Preparation of 4-amino-2,4-dioxobutanoic acid

DOEpatents

Unkefer, Pat J.; Martinez, Rodolfo A.; Glass, David R.

2016-03-22

A process for synthesizing 4-amino-2,4-dioxobutanoate involves reacting a dialkyl oxalate with an alkoxide in ethanol to form a reaction mixture, and afterward adding an alkyl cyano acetate to the reaction mixture and allowing a reaction to proceed under conditions suitable to form a first reaction product of the formula diethyl 2-cyano-3-hydroxy-butenedioate, and then isolating the diethyl 2-cyano-3-hydroxy-butenedioate, and afterward reacting the diethyl-2-cyano-3-hydroxy-butenedioate with an aqueous hydroxide under conditions suitable to form 4-amino-2,4-dioxobutanoate. The 4-amino-2,4-dioxobutanoate may be acidified into 4-amino-2,4-dioxobutanoic acid.

Weight-loss diets and 2-y changes in circulating amino acids in 2 randomized intervention trials.

PubMed

Zheng, Yan; Ceglarek, Uta; Huang, Tao; Li, Lerong; Rood, Jennifer; Ryan, Donna H; Bray, George A; Sacks, Frank M; Schwarzfuchs, Dan; Thiery, Joachim; Shai, Iris; Qi, Lu

2016-02-01

Circulating amino acids, such as branched-chain amino acids (BCAAs) and aromatic amino acids (AAAs), have been associated with diabetes risk; however, little is known about how a long-term dietary intervention for weight loss affects circulating amino acids. We examined the effects of weight-loss diets on long-term changes in plasma amino acids and the associations of these changes with weight loss and the improvement of insulin resistance. We repeatedly measured plasma amino acid profiles over 2 y in overweight or obese participants from 2 randomized, dietary intervention, weight-loss trials [774 subjects from the POUNDS LOST (Preventing Overweight Using Novel Dietary Strategies Trial) and 318 subjects from the DIRECT (Dietary Intervention Randomized Controlled Trial)]. Intervention diets consistently lowered most of the amino acid concentrations, including BCAAs and AAAs, in both trials. In the POUNDS LOST, average-protein diets (15% of daily energy) showed stronger effects than did high-protein diets (25% of daily energy) on reducing concentrations of the diabetes-associated BCAA valine at 6 mo independent of the weight change. In both trials, weight loss was directly related to the concurrent reduction of the BCAAs leucine and isoleucine, the AAAs tyrosine and phenylalanine, and 4 other amino acids. For example, per kilogram of weight loss, there was a 0.04-SD decrease in log tyrosine (∼0.6 μmol/L) in both trials. In addition, we showed that reductions in alanine and the AAA tyrosine were significantly related to improved insulin resistance (measured with the use of the homeostasis model assessment of insulin resistance), independent of weight loss, in both trials (both P < 0.05). For example, per 1-SD decrease in log tyrosine (∼17 μmol/L), there was a 0.04-SD (∼3%) improvement in insulin resistance in the POUNDS LOST and a 0.13-SD (∼8%) improvement in insulin resistance in the DIRECT. Our findings underscore the potential importance of dietary

Racemic resolution of some DL-amino acids using Aspergillus fumigatus L-amino acid oxidase.

PubMed

Singh, Susmita; Gogoi, Binod K; Bezbaruah, Rajib L

2011-07-01

The ability of Aspergillus fumigatus L-amino acid oxidase (L-aao) to cause the resolution of racemic mixtures of DL-amino acids was investigated with DL-alanine, DL-phenylalanine, DL-tyrosine, and DL-aspartic acid. A chiral column, Crownpak CR+ was used for the analysis of the amino acids. The enzyme was able to cause the resolution of the three DL-amino acids resulting in the production of optically pure D-alanine (100% resolution), D-phenylalanine (80.2%), and D-tyrosine (84.1%), respectively. The optically pure D-amino acids have many uses and thus can be exploited industrially. This is the first report of the use of A. fumigatus L: -amino acid oxidase for racemic resolution of DL-amino acids.

Characterization of CeO{sub 2} crystals synthesized with different amino acids

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

Atla, Shashi B.; Wu, Min-Nan; Pan, Wei

We investigated the relationship between the structures of the CeO{sub 2} products (particle size, morphology and their characteristics) prepared using different amino acids. Cerium hydroxide carbonate precursors were initially prepared by a hydrothermal method and were subsequently converted to CeO{sub 2} by its thermal decomposition. Various amino acids were used as structure-directing agents in the presence of cerium nitrate and urea as precursors. The results indicate morphology selectivity using different amino acids; CeO{sub 2} structures, such as quasi-prism-sphere, straw-bundle, urchin-flower like and polyhedron prisms, indeed could be produced. Raman and photoluminescence studies indicate the presence of oxygen vacancies in themore » CeO{sub 2} samples. Photoluminescence spectra of CeO{sub 2} with L-Valine exhibit stronger emission compared with other amino acids utilized under this study, indicating the higher degree of defects in these particles. This study clearly indicates that the degree of defects varied in the presence of different amino acids. Improved precision to control the crystal morphology is important in various material applications and our study provides a novel method to achieve this specificity. - Highlights: • We used urea hydrolysis of process for synthesis of CeO{sub 2}. • Structures have been directed using various amino acids. • We obtained straw bundle-like, quasi prism-sphere, polyhedron prisms and urchin flower-like based on amino acids. • We have found that amino acids could achieve the specificity of different degrees of defects. • This could provide the “tailor-make” of cerium crystals.« less

40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

Code of Federal Regulations, 2011 CFR

2011-07-01

... identified generically as 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[(1-sulfo-2-naphthalenyl)azo...

40 CFR 721.5262 - 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4...

Code of Federal Regulations, 2010 CFR

2010-07-01

... identified generically as 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2,7-Naphthalenedisulfonic acid, 5-[[4-chloro-6-[substituted] amino]-1,3,5-triazin-2-yl]amino]-4-hydroxy-3-[(1-sulfo-2-naphthalenyl)azo...

Extraterrestrial material analysis: loss of amino acids during liquid-phase acid hydrolysis

NASA Astrophysics Data System (ADS)

Buch, Arnaud; Brault, Amaury; Szopa, Cyril; Freissinet, Caroline

2015-04-01

Searching for building blocks of life in extraterrestrial material is a way to learn more about how life could have appeared on Earth. With this aim, liquid-phase acid hydrolysis has been used, since at least 1970 , in order to extract amino acids and other organic molecules from extraterrestrial materials (e.g. meteorites, lunar fines) or Earth analogues (e.g. Atacama desert soil). This procedure involves drastic conditions such as heating samples in 6N HCl for 24 h, either under inert atmosphere/vacuum, or air. Analysis of the hydrolyzed part of the sample should give its total (free plus bound) amino acid content. The present work deals with the influence of the 6N HCl hydrolysis on amino acid degradation. Our experiments have been performed on a standard solution of 17 amino acids. After liquid-phase acid hydrolysis (6N HCl) under argon atmosphere (24 h at 100°C), the liquid phase was evaporated and the dry residue was derivatized with N-Methyl-N-(t-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) and dimethylformamide (DMF), followed by gas chromatography-mass spectrometry analysis. After comparison with derivatized amino acids from the standard solution, a significant reduction of the chromatographic peak areas was observed for most of the amino acids after liquid-phase acid hydrolysis. Furthermore, the same loss pattern was observed when the amino acids were exposed to cold 6N HCl for a short amount of time. The least affected amino acid, i.e. glycine, was found to be 73,93% percent less abundant compared to the non-hydrolyzed standard, while the most affected, i.e. histidine, was not found in the chromatograms after hydrolysis. Our experiments thereby indicate that liquid-phase acid hydrolysis, even under inert atmosphere, leads to a partial or total loss of all of the 17 amino acids present in the standard solution, and that a quick cold contact with 6N HCl is sufficient to lead to a loss of amino acids. Therefore, in the literature, the reported increase

Importance of individual amino acids in the Switch I region in eEF2 studied by functional complementation in S. cerevisiae.

PubMed

Bartish, Galyna; Nygård, Odd

2008-05-01

Elongation factor 2 (eEF2) is a member of the G-protein super family. G-proteins undergo conformational changes associated with binding of the guanosine nucleotide and hydrolysis of the bound GTP. These structural rearrangements affects the Switch I region (also known as the Effector loop). We have studied the role of individual amino acids in the Switch I region (amino acids 25-73) of S. cerevisiae eEF2 using functional complementation in yeast. 21 point mutations in the Switch I region were created by site-directed mutagenesis. Mutants K49R, E52Q, A53G, F55Y, K60R, Q63A, T68S, I69M and A73G were functional while mutants R54H, F55N, D57A, D57E, D57S, R59K, R59M, Q63E, R65A, R65N, T68A and T68M were inactive. Expression of mutants K49R, A53G, Q63A, I69M and A73G was associated with markedly decreased growth rates and yeast cells expressing mutants A53G and I69M became temperature sensitive. The functional capacity of eEF2 in which the major part Switch I (amino acids T56 to I69) was converted into the homologous sequence found in EF-G from E. coli was also studied. This protein chimera could functionally replace yeast eEF2 in vivo. Yeast cells expressing this mutant grew extremely slowly, showed increased cell death and became temperature sensitive. The ability of the mutant to replace authentic eEF2 in vivo indicates that the structural rearrangement of Switch I necessary for eEF2 function is similar in eukaryotes and bacteria. The effect of two point mutations in the P-loop was also studied. Mutant A25G but not A25V could functionally replace yeast eEF2 even if cells expressing the mutant grew slowly. The A25G mutation converted the consensus sequences AXXXXGK[T/S] in eEF2 to the corresponding motif GXXXXGK[T/S] found in all other G-proteins, suggesting that the alanine found in the P-loop of peptidyltranslocases are not essential for function.

Enhanced Synthesis of Alkyl Amino Acids in Miller's 1958 H2S Experiment

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, H. James; Callahan, Michael P.; Dworkin, James P.; Glavin, Daniel P.; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Stanley Miller's 1958 H2S-containing experiment, which included a simulated prebiotic atmosphere of methane (CH4), ammonia (NH3), carbon dioxide (CO2), and hydrogen sulfide (H2S) produced several alkyl amino acids, including the alpha-, beta-, and gamma-isomers of aminobutyric acid (ABA) in greater relative yields than had previously been reported from his spark discharge experiments. In the presence of H2S, aspariic and glutamic acids could yield alkyl amino acids via the formation of thioimide intermediates. Radical chemistry initiated by passing H2S through a spark discharge could have also enhanced alkyl amino acid synthesis by generating alkyl radicals that can help form the aldehyde and ketone precursors to these amino acids. We propose mechanisms that may have influenced the synthesis of certain amino acids in localized environments rich in H2S and lightning discharges, similar to conditions near volcanic systems on the early Earth, thus contributing to the prebiotic chemical inventory of the primordial Earth.

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.

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 2-(3-phenylbutylidene...

40 CFR 721.1728 - Benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... New Uses for Specific Chemical Substances § 721.1728 Benzoic acid, 2-(3-phenylbutylidene)amino... substance identified as benzoic acid, 2-(3-phenylbutylidene)amino-, methyl ester (PMN P-85-1211) is subject... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 2-(3-phenylbutylidene...

Physiological role of D-amino acid-N-acetyltransferase of Saccharomyces cerevisiae: detoxification of D-amino acids.

PubMed

Yow, Geok-Yong; Uo, Takuma; Yoshimura, Tohru; Esaki, Nobuyoshi

2006-03-01

Saccharomyces cerevisiae is sensitive to D-amino acids: those corresponding to almost all proteinous L-amino acids inhibit the growth of yeast even at low concentrations (e.g. 0.1 mM). We have determined that D-amino acid-N-acetyltransferase (DNT) of the yeast is involved in the detoxification of D-amino acids on the basis of the following findings. When the DNT gene was disrupted, the resulting mutant was far less tolerant to D-amino acids than the wild type. However, when the gene was overexpressed with a vector plasmid p426Gal1 in the wild type or the mutant S. cerevisiae as a host, the recombinant yeast, which was found to show more than 100 times higher DNT activity than the wild type, was much more tolerant to D-amino acids than the wild type. We further confirmed that, upon cultivation with D-phenylalanine, N-acetyl-D-phenylalanine was accumulated in the culture but not in the wild type and hpa3Delta cells overproducing DNT cells. Thus, D-amino acids are toxic to S. cerevisiae but are detoxified with DNT by N-acetylation preceding removal from yeast cells.

An Assay of Selected Serum Amino Acids in Patients with Type 2 Diabetes Mellitus.

PubMed

Drábková, Petra; Šanderová, Jana; Kovařík, Jakub; kanďár, Roman

2015-01-01

Amino acids are the building blocks of proteins. In case of insulin resistance, which is typical for type 2 diabetes mellitus (T2DM), proteolysis is increased and protein synthesis is decreased; therefore, we can observe changes in the levels of amino acids in diabetics vs. non-diabetics. The aim of this study was to find differences in the levels of selected amino acids between patients with diabetes (type 2) and a control group. Amino acids were derivatized with naphthalene-2,3-dicarboxaldehyde in the presence of potassium cyanide to form fluorescent 1-cyanobenz(f)isoindole product. Amino acids derivatives were measured using a high-performance liquid chromatography with fluorescence detection. The serum levels of glucose were determined using an automatic biochemistry analyzer, glycated hemoglobin HbA1c was measured by cation exchange chromatography. A total of 19 serum amino acids in T2DM patients and non-diabetics were measured. There were 9 amino acids, which were significantly different in these groups (p<0.05). Significantly decreased levels of arginine, asparagine, glycine, serine, threonine and significantly increased levels of alanine, isoleucine, leucine, valine in diabetics were found. Significant difference in metabolism of amino acids between diabetics and non-diabetics were observed. The altered levels of amino acids in diabetic patients could be a suitable predictor of diabetes.

Engineering an ATP-dependent D-Ala:D-Ala ligase for synthesizing amino acid amides from amino acids.

PubMed

Miki, Yuta; Okazaki, Seiji; Asano, Yasuhisa

2017-05-01

We successfully engineered a new enzyme that catalyzes the formation of D-Ala amide (D-AlaNH 2 ) from D-Ala by modifying ATP-dependent D-Ala:D-Ala ligase (EC 6.3.2.4) from Thermus thermophilus, which catalyzes the formation of D-Ala-D-Ala from two molecules of D-Ala. The new enzyme was created by the replacement of the Ser293 residue with acidic amino acids, as it was speculated to bind to the second D-Ala of D-Ala-D-Ala. In addition, a replacement of the position with Glu performed better than that with Asp with regards to specificity for D-AlaNH 2 production. The S293E variant, which was selected as the best enzyme for D-AlaNH 2 production, exhibited an optimal activity at pH 9.0 and 40 °C for D-AlaNH 2 production. The apparent K m values of this variant for D-Ala and NH 3 were 7.35 mM and 1.58 M, respectively. The S293E variant could catalyze the synthesis of 9.3 and 35.7 mM of D-AlaNH 2 from 10 and 50 mM D-Ala and 3 M NH 4 Cl with conversion yields of 93 and 71.4 %, respectively. This is the first report showing the enzymatic formation of amino acid amides from amino acids.

Regeneration of the intestinal mucosa in Eimeria and E. Coli challenged broilers supplemented with amino acids.

PubMed

Gottardo, E T; Prokoski, K; Horn, D; Viott, A D; Santos, T C; Fernandes, J I M

2016-05-01

The aim of this study was to evaluate the regeneration of the intestinal mucosa in Eimeria and E. coli challenged broilers supplemented with glutamine, arginine, and threonine. Six hundred male broilers at one d of age from the Cobb strain were utilized. The design was completely randomized using a 2×3 factorial design (unchallenged and challenged and 3 diets). A commercial diet was used as a control and 2 other diets were formulated with glutamine (1.5 and 3% Aminogut®), arginine (1 and 2% L-Arginine), and threonine (1 and 2% L-threonine). The animals that consumed diets supplemented with amino acids presented better (P<0.05) feed conversion in the period from one to 42 d of age. The ability of cell proliferation and the villus:crypt ratio in response to enteric challenge were greater (P<0.05) for broilers that received diets supplemented with amino acids. High levels of amino acids in the experimental feeds reflected in greater protein levels in poultry house litter, and they did not interfere with ammonia production. The supplementation of diets with trophic amino acids can positively contribute to the regeneration and proliferation of the intestinal mucosa in broilers and to the maintenance of zootechnical performance when submitted to enteric challenges. © 2016 Poultry Science Association Inc.

Anharmonicity in Amino Acids

NASA Astrophysics Data System (ADS)

Martinho, Herculano; Lima, Thamires; Ishikawa, Mariana

2012-02-01

Two special dynamical transitions of universal character have been recently observed in macromolecules (lysozyme, myoglobin, bacteriorhodopsin, DNA, and RNA) at T^*˜100 - 150 K and TD˜180 - 220 K. The underlying mechanisms governing these transitions have been subject of debate. In the present work it is reported a survey on the temperature dependence of structural, vibrational and thermodynamical properties of a nearly anhydrous amino acid (orthorhombic polymorph of the amino acids L-cysteine and L-proline at a hydration level of 3.5%). The temperature dependence of X-Ray diffraction, Raman spectroscopy, and specific heat were considered. The data were analyzed considering amino acid-amino acid, amino acid-water, and water-water phonon-phonon interactions, and molecular rotors activation. Our results indicated that the two referred temperatures define the triggering of very simple and specific events that govern all the interactions of the biomolecule: activation of CH2 rigid rotors (Tamino acid and water dimer vibrational modes (T^*TD).

The spark discharge synthesis of amino acids from various hydrocarbons

NASA Technical Reports Server (NTRS)

Ring, D.; Miller, S. L.

1984-01-01

The spark discharge synthesis of amino acids using an atmosphere of CH4+N2+H2O+NH3 has been investigated with variable pNH3. The amino acids produced using higher hydrocarbons (ethane, ethylene, acetylene, propane, butane, and isobutane) instead of CH4 were also investigated. There was considerable range in the absolute yields of amino acids, but the yields relative to glycine (or alpha-amino-n-butyric acid) were more uniform. The relative yields of the C3 to C6 aliphatic alpha-amino acids are nearly the same (with a few exceptions) with all the hydrocarbons. The glycine yields are more variable. The precursors to the C3-C6 aliphatic amino acids seem to be produced in the same process, which is separate from the synthesis of glycine precursors. It may be possible to use these relative yields as a signature for a spark discharge synthesis provided corrections can be made for subsequent decomposition events (e.g. in the Murchison meteorite).

Biochemical Characterization of β-Amino Acid Incorporation in Fluvirucin B 2 Biosynthesis

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

Barajas, Jesus F.; Zargar, Amin; Pang, Bo

Naturally occurring lactams, such as the polyketide-derived macrolactams, provide a diverse class of natural products that could enhance existing chemically produced lactams. While β-amino acid loading in the fluvirucin B 2 polyketide pathway has been proposed by a previously identified putative biosynthetic gene cluster, biochemical characterization of the complete loading enzymes has not been described. In this paper, we elucidate the complete biosynthetic pathway of the β-amino acid loading pathway in fluvirucin B 2 biosynthesis. We demonstrate the promiscuity of the loading pathway to utilize a range of amino acids and further illustrate the ability to introduce non-native acyl transferasesmore » to selectively transfer β-amino acids onto a PKS loading platform. The results presented here provide a detailed biochemical description of β-amino acid selection and will further aid in future efforts to develop engineered lactam-producing PKS platforms.« less

Biochemical Characterization of β-Amino Acid Incorporation in Fluvirucin B 2 Biosynthesis

DOE PAGES

Barajas, Jesus F.; Zargar, Amin; Pang, Bo; ...

2018-03-30

Naturally occurring lactams, such as the polyketide-derived macrolactams, provide a diverse class of natural products that could enhance existing chemically produced lactams. While β-amino acid loading in the fluvirucin B 2 polyketide pathway has been proposed by a previously identified putative biosynthetic gene cluster, biochemical characterization of the complete loading enzymes has not been described. In this paper, we elucidate the complete biosynthetic pathway of the β-amino acid loading pathway in fluvirucin B 2 biosynthesis. We demonstrate the promiscuity of the loading pathway to utilize a range of amino acids and further illustrate the ability to introduce non-native acyl transferasesmore » to selectively transfer β-amino acids onto a PKS loading platform. The results presented here provide a detailed biochemical description of β-amino acid selection and will further aid in future efforts to develop engineered lactam-producing PKS platforms.« less

40 CFR 721.10020 - Benzoic acid, 5-amino-2-chloro-, 1,1-dimethyl-2-oxo-2-(2-propenyloxy) ethyl ester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 5-amino-2-chloro-, 1,1... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10020 Benzoic acid, 5-amino-2-chloro... subject to reporting. (1) The chemical substance identified as benzoic acid, 5-amino-2-chloro-, 1,1...

40 CFR 721.10020 - Benzoic acid, 5-amino-2-chloro-, 1,1-dimethyl-2-oxo-2-(2-propenyloxy) ethyl ester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 5-amino-2-chloro-, 1,1... SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10020 Benzoic acid, 5-amino-2-chloro... subject to reporting. (1) The chemical substance identified as benzoic acid, 5-amino-2-chloro-, 1,1...

PCI-GC-MS-MS approach for identification of non-amino organic acid and amino acid profiles.

PubMed

Luan, Hemi; Yang, Lin; Ji, Fenfen; Cai, Zongwei

2017-03-15

Alkyl chloroformate have been wildly used for the fast derivatization of metabolites with amino and/or carboxyl groups, coupling of powerful separation and detection systems, such as GC-MS, which allows the comprehensive analysis of non-amino organic acids and amino acids. The reagents involving n-alkyl chloroformate and n-alcohol are generally employed for providing symmetric labeling terminal alkyl chain with the same length. Here, we developed an asymmetric labeling strategy and positive chemical ionization gas chromatography-tandem mass spectrometry (PCI-GC-MS-MS) approach for determination of non-amino organic acids and amino acids, as well as the short chain fatty acids. Carboxylic and amino groups could be selectively labelled by propyl and ethyl groups, respectively. The specific neutral loss of C 3 H 8 O (60Da), C 3 H 5 O 2 (74Da) and C 4 H 8 O 2 (88Da) were useful in the selective identification for qualitative analysis of organic acids and amino acid derivatives. PCI-GC-MS-MS using multiple reaction monitoring (MRM) was applied for semi-quantification of typical non-amino organic acids and amino acids. This method exhibited a wide range of linear range, good regression coefficient (R 2 ) and repeatability. The relative standard deviation (RSD) of targeted metabolites showed excellent intra- and inter-day precision (<5%). Our method provided a qualitative and semi-quantitative PCI-GC-MS-MS, coupled with alkyl chloroformate derivatization. Copyright © 2016 Elsevier B.V. All rights reserved.

40 CFR 721.9790 - Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[5-[[4-[bis(2-hydroxypropyl) amino]- 6-[(3...

Code of Federal Regulations, 2011 CFR

2011-07-01

.... with 2,2′,2″-nitrilotris[ethanol] (1:2); Benzenesulfonic acid, 5-[[4-[bis(2-hydroxyethyl)amino]-6-[(3... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenesulfonic acid, 2,2â²-(1,2-ethenediyl)bis[5-[[4-[bis(2-hydroxypropyl) amino]- 6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino...

40 CFR 721.9790 - Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[5-[[4-[bis(2-hydroxypropyl) amino]- 6-[(3...

Code of Federal Regulations, 2010 CFR

2010-07-01

.... with 2,2′,2″-nitrilotris[ethanol] (1:2); Benzenesulfonic acid, 5-[[4-[bis(2-hydroxyethyl)amino]-6-[(3... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenesulfonic acid, 2,2â²-(1,2-ethenediyl)bis[5-[[4-[bis(2-hydroxypropyl) amino]- 6-[(3-sulfophenyl)amino]-1,3,5-triazin-2-yl]amino...

Photochemical reaction of 2-(3-benzoylphenyl)propionic acid (ketoprofen) with basic amino acids and dipeptides.

PubMed

Suzuki, Tadashi; Shinoda, Mio; Osanai, Yohei; Isozaki, Tasuku

2013-08-22

Photoreaction of 2-(3-benzoylphenyl)propionic acid (ketoprofen, KP) with basic amino acids (histidine, lysine, and arginine) and dipeptides (carnosine and anserine) including a histidine moiety in phosphate buffer solution (pH 7.4) has been investigated with transient absorption spectroscopy. With UV irradiation KP(-) gave rise to a carbanion through a decarboxylation reaction, and the carbanion easily abstracted a proton from the surrounding molecule to yield a 3-ethylbenzophenone ketyl biradical (EBPH). The dipeptides as well as the basic amino acids were found to accelerate the proton transfer reaction whereas alanine and glycine had no effect on the reaction, revealing that these amino acids having a protonated side chain act as a proton donor. The formation quantum yield of EBPH was estimated to be fairly large by means of an actinometrical method with benzophenone, and the bimolecular reaction rate constant for the proton transfer between the carbanion and the protonated basic amino acids or the protonated dipeptides was successfully determined. It has become apparent that the bimolecular reaction rate constant for the proton transfer depended on the acid dissociation constant for the side chain of the amino acids for the first time. This reaction mechanism was interpreted by difference of the heat of reaction for each basic amino acid based on the thermodynamical consideration. These results strongly suggest that the side chain of the basic amino acid residue in protein should play an important role for photochemistry of KP in vivo.

Enantiomeric excesses in meteoritic amino acids

NASA Technical Reports Server (NTRS)

Cronin, J. R.; Pizzarello, S.

1997-01-01

Gas chromatographic-mass spectral analyses of the four stereoisomers of 2-amino-2,3-dimethylpentanoic acid (dl-alpha-methylisoleucine and dl-alpha-methylalloisoleucine) obtained from the Murchison meteorite show that the L enantiomer occurs in excess (7.0 and 9.1%, respectively) in both of the enantiomeric pairs. Similar results were obtained for two other alpha-methyl amino acids, isovaline and alpha-methylnorvaline, although the alpha hydrogen analogs of these amino acids, alpha-amino-n-butyric acid and norvaline, were found to be racemates. With the exception of alpha-amino-n-butyric acid, these amino acids are either unknown or of limited occurrence in the biosphere. Because carbonaceous chondrites formed 4.5 billion years ago, the results are indicative of an asymmetric influence on organic chemical evolution before the origin of life.

Membrane topology of rat sodium-coupled neutral amino acid transporter 2 (SNAT2).

PubMed

Ge, Yudan; Gu, Yanting; Wang, Jiahong; Zhang, Zhou

2018-07-01

Sodium-coupled neutral amino acid transporter 2 (SNAT2) is a subtype of the amino acid transport system A that is widely expressed in mammalian tissues. It plays critical roles in glutamic acid-glutamine circulation, liver gluconeogenesis and other biological pathway. However, the topology of the SNAT2 amino acid transporter is unknown. Here we identified the topological structure of SNAT2 using bioinformatics analysis, Methoxy-polyethylene glycol maleimide (mPEG-Mal) chemical modification, protease cleavage assays, immunofluorescence and examination of glycosylation. Our results show that SNAT2 contains 11 transmembrane domains (TMDs) with an intracellular N terminus and an extracellular C terminus. Three N-glycosylation sites were verified at the largest extracellular loop. This model is consistent with the previous model of SNAT2 with the exception of a difference in number of glycosylation sites. This is the first time to confirm the SNAT2 membrane topology using experimental methods. Our study on SNAT2 topology provides valuable structural information of one of the solute carrier family 38 (SLC38) members. Copyright © 2018 Elsevier B.V. All rights reserved.

Interaction of metal ions and amino acids - Possible mechanisms for the adsorption of amino acids on homoionic smectite clays

NASA Technical Reports Server (NTRS)

Gupta, A.; Loew, G. H.; Lawless, J.

1983-01-01

A semiempirical molecular orbital method is used to characterize the binding of amino acids to hexahydrated Cu(2+) and Ni(2+), a process presumed to occur when they are adsorbed in the interlamellar space of homoionic smectite clays. Five alpha-amino acids, beta-alanine, and gamma-aminobutyric acid were used to investigate the metal ion and amino acid specificity in binding. It was assumed that the alpha, beta, and gamma-amino acids would bind as bidentate anionic ligands, forming either 1:1 or 1:2 six-coordinated five, six, and seven-membered-ring chelate complexes, respectively. Energies of complex formation, optimized geometries, and electron and spin distribution were determined; and steric constraints of binding of the amino acids to the ion-exchanged cations in the interlamellar spacing of a clay were examined. Results indicate that hexahydrated Cu(2+) forms more stable complexes than hexahydrated Ni(2+) with all the amino acids studied. However, among these amino acids, complex formation does not favor the adsorption of the biological subset. Calculated energetics of complex formation and steric constraints are shown to predict that 1:1 rather than 1:2 metal-amino acid complexes are generally favored in the clay.

A reexamination of amino acids in lunar soil

NASA Technical Reports Server (NTRS)

Brinton, K. L. F.; Bada, J. L.; Arnold, J. R.

1993-01-01

Amino acids in lunar soils provide an important indicator of the level of prebiotic organic compounds on the moon. The results provide insight into the chemistry of amino acid precursors, and furthermore, given the flux of carbonaceous material to the moon, we can evaluate the survival of organics upon impact. The amino acid contents of both hydrolyzed and unhydrolyzed hot-water extracts of Apollo 17 lunar soil were determined using ophthaldialdehyde/N-acetyl cysteine (OPA/NAC) derivatization followed by HPLC analysis. Previous studies of lunar amino acids were inconclusive, as the technique used (derivatization with ninhydrin followed by HPLC analysis) was unable to discriminate between cosmogenic amino acids and terrestrial contaminants. Cosmogenic amino acids are racemic, and many of the amino acids found in carbonaceous meteorites such as Murchison, i.e., alpha-amino-i-butyric acid (aib), are extremely rare on Earth. The ninhydrin method does not distinguish amino acid enantiomers, nor does it detect alpha-alkyl amino acids such as aib, whereas the OPA/NAC technique does both.

Synthesis and Anti-microbial Activity of Novel Phosphatidylethanolamine-N-amino Acid Derivatives.

PubMed

Vijeetha, Tadla; Balakrishna, Marrapu; Karuna, Mallampalli Sri Lakshmi; Surya Koppeswara Rao, Bhamidipati Venkata; Prasad, Rachapudi Badari Narayana; Kumar, Koochana Pranay; Surya Narayana Murthy, Upadyaula

2015-01-01

The study involved synthesis of five novel amino acid derivatives of phosphatidylethanolamine isolated from egg yolk lecithin employing a three step procedure i) N-protection of L-amino acids with BOC anhydride in alkaline medium ii) condensation of - CO2H group of N-protected amino acid with free -NH2 of PE by a peptide linkage and iii) deprotection of N-protected group of amino acids to obtain phosphatidylethanolamine-N-amino acid derivatives in 60-75% yield. The five L-amino acids used were L glycine, L-valine, L-leucine, L-isoleucine and L-phenylalanine. The amino acid derivatives were screened for anti-baterial activity against B. subtilis, S. aureus, P. aeroginosa and E. coli taking Streptomycin as reference compound and anti-fungal activity against C. albicans, S. cervisiae, A. niger taking AmphotericinB as reference compound. All the amino acid derivatives exhibited extraordinary anti-bacterial activities about 3 folds or comparable to Streptomycin and moderate or no anti-fungal activity against Amphotericin-B.

Partial amino acid sequence of the branched chain amino acid aminotransferase (TmB) of E. coli JA199 pDU11

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

Feild, M.J.; Armstrong, F.B.

1987-05-01

E. coli JA199 pDU11 harbors a multicopy plasmid containing the ilv GEDAY gene cluster of S. typhimurium. TmB, gene product of ilv E, was purified, crystallized, and subjected to Edman degradation using a gas phase sequencer. The intact protein yielded an amino terminal 31 residue sequence. Both carboxymethylated apoenzyme and (/sup 3/H)-NaBH-reduced holoenzyme were then subjected to digestion by trypsin. The digests were fractionated using reversed phase HPLC, and the peptides isolated were sequenced. The borohydride-treated holoenzyme was used to isolate the cofactor-binding peptide. The peptide is 27 residues long and a comparison with known sequences of other aminotransferases revealedmore » limited homology. Peptides accounting for 211 of 288 predicted residues have been sequenced, including 9 residues of the carboxyl terminus. Comparison of peptides with the inferred amino acid sequence of the E. coli K-12 enzyme has helped determine the sequence of the amino terminal 59 residues; only two differences between the sequences are noted in this region.« less

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

Permeability of membranes to amino acids and modified amino acids: mechanisms involved in translocation

NASA Technical Reports Server (NTRS)

Chakrabarti, A. C.; Deamer, D. W. (Principal Investigator); Miller, S. L. (Principal Investigator)

1994-01-01

The amino acid permeability of membranes is of interest because they are one of the key solutes involved in cell function. Membrane permeability coefficients (P) for amino acid classes, including neutral, polar, hydrophobic, and charged species, have been measured and compared using a variety of techniques. Decreasing lipid chain length increased permeability slightly (5-fold), while variations in pH had only minor effects on the permeability coefficients of the amino acids tested in liposomes. Increasing the membrane surface charge increased the permeability of amino acids of the opposite charge, while increasing the cholesterol content decreased membrane permeability. The permeability coefficients for most amino acids tested were surprisingly similar to those previously measured for monovalent cations such as sodium and potassium (approximately 10(-12)-10(-13) cm s-1). This observation suggests that the permeation rates for the neutral, polar and charged amino acids are controlled by bilayer fluctuations and transient defects, rather than partition coefficients and Born energy barriers. Hydrophobic amino acids were 10(2) more permeable than the hydrophilic forms, reflecting their increased partition coefficient values. External pH had dramatic effects on the permeation rates for the modified amino acid lysine methyl ester in response to transmembrane pH gradients. It was established that lysine methyl ester and other modified short peptides permeate rapidly (P = 10(-2) cm s-1) as neutral (deprotonated) molecules. It was also shown that charge distributions dramatically alter permeation rates for modified di-peptides. These results may relate to the movement of peptides through membranes during protein translocation and to the origin of cellular membrane transport on the early Earth.

Thermal decomposition of the amino acids glycine, cysteine, aspartic acid, asparagine, glutamic acid, glutamine, arginine and histidine.

PubMed

Weiss, Ingrid M; Muth, Christina; Drumm, Robert; Kirchner, Helmut O K

2018-01-01

The pathways of thermal instability of amino acids have been unknown. New mass spectrometric data allow unequivocal quantitative identification of the decomposition products. Calorimetry, thermogravimetry and mass spectrometry were used to follow the thermal decomposition of the eight amino acids G, C, D, N, E, Q, R and H between 185 °C and 280 °C. Endothermic heats of decomposition between 72 and 151 kJ/mol are needed to form 12 to 70% volatile products. This process is neither melting nor sublimation. With exception of cysteine they emit mainly H 2 O, some NH 3 and no CO 2 . Cysteine produces CO 2 and little else. The reactions are described by polynomials, AA→ a NH 3 + b H 2 O+ c CO 2 + d H 2 S+ e residue, with integer or half integer coefficients. The solid monomolecular residues are rich in peptide bonds. Eight of the 20 standard amino acids decompose at well-defined, characteristic temperatures, in contrast to commonly accepted knowledge. Products of decomposition are simple. The novel quantitative results emphasize the impact of water and cyclic condensates with peptide bonds and put constraints on hypotheses of the origin, state and stability of amino acids in the range between 200 °C and 300 °C.

Identification of the fnx1+ and fnx2+ genes for vacuolar amino acid transporters in Schizosaccharomyces pombe.

PubMed

Chardwiriyapreecha, Soracom; Shimazu, Masamitsu; Morita, Tomotake; Sekito, Takayuki; Akiyama, Koichi; Takegawa, Kaoru; Kakinuma, Yoshimi

2008-06-25

We have identified the Schizosaccharomyces pombe SPBC3E7.06c gene (fnx2(+)) from a homology search with the fnx1(+) gene involving in G(0) arrest upon nitrogen starvation. Green fluorescent protein-fused Fnx1p and Fnx2p localized exclusively to the vacuolar membrane. Uptake of histidine or isoleucine by S. pombe cells was inhibited by concanamycin A, a specific inhibitor of the vacuolar H(+)-ATPase. Amino acid uptake was also defective in the vacuolar ATPase mutant, suggesting that vacuolar compartmentalization is critical for amino acid uptake by whole cells. In both Deltafnx1 and Deltafnx2 mutant cells, uptake of lysine, isoleucine or asparagine was impaired. These results suggest that fnx1(+) and fnx2(+) are involved in vacuolar amino acid uptake in S. pombe.

Amino acids

MedlinePlus

... this page: //medlineplus.gov/ency/article/002222.htm Amino acids To use the sharing features on this page, please enable JavaScript. Amino acids are organic compounds that combine to form proteins . ...

Amino acid analysis

NASA Technical Reports Server (NTRS)

Winitz, M.; Graff, J. (Inventor)

1974-01-01

The process and apparatus for qualitative and quantitative analysis of the amino acid content of a biological sample are presented. The sample is deposited on a cation exchange resin and then is washed with suitable solvents. The amino acids and various cations and organic material with a basic function remain on the resin. The resin is eluted with an acid eluant, and the eluate containing the amino acids is transferred to a reaction vessel where the eluant is removed. Final analysis of the purified acylated amino acid esters is accomplished by gas-liquid chromatographic techniques.

Novel poly-uridine insertion in the 3'UTR and E2 amino acid substitutions in a low virulent classical swine fever virus.

PubMed

Coronado, Liani; Liniger, Matthias; Muñoz-González, Sara; Postel, Alexander; Pérez, Lester Josue; Pérez-Simó, Marta; Perera, Carmen Laura; Frías-Lepoureau, Maria Teresa; Rosell, Rosa; Grundhoff, Adam; Indenbirken, Daniela; Alawi, Malik; Fischer, Nicole; Becher, Paul; Ruggli, Nicolas; Ganges, Llilianne

2017-03-01

In this study, we compared the virulence in weaner pigs of the Pinar del Rio isolate and the virulent Margarita strain. The latter caused the Cuban classical swine fever (CSF) outbreak of 1993. Our results showed that the Pinar del Rio virus isolated during an endemic phase is clearly of low virulence. We analysed the complete nucleotide sequence of the Pinar del Rio virus isolated after persistence in newborn piglets, as well as the genome sequence of the inoculum. The consensus genome sequence of the Pinar del Rio virus remained completely unchanged after 28days of persistent infection in swine. More importantly, a unique poly-uridine tract was discovered in the 3'UTR of the Pinar del Rio virus, which was not found in the Margarita virus or any other known CSFV sequences. Based on RNA secondary structure prediction, the poly-uridine tract results in a long single-stranded intervening sequence (SS) between the stem-loops I and II of the 3'UTR, without major changes in the stem- loop structures when compared to the Margarita virus. The possible implications of this novel insertion on persistence and attenuation remain to be investigated. In addition, comparison of the amino acid sequence of the viral proteins E rns , E1, E2 and p7 of the Margarita and Pinar del Rio viruses showed that all non-conservative amino acid substitutions acquired by the Pinar del Rio isolate clustered in E2, with two of them being located within the B/C domain. Immunisation and cross-neutralisation experiments in pigs and rabbits suggest differences between these two viruses, which may be attributable to the amino acid differences observed in E2. Altogether, these data provide fresh insights into viral molecular features which might be associated with the attenuation and adaptation of CSFV for persistence in the field. Copyright © 2017 Elsevier B.V. All rights reserved.

Enteroendocrine-derived glucagon-like peptide-2 controls intestinal amino acid transport.

PubMed

Lee, Jennifer; Koehler, Jacqueline; Yusta, Bernardo; Bahrami, Jasmine; Matthews, Dianne; Rafii, Mahroukh; Pencharz, Paul B; Drucker, Daniel J

2017-03-01

Glucagon-like peptide-2 (GLP-2) is co-secreted with GLP-1 from gut endocrine cells, and both peptides act as growth factors to expand the surface area of the mucosal epithelium. Notably, GLP-2 also enhances glucose and lipid transport in enterocytes; however, its actions on control of amino acid (AA) transport remain unclear. Here we examined the mechanisms linking gain and loss of GLP-2 receptor (GLP-2R) signaling to control of intestinal amino acid absorption in mice. Absorption, transport, and clearance of essential AAs, specifically lysine, were measured in vivo by Liquid Chromatography triple quadrupole Mass Spectrometry (LC-MS/MS) and ex vivo with Ussing chambers using intestinal preparations from Glp2 r +/+ and Glp2r - / - mice. Immunoblotting determined jejunal levels of protein components of signaling pathways (PI3K-AKT, and mTORC1-pS6-p4E-BP1) following administration of GLP-2, protein gavage, and rapamycin to fasted Glp2 r +/+ and Glp2r - / - mice. Expression of AA transporters from full thickness jejunum and 4F2hc from brush border membrane vesicles (BBMVs) was measured by real-time PCR and immunoblotting, respectively. Acute administration of GLP-2 increased basal AA absorption in vivo and augmented basal lysine transport ex vivo . GLP-2-stimulated lysine transport was attenuated by co-incubation with wortmannin, rapamycin, or tetrodotoxin ex vivo . Phosphorylation of mTORC1 effector proteins S6 and 4E-BP1 was significantly increased in wild-type mice in response to GLP-2 alone, or when co-administered with protein gavage, and abolished following oral gavage of rapamycin. In contrast, activation of GLP-1R signaling did not enhance S6 phosphorylation. Disruption of GLP-2 action in Glp2r -/- mice reduced lysine transport ex vivo and attenuated the phosphorylation of S6 and 4E-BP1 in response to oral protein. Moreover, the expression of cationic AA transporter slc7a9 in response to refeeding, and the abundance of 4F2hc in BBMVs following protein

Molecular characteristics of mammalian and insect amino acid transporters: implications for amino acid homeostasis.

PubMed

Castagna, M; Shayakul, C; Trotti, D; Sacchi, V F; Harvey, W R; Hediger, M A

1997-01-01

In mammalian cells, the uptake of amino acids is mediated by specialized, energy-dependent and passive transporters with overlapping substrate specificities. Most energy-dependent transporters are coupled either to the cotransport of Na+ or Cl- or to the countertransport of K+. Passive transporters are either facilitated transporters or channels. As a prelude to the molecular characterization of the different classes of transporters, we have isolated transporter cDNAs by expression-cloning with Xenopus laevis oocytes and we have characterized the cloned transporters functionally by uptake studies into oocytes using radiolabelled substrates and by electrophysiology to determine substrate-evoked currents. Mammalian transporters investigated include the dibasic and neutral amino acid transport protein D2/NBAT (system b0+) and the Na(+)- and K(+)-dependent neuronal and epithelial high-affinity glutamate transporter EAAC1 (system XAG-). A detailed characterization of these proteins has provided new information on transport characteristics and mechanisms for coupling to different inorganic ions. This work has furthermore advanced our understanding of the roles these transporters play in amino acid homeostasis and in various pathologies. For example, in the central nervous system, glutamate transporters are critically important in maintaining the extracellular glutamate concentration below neurotoxic levels, and defects of the human D2 gene have been shown to account for the formation of kidney stones in patients with cystinuria. Using similar approaches, we are investigating the molecular characteristics of K(+)-coupled amino acid transporters in the larval lepidopteran insect midgut. In the larval midgut, K+ is actively secreted into the lumen through the concerted action of an apical H+ V-ATPase and an apical K+/2H+ antiporter, thereby providing the driving force for absorption of amino acids. In vivo, the uptake occurs at extremely high pH (pH 10) and is driven by a

Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Aubrey, Andrew D.; Callahan, Michael P.; Dworkin, Jason P.; Elsila, Jamie E.; Parker, Eric T.; Bada, Jeffrey L.

2010-01-01

Amino acid analysis of a meteorite fragment of asteroid 2008 TC3 called Almahata Sitta was carried out using reverse-phase liquid chromatography coupled with UV fluorescence detection and time-of-flight mass spectrometry (LC-FD/ToF-MS) as part of a sample analysis consortium. LC-FD/ToF-MS analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to seven-carbon aliphatic amino acids and one- to three-carbon amines with abundances ranging from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, R-amino-n-butyric acid (beta-ABA), 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L approximately 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other non-protein amino acids were also identified in the meteorite above background levels including alpha-aminoisobutyric acid (alpha-AIB), 4-amino-2- methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and alpha-AIB in Almahata Sitta are 1000 times lower than the abundances of these amino acids found in the CM carbonaceous chondrite Murchison. The extremely low abundances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous chondrites may reflect extensive thermal alteration of amino acids on the parent asteroid by partial melting during formation or subsequent impact shock heating. It is also possible that amino acids were synthesized by catalytic reactions on the parent body after asteroid 2008 TC3 cooled to lower temperatures.

Nonprotein Amino Acids in the Murchison Meteorite

PubMed Central

Kvenvolden, Keith A.; Lawless, James G.; Ponnamperuma, Cyril

1971-01-01

Twelve nonprotein amino acids appear to be present in the Murchison meteorite. The identity of eight of them has been conclusively established as N-methylglycine, β-alanine, 2-methylalanine, α-amino-n-butyric acid, β-amino-n-butyric acid, γ-amino-n-butyric acid, isovaline, and pipecolic acid. Tentative evidence is presented for the presence of N-methylalanine, N-ethylglycine, β-aminoisobutyric acid, and norvaline. These amino acids appear to be extraterrestrial in origin and may provide new evidence for the hypothesis of chemical evolution. PMID:16591908

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

Primary amino acid derivatives: substitution of the 4'-N'-benzylamide site in (R)-N'-benzyl 2-amino-3-methylbutanamide, (R)-N'-benzyl 2-amino-3,3-dimethylbutanamide, and (R)-N'-benzyl 2-amino-3-methoxypropionamide provides potent anticonvulsants with pain-attenuating properties.

PubMed

King, Amber M; Salomé, Christophe; Salomé-Grosjean, Elise; De Ryck, Marc; Kaminski, Rafal; Valade, Anne; Stables, James P; Kohn, Harold

2011-10-13

Recently, we reported that select N'-benzyl 2-substituted 2-amino acetamides (primary amino acid derivatives (PAADs)) exhibited pronounced activities in established whole animal anticonvulsant (i.e., maximal electroshock seizure (MES)) and neuropathic pain (i.e., formalin) models. The anticonvulsant activities of C(2)-hydrocarbon N'-benzyl 2-amino acetamides (MES ED(50) = 13-21 mg/kg) exceeded those of phenobarbital (ED(50) = 22 mg/kg). Two additional studies defining the structure-activity relationship of PAADs are presented in this issue of the journal. In this study, we demonstrated that the anticonvulsant activities of (R)-N'-benzyl 2-amino-3-methylbutanamide and (R)-N'-benzyl 2-amino-3,3-dimethylbutanamide were sensitive to substituents at the 4'-N'-benzylamide site; electron-withdrawing groups retained activity, electron-donating groups led to a loss of activity, and incorporating either a 3-fluorobenzyloxy or 3-fluorophenoxymethyl group using a rationally designed multiple ligand approach improved activity. Additionally, we showed that substituents at the 4'-N'-benzylamide site of (R)-N'-benzyl 2-amino-3-methoxypropionamide also improved anticonvulsant activity, with the 3-fluorophenoxymethyl group providing the largest (∼4-fold) increase in activity (ED(50) = 8.9 mg/kg), a value that surpassed phenytoin (ED(50) = 9.5 mg/kg). Collectively, the pharmacological findings provided new information that C(2)-hydrocarbon PAADs represent a novel class of anticonvulsants.

Influence of Murchison Minerals on Hydrogen-Deuterium Exchange of Amino Acids

NASA Astrophysics Data System (ADS)

Lerner, N. R.

1993-07-01

C and 155 degrees C in solutions containing Murchison dust. For both glycine and alanine the activation energy is -25 kcal/mole. Using this value, we have calculated the half-lives for complete exchange of the alpha-hydrogens of glycine and alanine for the temperature range thought to have existed on the parent body during aqueous alteration [5]. The half-lives at 0 degrees C and 20 degrees C are 7500 yr and 300 yr respectively for glycine and 55,000 yr and 2100 yr respectively for alanine. Murchison amino acid fraction IV [1] was known to contain impurities and hence the measured delta D value represents a lower limit for alpha-amino isobutyric acid. Assuming that all the deuterium recovered from fraction IV came from alpha-amino isobutryric acid, and that one atom of nitrogen is recovered for each molecule of alpha-amino isobutyric acid, a maximum delta D value of +2600 per mil can be calculated for this amino acid. This is comparable to delta D for the glycine-alanine fraction, which is mainly glycine [6]. In an aqueous environment glycine loses deuterium relatively rapidly while alpha-amino isobutyric acid does not undergo exchange. Hence the similarity in the delta D values of both fractions indicates that the period of aqueous alteration is less than the half-life for hydrogen-deuterium exchange of glycine. References: [1] Pizzarello S. et al. (1991) GCA, 55, 905-910. [2] Zinner E. (1988) In Meteorites and the Early Solar System (J. R. Kerridge and M. S. Matthews, eds.), 956-983, Univ. of Arizona. [3] Lerner N. R. et al. (1993) GCA, in press. [4] Bunch T. E. and Chang S. (1980) GCA, 44, 1543-1577. [5] Clayton R. N. and Mayeda T. K. (1984) EPSL, 67, 151-161. [6] Shock E. L. and Shulte M. D. (1990) GCA, 54, 3159-3173.

Amino acids derived from Titan tholins

NASA Technical Reports Server (NTRS)

Khare, B. N.; Sagan, C.; Ogino, H.; Nagy, B.; Er, C.; Schram, K. H.; Arakawa, E. T.

1986-01-01

An organic heteropolymer (Titan tholin) was produced by continuous dc discharge through a 0.9 N2/0.1 CH4 gas mixture at 0.2 mbar pressure, roughly simulating the cloudtop atmosphere of Titan. Treatment of this tholin with 6N HCl yielded 16 amino acids by gas chromatography after derivatization of N-trifluroacetyl isopropyl esters on two different capillary columns. Identifications were confirmed by GC/MS. Glycine, aspartic acid, and alpha- and beta-alanine were produced in greatest abundance; the total yield of amino acids was approximately 10(-2), approximately equal to the yield of urea. The presence of "nonbiological" amino acids, the absence of serine, and the fact that the amino acids are racemic within experimental error together indicate that these molecules are not due to microbial or other contamination, but are derived from the tholin. In addition to the HCN, HC2CN, and (CN)2 found by Voyager, nitriles and aminonitriles should be sought in the Titanian atmosphere and, eventually, amino acids on the surface. These results suggest that episodes of liquid water in the past or future of Titan might lead to major further steps in prebiological organic chemistry on that body.

Amino acid composition of some Mexican foods.

PubMed

Morales de León, Josefina; Camacho, M Elena; Bourges, Héctor

2005-06-01

Knowledge of the amino acid composition of foods is essential to calculate their chemical score, which is used to predict protein quality of foods and diets. Though amino acid composition of many foods is reasonably well established, better knowledge is needed on native foods consumed in different regions and countries. This paper presents the amino acid composition of different presentations of raw and processed foods produced and consumed in Mexico. The amino acid composition was determined using Beckman amino acid analyzers (models 116 and 6300). Tryptophan was determined using the Spies and Chambers method. Of the different foods analyzed, some comments are made on native or basic foods in Mexico: Spirulin, where lysine is the limiting amino acid, with a chemical score of 67%, is a good source of tryptophan (1.16g/16 gN); amaranth contains high levels of sulphur amino acids (4.09 to 5.34 g/16gN), with a protein content of 15 g/100g; and pulque, a Pre-Hispanic beverage that contains high levels of tryptophan (2.58 g/16 gN) and sulphur amino acids (2.72 g/16 gN). Finally, insects are good sources of sulphur amino acids and lysine.

Glutamic Acid – the Main Dietary Amino Acid – and Blood Pressure: The INTERMAP Study

PubMed Central

Stamler, Jeremiah; Brown, Ian J; Daviglus, Martha L; Chan, Queenie; Kesteloot, Hugo; Ueshima, Hirotsugu; Zhao, Liancheng; Elliott, Paul

2009-01-01

Background Data are available indicating an independent inverse relationship of dietary vegetable protein to the blood pressure (BP) of individuals. Here we assess whether BP is associated with glutamic acid intake (the predominant dietary amino acid, especially in vegetable protein) and with each of four other amino acids higher relatively in vegetable than animal protein (proline, phenylalanine, serine, cystine). Methods and Results Cross-sectional epidemiological study; 4,680 persons ages 40–59 -- 17 random population samples in China, Japan, U.K., U.S.A.; BP measurement 8 times at 4 visits; dietary data (83 nutrients, 18 amino acids) from 4 standardized multi-pass 24-hour dietary recalls and 2 timed 24-hour urine collections. Dietary glutamic acid (percent of total protein intake) was inversely related to BP. Across multivariate regression models (Model 1 controlled for age, gender, sample, through Model 5 controlled for 16 non-nutrient and nutrient possible confounders) estimated average BP differences associated with glutamic acid intake higher by 4.72% total dietary protein (2 s.d.) were −1.5 to −3.0 mm Hg systolic and −1.0 to −1.6 mm Hg diastolic (Z-values −2.15 to −5.11). Results were similar for the glutamic acid-BP relationship with each other amino acid also in the model, e.g., with control for 15 variables plus proline, systolic/diastolic pressure differences −2.7/−2.0 (Z −2.51, −2.82). In these 2-amino acid models, higher intake (2 s.d.) of each other amino acid was associated with small BP differences and Z-values. Conclusions Dietary glutamic acid may have independent BP lowering effects, possibly contributing to the inverse relation of vegetable protein to BP. PMID:19581495

Formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations - A review.

PubMed

Zhao, Cindy J; Schieber, Andreas; Gänzle, Michael G

2016-11-01

Fermented foods are valued for their rich and complex odour and taste. The metabolic activity of food-fermenting microorganisms determines food quality and generates odour and taste compounds. This communication reviews the formation of taste-active amino acids, amino acid derivatives and peptides in food fermentations. Pathways of the generation of taste compounds are presented for soy sauce, cheese, fermented meats, and bread. Proteolysis or autolysis during food fermentations generates taste-active amino acids and peptides; peptides derived from proteolysis particularly impart umami taste (e.g. α-glutamyl peptides) or bitter taste (e.g. hydrophobic peptides containing proline). Taste active peptide derivatives include pyroglutamyl peptides, γ-glutamyl peptides, and succinyl- or lactoyl amino acids. The influence of fermentation microbiota on proteolysis, and peptide hydrolysis, and the metabolism of glutamate and arginine is well understood, however, the understanding of microbial metabolic activities related to the formation of taste-active peptide derivatives is incomplete. Improved knowledge of the interactions between taste-active compounds will enable the development of novel fermentation strategies to develop tastier, less bitter, and low-salt food products, and may provide novel and "clean label" ingredients to improve the taste of other food products. Copyright © 2016 Elsevier Ltd. All rights reserved.

Regulation of protein synthesis by amino acids in muscle of neonates

PubMed Central

Suryawan, Agus; Davis, Teresa A.

2011-01-01

The marked increase in skeletal muscle mass during the neonatal period is largely due to a high rate of postprandial protein synthesis that is modulated by an enhanced sensitivity to insulin and amino acids. The amino acid signaling pathway leading to the stimulation of protein synthesis has not been fully elucidated. Among the amino acids, leucine is considered to be a principal anabolic agent that regulates protein synthesis. mTORC1, which controls protein synthesis, has been implicated as a target for leucine. Until recently, there have been few studies exploring the role of amino acids in enhancing muscle protein synthesis in vivo. In this review, we discuss amino acid-induced protein synthesis in muscle in the neonate, focusing on current knowledge of the role of amino acids in the activation of mTORC1 leading to mRNA translation. The role of the amino acid transporters, SNAT2, LAT1, and PAT, in the modulation of mTORC1 activation and the role of amino acids in the activation of putative regulators of mTORC1, i.e., raptor, Rheb, MAP4K3, Vps34, and Rag GTPases, are discussed. PMID:21196241

Akt-dependent Activation of the Heart 6-Phosphofructo-2-kinase/Fructose-2,6-bisphosphatase (PFKFB2) Isoenzyme by Amino Acids*

PubMed Central

Novellasdemunt, Laura; Tato, Irantzu; Navarro-Sabate, Aurea; Ruiz-Meana, Marisol; Méndez-Lucas, Andrés; Perales, Jose Carlos; Garcia-Dorado, David; Ventura, Francesc; Bartrons, Ramon; Rosa, Jose Luis

2013-01-01

Reciprocal regulation of metabolism and signaling allows cells to modulate their activity in accordance with their metabolic resources. Thus, amino acids could activate signal transduction pathways that control cell metabolism. To test this hypothesis, we analyzed the effect of amino acids on fructose-2,6-bisphosphate (Fru-2,6-P2) metabolism. We demonstrate that amino acids increase Fru-2,6-P2 concentration in HeLa and in MCF7 human cells. In conjunction with this, 6-phosphofructo-2-kinase activity, glucose uptake, and lactate concentration were increased. These data correlate with the specific phosphorylation of heart 6-phosphofructo-2-kinase/fructose-2,6-biphosphatase (PFKFB2) isoenzyme at Ser-483. This activation was mediated by the PI3K and p38 signaling pathways. Furthermore, Akt inactivation blocked PFKFB2 phosphorylation and Fru-2,6-P2 production, thereby suggesting that the above signaling pathways converge at Akt kinase. In accordance with these results, kinase assays showed that amino acid-activated Akt phosphorylated PFKFB2 at Ser-483 and that knockdown experiments confirmed that the increase in Fru-2,6-P2 concentration induced by amino acids was due to PFKFB2. In addition, similar effects on Fru-2,6-P2 metabolism were observed in freshly isolated rat cardiomyocytes treated with amino acids, which indicates that these effects are not restricted to human cancer cells. In these cardiomyocytes, the glucose consumption and the production of lactate and ATP suggest an increase of glycolytic flux. Taken together, these results demonstrate that amino acids stimulate Fru-2,6-P2 synthesis by Akt-dependent PFKFB2 phosphorylation and activation and show how signaling and metabolism are inextricably linked. PMID:23457334

Biosensors for D-amino acid detection.

PubMed

Sacchi, Silvia; Rosini, Elena; Caldinelli, Laura; Pollegioni, Loredano

2012-01-01

The presence of D-amino acids in foods is promoted by harsh technological processes (e.g., high temperature or extreme pH values) or can be the consequence of adulteration or microbial contamination (D-amino acids are major components of the bacterial cell wall). For this reason, quality control is becoming more and more important both for the industry (as a cost factor) and for consumer protection. For routine food analysis and quality control, simple and easily applicable analytical methods are needed: biosensors can often satisfy these requirements. The use of an enzymatic, stereospecific reaction could confer selectivity to a biosensor for detecting and quantifying D-amino acids in foodstuffs. The flavoenzyme D-amino acid oxidase from the yeast Rhodotorula gracilis is an ideal biocatalyst for this kind of application because of its absolute stereospecificity, very high turnover number with various substrates, tight binding with the FAD cofactor, and broad substrate specificity. Furthermore, alterations in the local brain concentrations of D-serine (predominantly D-amino acid in the mammalian central nervous system) have been related to several neurological and psychiatric diseases. Therefore, quantifying this neuromodulator represents an important task in biological, medical, and pharmaceutical research. Recently, an enzymatic microbiosensor, also using R. gracilis D-amino acid oxidase as biocatalyst, was developed for detecting D-serine in vivo.

Synthesis and conformational analysis of hybrid α/β-dipeptides incorporating S-glycosyl-β(2,2)-amino acids.

PubMed

García-González, Iván; Mata, Lara; Corzana, Francisco; Jiménez-Osés, Gonzalo; Avenoza, Alberto; Busto, Jesús H; Peregrina, Jesús M

2015-01-12

We synthesized and carried out the conformational analysis of several hybrid dipeptides consisting of an α-amino acid attached to a quaternary glyco-β-amino acid. In particular, we combined a S-glycosylated β(2,2)-amino acid and two different types of α-amino acid, namely, aliphatic (alanine) and aromatic (phenylalanine and tryptophan) in the sequence of hybrid α/β-dipeptides. The key step in the synthesis involved the ring-opening reaction of a chiral cyclic sulfamidate, inserted in the peptidic sequence, with a sulfur-containing nucleophile by using 1-thio-β-D-glucopyranose derivatives. This reaction of glycosylation occurred with inversion of configuration at the quaternary center. The conformational behavior in aqueous solution of the peptide backbone and the glycosidic linkage for all synthesized hybrid glycopeptides was analyzed by using a protocol that combined NMR experiments and molecular dynamics with time-averaged restraints (MD-tar). Interestingly, the presence of the sulfur heteroatom at the quaternary center of the β-amino acid induced θ torsional angles close to 180° (anti). Notably, this value changed to 60° (gauche) when the peptidic sequence displayed aromatic α-amino acids due to the presence of CH-π interactions between the phenyl or indole ring and the methyl groups of the β-amino acid unit. © 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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.

Benzylserine inhibits breast cancer cell growth by disrupting intracellular amino acid homeostasis and triggering amino acid response pathways.

PubMed

van Geldermalsen, Michelle; Quek, Lake-Ee; Turner, Nigel; Freidman, Natasha; Pang, Angel; Guan, Yi Fang; Krycer, James R; Ryan, Renae; Wang, Qian; Holst, Jeff

2018-06-26

Cancer cells require increased levels of nutrients such as amino acids to sustain their rapid growth. In particular, leucine and glutamine have been shown to be important for growth and proliferation of some breast cancers, and therefore targeting the primary cell-surface transporters that mediate their uptake, L-type amino acid transporter 1 (LAT1) and alanine, serine, cysteine-preferring transporter 2 (ASCT2), is a potential therapeutic strategy. The ASCT2 inhibitor, benzylserine (BenSer), is also able to block LAT1 activity, thus inhibiting both leucine and glutamine uptake. We therefore aimed to investigate the effects of BenSer in breast cancer cell lines to determine whether combined LAT1 and ASCT2 inhibition could inhibit cell growth and proliferation. BenSer treatment significantly inhibited both leucine and glutamine uptake in MCF-7, HCC1806 and MDA-MB-231 breast cancer cells, causing decreased cell viability and cell cycle progression. These effects were not primarily leucine-mediated, as BenSer was more cytostatic than the LAT family inhibitor, BCH. Oocyte uptake assays with ectopically expressed amino acid transporters identified four additional targets of BenSer, and gas chromatography-mass spectrometry (GCMS) analysis of intracellular amino acid concentrations revealed that this BenSer-mediated inhibition of amino acid uptake was sufficient to disrupt multiple pathways of amino acid metabolism, causing reduced lactate production and activation of an amino acid response (AAR) through activating transcription factor 4 (ATF4). Together these data showed that BenSer blockade inhibited breast cancer cell growth and viability through disruption of intracellular amino acid homeostasis and inhibition of downstream metabolic and growth pathways.

2-Chlorotrityl chloride resin. Studies on anchoring of Fmoc-amino acids and peptide cleavage.

PubMed

Barlos, K; Chatzi, O; Gatos, D; Stavropoulos, G

1991-06-01

The esterification of 2-chlorotrityl chloride resin with Fmoc-amino acids in the presence of DIEA is studied under various conditions. High esterification yields are obtained using 0.6 equiv. Fmoc-amino acid/mmol resin in DCM or DCE, in 25 min, at room temperature. The reaction proceeds without by product formation even in the case of Fmoc-Asn and Fmoc-Gln. The quantitative and easy cleavage of amino acids and peptides from 2-chlorotrityl resin, by using AcOH/TFE/DCM mixtures, is accomplished within 15-60 min at room temperature, while t-butyl type protecting groups remain unaffected. Under these exceptionally mild conditions 2-chlorotrityl cations generated during the cleavage of amino acids and peptides from resin do not attack the nucleophilic side chains of Trp, Met, and Tyr.

Hyperglucagonemia correlates with plasma levels of non-branched-chain amino acids in patients with liver disease independent of type 2 diabetes.

PubMed

Wewer Albrechtsen, Nicolai J; Junker, Anders E; Christensen, Mette; Hædersdal, Sofie; Wibrand, Flemming; Lund, Allan M; Galsgaard, Katrine D; Holst, Jens J; Knop, Filip K; Vilsbøll, Tina

2018-01-01

Patients with type 2 diabetes (T2D) and patients with nonalcoholic fatty liver disease (NAFLD) frequently exhibit elevated plasma concentrations of glucagon (hyperglucagonemia). Hyperglucagonemia and α-cell hyperplasia may result from elevated levels of plasma amino acids when glucagon's action on hepatic amino acid metabolism is disrupted. We therefore measured plasma levels of glucagon and individual amino acids in patients with and without biopsy-verified NAFLD and with and without type T2D. Fasting levels of amino acids and glucagon in plasma were measured, using validated ELISAs and high-performance liquid chromatography, in obese, middle-aged individuals with I) normal glucose tolerance (NGT) and NAFLD, II) T2D and NAFLD, III) T2D without liver disease, and IV) NGT and no liver disease. Elevated levels of total amino acids were observed in participants with NAFLD and NGT compared with NGT controls (1,310 ± 235 µM vs. 937 ± 281 µM, P = 0.03) and in T2D and NAFLD compared with T2D without liver disease (1,354 ± 329 µM vs. 511 ± 235 µM, P < 0.0001). Particularly amino acids with known glucagonotropic effects (e.g., glutamine) were increased. Plasma levels of total amino acids correlated to plasma levels of glucagon also when adjusting for body mass index (BMI), glycated hemoglobin (Hb A1c ), and cholesterol levels (β = 0.013 ± 0.007, P = 0.024). Elevated plasma levels of total amino acids associate with hyperglucagonemia in NAFLD patients independently of glycemic control, BMI or cholesterol - supporting the potential importance of a "liver-α-cell axis" in which glucagon regulates hepatic amino acid metabolism. Fasting hyperglucagonemia as seen in T2D may therefore represent impaired hepatic glucagon action with increasing amino acids levels. NEW & NOTEWORTHY Hypersecretion of glucagon (hyperglucagonemia) has been suggested to be linked to type 2 diabetes. Here, we show that levels of amino acids correlate with levels of

40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl)ethoxy] ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo], trisodium salt. 721.5260 Section 721.5260 Protection of Environment...

40 CFR 721.5260 - 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 1,3,6-Naphthalenetrisulfonic acid, 7-[[2-[(aminocarbonyl)amino]- 4-[[4-[[2-[2-(ethenylsulfonyl)ethoxy] ethyl]amino]- 6-fluoro-1,3,5-triazin-2-yl]amino]phenyl]azo], trisodium salt. 721.5260 Section 721.5260 Protection of Environment...

Amino acids and sport: a true love story?

PubMed

Goron, Arthur; Moinard, Christophe

2018-05-31

Among a plethora of dietary supplements, amino acids are very popular with athletes for several reasons (e.g., to prevent nutritional deficiency, improve muscle function, and decrease muscle damages) whose purpose is to improve performance. However, it is difficult to get a clear idea of which amino acids have real ergogenic impact. Here, we review and analyze the clinical studies evaluating specific amino acids (glutamine, arginine, leucine, etc.) in athletes. Only english-language clinical studies evaluating a specific effect of one amino acid were considered. Despite promising results, many studies have methodological limits or specific flaws that do not allow definitive conclusions. To date, only chronic β-alanine supplementation demonstrated an ergogenic effect in athletes. Much research is still needed to gain evidence-based data before any other specific amino acid can be recommended for use in athletes.

Microbial degradation of poly(amino acid)s.

PubMed

Obst, Martin; Steinbüchel, Alexander

2004-01-01

Natural poly(amino acid)s are a group of poly(ionic) molecules (ionomers) with various biological functions and putative technical applications and play, therefore, an important role both in nature and in human life. Because of their biocompatibility and their synthesis from renewable resources, poly(amino acid)s may be employed for many different purposes covering a broad spectrum of medical, pharmaceutical, and personal care applications as well as the domains of agriculture and of environmental applications. Biodegradability is one important advantage of naturally occurring poly(amino acid)s over many synthetic polymers. The intention of this review is to give an overview about the enzyme systems catalyzing the initial steps in poly(amino acid) degradation. The focus is on the naturally occurring poly(amino acid)s cyanophycin, poly(epsilon-L-lysine) and poly(gamma-glutamic acid); but biodegradation of structurally related synthetic polyamides such as poly(aspartic acid) and nylons, which are known from various technical applications, is also included.

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.

Plasma amino acid and metabolite signatures tracking diabetes progression in the UCD-T2DM rat model

PubMed Central

Piccolo, Brian D.; Graham, James L.; Stanhope, Kimber L.; Fiehn, Oliver; Havel, Peter J.

2016-01-01

Elevations of plasma concentrations of branched-chain amino acids (BCAAs) are observed in human insulin resistance and type 2 diabetes mellitus (T2DM); however, there has been some controversy with respect to the passive or causative nature of the BCAA phenotype. Using untargeted metabolomics, plasma BCAA and other metabolites were assessed in lean control Sprague-Dawley rats (LC) and temporally during diabetes development in the UCD-T2DM rat model, i.e., prediabetic (PD) and 2 wk (D2W), 3 mo (D3M), and 6 mo (D6M) post-onset of diabetes. Plasma leucine, isoleucine, and valine concentrations were elevated only in D6M rats compared with D2W rats (by 28, 29, and 30%, respectively). This was in contrast to decreased plasma concentrations of several other amino acids in D3M and/or D6M relative to LC rats (Ala, Arg, Glu, Gln, Met, Ser, Thr, and Trp). BCAAs were positively correlated with fasting glucose and negatively correlated with plasma insulin, total body weight, total adipose tissue weight, and gastrocnemius muscle weight in the D3M and D6M groups. Multivariate analysis revealed that D3M and D6M UCD-T2DM rats had lower concentrations of amino acids, amino acid derivatives, 1,5-anhydroglucitol, and conduritol-β-opoxide and higher concentrations of uronic acids, pantothenic acids, aconitate, benzoic acid, lactate, and monopalmitin-2-glyceride relative to PD and D2W UCD-T2DM rats. The UCD-T2DM rat does not display elevated plasma BCAA concentrations until 6 mo post-onset of diabetes. With the acknowledgement that this is a rodent model of T2DM, the results indicate that elevated plasma BCAA concentrations are not necessary or sufficient to elicit an insulin resistance or T2DM onset. PMID:27094034

Fmoc/Trt-amino acids: comparison to Fmoc/tBu-amino acids in peptide synthesis.

PubMed

Barlos, K; Gatos, D; Koutsogianni, S

1998-03-01

Model peptides containing the nucleophilic amino acids Trp and Met have been synthesized with the application of Fmoc/Trt- and Fmoc/tBu-amino acids, for comparison. The deprotection of the peptides synthesized using Fmoc/Trt-amino acids in all cases leads to crude peptides of higher purity than that of the same peptides synthesized using Fmoc/tBu-amino acids.

Genetically encoded fluorescent coumarin amino acids

DOEpatents

Wang, Jiangyun; Xie, Jianming; Schultz, Peter G.

2010-10-05

The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl) ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.

Genetically encoded fluorescent coumarin amino acids

DOEpatents

Wang, Jiangyun [San Diego, CA; Xie, Jianming [San Diego, CA; Schultz, Peter G [La Jolla, CA

2012-06-05

The invention relates to orthogonal pairs of tRNAs and aminoacyl-tRNA synthetases that can incorporate the coumarin unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine into proteins produced in eubacterial host cells such as E. coli. The invention provides, for example but not limited to, novel orthogonal synthetases, methods for identifying and making the novel synthetases, methods for producing proteins containing the unnatural amino acid L-(7-hydroxycoumarin-4-yl)ethylglycine and related translation systems.

Amino Acid Transporters and Release of Hydrophobic Amino Acids in the Heterocyst-Forming Cyanobacterium Anabaena sp. Strain PCC 7120.

PubMed

Pernil, Rafael; Picossi, Silvia; Herrero, Antonia; Flores, Enrique; Mariscal, Vicente

2015-04-23

Anabaena sp. strain PCC 7120 is a filamentous cyanobacterium that can use inorganic compounds such as nitrate or ammonium as nitrogen sources. In the absence of combined nitrogen, it can fix N2 in differentiated cells called heterocysts. Anabaena also shows substantial activities of amino acid uptake, and three ABC-type transporters for amino acids have been previously characterized. Seven new loci encoding predicted amino acid transporters were identified in the Anabaena genomic sequence and inactivated. Two of them were involved in amino acid uptake. Locus alr2535-alr2541 encodes the elements of a hydrophobic amino acid ABC-type transporter that is mainly involved in the uptake of glycine. ORF all0342 encodes a putative transporter from the dicarboxylate/amino acid:cation symporter (DAACS) family whose inactivation resulted in an increased uptake of a broad range of amino acids. An assay to study amino acid release from Anabaena filaments to the external medium was set up. Net release of the alanine analogue α-aminoisobutyric acid (AIB) was observed when transport system N-I (a hydrophobic amino acid ABC-type transporter) was engaged in the uptake of a specific substrate. The rate of AIB release was directly proportional to the intracellular AIB concentration, suggesting leakage from the cells by diffusion.

Prebiotic synthesis in atmospheres containing CH4, CO, and CO2. I - Amino acids

NASA Technical Reports Server (NTRS)

Schlesinger, G.; Miller, S. L.

1983-01-01

The prebiotic synthesis of amino acids, HCN, H2CO, and NH3 using a spark discharge on various simulated primitive earth atmospheres at 25 C is investigated. Various mixtures of CH4, CO, CO2, N2, NH3, H2O, and H2 were utilized in different experiments. The yields of amino acids (1.2-4.7 percent based on the carbon) are found to be approximately independent of the H2/CH4 ratio and the presence of NH3, and a wide variety of amino acids are obtained. Glycine is found to be almost the only amino acid produced from CO and CO2 model atmospheres, with the maximum yield being about the same for the three carbon sources at high H2/carbon ratios,whereas CH4 is superior at low H2/carbon ratios. In addition, it is found that the directly synthesized NH3 together with the NH3 obtained from the hydrolysis of HCN, nitriles, and urea could have been a major source of ammonia in the atmosphere and oceans of the primitive earth. It is determined that prebiotic syntheses from HCN and H2CO to give products such as purines and sugars and some amino acids could have occurred in primitive atmospheres containing CO and CO2 provided the H2/CO and H2/CO2 ratios were greater than about 1.0.

Enantiomer-specific selection of amino acids.

PubMed

Ren, Xueying; Tellez, Luis A; de Araujo, Ivan E

2013-12-01

Dietary intake of L-amino acids impacts on several physiological functions, including the control of gastrointestinal motility, pancreatic secretion, and appetite. However, the biological mechanisms regulating behavioral predilections for certain amino acid types remain poorly understood. We tested the hypothesis that, in mice, the potency with which a given glucogenic amino acid increases glucose utilization reflects its rewarding properties. We have found that: (1) during long-, but not short-, term preference tests, L-alanine and L-serine were preferred over their D-enantiomer counterparts, while no such effect was observed for L-threonine vs. D-threonine; (2) these behavioral patterns were closely associated with the ability of L-amino acids to promote increases in respiratory exchange ratios such that those, and only those, L-amino acids able to promote increases in respiratory exchange ratios were preferred over their D-isomers; (3) these behavioral preferences were independent of gustatory influences, since taste-deficient Trpm5 knockout mice displayed ingestive responses very similar to those of their wild-type counterparts. We conclude that the ability to promote increases in respiratory exchange ratios enhances the reward value of nutritionally relevant amino acids and suggest a mechanistic link between substrate utilization and amino acid preferences.

Enantiomer-specific selection of amino acids

PubMed Central

Ren, Xueying; Tellez, Luis A; de Araujo, Ivan E

2013-01-01

Dietary intake of L-amino acids impacts on several physiological functions, including the control of gastrointestinal motility, pancreatic secretion, and appetite. However, the biological mechanisms regulating behavioral predilections for certain amino acid types remain poorly understood. We tested the hypothesis that, in mice, the potency with which a given glucogenic amino acid increases glucose utilization reflects its rewarding properties. We have found that: 1. During long-, but not short-, term preference tests, L-alanine and L-serine were preferred over their D-enantiomer counterparts, while no such effect was observed for L-threonine vs. D-threonine; 2. These behavioral patterns were closely associated with the ability of L-amino acids to promote increases in respiratory exchange ratios such that those, and only those, L-amino acids able to promote increases in respiratory exchange ratios were preferred over their D-isomers; 3. These behavioral preferences were independent of gustatory influences, since taste-deficient Trpm5 knockout mice displayed ingestive responses very similar to those of their wild-type counterparts. We conclude that the ability to promote increases in respiratory exchange ratios enhances the reward value of nutritionally relevant amino acids, and suggest a mechanistic link between substrate utilization and amino acid preferences. PMID:24072505

Carbon Isotopic Ratios of Amino Acids in Stardust-Returned Samples

NASA Technical Reports Server (NTRS)

Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

2009-01-01

NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here. we present the carbon isotopic ratios of glycine and E-aminocaproic acid (EACH), the two most abundant amino acids observed, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio crass spectrometry coupled with quadrupole mass spectrometry (GC-QMS/IRMS).

Carbon Isotopic Measurements of Amino Acids in Stardust-Returned Samples

NASA Technical Reports Server (NTRS)

Elsila, Jamie

2009-01-01

NASA's Stardust spacecraft returned to Earth samples from comet 81P/Wild 2 in January 2006. Preliminary examinations revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds could not be identified. Here, we present the carbon isotopic ratios of glycine and e-aminocaproic acid (EACA), the two most abundant amino acids, in Stardust-returned foil samples measured by gas chromatography-combustion-isotope ratio mass spectrometry coupled with quadrupole mass spectrometry (GC-CAMS/IRMS).

Human Protein and Amino Acid Requirements.

PubMed

Hoffer, L John

2016-05-01

Human protein and amino acid nutrition encompasses a wide, complex, frequently misunderstood, and often contentious area of clinical research and practice. This tutorial explains the basic biochemical and physiologic principles that underlie our current understanding of protein and amino acid nutrition. The following topics are discussed: (1) the identity, measurement, and essentiality of nutritional proteins; (2) the definition and determination of minimum requirements; (3) nutrition adaptation; (4) obligatory nitrogen excretion and the minimum protein requirement; (5) minimum versus optimum protein intakes; (6) metabolic responses to surfeit and deficient protein intakes; (7) body composition and protein requirements; (8) labile protein; (9) N balance; (10) the principles of protein and amino acid turnover, including an analysis of the controversial indicator amino acid oxidation technique; (11) general guidelines for evaluating protein turnover articles; (12) amino acid turnover versus clearance; (13) the protein content of hydrated amino acid solutions; (14) protein requirements in special situations, including protein-catabolic critical illness; (15) amino acid supplements and additives, including monosodium glutamate and glutamine; and (16) a perspective on the future of protein and amino acid nutrition research. In addition to providing practical information, this tutorial aims to demonstrate the importance of rigorous physiologic reasoning, stimulate intellectual curiosity, and encourage fresh ideas in this dynamic area of human nutrition. In general, references are provided only for topics that are not well covered in modern textbooks. © 2016 American Society for Parenteral and Enteral Nutrition.

α-Amino Acid-Isosteric α-Amino Tetrazoles

PubMed Central

Zhao, Ting; Kurpiewska, Katarzyna; Kalinowska-Tłuścik, Justyna; Herdtweck, Eberhardt

2016-01-01

The synthesis of all 20 common natural proteinogenic and 4 otherα-amino acid-isosteric α-amino tetrazoles has been accomplished, whereby the carboxyl group is replaced by the isosteric 5-tetrazolyl group. The short process involves the use of the key Ugi tetrazole reaction followed by deprotection chemistries. The tetrazole group is bioisosteric to the carboxylic acid and is widely used in medicinal chemistry and drug design. Surprisingly, several of the common α-amino acid-isosteric α-amino tetrazoles are unknown up to now. Therefore a rapid synthetic access to this compound class and non-natural derivatives is of high interest to advance the field. PMID:26817531

The delta-subunit of murine guanine nucleotide exchange factor eIF-2B. Characterization of cDNAs predicts isoforms differing at the amino-terminal end.

PubMed

Henderson, R A; Krissansen, G W; Yong, R Y; Leung, E; Watson, J D; Dholakia, J N

1994-12-02

Protein synthesis in mammalian cells is regulated at the level of the guanine nucleotide exchange factor, eIF-2B, which catalyzes the exchange of eukaryotic initiation factor 2-bound GDP for GTP. We have isolated and sequenced cDNA clones encoding the delta-subunit of murine eIF-2B. The cDNA sequence encodes a polypeptide of 544 amino acids with molecular mass of 60 kDa. Antibodies against a synthetic polypeptide of 30 amino acids deduced from the cDNA sequence specifically react with the delta-subunit of mammalian eIF-2B. The cDNA-derived amino acid sequence shows significant homology with the yeast translational regulator Gcd2, supporting the hypothesis that Gcd2 may be the yeast homolog of the delta-subunit of mammalian eIF-2B. Primer extension studies and anchor polymerase chain reaction analysis were performed to determine the 5'-end of the transcript for the delta-subunit of eIF-2B. Results of these experiments demonstrate two different mRNAs for the delta-subunit of eIF-2B in murine cells. The isolation and characterization of two different full-length cDNAs also predicts the presence of two alternate forms of the delta-subunit of eIF-2B in murine cells. These differ at their amino-terminal end but have identical nucleotide sequences coding for amino acids 31-544.

Impact of charged amino acid substitution in the transmembrane domain of L-alanine exporter, AlaE, of Escherichia coli on the L-alanine export.

PubMed

Kim, Seryoung; Ihara, Kohei; Katsube, Satoshi; Ando, Tasuke; Isogai, Emiko; Yoneyama, Hiroshi

2017-01-01

The Escherichia coli alaE gene encodes the L-alanine exporter, AlaE, that catalyzes active export of L-alanine using proton electrochemical potential. The transporter comprises only 149 amino acid residues and four predicted transmembrane domains (TMs), which contain three charged amino acid residues. The AlaE-deficient L-alanine non-metabolizing cells (ΔalaE cells) appeared hypersusceptible to L-alanyl-L-alanine showing a minimum inhibitory concentration (MIC) of 2.5 µg/ml for the dipeptide due to a toxic accumulation of L-alanine. To elucidate the mechanism by which AlaE exports L-alanine, we replaced charged amino acid residues in the TMs, glutamic acid-30 (TM-I), arginine-45 (TM-II), and aspartic acid-84 (TM-III) with their respective charge-conserved amino acid or a net neutral cysteine. The ΔalaE cells producing R45K or R45C appeared hypersusceptible to the dipeptide, indicating that arginine-45 is essential for AlaE activity. MIC of the dipeptide in the ΔalaE cells expressing E30D and E30C was 156 µg/ml and >10,000 µg/ml, respectively, thereby suggesting that a negative charge at this position is not essential. The ΔalaE cells expressing D84E or D84C showed an MIC >10,000 and 78 µg/ml, respectively, implying that a negative charge is required at this position. These results were generally consistent with that of the L-alanine accumulation experiments in intact cells. We therefore concluded that charged amino acid residues (R45 and D84) in the AlaE transmembrane domain play a pivotal role in L-alanine export. Replacement of three cysteine residues at C22, C28 (both in TM-I), and C135 (C-terminal region) with alanine showed only a marginal effect on L-alanine export.

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.

New Enzymatic Method of Chiral Amino Acid Synthesis by Dynamic Kinetic Resolution of Amino Acid Amides: Use of Stereoselective Amino Acid Amidases in the Presence of α-Amino-ɛ-Caprolactam Racemase▿

PubMed Central

Yamaguchi, Shigenori; Komeda, Hidenobu; Asano, Yasuhisa

2007-01-01

d- and l-amino acids were produced from l- and d-amino acid amides by d-aminopeptidase from Ochrobactrum anthropi C1-38 and l-amino acid amidase from Pseudomonas azotoformans IAM 1603, respectively, in the presence of α-amino-ɛ-caprolactam racemase from Achromobacter obae as the catalyst by dynamic kinetic resolution of amino acid amides. PMID:17586677

The Effect of an Amino Acid Infusion on Central Thermoregulatory Control in Humans

PubMed Central

Nakajima, Yasufumi; Takamata, Akira; Matsukawa, Takashi; Sessler, Daniel I.; Kitamura, Yoshihiro; Ueno, Hiroshi; Tanaka, Yoshifumi; Mizobe, Toshiki

2005-01-01

Background Administration of protein or amino acids enhances thermogenesis, presumably by stimulating oxidative metabolism. However, hyperthermia results even when thermoregulatory responses are intact, suggesting that amino acids also alter central thermoregulatory control. We thus tested the hypothesis that amino acid infusion increases the thermoregulatory setpoint. Methods Nine male volunteers each participated on four study days in randomized order: 1) intravenous amino acids infused at 4 kJ·kg−1·hr−1 for 2.5 h combined with skin-surface warming; 2) amino acid infusion combined with cutaneous cooling; 3) a saline infusion combined with skin-surface warming; and, 4) saline infusion combined with cutaneous cooling. Results Amino acid infusion increased resting core temperature by 0.3 ± 0.1°C (mean ± SD) and oxygen consumption by 18 ± 12%. Furthermore, amino acid infusion increased the calculated core temperature threshold (triggering core temperature at a designated mean-skin temperature of 34°C) for active cutaneous vasodilation by 0.3 ± 0.3°C, for sweating by 0.2 ± 0.2°C, for thermoregulatory vasoconstriction by 0.3 ± 0.3°C, and for thermogenesis by 0.4 ± 0.5°C. Amino acid infusion did not alter the incremental response intensity (i.e., gain) of thermoregulatory defenses. Conclusions Amino acid infusion increased the metabolic rate and resting core temperature. However, amino acids also produced a synchronous increase in all major autonomic thermoregulatory defense thresholds; the increase in core temperature was identical to the setpoint increase — even in a cold environment with amble potential to dissipate heat. In subjects with intact thermoregulatory defenses, amino acid-induced hyperthermia appears to result from an elevated setpoint increase rather than increased metabolic rate per se. PMID:15108979

Amino acid residue Y196E substitution and C-terminal peptide synergistically alleviate the toxicity of Clostridium perfringens epsilon toxin.

PubMed

Yao, Wenwu; Kang, Lin; Gao, Shan; Zhuang, Xiangjin; Zhang, Tao; Yang, Hao; Ji, Bin; Xin, Wenwen; Wang, Jinglin

2015-06-15

Epsilon toxin (ETX) is produced by Clostridium perfringens type B and D strains, and is the causative agent of a lethal enterotoxemia in livestock animals and possibly in humans. However, many details of ETX structure and activity are not known. Therefore, it is important to clarify the relationship between ETX structure and activity. To explore the effect and mechanism of ETX amino acid residue Y196E substitution and C-terminal peptide on toxicity, four recombinant proteins, rETX (without 13 N-terminal peptides and 23 C-terminal peptides), rETX-C (rETX with 23 C-terminal peptides), rETX(Y196E) (rETX with an amino acid residue substitution at Y196) and rETX(Y196E)-C (rETX-C with a Y196E mutation), were constructed in this study. Both the amino acid residue Y196E substitution and the C-terminal peptide reduce ETX toxicity to a similar extent, and the two factors synergistically alleviate ETX toxicity. In addition, we demonstrated that the C-terminal peptides and Y196E amino acid mutation reduce the toxin toxicity in two different pathways: the C-terminal peptides inhibit the binding activity of toxins to target cells, and the Y196E amino acid mutation slightly inhibits the pore-forming or heptamer-forming process. Interaction between the two factors was not observed in pore-forming or binding assays but toxicity assays, which demonstrated that the relationship between domains of the toxin is more complicated than previously appreciated. However, the exact mechanism of synergistic action is not yet clarified. Copyright © 2015 Elsevier Ltd. All rights reserved.

The role of microbial amino acid metabolism in host metabolism.

PubMed

Neis, Evelien P J G; Dejong, Cornelis H C; Rensen, Sander S

2015-04-16

Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous proteins. In turn, gut bacteria also provide amino acids to the host. This could have significant implications in the context of insulin resistance and type 2 diabetes mellitus, conditions associated with elevated systemic concentrations of certain amino acids, in particular the aromatic and branched-chain amino acids. Moreover, several amino acids released by gut bacteria can serve as precursors for the synthesis of short-chain fatty acids, which also play a role in the development of obesity. In this review, we aim to compile the available evidence on the contribution of microbial amino acids to host amino acid homeostasis, and to assess the role of the gut microbiota as a determinant of amino acid and short-chain fatty acid perturbations in human obesity and type 2 diabetes mellitus.

A specific amino acid formula prevents alcoholic liver disease in rodents.

PubMed

Tedesco, Laura; Corsetti, Giovanni; Ruocco, Chiara; Ragni, Maurizio; Rossi, Fabio; Carruba, Michele O; Valerio, Alessandra; Nisoli, Enzo

2018-05-01

Chronic alcohol consumption promotes mitochondrial dysfunction, oxidative stress, defective protein metabolism, and fat accumulation in hepatocytes (liver steatosis). Inadequate amino acid metabolism is worsened by protein malnutrition, frequently present in alcohol-consuming patients, with reduced circulating branched-chain amino acids (BCAAs). Here we asked whether dietary supplementation with a specific amino acid mixture, enriched in BCAAs (BCAAem) and able to promote mitochondrial function in muscle of middle-aged rodents, would prevent mitochondrial dysfunction and liver steatosis in Wistar rats fed on a Lieber-DeCarli ethanol (EtOH)-containing liquid diet. Supplementation of BCAAem, unlike a mixture based on the amino acid profile of casein, abrogated the EtOH-induced fat accumulation, mitochondrial impairment, and oxidative stress in liver. These effects of BCAAem were accompanied by normalization of leucine, arginine, and tryptophan levels, which were reduced in liver of EtOH-consuming rats. Moreover, although the EtOH exposure of HepG2 cells reduced mitochondrial DNA, mitochondrial transcription factors, and respiratory chain proteins, the BCAAem but not casein-derived amino acid supplementation halted this mitochondrial toxicity. Nicotinamide adenine dinucleotide levels and sirtuin 1 (Sirt1) expression, as well as endothelial nitric oxide (eNOS) and mammalian/mechanistic target of rapamycin (mTOR) signaling pathways, were downregulated in the EtOH-exposed HepG2 cells. BCAAem reverted these molecular defects and the mitochondrial dysfunction, suggesting that the mitochondrial integrity obtained with the amino acid supplementation could be mediated through a Sirt1-eNOS-mTOR pathway. Thus a dietary activation of the mitochondrial biogenesis and function by a specific amino acid supplement protects against the EtOH toxicity and preserves the liver integrity in mammals. NEW & NOTEWORTHY Dietary supplementation of a specific amino acid formula prevents both

Amino acid ionic liquids.

PubMed

Ohno, Hiroyuki; Fukumoto, Kenta

2007-11-01

The preparation of ionic liquids derived from amino acids, and their properties, are outlined. Since amino acids have both a carboxylic acid residue and an amino group in a single molecule, they can be used as either anions or cations. These groups are also useful in their ability to introduce functional group(s). Twenty different natural amino acids were used as anions, to couple with the 1-ethyl-3-methylimidazolium cation. The salts obtained were all liquid at room temperature. The properties of the resulting ionic liquids (AAILs) depend on the side groups of the amino acids involved. These AAILs, composed of an amino acid with some functional groups such as a hydrogen bonding group, a charged group, or an aromatic ring, had an increased glass transition (or melting) temperature and/or higher viscosity as a result of additional interactions among the ions. Viscosity is reduced and the decomposition temperature of imidazolium-type salts is improved by using the tetrabutylphosphonium cation. The chirality of AAILs was maintained even upon heating to 150 degrees C after acetylation of the free amino group. The amino group was also modified to introduce a strong acid group so as to form hydrophobic and chiral ionic liquids. Unique phase behavior of the resulting hydrophobic ionic liquids and water mixture is found; the mixture is clearly phase separated at room temperature, but the solubility of water in this IL increases upon cooling, to give a homogeneous solution. This phase change is reversible, and separation occurs again by raising the temperature a few degrees. It is extraordinary for an IL/water mixture to display such behavior with a lower critical solution temperature. Some likely applications are proposed for these amino acid derived ionic liquids.

Formation of amino acids from NH3 /NO2, CO2 and H2O: implications for the prebiotic origin of biomolecules.

PubMed

Singh, Amrinder; Nisha; Singh, Palwinder

2015-11-15

The search for the conditions which must have prevailed in the long-distant past during the conversion of inanimate matter into animate matter is a fascinating area of research and it continues to draw the attention of the scientific community. The initiation of life on this planet must have been preceded by the development of biomolecules, amongst which amino acids have unique importance. Formation of amino acids under a certain set of conditions is shown in the present experiments. Solutions of ammonium carboxylates or the mixture of two such salts were prepared in 3:6.9:0.1 (v/v/v) acetonitrile/water/formic acid at a concentration of 50 μM. The studies were performed using a quadrupole time-of-flight (QqTOF) mass spectrometer. The formation of different amino acids was detected with high-resolution mass spectrometry. Here, we show the formation of amino acids when a solution of ammonium salts was injected into an electrospray ionization (ESI)-QqTOF-MS instrument. The ammonium salts were the source of NH3 and CO2 and H2 O was available in the medium. It seems that the combination of NH3 , CO2 , and H2 O leads to the formation of amino acids. Further to the literature reports of formation of amino acids under the reduced atmosphere represented by gases such as NH3 , CH4 , H2 and H2 O, here we demonstrate the formation of amino acids by the combination of NH3 /NO2 , CO2 and water vapours in the ESI source of the mass spectrometer. Copyright © 2015 John Wiley & Sons, Ltd.

Differential regulation of placental amino acid transport by saturated and unsaturated fatty acids.

PubMed

Lager, Susanne; Jansson, Thomas; Powell, Theresa L

2014-10-15

Fatty acids are critical for normal fetal development but may also influence placental function. We have previously reported that oleic acid (OA) stimulates amino acid transport in primary human trophoblasts (PHTs). In other tissues, saturated and unsaturated fatty acids have distinct effects on cellular signaling, for instance, palmitic acid (PA) but not OA reduces IκBα expression. We hypothesized that saturated and unsaturated fatty acids differentially affect trophoblast amino acid transport and cellular signaling. To test this hypothesis, PHTs were cultured in docosahexaenoic acid (DHA; 50 μM), OA (100 μM), or PA (100 μM). DHA and OA were also combined to test whether DHA could counteract the OA stimulatory effect on amino acid transport. The effects of fatty acids were compared against a vehicle control. Amino acid transport was measured by isotope-labeled tracers. Activation of inflammatory-related signaling pathways and the mechanistic target of rapamycin (mTOR) pathway were determined by Western blot analysis. Exposure of PHTs to DHA for 24 h reduced amino acid transport and phosphorylation of p38 MAPK, STAT3, mTOR, eukaryotic initiation factor 4E-binding protein 1, and ribosomal protein (rp)S6. In contrast, OA increased amino acid transport and phosphorylation of ERK, mTOR, S6 kinase 1, and rpS6. The combination of DHA with OA increased amino acid transport and rpS6 phosphorylation. PA did not affect amino acid transport but reduced IκBα expression. In conclusion, these fatty acids differentially regulated placental amino acid transport and cellular signaling. Taken together, these findings suggest that dietary fatty acids could alter the intrauterine environment by modifying placental function, thereby having long-lasting effects on the developing fetus. Copyright © 2014 the American Physiological Society.

Dynamics of amino acid utilization in Phaeobacter inhibens DSM 17395.

PubMed

Zech, Hajo; Hensler, Michael; Koßmehl, Sebastian; Drüppel, Katharina; Wöhlbrand, Lars; Trautwein, Kathleen; Colby, Thomas; Schmidt, Jürgen; Reinhardt, Richard; Schmidt-Hohagen, Kerstin; Schomburg, Dietmar; Rabus, Ralf

2013-10-01

Time-resolved utilization of multiple amino acids by Phaeobacter inhibens DSM 17395 was studied during growth with casamino acids. The 15 detected amino acids could be grouped according to depletion rate into four different categories, i.e. from rapid (category I) to nondepletion (category IV). Upon entry into stationary growth phase, amino acids of category I (e.g. glutamate) were (almost) completely depleted, while those of categories II (e.g. leucine) and III (e.g. serine) were further consumed at varying rates and to different extents. Thus, cultures entered stationary growth phase despite the ample presence of organic nutrients, i.e. under nonlimiting conditions. Integrated proteomic and metabolomic analysis identified 1747 proteins and 94 intracellular metabolites. Of these, 180 proteins and 86 metabolites displayed altered abundance levels during growth. Most strikingly, abundance and activity profiles of alanine dehydrogenase concomitantly increased with the onset of enhanced alanine utilization during transition into stationary growth phase. Most enzymes of amino acid and central metabolism, however, displayed unaltered abundances across exponential and stationary growth phases. In contrast, metabolites of the Entner-Doudoroff pathway and gluconeogenesis as well as cellular fatty acids increased markedly in abundance in early stationary growth phase. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Amino Acids from a Comet

NASA Technical Reports Server (NTRS)

Cook, Jamie Elisla

2009-01-01

NASA's Stardust spacecraft returned samples from comet 81P/Wild 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary- vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a coetary amino acid.

Comparison of amino acid digestibility of feedstuffs determined with the precision-fed cecectomized rooster assay and the standardized ileal amino acid digestibility assay.

PubMed

Kim, E J; Utterback, P L; Applegate, T J; Parsons, C M

2011-11-01

The objective of this study was to evaluate and compare amino acid digestibility of several feedstuffs using 2 commonly accepted methods: the precision-fed cecectomized rooster assay (PFR) and the standardized ileal amino acid assay (SIAAD). Six corn, 6 corn distillers dried grains with or without solubles (DDGS/DDG), one wet distillers grains, one condensed solubles, 2 meat and bone meal (MBM) and a poultry byproduct meal were evaluated. Due to insufficient amounts, the wet distillers grains and condensed solubles were only evaluated in roosters. Standardized amino acid digestibility varied among the feed ingredients and among samples of the same ingredient for both methods. For corn, there were generally no differences in amino acid digestibility between the 2 methods. When differences did occur, there was no consistent pattern among the individual amino acids and methods. Standardized amino acid digestibility was not different between the 2 methods for 4 of the DDG samples; however, the PFR yielded higher digestibility values for a high protein DDG and a conventionally processed DDGS. The PFR yielded higher amino acid digestibility values than the SIAAD for several amino acids in 1 MBM and the poultry byproduct meal, but it yielded lower digestibility values for the other MBM. Overall, there were no consistent differences between methods for amino acid digestibility values. In conclusion, the PFR and SIAAD methods are acceptable for determining amino acid digestibility. However, these procedures do not always yield similar results for all feedstuffs evaluated. Thus, further studies are needed to understand the underlying causes in this variability.

Distribution of Amino Acids in Lunar Regolith

NASA Technical Reports Server (NTRS)

Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Noble, S. K.; Gibson, E. K., Jr.

2014-01-01

One of the most eagerly studied questions upon initial return of lunar samples was whether significant amounts of organic compounds, including amino acids, were present. Analyses during the 1970s produced only tentative and inconclusive identifications of indigenous amino acids. Those analyses were hampered by analytical difficulties including relative insensitivity to certain compounds, the inability to separate chiral enantiomers, and the lack of compound-specific isotopic measurements, which made it impossible to determine whether the detected amino acids were indigenous to the lunar samples or the results of contamination. Numerous advances have been made in instrumentation and methodology for amino acid characterization in extraterrestrial samples in the intervening years, yet the origin of amino acids in lunar regolith samples has been revisited only once for a single lunar sample, (3) and remains unclear. Here, we present initial data from the analyses of amino acid abundances in 12 lunar regolith samples. We discuss these abundances in the context of four potential amino acid sources: (1) terrestrial biological contamination; (2) contamination from lunar module (LM) exhaust; (3) derivation from solar windimplanted precursors; and (4) exogenous delivery from meteorites.

Secretion of alpha 2-plasmin inhibitor is impaired by amino acid deletion in a small region of the molecule.

PubMed

Toyota, S; Hirosawa, S; Aoki, N

1994-02-01

Alpha 2-plasmin inhibitor (alpha 2PI) deficiency Okinawa results from defective secretion of the inhibitor from the liver and appears to be a direct consequence of the deletion of Glu137 in the amino acid sequence of alpha 2PI. To examine the effects of replacing the amino acid occupying position 137 or deleting its neighboring amino acid on alpha 2PI secretion, we used oligonucleotide-directed mutagenesis of alpha 2PI cDNA to change the codon specifying Glu137 or delete a codon specifying its neighboring amino acid. The effects were determined by pulse-chase experiments and by enzyme-linked immunosorbent assay of media from transiently transfected COS-7 cells. Replacement of Glu137 with an amino acid other than Cys had little effect on alpha 2PI secretion. In contrast, deletion of an amino acid in a region spanning a sequence of less than 30 amino acids including positions 127 and 137 severely impaired the secretion. The results suggest that structural integrity of the region, rather than its component amino acids, is important for the intracellular transport and secretion of alpha 2PI.

Plasma free amino acid kinetics in rainbow trout (Oncorhynchus mykiss) using a bolus injection of 15N-labeled amino acids.

PubMed

Robinson, Jacob William; Yanke, Dan; Mirza, Jeff; Ballantyne, James Stuart

2011-02-01

To gain insight into the metabolic design of the amino acid carrier systems in fish, we injected a bolus of (15)N amino acids into the dorsal aorta in mature rainbow trout (Oncorhynchus mykiss). The plasma kinetic parameters including concentration, pool size, rate of disappearance (R(d)), half-life and turnover rate were determined for 15 amino acids. When corrected for metabolic rate, the R(d) values obtained for trout for most amino acids were largely comparable to human values, with the exception of glutamine (which was lower) and threonine (which was higher). R(d) values ranged from 0.9 μmol 100 g(-1) h(-1) (lysine) to 22.1 μmol 100 g(-1) h(-1) (threonine) with most values falling between 2 and 6 μmol 100 g(-1) h(-1). There was a significant correlation between R(d) and the molar proportion of amino acids in rainbow trout whole body protein hydrolysate. Other kinetic parameters did not correlate significantly with whole body amino acid composition. This indicates that an important design feature of the plasma-free amino acids system involves proportional delivery of amino acids to tissues for protein synthesis.

Plasma amino acid and metabolite signatures tracking diabetes progression in the UCD-T2DM rat model.

PubMed

Piccolo, Brian D; Graham, James L; Stanhope, Kimber L; Fiehn, Oliver; Havel, Peter J; Adams, Sean H

2016-06-01

Elevations of plasma concentrations of branched-chain amino acids (BCAAs) are observed in human insulin resistance and type 2 diabetes mellitus (T2DM); however, there has been some controversy with respect to the passive or causative nature of the BCAA phenotype. Using untargeted metabolomics, plasma BCAA and other metabolites were assessed in lean control Sprague-Dawley rats (LC) and temporally during diabetes development in the UCD-T2DM rat model, i.e., prediabetic (PD) and 2 wk (D2W), 3 mo (D3M), and 6 mo (D6M) post-onset of diabetes. Plasma leucine, isoleucine, and valine concentrations were elevated only in D6M rats compared with D2W rats (by 28, 29, and 30%, respectively). This was in contrast to decreased plasma concentrations of several other amino acids in D3M and/or D6M relative to LC rats (Ala, Arg, Glu, Gln, Met, Ser, Thr, and Trp). BCAAs were positively correlated with fasting glucose and negatively correlated with plasma insulin, total body weight, total adipose tissue weight, and gastrocnemius muscle weight in the D3M and D6M groups. Multivariate analysis revealed that D3M and D6M UCD-T2DM rats had lower concentrations of amino acids, amino acid derivatives, 1,5-anhydroglucitol, and conduritol-β-opoxide and higher concentrations of uronic acids, pantothenic acids, aconitate, benzoic acid, lactate, and monopalmitin-2-glyceride relative to PD and D2W UCD-T2DM rats. The UCD-T2DM rat does not display elevated plasma BCAA concentrations until 6 mo post-onset of diabetes. With the acknowledgement that this is a rodent model of T2DM, the results indicate that elevated plasma BCAA concentrations are not necessary or sufficient to elicit an insulin resistance or T2DM onset. Copyright © 2016 the American Physiological Society.

Metabolomic Profiling of Fatty Acid and Amino Acid Metabolism in Youth With Obesity and Type 2 Diabetes

PubMed Central

Mihalik, Stephanie J.; Michaliszyn, Sara F.; de las Heras, Javier; Bacha, Fida; Lee, SoJung; Chace, Donald H.; DeJesus, Victor R.; Vockley, Jerry; Arslanian, Silva A.

2012-01-01

OBJECTIVE We compared acylcarnitine (AcylCN) species, common amino acid and fat oxidation (FOX) byproducts, and plasma amino acids in normal weight (NW; n = 39), obese (OB; n = 64), and type 2 diabetic (n = 17) adolescents. RESEARCH DESIGN AND METHODS Fasting plasma was analyzed by tandem mass spectrometry, body composition by dual energy X-ray absorptiometry and computed tomography, and total-body lipolysis and substrate oxidation by [2H5]glycerol and indirect calorimetry, respectively. In vivo insulin sensitivity (IS) was assessed with a 3-h hyperinsulinemic-euglycemic clamp. RESULTS Long-chain AcylCNs (C18:2-CN to C14:0-CN) were similar among the three groups. Medium- to short-chain AcylCNs (except C8 and C10) were significantly lower in type 2 diabetes compared with NW, and when compared with OB, C2-, C6-, and C10-CN were lower. Amino acid concentrations were lower in type 2 diabetes compared with NW. Fasting lipolysis and FOX were higher in OB and type 2 diabetes compared with NW, and the negative association of FOX to C10:1 disappeared after controlling for adiposity, Tanner stage, and sex. IS was lower in OB and type 2 diabetes with positive associations between IS and arginine, histidine, and serine after adjusting for adiposity, Tanner stage, and sex. CONCLUSIONS These metabolomics results, together with the increased rates of in vivo FOX, are not supportive of defective fatty acid or amino acid metabolism in obesity and type 2 diabetes in youth. Such observations are consistent with early adaptive metabolic plasticity in youth, which over time—with continued obesity and aging—may become dysfunctional, as observed in adults. PMID:22266733

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...

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...

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.

Amino acid "little Big Bang": representing amino acid substitution matrices as dot products of Euclidian vectors.

PubMed

Zimmermann, Karel; Gibrat, Jean-François

2010-01-04

Sequence comparisons make use of a one-letter representation for amino acids, the necessary quantitative information being supplied by the substitution matrices. This paper deals with the problem of finding a representation that provides a comprehensive description of amino acid intrinsic properties consistent with the substitution matrices. We present a Euclidian vector representation of the amino acids, obtained by the singular value decomposition of the substitution matrices. The substitution matrix entries correspond to the dot product of amino acid vectors. We apply this vector encoding to the study of the relative importance of various amino acid physicochemical properties upon the substitution matrices. We also characterize and compare the PAM and BLOSUM series substitution matrices. This vector encoding introduces a Euclidian metric in the amino acid space, consistent with substitution matrices. Such a numerical description of the amino acid is useful when intrinsic properties of amino acids are necessary, for instance, building sequence profiles or finding consensus sequences, using machine learning algorithms such as Support Vector Machine and Neural Networks algorithms.

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase

PubMed Central

Gonzalez, Jeannette; Ramirez, Jennifer

2018-01-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer’s and Huntington’s disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer’s disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (KI value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower KI value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding. PMID:27522651

Evaluating Fmoc-amino acids as selective inhibitors of butyrylcholinesterase.

PubMed

Gonzalez, Jeannette; Ramirez, Jennifer; Schwans, Jason P

2016-12-01

Cholinesterases are involved in neuronal signal transduction, and perturbation of function has been implicated in diseases, such as Alzheimer's and Huntington's disease. For the two major classes of cholinesterases, such as acetylcholinesterase (AChE) and butyrylcholinesterase (BChE), previous studies reported BChE activity is elevated in patients with Alzheimer's disease, while AChE levels remain the same or decrease. Thus, the development of potent and specific inhibitors of BChE have received much attention as a potential therapeutic in the alleviation of neurodegenerative diseases. In this study, we evaluated amino acid analogs as selective inhibitors of BChE. Amino acid analogs bearing a 9-fluorenylmethyloxycarbonyl (Fmoc) group were tested, as the Fmoc group has structural resemblance to previously described inhibitors. We identified leucine, lysine, and tryptophan analogs bearing the Fmoc group as selective inhibitors of BChE. The Fmoc group contributed to inhibition, as analogs bearing a carboxybenzyl group showed ~tenfold higher values for the inhibition constant (K I value). Inclusion of a t-butoxycarbonyl on the side chain of Fmoc tryptophan led to an eightfold lower K I value compared to Fmoc tryptophan alone suggesting that modifications of the amino acid side chains may be designed to create inhibitors with higher affinity. Our results identify Fmoc-amino acids as a scaffold upon which to design BChE-specific inhibitors and provide the foundation for further experimental and computational studies to dissect the interactions that contribute to inhibitor binding.

Catalytic enantioselective silylation of N-sulfonylimines: asymmetric synthesis of α-amino acids from CO2 via stereospecific carboxylation of α-amino silanes.

PubMed

Mita, Tsuyoshi; Sugawara, Masumi; Saito, Keisuke; Sato, Yoshihiro

2014-06-06

A catalytic enantioselective silylation of N-tert-butylsulfonylimines using a Cu-secondary diamine complex was demonstrated. The resulting optically active α-amino silanes could be carboxylated under a CO2 atmosphere (1 atm) to afford the corresponding α-amino acids in a stereoretentive manner. This two-step sequence provides a new synthetic protocol for optically active α-amino acids from gaseous CO2 and imines in the presence of a catalytic amount of a chiral source.

Abc Amino Acids: Design, Synthesis, and Properties of New Photoelastic Amino Acids

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

Standaert, Robert F; Park, Dr Seung Bum

2006-01-01

Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A inmore » the backbone upon transa?cis photoisomerization. This isomer, designated mpAbc, has substituents at meta and para positions on the inner (azo-linked) and outer rings, respectively. An efficient synthesis of Fmoc-protected mpAbc was executed in which the biaryl components were formed via Suzuki couplings and the azo linkage was formed via amine/nitroso condensation; protected forms of three other Abc isomers were prepared similarly. A decapeptide incorporating mpAbc was synthesized by conventional solid-phase methods and displayed characteristic azobenzene photochemical behavior with optimal conversion to the cis isomer at 360 nm and a thermal cisa?trans half life of 100 min. at 80 AoC.« less

Amino Acids and Chirality

NASA Technical Reports Server (NTRS)

Cook, Jamie E.

2012-01-01

Amino acids are among the most heavily studied organic compound class in carbonaceous chondrites. The abundance, distributions, enantiomeric compositions, and stable isotopic ratios of amino acids have been determined in carbonaceous chondrites fi'om a range of classes and petrographic types, with interesting correlations observed between these properties and the class and typc of the chondritcs. In particular, isomeric distributions appear to correlate with parent bodies (chondrite class). In addition, certain chiral amino acids are found in enantiomeric excess in some chondrites. The delivery of these enantiomeric excesses to the early Earth may have contributed to the origin of the homochirality that is central to life on Earth today. This talk will explore the amino acids in carbonaceous chondritcs and their relevance to the origin of life.

Detection of non-protein amino acids in the presence of protein amino acids. II.

NASA Technical Reports Server (NTRS)

Shapshak, P.; Okaji, M.

1972-01-01

Studies conducted with the JEOL 5AH amino acid analyzer are described. This instrument makes possible the programming of the chromatographic process. Data are presented showing the separations of seventeen non-protein amino acids in the presence of eighteen protein amino acids. It is pointed out that distinct separations could be obtained in the case of a number of chemically similar compounds, such as ornithine and lysine, N-amidino alanine and arginine, and iminodiacetic acid and S-carboxymethyl cysteine and aspartic acid.

40 CFR 721.9795 - Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl) amino...

Code of Federal Regulations, 2011 CFR

2011-07-01

... benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl)amino]-, disodium salt... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenesulfonic acid, 2,2â²-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl) amino]-, disodium salt, substituted with dialkyl amines...

40 CFR 721.9795 - Benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl) amino...

Code of Federal Regulations, 2010 CFR

2010-07-01

... benzenesulfonic acid, 2,2′-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl)amino]-, disodium salt... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenesulfonic acid, 2,2â²-(1,2-ethenediyl)bis[(4,6-dichloro-1,3,5-triazin-2-yl) amino]-, disodium salt, substituted with dialkyl amines...

Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis.

PubMed

Shin, Byung-Sik; Katoh, Takayuki; Gutierrez, Erik; Kim, Joo-Ran; Suga, Hiroaki; Dever, Thomas E

2017-08-21

Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline. Published by Oxford University Press on behalf of Nucleic Acids Research 2017.

Characteristics and formation of amino acids and hydroxy acids of the Murchison meteorite

NASA Technical Reports Server (NTRS)

Cronin, J. R.; Cooper, G. W.; Pizzarello, S.

1995-01-01

Eight characteristics of the unique suite of amino acids and hydroxy acids found in the Murchison meteorite can be recognized on the basis of detailed molecular and isotopic analyses. The marked structural correspondence between the alpha-amino acids and alpha-hydroxy acids and the high deuterium/hydrogen ratio argue persuasively for their formation by aqueous phase Strecker reactions in the meteorite parent body from presolar, i.e., interstellar, aldehydes, ketones, ammonia, and hydrogen cyanide. The characteristics of the meteoritic suite of amino acids and hydroxy acids are briefly enumerated and discussed with regard to their consonance with this interstellar-parent body formation hypothesis. The hypothesis has interesting implications for the organic composition of both the primitive parent body and the presolar nebula.

Amino acid homeostasis and signalling in mammalian cells and organisms

PubMed Central

Bröer, Angelika

2017-01-01

Cells have a constant turnover of proteins that recycle most amino acids over time. Net loss is mainly due to amino acid oxidation. Homeostasis is achieved through exchange of essential amino acids with non-essential amino acids and the transfer of amino groups from oxidised amino acids to amino acid biosynthesis. This homeostatic condition is maintained through an active mTORC1 complex. Under amino acid depletion, mTORC1 is inactivated. This increases the breakdown of cellular proteins through autophagy and reduces protein biosynthesis. The general control non-derepressable 2/ATF4 pathway may be activated in addition, resulting in transcription of genes involved in amino acid transport and biosynthesis of non-essential amino acids. Metabolism is autoregulated to minimise oxidation of amino acids. Systemic amino acid levels are also tightly regulated. Food intake briefly increases plasma amino acid levels, which stimulates insulin release and mTOR-dependent protein synthesis in muscle. Excess amino acids are oxidised, resulting in increased urea production. Short-term fasting does not result in depletion of plasma amino acids due to reduced protein synthesis and the onset of autophagy. Owing to the fact that half of all amino acids are essential, reduction in protein synthesis and amino acid oxidation are the only two measures to reduce amino acid demand. Long-term malnutrition causes depletion of plasma amino acids. The CNS appears to generate a protein-specific response upon amino acid depletion, resulting in avoidance of an inadequate diet. High protein levels, in contrast, contribute together with other nutrients to a reduction in food intake. PMID:28546457

Amino acid substrates impose polyamine, eIF5A, or hypusine requirement for peptide synthesis

PubMed Central

Shin, Byung-Sik; Katoh, Takayuki; Gutierrez, Erik; Kim, Joo-Ran; Suga, Hiroaki

2017-01-01

Abstract Whereas ribosomes efficiently catalyze peptide bond synthesis by most amino acids, the imino acid proline is a poor substrate for protein synthesis. Previous studies have shown that the translation factor eIF5A and its bacterial ortholog EF-P bind in the E site of the ribosome where they contact the peptidyl-tRNA in the P site and play a critical role in promoting the synthesis of polyproline peptides. Using misacylated Pro-tRNAPhe and Phe-tRNAPro, we show that the imino acid proline and not tRNAPro imposes the primary eIF5A requirement for polyproline synthesis. Though most proline analogs require eIF5A for efficient peptide synthesis, azetidine-2-caboxylic acid, a more flexible four-membered ring derivative of proline, shows relaxed eIF5A dependency, indicating that the structural rigidity of proline might contribute to the requirement for eIF5A. Finally, we examine the interplay between eIF5A and polyamines in promoting translation elongation. We show that eIF5A can obviate the polyamine requirement for general translation elongation, and that this activity is independent of the conserved hypusine modification on eIF5A. Thus, we propose that the body of eIF5A functionally substitutes for polyamines to promote general protein synthesis and that the hypusine modification on eIF5A is critically important for poor substrates like proline. PMID:28637321

Vba2p, a vacuolar membrane protein involved in basic amino acid transport in Schizosaccharomyces pombe.

PubMed

Sugimoto, Naoko; Iwaki, Tomoko; Chardwiriyapreecha, Soracom; Shimazu, Masamitsu; Sekito, Takayuki; Takegawa, Kaoru; Kakinuma, Yoshimi

2010-01-01

A recent study filling the gap in the genome sequence in the left arm of chromosome 2 of Schizosaccharomyces pombe revealed a homolog of budding yeast Vba2p, a vacuolar transporter of basic amino acids. GFP-tagged Vba2p in fission yeast was localized to the vacuolar membrane. Upon disruption of vba2, the uptake of several amino acids, including lysine, histidine, and arginine, was impaired. A transient increase in lysine uptake under nitrogen starvation was lowered by this mutation. These findings suggest that Vba2p is involved in basic amino acid transport in S. pombe under diverse conditions.

Dissolved Divalent Metal and pH Effects on Amino Acid Polymerization: A Thermodynamic Evaluation.

PubMed

Kitadai, Norio

2017-03-01

Polymerization of amino acids is a fundamentally important step for the chemical evolution of life. Nevertheless, its response to changing environmental conditions has not yet been well understood because of the lack of reliable quantitative information. For thermodynamics, detailed prediction over diverse combinations of temperature and pH has been made only for a few amino acid-peptide systems. This study used recently reported thermodynamic dataset for the polymerization of the simplest amino acid "glycine (Gly)" to its short peptides (di-glycine and tri-glycine) to examine chemical and structural characteristics of amino acids and peptides that control the temperature and pH dependence of polymerization. Results showed that the dependency is strongly controlled by the intramolecular distance between the amino and carboxyl groups in an amino acid structure, although the side-chain group role is minor. The polymerization behavior of Gly reported earlier in the literature is therefore expected to be a typical feature for those of α-amino acids. Equilibrium calculations were conducted to examine effects of dissolved metals as a function of pH on the monomer-polymer equilibria of Gly. Results showed that metals shift the equilibria toward the monomer side, particularly at neutral and alkaline pH. Metals that form weak interaction with Gly (e.g., Mg 2+ ) have no noticeable influence on the polymerization, although strong interaction engenders significant decrease of the equilibrium concentrations of Gly peptides. Considering chemical and structural characteristics of Gly and Gly peptides that control their interactions with metals, it can be expected that similar responses to the addition of metals are applicable in the polymerization of neutral α-amino acids. Neutral and alkaline aqueous environments with dissolved metals having high affinity with neutral α-amino acids (e.g., Cu 2+ ) are therefore not beneficial places for peptide bond formation on the primitive

The Path of Carbon in Photosynthesis II. Amino Acids

DOE R&D Accomplishments Database

Stepka, W.; Benson, A. A.; Calvin, M.

1948-05-25

The radioactive amino acid's synthesized from C{sup 14}O{sub 2} by green algae both in the light and in the dark after CO{sub 2}-free preillumination have been separated and identified using paper chromatography and radioautography. The radioactive amino acids identified were aspartic acid, alanine and smaller amounts of 3- and 4-carbon amino acids. This finding as well as the total absence of radioactive glutamic acid substantiates the mechanism for reduction of CO{sub 2} previously postulated by members of this laboratory.

Identification and functional characterization of a Na+-independent neutral amino acid transporter with broad substrate selectivity.

PubMed

Segawa, H; Fukasawa, Y; Miyamoto, K; Takeda, E; Endou, H; Kanai, Y

1999-07-09

We have isolated a cDNA from rat small intestine that encodes a novel Na+-independent neutral amino acid transporter with distinctive characteristics in substrate selectivity and transport property. The encoded protein, designated L-type amino acid transporter-2 (LAT-2), shows amino acid sequence similarity to the system L Na+-independent neutral amino acid transporter LAT-1 (Kanai, Y., Segawa, H., Miyamoto, K., Uchino, H., Takeda, E., and Endou, H. (1998) J. Biol. Chem. 273, 23629-23632) (50% identity) and the system y+L transporters y+LAT-1 (47%) and KIAA0245/y+LAT-2 (45%) (Torrents, D., Estevez, R., Pineda, M., Fernandez, E., Lloberas, J., Shi, Y.-B., Zorzano, A., and Palacin, M. (1998) J. Biol. Chem. 273, 32437-32445). LAT-2 is a nonglycosylated membrane protein. It requires 4F2 heavy chain, a type II membrane glycoprotein, for its functional expression in Xenopus oocytes. LAT-2-mediated transport is not dependent on Na+ or Cl- and is inhibited by a system L-specific inhibitor, 2-aminobicyclo-(2,2,1)-heptane-2-carboxylic acid (BCH), indicating that LAT-2 is a second isoform of the system L transporter. Compared with LAT-1, which prefers large neutral amino acids with branched or aromatic side chains, LAT-2 exhibits remarkably broad substrate selectivity. It transports all of the L-isomers of neutral alpha-amino acids. LAT-2 exhibits higher affinity (Km = 30-50 microM) to Tyr, Phe, Trp, Thr, Asn, Ile, Cys, Ser, Leu, Val, and Gln and relatively lower affinity (Km = 180-300 microM) to His, Ala, Met, and Gly. In addition, LAT-2 mediates facilitated diffusion of substrate amino acids, as distinct from LAT-1, which mediates amino acid exchange. LAT-2-mediated transport is increased by lowering the pH level, with peak activity at pH 6.25, because of the decrease in the Km value without changing the Vmax value. Because of these functional properties and a high level of expression of LAT-2 in the small intestine, kidney, placenta, and brain, it is suggested that the

Amino Acid Control over Deoxyribonucleic Acid Synthesis in Escherichia coli Infected With T-Even Bacteriophage

PubMed Central

Donini, Pierluigi

1970-01-01

Starvation for a required amino acid of normal or RCstrEscherichia coli infected with T-even phages arrests further synthesis of phage deoxyribonucleic acid (DNA). This amino acid control over phage DNA synthesis does not occur in RCrelE. coli mutants. Heat inactivation of a temperature-sensitive aminoacyl-transfer ribonucleic acid (RNA) synthetase similarly causes an arrest of phage DNA synthesis in infected cells of RCstr phenotype but not in cells of RCrel phenotype. Inhibition of phage DNA synthesis in amino acid-starved RCstr host cells can be reversed by addition of chloramphenicol to the culture. Thus, the general features of amino acid control over T-even phage DNA synthesis are entirely analogous to those known for amino acid control over net RNA synthesis of uninfected bacteria. This analogy shows that the bacterial rel locus controls a wider range of macromolecular syntheses than had been previously thought. PMID:4914067

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

Scaleable catalytic asymmetric Strecker syntheses of unnatural α-amino acids

PubMed Central

Zuend, Stephan J.; Coughlin, Matthew P.; Lalonde, Mathieu P.; Jacobsen, Eric N.

2009-01-01

α-Amino acids are essential building blocks for protein synthesis, and are also widely useful as components of medicinally active molecules and chiral catalysts.1,2,3,4,5 Efficient chemo-enzymatic methods for the synthesis of enantioenriched α-amino acids have been devised, but the scope of these methods for the synthesis of unnatural amino acids is limited.6,7 Alkene hydrogenation is broadly useful for enantioselective catalytic synthesis of many classes of amino acids,8,9 but this approach is not applicable to the synthesis of α-amino acids bearing aryl or quaternary alkyl α-substituents. The Strecker synthesis—the reaction of an imine or imine equivalent with hydrogen cyanide, followed by nitrile hydrolysis—is an especially versatile chemical method for the synthesis of racemic α-amino acids (Fig. 1).10,11 Asymmetric Strecker syntheses using stoichiometric chiral reagents have been applied successfully on gram-to-multi-kilogram scales to the preparation of enantiomerically enriched α-amino acids.12,13,14 In principle, Strecker syntheses employing sub-stoichiometric quantities of a chiral reagent provide a practical alternative to these approaches, but the reported catalytic asymmetric methods have seen only limited use on preparative scales (e.g., > 1 gram).15,16 The limited use of existing catalytic methodologies may be ascribed to several important practical drawbacks, including the relatively complex and precious nature of the catalysts, and the requisite use of hazardous cyanide sources. Herein we report a new catalytic asymmetric method for the syntheses of highly enantiomerically enriched non-proteinogenic amino acids using a simple chiral amido-thiourea catalyst to control the key hydrocyanation step. Because this catalyst is robust and lacks sensitive functional groups, it is compatible with safely handled aqueous cyanide salts, and is thus adaptable to large-scale synthesis. This new methodology can be applied to the efficient syntheses of

Pairwise amino acid secondary structural propensities

NASA Astrophysics Data System (ADS)

Chemmama, Ilan E.; Chapagain, Prem P.; Gerstman, Bernard S.

2015-04-01

We investigate the propensities for amino acids to form a specific secondary structure when they are paired with other amino acids. Our investigations use molecular dynamics (MD) computer simulations, and we compare the results to those from the Protein Data Bank (PDB). Proper comparison requires weighting of the MD results in a manner consistent with the relative frequency of appearance in the PDB of each possible pair of amino acids. We find that the propensity for an amino acid to assume a secondary structure varies dramatically depending on the amino acid that is before or after it in the primary sequence. This cooperative effect means that when selecting amino acids to facilitate the formation of a secondary structure in peptide engineering experiments, the adjacent amino acids must be considered. We also examine the preference for a secondary structure in bacterial proteins and compare the results to those of human proteins.

An SFG study of interfacial amino acids at the hydrophilic SiO2 and hydrophobic deuterated polystyrene surfaces.

PubMed

Holinga, George J; York, Roger L; Onorato, Robert M; Thompson, Christopher M; Webb, Nic E; Yoon, Alfred P; Somorjai, Gabor A

2011-04-27

Sum frequency generation (SFG) vibrational spectroscopy was employed to characterize the interfacial structure of eight individual amino acids--L-phenylalanine, L-leucine, glycine, L-lysine, L-arginine, L-cysteine, L-alanine, and L-proline--in aqueous solution adsorbed at model hydrophilic and hydrophobic surfaces. Specifically, SFG vibrational spectra were obtained for the amino acids at the solid-liquid interface between both hydrophobic d(8)-polystyrene (d(8)-PS) and SiO(2) model surfaces and phosphate buffered saline (PBS) at pH 7.4. At the hydrophobic d(8)-PS surface, seven of the amino acids solutions investigated showed clear and identifiable C-H vibrational modes, with the exception being l-alanine. In the SFG spectra obtained at the hydrophilic SiO(2) surface, no C-H vibrational modes were observed from any of the amino acids studied. However, it was confirmed by quartz crystal microbalance that amino acids do adsorb to the SiO(2) interface, and the amino acid solutions were found to have a detectable and widely varying influence on the magnitude of SFG signal from water at the SiO(2)/PBS interface. This study provides the first known SFG spectra of several individual amino acids in aqueous solution at the solid-liquid interface and under physiological conditions.

Amino Acid Degradation after Meteoritic Impact Simulation

NASA Technical Reports Server (NTRS)

Bertrand, M.; Westall, F.; vanderGaast, S.; Vilas, F.; Hoerz, F.; Barnes, G.; Chabin, A.; Brack, A.

2008-01-01

Amino acids are among the most important prebiotic molecules as it is from these precursors that the building blocks of life were formed [1]. Although organic molecules were among the components of the planetesimals making up the terrestrial planets, large amounts of primitive organic precursor molecules are believed to be exogenous in origin and to have been imported to the Earth via micrometeorites, carbonaceous meteorites and comets, especially during the early stages of the formation of the Solar System [1,2]. Our study concerns the hypothesis that prebiotic organic matter, present on Earth, was synthesized in the interstellar environment, and then imported to Earth by meteorites or micrometeorites. We are particularly concerned with the formation and fate of amino acids. We have already shown that amino acid synthesis is possible inside cometary grains under interstellar environment conditions [3]. We are now interested in the effects of space conditions and meteoritic impact on these amino acids [4-6]. Most of the extraterrestrial organic molecules known today have been identified in carbonaceous chondrite meteorites [7]. One of the components of these meteorites is a clay with a composition close to that of saponite, used in our experiments. Two American teams have studied the effects of impact on various amino acids [8,9]. [8] investigated amino acids in saturated solution in water with pressure ranges between 5.1 and 21 GPa and temperature ranges between 412 and 870 K. [9] studied amino acids in solid form associated with and without minerals (Murchison and Allende meteorite extracts) and pressure ranges between 3 and 30 GPa. In these two experiments, the amino acids survived up to 15 GPa. At higher pressure, the quantity of preserved amino acids decreases quickly. Some secondary products such as dipeptides and diketopiperazins were identified in the [8] experiment.

D-Amino Acids in Living Higher Organisms

NASA Astrophysics Data System (ADS)

Fujii, Noriko

2002-04-01

The homochirality of biological amino acids (L-amino acids) and of the RNA/DNA backbone (D-ribose) might have become established before the origin of life. It has been considered that D-amino acids and L-sugars were eliminated on the primitive Earth. Therefore, the presence and function of D-amino acids in living organisms have not been studied except for D-amino acids in the cell walls of microorganisms. However, D-amino acids were recently found in various living higher organisms in the form of free amino acids, peptides, and proteins. Free D-aspartate and D-serine are present and may have important physiological functions in mammals. D-amino acids in peptides are well known as opioid peptides and neuropeptides. In protein, D-aspartate residues increase during aging. This review deals with recent advances in the study of D-amino acids in higher organisms.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, M.M.; Shoup, T.

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is [{sup 18}F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an {alpha}-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of {alpha}-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-09-15

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

Amino acid analogs for tumor imaging

DOEpatents

Goodman, Mark M.; Shoup, Timothy

1998-10-06

The invention provides novel amino acid compounds of use in detecting and evaluating brain and body tumors. These compounds combine the advantageous properties of 1-amino-cycloalkyl-1-carboxylic acids, namely, their rapid uptake and prolonged retention in tumors with the properties of halogen substituents, including certain useful halogen isotopes including fluorine-18, iodine-123, iodine-125, iodine-131, bromine-75, bromine-76, bromine-77 and bromine-82. In one aspect, the invention features amino acid compounds that have a high specificity for target sites when administered to a subject in vivo. Preferred amino acid compounds show a target to non-target ratio of at least 5:1, are stable in vivo and substantially localized to target within 1 hour after administration. An especially preferred amino acid compound is ›.sup.18 F!-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an .alpha.-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of .alpha.-aminoisobutyric acid.

Protein phosphatase 2Cm is a critical regulator of branched-chain amino acid catabolism in mice and cultured cells.

PubMed

Lu, Gang; Sun, Haipeng; She, Pengxiang; Youn, Ji-Youn; Warburton, Sarah; Ping, Peipei; Vondriska, Thomas M; Cai, Hua; Lynch, Christopher J; Wang, Yibin

2009-06-01

The branched-chain amino acids (BCAA) are essential amino acids required for protein homeostasis, energy balance, and nutrient signaling. In individuals with deficiencies in BCAA, these amino acids can be preserved through inhibition of the branched-chain-alpha-ketoacid dehydrogenase (BCKD) complex, the rate-limiting step in their metabolism. BCKD is inhibited by phosphorylation of its E1alpha subunit at Ser293, which is catalyzed by BCKD kinase. During BCAA excess, phosphorylated Ser293 (pSer293) becomes dephosphorylated through the concerted inhibition of BCKD kinase and the activity of an unknown intramitochondrial phosphatase. Using unbiased, proteomic approaches, we have found that a mitochondrial-targeted phosphatase, PP2Cm, specifically binds the BCKD complex and induces dephosphorylation of Ser293 in the presence of BCKD substrates. Loss of PP2Cm completely abolished substrate-induced E1alpha dephosphorylation both in vitro and in vivo. PP2Cm-deficient mice exhibited BCAA catabolic defects and a metabolic phenotype similar to the intermittent or intermediate types of human maple syrup urine disease (MSUD), a hereditary disorder caused by defects in BCKD activity. These results indicate that PP2Cm is the endogenous BCKD phosphatase required for nutrient-mediated regulation of BCKD activity and suggest that defects in PP2Cm may be responsible for a subset of human MSUD.

Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

NASA Astrophysics Data System (ADS)

Kitadai, Norio

2015-12-01

Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments.

PubMed

Kitadai, Norio

2015-12-01

Alkaline hydrothermal systems have received considerable attention as candidates for the origin and evolution of life on the primitive Earth. Nevertheless, sufficient information has not yet been obtained for the thermodynamic properties of amino acids, which are necessary components for life, at high temperatures and alkaline pH. These properties were estimated using experimental high-temperature volume and heat capacity data reported in the literature for several amino acids, together with correlation algorithms and the revised Helgeson-Kirkham-Flowers (HKF) equations of state. This approach enabled determination of a complete set of the standard molal thermodynamic data and the revised HKF parameters for the 20 protein amino acids in their zwitterionic and ionization states. The obtained dataset was then used to evaluate the energetics of amino acid syntheses from simple inorganic precursors (CO2, H2, NH3 and H2S) in a simulated alkaline hydrothermal system on the Hadean Earth. Results show that mixing between CO2-rich seawater and the H2-rich hydrothermal fluid can produce energetically favorable conditions for amino acid syntheses, particularly in the lower-temperature region of such systems. Together with data related to the pH and temperature dependences of the energetics of amino acid polymerizations presented in earlier reports, these results suggest the following. Hadean alkaline hydrothermal settings, where steep pH and temperature gradients may have existed between cool, slightly acidic Hadean ocean water and hot, alkaline hydrothermal fluids at the vent-ocean interface, may be energetically the most suitable environment for the synthesis and polymerization of amino acids.

Increasing CO2 differentially affects essential and non-essential amino acid concentration of rice grains grown in cadmium-contaminated soils.

PubMed

Wu, Huibin; Song, Zhengguo; Wang, Xiao; Liu, Zhongqi; Tang, Shirong

2016-09-01

Environmental pollution by both ambient CO2 and heavy metals has been steadily increasing, but we do not know how fluctuating CO2 concentrations influence plant nutrients under high Cd pollution, especially in crops. Here, we studied the effects of elevated CO2 and Cd accumulation on proteins and amino acids in rice under Cd stress. In this pot experiment, we analyzed the amino-acid profile of 20 rice cultivars that accumulate Cd differently; the plants were grown in Cd-containing soils under ambient conditions and elevated CO2 levels. We found that although Cd concentrations appeared to be higher in most cultivars under elevated CO2 than under ambient CO2, the effect was significant only in seven cultivars. Combined exposure to Cd and elevated CO2 strongly decreased rice protein and amino acid profiles, including essential and non-essential amino acids. Under elevated CO2, the ratios of specific amino acids were either higher or lower than the optimal ratios provided by FAO/WHO, suggesting that CO2 may flatten the overall amino-acid profile, leading to an excess in some amino acids and deficiencies in others when the rice is consumed. Thus, Cd-tainted rice limits the concentration of essential amino acids in rice-based diets, and the combination with elevated CO2 further exacerbates the problem. Copyright © 2016 Elsevier Ltd. All rights reserved.

The Amino Acid Composition of the Sutter's Mill Carbonaceous Chondrite

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Burton, A. S.; Elsila, J. E.; Dworkin, J. P.; Yin, Q. Z.; Cooper, G.; Jenniskens, P.

2012-01-01

In contrast to the Murchison meteorite which had a complex distribution of amino acids with a total C2 to Cs amino acid abundance of approx.14,000 parts-per-billion (ppb) [2], the Sutters Mill meteorite was found to be highly depleted in amino acids. Much lower abundances (approx.30 to 180 ppb) of glycine, beta-alanine, L-alanine and L-serine were detected in SM2 above procedural blank levels indicating that this meteorite sample experienced only minimal terrestrial amino acid contamination after its fall to Earth. Carbon isotope measurements will be necessary to establish the origin of glycine and beta-alanine in SM2. Other non-protein amino acids that are rare on Earth, yet commonly found in other CM meteorites such as aaminoisobutyric acid (alpha-AIB) and isovaline, were not identified in SM2. However, traces of beta-AIB (approx.1 ppb) were detected in SM2 and could be" extraterrestrial in origin. The low abundances of amino acids in the Sutter's Mill meteorite is consistent with mineralogical evidence that at least some parts of the Sutter's Mill meteorite parent body experienced extensive aqueous and/or thermal alteration.

Amino acid nutrition of fishes: requirements and supplementation of diets

USGS Publications Warehouse

Ketola, H.G.

1982-01-01

The purpose of this paper is: (1) to make a concise review of the published dietary requirements of fishes for amino acids, (2) to describe recent findings at the Tunison Laboratory concerning amino acid nutrition of trout, (3) to review specific signs of deficiency of amino acids, and (4) to discuss use of the fish egg amino acid pattern as a guideline to formulating new feeds or studying amino acid requirements of fishes for which there is limited information on their quantitative requirements.

Gustatory sensation of (L)- and (D)-amino acids in humans.

PubMed

Kawai, Misako; Sekine-Hayakawa, Yuki; Okiyama, Atsushi; Ninomiya, Yuzo

2012-12-01

Amino acids are known to elicit complex taste, but most human psychophysical studies on the taste of amino acids have focused on a single basic taste, such as umami (savory) taste, sweetness, or bitterness. In this study, we addressed the potential relationship between the structure and the taste properties of amino acids by measuring the human gustatory intensity and quality in response to aqueous solutions of proteogenic amino acids in comparison to D-enantiomers. Trained subjects tasted aqueous solution of each amino acid and evaluated the intensities of total taste and each basic taste using a category-ratio scale. Each basic taste of amino acids showed the dependency on its hydrophobicity, size, charge, functional groups on the side chain, and chirality of the alpha carbon. In addition, the overall taste of amino acid was found to be the combination of basic tastes according to the partial structure. For example, hydrophilic non-charged middle-sized amino acids elicited sweetness, and L-enantiomeric hydrophilic middle-sized structure was necessary for umami taste. For example, L-serine had mainly sweet and minor umami taste, and D-serine was sweet. We further applied Stevens' psychophysical function to relate the total-taste intensity and the concentration, and found that the slope values depended on the major quality of taste (e.g., bitter large, sour small).

The Origin of Amino Acids in Lunar Regolith Samples

NASA Technical Reports Server (NTRS)

Cook, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K., Jr.

2016-01-01

We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5 ppb to 651.1 ppb in 6M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: -aminoisobutyric acid (AIB), D-and L-amino-n-butyric acid (-ABA), DL-amino-n-butyric acid, -amino-n-butyric acid, -alanine, and -amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic -ABA were present in some samples.

Enzymes involved in branched-chain amino acid metabolism in humans.

PubMed

Adeva-Andany, María M; López-Maside, Laura; Donapetry-García, Cristóbal; Fernández-Fernández, Carlos; Sixto-Leal, Cristina

2017-06-01

Branched-chain amino acids (leucine, isoleucine and valine) are structurally related to branched-chain fatty acids. Leucine is 2-amino-4-methyl-pentanoic acid, isoleucine is 2-amino-3-methyl-pentanoic acid, and valine is 2-amino-3-methyl-butanoic acid. Similar to fatty acid oxidation, leucine and isoleucine produce acetyl-coA. Additionally, leucine generates acetoacetate and isoleucine yields propionyl-coA. Valine oxidation produces propionyl-coA, which is converted into methylmalonyl-coA and succinyl-coA. Branched-chain aminotransferase catalyzes the first reaction in the catabolic pathway of branched-chain amino acids, a reversible transamination that converts branched-chain amino acids into branched-chain ketoacids. Simultaneously, glutamate is converted in 2-ketoglutarate. The branched-chain ketoacid dehydrogenase complex catalyzes the irreversible oxidative decarboxylation of branched-chain ketoacids to produce branched-chain acyl-coA intermediates, which then follow separate catabolic pathways. Human tissue distribution and function of most of the enzymes involved in branched-chain amino acid catabolism is unknown. Congenital deficiencies of the enzymes involved in branched-chain amino acid metabolism are generally rare disorders. Some of them are associated with reduced pyruvate dehydrogenase complex activity and respiratory chain dysfunction that may contribute to their clinical phenotype. The biochemical phenotype is characterized by accumulation of the substrate to the deficient enzyme and its carnitine and/or glycine derivatives. It was established at the beginning of the twentieth century that the plasma level of the branched-chain amino acids is increased in conditions associated with insulin resistance such as obesity and diabetes mellitus. However, the potential clinical relevance of this elevation is uncertain.

An amino acid depleted cell-free protein synthesis system for the incorporation of non-canonical amino acid analogs into proteins.

PubMed

Singh-Blom, Amrita; Hughes, Randall A; Ellington, Andrew D

2014-05-20

Residue-specific incorporation of non-canonical amino acids into proteins is usually performed in vivo using amino acid auxotrophic strains and replacing the natural amino acid with an unnatural amino acid analog. Herein, we present an efficient amino acid depleted cell-free protein synthesis system that can be used to study residue-specific replacement of a natural amino acid by an unnatural amino acid analog. This system combines a simple methodology and high protein expression titers with a high-efficiency analog substitution into a target protein. To demonstrate the productivity and efficacy of a cell-free synthesis system for residue-specific incorporation of unnatural amino acids in vitro, we use this system to show that 5-fluorotryptophan and 6-fluorotryptophan substituted streptavidin retain the ability to bind biotin despite protein-wide replacement of a natural amino acid for the amino acid analog. We envisage this amino acid depleted cell-free synthesis system being an economical and convenient format for the high-throughput screening of a myriad of amino acid analogs with a variety of protein targets for the study and functional characterization of proteins substituted with unnatural amino acids when compared to the currently employed in vivo methodologies. Copyright © 2014 Elsevier B.V. All rights reserved.

Terrestrial evolution of polymerization of amino acids - Heat to ATP

NASA Technical Reports Server (NTRS)

Fox, S. W.; Nakashima, T.

1981-01-01

Sets of amino acids containing sufficient trifunctional monomer are thermally polymerized at temperatures such as 65 deg; the amino acids order themselves. Various polymers have diverse catalytic activities. The polymers aggregate, in aqueous solution, to cell-like structures having those activities plus emergent properties, e.g. proliferatability. Polyamino acids containing sufficient lysine catalyze conversion of free amino acids, by ATP, to small peptides and a high molecular weight fraction. The lysine-rich proteinoid is active in solution, within suspensions of cell-like particles, or in other particles composed of lysine-rich proteinoid and homopolyribonucleotide. Selectivities are observed. An archaic polyamino acid prelude to coded protein synthesis is indicated.

Utilization of acidic α-amino acids as acyl donors: an effective stereo-controllable synthesis of aryl-keto α-amino acids and their derivatives.

PubMed

Wang, Lei; Murai, Yuta; Yoshida, Takuma; Okamoto, Masashi; Tachrim, Zetryana Puteri; Hashidoko, Yasuyuki; Hashimoto, Makoto

2014-05-16

Aryl-keto-containing α-amino acids are of great importance in organic chemistry and biochemistry. They are valuable intermediates for the construction of hydroxyl α-amino acids, nonproteinogenic α-amino acids, as well as other biofunctional components. Friedel-Crafts acylation is an effective method to prepare aryl-keto derivatives. In this review, we summarize the preparation of aryl-keto containing α-amino acids by Friedel-Crafts acylation using acidic α-amino acids as acyl-donors and Lewis acids or Brönsted acids as catalysts.

Synthesis, antiproliferative activity, and mechanism of action of a series of 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides

PubMed Central

Raffa, Demetrio; Maggio, Benedetta; Plescia, Fabiana; Cascioferro, Stella; Plescia, Salvatore; Raimondi, Maria Valeria; Daidone, Giuseppe; Tolomeo, Manlio; Grimaudo, Stefania; Di Cristina, Antonietta; Pipitone, Rosaria Maria; Bai, Ruoli; Hamel, Ernest

2011-01-01

Several new 2-{[(2E)-3-phenylprop-2-enoyl]amino}benzamides 12a–s and 17t–v were synthesized by stirring in pyridine the (E)-3-(2-R1-3-R2-4-R3-phenyl)acrylic acid chlorides 11c–k and 11t–v with the appropriate anthranilamide derivatives 10a–c or the 5-iodoanthranilic acid 13. Some of the synthesized compounds were evaluated for their in vitro antiproliferative activity against the full NCI tumor cell line panel derived from nine clinically isolated cancer types (leukemia, non-small cell lung, colon, CNS, melanoma, ovarian, renal, prostate and breast). COMPARE analysis, effects on tubulin polymerization in cells and with purified tubulin, and effects on cell cycle distribution for 17t, the most active of the series, indicate that these new antiproliferative compounds act as antitubulin agents. PMID:21530013

Characterizing amino-acid biosignatures amongst individuals with schizophrenia: a case-control study.

PubMed

Cao, Bing; Wang, Dongfang; Brietzke, Elisa; McIntyre, Roger S; Pan, Zihang; Cha, Danielle; Rosenblat, Joshua D; Zuckerman, Hannah; Liu, Yaqiong; Xie, Qing; Wang, Jingyu

2018-05-23

Amino acids and derivatives participate in the biosynthesis and downstream effects of numerous neurotransmitters. Variations in specific amino acids have been implicated in the pathophysiology of schizophrenia. Herein, we sought to compare levels of amino acids and derivatives between subjects with schizophrenia and healthy controls (HC). Two hundred and eight subjects with Diagnostic and Statistical Manual of Mental Disorders, Fourth Edition criteria (DSM-IV)-defined schizophrenia and 175 age- and sex-matched HC were enrolled. The levels of twenty-five amino acids and seven related derivatives were measured in plasma samples using hydrophilic interaction liquid chromatography (HILIC) liquid chromatography-tandem mass spectrometry (LC-MS). After controlling for age, sex and body mass index (BMI), four amino acids and derivatives (i.e., cysteine, GABA, glutamine and sarcosine) were observed to be higher in the schizophrenia group when compared with HC; seven amino acids and derivatives were lower in the schizophrenia group (i.e., arginine, L-ornithine, threonine, taurine, tryptophan, methylcysteine, and kynurenine). Statistically significant differences in plasma amino-acid profiles between subjects with first-episode vs. recurrent schizophrenia for aspartate and glutamine were also demonstrated using generalized linear models controlling for age, sex, and BMI. The differences in amino acids and derivatives among individuals with schizophrenia when compared to HC may represent underlying pathophysiology, including but not limited to dysfunctional proteinogenic processes, alterations in excitatory and inhibitory neurotransmission, changes in ammonia metabolism and the urea cycle. Taken together, amino-acid profiling may provide a novel stratification approach among individuals with schizophrenia.

Metabolizable energy values and amino acid availability of vetch (Vicia sativa) and ervil (Vicia ervilia) seeds soaked in water and acetic acid.

PubMed

Farran, M T; Barbour, G W; Uwayjan, M G; Ashkarian, V M

2001-07-01

In two experiments we evaluated the effect of water and acetic acid soaking on ME, apparent amino acid (AA) availability, and true AA availability of vetch (V) and ervil (E) seeds. In Experiment 1, the feedstuffs were untreated (U) V or coarsely ground V soaked in water (1:10, wt/vol) at 40 C for 72 h with a water change every 12 h (40WV), vetch soaked in 1% acetic acid for 24 h at 40 C (40AAV) or at room temperature (RTAAV), or dehulled soybean meal (SBM). In Experiment 2, E seeds were subjected to the same soaking methods, and the ingredients were UE, 40WE, 40AAE, RTAAE, and SBM. Each feedstuff was precision-fed to five individually caged mature ISA Brown roosters. A group of five roosters was used to correct for metabolic and endogenous energy and amino acid losses. The AME, AMEn, TME, and TMEn of UV and UE (in parentheses) were 2,558 (2,663), 2,840 (3,098), 3,026 (3,154), and 2,934 (3,176) kcal/kg DM, respectively, and were, in general, higher than those of SBM. The TMEn of V increased as a result of soaking in water or acetic acid, whereas that of E decreased in 40WE and RTAAE by 492 and 920 kcal/kg DM, respectively (P < 0.05). The apparent availability of most essential amino acids in UV and UE was lower (P < 0.05) than that of SBM. Acetic acid soaking of V, irrespective of temperature, and E at 40 C resulted in apparent AA availability similar to that of SBM except for Met. The true AA availability of V treated or not, and that of E soaked at 40 C, were similar to that of SBM. Results indicated that UV and UE are energy rich ingredients but detrimental to amino acid availability. Soaking the seeds in acetic acid at room temperature and at 40 C improved the nutritional value of V and E, respectively.

Real-time Measurements of Amino Acid and Protein Hydroperoxides Using Coumarin Boronic Acid*

PubMed Central

Michalski, Radoslaw; Zielonka, Jacek; Gapys, Ewa; Marcinek, Andrzej; Joseph, Joy; Kalyanaraman, Balaraman

2014-01-01

Hydroperoxides of amino acid and amino acid residues (tyrosine, cysteine, tryptophan, and histidine) in proteins are formed during oxidative modification induced by reactive oxygen species. Amino acid hydroperoxides are unstable intermediates that can further propagate oxidative damage in proteins. The existing assays (oxidation of ferrous cation and iodometric assays) cannot be used in real-time measurements. In this study, we show that the profluorescent coumarin boronic acid (CBA) probe reacts with amino acid and protein hydroperoxides to form the corresponding fluorescent product, 7-hydroxycoumarin. 7-Hydroxycoumarin formation was catalase-independent. Based on this observation, we have developed a fluorometric, real-time assay that is adapted to a multiwell plate format. This is the first report showing real-time monitoring of amino acid and protein hydroperoxides using the CBA-based assay. This approach was used to detect protein hydroperoxides in cell lysates obtained from macrophages exposed to visible light and photosensitizer (rose bengal). We also measured the rate constants for the reaction between amino acid hydroperoxides (tyrosyl, tryptophan, and histidine hydroperoxides) and CBA, and these values (7–23 m−1 s−1) were significantly higher than that measured for H2O2 (1.5 m−1 s−1). Using the CBA-based competition kinetics approach, the rate constants for amino acid hydroperoxides with ebselen, a glutathione peroxidase mimic, were also determined, and the values were within the range of 1.1–1.5 × 103 m−1 s−1. Both ebselen and boronates may be used as small molecule scavengers of amino acid and protein hydroperoxides. Here we also show formation of tryptophan hydroperoxide from tryptophan exposed to co-generated fluxes of nitric oxide and superoxide. This observation reveals a new mechanism for amino acid and protein hydroperoxide formation in biological systems. PMID:24928516

Boron Stress Activates the General Amino Acid Control Mechanism and Inhibits Protein Synthesis

PubMed Central

Uluisik, Irem; Kaya, Alaattin; Fomenko, Dmitri E.; Karakaya, Huseyin C.; Carlson, Bradley A.; Gladyshev, Vadim N.; Koc, Ahmet

2011-01-01

Boron is an essential micronutrient for plants, and it is beneficial for animals. However, at high concentrations boron is toxic to cells although the mechanism of this toxicity is not known. Atr1 has recently been identified as a boron efflux pump whose expression is upregulated in response to boron treatment. Here, we found that the expression of ATR1 is associated with expression of genes involved in amino acid biosynthesis. These mechanisms are strictly controlled by the transcription factor Gcn4 in response to boron treatment. Further analyses have shown that boron impaired protein synthesis by promoting phosphorylation of eIF2α in a Gcn2 kinase dependent manner. The uncharged tRNA binding domain (HisRS) of Gcn2 is necessary for the phosphorylation of eIF2α in the presence of boron. We postulate that boron exerts its toxic effect through activation of the general amino acid control system and inhibition of protein synthesis. Since the general amino acid control pathway is conserved among eukaryotes, this mechanism of boron toxicity may be of general importance. PMID:22114689

Amino acid repletion does not decrease muscle protein catabolism during hemodialysis.

PubMed

Raj, Dominic S C; Adeniyi, Oladipo; Dominic, Elizabeth A; Boivin, Michel A; McClelland, Sandra; Tzamaloukas, Antonios H; Morgan, Nancy; Gonzales, Lawrence; Wolfe, Robert; Ferrando, Arny

2007-06-01

Intradialytic protein catabolism is attributed to loss of amino acids in the dialysate. We investigated the effect of amino acid infusion during hemodialysis (HD) on muscle protein turnover and amino acid transport kinetics by using stable isotopes of phenylalanine, leucine, and lysine in eight patients with end-stage renal disease (ESRD). Subjects were studied at baseline (pre-HD), 2 h of HD without amino acid infusion (HD-O), and 2 h of HD with amino acid infusion (HD+AA). Amino acid depletion during HD-O augmented the outward transport of amino acids from muscle into the vein. Increased delivery of amino acids to the leg during HD+AA facilitated the transport of amino acids from the artery into the intracellular compartment. Increase in muscle protein breakdown was more than the increase in synthesis during HD-O (46.7 vs. 22.3%, P < 0.001). Net balance (nmol.min(-1).100 ml (-1)) was more negative during HD-O compared with pre-HD (-33.7 +/- 1.5 vs. -6.0 +/- 2.3, P < 0.001). Despite an abundant supply of amino acids, the net balance (-16.9 +/- 1.8) did not switch from net release to net uptake. HD+AA induced a proportional increase in muscle protein synthesis and catabolism. Branched chain amino acid catabolism increased significantly from baseline during HD-O and did not decrease during HD+AA. Protein synthesis efficiency, the fraction of amino acid in the intracellular pool that is utilized for muscle protein synthesis decreased from 42.1% pre-HD to 33.7 and 32.6% during HD-O and HD+AA, respectively (P < 0.01). Thus amino acid repletion during HD increased muscle protein synthesis but did not decrease muscle protein breakdown.

Removal of acidic or basic α-amino acids in water by poorly water soluble scandium complexes.

PubMed

Hayashi, Nobuyuki; Jin, Shigeki; Ujihara, Tomomi

2012-11-02

To recognize α-amino acids with highly polar side chains in water, poorly water soluble scandium complexes with both Lewis acidic and basic portions were synthesized as artificial receptors. A suspension of some of these receptor molecules in an α-amino acid solution could remove acidic and basic α-amino acids from the solution. The compound most efficient at preferentially removing basic α-amino acids (arginine, histidine, and lysine) was the receptor with 7,7'-[1,3-phenylenebis(carbonylimino)]bis(2-naphthalenesulfonate) as the ligand. The neutral α-amino acids were barely removed by these receptors. Removal experiments using a mixed amino acid solution generally gave results similar to those obtained using solutions containing a single amino acid. The results demonstrated that the scandium complex receptors were useful for binding acidic and basic α-amino acids.

Urinary amino acid analysis: a comparison of iTRAQ-LC-MS/MS, GC-MS, and amino acid analyzer.

PubMed

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J

2009-07-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27+/-5.22, 21.18+/-10.94, and 18.34+/-14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39+/-5.35, 6.23+/-3.84, and 35.37+/-29.42. Both GC-MS and iTRAQ-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines.

Transport of amino acids in the kidney.

PubMed

Makrides, Victoria; Camargo, Simone M R; Verrey, François

2014-01-01

Amino acids are the building blocks of proteins and key intermediates in the synthesis of biologically important molecules, as well as energy sources, neurotransmitters, regulators of cellular metabolism, etc. The efficient recovery of amino acids from the primary filtrate is a well-conserved key role of the kidney proximal tubule. Additionally, renal metabolism participates in the whole body disposition of amino acids. Therefore, a wide array of axially heterogeneously expressed transporters is localized on both epithelial membranes. For transepithelial transport, luminal uptake, which is carried out mainly by active symporters, is coupled with a mostly passive basolateral efflux. Many transporters require partner proteins for appropriate localization, or to modulate transporter activity, and/or increase substrate supply. Interacting proteins include cell surface antigens (CD98), endoplasmic reticulum proteins (GTRAP3-18 or 41), or enzymes (ACE2 and aminopeptidase N). In the past two decades, the molecular identification of transporters has led to significant advances in our understanding of amino acid transport and aminoacidurias arising from defects in renal transport. Furthermore, the three-dimensional crystal structures of bacterial homologues have been used to yield new insights on the structure and function of mammalian transporters. Additionally, transgenic animal models have contributed to our understanding of the role of amino acid transporters in the kidney and other organs and/or at critical developmental stages. Progress in elucidation of the renal contribution to systemic amino acid homeostasis requires further integration of kinetic, regulatory, and expression data of amino acid transporters into our understanding of physiological regulatory networks controlling metabolism. © 2014 American Physiological Society.

Occurrence of the (2R,3S)-Isomer of 2-Amino-3,4-dihydroxybutanoic Acid in the Mushroom Hypsizygus marmoreus.

PubMed

Ito, Tomokazu; Yu, Zhuoer; Yoshino, Issei; Hirozawa, Yurina; Yamamoto, Kana; Shinoda, Kiyotugu; Watanabe, Akira; Hemmi, Hisashi; Asada, Yasuhiko; Yoshimura, Tohru

2017-08-02

Here, we report the occurrence of the (2R,3S)-isomer of 2-amino-3,4-dihydroxybutanoic acid (d-ADHB) in the fruiting body of an edible mushroom, Hypsizygus marmoreus. This is an unusual example of the accumulation of a d-amino acid whose enantiomer is not a proteinogenic amino acid. We show that d-ADHB occurs specifically in the mushroom H. marmoreus. Other edible mushrooms examined, including Pholiota microspora, Pleurotus eryngii, Mycena chlorophos, Sparassis crispa, Grifola frondosa, Pleurotus ostreatus, and Flammulina velutipes, do not contain detectable levels of d-ADHB. The concentration of d-ADHB in the fruiting body of H. marmoreus is relatively high (approximately 1.3 mg/g of fruiting body) and is comparable to the concentration of some of the most abundant free proteinogenic amino acids. Quantitative analysis of d-ADHB during fruiting body development demonstrated that the amino acid is synthesized during the fruiting body formation period. The absence of the putative precursors of d-ADHB, the (2S,3S)-isomer of ADHB and 2-oxo-tetronate, and the enzyme activities of d-ADHB racemase (2-epimerase) and transaminase suggested that d-ADHB is synthesized by a unique mechanism in this organism. Our data also suggested that the lack of or low expression of a d-ADHB degradation enzyme is a key determinant of d-ADHB accumulation in H. marmoreus.

Synthesis of new kojic acid based unnatural α-amino acid derivatives.

PubMed

Balakrishna, C; Payili, Nagaraju; Yennam, Satyanarayana; Uma Devi, P; Behera, Manoranjan

2015-11-01

An efficient method for the preparation of kojic acid based α-amino acid derivatives by alkylation of glycinate schiff base with bromokojic acids have been described. Using this method, mono as well as di alkylated kojic acid-amino acid conjugates have been prepared. This is the first synthesis of C-linked kojic acid-amino acid conjugate where kojic acid is directly linked to amino acid through a C-C bond. Copyright © 2015 Elsevier Ltd. All rights reserved.

Gene expression of amino acid transporter in pigeon (Columbia livia) intestine during post-hatch development and its correlation with amino acid in pigeon milk.

PubMed

Zhang, X Y; Zhang, N N; Wan, X P; Li, L L; Zou, X T

2017-05-01

This study was conducted to evaluate gene expression of the amino acid transporter in post-hatch pigeon small intestine and the association of pigeon milk amino acid with the above transporter's gene expression. A total of 48 pigeon breeding families were randomly allocated to 8 groups of 6 replicates of one parental pigeon pair and 2 squabs. Samples of pigeon milk and duodenum, jejunum, and ileum were collected on d 1, 2, 3, 4, 6, 8, 10, and 14 post hatch. The results showed that levels of crude protein (8.93 to 15.56%) were highest in pigeon milk on an air-dry basis. Amino acid content in pigeon milk remained constant in the first 4 d, declined abruptly at d 6, then increased dramatically from d 8 to 14. There was a significant effect of interaction between age and intestinal segments on those amino acid transporters gene expression. mRNA abundance of ATB0'+, SNAT-2, LAT-4, rBAT, b0'+AT, EAAT-3 and PAT-1 was highest in the ileum; B0AT1, asc-1, and IMINO were predominate in the jejunum; and CAT-1 and y+LAT2 were greatest in the duodenum. Age-related changes of amino acid transporter mRNA was inconsistent. mRNA levels of SNAT-2, rBAT, y+LAT2, b0'+AT, and EAAT-3 ascended with age, whereas that of asc-1, CAT-1, and IMINO diminished significantly. Levels of B0AT1 and PAT-1 mRNA abundance were minimized at d 6. However, few correlations were found between pigeon milk amino acid and the amino acid transporter gene expressions in squab small intestine. Our findings provide a comprehensive elaboration on ontogeny of the amino acid transporter in post-hatch pigeon intestine. © 2016 Poultry Science Association Inc.

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.

Characterization of the Candida albicans Amino Acid Permease Family: Gap2 Is the Only General Amino Acid Permease and Gap4 Is an S-Adenosylmethionine (SAM) Transporter Required for SAM-Induced Morphogenesis.

PubMed

Kraidlova, Lucie; Schrevens, Sanne; Tournu, Hélène; Van Zeebroeck, Griet; Sychrova, Hana; Van Dijck, Patrick

2016-01-01

Amino acids are key sources of nitrogen for growth of Candida albicans . In order to detect and take up these amino acids from a broad range of different and changing nitrogen sources inside the host, this fungus must be able to adapt via its expression of genes for amino acid uptake and further metabolism. We analyzed six C. albicans putative general amino acid permeases based on their homology to the Saccharomyces cerevisiae Gap1 general amino acid permease. We generated single- and multiple-deletion strains and found that, based on growth assays and transcriptional or posttranscriptional regulation, Gap2 is the functional orthologue to Sc Gap1, with broad substrate specificity. Expression analysis showed that expression of all GAP genes is under control of the Csy1 amino acid sensor, which is different from the situation in S. cerevisiae , where the expression of ScGAP1 is not regulated by Ssy1. We show that Gap4 is the functional orthologue of Sc Sam3, the only S -adenosylmethionine (SAM) transporter in S. cerevisiae , and we report that Gap4 is required for SAM-induced morphogenesis. IMPORTANCE Candida albicans is a commensal organism that can thrive in many niches in its human host. The environmental conditions at these different niches differ quite a bit, and this fungus must be able to sense these changes and adapt its metabolism to them. Apart from glucose and other sugars, the uptake of amino acids is very important. This is underscored by the fact that the C. albicans genome encodes 6 orthologues of the Saccharomyces. cerevisiae general amino acid permease Gap1 and many other amino acid transporters. In this work, we characterize these six permeases and we show that C. albicans Gap2 is the functional orthologue of Sc Gap1 and that C. albicans Gap4 is an orthologue of Sc Sam3, an S -adenosylmethionine (SAM) transporter. Furthermore, we show that Gap4 is required for SAM-induced morphogenesis, an important virulence factor of C. albicans .

Amino Acid Properties Conserved in Molecular Evolution

PubMed Central

Rudnicki, Witold R.; Mroczek, Teresa; Cudek, Paweł

2014-01-01

That amino acid properties are responsible for the way protein molecules evolve is natural and is also reasonably well supported both by the structure of the genetic code and, to a large extent, by the experimental measures of the amino acid similarity. Nevertheless, there remains a significant gap between observed similarity matrices and their reconstructions from amino acid properties. Therefore, we introduce a simple theoretical model of amino acid similarity matrices, which allows splitting the matrix into two parts – one that depends only on mutabilities of amino acids and another that depends on pairwise similarities between them. Then the new synthetic amino acid properties are derived from the pairwise similarities and used to reconstruct similarity matrices covering a wide range of information entropies. Our model allows us to explain up to 94% of the variability in the BLOSUM family of the amino acids similarity matrices in terms of amino acid properties. The new properties derived from amino acid similarity matrices correlate highly with properties known to be important for molecular evolution such as hydrophobicity, size, shape and charge of amino acids. This result closes the gap in our understanding of the influence of amino acids on evolution at the molecular level. The methods were applied to the single family of similarity matrices used often in general sequence homology searches, but it is general and can be used also for more specific matrices. The new synthetic properties can be used in analyzes of protein sequences in various biological applications. PMID:24967708

Urinary Amino Acid Analysis: A Comparison of iTRAQ®-LC-MS/MS, GC-MS, and Amino Acid Analyzer

PubMed Central

Kaspar, Hannelore; Dettmer, Katja; Chan, Queenie; Daniels, Scott; Nimkar, Subodh; Daviglus, Martha L.; Stamler, Jeremiah; Elliott, Paul; Oefner, Peter J.

2009-01-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatography-tandem mass spectrometry (LC-MS/MS) of propyl chloroformate and iTRAQ® derivatized amino acids, respectively, to conventional amino acid analysis. The GC-MS method builds on the direct derivatization of amino acids in diluted urine with propyl chloroformate, GC separation and mass spectrometric quantification of derivatives using stable isotope labeled standards. The LC-MS/MS method requires prior urinary protein precipitation followed by labeling of urinary and standard amino acids with iTRAQ® tags containing different cleavable reporter ions distinguishable by MS/MS fragmentation. Means and standard deviations of percent technical error (%TE) computed for 20 amino acids determined by amino acid analyzer, GC-MS, and iTRAQ®-LC-MS/MS analyses of 33 duplicate and triplicate urine specimens were 7.27±5.22, 21.18±10.94, and 18.34±14.67, respectively. Corresponding values for 13 amino acids determined in a second batch of 144 urine specimens measured in duplicate or triplicate were 8.39±5.35, 6.23±3.84, and 35.37±29.42. Both GC-MS and iTRAQ®-LC-MS/MS are suited for high-throughput amino acid analysis, with the former offering at present higher reproducibility and completely automated sample pretreatment, while the latter covers more amino acids and related amines. PMID:19481989

Identification of critical amino acids in the IgE epitopes of Ric c 1 and Ric c 3 and the application of glutamic acid as an IgE blocker.

PubMed

Deus-de-Oliveira, Natalia; Felix, Shayany P; Carrielo-Gama, Camila; Fernandes, Keysson V; DaMatta, Renato Augusto; Machado, Olga L T

2011-01-01

The allergenicity of Ricinus communis L. (castor bean, Euphorbiaceae) is associated with components of its seeds and pollen. Castor bean allergy has been described not only in laboratory workers, but also in personnel working in oil processing mills, fertilizer retail, the upholstery industry and other industrial fields. In the present study, we describe the critical amino acids in the IgE-binding epitopes in Ric c 1 and Ric c 3, two major allergens of R. communis. In addition, we also investigate the cross-reactivity between castor bean and some air and food allergen extracts commonly used in allergy diagnosis. The IgE reactivity of human sera from atopic patients was screened by immune-dot blot against castor bean allergens. Allergenic activity was evaluated in vitro using a rat mast cell activation assay and by ELISA. Cross-reactivity was observed between castor bean allergens and extracts from shrimp, fish, gluten, wheat, soybean, peanut, corn, house dust, tobacco and airborne fungal allergens. We observed that treatment of rat and human sera (from atopic patients) with glutamic acid reduced the IgE-epitope interaction. The identification of glutamic acid residues with critical roles in IgE-binding to Ric c 3 and Ric c 1 support the potential use of free amino acids in allergy treatment.

40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

Code of Federal Regulations, 2010 CFR

2010-07-01

... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3,3â²-methyl-enebis [6...

40 CFR 721.1725 - Benzoic acid, 3,3′-methyl-enebis [6 amino-, di-2-propenyl ester.

Code of Federal Regulations, 2011 CFR

2011-07-01

... Significant New Uses for Specific Chemical Substances § 721.1725 Benzoic acid, 3,3′-methyl-enebis [6 amino..., Benzoic acid, 3,3′-methylenebis [6 amino-, di-2-propenyl ester. (2) The significant new uses are: (i) Any... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3,3â²-methyl-enebis [6...

Seq2Logo: a method for construction and visualization of amino acid binding motifs and sequence profiles including sequence weighting, pseudo counts and two-sided representation of amino acid enrichment and depletion

PubMed Central

Thomsen, Martin Christen Frølund; Nielsen, Morten

2012-01-01

Seq2Logo is a web-based sequence logo generator. Sequence logos are a graphical representation of the information content stored in a multiple sequence alignment (MSA) and provide a compact and highly intuitive representation of the position-specific amino acid composition of binding motifs, active sites, etc. in biological sequences. Accurate generation of sequence logos is often compromised by sequence redundancy and low number of observations. Moreover, most methods available for sequence logo generation focus on displaying the position-specific enrichment of amino acids, discarding the equally valuable information related to amino acid depletion. Seq2logo aims at resolving these issues allowing the user to include sequence weighting to correct for data redundancy, pseudo counts to correct for low number of observations and different logotype representations each capturing different aspects related to amino acid enrichment and depletion. Besides allowing input in the format of peptides and MSA, Seq2Logo accepts input as Blast sequence profiles, providing easy access for non-expert end-users to characterize and identify functionally conserved/variable amino acids in any given protein of interest. The output from the server is a sequence logo and a PSSM. Seq2Logo is available at http://www.cbs.dtu.dk/biotools/Seq2Logo (14 May 2012, date last accessed). PMID:22638583

40 CFR 721.5280 - 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, coupled with diazotized 4-butylbenzenamine...

Code of Federal Regulations, 2011 CFR

2011-07-01

... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-5-hydroxy... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, coupled with diazotized 4-butylbenzenamine, diazotized 4,4â²-cyclohexylidenebis...

40 CFR 721.5280 - 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, coupled with diazotized 4-butylbenzenamine...

Code of Federal Regulations, 2010 CFR

2010-07-01

... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-5-hydroxy... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2,7-Naphthalenedisulfonic acid, 4-amino-5-hydroxy-, coupled with diazotized 4-butylbenzenamine, diazotized 4,4â²-cyclohexylidenebis...

Increased ubiquitination and reduced plasma membrane trafficking of placental amino acid transporter SNAT-2 in human IUGR.

PubMed

Chen, Yi-Yung; Rosario, Fredrick J; Shehab, Majida Abu; Powell, Theresa L; Gupta, Madhulika B; Jansson, Thomas

2015-12-01

Placental amino acid transport is decreased in intrauterine growth restriction (IUGR); however, the underlying mechanisms remain largely unknown. We have shown that mechanistic target of rapamycin (mTOR) signalling regulates system A amino acid transport by modulating the ubiquitination and plasma membrane trafficking of sodium-coupled neutral amino acid transporter 2 (SNAT-2) in cultured primary human trophoblast cells. We hypothesize that IUGR is associated with (1) inhibition of placental mTORC1 and mTORC2 signalling pathways, (2) increased amino acid transporter ubiquitination in placental homogenates and (3) decreased protein expression of SNAT-2 in the syncytiotrophoblast microvillous plasma membrane (MVM). To test this hypothesis, we collected placental tissue and isolated MVM from women with pregnancies complicated by IUGR (n=25) and gestational age-matched women with appropriately grown control infants (n=19, birth weights between the twenty-fifth to seventy-fifth percentiles). The activity of mTORC1 and mTORC2 was decreased whereas the protein expression of the ubiquitin ligase NEDD4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2; +72%, P<0.0001) and the ubiquitination of SNAT-2 (+180%, P<0.05) were increased in homogenates of IUGR placentas. Furthermore, IUGR was associated with decreased system A amino acid transport activity (-72%, P<0.0001) and SNAT-1 (-42%, P<0.05) and SNAT-2 (-31%, P<0.05) protein expression in MVM. In summary, these findings are consistent with the possibility that decreased placental mTOR activity causes down-regulation of placental system A activity by shifting SNAT-2 trafficking towards proteasomal degradation, thereby contributing to decreased fetal amino acid availability and restricted fetal growth in IUGR. © 2015 Authors; published by Portland Press Limited.

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.

Amino Acid Crossword Puzzle

ERIC Educational Resources Information Center

Sims, Paul A.

2011-01-01

Learning the 20 standard amino acids is an essential component of an introductory course in biochemistry. Later in the course, the students study metabolism and learn about various catabolic and anabolic pathways involving amino acids. Learning new material or concepts often is easier if one can connect the new material to what one already knows;…

Present Global Situation of Amino Acids in Industry.

PubMed

Tonouchi, Naoto; Ito, Hisao

At present, amino acids are widely produced and utilized industrially. Initially, monosodium glutamate (MSG) was produced by extraction from a gluten hydrolysate. The amino acid industry started using the residual of the lysate. The discovery of the functions of amino acids has led to the expansion of their field of use. In addition to seasoning and other food use, amino acids are used in many fields such as animal nutrients, pharmaceuticals, and cosmetics. On the other hand, the invention of the glutamate fermentation process, followed by the development of fermentation methods for many other amino acids, is no less important. The supply of these amino acids at a low price is very essential for their industrial use. Most amino acids are now produced by fermentation. The consumption of many amino acids such as MSG or feed-use amino acids is still rapidly increasing.

Novel families of vacuolar amino acid transporters.

PubMed

Sekito, Takayuki; Fujiki, Yuki; Ohsumi, Yoshinori; Kakinuma, Yoshimi

2008-08-01

Amino acids are compartmentalized in the vacuoles of microorganisms and plants. In Saccharomyces cerevisiae, basic amino acids accumulate preferentially into vacuoles but acidic amino acids are almost excluded from them. This indicates that selective machineries operate at the vacuolar membrane. The members of the amino acid/auxin permease family and the major facilitator superfamily involved in the vacuolar compartmentalization of amino acids have been recently identified in studies using S. cerevisiae. Homologous genes for these transporters are also found in plant and mammalian genomes. The physiological significance in response to nitrogen starvation can now be discussed. (c) 2008 IUBMB

Formation of amino acids and nucleic acid constituents from simulated primitive planetary atmospheres by irradiation with high-energy protons

NASA Astrophysics Data System (ADS)

Kobayashi, K.; Yamanashi, H.; Ohashi, A.; Kaneko, T.; Miyakawa, S.; Saito, T.

It is suggested that primitive Earth atmosphere was only slightly reduced, which w as composed of carbon dioxide, carbon monoxide, nitrogen and water. It has been shown that bioorganic compounds can be hardly formed by energies as UV light, heat and spark discharges. We therefore examined possible formation pat hways of bioorganic compounds in the primitive E arth. A mixt ure of carbon monoxide, nitrogen and water was irradiated with high-energy prot ons generated by a van de Graaff accelerator, whi c h simulated an action of cosm ic rays. Aqueous solution of the product was hydr olyzed, and then analyzed by chromatography and mass spectrometry. A wide variety of amino acids and uracil, one of the nucle ic acid bases, wer e identified. Ribose, the RNA sugar, has not been identified, but formation of reducing polyols was suggested. A mino acids and uracil were also formed from a mixture of carbo n dioxide, carbon monoxide, nitrogen and water, and their yields correlated to the ratio of carbon monoxide and nitrogen in the mixture. Since a certain percentage of carbon monoxide could be expected to be in it [1], cosmic radiation can be regarded as an effective energ so urce for prebiotic formation of life's building blocks in they primitive Earth [2]. In the conventional scenario of chemical evolution, amino acids were formed in t he primitive ocean from such intermediates as HCN an d HCHO formed in t he atmosphere. T his scenario seem s not to be possible due to the following reasons: (1) The irradiation products were quit e complex organic com pound s whose molecular weights were ca. 1000, and they gave amino acids after hydrolysis. (2) Energy yields of amino ac ids in the hydrolysates were comparable to those of HCN and HCHO in the irradiation pro duct s. (3) Irradiation products from a mixture of carbon monoxide and nitrogen without water als o gave amino acids aft er hydrolysis. T hes e observations strongly sugge s t e d that complex precursors of bioor ganic com

Synthesis and chirality of amino acids under interstellar conditions.

PubMed

Giri, Chaitanya; Goesmann, Fred; Meinert, Cornelia; Evans, Amanda C; Meierhenrich, Uwe J

2013-01-01

Amino acids are the fundamental building blocks of proteins, the biomolecules that provide cellular structure and function in all living organisms. A majority of amino acids utilized within living systems possess pre-specified orientation geometry (chirality); however the original source for this specific orientation remains uncertain. In order to trace the chemical evolution of life, an appreciation of the synthetic and evolutional origins of the first chiral amino acids must first be gained. Given that the amino acids in our universe are likely to have been synthesized in molecular clouds in interstellar space, it is necessary to understand where and how the first synthesis might have occurred. The asymmetry of the original amino acid synthesis was probably the result of exposure to chiral photons in the form of circularly polarized light (CPL), which has been detected in interstellar molecular clouds. This chirality transfer event, from photons to amino acids, has been successfully recreated experimentally and is likely a combination of both asymmetric synthesis and enantioselective photolysis. A series of innovative studies have reported successful simulation of these environments and afforded production of chiral amino acids under realistic circumstellar and interstellar conditions: irradiation of interstellar ice analogues (CO, CO2, NH3, CH3OH, and H2O) with circularly polarized ultraviolet photons at low temperatures does result in enantiomer enriched amino acid structures (up to 1.3% ee). This topical review summarizes current knowledge and recent discoveries about the simulated interstellar environments within which amino acids were probably formed. A synopsis of the COSAC experiment onboard the ESA cometary mission ROSETTA concludes this review: the ROSETTA mission will soft-land on the nucleus of the comet 67P/Churyumov-Gerasimenko in November 2014, anticipating the first in situ detection of asymmetric organic molecules in cometary ices.

New Inducible Nitric Oxide Synthase and Cyclooxygenase-2 Inhibitors, Nalidixic Acid Linked to Isatin Schiff Bases via Certain l-Amino Acid Bridges.

PubMed

Naglah, Ahmed M; Ahmed, Atallah F; Wen, Zhi-Hong; Al-Omar, Mohamed A; Amr, Abd El-Galil E; Kalmouch, Atef

2016-04-15

A series of new Schiff bases were synthesized by condensation of isatins with the nalidixic acid-l-amino acid hydrazides. Prior to hydrazide formation, a peptide linkage has been prepared via coupling of nalidixic acid with appropriate l-amino acid methyl esters to yield 3a-c. The chemical structures of the new Schiff bases (5b and 5d-h) were confirmed by means of IR, NMR, mass spectroscopic, and elemental analyses. The anti-inflammatory activity of these Schiff bases was evaluated via measurement of the expressed inducible nitric oxide synthase (iNOS) and cyclooxygenase-2 (COX-2) in the lipopolysaccharide (LPS)-stimulated RAW264.7 macrophage cells model. The Schiff bases exhibited significant dual inhibitory effect against the induction of the pro-inflammatory iNOS and COX-2 proteins with variable potencies. However, they strongly down-regulated the iNOS expression to the level of 16.5% ± 7.4%-42.2% ± 19.6% compared to the effect on COX-2 expression (<56.4% ± 3.1% inhibition) at the same concentration (10 μM). The higher iNOS inhibition activity of the tested Schiff bases, relative to that of COX-2, seems to be a reflection of the combined suppressive effects exerted by their nalidixic acid, isatins (4a-c), and l-amino acid moieties against iNOS expression. These synthesized nalidixic acid-l-amino acid-isatin conjugates can be regarded as a novel class of anti-inflammatory antibacterial agents.

Free amino acids in spider hemolymph.

PubMed

Tillinghast, Edward K; Townley, Mark A

2008-11-01

We examined the free amino acid composition of hemolymph from representatives of five spider families with an interest in knowing if the amino acid profile in the hemolymph of orb-web-building spiders reflects the high demands for small organic compounds in the sticky droplets of their webs. In nearly all analyses, on both orb and non-orb builders, glutamine was the most abundant free amino acid. Glycine, taurine, proline, histidine, and alanine also tended to be well-represented in orb and non-orb builders. While indications of taxon-specific differences in amino acid composition were observed, it was not apparent that two presumptive precursors (glutamine, taurine) of orb web sticky droplet compounds were uniquely enriched in araneids (orb builders). However, total amino acid concentrations were invariably highest in the araneids and especially so in overwintering juveniles, even as several of the essential amino acids declined during this winter diapause. Comparing the data from this study with those from earlier studies revealed a number of discrepancies. The possible origins of these differences are discussed.

Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis.

PubMed

Wilson, Fiona A; Suryawan, Agus; Orellana, Renán A; Nguyen, Hanh V; Jeyapalan, Asumthia S; Gazzaneo, Maria C; Davis, Teresa A

2008-10-01

Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 microg x kg(-1) x day(-1)) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P<0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P<0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1.eIF4E complex association, and increased active eIF4E.eIF4G complex formation (P<0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex.

Protein and Essential Amino Acids to Protect Musculoskeletal Health during Spaceflight: Evidence of a Paradox?

PubMed Central

Hackney, Kyle J.; English, Kirk L.

2014-01-01

Long-duration spaceflight results in muscle atrophy and a loss of bone mineral density. In skeletal muscle tissue, acute exercise and protein (e.g., essential amino acids) stimulate anabolic pathways (e.g., muscle protein synthesis) both independently and synergistically to maintain neutral or positive net muscle protein balance. Protein intake in space is recommended to be 12%–15% of total energy intake (≤1.4 g∙kg−1∙day−1) and spaceflight is associated with reduced energy intake (~20%), which enhances muscle catabolism. Increasing protein intake to 1.5–2.0 g∙kg−1∙day−1 may be beneficial for skeletal muscle tissue and could be accomplished with essential amino acid supplementation. However, increased consumption of sulfur-containing amino acids is associated with increased bone resorption, which creates a dilemma for musculoskeletal countermeasures, whereby optimizing skeletal muscle parameters via essential amino acid supplementation may worsen bone outcomes. To protect both muscle and bone health, future unloading studies should evaluate increased protein intake via non-sulfur containing essential amino acids or leucine in combination with exercise countermeasures and the concomitant influence of reduced energy intake. PMID:25370374

Dihydrotestosterone stimulates amino acid uptake and the expression of LAT2 in mouse skeletal muscle fibres through an ERK1/2-dependent mechanism

PubMed Central

Hamdi, M M; Mutungi, G

2011-01-01

Abstract Dihydrotestosterone (DHT) has acute/non-genomic actions in adult mammalian skeletal muscles whose physiological functions are still poorly understood. Therefore, the primary aim of this study was to investigate the acute/non-genomic effects of DHT on amino acid uptake as well as the cellular signal transduction events underlying these actions in mouse fast- and slow-twitch skeletal muscle fibre bundles. 14C-Labelled amino acids were used to investigate the effects of DHT and testosterone (T) on amino acid uptake and pharmacological interventions were used to determine the cellular signal transduction events mediating these actions. While T had no effect on the uptake of isoleucine (Ile) and α-methylaminoisobutyric acid (MeAIB) in both fibre types, DHT increased their uptake in the fast-twitch fibre bundles. This effect was reversed by inhibitors of protein translation, the epidermal growth factor receptor (EGFR), system A, system L, mTOR and MEK. However, it was relatively insensitive to inhibitors of transcription, androgen receptors and PI3K/Akt. Additionally, DHT treatment increased the expression of LAT2 and the phosphorylation of the EGFR in the fast-twitch fibre bundles and that of ERK1/2, RSK1/2 and ATF2 in both fibre types. Also, it decreased the phosphorylation of eEF2 and increased the incorporation of Ile into proteins in both fibre types. Most of these effects were reversed by EGFR and MEK inhibitors. From these findings we suggest that another physiological function of the acute/non-genomic actions of DHT in isolated mammalian skeletal muscle fibres is to stimulate amino acid uptake. This effect is mediated through the EGFR and involves the activation of the MAPK pathway and an increase in LAT2 expression. PMID:21606113

Branched-Chain Amino Acids Are the Primary Limiting Amino Acids in the Diets of Endurance-Trained Men after a Bout of Prolonged Exercise.

PubMed

Kato, Hiroyuki; Suzuki, Katsuya; Bannai, Makoto; Moore, Daniel R

2018-05-09

The indicator amino acid oxidation (IAAO) method estimates the protein intake required to maximize whole-body protein synthesis and identify the daily protein requirement in a variety of populations. However, it is unclear whether the greater requirements for endurance athletes previously determined by the IAAO reflect an increased demand for all or only some amino acids. The aim of this study was to determine the primary rate-limiting amino acids in endurance-trained athletes after prolonged exercise, by measuring the oxidation of ingested [1-13C]phenylalanine in response to variable amino acid intake. Five endurance-trained men (means ± SDs: age, 26 ± 7 y; body weight, 66.9 ± 9.5 kg; maximal oxygen consumption, 63.3 ± 4.3 mL · kg-1 · min-1) performed 5 trials that involved 2 d of controlled diet (1.4 g protein · kg-1 · d-1) and running (10 km on day 1 and 5 km on day 2) prior to performing an acute bout of endurance exercise (20-km treadmill run) on day 3. During recovery on day 3, participants consumed test diets as 8 isocaloric hourly meals providing sufficient energy and carbohydrate but a variable amino acid intake. The test diets, consumed in random order, were deficient (BASE: 0.8 g · kg-1 · d-1) and sufficient (SUF; 1.75 g · kg-1 · d-1) amino acid diets modeled after egg protein, and BASE supplemented with branched-chain amino acids (BCAA diet; 1.03 g · kg-1 · d-1), essential amino acids (EAA diet; 1.23 g · kg-1 · d-1), or nonessential amino acids (NEAA diet; 1.75 g · kg-1 · d-1). Whole-body phenylalanine flux (Q), 13CO2 excretion (F13CO2), and phenylalanine oxidation (OX) were determined according to standard IAAO methodology. There was no effect of amino acid intake on Q (P = 0.43). F13CO2 was significantly (all P < 0.01) lower than BASE for the BCAA (∼32%), EAA (∼31%), and SUF (∼36%) diet treatments. F13CO2 for the NEAA diet was ∼18% lower than for BASE (P < 0.05) but ∼28% greater than for SUF (P < 0

Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

NASA Technical Reports Server (NTRS)

Amashukeli, Xenia; Pelletier, Christine C.; Kirby, James P.; Grunthaner, Frank J.

2007-01-01

Amino acids are considered organic molecular indicators in the search for extant and extinct life in the Solar System. Extraction of these molecules from a particulate solid matrix, such as Martian regolith, will be critical to their in situ detection and analysis. The goals of this study were to optimize a laboratory amino acid extraction protocol by quantitatively measuring the yields of extracted amino acids as a function of liquid water temperature and sample extraction time and to compare the results to the standard HCl vapor- phase hydrolysis yields for the same soil samples. Soil samples from the Yungay region of the Atacama Desert ( Martian regolith analog) were collected during a field study in the summer of 2005. The amino acids ( alanine, aspartic acid, glutamic acid, glycine, serine, and valine) chosen for analysis were present in the samples at concentrations of 1 - 70 parts- per- billion. Subcritical water extraction efficiency was examined over the temperature range of 30 - 325 degrees C, at pressures of 17.2 or 20.0 MPa, and for water- sample contact equilibration times of 0 - 30 min. None of the amino acids were extracted in detectable amounts at 30 degrees C ( at 17.2 MPa), suggesting that amino acids are too strongly bound by the soil matrix to be extracted at such a low temperature. Between 150 degrees C and 250 degrees C ( at 17.2 MPa), the extraction efficiencies of glycine, alanine, and valine were observed to increase with increasing water temperature, consistent with higher solubility at higher temperatures, perhaps due to the decreasing dielectric constant of water. Amino acids were not detected in extracts collected at 325 degrees C ( at 20.0 MPa), probably due to amino acid decomposition at this temperature. The optimal subcritical water extraction conditions for these amino acids from Atacama Desert soils were achieved at 200 degrees C, 17.2 MPa, and a water- sample contact equilibration time of 10 min.

Echinococcus granulosus: specificity of amino acid transport systems in protoscoleces.

PubMed

Jeffs, S A; Arme, C

1987-08-01

Protoscoleces of Echinococcus granulosus absorb the L-amino acids proline, methionine, leucine, alanine, serine, phenylalanine, lysine and glutamic acid by a combination of mediated transport and diffusion. All eight amino acids were accumulated against a concentration gradient. Comparison of Kt and Vmax values suggests that a low affinity for a particular compound is compensated for by a relatively larger number of transport sites for that compound. Four systems serve for the transport of the eight substrates studied: 2 for neutral (EgN1, EgN2) and 1 each for acidic (EgA) and basic (EgB) amino acids. All eight amino acids are incorporated into protein to varying degrees and substantial portions of absorbed L-alanine and L-methionine are metabolized into other compounds.

Amino Acid Stability in the Early Oceans

NASA Technical Reports Server (NTRS)

Parker, E. T.; Brinton, K. L.; Burton, A. S.; Glavin, D. P.; Dworkin, J. P.; Bada, J. L.

2015-01-01

It is likely that a variety of amino acids existed in the early oceans of the Earth at the time of the origin and early evolution of life. "Primordial soup", hydrothermal vent, and meteorite based processes could have contributed to such an inventory. Several "protein" amino acids were likely present, however, based on prebiotic synthesis experiments and carbonaceous meteorite studies, non-protein amino acids, which are rare on Earth today, were likely the most abundant. An important uncertainty is the length of time these amino acids could have persisted before their destruction by abiotic and biotic processes. Prior to life, amino acid concentrations in the oceans were likely regulated by circulation through hydro-thermal vents. Today, the entire ocean circulates through vent systems every 10(exp 7) years. On the early Earth, this value was likely smaller due to higher heat flow and thus marine amino acid life-time would have been shorter. After life, amino acids in the oceans could have been assimilated by primitive organisms.

Synthesis and Biological Evaluation of (S)-Amino-2-methyl-4-[(76)Br]bromo-3-(E)-butenoic Acid (BrVAIB) for Brain Tumor Imaging.

PubMed

Burkemper, Jennifer L; Huang, Chaofeng; Li, Aixiao; Yuan, Liya; Rich, Keith; McConathy, Jonathan; Lapi, Suzanne E

2015-11-12

The novel compound, (S)-amino-2-methyl-4-[(76)Br]bromo-3-(E)-butenoic acid (BrVAIB, [(76)Br]5), was characterized against the known system A tracer, IVAIB ([(123)I]8). [(76)Br]5 was prepared in a 51% ± 19% radiochemical yield with high radiochemical purity (≥98%). The biological properties of [(76)Br]5 were compared with those of [(123)I]8. Results showed that [(76)Br]5 undergoes mixed amino acid transport by system A and system L transport, while [(123)I]8 had less uptake by system L. [(76)Br]5 demonstrated higher uptake than [(123)I]8 in DBT tumors 1 h after injection (3.7 ± 0.4% ID/g vs 1.5 ± 0.3% ID/g) and also showed higher uptake vs [(123)I]8 in normal brain. Small animal PET studies with [(76)Br]5 demonstrated good tumor visualization of intracranial DBTs up to 24 h with clearance from normal tissues. These results indicate that [(76)Br]5 is a promising PET tracer for brain tumor imaging and lead compound for a mixed system A and system L transport substrate.

Optical Sensors for Detection of Amino Acids.

PubMed

Pettiwala, Aafrin M; Singh, Prabhat K

2017-11-06

Amino acids are crucially involved in a myriad of biological processes. Any aberrant changes in physiological level of amino acids often manifest in common metabolic disorders, serious neurological conditions and cardiovascular diseases. Thus, devising methods for detection of trace amounts of amino acids becomes highly elemental to their efficient clinical diagnosis. Recently, the domain of developing optical sensors for detection of amino acids has witnessed significant activity which is the focus of the current review article. We undertook a detailed search of the peer-reviewed literature that primarily deals with optical sensors for amino acids and focuses on the use of different type of materials as a sensing platform. Ninety-five papers have been included in the review, majority of which deals with optical sensors. We attempt to systematically classify these contributions based on applications of various chemical and biological scaffolds such as polymers, supramolecular assemblies, nanoparticles, DNA, heparin etc. for the sensing of amino acids. This review identifies that supramolecular assemblies and nanomaterial continue to be commonly used materials to devise sensors for amino acids followed by surfactant assemblies. The broad implications of amino acids in human health and diagnosis have stirred a lot of interest to develop optimized optical detection systems for amino acids in recent years, using different materials based on chemical and biological scaffolds. We have also attempted to highlight the merits and demerits of some of the noteworthy sensor systems to instigate further efforts for constructing amino acids sensor based on unconventional concepts. Copyright© Bentham Science Publishers; For any queries, please email at epub@benthamscience.org.

Effect of amino acids on the eutectic behavior of NaCl solutions studied by DSC.

PubMed

Chen, N J; Morikawa, J; Hashimoto, T

2005-06-01

The effect of a series of amino acids on the eutectic behavior of NaCl solutions at isotonic concentration has been studied by differential scanning calorimetry. The inclusion of different amino acids had different effects on eutectic formation. The amino acids were grouped into four categories based on their effect on eutectic formation: category C were amino acids that had no effect on eutectic formation; category D amino acids inhibited eutectic formation; category T amino acids shifted the melting of the eutectic to a lower temperature; category E amino acids caused the formation of a new eutectic with a melting temperature approximately -5 degrees C. The mechanism of these different effects on eutectic behavior is discussed, based on the chemical structure of the amino acids.

Amino acids in the Tagish Lake Meteorite

NASA Technical Reports Server (NTRS)

Kminek, G.; Botta, O.; Glavin, D. P.; Bada, J. L.

2002-01-01

High-performance liquid chromatography (HPLC) based amino acid analysis of a Tagish Lake meteorite sample recovered 3 months after the meteorite fell to Earth have revealed that the amino acid composition of Tagish Lake is strikingly different from that of the CM and CI carbonaceous chondrites. We found that the Tagish Lake meteorite contains only trace levels of amino acids (total abundance = 880 ppb), which is much lower than the total abundance of amino acids in the CI Orgueil (4100 ppb) and the CM Murchison (16 900 ppb). Because most of the same amino acids found in the Tagish Lake meteorite are also present in the Tagish Lake ice melt water, we conclude that the amino acids detected in the meteorite are terrestrial contamination. We found that the exposure of a sample of Murchison to cold water lead to a substantial reduction over a period of several weeks in the amount of amino acids that are not strongly bound to the meteorite matrix. However, strongly bound amino acids that are extracted by direct HCl hydrolysis are not affected by the leaching process. Thus even if there had been leaching of amino acids from our Tagish Lake meteorite sample during its 3 month residence in Tagish Lake ice and melt water, a Murchison type abundance of endogenous amino acids in the meteorite would have still been readily detectable. The low amino acid content of Tagish Lake indicates that this meteorite originated fiom a different type of parent body than the CM and CI chondrites. The parent body was apparently devoid of the reagents such as aldehyldes/ketones, HCN and ammonia needed for the effective abiotic synthesis of amino acids. Based on reflectance spectral measurements, Tagish Lake has been associated with P- or D-type asteroids. If the Tagish Lake meteorite was indeed derived fiom these types of parent bodies, our understanding of these primitive asteroids needs to be reevaluated with respect to their potential inventory of biologically important organic compounds.

The origin of amino acids in lunar regolith samples

NASA Astrophysics Data System (ADS)

Elsila, Jamie E.; Callahan, Michael P.; Dworkin, Jason P.; Glavin, Daniel P.; McLain, Hannah L.; Noble, Sarah K.; Gibson, Everett K.

2016-01-01

We analyzed the amino acid content of seven lunar regolith samples returned by the Apollo 16 and Apollo 17 missions and stored under NASA curation since collection using ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Consistent with results from initial analyses shortly after collection in the 1970s, we observed amino acids at low concentrations in all of the curated samples, ranging from 0.2 parts-per-billion (ppb) to 42.7 ppb in hot-water extracts and 14.5-651.1 ppb in 6 M HCl acid-vapor-hydrolyzed, hot-water extracts. Amino acids identified in the Apollo soil extracts include glycine, D- and L-alanine, D- and L-aspartic acid, D- and L-glutamic acid, D- and L-serine, L-threonine, and L-valine, all of which had previously been detected in lunar samples, as well as several compounds not previously identified in lunar regoliths: α-aminoisobutyric acid (AIB), D- and L-β-amino-n-butyric acid (β-ABA), DL-α-amino-n-butyric acid, γ-amino-n-butyric acid, β-alanine, and ε-amino-n-caproic acid. We observed an excess of the L enantiomer in most of the detected proteinogenic amino acids, but racemic alanine and racemic β-ABA were present in some samples. We also examined seven samples from Apollo 15, 16, and 17 that had been previously allocated to a non-curation laboratory, as well as two samples of terrestrial dunite from studies of lunar module engine exhaust that had been stored in the same laboratory. The amino acid content of these samples suggested that contamination had occurred during non-curatorial storage. We measured the compound-specific carbon isotopic ratios of glycine, β-alanine, and L-alanine in Apollo regolith sample 70011 and found values of -21‰ to -33‰. These values are consistent with those seen in terrestrial biology and, together with the enantiomeric compositions of the proteinogenic amino acids, suggest that terrestrial biological contamination is a primary source of the

Evaluating the role of acidic, basic, and polar amino acids and dipeptides on a molecular electrocatalyst for H 2 oxidation

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

Boralugodage, Nilusha Priyadarshani; Arachchige, Rajith Jayasingha; Dutta, Arnab

Amino acids and peptides have been shown to have a significant influence on the H2 production and oxidation reactivity of Ni(P R 2N R’ 2) 2, where P R 2N R’ 2 = 1,5-diaza-3,7-diphosphacyclooctane, R is either phenyl (Ph) or cyclohexyl (Cy), and R’ is either an amino acid or peptide. Most recently, the Ni(P Cy 2Naminoacid 2) 2 complexes (CyAA) have shown enhanced H 2 oxidation rates, water solubility, and in the case of arginine (CyArg) and phenylalanine (CyPhe), electrocatalytic reversibility. Both the backbone –COOH and side chain interactions were shown to be critical to catalytic performance. Here wemore » further investigate the roles of the outer coordination sphere by evaluating amino acids with acidic, basic, and hydrophilic side chains, as well as dipeptides which combine multiple successful features from previous complexes. Six new complexes were prepared, three containing single amino acids: aspartic acid (CyAsp), lysine (CyLys), and serine (CySer) and three containing dipeptides: glycine-phenylalanine (Cy(GlyPhe)), phenylalanine-glycine (Cy(PheGly)), and aspartic acid-phenylananine (Cy(AspPhe)). The resulting catalytic performance demonstrates that complexes need both interactions between side chain and –COOH groups for fast, efficient catalysis. The fastest of all of the catalysts, Cy(AspPhe), had both of these features, while the other dipeptide complexes with an amide replacing the -COOH were both slower; however, the amide group was demonstrated to participate in the proton pathway when side chain interactions are present to position it. Both the hydrophilic and basic side chains, notably lacking in side chain interactions, significantly increased the overpotential, with only modest increases in TOF. Of all of the complexes, only CyAsp was reversible at room temperature, and only in water, the first of these complexes to demonstrate room temperature reversibility in water. These results continue to provide and solidify design rules for

Nature's starships. I. Observed abundances and relative frequencies of amino acids in meteorites

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

Cobb, Alyssa K.; Pudritz, Ralph E., E-mail: cobbak@mcmaster.ca, E-mail: pudritz@physics.mcmaster.ca

The class of meteorites called carbonaceous chondrites are examples of material from the solar system which have been relatively unchanged from the time of their initial formation. These meteorites have been classified according to the temperatures and physical conditions of their parent planetesimals. We collate available data on amino acid abundance in these meteorites and plot the concentrations of different amino acids for each meteorite within various meteorite subclasses. We plot average concentrations for various amino acids across meteorites separated by subclass and petrologic type. We see a predominance in the abundance and variety of amino acids in CM2 andmore » CR2 meteorites. The range in temperature corresponding to these subclasses indicates high degrees of aqueous alteration, suggesting aqueous synthesis of amino acids. Within the CM2 and CR2 subclasses, we identify trends in relative frequencies of amino acids to investigate how common amino acids are as a function of their chemical complexity. These two trends (total abundance and relative frequencies) can be used to constrain formation parameters of amino acids within planetesimals. Our organization of the data supports an onion shell model for the temperature structure of planetesimals. The least altered meteorites (type 3) and their amino acids originated near cooler surface regions. The most active amino acid synthesis likely took place at intermediate depths (type 2). The most altered materials (type 1) originated furthest toward parent body cores. This region is likely too hot to either favor amino acid synthesis or for amino acids to be retained after synthesis.« less

Amino acids in the Martian meteorite Nakhla

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Bada, J. L.; Brinton, K. L.; McDonald, G. D.

1999-01-01

A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, beta-alanine, and gamma-amino-n-butyric acid (gamma-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

Amino acids in the Martian meteorite Nakhla.

PubMed

Glavin, D P; Bada, J L; Brinton, K L; McDonald, G D

1999-08-03

A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, beta-alanine, and gamma-amino-n-butyric acid (gamma-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

Amino acids in the Martian meteorite Nakhla

PubMed Central

Glavin, Daniel P.; Bada, Jeffrey L.; Brinton, Karen L. F.; McDonald, Gene D.

1999-01-01

A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, β-alanine, and γ-amino-n-butyric acid (γ-ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the d/l ratios (values range from <0.1 to 0.5), is similar to what is found in bacterially degraded organic matter. The amino acids in Nakhla appear to be derived from terrestrial organic matter that infiltrated the meteorite soon after its fall to Earth, although it is possible that some of the amino acids are endogenous to the meteorite. The rapid amino acid contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth. PMID:10430856

Cometary Amino Acids from the STARDUST Mission

NASA Technical Reports Server (NTRS)

Cook, Jamie Elsila

2009-01-01

NASA's Stardust spacecraft returned samples from comet 81 P/WiId 2 to Earth in January 2006. Examinations of the organic compounds in cometary samples can reveal information about the prebiotic organic inventory present on the early Earth and within the early Solar System, which may have contributed to the origin of life. Preliminary studies of Stardust material revealed the presence of a suite of organic compounds including several amines and amino acids, but the origin of these compounds (cometary vs. terrestrial contamination) could not be identified. We have recently measured the carbon isotopic ratios of these amino acids to determine their origin, leading to the first detection of a cometary amino acid.

Searching for Extraterrestrial Amino Acids in a Contaminated Meteorite: Amino Acid Analyses of the Canakkale L6 Chondrite

NASA Technical Reports Server (NTRS)

Burton, A. S.; Elsila, J. E.; Glavin, D. P.; Dworkin, J. P.; Ornek, C. Y.; Esenoglu, H. H.; Unsalan, O.; Ozturk, B.

2016-01-01

Amino acids can serve as important markers of cosmochemistry, as their abundances and isomeric and isotopic compositions have been found to vary predictably with changes in parent body chemistry and alteration processes. Amino acids are also of astrobiological interest because they are essential for life on Earth. Analyses of a range of meteorites, including all groups of carbonaceous chondrites, along with H, R, and LL chondrites, ureilites, and a martian shergottite, have revealed that amino acids of plausible extraterrestrial origin can be formed in and persist after a wide range of parent body conditions. However, amino acid analyses of L6 chondrites to date have not provided evidence for indigenous amino acids. In the present study, we performed amino acid analysis on larger samples of a different L6 chondite, Canakkale, to determine whether or not trace levels of indigenous amino acids could be found. The Canakkale meteor was an observed fall in late July, 1964, near Canakkale, Turkey. The meteorite samples (1.36 and 1.09 g) analyzed in this study were allocated by C. Y. Ornek, along with a soil sample (1.5 g) collected near the Canakkale recovery site.

Amino acids as possible alternative nitrogen source for growth of Euglena gracilis Z in life support systems

NASA Astrophysics Data System (ADS)

Richter, P. R.; Liu, Y.; An, Y.; Li, X.; Nasir, A.; Strauch, S. M.; Becker, I.; Krüger, J.; Schuster, M.; Ntefidou, M.; Daiker, V.; Haag, F. W. M.; Aiach, A.; Lebert, M.

2015-01-01

In recent times Euglena gracilis Z was employed as primary producer in closed environmental life-support system (CELSS), e.g. in space research. The photosynthetic unicellular flagellate is not capable of utilizing nitrate, nitrite, and urea as nitrogen source. Therefore, ammonium is supplied as an N-source in the lab (provided as diammonium-dihydrogenphosphate, (NH4)2HPO4) to E. gracilis cultures. While nitrate exerts low toxicity to organisms, ammonium is harmful for many aquatic organisms especially, at high pH-values, which causes the ionic NH+4 (low toxicity) to be partially transformed into the highly toxic ammonia, NH3. In earlier reports, Euglena gracilis was described to grow with various amino acids as sole N-source. Our aim was to investigate alternatives for (NH4)2HPO4 as N-source with lower toxicity for organisms co-cultivated with Euglena in a CELSS. The growth kinetics of Euglena gracilis cultures was determined in the presence of different amino acids (glycine, glutamine, glutamic acid, leucine, and threonine). In addition, uptake of those amino acids by the cells was measured. Cell growth in the presence of glycine and glutamine was quite comparable to the growth in (NH4)2HPO4 containing cultures while a delay in growth was observed in the presence of leucine and threonine. Unlike, aforementioned amino acids glutamate consumption was very poor. Cell density and glutamate concentration were almost unaltered throughout the experiment and the culture reached the stationary phase within 8 days. The data are compared with earlier studies in which utilization of amino acids in Euglena gracilis was investigated. All tested amino acids (glutamate with limitations) were found to have the potential of being an alternative N-source for Euglena gracilis. Hence, these amino acids can be used as a non-toxic surrogate for (NH4)2HPO4.

Sites that Can Produce Left-handed Amino Acids in the Supernova Neutrino Amino Acid Processing Model

NASA Astrophysics Data System (ADS)

Boyd, Richard N.; Famiano, Michael A.; Onaka, Takashi; Kajino, Toshitaka

2018-03-01

The Supernova Neutrino Amino Acid Processing model, which uses electron anti-neutrinos and the magnetic field from a source object such as a supernova to selectively destroy one amino acid chirality, is studied for possible sites that would produce meteoroids with partially left-handed amino acids. Several sites appear to provide the requisite magnetic field intensities and electron anti-neutrino fluxes. These results have obvious implications for the origin of life on Earth.

Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions

NASA Astrophysics Data System (ADS)

Tarasevych, Arkadii V.; Vives, Thomas; Snytnikov, Valeriy N.; Guillemin, Jean-Claude

2017-09-01

The heating above 400 °C of serine, cysteine, selenocysteine and threonine leads to a complete decomposition of the amino acids and to the formation in low yields of alanine for the three formers and of 2-aminobutyric acid for the latter. At higher temperature, this amino acid is observed only when sublimable α-alkyl-α-amino acids are present, and with an enantiomeric excess dependent on several parameters. Enantiopure or enantioenriched Ser, Cys, Sel or Thr is not able to transmit its enantiomeric excess to the amino acid formed during its decomposition. The presence during the sublimation-decomposition of enantioenriched valine or isoleucine leads to the enantioenrichment of all sublimable amino acids independently of the presence of many decomposition products coming from the unstable derivative. All these studies give information on a potentially prebiotic key-reaction of abiotic transformations between α-amino acids and their evolution to homochirality.

d-Amino acids in molecular evolution in space - Absolute asymmetric photolysis and synthesis of amino acids by circularly polarized light.

PubMed

Sugahara, Haruna; Meinert, Cornelia; Nahon, Laurent; Jones, Nykola C; Hoffmann, Søren V; Hamase, Kenji; Takano, Yoshinori; Meierhenrich, Uwe J

2018-07-01

Living organisms on the Earth almost exclusively use l-amino acids for the molecular architecture of proteins. The biological occurrence of d-amino acids is rare, although their functions in various organisms are being gradually understood. A possible explanation for the origin of biomolecular homochirality is the delivery of enantioenriched molecules via extraterrestrial bodies, such as asteroids and comets on early Earth. For the asymmetric formation of amino acids and their precursor molecules in interstellar environments, the interaction with circularly polarized photons is considered to have played a potential role in causing chiral asymmetry. In this review, we summarize recent progress in the investigation of chirality transfer from chiral photons to amino acids involving the two major processes of asymmetric photolysis and asymmetric synthesis. We will discuss analytical data on cometary and meteoritic amino acids and their potential impact delivery to the early Earth. The ongoing and future ambitious space missions, Hayabusa2, OSIRIS-REx, ExoMars 2020, and MMX, are scheduled to provide new insights into the chirality of extraterrestrial organic molecules and their potential relation to the terrestrial homochirality. This article is part of a Special Issue entitled: d-Amino acids: biology in the mirror, edited by Dr. Loredano Pollegioni, Dr. Jean-Pierre Mothet and Dr. Molla Gianluca. Copyright © 2018 Elsevier B.V. All rights reserved.

Molecular docking, vibrational, structural, electronic and optical studies of {4 - (2, 6) dichlorophenyl amino 2 - methylidene 4 - oxobutanoic acid and 4- (2, 5)} dichlorophenyl amino 2 - methylidene 4 - oxobutanoic acid - A comparative study

NASA Astrophysics Data System (ADS)

Vanasundari, K.; Balachandran, V.; Kavimani, M.; Narayana, B.

2018-03-01

Spectroscopic and structural investigations of 4 - [(2, 6 - dichlorophenyl) amino] 2 -methylidene 4 - oxobutanoic acid (6DAMB) and 4-[(2, 5- dichlorophenyl) amino] 2 - methylidene 4 - oxobutanoic acid (5DAMB) are presented by using experimental (FT-IR and FT-Raman) spectra and theoretical (DFT approach) calculations. Seventy-two characteristic vibrational bands of the title compounds were assigned and compared with available experimental data. Stability of the molecule arising from hyper-conjugative interactions and charge delocalization was analyzed using natural bond orbital (NBO) analysis. Several descriptors determined from the energies of frontier molecular orbital (HOMO and LUMO) were applied to describe the reactivity of the title compound. The dipole moment and first hyperpolarizabilities of the studied compounds indicate that the compound is a good candidate of nonlinear optical materials. Theoretical Ultraviolet-Visible spectra of title compounds have been analyzed using the TD-DFT method. The noncovalent interactions like hydrogen bonding and Van der Waals interaction were identified from the molecular geometry and electron localization function. These interactions in molecules have been studied by using reduced density gradient (RDG) and graphed by Multiwfn. Auto-dock studies reveal that butanoic acid derivatives play a vital role in bonding and results draw us to the concluded that both compounds inhibit Placenta growth factor (PIGF-1) and that have good biological activities. This study may also provide further investigation on butanoic acid derivatives for pharmacological importance.

Biopolymers Containing Unnatural Amino Acids

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

Schultz, Peter

Although the main chain structure of polymers has a profound effect on their materials properties, the side groups can also have dramatic effects on their properties including conductivity, liquid crystallinity, hydrophobicity, elasticity and biodegradability. Unfortunately control over the side chain structure of polymers remains a challenge – it is difficult to control the sequence of chain elongation when mixtures of monomers are polymerized, and postpolymerization side chain modification is made difficult by polymer effects on side chain reactivity. In contrast, the mRNA templated synthesis of polypeptides on the ribosome affords absolute control over the primary sequence of the twenty aminomore » acid monomers. Moreover, the length of the biopolymer is precisely controlled as are sites of crosslinking. However, whereas synthetic polymers can be synthesized from monomers with a wide range of chemically defined structures, ribosomal biosynthesis is largely limited to the 20 canonical amino acids. For many applications in material sciences, additional building blocks would be desirable, for example, amino acids containing metallocene, photoactive, and halogenated side chains. To overcome this natural constraint we have developed a method that allows unnatural amino acids, beyond the common twenty, to be genetically encoded in response to nonsense or frameshift codons in bacteria, yeast and mammalian cells with high fidelity and good yields. Here we have developed methods that allow identical or distinct noncanonical amino acids to be incorporated at multiple sites in a polypeptide chain, potentially leading to a new class of templated biopolymers. We have also developed improved methods for genetically encoding unnatural amino acids. In addition, we have genetically encoded new amino acids with novel physical and chemical properties that allow selective modification of proteins with synthetic agents. Finally, we have evolved new metal-ion binding sites in

Synthesis of Amino Acid Precursors with Organic Solids in Planetesimals with Liquid Water

NASA Technical Reports Server (NTRS)

Kebukawa, Y; Misawa, S.; Matsukuma, J.; Chan, Q. H. S.; Kobayashi, J.; Tachibana, S.; Zolensky, M. E.

2017-01-01

Amino acids are important ingredients of life that would have been delivered to Earth by extraterrestrial sources, e.g., comets and meteorites. Amino acids are found in aqueously altered carbonaceous chondrites in good part in the form of precursors that release amino acids after acid hydrolysis. Meanwhile, most of the organic carbon (greater than 70 weight %) in carbonaceous chondrites exists in the form of solvent insoluble organic matter (IOM) with complex macromolecular structures. Complex macromolecular organic matter can be produced by either photolysis of interstellar ices or aqueous chemistry in planetesimals. We focused on the synthesis of amino acids during aqueous alteration, and demonstrated one-pot synthesis of a complex suite of amino acids simultaneously with IOM via hydrothermal experiments simulating the aqueous processing

An In Silico study of TiO2 nanoparticles interaction with twenty standard amino acids in aqueous solution

NASA Astrophysics Data System (ADS)

Liu, Shengtang; Meng, Xuan-Yu; Perez-Aguilar, Jose Manuel; Zhou, Ruhong

2016-11-01

Titanium dioxide (TiO2) is probably one of the most widely used nanomaterials, and its extensive exposure may result in potentially adverse biological effects. Yet, the underlying mechanisms of interaction involving TiO2 NPs and macromolecules, e.g., proteins, are still not well understood. Here, we perform all-atom molecular dynamics simulations to investigate the interactions between TiO2 NPs and the twenty standard amino acids in aqueous solution exploiting a newly developed TiO2 force field. We found that charged amino acids play a dominant role during the process of binding to the TiO2 surface, with both basic and acidic residues overwhelmingly preferred over the non-charged counterparts. By calculating the Potential Mean Force, we showed that Arg is prone to direct binding onto the NP surface, while Lys needs to overcome a ~2 kT free energy barrier. On the other hand, acidic residues tend to form “water bridges” between their sidechains and TiO2 surface, thus displaying an indirect binding. Moreover, the overall preferred positions and configurations of different residues are highly dependent on properties of the first and second solvation water. These molecular insights learned from this work might help with a better understanding of the interactions between biomolecules and nanomaterials.

Urinary and plasma organic acids and amino acids in chronic fatigue syndrome.

PubMed

Jones, Mark G; Cooper, Elizabeth; Amjad, Saira; Goodwin, C Stewart; Barron, Jeffrey L; Chalmers, Ronald A

2005-11-01

Previous work by others have suggested the occurrence of one or more chemical or metabolic 'markers' for ME/CFS including specific amino acids and organic acids and a number of unidentified compounds (CFSUM1, CFSUM2). We have shown elsewhere that CFSUM1 is partially derivatised pyroglutamic acid and CFSUM2 partially derivatised serine and have suggested and demonstrated that the analytical methods used were unsuitable to identify or to accurately quantify urinary metabolites. We have now made a detailed analysis of plasma and urinary amino acids and of urinary organic acids from patients with ME/CFS and from three control groups. Fasting blood plasma and timed urine samples were obtained from 31 patients with CFS, 31 age and sex-matched healthy controls, 15 patients with depression and 22 patients with rheumatoid arthritis. Plasma and urinary amino acids and urinary organic acids were determined using established and validated methods and data compared by statistical analysis. None of the previously reported abnormalities in urinary amino acids or of organic acids could be confirmed. Results however provide some evidence in patients with ME/CFS for underlying inflammatory disease and for reduced intramuscular collagen with a lowered threshold for muscle micro-injury. These factors in combination may provide a basis for the fatigue and muscle pain that are the major symptoms in these patients.

Genetics of Amino Acid Taste and Appetite.

PubMed

Bachmanov, Alexander A; Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Reed, Danielle R; Tordoff, Michael G; Beauchamp, Gary K

2016-07-01

The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. © 2016 American Society for Nutrition.

Protein and amino acid nutrition

USDA-ARS?s Scientific Manuscript database

Dairy cow protein and amino acid nutrition have a significant role in sustainable dairying. Protein, amino acids, and nitrogen are inextricably linked through effects in the rumen, metabolism of the cow, and environmental nutrient management. Feeding systems have been making progress toward emphasiz...

78 FR 42530 - Prospective Grant of an Exclusive License: Human Papillomavirus 16 E2 and E6 Peptides for...

Federal Register 2010, 2011, 2012, 2013, 2014

2013-07-16

... E2. These epitopes generated from amino acid positions 69-77 (ALQAIELQL) and 138-147 (YICEEASVTV... KLPDLCTELX 2 ;, wherein X 2 and X 1 are peptides of 0-11 amino acids in length comprising contiguous HPV 18 E6 amino acid sequences) protein that comprise class I restricted T cell epitopes and methods of...

Identification of Critical Amino Acids in the IgE Epitopes of Ric c 1 and Ric c 3 and the Application of Glutamic Acid as an IgE Blocker

PubMed Central

Deus-de-Oliveira, Natalia; Felix, Shayany P.; Carrielo-Gama, Camila; Fernandes, Keysson V.; DaMatta, Renato Augusto; Machado, Olga L. T.

2011-01-01

Background The allergenicity of Ricinus communis L. (castor bean, Euphorbiaceae) is associated with components of its seeds and pollen. Castor bean allergy has been described not only in laboratory workers, but also in personnel working in oil processing mills, fertilizer retail, the upholstery industry and other industrial fields. In the present study, we describe the critical amino acids in the IgE-binding epitopes in Ric c 1 and Ric c 3, two major allergens of R. communis. In addition, we also investigate the cross-reactivity between castor bean and some air and food allergen extracts commonly used in allergy diagnosis. Methodology/Principal Findings The IgE reactivity of human sera from atopic patients was screened by immune-dot blot against castor bean allergens. Allergenic activity was evaluated in vitro using a rat mast cell activation assay and by ELISA. Cross-reactivity was observed between castor bean allergens and extracts from shrimp, fish, gluten, wheat, soybean, peanut, corn, house dust, tobacco and airborne fungal allergens. We observed that treatment of rat and human sera (from atopic patients) with glutamic acid reduced the IgE-epitope interaction. Conclusions/Significance The identification of glutamic acid residues with critical roles in IgE-binding to Ric c 3 and Ric c 1 support the potential use of free amino acids in allergy treatment. PMID:21738671

Evolution of the biosynthesis of the branched-chain amino acids

NASA Technical Reports Server (NTRS)

Keefe, Anthony D.; Lazcano, Antonio; Miller, Stanley L.

1995-01-01

The origins of the biosynthetic pathways for the branched-chain amino acids cannot be understood in terms of the backwards development of the present acetolactate pathway because it contains unstable intermediates. We propose that the first biosynthesis of the branched-chain amino acids was by the reductive carboxylation of short branched chain fatty acids giving keto acids which were then transaminated. Similar reaction sequences mediated by nonspecific enzymes would produce serine and threomine from the abundant prebiotic compounds glycolic and lactic acids. The aromatic amino acids may also have first been synthesized in this way, e.g. tryptophan from indole acetic acid. The next step would have been the biosynthesis of leucine from alpha-ketoisovalerc acid. The acetolactate pathway developed subsequently. The first version of the Krebs cycle, which was used for amino acid biosynthesis, would have been assembled by making use fo the reductive carboxylation and leucine biosynthesis enzymes, and completed with the development of a single new enzyme, succinate dehydrogenase. This evolutionary scheme suggests that there may be limitations to inferring the origins of metabolism by a simple back extrapolation of current pathways.

Synthesis and biological activity of amino acid conjugates of abscisic acid.

PubMed

Todoroki, Yasushi; Narita, Kenta; Muramatsu, Taku; Shimomura, Hajime; Ohnishi, Toshiyuki; Mizutani, Masaharu; Ueno, Kotomi; Hirai, Nobuhiro

2011-03-01

We prepared 19 amino acid conjugates of the plant hormone abscisic acid (ABA) and investigated their biological activity, enzymatic hydrolysis by a recombinant Arabidopsis amidohydrolases GST-ILR1 and GST-IAR3, and metabolic fate in rice seedlings. Different sets of ABA-amino acids induced ABA-like responses in different plants. Some ABA-amino acids, including some that were active in bioassays, were hydrolyzed by recombinant Arabidopsis GST-IAR3, although GST-ILR1 did not show hydrolysis activity for any of the ABA-amino acids. ABA-L-Ala, which was active in all the bioassays, an Arabidopsis seed germination, spinach seed germination, and rice seedling elongation assays, except in a lettuce seed germination assay and was hydrolyzed by GST-IAR3, was hydrolyzed to free ABA in rice seedlings. These findings suggest that some plant amidohydrolases hydrolyze some ABA-amino acid conjugates. Because our study indicates the possibility that different plants have hydrolyzing activity toward different ABA-amino acids, an ABA-amino acid may function as a species-selective pro-hormone of ABA. Copyright © 2011 Elsevier Ltd. All rights reserved.

Amino Acid Contents of Meteorite Mineral Separates

NASA Technical Reports Server (NTRS)

Berger, E. L.; Burton, A. S; Locke, D.

2017-01-01

Indigenous amino acids have been found indigenous all 8 carbonaceous chondrite groups. However, the abundances, structural, enantiomeric and isotopic compositions of amino acids differ significantly among meteorites of different groups and petrologic types. This suggests that parent-body conditions (thermal or aqueous alteration), mineralogy, and the preservation of amino acids are linked. Previously, elucidating specific relationships between amino acids and mineralogy was not possible because the samples analyzed for amino acids were much larger than the scale at which petrologic heterogeneity is observed (sub mm-scale differences corresponding to sub-mg samples). Recent advances in amino acid measurements and application of techniques such as high resolution X-ray diffraction (HR-XRD) and scanning electron microscopy (SEM) with energy dispersive spectroscopy (EDS) for mineralogical characterizations allow us to perform coordinated analyses on the scale at which mineral heterogeneity is observed.

Amino acids of the Murchison meteorite. II - Five carbon acyclic primary beta-, gamma-, and delta-amino alkanoic acids

NASA Technical Reports Server (NTRS)

Cronin, J. R.; Pizzarello, S.; Yuen, G. U.

1985-01-01

The five-carbon acyclic primary beta, gamma, and delta amino alkanoic acids of the Murchison meteorite are studied using gas chromatography-mass spectrometry and ion exchange chromatography. The chromatograms reveal that alpha is the most abundant monoamino alkanoic acid followed by gamma and beta, and an exponential increase in the amount of amino acid is observed as the carbon number increases in the homologous series. The influence of frictional heating, spontaneous thermal decomposition, and radiation of the synthesis of amino acids is examined. The data obtained support an amino acid synthesis process involving random combination of single-carbon precursors.

Effects of Long-Term Protein Restriction on Meat Quality, Muscle Amino Acids, and Amino Acid Transporters in Pigs.

PubMed

Yin, Jie; Li, Yuying; Zhu, Xiaotong; Han, Hui; Ren, Wenkai; Chen, Shuai; Bin, Peng; Liu, Gang; Huang, Xingguo; Fang, Rejun; Wang, Bin; Wang, Kai; Sun, Liping; Li, Tiejun; Yin, Yulong

2017-10-25

This study aimed to investigate the long-term effects of protein restriction from piglets to finishing pigs for 16 weeks on meat quality, muscle amino acids, and amino acid transporters. Thirty-nine piglets were randomly divided into three groups: a control (20-18-16% crude protein, CP) and two protein restricted groups (17-15-13% CP and 14-12-10% CP). The results showed that severe protein restriction (14-12-10% CP) inhibited feed intake and body weight, while moderate protein restriction (17-15-13% CP) had little effect on growth performance in pigs. Meat quality (i.e., pH, color traits, marbling, water-holding capacity, and shearing force) were tested, and the results exhibited that 14-12-10% CP treatment markedly improved muscle marbling score and increased yellowness (b*). pH value (45 min) was significantly higher in 17-15-13% CP group than that in other groups. In addition, protein restriction reduced muscle histone, arginine, valine, and isoleucine abundances and enhanced glycine and lysine concentrations compared with the control group, while the RT-PCR results showed that protein restriction downregulated amino acids transporters. Mechanistic target of rapamycin (mTOR) signaling pathway was inactivated in the moderate protein restricted group (17-15-13% CP), while severe protein restriction with dietary 14-12-10% CP markedly enhanced mTOR phosphorylation. In conclusion, long-term protein restriction affected meat quality and muscle amino acid metabolism in pigs, which might be associated with mTOR signaling pathway.

The impacts of temperature, alcoholic degree and amino acids content on biogenic amines and their precursor amino acids content in red wine.

PubMed

Lorenzo, C; Bordiga, M; Pérez-Álvarez, E P; Travaglia, F; Arlorio, M; Salinas, M R; Coïsson, J D; Garde-Cerdán, T

2017-09-01

The aim was to study how factors such as temperature, alcoholic degree, and amino acids supplementation are able to influence the content of tyramine, histamine, 2-phenylethylamine, tryptamine and their precursor amino acids in winemaking process. Biogenic amines and amino acids were quantified at the beginning, middle and end of alcoholic fermentation, and at the end of malolactic fermentation. In general, samples produced with amino acid supplementation did not show the highest concentrations of biogenic amines, except for histamine, which content increased with the addition of the four amino acids. The synthesis of tyramine was mainly affected by the temperature and alcoholic degree, the formation of phenylethylamine was largely influenced by alcoholic degree, and tryptamine synthesis principally depended on temperature. Interestingly, there was interaction between these three factors for the biogenic amines studied. In conclusion, winemaking conditions should be established depending on the biogenic amine which synthesis is required to be controlled. Copyright © 2017 Elsevier Ltd. All rights reserved.

Discovery and History of Amino Acid Fermentation.

PubMed

Hashimoto, Shin-Ichi

There has been a strong demand in Japan and East Asia for L-glutamic acid as a seasoning since monosodium glutamate was found to present umami taste in 1907. The discovery of glutamate fermentation by Corynebacterium glutamicum in 1956 enabled abundant and low-cost production of the amino acid, creating a large market. The discovery also prompted researchers to develop fermentative production processes for other L-amino acids, such as lysine. Currently, the amino acid fermentation industry is so huge that more than 5 million metric tons of amino acids are manufactured annually all over the world, and this number continues to grow. Research on amino acid fermentation fostered the notion and skills of metabolic engineering which has been applied for the production of other compounds from renewable resources. The discovery of glutamate fermentation has had revolutionary impacts on both the industry and science. In this chapter, the history and development of glutamate fermentation, including the very early stage of fermentation of other amino acids, are reviewed.

Stereoselective synthesis of functionalized cyclic amino acid derivatives via a [2,3]-Stevens rearrangement and ring-closing metathesis.

PubMed

Nash, Aaron; Soheili, Arash; Tambar, Uttam K

2013-09-20

Unnatural cyclic amino acids are valuable tools in biomedical research and drug discovery. A two-step stereoselective strategy for converting simple glycine-derived aminoesters into unnatural cyclic amino acid derivatives has been developed. The process includes a palladium-catalyzed tandem allylic amination/[2,3]-Stevens rearrangement followed by a ruthenium-catalyzed ring-closing metathesis. The [2,3]-rearrangement proceeds with high diastereoselectivity through an exo transition state. Oppolzer's chiral auxiliary was utilized to access an enantiopure cyclic amino acid by this approach, which will enable future biological applications.

Research for amino acids in lunar samples.

NASA Technical Reports Server (NTRS)

Gehrke, C. W.; Zumwalt, R. W.; Kuo, K.; Rash, J. J.; Aue , W. A.; Stalling, D. L.; Kvenvolden, K. A.; Ponnamperuma, C.

1972-01-01

The study was primarily directed toward the examination of Apollo 14 lunar fines for indigenous amino acids or materials which could be converted to amino acids on hydrolysis with 6 N hydrochloric acid. Initial experiments were conducted to confirm the integrity of the derivatization reactions and reagents, and to optimize the gas-liquid chromatographic (GLC) instrumental and chromatographic system for the separation and flame ionization detection of the amino acid derivatives. In studies on the recovery of amino acids added to lunar fines, low recoveries were obtained when 10 ng of each amino acid were added to 50 mg of virgin fines, but the subsequent addition of 50 ng of each to the previously extracted sample resulted in much higher recoveries.

Amino acids in the Yamato carbonaceous chrondrite from Antarctica

NASA Technical Reports Server (NTRS)

Shimoyama, A.; Ponnamperuma, C.; Yanai, K.

1979-01-01

Evidence for the presence of amino acids of extraterrestrial origin in the Antarctic Yamato carbonaceous chrondrite is presented. Hydrolyzed and nonhydrolyzed water-extracted amino acid samples from exterior, middle and interior portions of the meteorite were analyzed by an amino acid analyzer and by gas chromatography of N-TFA-isopropyl amino acid derivatives. Nine protein and six nonprotein amino acids were detected in the meteorite at abundances between 34 and less than one nmole/g, with equal amounts in interior and exterior portions. Nearly equal abundances of the D and L enantiomers of alanine, aspartic acid and glutamic acid were found, indicating the abiotic, therefore extraterrestrial, origin of the amino acids. The Antarctic environment and the uniformity of protein amino acid abundances are discussed as evidence against the racemization of terrestrially acquired amino acids, and similarities between Yamato amino acid compositions and the amino acid compositions of the Murchison and Murray type II carbonaceous chrondrites are indicated.

Increased ubiquitination and reduced plasma membrane trafficking of placental amino acid transporter SNAT-2 in human IUGR

PubMed Central

Rosario, Fredrick J.; Shehab, Majida Abu; Powell, Theresa L.; Gupta, Madhulika B.; Jansson, Thomas

2015-01-01

Placental amino acid transport is decreased in intrauterine growth restriction (IUGR); however, the underlying mechanisms remain largely unknown. We have shown that mechanistic target of rapamycin (mTOR) signalling regulates system A amino acid transport by modulating the ubiquitination and plasma membrane trafficking of sodium-coupled neutral amino acid transporter 2 (SNAT-2) in cultured primary human trophoblast cells. We hypothesize that IUGR is associated with (1) inhibition of placental mTORC1 and mTORC2 signalling pathways, (2) increased amino acid transporter ubiquitination in placental homogenates and (3) decreased protein expression of SNAT-2 in the syncytiotrophoblast microvillous plasma membrane (MVM). To test this hypothesis, we collected placental tissue and isolated MVM from women with pregnancies complicated by IUGR (n=25) and gestational age-matched women with appropriately grown control infants (n=19, birth weights between the twenty-fifth to seventy-fifth percentiles). The activity of mTORC1 and mTORC2 was decreased whereas the protein expression of the ubiquitin ligase NEDD4-2 (neural precursor cell expressed developmentally down-regulated protein 4-2; +72%, P<0.0001) and the ubiquitination of SNAT-2 (+180%, P<0.05) were increased in homogenates of IUGR placentas. Furthermore, IUGR was associated with decreased system A amino acid transport activity (–72%, P<0.0001) and SNAT-1 (–42%, P<0.05) and SNAT-2 (–31%, P<0.05) protein expression in MVM. In summary, these findings are consistent with the possibility that decreased placental mTOR activity causes down-regulation of placental system A activity by shifting SNAT-2 trafficking towards proteasomal degradation, thereby contributing to decreased fetal amino acid availability and restricted fetal growth in IUGR. PMID:26374858

Relation between chemotaxis and consumption of amino acids in bacteria

PubMed Central

Yang, Yiling; M. Pollard, Abiola; Höfler, Carolin; Poschet, Gernot; Wirtz, Markus; Hell, Rüdiger

2015-01-01

Summary Chemotaxis enables bacteria to navigate chemical gradients in their environment, accumulating toward high concentrations of attractants and avoiding high concentrations of repellents. Although finding nutrients is likely to be an important function of bacterial chemotaxis, not all characterized attractants are nutrients. Moreover, even for potential nutrients, the exact relation between the metabolic value of chemicals and their efficiency as chemoattractants has not been systematically explored. Here we compare the chemotactic response of amino acids with their use by bacteria for two well‐established models of chemotactic behavior, E scherichia coli and B acillus subtilis. We demonstrate that in E . coli chemotaxis toward amino acids indeed strongly correlates with their utilization. However, no such correlation is observed for B . subtilis, suggesting that in this case, the amino acids are not followed because of their nutritional value but rather as environmental cues. PMID:25807888

An HPLC method for the determination of selected amino acids in human embryo culture medium.

PubMed

Drábková, Petra; Andrlová, Lenka; Kanďár, Roman

2017-02-01

A method for the determination of selected amino acids in culture medium using HPLC with fluorescence detection is described. Twenty hours after intra-cytoplasmic sperm injection, one randomly selected zygote was transferred to the culture medium. After incubation (72 h after fertilization), the culture medium in which the embryo was incubated and blank medium was immediately stored at -80°C. Filtered medium samples were derivatized with ortho-phthalaldehyde (naphthalene-2,3-dicarboxaldehyde), forming highly fluorescent amino acids derivatives. Reverse-phase columns (LichroCART, Purospher STAR RP 18e or Ascentis Express C 18 ) were used for the separation. The derivatives were analyzed by gradient elution with a mobile phase containing ethanol and sodium dihydrogen phosphate. The analytical performance of this method is satisfactory for all amino acids; the intra-assay coefficients of variation were <10% and quantitative recoveries were between 95.5 and 104.4%. Changes in the levels of selected amino acids before and after human embryo cultivation were observed. After embryo incubation, the levels of all amino acids in the medium were increased, apart from aspartate and asparagine. After the cultivation of some embryos, amino acids which were not part of the medium were detected. Low amino acids turnover was observed in some embryos. Copyright © 2016 John Wiley & Sons, Ltd.

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.

Reaction of 3-Amino-1,2,4-Triazole with Diethyl Phosphite and Triethyl Orthoformate: Acid-Base Properties and Antiosteoporotic Activities of the Products.

PubMed

Miszczyk, Patrycja; Wieczorek, Dorota; Gałęzowska, Joanna; Dziuk, Błażej; Wietrzyk, Joanna; Chmielewska, Ewa

2017-02-08

The reaction of diethyl phosphite with triethyl orthoformate and a primary amine followed by hydrolysis is presented, and the reaction was suitable for the preparation of (aminomethylene)bisphosphonates. 3-Amino-1,2,4-triazole was chosen as an interesting substrate for this reaction because it possesses multiple groups that can serve as the amino component in the reaction-namely, the side-chain and triazole amines. This substrate readily forms 1,2,4-triazolyl-3-yl-aminomethylenebisphosphonic acid (compound 1 ) as a major product, along with N -ethylated bisphosphonates as side products. The in vitro antiproliferative effects of the synthesized aminomethylenebisphosphonic acids against J774E macrophages were determined. These compounds exhibit similar activity to zoledronic acid and higher activity than incadronic acid.

Ultrasound-assisted extraction of amino acids from grapes.

PubMed

Carrera, Ceferino; Ruiz-Rodríguez, Ana; Palma, Miguel; Barroso, Carmelo G

2015-01-01

Recent cultivar techniques on vineyards can have a marked influence on the final nitrogen content of grapes, specifically individual amino acid contents. Furthermore, individual amino acid contents in grapes are related to the final aromatic composition of wines. A new ultrasound-assisted method for the extraction of amino acids from grapes has been developed. Several extraction variables, including solvent (water/ethanol mixtures), solvent pH (2-7), temperature (10-70°C), ultrasonic power (20-70%) and ultrasonic frequency (0.2-1.0s(-)(1)), were optimized to guarantee full recovery of the amino acids from grapes. An experimental design was employed to optimize the extraction parameters. The surface response methodology was used to evaluate the effects of the extraction variables. The analytical properties of the new method were established, including limit of detection (average value 1.4mmolkg(-)(1)), limit of quantification (average value 2.6mmolkg(-)(1)), repeatability (average RSD=12.9%) and reproducibility (average RSD=15.7%). Finally, the new method was applied to three cultivars of white grape throughout the ripening period. Copyright © 2014 Elsevier B.V. All rights reserved.

Metal cation dependence of interactions with amino acids: bond dissociation energies of Rb(+) and Cs(+) to the acidic amino acids and their amide derivatives.

PubMed

Armentrout, P B; Yang, Bo; Rodgers, M T

2014-04-24

Metal cation-amino acid interactions are key components controlling the secondary structure and biological function of proteins, enzymes, and macromolecular complexes comprising these species. Determination of pairwise interactions of alkali metal cations with amino acids provides a thermodynamic vocabulary that begins to quantify these fundamental processes. In the present work, we expand a systematic study of such interactions by examining rubidium and cesium cations binding with the acidic amino acids (AA), aspartic acid (Asp) and glutamic acid (Glu), and their amide derivatives, asparagine (Asn) and glutamine (Gln). These eight complexes are formed using electrospray ionization and their bond dissociation energies (BDEs) are determined experimentally using threshold collision-induced dissociation with xenon in a guided ion beam tandem mass spectrometer. Analyses of the energy-dependent cross sections include consideration of unimolecular decay rates, internal energy of the reactant ions, and multiple ion-neutral collisions. Quantum chemical calculations are conducted at the B3LYP, MP2(full), and M06 levels of theory using def2-TZVPPD basis sets, with results showing reasonable agreement with experiment. At 0 and 298 K, most levels of theory predict that the ground-state conformers for M(+)(Asp) and M(+)(Asn) involve tridentate binding of the metal cation to the backbone carbonyl, amino, and side-chain carbonyl groups, although tridentate binding to the carboxylic acid group and side-chain carbonyl is competitive for M(+)(Asn). For the two longer side-chain amino acids, Glu and Gln, multiple structures are competitive. A comparison of these results to those for the smaller alkali cations, Na(+) and K(+), provides insight into the trends in binding energies associated with the molecular polarizability and dipole moment of the side chain. For all four metal cations, the BDEs are inversely correlated with the size of the metal cation and follow the order Asp < Glu

Emerging Role of D-Amino Acid Metabolism in the Innate Defense.

PubMed

Sasabe, Jumpei; Suzuki, Masataka

2018-01-01

Mammalian innate and adaptive immune systems use the pattern recognition receptors, such as toll-like receptors, to detect conserved bacterial and viral components. Bacteria synthesize diverse D-amino acids while eukaryotes and archaea generally produce two D-amino acids, raising the possibility that many of bacterial D-amino acids are bacteria-specific metabolites. Although D-amino acids have not been identified to bind to any known pattern recognition receptors, D-amino acids are enantioselectively recognized by some other receptors and enzymes including a flavoenzyme D-amino acid oxidase (DAO) in mammals. At host-microbe interfaces in the neutrophils and intestinal mucosa, DAO catalyzes oxidation of bacterial D-amino acids, such as D-alanine, and generates H 2 O 2 , which is linked to antimicrobial activity. Intestinal DAO also modifies the composition of microbiota through modulation of growth for some bacteria that are dependent on host nutrition. Furthermore, regulation and recognition of D-amino acids in mammals have additional meanings at various host-microbe interfaces; D-phenylalanine and D-tryptophan regulate chemotaxis of neutrophils through a G-coupled protein receptor, D-serine has a bacteriostatic role in the urinary tract, D-phenylalanine and D-leucine inhibit innate immunity through the sweet taste receptor in the upper airway, and D-tryptophan modulates immune tolerance in the lower airway. This mini-review highlights recent evidence supporting the hypothesis that D-amino acids are utilized as inter-kingdom communication at host-microbe interface to modulate bacterial colonization and host defense.

Support Vector Machine-based classification of protein folds using the structural properties of amino acid residues and amino acid residue pairs.

PubMed

Shamim, Mohammad Tabrez Anwar; Anwaruddin, Mohammad; Nagarajaram, H A

2007-12-15

Fold recognition is a key step in the protein structure discovery process, especially when traditional sequence comparison methods fail to yield convincing structural homologies. Although many methods have been developed for protein fold recognition, their accuracies remain low. This can be attributed to insufficient exploitation of fold discriminatory features. We have developed a new method for protein fold recognition using structural information of amino acid residues and amino acid residue pairs. Since protein fold recognition can be treated as a protein fold classification problem, we have developed a Support Vector Machine (SVM) based classifier approach that uses secondary structural state and solvent accessibility state frequencies of amino acids and amino acid pairs as feature vectors. Among the individual properties examined secondary structural state frequencies of amino acids gave an overall accuracy of 65.2% for fold discrimination, which is better than the accuracy by any method reported so far in the literature. Combination of secondary structural state frequencies with solvent accessibility state frequencies of amino acids and amino acid pairs further improved the fold discrimination accuracy to more than 70%, which is approximately 8% higher than the best available method. In this study we have also tested, for the first time, an all-together multi-class method known as Crammer and Singer method for protein fold classification. Our studies reveal that the three multi-class classification methods, namely one versus all, one versus one and Crammer and Singer method, yield similar predictions. Dataset and stand-alone program are available upon request.

Study of antileishmanial activity of 2-aminobenzoyl amino acid hydrazides and their quinazoline derivatives.

PubMed

Khattab, Sherine Nabil; Haiba, Nesreen Saied; Asal, Ahmed Mosaad; Bekhit, Adnan A; Guemei, Aida A; Amer, Adel; El-Faham, Ayman

2017-02-15

A new small library of 2-aminobenzoyl amino acid hydrazide derivatives and quinazolinones derivatives was synthesized and fully characterized by IR, NMR, and elemental analysis. The activity of the prepared compounds on the growth of Leishmania aethiopica promastigotes was evaluated. 2-Benzoyl amino acid hydrazide showed higher inhibitory effect than the quinazoline counterpart. The in vitro antipromastigote activity demonstrated that compounds 2a, 2b, 2f and 4a had IC 50 better than standard drug miltefosine and comparable activity to amphotericin B deoxycholate, which indicates their high antileishmanial activity against Leishmania. aethiopica. Among the prepared compounds; 2-amino-N-(6-hydrazinyl-6-oxohexyl)benzamide 2f (IC 50 =0.051μM) has the best activity, 154 folds more active than reference standard drug miltefosine (IC 50 =7.832μM), and half fold the activity of amphotericin B (IC 50 =0.035μM). In addition, this compound was safe and well tolerated by experimental animals orally up to 250mg/kg and parenterally up to 100mg/kg. Copyright © 2017 Elsevier Ltd. All rights reserved.

Amino acids as antioxidants for frying oil

USDA-ARS?s Scientific Manuscript database

Amino acids, proteins and hydrolysates of proteins have been known to protect edible oils from oxidation. While amino acids and related materials have high potential as antioxidants for frying oil, effectiveness of each amino acid and mechanisms of their activities are not well understood yet. Propo...

Gemini surfactants from natural amino acids.

PubMed

Pérez, Lourdes; Pinazo, Aurora; Pons, Ramon; Infante, Mrosa

2014-03-01

In this review, we report the most important contributions in the structure, synthesis, physicochemical (surface adsorption, aggregation and phase behaviour) and biological properties (toxicity, antimicrobial activity and biodegradation) of Gemini natural amino acid-based surfactants, and some potential applications, with an emphasis on the use of these surfactants as non-viral delivery system agents. Gemini surfactants derived from basic (Arg, Lys), neutral (Ser, Ala, Sar), acid (Asp) and sulphur containing amino acids (Cys) as polar head groups, and Geminis with amino acids/peptides in the spacer chain are reviewed. © 2013.

Distinctive Roles of D-Amino Acids in the Homochiral World: Chirality of Amino Acids Modulates Mammalian Physiology and Pathology.

PubMed

Sasabe, Jumpei; Suzuki, Masataka

2018-05-22

Living organisms enantioselectively employ L-amino acids as the molecular architecture of protein synthesized in the ribosome. Although L-amino acids are dominantly utilized in most biological processes, accumulating evidence points to the distinctive roles of D-amino acids in non-ribosomal physiology. Among the three domains of life, bacteria have the greatest capacity to produce a wide variety of D-amino acids. In contrast, archaea and eukaryotes are thought generally to synthesize only two kinds of D-amino acids: D-serine and D-aspartate. In mammals, D-serine is critical for neurotransmission as an endogenous coagonist of N-methyl D-aspartate receptors. Additionally, D-aspartate is associated with neurogenesis and endocrine systems. Furthermore, recognition of D-amino acids originating in bacteria is linked to systemic and mucosal innate immunity. Among the roles played by D-amino acids in human pathology, the dysfunction of neurotransmission mediated by D-serine is implicated in psychiatric and neurological disorders. Non-enzymatic conversion of L-aspartate or L-serine residues to their D-configurations is involved in age-associated protein degeneration. Moreover, the measurement of plasma or urinary D-/L-serine or D-/L-aspartate levels may have diagnostic or prognostic value in the treatment of kidney diseases. This review aims to summarize current understanding of D-amino-acid-associated biology with a major focus on mammalian physiology and pathology.

Amino acids 16-275 of minute virus of mice NS1 include a domain that specifically binds (ACCA)2-3-containing DNA.

PubMed

Mouw, M; Pintel, D J

1998-11-10

GST-NS1 purified from Escherichia coli and insect cells binds double-strand DNA in an (ACCA)2-3-dependent fashion under similar ionic conditions, independent of the presence of anti-NS1 antisera or exogenously supplied ATP and interacts with single-strand DNA and RNA in a sequence-independent manner. An amino-terminal domain (amino acids 1-275) of NS1 [GST-NS1(1-275)], representing 41% of the full-length NS1 molecule, includes a domain that binds double-strand DNA in a sequence-specific manner at levels comparable to full-length GST-NS1, as well as single-strand DNA and RNA in a sequence-independent manner. The deletion of 15 additional amino-terminal amino acids yielded a molecule [GST-NS1(1-275)] that maintained (ACCA)2-3-specific double-strand DNA binding; however, this molecule was more sensitive to increasing ionic conditions than full-length GST-NS1 and GST-NS1(1-275) and could not be demonstrated to bind single-strand nucleic acids. A quantitative filter binding assay showed that E. coli- and baculovirus-expressed GST-NS1 and E. coli GST-NS1(1-275) specifically bound double-strand DNA with similar equilibrium kinetics [as measured by their apparent equilibrium DNA binding constants (KD)], whereas GST-NS1(16-275) bound 4- to 8-fold less well. Copyright 1998 Academic Press.

Amino acid metabolism in tumour-bearing mice.

PubMed Central

Rivera, S; Azcón-Bieto, J; López-Soriano, F J; Miralpeix, M; Argilés, J M

1988-01-01

Mice bearing the Lewis lung carcinoma showed a high tumour glutaminase activity and significantly higher concentrations of most amino acids than in both the liver and the skeletal muscle of the host. Tumour tissue slices showed a marked preference for glutamine, especially for oxidation of its skeleton to CO2. It is proposed that the metabolism of this particular carcinoma is focused on amino acid degradation, glutamine being its preferred substrate. PMID:3342022

Conformational preferences of 1-amino-2-phenylcyclohexanecarboxylic acid, a phenylalanine cyclohexane analogue

PubMed Central

Alemán, Carlos; Jiménez, Ana I.; Cativiela, Carlos; Nussinov, Ruth; Casanovas, Jordi

2009-01-01

The intrinsic conformational preferences of the restricted phenylalanine analogue generated by including the α and β carbon atoms into a cyclohexane ring (1-amino-2-phenylcyclohexanecarboxylic acid, c6Phe) have been determined using quantum mechanical calculations. Specifically, the conformational profile of the N-acetyl-N’-methylamide derivative of the c6Phe stereoisomers exhibiting either a cis or a trans relative orientation between the amino and phenyl substituents has been analyzed in different environments (gas phase, chloroform and aqueous solutions). Calculations were performed using B3LYP, MP2 and HF methods combined with the 6-31+G(d,p) and 6-311++G(d,p) basis sets, and a self-consistent reaction-field (SCRF) method was applied to analyze the influence of the solvent. The amino acids investigated can be viewed as constrained phenylalanine analogues with a rigidly oriented aromatic side chain that may interact with the peptide backbone not only sterically but also electronically through the aromatic π orbitals. Their conformational propensities have been found to be strongly influenced by the specific orientation of the aromatic substituent in each stereoisomer and the conformation adopted by the cyclohexane ring, as well as by the environment. PMID:19772338

Heterotrophic Potential for Amino Acid Uptake in a Naturally Eutrophic Lake1

PubMed Central

Burnison, B. Kent; Morita, Richard Y.

1974-01-01

The uptake of sixteen 14C-labeled amino acids by the indigenous heterotrophic microflora of Upper Klamath Lake, Oregon, was measured using the kinetic approach. The year-long study showed a seasonal variation in the maximum uptake velocity, Vmax, of all the amino acids which was proportional to temperature. The maximum total flux of amino acids by the heterotrophic microflora ranged from 1.2 to 11.9 μmol of C per liter per day (spring to summer). Glutamate, asparagine, aspartate, and serine had the highest Vmax values and were respired to the greatest extent. The percentages of the gross (net + respired) uptake of the amino acids which were respired to CO2 ranged from 2% for leucine to 63% for glutamate. Serine, lysine, and glycine were the most abundant amino acids found in Upper Klamath Lake surface water; at intermediate concentrations were alanine, aspartate, and threonine; and the remaining amino acids were always below 7.5 × 10-8 M (10 μg/liter). The amino acid concentrations determined chemically appear to be the sum of free and adsorbed amino acids, since the values obtained were usually greater than the (Kt + Sn) values obtained by the heterotrophic uptake experiments. PMID:4207581

The first proton sponge-based amino acids: synthesis, acid-base properties and some reactivity.

PubMed

Ozeryanskii, Valery A; Gorbacheva, Anastasia Yu; Pozharskii, Alexander F; Vlasenko, Marina P; Tereznikov, Alexander Yu; Chernov'yants, Margarita S

2015-08-21

The first hybrid base constructed from 1,8-bis(dimethylamino)naphthalene (proton sponge or DMAN) and glycine, N-methyl-N-(8-dimethylamino-1-naphthyl)aminoacetic acid, was synthesised in high yield and its hydrobromide was structurally characterised and used to determine the acid-base properties via potentiometric titration. It was found that the basic strength of the DMAN-glycine base (pKa = 11.57, H2O) is on the level of amidine amino acids like arginine and creatine and its structure, zwitterionic vs. neutral, based on the spectroscopic (IR, NMR, mass) and theoretical (DFT) approaches has a strong preference to the zwitterionic form. Unlike glycine, the DMAN-glycine zwitterion is N-chiral and is hydrolytically cleaved with the loss of glycolic acid on heating in DMSO. This reaction together with the mild decarboxylative conversion of proton sponge-based amino acids into 2,3-dihydroperimidinium salts under air-oxygen was monitored with the help of the DMAN-alanine amino acid. The newly devised amino acids are unique as they combine fluorescence, strongly basic and redox-active properties.

Concentration variations of amino acids in mammalian fossils: effects of diagenesis and the implications for amino acid racemization analysis

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

Blackwell, B.; Rutter, N.W.

Detailed amino acid analysis of bones, teeth, and antler from several mammal species have shown that concentrations of several amino acids can be related to three factors: type of material analyzed, diagenetic alteration of the material, and relative age of the fossil. Concentrations of several amino acids are significantly different in enamel compared to those of dentine or cement. This can be used to check that no contamination of one material by another has occurred, which is critical for using the data for amino acid dating, since all three materials have different racemization rates for some acids. With increased inmore » growth of secondary minerals, generally reduced amino acid concentrations are observed. Interacid ratios and concentrations vary significantly the norms expected for the type of material with increasing degrees of alteration. These effects can be linked to abnormal racemization ratios observed in the same samples. Therefore, abnormal concentrations and/or interacid ratios can be used to detect samples in which the D/L amino acid ratios otherwise appear normal, thereby insuring better accuracy of amino acid racemization analysis. For unaltered fossils, with increasing sample age regardless the type of material, some amino acids steadily degrade, while others actually increase in concentration initially due to their generation as by-products of decay. Preliminary studies indicate that this progressive alteration can used to complement racemization data for determining relative stratigraphic sequences.« less

Primordial synthesis of amines and amino acids in a 1958 Miller H2S-rich spark discharge experiment

PubMed Central

Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordial environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments. PMID:21422282

Primordial Synthesis of Amines and Amino Acids in a 1958 Miller H2S-Rich Spark Discharge Experiment

NASA Technical Reports Server (NTRS)

Parker, Eric T.; Cleaves, Henderson J.; Dworkin, Jason P.; Glavin, Daniel P.; Callahan, Michael; Aubrey, Andrew; Lazcano, Antonio; Bada, Jeffrey L.

2011-01-01

Archived samples from a previously unreported 1958 Stanley Miller electric discharge experiment containing hydrogen sulfide (H2S) were recently discovered and analyzed using high-performance liquid chromatography and time-of-flight mass spectrometry. We report here the detection and quantification of primary amine-containing compounds in the original sample residues, which were produced via spark discharge using a gaseous mixture of H2S, CH4, NH3, and CO2. A total of 23 amino acids and 4 amines, including 7 organosulfur compounds, were detected in these samples. The major amino acids with chiral centers are racemic within the accuracy of the measurements, indicating that they are not contaminants introduced during sample storage. This experiment marks the first synthesis of sulfur amino acids from spark discharge experiments designed to imitate primordia! environments. The relative yield of some amino acids, in particular the isomers of aminobutyric acid, are the highest ever found in a spark discharge experiment. The simulated primordial conditions used by Miller may serve as a model for early volcanic plume chemistry and provide insight to the possible roles such plumes may have played in abiotic organic synthesis. Additionally, the overall abundances of the synthesized amino acids in the presence of H2S are very similar to the abundances found in some carbonaceous meteorites, suggesting that H2S may have played an important role in prebiotic reactions in early solar system environments.

Dissolved Free Amino Acids in Hydrothermal Springs at Yellowstone National Park, U.S.A.

NASA Astrophysics Data System (ADS)

Cox, J. S.; Holland, M. E.; Shock, E. L.

2004-12-01

Insights into the organic geochemistry of hydrothermal systems, as well as the dynamics of biotic processes in hot spring ecosystems, can be gained by identifying and quantifying dissolved free amino acids (DFAA). Hydrothermal systems form a unique environmental subset relative to other aqueous settings due to their higher temperatures, largely uncharacterized and exotic microbiology, wider pH range, and elevated levels of rare metals, sulfur, and dissolved gases. Previous studies of hot spring and geothermal systems (e.g. Mukhin et al., 1979; Svensson et al., 2004) indicated the presence of micromolar quantities of various amino acids, but the underlying mechanisms controlling amino acid production and disappearance/consumption have continued to remain elusive. DFAA were identified and quantified in five hot springs at Yellowstone National Park that span a range of pH (2 to 8) and temperature (75 to 93° C/boiling). Biotic uptake experiments and enantiomeric analyses on samples from one location were also performed to elucidate biotic pathways. Analyses were performed using high pressure anion exchange chromatography with pulsed amperometric detection (HPAEC-PAD), which is able to resolve amino acids as well as certain carbohydrates, oligopeptides, and a variety of related biological molecules. Preliminary data indicate that total DFAA concentrations are quite low (sub-micromolar range) and that amino acids with aliphatic and nitrogen-containing R-groups are predominant in the DFAA fraction. The types and concentrations of amino acids were variable across the sites. Obsidian Pool (pH 5.1, 77.5° C), where multiple microbiological studies have been conducted, was found to have a DFAA fraction consisting primarily of glycine with trace amounts of arginine, lysine, and histidine. In comparison, an acidic spring in the Sylvan Springs area (pH 1.9, 79.7° C) had higher total DFAA concentrations and was found to contain primarily arginine, lysine, and leucine, together

Diverse characteristics of the urinary excretion of amino acids in humans and the use of amino acid supplementation to reduce fatigue and sub-health in adults.

PubMed

Dunstan, R H; Sparkes, D L; Macdonald, M M; De Jonge, X Janse; Dascombe, B J; Gottfries, J; Gottfries, C-G; Roberts, T K

2017-03-23

The excretion of amino acids in urine represents an important avenue for the loss of key nutrients. Some amino acids such as glycine and histidine are lost in higher abundance than others. These two amino acids perform important physiological functions and are required for the synthesis of key proteins such as haemoglobin and collagen. Stage 1 of this study involved healthy subjects (n = 151) who provided first of the morning urine samples and completed symptom questionnaires. Urine was analysed for amino acid composition by gas chromatography. Stage 2 involved a subset of the initial cohort (n = 37) who completed a 30 day trial of an amino acid supplement and subsequent symptom profile evaluation. Analyses of urinary amino acid profiles revealed that three groups could be objectively defined from the 151 participants using k-means clustering. The amino acid profiles were significantly different between each of the clusters (Wilks' Lambda = 0.13, p < 0.0001). Cluster 1 had the highest loss of amino acids with histidine being the most abundant component. Cluster 2 had glycine present as the most abundant urinary amino acid and cluster 3 had equivalent abundances of glycine and histidine. Strong associations were observed between urinary proline concentrations and fatigue/pain scores (r = .56 to .83) for females in cluster 1, with several other differential sets of associations observed for the other clusters. Different phenotypic subsets exist in the population based on amino acid excretion characteristics found in urine. Provision of the supplement resulted in significant improvements in reported fatigue and sleep for 81% of the trial cohort with all females reporting improvements in fatigue. The study was registered on the 18th April 2011 with the Australian New Zealand Clinical Trials Registry ( ACTRN12611000403932 ).

Amino Acid Sensing in Skeletal Muscle

PubMed Central

Moro, Tatiana; Ebert, Scott M.; Adams, Christopher M.; Rasmussen, Blake B.

2016-01-01

Aging impairs skeletal muscle protein synthesis, leading to muscle weakness and atrophy. However, the underlying molecular mechanisms remain poorly understood. Here, we review evidence that mTORC1- and ATF4-mediated amino acid sensing pathways, triggered by impaired amino acid delivery to aged skeletal muscle, may play important roles in skeletal muscle aging. Interventions that alleviate age-related impairments in muscle protein synthesis, strength and/or muscle mass appear to do so by reversing age-related changes in skeletal muscle amino acid delivery, mTORC1 activity and/or ATF4 activity. An improved understanding of the mechanisms and roles of amino acid sensing pathways in skeletal muscle may lead to evidence-based strategies to attenuate sarcopenia. PMID:27444066

Amino acid fermentation at the origin of the genetic code.

PubMed

de Vladar, Harold P

2012-02-10

into a proto-code that optimises the energetic yield. Monte Carlo simulations are performed to evaluate the establishment of these simple proto-codes, based on amino acid substitutions and codon swapping. In all cases, donor amino acids are assigned to anticodons composed of U+G, and have low redundancy (1-2 codons), whereas acceptor amino acids are assigned to the the remaining codons. These bioenergetic and structural constraints allow for a metabolic role for amino acids before their co-option as catalyst cofactors.

Branched-Chain Amino Acids.

PubMed

Yamamoto, Keisuke; Tsuchisaka, Atsunari; Yukawa, Hideaki

Branched-chain amino acids (BCAAs), viz., L-isoleucine, L-leucine, and L-valine, are essential amino acids that cannot be synthesized in higher organisms and are important nutrition for humans as well as livestock. They are also valued as synthetic intermediates for pharmaceuticals. Therefore, the demand for BCAAs in the feed and pharmaceutical industries is increasing continuously. Traditional industrial fermentative production of BCAAs was performed using microorganisms isolated by random mutagenesis. A collection of these classical strains was also scientifically useful to clarify the details of the BCAA biosynthetic pathways, which are tightly regulated by feedback inhibition and transcriptional attenuation. Based on this understanding of the metabolism of BCAAs, it is now possible for us to pursue strains with higher BCAA productivity using rational design and advanced molecular biology techniques. Additionally, systems biology approaches using augmented omics information help us to optimize carbon flux toward BCAA production. Here, we describe the biosynthetic pathways of BCAAs and their regulation and then overview the microorganisms developed for BCAA production. Other chemicals, including isobutanol, i.e., a second-generation biofuel, can be synthesized by branching the BCAA biosynthetic pathways, which are also outlined.

Structural investigation of (2E)-2-(ethoxycarbonyl)-3-[(4-methoxyphenyl)amino]prop-2-enoic acid: X-ray crystal structure, spectroscopy and DFT

NASA Astrophysics Data System (ADS)

Venkatesan, Perumal; Rajakannan, Venkatachalam; Venkataramanan, Natarajan S.; Ilangovan, Andivelu; Sundius, Tom; Thamotharan, Subbiah

2016-09-01

The title compound, (2E)-2-(ethoxycarbonyl)-3-[(4-methoxyphenyl)amino]prop-2-enoic acid is characterized by means of X-ray crystallography, spectroscopic methods and quantum chemical calculations. The title compound crystallizes in centrosymmetric space group P21/c. Moreover, the crystal structure is primarily stabilized through intramolecular Nsbnd H⋯O and Osbnd H⋯O and intermolecular Nsbnd H⋯O and Csbnd H⋯O interactions along with carbonyl⋯carbonyl and Csbnd H⋯C contacts. These intermolecular interactions are analysed and quantified by using Hirshfeld surface analysis, PIXEL energy, NBO, AIM and DFT calculations. The overall lattice energies of the title and parent compounds suggest that the title compound is stabilized by a 4.5 kcal mol-1 higher energy than the parent compound. The additional stabilization force comes from the methoxy substitution on the title molecule, which is evident since the methoxy group is involved in the intermolecular Csbnd H⋯O interaction as an acceptor. The vibrational modes of the interacting groups are investigated using both experimental and theoretical FT-IR and FT-Raman spectra. The experimental and theoretical UV-Vis spectra agree well. The time dependent DFT spectra show that the ligand-to-ligand charge transfer is responsible for the intense absorbance of the compound.

Formation of Amino Acid Thioesters for Prebiotic Peptide Synthesis: Catalysis By Amino Acid Products

NASA Technical Reports Server (NTRS)

Weber, Arthur L.; DeVincenzi, Donald L. (Technical Monitor)

1999-01-01

The origin of life can be described as a series of events in which a prebiotic chemical process came increasingly under the control of its catalytic products. In our search for this prebiotic process that yielded catalytic takeover products (such as polypeptides), we have been investigating a reaction system that generates peptide-forming amino acid thioesters from formaldehyde, glycolaldehyde, and ammonia in the presence of thiols. As shown below, this model process begins by aldol condensation of formaldehyde and glycolaldehyde to give trioses and releases. These sugars then undergo beta-dehydration yielding their respective alpha-ketoaldehydes. Addition of ammonia to the alpha-ketoaldehydes yields imines which can either: (a) rearrange in the presence of thesis to give amino acid thioesters or (be react with another molecule of aldehyde to give imidazoles. This 'one-pot' reaction system operates under mild aqueous conditions, and like modem amino acid biosynthesis, uses sugar intermediates which are converted to products by energy-yielding redox reactions. Recently, we discovered that amino acids, such as the alanine reaction product, catalyze the first and second steps of the process. In the presence of ammonia the process also generates other synthetically useful products, like the important biochemical -- pyruvic acid.

Amino Acid Metabolism in Acute Renal Failure: Influence of Intravenous Essential L-Amino Acid Hyperalimentation Therapy

PubMed Central

Abel, Ronald M.; Shih, Vivian E.; Abbott, William M.; Beck, Clyde H.; Fischer, Josef E.

1974-01-01

A solution of 8 essential I-amino acids and hypertonic dextrose was administered to 5 patients in acute postoperative renal failure in a program of hyperalimentation designed to decrease the patient's catabolic state and to accrue certain metabolic benefits. A sixth patient receiving intravenous glucose alone served as a control. The pretreatment plasma concentrations of amino acids in all 6 patients did not differ significantly from normal; following intravenous essential amino acids at a dose of approximately 12.6 gm/24 hours, no significant elevations out of the normal range of these substances occurred. Since urinary excretion rates did not dramatically increase, urinary loss was excluded as a possible cause for the failure of increase of plasma concentrations. The results suggest that the administration of an intravenous solution of 1-amino acids and hypertonic dextrose is associated with rapid clearance from the blood of these substances and, with a failure of increased urinary excretion, indirect evidence of amino acid utilization for protein synthesis has been obtained. Histidine supplementation in patients with acute renal failure is probably unnecessary based on the lack of significant decreases in histidine concentrations in these patients. PMID:4850497

Fed levels of amino acids are required for the somatotropin-induced increase in muscle protein synthesis

PubMed Central

Wilson, Fiona A.; Suryawan, Agus; Orellana, Renán A.; Nguyen, Hanh V.; Jeyapalan, Asumthia S.; Gazzaneo, Maria C.; Davis, Teresa A.

2008-01-01

Chronic somatotropin (pST) treatment in pigs increases muscle protein synthesis and circulating insulin, a known promoter of protein synthesis. Previously, we showed that the pST-mediated rise in insulin could not account for the pST-induced increase in muscle protein synthesis when amino acids were maintained at fasting levels. This study aimed to determine whether the pST-induced increase in insulin promotes skeletal muscle protein synthesis when amino acids are provided at fed levels and whether the response is associated with enhanced translation initiation factor activation. Growing pigs were treated with pST (0 or 180 μg·kg−1·day−1) for 7 days, and then pancreatic-glucose-amino acid clamps were performed. Amino acids were raised to fed levels in the presence of either fasted or fed insulin concentrations; glucose was maintained at fasting throughout. Muscle protein synthesis was increased by pST treatment and by amino acids (with or without insulin) (P < 0.001). In pST-treated pigs, fed, but not fasting, amino acid concentrations further increased muscle protein synthesis rates irrespective of insulin level (P < 0.02). Fed amino acids, with or without raised insulin concentrations, increased the phosphorylation of S6 kinase (S6K1) and eukaryotic initiation factor (eIF) 4E-binding protein 1 (4EBP1), decreased inactive 4EBP1·eIF4E complex association, and increased active eIF4E·eIF4G complex formation (P < 0.02). pST treatment did not alter translation initiation factor activation. We conclude that the pST-induced stimulation of muscle protein synthesis requires fed amino acid levels, but not fed insulin levels. However, under the current conditions, the response to amino acids is not mediated by the activation of translation initiation factors that regulate mRNA binding to the ribosomal complex. PMID:18682537

Far Infrared spectroscopy of proteinogenic and other less common amino acids

NASA Astrophysics Data System (ADS)

Iglesias-Groth, S.; Cataldo, F.

2018-05-01

Far infrared spectroscopy is a powerful tool complementing the potential of mid infrared spectroscopy for the search and identification of organic molecules in space. The far infrared spectra of a total of 29 amino acids are reported in this study. In addition to the spectra of 20 common proteinogenic amino acids, spectra of a selection of 9 non-proteinogenic amino acids are also reported, including the 2-aminoisobutyric acid or α-aminoisobutyric acid which, with glycine, it is one of the most abundant amino acids found in meteorites. The present database of 29 far infrared spectra may serve as reference in the search for amino acids in space environments, given the new apportunities that JWST offers for mid and far IR spectroscopy.

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.

Site specific incorporation of heavy atom-containing unnatural amino acids into proteins for structure determination

DOEpatents

Xie, Jianming [San Diego, CA; Wang, Lei [San Diego, CA; Wu, Ning [Boston, MA; Schultz, Peter G [La Jolla, CA

2008-07-15

Translation systems and other compositions including orthogonal aminoacyl tRNA-synthetases that preferentially charge an orthogonal tRNA with an iodinated or brominated amino acid are provided. Nucleic acids encoding such synthetases are also described, as are methods and kits for producing proteins including heavy atom-containing amino acids, e.g., brominated or iodinated amino acids. Methods of determining the structure of a protein, e.g., a protein into which a heavy atom has been site-specifically incorporated through use of an orthogonal tRNA/aminoacyl tRNA-synthetase pair, are also described.

Acquired Amino Acid Deficiencies: A Focus on Arginine and Glutamine.

PubMed

Morris, Claudia R; Hamilton-Reeves, Jill; Martindale, Robert G; Sarav, Menaka; Ochoa Gautier, Juan B

2017-04-01

Nonessential amino acids are synthesized de novo and therefore not diet dependent. In contrast, essential amino acids must be obtained through nutrition since they cannot be synthesized internally. Several nonessential amino acids may become essential under conditions of stress and catabolic states when the capacity of endogenous amino acid synthesis is exceeded. Arginine and glutamine are 2 such conditionally essential amino acids and are the focus of this review. Low arginine bioavailability plays a pivotal role in the pathogenesis of a growing number of varied diseases, including sickle cell disease, thalassemia, malaria, acute asthma, cystic fibrosis, pulmonary hypertension, cardiovascular disease, certain cancers, and trauma, among others. Catabolism of arginine by arginase enzymes is the most common cause of an acquired arginine deficiency syndrome, frequently contributing to endothelial dysfunction and/or T-cell dysfunction, depending on the clinical scenario and disease state. Glutamine, an arginine precursor, is one of the most abundant amino acids in the body and, like arginine, becomes deficient in several conditions of stress, including critical illness, trauma, infection, cancer, and gastrointestinal disorders. At-risk populations are discussed together with therapeutic options that target these specific acquired amino acid deficiencies.

Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

NASA Technical Reports Server (NTRS)

Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.; Bruckner, H.

2010-01-01

The presence of non-protein alpha-dialkyl-amino acids such as alpha-aminoisobutyric acid (alpha-A1B) and isovaline (Iva), which are relatively rare in the terrestrial biosphere, has long been used as an indication of the indigeneity of meteoritic amino acids, however, the discovery of alpha-AIB in peptides producers by a widespread group of filamentous fungi indicates the possibility of a terrestrial biotic source for the alpha-AIB observed in some meteorites. The alpha-AIB-containing peptides produced by these fungi are dubbed peptaibiotics. We measured the molecular distribution and stable carbon and nitrogen isotopic ratios for amino acids found in the total hydrolysates of four biologically synthesized peptaibiotics. We compared these aneasurenetts with those from the CM2 carbonaceous chondrite Murchison and from three Antarctic CR2 carbonaceous chondrites in order to understand the peptaibiotics as a potential source of meteoritic contamination.

Functional analysis of fructosyl-amino acid oxidases of Aspergillus oryzae.

PubMed

Akazawa, Shin-Ichi; Karino, Tetsuya; Yoshida, Nobuyuki; Katsuragi, Tohoru; Tani, Yoshiki

2004-10-01

Three active fractions of fructosyl-amino acid oxidase (FAOD-Ao1, -Ao2a, and -Ao2b) were isolated from Aspergillus oryzae strain RIB40. N-terminal and internal amino acid sequences of FAOD-Ao2a corresponded to those of FAOD-Ao2b, suggesting that these two isozymes were derived from the same protein. FAOD-Ao1 and -Ao2 were different in substrate specificity and subunit assembly; FAOD-Ao2 was active toward N(epsilon)-fructosyl N(alpha)-Z-lysine and fructosyl valine (Fru-Val), whereas FAOD-Ao1 was not active toward Fru-Val. The genes encoding the FAOD isozymes (i.e., FAOAo1 and FAOAo2) were cloned by PCR with an FAOD-specific primer set. The deduced amino acid sequences revealed that FAOD-Ao1 was 50% identical to FAOD-Ao2, and each isozyme had a peroxisome-targeting signal-1, indicating their localization in peroxisomes. The genes was expressed in Escherichia coli and rFaoAo2 showed the same characteristics as FAOD-Ao2, whereas rFaoAo1 was not active. FAOAo2 disruptant was obtained by using ptrA as a selective marker. Wild-type strain grew on the medium containing Fru-Val as the sole carbon and nitrogen sources, but strain Delta faoAo2 did not grow. Addition of glucose or (NH(4))(2)SO(4) to the Fru-Val medium did not affect the assimilation of Fru-Val by wild-type, indicating glucose and ammonium repressions did not occur in the expression of the FAOAo2 gene. Furthermore, conidia of the wild-type strain did not germinate on the medium containing Fru-Val and NaNO(2) as the sole carbon and nitrogen sources, respectively, suggesting that Fru-Val may also repress gene expression of nitrite reductase. These results indicated that FAOD is needed for utilization of fructosyl-amino acids as nitrogen sources in A. oryzae.

Regulation of Intestinal Epithelial Cells Properties and Functions by Amino Acids.

PubMed

Kong, Shanshan; Zhang, Yanhui H; Zhang, Weiqiang

2018-01-01

Intestinal epithelial cells (IECs) line the surface of intestinal epithelium, where they play important roles in the digestion of food, absorption of nutrients, and protection of the human body from microbial infections, and others. Dysfunction of IECs can cause diseases. The development, maintenance, and functions of IECs are strongly influenced by external nutrition, such as amino acids. Amino acids play important roles in regulating the properties and functions of IECs. In this article, we briefly reviewed the current understanding of the roles of amino acids in the regulation of IECs' properties and functions in physiological state, including in IECs homeostasis (differentiation, proliferation, and renewal), in intestinal epithelial barrier structure and functions, and in immune responses. We also summarized some important findings on the effects of amino acids supplementation (e.g., glutamine and arginine) in restoring IECs' and intestine functions in some diseased states. These findings will further our understanding of the important roles of amino acids in the homeostasis of IECs and could potentially help identify novel targets and reagents for the therapeutic interventions of diseases associated with dysfunctional IECs.