ammonia possible. We recently succeeded in creating a stable DAADH and demonstrated that it is applicable for one-step synthesis of d-amino acids, such as d-leucine and d-isoleucine. As the next step, the creation of an enzyme exhibiting different substrate specificity and higher catalytic efficiency is a key to the further development of d-amino acid production. In this study, we succeeded in creating a novel mutant exhibiting extremely high catalytic activity for phenylpyruvate amination. Structural insight into the mutant will be useful for further improvement of DAADHs. Copyright © 2017 American Society for Microbiology.

Structure-Based Engineering of an Artificially Generated NADP+-Dependent d-Amino Acid Dehydrogenase

PubMed Central

Hayashi, Junji; Seto, Tomonari; Akita, Hironaga; Watanabe, Masahiro; Hoshino, Tamotsu; Yoneda, Kazunari; Ohshima, Toshihisa

2017-01-01

ABSTRACT A stable NADP+-dependent d-amino acid dehydrogenase (DAADH) was recently created from Ureibacillus thermosphaericus meso-diaminopimelate dehydrogenase through site-directed mutagenesis. To produce a novel DAADH mutant with different substrate specificity, the crystal structure of apo-DAADH was determined at a resolution of 1.78 Å, and the amino acid residues responsible for the substrate specificity were evaluated using additional site-directed mutagenesis. By introducing a single D94A mutation, the enzyme's substrate specificity was dramatically altered; the mutant utilized d-phenylalanine as the most preferable substrate for oxidative deamination and had a specific activity of 5.33 μmol/min/mg at 50°C, which was 54-fold higher than that of the parent DAADH. In addition, the specific activities of the mutant toward d-leucine, d-norleucine, d-methionine, d-isoleucine, and d-tryptophan were much higher (6 to 25 times) than those of the parent enzyme. For reductive amination, the D94A mutant exhibited extremely high specific activity with phenylpyruvate (16.1 μmol/min/mg at 50°C). The structures of the D94A-Y224F double mutant in complex with NADP+ and in complex with both NADPH and 2-keto-6-aminocapronic acid (lysine oxo-analogue) were then determined at resolutions of 1.59 Å and 1.74 Å, respectively. The phenylpyruvate-binding model suggests that the D94A mutation prevents the substrate phenyl group from sterically clashing with the side chain of Asp94. A structural comparison suggests that both the enlarged substrate-binding pocket and enhanced hydrophobicity of the pocket are mainly responsible for the high reactivity of the D94A mutant toward the hydrophobic d-amino acids with bulky side chains. IMPORTANCE In recent years, the potential uses for d-amino acids as source materials for the industrial production of medicines, seasonings, and agrochemicals have been growing. To date, several methods have been used for the production of d-amino acids, but all include tedious steps. The use of NAD(P)+-dependent d-amino acid dehydrogenase (DAADH) makes single-step production of d-amino acids from oxo-acid analogs and ammonia possible. We recently succeeded in creating a stable DAADH and demonstrated that it is applicable for one-step synthesis of d-amino acids, such as d-leucine and d-isoleucine. As the next step, the creation of an enzyme exhibiting different substrate specificity and higher catalytic efficiency is a key to the further development of d-amino acid production. In this study, we succeeded in creating a novel mutant exhibiting extremely high catalytic activity for phenylpyruvate amination. Structural insight into the mutant will be useful for further improvement of DAADHs. PMID:28363957

Adduct formation of ionic and nanoparticular silver with amino acids and glutathione

NASA Astrophysics Data System (ADS)

Blaske, Franziska; Stork, Lisa; Sperling, Michael; Karst, Uwe

2013-09-01

To investigate the interaction of ionic and nanoparticular silver with amino acids and small peptides, an electrospray ionization time-of-flight mass spectrometry method was developed. Monomeric and oligomeric silver adducts were formed with amino acids including cysteine (Cys), methionine, histidine, lysine, or the tripeptide glutathione (GSH). The obtained spectra for ionic silver show clusters in different ratios between Ag+ and the reaction partners (X) including [Ag n X m - ( n + 1)H]- ( n = 1-4, m = 1-3). Regarding Cys, adduct clusters up to n = 5 and m = 4 were observed as well. Considering silver-GSH interactions, even doubly charged oligomers occur generating [Ag( a + 1)GSH a - ( a + 3)H]2- ( a = 5-7) and [Ag b GSH b - ( b + 2)H]2- ( b = 4-8) ions. 1H NMR data of free GSH compared to that after treatment with Ag+ confirm sulfur-metal interactions due to changing chemical shifts for the protons located adjacent to the thiol group. Density functional theory calculations for silver-GSH clusters may explain the formation of experimentally recorded large clusters due to cooperative effects between silver and carboxylic acid side chains. Both sets of experiments indicate the presence of these adducts in the liquid phase. For silver nanoparticles, the respective data confirm the release of silver ions and the subsequent adduct formation.

Role of Nitrogen and Carbon Transport, Regulation, and Metabolism Genes for Saccharomyces cerevisiae Survival In Vivo†

PubMed Central

Kingsbury, Joanne M.; Goldstein, Alan L.; McCusker, John H.

2006-01-01

Saccharomyces cerevisiae is both an emerging opportunistic pathogen and a close relative of pathogenic Candida species. To better understand the ecology of fungal infection, we investigated the importance of pathways involved in uptake, metabolism, and biosynthesis of nitrogen and carbon compounds for survival of a clinical S. cerevisiae strain in a murine host. Potential nitrogen sources in vivo include ammonium, urea, and amino acids, while potential carbon sources include glucose, lactate, pyruvate, and fatty acids. Using mutants unable to either transport or utilize these compounds, we demonstrated that no individual nitrogen source was essential, while glucose was the most significant primary carbon source for yeast survival in vivo. Hydrolysis of the storage carbohydrate glycogen made a slight contribution for in vivo survival compared with a substantial requirement for trehalose hydrolysis. The ability to sense and respond to low glucose concentrations was also important for survival. In contrast, there was little or no requirement in vivo in this assay for any of the nitrogen-sensing pathways, nitrogen catabolite repression, the ammonium- or amino acid-sensing pathways, or general control. By using auxotrophic mutants, we found that some nitrogenous compounds (polyamines, methionine, and lysine) can be acquired from the host, while others (threonine, aromatic amino acids, isoleucine, and valine) must be synthesized by the pathogen. Our studies provide insights into the yeast-host environment interaction and identify potential antifungal drug targets. PMID:16682459

A novel collagen hydrogel cross-linked by gamma-ray irradiation in acidic pH conditions.

PubMed

Inoue, Naoki; Bessho, Masahiko; Furuta, Masakazu; Kojima, Takao; Okuda, Shuichi; Hara, Masayuki

2006-01-01

We made a new type of collagen gel by gamma-ray irradiation of an acidic solution of type-I collagen, and performed comparative studies on a conventional gel and the new type of gel. The neutral gel, a conventional 0.3% (w/v) collagen gel, was formed at neutral pH and then irradiated by gamma-rays. The acidic gel, a 0.3% (w/v) collagen gel, was formed directly from the acidic solution of collagen by y-ray irradiation. Both types of gel were prepared, swollen in water and then dried for the measurement of specific water content. The neutral gel showed a relatively high specific water content and shrunk moderately, depending on the dose, while the acidic gel showed lower specific water content and shrunk clearly by y-ray irradiation. A three-dimensional tangled network of microfibrils was clearly observed in the neutral gels by scanning electron microscopy, but not in the acidic gels. From these results, we concluded that the acidic gel was quite different from a conventional collagen gel. Sodium dodecylsulfate-polyacrylamide gel electrophoresis showed that the alpha1 subunit and alpha2 subunit of the collagen molecule were cross-linked. The triple-helical structure of collagen was only partially perturbed, but not denatured completely, because the circular dichroism spectrum of the collagen solution irradiated at 1.3 kGy was similar to that of native collagen solution. Amino-acid analysis revealed that tyrosine, phenylalanine and histidine decreased by irradiation in the neutral gel. In the case of the acidic gel, these three amino acids and methionine decreased. We considered that these amino acids were cross-linking points between the collagen subunits during the gamma-ray irradiation.

Methionine and serine synergistically suppress hyperhomocysteinemia induced by choline deficiency, but not by guanidinoacetic acid, in rats fed a low casein diet.

PubMed

Liu, Yi-qun; Liu, Ying; Morita, Tatsuya; Sugiyama, Kimio

2011-01-01

The effects of dietary supplementation with 0.5% methionine, 2.5% serine, or both on hyperhomocysteinemia induced by deprivation of dietary choline or by dietary addition of 0.5% guanidinoacetic acid (GAA) were investigated in rats fed a 10% casein diet. Hyperhomocysteinemia induced by choline deprivation was not suppressed by methionine alone and was only partially suppressed by serine alone, whereas it was completely suppressed by a combination of methionine and serine, suggesting a synergistic effect of methionine and serine. Fatty liver was also completely prevented by the combination of methionine and serine. Compared with methionine alone, the combination of methionine and serine decreased hepatic S-adenosylhomocysteine and homocysteine concentrations and increased hepatic betaine and serine concentrations and betaine-homocysteine S-methyltransferase activity. GAA-induced hyperhomocysteinemia was partially suppressed by methionine alone, but no interacting effect of methionine and serine was detected. In contrast, GAA-induced fatty liver was completely prevented by the combination of methionine and serine. These results indicate that a combination of methionine and serine is effective in suppressing both hyperhomocysteinemia and fatty liver induced by choline deprivation, and that methionine alone is effective in suppressing GAA-induced hyperhomocysteinemia partially.

Some nutritional aspects of reproduction in prairie nesting pintails

USGS Publications Warehouse

Krapu, G.L.; Swanson, G.A.

1975-01-01

The nutritional significance of invertebrate foods in the diet of breeding hen waterfowl during the period of egg formation is discussed. Proximate, elemental, and amino acid analyses of the principal foods consumed by hen pintails (Anas acuta) during the nesting season indicate the animal foods selected are rich sources of protein and calcium, whereas plant foods tested were low in protein, particularly in the essential amino acids lysine and methionine. Calcium content in major plant foods was far below needs considered adequate for egg production. Studies with penned, hand-reared pintails indicated the inadequacy of wheat as the dietary staple during breeding. Egg production among pairs on the control diet differed significantly from that of the wheat plus oystershell (P < 0.05) and wheat (P < 0.01) diets. Pairs fed wheat during the breeding period experienced nearly complete reproductive failure. The poor reproductive response among hens on the diet of wheat plus oystershell suggested that calcium availability was not the only factor limiting productivity.

[The primary structure of the alpha-amylase inhibitor Hoe 467A from Streptomyces tendae 4158. A new class of inhibitors].

PubMed

Aschauer, H; Vértesy, L; Nesemann, G; Braunitzer, G

1983-10-01

The native or modified alpha-amylase inhibitor Hoe 467A - isolated from the culture medium of Streptomyces tendae 4158 - and overlapping peptides were degraded by the automatic Edman technique. The oxidized or aminoethylated or oxidized and maleoylated inhibitor was digested with trypsin and the native inhibitor with pepsin. Further digestion with Staphylococcus aureus proteinase was also carried out. After peptic digestion two cystin peptides were isolated, which allowed the establishment of the disulfide bonds. The alpha-amylase inhibitor is a polypeptid consisting of 74 amino-acid residues with a molecular mass of 7958 Da. The inhibitor is composed of all naturally occurring amino acids except methionine and phenylalanine and shows no sequence homology to known inhibitors. The clinical and pharmacological importance in respect to the inhibitors ability for inactivation of human salivary and pancreatic alpha-amylase is discussed. Especially the proteinase resistance of the inhibitor enables a clinical application in human (e.g. Diabetes mellitus) per os.

Evaluating two-dimensional electrophoresis profiles of the protein phaseolin as markers of genetic differentiation and seed protein quality in common bean (Phaseolus vulgaris L.).

PubMed

López-Pedrouso, María; Bernal, Javier; Franco, Daniel; Zapata, Carlos

2014-07-23

High-resolution two-dimensional electrophoresis (2-DE) profiles of the protein phaseolin, the major seed storage protein of common bean, display great number of spots with differentially glycosylated and phosphorylated α- and β-type polypeptides. This work aims to test whether these complex profiles can be useful markers of genetic differentiation and seed protein quality in bean populations. The 2-DE phaseolin profile and the amino acid composition were examined in bean seeds from 18 domesticated and wild accessions belonging to the Mesoamerican and Andean gene pools. We found that proteomic distances based on 2-DE profiles were successful in identifying the accessions belonging to each gene pool and outliers distantly related. In addition, accessions identified as outliers from proteomic distances showed the highest levels of methionine content, an essential amino acid deficient in bean seeds. These findings suggest that 2-DE phaseolin profiles provide valuable information with potential of being used in common bean genetic improvement.

Interaction of bombesin and its fragments with gold nanoparticles analyzed using surface-enhanced Raman spectroscopy

NASA Astrophysics Data System (ADS)

Tąta, Agnieszka; Szkudlarek, Aleksandra; Kim, Younkyoo; Proniewicz, Edyta

2017-02-01

This work demonstrates the application of commercially available stable surface composed of gold nanograins with diameters ranging from 70 to 226 nm deposited onto silicon wafer for surface-enhanced Raman scattering investigations of biologically active compounds, such as bombesin (BN) and its fragments. BN is an important neurotransmitter involved in a complex signaling pathways and biological responses; for instance, hypertensive action, contractive on uterus, colon or ileum, locomotor activity, stimulation of gastric and insulin secretion as well as growth promotion of various tumor cell lines, including: lung, prostate, stomach, colon, and breast. It has also been shown that 8-14 BN C-terminal fragment partially retains the biological activity of BN. The SERS results for BN and its fragment demonstrated that (1) three amino acids from these peptides sequence; i.e., L-histidine, L-methionine, and L-tryptophan, are involved in the interaction with gold coated silicon wafer and (2) the strength of these interactions depends upon the aforementioned amino acids position in the peptide sequence.

Loss of conformational stability in calmodulin upon methionine oxidation.

PubMed Central

Gao, J; Yin, D H; Yao, Y; Sun, H; Qin, Z; Schöneich, C; Williams, T D; Squier, T C

1998-01-01

We have used electrospray ionization mass spectrometry (ESI-MS), circular dichroism (CD), and fluorescence spectroscopy to investigate the secondary and tertiary structural consequences that result from oxidative modification of methionine residues in wheat germ calmodulin (CaM), and prevent activation of the plasma membrane Ca-ATPase. Using ESI-MS, we have measured rates of modification and molecular mass distributions of oxidatively modified CaM species (CaMox) resulting from exposure to H2O2. From these rates, we find that oxidative modification of methionine to the corresponding methionine sulfoxide does not predispose CaM to further oxidative modification. These results indicate that methionine oxidation results in no large-scale alterations in the tertiary structure of CaMox, because the rates of oxidative modification of individual methionines are directly related to their solvent exposure. Likewise, CD measurements indicate that methionine oxidation results in little change in the apparent alpha-helical content at 28 degrees C, and only a small (0.3 +/- 0.1 kcal mol(-1)) decrease in thermal stability, suggesting the disruption of a limited number of specific noncovalent interactions. Fluorescence lifetime, anisotropy, and quenching measurements of N-(1-pyrenyl)-maleimide (PMal) covalently bound to Cys26 indicate local structural changes around PMal in the amino-terminal domain in response to oxidative modification of methionine residues in the carboxyl-terminal domain. Because the opposing globular domains remain spatially distant in both native and oxidatively modified CaM, the oxidative modification of methionines in the carboxyl-terminal domain are suggested to modify the conformation of the amino-terminal domain through alterations in the structural features involving the interdomain central helix. The structural basis for the linkage between oxidative modification and these global conformational changes is discussed in terms of possible alterations in specific noncovalent interactions that have previously been suggested to stabilize the central helix in CaM. PMID:9512014

Dietary supplementation of branched-chain amino acids increases muscle net amino acid fluxes through elevating their substrate availability and intramuscular catabolism in young pigs.

PubMed

Zheng, Liufeng; Zuo, Fangrui; Zhao, Shengjun; He, Pingli; Wei, Hongkui; Xiang, Quanhang; Pang, Jiaman; Peng, Jian

2017-04-01

Branched-chain amino acids (BCAA) have been clearly demonstrated to have anabolic effects on muscle protein synthesis. However, little is known about their roles in the regulation of net AA fluxes across skeletal muscle in vivo. This study was aimed to investigate the effect and related mechanisms of dietary supplementation of BCAA on muscle net amino acid (AA) fluxes using the hindlimb flux model. In all fourteen 4-week-old barrows were fed reduced-protein diets with or without supplemental BCAA for 28 d. Pigs were implanted with carotid arterial, femoral arterial and venous catheters, and fed once hourly with intraarterial infusion of p-amino hippurate. Arterial and venous plasma and muscle samples were obtained for the measurement of AA, branched-chain α-keto acids (BCKA) and 3-methylhistidine (3-MH). Metabolomes of venous plasma were determined by HPLC-quadrupole time-of-flight-MS. BCAA-supplemented group showed elevated muscle net fluxes of total essential AA, non-essential AA and AA. As for individual AA, muscle net fluxes of each BCAA and their metabolites (alanine, glutamate and glutamine), along with those of histidine, methionine and several functional non-essential AA (glycine, proline and serine), were increased by BCAA supplementation. The elevated muscle net AA fluxes were associated with the increase in arterial and intramuscular concentrations of BCAA and venous metabolites including BCKA and free fatty acids, and were also related to the decrease in the intramuscular concentration of 3-MH. Correlation analysis indicated that muscle net AA fluxes are highly and positively correlated with arterial BCAA concentrations and muscle net BCKA production. In conclusion, supplementing BCAA to reduced-protein diet increases the arterial concentrations and intramuscular catabolism of BCAA, both of which would contribute to an increase of muscle net AA fluxes in young pigs.

Hydrolysis of proteins with methanesulfonic acid for improved HPLC-ICP-MS determination of seleno-methionine in yeast and nuts.

PubMed

Wrobel, Katarzyna; Kannamkumarath, Sasi S; Wrobel, Kazimierz; Caruso, Joseph A

2003-01-01

In this work, the use of methanesulfonic acid for protein hydrolysis is proposed for evaluation of Se-methionine in yeast, Brazil nuts, and possibly other selenium-rich biological samples. The hydrolysis was carried out by heating the sample with 4 mol L(-1) acid at reflux for 8 h. Two chromatographic techniques (size-exclusion and ion-pairing) coupled with ICP-MS detection were used to compare the release of Se-methionine from proteins by enzymatic (proteinase K, protease XIV) and acid hydrolyses. A more efficient liberation of Se-methionine was observed by acid hydrolysis. For quantification, the sample extracts were introduced onto a C8 Alltima column, and the separation was achieved with a mobile phase containing 5 mmol L(-1) hexanesulfonic acid in citrate buffer (pH 4.5)/methanol (95:5). The results obtained by standard addition showed 816+/-17 micro g g(-1) and 36.2+/-1.5 micro g g(-1) of selenium in the form of Se-methionine in yeast and nuts, respectively (65% and 75% of total selenium).

Drought Tolerance in Pinus halepensis Seed Sources As Identified by Distinctive Physiological and Molecular Markers

PubMed Central

Taïbi, Khaled; del Campo, Antonio D.; Vilagrosa, Alberto; Bellés, José M.; López-Gresa, María Pilar; Pla, Davinia; Calvete, Juan J.; López-Nicolás, José M.; Mulet, José M.

2017-01-01

Drought is one of the main constraints determining forest species growth, survival and productivity, and therefore one of the main limitations for reforestation or afforestation. The aim of this study is to characterize the drought response at the physiological and molecular level of different Pinus halepensis (common name Aleppo pine) seed sources, previously characterized in field trials as drought-sensitive or drought-tolerant. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. Gas-exchange, water potential, photosynthetic pigments, soluble sugars, free amino acids, glutathione and proteomic analyses were carried out on control and drought-stressed seedlings in greenhouse conditions. Gas-exchange determinations were also assessed in field-planted seedlings in order to validate the greenhouse experimental conditions. Drought-tolerant seed sources presented higher values of photosynthetic rates, water use efficiency, photosynthetic pigments and soluble carbohydrates concentrations. We observed the same pattern of variation of photosynthesis rate and maximal efficiency of PSII in field. Interestingly drought-tolerant seed sources exhibited increased levels of glutathione, methionine and cysteine. The proteomic profile of drought tolerant seedlings identified two heat shock proteins and an enzyme related to methionine biosynthesis that were not present in drought sensitive seedlings, pointing to the synthesis of sulfur amino acids as a limiting factor for drought tolerance in Pinus halepensis. Our results established physiological and molecular traits useful as distinctive markers to predict drought tolerance in Pinus halepensis provenances that could be reliably used in reforestation programs in drought prone areas. PMID:28791030

Drought Tolerance in Pinus halepensis Seed Sources As Identified by Distinctive Physiological and Molecular Markers.

PubMed

Taïbi, Khaled; Del Campo, Antonio D; Vilagrosa, Alberto; Bellés, José M; López-Gresa, María Pilar; Pla, Davinia; Calvete, Juan J; López-Nicolás, José M; Mulet, José M

2017-01-01

Drought is one of the main constraints determining forest species growth, survival and productivity, and therefore one of the main limitations for reforestation or afforestation. The aim of this study is to characterize the drought response at the physiological and molecular level of different Pinus halepensis (common name Aleppo pine) seed sources, previously characterized in field trials as drought-sensitive or drought-tolerant. This approach aims to identify different traits capable of predicting the ability of formerly uncharacterized seedlings to cope with drought stress. Gas-exchange, water potential, photosynthetic pigments, soluble sugars, free amino acids, glutathione and proteomic analyses were carried out on control and drought-stressed seedlings in greenhouse conditions. Gas-exchange determinations were also assessed in field-planted seedlings in order to validate the greenhouse experimental conditions. Drought-tolerant seed sources presented higher values of photosynthetic rates, water use efficiency, photosynthetic pigments and soluble carbohydrates concentrations. We observed the same pattern of variation of photosynthesis rate and maximal efficiency of PSII in field. Interestingly drought-tolerant seed sources exhibited increased levels of glutathione, methionine and cysteine. The proteomic profile of drought tolerant seedlings identified two heat shock proteins and an enzyme related to methionine biosynthesis that were not present in drought sensitive seedlings, pointing to the synthesis of sulfur amino acids as a limiting factor for drought tolerance in Pinus halepensis . Our results established physiological and molecular traits useful as distinctive markers to predict drought tolerance in Pinus halepensis provenances that could be reliably used in reforestation programs in drought prone areas.

Sulfur Radical-Induced Redox Modifications in Proteins: Analysis and Mechanistic Aspects.

PubMed

Schöneich, Christian

2017-03-10

The sulfur-containing amino acids cysteine (Cys) and methionine (Met) are prominent protein targets of redox modification during conditions of oxidative stress. Here, two-electron pathways have received widespread attention, in part due to their role in signaling processes. However, Cys and Met are equally prone to one-electron pathways, generating intermediary radicals and/or radial ions. These radicals/radical ions can generate various reaction products that are not commonly monitored in redox proteomic studies, but they may be relevant for the fate of proteins during oxidative stress. Recent Advances: Time-resolved kinetic studies and product analysis have expanded our mechanistic understanding of radical reaction pathways of sulfur-containing amino acids. These reactions are now studied in some detail for Met and Cys in proteins, and homocysteine (Hcy) chemically linked to proteins, and the role of protein radical reactions in physiological processes is evolving. Radical-derived products from Cys, Hcy, and Met can react with additional amino acids in proteins, leading to secondary protein modifications, which are potentially remote from initial points of radical attack. These products may contain intra- and intermolecular cross-links, which may lead to protein aggregation. Protein sequence and conformation will have a significant impact on the formation of such products, and a thorough understanding of reaction mechanisms and specifically how protein structure influences reaction pathways will be critical for identification and characterization of novel reaction products. Future studies must evaluate the biological significance of novel reaction products that are derived from radical reactions of sulfur-containing amino acids. Antioxid. Redox Signal. 26, 388-405.

Amino Acid Profiling of Zinc Resistant Prostate Cancer Cell Lines: Associations With Cancer Progression.

PubMed

Kratochvilova, Monika; Raudenska, Martina; Heger, Zbynek; Richtera, Lukas; Cernei, Natalia; Adam, Vojtech; Babula, Petr; Novakova, Marie; Masarik, Michal; Gumulec, Jaromir

2017-05-01

Failure in intracellular zinc accumulation is a key process in prostate carcinogenesis. Nevertheless, epidemiological studies of zinc administration have provided contradicting results. In order to examine the impact of the artificial intracellular increase of zinc(II) ions on prostate cancer metabolism, PNT1A, 22Rv1, and PC-3 prostatic cell lines-depicting different stages of cancer progression-and their zinc-resistant counterparts were used. To determine "benign" and "malignant" metabolic profiles, amino acid patterns, gene expression, and antioxidant capacity of these cell lines were assessed. Amino acid profiles were examined using an ion-exchange liquid chromatography. Intracellular zinc content was measured by atomic absorption spectrometry. Metallothionein was quantified using differential pulse voltammetry. The content of reduced glutathione was determined using high performance liquid chromatography coupled with an electrochemical detector. Cellular antioxidant capacity was determined by the ABTS test and gene expression analysis was performed by qRT-PCR. Long-term zinc treatment was shown to reroute cell metabolism from benign to more malignant type. Long-term application of high concentration of zinc(II) significantly enhanced cisplatin resistance, invasiveness, cellular antioxidant capacity, synthesis of glutathione, and expression of treatment resistance- and stemness-associated genes (SOX2, POU5F1, BIRC5). Tumorous cell lines universally displayed high accumulation of aspartate and sarcosine and depletion of essential amino acids. Increased aspartate/threonine, aspartate/methionine, and sarcosine/serine ratios were associated with cancer phenotype with high levels of sensitivity and specificity. Prostate 77: 604-616, 2017. © 2017 Wiley Periodicals, Inc. © 2017 Wiley Periodicals, Inc.

Plasma glutathione of HIV⁺ patients responded positively and differently to dietary supplementation with cysteine or glutamine.

PubMed

Borges-Santos, Maria Dorotéia; Moreto, Fernando; Pereira, Paulo Câmara Marques; Ming-Yu, Yong; Burini, Roberto Carlos

2012-07-01

Patients with positivity for the human immunodeficiency virus (HIV⁺) present low concentrations of antioxidant nutrients, including total glutathione (GSH) and its precursors. We investigated the responses of the sulfur-containing amino acid pathway to cysteine and glutamine (Gln) dietary supplements in patients with HIV⁺ compared with healthy controls. Twelve treated patients (six men and six women, 22-45 y old) and 20 healthy controls (10 men and 10 women, 20-59 y old) were randomly assigned to 7-d dietary supplements containing N-acetylcysteine (NAC; 1 g/d) or Gln (20 g/d), with a 7-d washout period ingesting their usual diet. Blood samples were drawn after an overnight fast. High-performance liquid chromatographic plasma analysis of sulfur-containing amino acids (methionine, homocysteine, cysteine, and taurine), GSH, oxidized GSH, and serine, glycine, glutamic acid, and Gln was carried out moments before and after 7-d supplementations. Statistical comparisons were undertaken between groups and between dietary supplements (P < 0.05). Patients with HIV⁺ showed higher oxidized GSH and lower concentrations of GSH and all amino acids except homocysteine. The HIV⁺ group responded to the NAC by increased levels of sulfur-containing amino acids and GSH and equalized taurine and GSH levels in the control group. The Gln supplements also equalized the levels of GSH, Gln, and glycine in the control group. An increase in GSH may be attained by NAC or Gln supplementation, with NAC acting by increasing cysteine levels and Gln likely acting by replenishing the glycine pool (trial registered at http://www.clinicaltrials.gov, identifier NCT00910442). Copyright © 2012 Elsevier Inc. All rights reserved.

Amino acid changes during transition to a vegan diet supplemented with fish in healthy humans.

PubMed

Elshorbagy, Amany; Jernerén, Fredrik; Basta, Marianne; Basta, Caroline; Turner, Cheryl; Khaled, Maram; Refsum, Helga

2017-08-01

To explore whether changes in dietary protein sources can lower plasma branched-chain amino acids (BCAAs), aromatic amino acids and sulfur amino acids (SAAs) that are often elevated in the obese, insulin-resistant state and in type 2 diabetes. Thirty-six subjects (mean age 31 ± 2 years) underwent a voluntary abstinence from meat, poultry, eggs, and dairy products for 6 weeks, while enriching the diet with fish, in fulfillment of a religious fast. Subjects were assessed 1 week before the fast (V1), 1 week after initiation of the fast (V2) and in the last week of the fast (V3). Thirty-four subjects completed all three visits. Fasting plasma BCAAs decreased at V2 and remained low at V3 (P < 0.001 for all). Valine showed the greatest decline, by 20 and 19 % at V2 and V3, respectively. Phenylalanine and tryptophan, but not tyrosine, also decreased at V2 and V3. The two proteinogenic SAAs, methionine and cysteine, remained stable, but the cysteine product, taurine, decreased from 92 ± 7 μmol/L to 66 ± 6 (V2; P = 0.003) and 65 ± 6 μmol/L (V3; P = 0.003). A progressive decline in plasma glutamic acid, coupled with an increase in glutamine, was observed. Plasma total and LDL cholesterol decreased at V2 and V3 (P < 0.001 for all). Changing dietary protein sources to plant- and fish-based sources in an ad libitum setting lowers the plasma BCAAs that have been linked to diabetes risk. These findings point to habitual diet as a potentially modifiable determinant of fasting plasma BCAA concentrations.

Insecticidal components from field pea extracts: sequences of some variants of pea albumin 1b.

PubMed

Taylor, Wesley G; Sutherland, Daniel H; Olson, Douglas J H; Ross, Andrew R S; Fields, Paul G

2004-12-15

Methanol soluble insecticidal peptides with masses of 3752, 3757, and 3805 Da, isolated from crude extracts (C8 extracts) derived from the protein-enriched flour of commercial field peas [Pisum sativum (L.)], were purified by reversed phase chromatography and, after reduction and alkylation, were sequenced by matrix-assisted laser desorption/ionization (MALDI) time-of-flight mass spectrometry with the aid of various peptidases. These major peptides were variants of pea albumin 1b (PA1b) with methionine sulfoxide rather than methionine at position 12. Peptide 3752 showed additional variations at positions 29 (valine for isoleucine) and 34 (histidine for asparagine). A minor, 37 amino acid peptide with a molecular mass of 3788 Da was also sequenced and differed from a known PA1b variant at positions 1, 25, and 31. Sequence variants of PA1b with their molecular masses were compiled, and variants that matched the accurate masses of the experimental peptides were used to narrow the search. MALDI postsource decay experiments on pronase fragments helped to confirm the sequences. Whole and dehulled field peas gave insecticidal C8 extracts in the laboratory that were enriched in peptides with masses of 3736, 3741, and 3789 Da, as determined by high-performance liquid chromatography (HPLC) and electrospray ionization mass spectrometry. It was therefore concluded that oxidation of the methionine residues to methionine sulfoxide occurred primarily during the processing of dehulled peas in a mill.

Effects of proteome rebalancing and sulfur nutrition on the accumulation of methionine rich δ-zein in transgenic soybeans

PubMed Central

Kim, Won-Seok; Jez, Joseph M.; Krishnan, Hari B.

2014-01-01

Expression of heterologous methionine-rich proteins to increase the overall sulfur amino acid content of soybean seeds has been only marginally successful, presumably due to low accumulation of transgenes in soybeans or due to gene silencing. Proteome rebalancing of seed proteins has been shown to promote the accumulation of foreign proteins. In this study, we have utilized RNAi technology to suppress the expression of the β-conglycinin, the abundant 7S seed storage proteins of soybean. Western blot and 2D-gel analysis revealed that β-conglycinin knockdown line (SAM) failed to accumulate the α′, α, and β-subunits of β-conglycinin. The proteome rebalanced SAM retained the overall protein and oil content similar to that of wild-type soybean. We also generated transgenic soybean lines expressing methionine-rich 11 kDa δ-zein under the control of either the glycinin or β-conglycinin promoter. The introgression of the 11 kDa δ-zein into β-conglycinin knockdown line did not enhance the accumulation of the 11 kDa δ-zein. However, when the same plants were grown in sulfur-rich medium, we observed 3- to 16-fold increased accumulation of the 11 kDa δ-zein. Transmission electron microscopy observation revealed that seeds grown in sulfur-rich medium contained numerous endoplasmic reticulum derived protein bodies. Our findings suggest that sulfur availability, not proteome rebalancing, is needed for high-level accumulation of heterologous methionine-rich proteins in soybean seeds. PMID:25426134

Rumen escape of methionine and lysine administered intraruminally to growing double-muscled Belgian Blue bulls.

PubMed

Froidmont, Eric; Rondia, Pierre; Théwis, André; Beckers, Yves

2002-01-01

In many dietary conditions, methionine (Met) and lysine (Lys) are the most limiting amino acids (AA) for ruminants. The AA protected from ruminal fermentation are not commercially available, with the exception of Met which is not always economical, especially for meat production. This study measured ruminal escape of free Met and Lys supplemented intraruminally to fast growing bulls. Six double-muscled Belgian Blue bulls, fed a high concentrate diet and fitted with a rumen cannula, received free Met (40 g x d(-1)) and free Lys (60 g x d(-1)), individually or simultaneously, in a duplicated Latin square design. The mean ruminal escape of Met and Lys reached 37 and 45% respectively, and did not differ if administered separately or together. Plasma Lys and Met concentrations were increased by 504 and 126%, respectively. Substantial proportions of free AA escaped ruminal fermentation and were available for absorption from the small intestine when they were administered at physiologically high levels.

Amino acid substitutions enhancing thermostability of Bacillus polymyxa beta-glucosidase A.

PubMed Central

Lopez-Camacho, C; Salgado, J; Lequerica, J L; Madarro, A; Ballestar, E; Franco, L; Polaina, J

1996-01-01

Mutations enhancing the thermostability of beta-glucosidase A of Bacillus polymyxa, a family 1 glycosyl hydrolase, have been obtained after hydroxylamine mutagenesis of a plasmid containing the bglA gene, transformation of Escherichia coli with the mutagenized plasmid, and identification of transformant colonies that showed beta-glucosidase activity after a thermal treatment that inactivated the wild-type enzyme. Two additive mutations have been characterized that cause replacement of glutamate at position 96 by lysine and of methionine at position 416 by isoleucine respectively. The thermoresistant mutant enzymes showed increased resistance to other denaturing agents, such as pH and urea, while their kinetic parameters did not change. CD spectra indicated that the E96K replacement caused an increase in alpha-helix content. The observed effect of the M416I mutation is consistent with the lower content of cysteine and methionine found in family 1 enzymes of thermophilic species compared with similar ones from mesophilic organisms. PMID:8615777

Reduction of nitrogen excretion and emission in poultry: A review for organic poultry.

PubMed

Chalova, Vesela I; Kim, Jihyuk; Patterson, Paul H; Ricke, Steven C; Kim, Woo K

2016-01-01

Organic poultry is an alternative to conventional poultry which is rapidly developing as a response to customers' demand for better food and a cleaner environment. Although organic poultry manure can partially be utilized by organic horticultural producers, litter accumulation as well as excessive nitrogen still remains a challenge to maintain environment pureness, animal, and human health. Compared to conventional poultry, diet formulation without nitrogen overloading in organic poultry is even more complicated due to specific standards and regulations which limit the application of some supplements and imposes specific criteria to the ingredients in use. This is especially valid for methionine provision which supplementation as a crystalline form is only temporarily allowed. This review is focused on the utilization of various protein sources in the preparation of a diet composed of 100% organic ingredients which meet the avian physiology need for methionine, while avoiding protein overload. The potential to use unconventional protein sources such as invertebrates and microbial proteins to achieve optimal amino acid provision is also discussed.

Effect of Dioxygen on Copper(II) Binding to α-Synuclein

PubMed Central

Lucas, Heather R.; Lee, Jennifer C.

2010-01-01

Using the fluorescent amino acid tryptophan (Trp), we have characterized the copper(II) binding of F4W α-synuclein in the presence and absence of dioxygen at neutral pH. Variations in Trp fluorescence indicate that copper(II) binding is enhanced by the presence of dioxygen, with the apparent dissociation constant (Kd(app)) changing from 100 nM (anaerobic) to 10 nM (aerobic). To investigate the possible role of methionine oxidation, complementary work focused on synthetic peptide models of the N-terminal Cu(II)-α-syn site, MDV(F/W) and M*DV(F/W), where M*= methionine sulfoxide. Furthermore, we employed circular dichroism (CD) spectroscopy to demonstrate that the phenyl-to-indole (F→W) substitution does not alter copper(II) binding properties and to confirm the 1:1 metal-peptide binding stoichiometry. CD comparisons also revealed that Met1 oxidation does not affect the copper-peptide conformation and further suggested the possible existence of a CuII-Trp/Phe (cation-π) interaction. PMID:20064662

[Blood levels of homocysteine by high pressure liquid chromatography and comparison with two other techniques].

PubMed

Ceppa, F; Drouillard, I; Chianea, D; Burnat, P; Perrier, F; Vaillant, C; El Jahiri, Y

1999-01-01

Cardio-vascular diseases are the most common cause of death in industrialized countries. A new marker has emerged among offending risk factors in the past few years: homocysteine. This sulphured amino-acid is an important intermediate in transsulphuration and remethylation reactions of methionine's metabolism. We proposed to evaluate a home made method of determination for this parameter by high performance liquid chromatography (HPLC) and to compare it to fluorescence polarization immunoassay technique (FPIA) and to gaz phase chromatography (CG-SM). This method associated with good sensibility and precision remain much less expensive than FPIA technique.

Food intake adjustments of chicks: short term reactions to deficiencies in lysine, methionine and tryptophan.

PubMed

Picard, M L; Uzu, G; Dunnington, E A; Siegel, P B

1993-09-01

1. Two experiments were conducted to compare food intake responses of broiler chicks fed diets varying in lysine, methionine, and tryptophan. Diet D was formulated to create simultaneous deficiencies of lysine, methionine, and tryptophan. Diet A matched National Research Council (1984) recommendations for broilers, and diets B and C were, respectively, 2:1 and 1:2 mixes of diets A and D. 2. Short-term food intake can provide information on the sequences of adaptation of chicks to a diet deficient in essential amino acids. 3. Chicks consumed 26% less of diet D than A during the first 24 h posthatch. When chicks fed diet A or D to 7 d of age were then fed one of 4 diets singly, within 24 h intake was lowest for chicks fed diet D. Within 48 h, food intake of diet C was more than that of diet D and less than that of diet A, while for diet B intake was more than of diet D but not different from diet A. 4. In the second experiment, chicks were fed diet A to 8 d and then diets A or D alone or given a choice of diets A and D from 8 to 20 d of age. Within 4 to 8 h, food intake of chicks fed diet D alone decreased markedly followed by partial recovery within 24 h. In a choice setting, consistent preference of Diet A over Diet D was observed within 7 h followed by stabilisation at about 65% diet A to 35% diet D. 5. Chicks fed diet D alone from 8 to 20 d of age, then placed in the same choice situation preferred diet A to D with a delay of less than one h and stabilisation at about 85%. Chicks provided a choice of diets A and D from 8 to 20 d, and then diet D alone reduced their food intake more quickly than those not given a choice initially. 6. Broiler chicks appear to react to amino acid deficiencies within a short period (hours) by adjusting their feed intake and/or selection. The response is influenced by age and prior experience.

Structural and Functional Importance of Transmembrane Domain 3 (TM3) in the Aspartate:Alanine Antiporter AspT: Topology and Function of the Residues of TM3 and Oligomerization of AspT▿

PubMed Central

Nanatani, Kei; Maloney, Peter C.; Abe, Keietsu

2009-01-01

AspT, the aspartate:alanine antiporter of Tetragenococcus halophilus, a membrane protein of 543 amino acids with 10 putative transmembrane (TM) helices, is the prototype of the aspartate:alanine exchanger (AAE) family of transporters. Because TM3 (isoleucine 64 to methionine 85) has many amino acid residues that are conserved among members of the AAE family and because TM3 contains two charged residues and four polar residues, it is thought to be located near (or to form part of) the substrate translocation pathway that includes the binding site for the substrates. To elucidate the role of TM3 in the transport process, we carried out cysteine-scanning mutagenesis. The substitutions of tyrosine 75 and serine 84 had the strongest inhibitory effects on transport (initial rates of l-aspartate transport were below 15% of the rate for cysteine-less AspT). Considerable but less-marked effects were observed upon the replacement of methionine 70, phenylalanine 71, glycine 74, arginine 76, serine 83, and methionine 85 (initial rates between 15% and 30% of the rate for cysteine-less AspT). Introduced cysteine residues at the cytoplasmic half of TM3 could be labeled with Oregon green maleimide (OGM), whereas cysteines close to the periplasmic half (residues 64 to 75) were not labeled. These results suggest that TM3 has a hydrophobic core on the periplasmic half and that hydrophilic residues on the cytoplasmic half of TM3 participate in the formation of an aqueous cavity in membranes. Furthermore, the presence of l-aspartate protected the cysteine introduced at glycine 62 against a reaction with OGM. In contrast, l-aspartate stimulated the reactivity of the cysteine introduced at proline 79 with OGM. These results demonstrate that TM3 undergoes l-aspartate-induced conformational alterations. In addition, nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses and a glutaraldehyde cross-linking assay suggest that functional AspT forms homo-oligomers as a functional unit. PMID:19181816

Structural and functional importance of transmembrane domain 3 (TM3) in the aspartate:alanine antiporter AspT: topology and function of the residues of TM3 and oligomerization of AspT.

PubMed

Nanatani, Kei; Maloney, Peter C; Abe, Keietsu

2009-04-01

AspT, the aspartate:alanine antiporter of Tetragenococcus halophilus, a membrane protein of 543 amino acids with 10 putative transmembrane (TM) helices, is the prototype of the aspartate:alanine exchanger (AAE) family of transporters. Because TM3 (isoleucine 64 to methionine 85) has many amino acid residues that are conserved among members of the AAE family and because TM3 contains two charged residues and four polar residues, it is thought to be located near (or to form part of) the substrate translocation pathway that includes the binding site for the substrates. To elucidate the role of TM3 in the transport process, we carried out cysteine-scanning mutagenesis. The substitutions of tyrosine 75 and serine 84 had the strongest inhibitory effects on transport (initial rates of l-aspartate transport were below 15% of the rate for cysteine-less AspT). Considerable but less-marked effects were observed upon the replacement of methionine 70, phenylalanine 71, glycine 74, arginine 76, serine 83, and methionine 85 (initial rates between 15% and 30% of the rate for cysteine-less AspT). Introduced cysteine residues at the cytoplasmic half of TM3 could be labeled with Oregon green maleimide (OGM), whereas cysteines close to the periplasmic half (residues 64 to 75) were not labeled. These results suggest that TM3 has a hydrophobic core on the periplasmic half and that hydrophilic residues on the cytoplasmic half of TM3 participate in the formation of an aqueous cavity in membranes. Furthermore, the presence of l-aspartate protected the cysteine introduced at glycine 62 against a reaction with OGM. In contrast, l-aspartate stimulated the reactivity of the cysteine introduced at proline 79 with OGM. These results demonstrate that TM3 undergoes l-aspartate-induced conformational alterations. In addition, nonreducing sodium dodecyl sulfate-polyacrylamide gel electrophoresis analyses and a glutaraldehyde cross-linking assay suggest that functional AspT forms homo-oligomers as a functional unit.

Alteration of organic matter during infaunal polychaete gut passage and links to sediment organic geochemistry. Part I: Amino acids

NASA Astrophysics Data System (ADS)

Woulds, Clare; Middelburg, Jack J.; Cowie, Greg L.

2012-01-01

Of the factors which control the quantity and composition of organic matter (OM) buried in marine sediments, the links between infaunal ingestion and gut passage and sediment geochemistry have received relatively little attention. This study aimed to use feeding experiments and novel isotope tracing techniques to quantify amino acid net accumulation and loss during polychaete gut passage, and to link this to patterns of selective preservation and decay in sediments. Microcosms containing either Arenicolamarina or Hediste (formerly Nereis) diversicolor were constructed from defaunated sediment and filtered estuarine water, and maintained under natural temperature and light conditions. They were fed with 13C-labelled diatoms daily for 8 days, and animals were transferred into fresh, un-labelled sediment after ∼20 days. Samples of fauna, microcosm sediment and faecal matter were collected after 8, ∼20 and ∼40 days, and analysed for their bulk isotopic signatures and 13C-labelled amino acid compositions. Bulk isotopic data showed that, consistent with their feeding modes, Hediste assimilated added 13C more quickly, and attained a higher labelling level than Arenicola. Both species retained the added 13C in their biomass even after removal from the food. A principal component analysis of 13C-labelled amino acid mole percentages showed clear differences in composition between the algae, faunal tissues, and sediment plus faecal matter. Further, the two species of polychaete showed different compositions in their tissues. The amino acids phenylalanine, valine, leucine, iso-leucine, threonine and proline showed net accumulation in polychaete tissues. Serine, methionine, lysine, aspartic and glutamic acids and tyrosine were rapidly lost through metabolism, consistent with their presence in easily digestible cell components (as opposed to cell walls which offer physical protection). All sample types (polychaete tissues, sediments and faecal matter) were enriched in labelled glycine. Possible mechanisms for this enrichment include accumulation through inclusion in tissues with long residence times, preferential preservation (i.e. selection against) during metabolism, production from other labelled amino acids during varied metabolic processes, and accumulation in refractory by-products of secondary bacterial production. Overall, similarities were observed between amino-acid decay patterns in faunated microcosms, afaunal controls, and those previously reported in marine sediments. Thus, while polychaete gut passage did produce compound-selective accumulation and losses of certain amino acids in polychaete tissues and faecal matter, the impact of polychaete gut passage on sediment organic geochemistry was difficult to deconvolve from microbial decay. Despite processing large volumes of organic matter, polychaetes may not have distinctive influence on sediment compositions, possibly because metabolic processes concerning amino acids may be broadly similar across a wide range of organisms.

The Skeletal Muscle Anabolic Response to Plant- versus Animal-Based Protein Consumption.

PubMed

van Vliet, Stephan; Burd, Nicholas A; van Loon, Luc J C

2015-09-01

Clinical and consumer market interest is increasingly directed toward the use of plant-based proteins as dietary components aimed at preserving or increasing skeletal muscle mass. However, recent evidence suggests that the ingestion of the plant-based proteins in soy and wheat results in a lower muscle protein synthetic response when compared with several animal-based proteins. The possible lower anabolic properties of plant-based protein sources may be attributed to the lower digestibility of plant-based sources, in addition to greater splanchnic extraction and subsequent urea synthesis of plant protein-derived amino acids compared with animal-based proteins. The latter may be related to the relative lack of specific essential amino acids in plant- as opposed to animal-based proteins. Furthermore, most plant proteins have a relatively low leucine content, which may further reduce their anabolic properties when compared with animal proteins. However, few studies have actually assessed the postprandial muscle protein synthetic response to the ingestion of plant proteins, with soy and wheat protein being the primary sources studied. Despite the proposed lower anabolic properties of plant vs. animal proteins, various strategies may be applied to augment the anabolic properties of plant proteins. These may include the following: 1) fortification of plant-based protein sources with the amino acids methionine, lysine, and/or leucine; 2) selective breeding of plant sources to improve amino acid profiles; 3) consumption of greater amounts of plant-based protein sources; or 4) ingesting multiple protein sources to provide a more balanced amino acid profile. However, the efficacy of such dietary strategies on postprandial muscle protein synthesis remains to be studied. Future research comparing the anabolic properties of a variety of plant-based proteins should define the preferred protein sources to be used in nutritional interventions to support skeletal muscle mass gain or maintenance in both healthy and clinical populations. © 2015 American Society for Nutrition.

Identification of amino acids conferring chain length substrate specificities on fatty alcohol-forming reductases FAR5 and FAR8 from Arabidopsis thaliana.

PubMed

Chacón, Micaëla G; Fournier, Ashley E; Tran, Frances; Dittrich-Domergue, Franziska; Pulsifer, Ian P; Domergue, Frédéric; Rowland, Owen

2013-10-18

Fatty alcohols play a variety of biological roles in all kingdoms of life. Fatty acyl reductase (FAR) enzymes catalyze the reduction of fatty acyl-coenzyme A (CoA) or fatty acyl-acyl carrier protein substrates to primary fatty alcohols. FAR enzymes have distinct substrate specificities with regard to chain length and degree of saturation. FAR5 (At3g44550) and FAR8 (At3g44560) from Arabidopsis thaliana are 85% identical at the amino acid level and are of equal length, but they possess distinct specificities for 18:0 or 16:0 acyl chain length, respectively. We used Saccharomyces cerevisiae as a heterologous expression system to assess FAR substrate specificity determinants. We identified individual amino acids that affect protein levels or 16:0-CoA versus 18:0-CoA specificity by expressing in yeast FAR5 and FAR8 domain-swap chimeras and site-specific mutants. We found that a threonine at position 347 and a serine at position 363 were important for high FAR5 and FAR8 protein accumulation in yeast and thus are likely important for protein folding and stability. Amino acids at positions 355 and 377 were important for dictating 16:0-CoA versus 18:0-CoA chain length specificity. Simultaneously converting alanine 355 and valine 377 of FAR5 to the corresponding FAR8 residues, leucine and methionine, respectively, almost fully converted FAR5 specificity from 18:0-CoA to 16:0-CoA. The reciprocal amino acid conversions, L355A and M377V, made in the active FAR8-S363P mutant background converted its specificity from 16:0-CoA to 18:0-CoA. This study is an important advancement in the engineering of highly active FAR proteins with desired specificities for the production of fatty alcohols with industrial value.

Turning Saccharomyces cerevisiae into a Frataxin-Independent Organism

PubMed Central

Yoon, Heeyong; Knight, Simon A. B.; Pandey, Alok; Pain, Jayashree; Turkarslan, Serdar; Pain, Debkumar; Dancis, Andrew

2015-01-01

Frataxin (Yfh1 in yeast) is a conserved protein and deficiency leads to the neurodegenerative disease Friedreich’s ataxia. Frataxin is a critical protein for Fe-S cluster assembly in mitochondria, interacting with other components of the Fe-S cluster machinery, including cysteine desulfurase Nfs1, Isd11 and the Isu1 scaffold protein. Yeast Isu1 with the methionine to isoleucine substitution (M141I), in which the E. coli amino acid is inserted at this position, corrected most of the phenotypes that result from lack of Yfh1 in yeast. This suppressor Isu1 behaved as a genetic dominant. Furthermore frataxin-bypass activity required a completely functional Nfs1 and correlated with the presence of efficient scaffold function. A screen of random Isu1 mutations for frataxin-bypass activity identified only M141 substitutions, including Ile, Cys, Leu, or Val. In each case, mitochondrial Nfs1 persulfide formation was enhanced, and mitochondrial Fe-S cluster assembly was improved in the absence of frataxin. Direct targeting of the entire E. coli IscU to ∆yfh1 mitochondria also ameliorated the mutant phenotypes. In contrast, expression of IscU with the reverse substitution i.e. IscU with Ile to Met change led to worsening of the ∆yfh1 phenotypes, including severely compromised growth, increased sensitivity to oxygen, deficiency in Fe-S clusters and heme, and impaired iron homeostasis. A bioinformatic survey of eukaryotic Isu1/prokaryotic IscU database entries sorted on the amino acid utilized at the M141 position identified unique groupings, with virtually all of the eukaryotic scaffolds using Met, and the preponderance of prokaryotic scaffolds using other amino acids. The frataxin-bypassing amino acids Cys, Ile, Leu, or Val, were found predominantly in prokaryotes. This amino acid position 141 is unique in Isu1, and the frataxin-bypass effect likely mimics a conserved and ancient feature of the prokaryotic Fe-S cluster assembly machinery. PMID:25996596

Repairing oxidized proteins in the bacterial envelope using respiratory chain electrons

PubMed Central

Henry, Camille; Agrebi, Rym; Vergnes, Alexandra; Oheix, Emmanuel; Bos, Julia; Leverrier, Pauline; Espinosa, Leon; Szewczyk, Joanna; Vertommen, Didier; Iranzo, Olga; Collet, Jean-François; Barras, Frédéric

2015-01-01

The reactive species of oxygen (ROS) and chlorine (RCS) damage cellular components, potentially leading to cell death. In proteins, the sulfur-containing amino acid methionine (Met) is converted to methionine sulfoxide (Met-O), which can cause a loss of biological activity. To rescue proteins with Met-O residues, living cells express methionine sulfoxide reductases (Msrs) in most subcellular compartments, including the cytosol, mitochondria and chloroplasts 1-3. Here, we report the identification of an enzymatic system, MsrPQ, repairing Met-O containing proteins in the bacterial cell envelope, a compartment particularly exposed to the ROS and RCS generated by the host defense mechanisms. MsrP, a molybdo-enzyme, and MsrQ, a heme-binding membrane protein, are widely conserved throughout Gram-negative bacteria, including major human pathogens. MsrPQ synthesis is induced by hypochlorous acid (HOCl), a powerful antimicrobial released by neutrophils. Consistently, MsrPQ is essential for the maintenance of envelope integrity under bleach stress, rescuing a wide series of structurally unrelated periplasmic proteins from Met oxidation, including the primary periplasmic chaperone SurA. For this activity, MsrPQ uses electrons from the respiratory chain, which represents a novel mechanism to import reducing equivalents into the bacterial cell envelope. A remarkable feature of MsrPQ is its capacity to reduce both R- and S- diastereoisomers of Met-O, making this oxidoreductase complex functionally different from previously identified Msrs. The discovery that a large class of bacteria contain a single, non-stereospecific enzymatic complex fully protecting Met residues from oxidation should prompt search for similar systems in eukaryotic subcellular oxidizing compartments, including the endoplasmic reticulum (ER). PMID:26641313

Influenza virus site recognized by a murine helper T cell specific for H1 strains. Localization to a nine amino acid sequence in the hemagglutinin molecule.

PubMed

Hackett, C J; Dietzschold, B; Gerhard, W; Ghrist, B; Knorr, R; Gillessen, D; Melchers, F

1983-08-01

The functional helper T cell line Vir-2, derived from a PR8 (H1N1) influenza virus-immunized BALB/c mouse, proliferates in response to syngeneic antigen-presenting cells and naturally occurring strains of subtype H1 human influenza virus from 1934-1957 and 1977-1980 isolates. A conserved region of the hemagglutinin molecule around amino acid position 115 in the heavy chain (HA1) was implicated as being important in this recognition by the lack of stimulatory activity associated with a glutamic acid to lysine substitution at position 115 in the laboratory mutant RV6, derived from wild-type PR8. Characterization of the stimulatory determinant on the wild-type hemagglutinin molecule was then undertaken using cleavage products and synthetic peptides. Vir-2 cells recognized the reduced and alkylated purified HA1 of PR8 virus, and this reactivity was retained after cleavage at methionine and tryptophan residues. High-pressure liquid chromatography separation of cleavage fragments indicated that a short sequence of the HA1 containing residue 115 was being recognized. This recognition was localized to a nine amino acid segment (positions 111-119) by assaying stimulation with synthetic peptide homologues of different lengths from that region. As with native hemagglutinin, Vir-2 cells responded to active peptides when presented by H-2d but not H-2k antigen-presenting cells.

Folic acid mitigated cardiac dysfunction by normalizing the levels of tissue inhibitor of metalloproteinase and homocysteine-metabolizing enzymes postmyocardial infarction in mice

PubMed Central

Qipshidze, Natia; Tyagi, Neetu; Sen, Utpal; Givvimani, Srikanth; Metreveli, Naira; Lominadze, David

2010-01-01

Myocardial infarction (MI) results in significant metabolic derangement, causing accumulation of metabolic by product, such as homocysteine (Hcy). Hcy is a nonprotein amino acid generated during nucleic acid methylation and demethylation of methionine. Folic acid (FA) decreases Hcy levels by remethylating the Hcy to methionine, by 5-methylene tetrahydrofolate reductase (5-MTHFR). Although clinical trials were inconclusive regarding the role of Hcy in MI, in animal models, the levels of 5-MTHFR were decreased, and FA mitigated the MI injury. We hypothesized that FA mitigated MI-induced injury, in part, by mitigating cardiac remodeling during chronic heart failure. Thus, MI was induced in 12-wk-old male C57BL/J mice by ligating the left anterior descending artery, and FA (0.03 g/l in drinking water) was administered for 4 wk after the surgery. Cardiac function was assessed by echocardiography and by a Millar pressure-volume catheter. The levels of Hcy-metabolizing enzymes, cystathionine β-synthase (CBS), cystathionine γ-lyase (CSE), and 5-MTHFR, were estimated by Western blot analyses. The results suggest that FA administered post-MI significantly improved cardiac ejection fraction and induced tissue inhibitor of metalloproteinase, CBS, CSE, and 5-MTHFR. We showed that FA supplementation resulted in significant improvement of myocardial function after MI. The study eluted the importance of homocysteine (Hcy) metabolism and FA supplementation in cardiovascular disease. PMID:20802128

Bio-inspired nitrile hydration by peptidic ligands based on L-cysteine, L-methionine or L-penicillamine and pyridine-2,6-dicarboxylic acid.

PubMed

Byrne, Cillian; Houlihan, Kate M; Devi, Prarthana; Jensen, Paul; Rutledge, Peter J

2014-12-12

Nitrile hydratase (NHase, EC 4.2.1.84) is a metalloenzyme which catalyses the conversion of nitriles to amides. The high efficiency and broad substrate range of NHase have led to the successful application of this enzyme as a biocatalyst in the industrial syntheses of acrylamide and nicotinamide and in the bioremediation of nitrile waste. Crystal structures of both cobalt(III)- and iron(III)-dependent NHases reveal an unusual metal binding motif made up from six sequential amino acids and comprising two amide nitrogens from the peptide backbone and three cysteine-derived sulfur ligands, each at a different oxidation state (thiolate, sulfenate and sulfinate). Based on the active site geometry revealed by these crystal structures, we have designed a series of small-molecule ligands which integrate essential features of the NHase metal binding motif into a readily accessible peptide environment. We report the synthesis of ligands based on a pyridine-2,6-dicarboxylic acid scaffold and L-cysteine, L-S-methylcysteine, L-methionine or L-penicillamine. These ligands have been combined with cobalt(III) and iron(III) and tested as catalysts for biomimetic nitrile hydration. The highest levels of activity are observed with the L-penicillamine ligand which, in combination with cobalt(III), converts acetonitrile to acetamide at 1.25 turnovers and benzonitrile to benzamide at 1.20 turnovers.

Short-term consumption of a plant protein diet does not improve glucose homeostasis of young C57BL/6J mice.

PubMed

Lamming, Dudley W; Baar, Emma L; Arriola Apelo, Sebastian I; Tosti, Valeria; Fontana, Luigi

2017-12-07

Recently, it has become apparent that dietary macronutrient composition has a profound impact on metabolism, health and even lifespan. Work from many laboratories now suggest that dietary protein quality - the precise amino acid composition of the diet, as well as possibly the source of dietary protein - may also be critical in regulating the impact of diet on health. Perhaps in part due to the naturally low methionine content of plants, vegan diets are associated with a decreased risk of diabetes and improved insulin sensitivity, but this association is confounded by the lower overall protein intake of vegans. Here, we test the effect of consuming isocaloric rodent diets with similar amino acid profiles derived from either plant protein or dairy protein. We find that male C57BL/6J mice consuming either diet have similar glycemic control, as assessed by glucose, insulin, and pyruvate tolerance tests, and have similar overall body composition. We conclude that short-term feeding of plant protein has no positive or negative effect on the metabolic health of young male C57BL/6J mice, and suggest that dietary interventions that alter either dietary protein levels or the levels of specific essential amino acids are more likely to improve metabolic health than alterations in dietary protein source.

A Better Understanding of Protein Structure and Function by the Synthesis and Incorporation of Selenium- and Tellurium Containing Tryptophan Analogs

DOE Office of Scientific and Technical Information (OSTI.GOV)

Helmey, Sherif Samir; Rice, Ambrose Eugene; Hatch, Duane Michael

Unnatural heavy metal-containing amino acid analogs have shown to be very important in the analysis of protein structure, using methods such as X-ray crystallography, mass spectroscopy, and NMR spectroscopy. Synthesis and incorporation of selenium-containing methionine analogs has already been shown in the literature however with some drawbacks due to toxicity to host organisms. Thus synthesis of heavy metal tryptophan analogs should prove to be more effective since the amino acid tryptophan is naturally less abundant in many proteins. For example, bioincorporation of β-seleno[3,2-b]pyrrolyl-L-alanine ([4,5]SeTrp) and β-selenolo[2,3-b]pyrrolyl-L-alanine ([6,7]SeTrp) has been shown in the following proteins without structural or catalytic perturbations: humanmore » annexin V, barstar, and dihydrofolate reductase. The reported synthesis of these Se-containing analogs is currently not efficient for commercial purposes. Thus a more efficient, concise, high-yield synthesis of selenotryptophan, as well as the corresponding, tellurotryptophan, will be necessary for wide spread use of these unnatural amino acid analogs. This research will highlight our progress towards a synthetic route of both [6,7]SeTrp and [6,7]TeTrp, which ultimately will be used to study the effect on the catalytic activity of Lignin Peroxidase (LiP).« less

Novel L-amino acid oxidase with algicidal activity against toxic cyanobacterium Microcystis aeruginosa synthesized by a bacterium Aquimarina sp.

PubMed

Chen, Wen Ming; Sheu, Fu Sian; Sheu, Shih Yi

2011-09-10

A brownish yellow pigmented bacterial strain, designated antisso-27, was recently isolated from a water area of saltpan in Southern Taiwan. Phylogenetic analyses based on 16S rRNA gene sequences indicate that strain antisso-27 belongs the genus Aquimarina in the family Flavobacteriacea and its only closest neighbor is Aquimarina spongiae (96.6%). Based on screening for algicidal activity, strain antisso-27 exhibits potent activity against the toxic cyanobacterium Microcystis aeruginosa. Both the strain antisso-27 bacterial culture and its culture filtrate show algicidal activity against the toxic cyanobacterium, indicating that an algicidal substance is released from strain antisso-27. The algicidal activity of strain antisso-27 occurs during the late stationary phase of bacterial growth. Strain antisso-27 can synthesize an algicidal protein with a molecular mass of 190 kDa, and its isoelectric point is approximately 9.4. This study explores the nature of this algicidal protein such as L-amino acid oxidase with broad substrate specificity. The enzyme is most active with L-leucine, L-isoleucine, L-methionine and L-valine and the hydrogen peroxide generated by its catalysis mediates algicidal activity. This is the first report on an Aquimarina strain algicidal to the toxic M. aeruginosa and the algicidal activity is generated through its enzymatic activity of L-amino acid oxidase. Copyright © 2011 Elsevier Inc. All rights reserved.

In situ visualization of newly synthesized proteins in environmental microbes using amino acid tagging and click chemistry

PubMed Central

Hatzenpichler, Roland; Scheller, Silvan; Tavormina, Patricia L; Babin, Brett M; Tirrell, David A; Orphan, Victoria J

2014-01-01

Here we describe the application of a new click chemistry method for fluorescent tracking of protein synthesis in individual microorganisms within environmental samples. This technique, termed bioorthogonal non-canonical amino acid tagging (BONCAT), is based on the in vivo incorporation of the non-canonical amino acid L-azidohomoalanine (AHA), a surrogate for l-methionine, followed by fluorescent labelling of AHA-containing cellular proteins by azide-alkyne click chemistry. BONCAT was evaluated with a range of phylogenetically and physiologically diverse archaeal and bacterial pure cultures and enrichments, and used to visualize translationally active cells within complex environmental samples including an oral biofilm, freshwater and anoxic sediment. We also developed combined assays that couple BONCAT with ribosomal RNA (rRNA)-targeted fluorescence in situ hybridization (FISH), enabling a direct link between taxonomic identity and translational activity. Using a methanotrophic enrichment culture incubated under different conditions, we demonstrate the potential of BONCAT-FISH to study microbial physiology in situ. A direct comparison of anabolic activity using BONCAT and stable isotope labelling by nano-scale secondary ion mass spectrometry (15NH3 assimilation) for individual cells within a sediment-sourced enrichment culture showed concordance between AHA-positive cells and 15N enrichment. BONCAT-FISH offers a fast, inexpensive and straightforward fluorescence microscopy method for studying the in situ activity of environmental microbes on a single-cell level. PMID:24571640