Life Before RNA

NASA Astrophysics Data System (ADS)

Sowerby, Stephen J.; Petersen, George B.

2002-08-01

The hypothesis that life originated and evolved from linear informational molecules capable of facilitating their own catalytic replication is deeply entrenched. However, widespread acceptance of this paradigm seems oblivious to a lack of direct experimental support. Here, we outline the fundamental objections to the de novo appearance of linear, self-replicating polymers and examine an alternative hypothesis of template-directed coding of peptide catalysts by adsorbed purine bases. The bases (which encode biological information in modern nucleic acids) spontaneously self-organize into two-dimensional molecular solids adsorbed to the uncharged surfaces of crystalline minerals; their molecular arrangement is specified by hydrogen bonding rules between adjacent molecules and can possess the aperiodic complexity to encode putative protobiological information. The persistence of such information through self-reproduction, together with the capacity of adsorbed bases to exhibit enantiomorphism and effect amino acid discrimination, would seem to provide the necessary machinery for a primitive genetic coding mechanism.

Cleavage-site specificity of prolyl endopeptidase FAP investigated with a full-length protein substrate.

PubMed

Huang, Chih-Hsiang; Suen, Ching-Shu; Lin, Ching-Ting; Chien, Chia-Hui; Lee, Hsin-Ying; Chung, Kuei-Min; Tsai, Ting-Yueh; Jiaang, Weir-Tong; Hwang, Ming-Jing; Chen, Xin

2011-06-01

Fibroblast activation protein (FAP) is a prolyl-cleaving endopeptidase proposed as an anti-cancer drug target. It is necessary to define its cleavage-site specificity to facilitate the identification of its in vivo substrates and to understand its biological functions. We found that the previously identified substrate of FAP, α(2)-anti-plasmin, is not a robust substrate in vitro. Instead, an intracellular protein, SPRY2, is cleavable by FAP and more suitable for investigation of its substrate specificity in the context of the full-length globular protein. FAP prefers uncharged residues, including small or bulky hydrophobic amino acids, but not charged amino acids, especially acidic residue at P1', P3 and P4 sites. Molecular modelling analysis shows that the substrate-binding site of FAP is surrounded by multiple tyrosine residues and some negatively charged residues, which may exert least preference for substrates with acidic residues. This provides an explanation why FAP cannot cleave interleukins, which have a glutamate at either P4 or P2', despite their P3-P2-P1 sites being identical to SPRY2 or α-AP. Our study provided new information on FAP cleavage-site specificity, which differs from the data obtained by profiling with a peptide library or with the denatured protein, gelatin, as the substrate. Furthermore, our study suggests that negatively charged residues should be avoided when designing FAP inhibitors.

Elastin-like Polypeptide (ELP) Charge Influences Self-Assembly of ELP-mCherry Fusion Proteins.

PubMed

Mills, Carolyn E; Michaud, Zachary; Olsen, Bradley D

2018-05-23

Self-assembly of protein-polymer bioconjugates presents an elegant strategy for controlling nanostructure and orientation of globular proteins in functional materials. Recent work has shown that genetic fusion of globular protein mCherry to an elastin-like polypeptide (ELP) yields similar self-assembly behavior to these protein-polymer bioconjugates. In the context of studying protein-polymer bioconjugate self-assembly, the mutability of the ELP sequence allows several different properties of the ELP block to be tuned orthogonally while maintaining consistent polypeptide backbone chemistry. This work uses this ELP sequence tunability in combination with the precise control offered by genetic engineering of an amino acid sequence to generate a library of four novel ELP sequences that are used to study the combined effect of charge and hydrophobicity on ELP-mCherry fusion protein self-assembly. Concentrated solution self-assembly is studied by small-angle X-ray scattering (SAXS) and depolarized light scattering (DPLS). These experiments show that fusions containing a negatively charged ELP block do not assemble at all, and fusions with a charge balanced ELP block exhibit a weak propensity for assembly. By comparison, the fusion containing an uncharged ELP block starts to order at 40 wt % in solution and at all concentrations measured has sharper, more intense SAXS peaks than other fusion proteins. These experiments show that charge character of the ELP block is a stronger predictor of self-assembly behavior than the hydrophobicity of the ELP block. Dilute solution small-angle neutron scattering (SANS) on the ELPs alone suggests that all ELPs used in this study (including the uncharged ELP) adopt dilute solution conformations similar to those of traditional polymers, including polyampholytes and polyelectrolytes. Finally, dynamic light scattering studies on ELP-mCherry blends shows that there is no significant complexation between the charged ELPs and mCherry. Therefore, it is proposed that the superior self-assembly of fusion proteins containing uncharged ELP block is due to effective repulsions between charged and uncharged blocks due to local charge correlation effects and, in the case of anionic ELPs, repulsion between like charges within the ELP block.

Positions of Trp Codons in the Leader Peptide-Coding Region of the at Operon Influence Anti-Trap Synthesis and trp Operon Expression in Bacillus licheniformis▿

PubMed Central

Levitin, Anastasia; Yanofsky, Charles

2010-01-01

Tryptophan, phenylalanine, tyrosine, and several other metabolites are all synthesized from a common precursor, chorismic acid. Since tryptophan is a product of an energetically expensive biosynthetic pathway, bacteria have developed sensing mechanisms to downregulate synthesis of the enzymes of tryptophan formation when synthesis of the amino acid is not needed. In Bacillus subtilis and some other Gram-positive bacteria, trp operon expression is regulated by two proteins, TRAP (the tryptophan-activated RNA binding protein) and AT (the anti-TRAP protein). TRAP is activated by bound tryptophan, and AT synthesis is increased upon accumulation of uncharged tRNATrp. Tryptophan-activated TRAP binds to trp operon leader RNA, generating a terminator structure that promotes transcription termination. AT binds to tryptophan-activated TRAP, inhibiting its RNA binding ability. In B. subtilis, AT synthesis is upregulated both transcriptionally and translationally in response to the accumulation of uncharged tRNATrp. In this paper, we focus on explaining the differences in organization and regulatory functions of the at operon's leader peptide-coding region, rtpLP, of B. subtilis and Bacillus licheniformis. Our objective was to correlate the greater growth sensitivity of B. licheniformis to tryptophan starvation with the spacing of the three Trp codons in its at operon leader peptide-coding region. Our findings suggest that the Trp codon location in rtpLP of B. licheniformis is designed to allow a mild charged-tRNATrp deficiency to expose the Shine-Dalgarno sequence and start codon for the AT protein, leading to increased AT synthesis. PMID:20061467

Immunocytochemistry by electron spectroscopic imaging using a homogeneously boronated peptide.

PubMed

Kessels, M M; Qualmann, B; Klobasa, F; Sierralta, W D

1996-05-01

A linear all-L-oligopeptide containing five carboranyl amino acids (corresponding to 50 boron atoms) was synthesized and specifically attached to the free thiol group of monovalent antibody fragments F(ab)'. The boronated immunoreagent was used for the direct post-embedding detection of somatotrophic hormone in ultrathin sections of porcine pituitary embedded in Spurr resin. The specific boron-labelling of secretory vesicles in somatotrophs was detected by electron spectroscopic imaging and confirmed by conventional immunogold labelling run in parallel. In comparison with immunogold, boron-labelled F(ab)'-fragments showed higher tagging frequencies, as was expected; the small uncharged immunoreagents have an elongated shape and carry the antigen-combining structure and the detection tag at opposite ends, thus allowing for high spatial resolution in electron spectroscopic imaging.

Interaction of anesthetic molecules with α-helix and polyproline II extended helix of long-chain poly-L-lysine

NASA Astrophysics Data System (ADS)

Cieślik-Boczula, Katarzyna; Rospenk, Maria

2018-01-01

The effect of halothane, enflurane, sevoflurane, and isoflurane molecules, as volatile anesthetics, on the α-helices and polyproline II extended helices (PPII) of long-chain poly-L-lysine (PLL) were studied using Fourier-transform infrared and vibrational circular dichroism spectroscopy. Uncharged and charged α-helices, as well as charged extended PPII helices, were subjected to anesthetic actions in solvents with different pD values or methanol to water ratios. A crucial factor responsible for hindering the anesthetic-PLL interactions is shown to be the ionization of amino groups of the PLL side chains. The α-helix to β-sheet transition was triggered only for the uncharged α-helical structures of PLL by the nonpolar anesthetics under study.

Molecular modeling and analysis of human and plant endo-β-N-acetyl- glucosaminidases for mutations effects on function

PubMed Central

Choragudi, Shechinah Felice; Veeramachaneni, Ganesh Kumar; Raman, BV; JS, Bondili

2014-01-01

Endo- β-N-acetylgucosaminidases (ENGases) are the enzymes that catalyze both hydrolysis and transglycosylation reactions. It is of interest to study ENGases because of their ability to synthesize glycopeptides. Homology models of Human, Arabidopsis thaliana and Sorghum ENGases were developed and their active sites marked based on information available from Arthrobacter protophormiae (PDB ID: 3FHQ) ENGase. Further, these models were docked with the natural substrate GlcNAc-Asn and the inhibitor Man3GlcNAc-thiazoline. The catalytic triad of Asn, Glu and Tyr (N171, E173 and Y205 of bacteria) were found to be conserved across the phyla. The crucial Y299F mutation showing 3 times higher transglycosylation activity than in wild type Endo-A is known. The hydrolytic activity remained unchanged in bacteria, while the transglycosylation activity increased. This Y to F change is found to be naturally evolved and should be attributing higher transglycosylation rates in human and Arabidopsis thaliana ENGases. Ligand interactions Ligplots revealed the interaction of amino acids with hydrophobic side chains and polar uncharged side chain amino acids. Thus, structure based molecular model-ligand interactions provide insights into the catalytic mechanism of ENGases and assist in the rational engineering of ENGases. PMID:25258486

Molecular modeling and analysis of human and plant endo-β-N-acetyl- glucosaminidases for mutations effects on function.

PubMed

Choragudi, Shechinah Felice; Veeramachaneni, Ganesh Kumar; Raman, Bv; Js, Bondili

2014-01-01

Endo- β-N-acetylgucosaminidases (ENGases) are the enzymes that catalyze both hydrolysis and transglycosylation reactions. It is of interest to study ENGases because of their ability to synthesize glycopeptides. Homology models of Human, Arabidopsis thaliana and Sorghum ENGases were developed and their active sites marked based on information available from Arthrobacter protophormiae (PDB ID: 3FHQ) ENGase. Further, these models were docked with the natural substrate GlcNAc-Asn and the inhibitor Man3GlcNAc-thiazoline. The catalytic triad of Asn, Glu and Tyr (N171, E173 and Y205 of bacteria) were found to be conserved across the phyla. The crucial Y299F mutation showing 3 times higher transglycosylation activity than in wild type Endo-A is known. The hydrolytic activity remained unchanged in bacteria, while the transglycosylation activity increased. This Y to F change is found to be naturally evolved and should be attributing higher transglycosylation rates in human and Arabidopsis thaliana ENGases. Ligand interactions Ligplots revealed the interaction of amino acids with hydrophobic side chains and polar uncharged side chain amino acids. Thus, structure based molecular model-ligand interactions provide insights into the catalytic mechanism of ENGases and assist in the rational engineering of ENGases.

Molecular envelope and atomic model of an anti-terminated glyQS T-box regulator in complex with tRNAGly

PubMed Central

Chetnani, Bhaskar

2017-01-01

Abstract A T-box regulator or riboswitch actively monitors the levels of charged/uncharged tRNA and participates in amino acid homeostasis by regulating genes involved in their utilization or biosynthesis. It has an aptamer domain for cognate tRNA recognition and an expression platform to sense the charge state and modulate gene expression. These two conserved domains are connected by a variable linker that harbors additional secondary structural elements, such as Stem III. The structural basis for specific tRNA binding is known, but the structural basis for charge sensing and the role of other elements remains elusive. To gain new structural insights on the T-box mechanism, a molecular envelope was calculated from small angle X-ray scattering data for the Bacillus subtilis glyQS T-box riboswitch in complex with an uncharged tRNAGly. A structural model of an anti-terminated glyQS T-box in complex with its cognate tRNAGly was derived based on the molecular envelope. It shows the location and relative orientation of various secondary structural elements. The model was validated by comparing the envelopes of the wild-type complex and two variants. The structural model suggests that in addition to a possible regulatory role, Stem III could aid in preferential stabilization of the T-box anti-terminated state allowing read-through of regulated genes. PMID:28531275

The Aquaporin Splice Variant NbXIP1;1α Is Permeable to Boric Acid and Is Phosphorylated in the N-terminal Domain

PubMed Central

Ampah-Korsah, Henry; Anderberg, Hanna I.; Engfors, Angelica; Kirscht, Andreas; Norden, Kristina; Kjellstrom, Sven; Kjellbom, Per; Johanson, Urban

2016-01-01

Aquaporins (AQPs) are membrane channel proteins that transport water and uncharged solutes across different membranes in organisms in all kingdoms of life. In plants, the AQPs can be divided into seven different subfamilies and five of these are present in higher plants. The most recently characterized of these subfamilies is the XIP subfamily, which is found in most dicots but not in monocots. In this article, we present data on two different splice variants (α and β) of NbXIP1;1 from Nicotiana benthamiana. We describe the heterologous expression of NbXIP1;1α and β in the yeast Pichia pastoris, the subcellular localization of the protein in this system and the purification of the NbXIP1;1α protein. Furthermore, we investigated the functionality and the substrate specificity of the protein by stopped-flow spectrometry in P. pastoris spheroplasts and with the protein reconstituted in proteoliposomes. The phosphorylation status of the protein and localization of the phosphorylated amino acids were verified by mass spectrometry. Our results show that NbXIP1;1α is located in the plasma membrane when expressed in P. pastoris, that it is not permeable to water but to boric acid and that the protein is phosphorylated at several amino acids in the N-terminal cytoplasmic domain of the protein. A growth assay showed that the yeast cells expressing the N-terminally His-tagged NbXIP1;1α were more sensitive to boric acid as compared to the cells expressing the C-terminally His-tagged isoform. This might suggest that the N-terminal His-tag functionally mimics the phosphorylation of the N-terminal domain and that the N-terminal domain is involved in gating of the channel. PMID:27379142

Cysteine Transport through Excitatory Amino Acid Transporter 3 (EAAT3)

PubMed Central

Watts, Spencer D.; Torres-Salazar, Delany; Divito, Christopher B.; Amara, Susan G.

2014-01-01

Excitatory amino acid transporters (EAATs) limit glutamatergic signaling and maintain extracellular glutamate concentrations below neurotoxic levels. Of the five known EAAT isoforms (EAATs 1–5), only the neuronal isoform, EAAT3 (EAAC1), can efficiently transport the uncharged amino acid L-cysteine. EAAT3-mediated cysteine transport has been proposed to be a primary mechanism used by neurons to obtain cysteine for the synthesis of glutathione, a key molecule in preventing oxidative stress and neuronal toxicity. The molecular mechanisms underlying the selective transport of cysteine by EAAT3 have not been elucidated. Here we propose that the transport of cysteine through EAAT3 requires formation of the thiolate form of cysteine in the binding site. Using Xenopus oocytes and HEK293 cells expressing EAAT2 and EAAT3, we assessed the transport kinetics of different substrates and measured transporter-associated currents electrophysiologically. Our results show that L-selenocysteine, a cysteine analog that forms a negatively-charged selenolate ion at physiological pH, is efficiently transported by EAATs 1–3 and has a much higher apparent affinity for transport when compared to cysteine. Using a membrane tethered GFP variant to monitor intracellular pH changes associated with transport activity, we observed that transport of either L-glutamate or L-selenocysteine by EAAT3 decreased intracellular pH, whereas transport of cysteine resulted in cytoplasmic alkalinization. No change in pH was observed when cysteine was applied to cells expressing EAAT2, which displays negligible transport of cysteine. Under conditions that favor release of intracellular substrates through EAAT3 we observed release of labeled intracellular glutamate but did not detect cysteine release. Our results support a model whereby cysteine transport through EAAT3 is facilitated through cysteine de-protonation and that once inside, the thiolate is rapidly re-protonated. Moreover, these findings suggest that cysteine transport is predominantly unidirectional and that reverse transport does not contribute to depletion of intracellular cysteine pools. PMID:25275463

Charge and Geometry of Residues in the Loop 2 β Hairpin Differentially Affect Agonist and Ethanol Sensitivity in Glycine Receptors

PubMed Central

Perkins, Daya I.; Trudell, James R.; Asatryan, Liana; Alkana, Ronald L.

2012-01-01

Recent studies highlighted the importance of loop 2 of α1 glycine receptors (GlyRs) in the propagation of ligand-binding energy to the channel gate. Mutations that changed polarity at position 52 in the β hairpin of loop 2 significantly affected sensitivity to ethanol. The present study extends the investigation to charged residues. We found that substituting alanine with the negative glutamate at position 52 (A52E) significantly left-shifted the glycine concentration response curve and increased sensitivity to ethanol, whereas the negative aspartate substitution (A52D) significantly right-shifted the glycine EC50 but did not affect ethanol sensitivity. It is noteworthy that the uncharged glutamine at position 52 (A52Q) caused only a small right shift of the glycine EC50 while increasing ethanol sensitivity as much as A52E. In contrast, the shorter uncharged asparagine (A52N) caused the greatest right shift of glycine EC50 and reduced ethanol sensitivity to half of wild type. Collectively, these findings suggest that charge interactions determined by the specific geometry of the amino acid at position 52 (e.g., the 1-Å chain length difference between aspartate and glutamate) play differential roles in receptor sensitivity to agonist and ethanol. We interpret these results in terms of a new homology model of GlyR based on a prokaryotic ion channel and propose that these mutations form salt bridges to residues across the β hairpin (A52E-R59 and A52N-D57). We hypothesize that these electrostatic interactions distort loop 2, thereby changing agonist activation and ethanol modulation. This knowledge will help to define the key physical-chemical parameters that cause the actions of ethanol in GlyRs. PMID:22357974

Conformational and chemical selection by a trans-acting editing domain

PubMed Central

Danhart, Eric M.; Bakhtina, Marina; Cantara, William A.; Kuzmishin, Alexandra B.; Ma, Xiao; Sanford, Brianne L.; Vargas-Rodriguez, Oscar; Košutić, Marija; Goto, Yuki; Suga, Hiroaki; Nakanishi, Kotaro; Micura, Ronald; Musier-Forsyth, Karin

2017-01-01

Molecular sieves ensure proper pairing of tRNAs and amino acids during aminoacyl-tRNA biosynthesis, thereby avoiding detrimental effects of mistranslation on cell growth and viability. Mischarging errors are often corrected through the activity of specialized editing domains present in some aminoacyl-tRNA synthetases or via single-domain trans-editing proteins. ProXp-ala is a ubiquitous trans-editing enzyme that edits Ala-tRNAPro, the product of Ala mischarging by prolyl-tRNA synthetase, although the structural basis for discrimination between correctly charged Pro-tRNAPro and mischarged Ala-tRNAAla is unclear. Deacylation assays using substrate analogs reveal that size discrimination is only one component of selectivity. We used NMR spectroscopy and sequence conservation to guide extensive site-directed mutagenesis of Caulobacter crescentus ProXp-ala, along with binding and deacylation assays to map specificity determinants. Chemical shift perturbations induced by an uncharged tRNAPro acceptor stem mimic, microhelixPro, or a nonhydrolyzable mischarged Ala-microhelixPro substrate analog identified residues important for binding and deacylation. Backbone 15N NMR relaxation experiments revealed dynamics for a helix flanking the substrate binding site in free ProXp-ala, likely reflecting sampling of open and closed conformations. Dynamics persist on binding to the uncharged microhelix, but are attenuated when the stably mischarged analog is bound. Computational docking and molecular dynamics simulations provide structural context for these findings and predict a role for the substrate primary α-amine group in substrate recognition. Overall, our results illuminate strategies used by a trans-editing domain to ensure acceptance of only mischarged Ala-tRNAPro, including conformational selection by a dynamic helix, size-based exclusion, and optimal positioning of substrate chemical groups. PMID:28768811

Omega-oxidation impairs oxidizability of polyenoic fatty acids by 15-lipoxygenases: consequences for substrate orientation at the active site.

PubMed Central

Ivanov, I; Schwarz, K; Holzhütter, H G; Myagkova, G; Kühn, H

1998-01-01

During oxygenation by 15-lipoxygenases, polyenoic fatty acids are bound at the active site in such a way that the omega-terminus of the fatty acids penetrates into the substrate binding pocket. In contrast, for arachidonic acid 5-lipoxygenation, an inverse head to tail orientation has been suggested. However, an inverse orientation may be hindered by the large energy barrier associated with burying the charged carboxylate group in the hydrophobic environment of the substrate binding cleft. We studied the oxygenation kinetics of omega-modified fatty acids by 15-lipoxygenases and found that omega-hydroxylation strongly impaired substrate affinity (higher Km), but only moderately altered Vmax. In contrast, omega-carboxylation completely prevented the lipoxygenase reaction; however, methylation of the additional carboxylate group restored the activity. Arg403 of the human 15-lipoxygenase has been implicated in fatty acid binding by forming a salt bridge with the carboxylate group, and thus mutation of this amino acid to an uncharged residue was supposed to favour an inverse substrate orientation. The prepared Arg403-->Leu mutant of the rabbit 15-lipoxygenase was found to be a less effective catalyst of linoleic acid oxygenation. However, the oxygenation rate of omega-hydroxyarachidonic acid was similar when the wild-type and mutant enzyme were compared, and the patterns of oxygenation products were identical for both enzyme species. These data suggest that introduction of a polar, or even charged residue, at the omega-terminus of substrate fatty acids in connection with mutation of Arg403 may not alter substrate alignment at the active site of 15-lipoxygenases. PMID:9820810

A new mutation in the CFTR gene, composed of two adjacent DNA alterations, is a common cause of cystic fibrosis among Georgian Jews

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

Shoshani, T.; Berkun, Y.; Yahav, Y.

Five Jewish cystic fibrosis (CF) patients from four unrelated families, all of whom emigrated from what was Soviet Georgia were studied. The parents in two of the families are first-degree relatives. The clinical phenotype of the patients seems to be associated with a severe disease, as reflected by early age of diagnosis (before the age of 1 year), high sweat chloride level (105-140 meq/liter), and pancreatic insufficiency. The pulmonary function and nutritional status of these patients are normal. These patients were tested for [Delta]F508 by analysis of heteroduplex DNA (4). None of the CF chromosomes was found to carry themore » [Delta]F508 mutation. Subsequently, PCR-amplified genomic DNA samples from two of these patients were subjected to direct sequencing (5) of regions containing exons 7, 9-12, an 19-21 of the CF gene using the oligonucleotides previously described (3, 6). In exon 7, two DNA alterations 3 bp apart were identified in both patients. The first alteration in a C [yields] A transversion at nucleotide position 1207, changing the glutamine codon to lysine (Q359K). The second DNA alteration is a C [yields] A transversion at nucleotide position 1211 changing the threonine codon to lysine (T360K). The two DNA alterations cause nonconservative amino acid substitutions, changing each of the two uncharged polar amino acids (glutamine and threonine) to a basic amino acid, lysine. The Q359K substitution destroys an Rsal recognition site and can be detected by PCR amplification of exon 7 using 7i-5 and 7i-3 oligonucleotides (6), followed by Rsal digestion and electrophoresis on 10% polyacrylamide gels. Two Rsal sites are found in a normal amplified DNA fragment, resulting in three restriction fragments of 292, 68, and 50 bp. Digestion of the PCR fragment of an individual homozygous for this substitution resulted in only two fragments of 342 and 68 bp. 6 refs., 3 figs.« less

Thermodynamics and Mechanism of the Interaction of Willardiine Partial Agonists with a Glutamate Receptor: Implications for Drug Development

PubMed Central

2015-01-01

Understanding the thermodynamics of binding of a lead compound to a receptor can provide valuable information for drug design. The binding of compounds, particularly partial agonists, to subtypes of the α-amino-3-hydroxy-5-methyl-4-isoxazole-propionic acid (AMPA) receptor is, in some cases, driven by increases in entropy. Using a series of partial agonists based on the structure of the natural product, willardiine, we show that the charged state of the ligand determines the enthalpic contribution to binding. Willardiines have uracil rings with pKa values ranging from 5.5 to 10. The binding of the charged form is largely driven by enthalpy, while that of the uncharged form is largely driven by entropy. This is due at least in part to changes in the hydrogen bonding network within the binding site involving one water molecule. This work illustrates the importance of charge to the thermodynamics of binding of agonists and antagonists to AMPA receptors and provides clues for further drug discovery. PMID:24850223

Design of Stomach Acid-Stable and Mucin-Binding Enzyme Polymer Conjugates.

PubMed

Cummings, Chad S; Campbell, Alan S; Baker, Stefanie L; Carmali, Sheiliza; Murata, Hironobu; Russell, Alan J

2017-02-13

The reduced immunogenicity and increased stability of protein-polymer conjugates has made their use in therapeutic applications particularly attractive. However, the physicochemical interactions between polymer and protein, as well as the effect of this interaction on protein activity and stability, are still not fully understood. In this work, polymer-based protein engineering was used to examine the role of polymer physicochemical properties on the activity and stability of the chymotrypsin-polymer conjugates and their degree of binding to intestinal mucin. Four different chymotrypsin-polymer conjugates, each with the same polymer density, were synthesized using "grafting-from" atom transfer radical polymerization. The influence of polymer charge on chymotrypsin-polymer conjugate mucin binding, bioactivity, and stability in stomach acid was determined. Cationic polymers covalently attached to chymotrypsin showed high mucin binding, while zwitterionic, uncharged, and anionic polymers showed no mucin binding. Cationic polymers also increased chymotrypsin activity from pH 6-8, while zwitterionic polymers had no effect, and uncharged and anionic polymers decreased enzyme activity. Lastly, cationic polymers decreased the tendency of chymotrypsin to structurally unfold at extremely low pH, while uncharged and anionic polymers induced unfolding more quickly. We hypothesized that when polymers are covalently attached to the surface of a protein, the degree to which those polymers interact with the protein surface is the predominant determinant of whether the polymer will stabilize or inactivate the protein. Preferential interactions between the polymer and the protein lead to removal of water from the surface of the protein, and this, we believe, inactivates the enzyme.

Diffusion of uncharged probe reveals structural changes in polyacids initiated by their neutralization: poly(acrylic acids).

PubMed

Hyk, Wojciech; Masiak, Michal; Stojek, Zbigniew; Ciszkowska, Malgorzata

2005-03-17

The diffusion studies of the uncharged probe (1,1'-ferrocenedimethanol) have been successfully applied for the evaluation of the changes in the three-dimensional structure of poly(acrylic acids) of various molecular weights (ranging from 2000 to 4,000,000 g/mol) during their neutralization with a strong base. The qualitative picture of the macromolecule arrangement during the titration of the polyacids has been obtained from the conductometric measurements. The characteristic changes in the poly(acrylic acid) conductivity are practically the same for all polyacids examined and are in a very good agreement with the predictions of our theoretical model of the polyelectrolyte conductance. The transformation of the polyelectrolyte solution into the gel-like or gel phase has been investigated more quantitatively by tracing the changes in the diffusion coefficient of the uncharged probe redox system. The probe diffusivities, D, were determined using steady-state voltammetry at microelectrodes for a wide range of neutralization degree, alpha, of the polyacids tested. The dependencies of D versus alpha are of similar shape for all poly(acrylic acids). The first parts of the dependencies reflect a rapid increase in D (up to neutralization degree of either 45% for the lowest molecular-weight poly(acrylic acid) or 75-80% for other polyacids). They are followed by the parts of a slight drop in the diffusion coefficient. The changes in the probe diffusivity become stronger as the molecular weight of poly(acrylic acid) increases. The maximum probe diffusion coefficients are greater than the initial values in the pure polyacid solutions by 14, 24, 19, 30, and 28% for poly(acrylic acid) of molecular weights of 2000, 450,000, 1,250,000, 3,000,000, and 4,000,000 g/mol, respectively. The variation in the probe diffusion coefficient qualitatively follows the line of the changes in the macroscopic viscosity of the polyelectrolyte system. This is in contrast to the predictions of the Stokes-Einstein relation and, therefore, suggests that the changes in the probe diffusion rate are mainly due to the structural changes in the polyacrylate medium and the macromolecular rearrangements induced by the chemical, acid-base reaction. By adapting the obstruction model for diffusion in homogeneous gels, the transport characteristics of the probe were converted into the structural characteristics of the polyelectrolytic systems. It has been found that the most ordered structure of the polyelectrolyte, or in other words the most permeable structure, is obtained when poly(acrylic acid) is neutralized at 75-80%.

A non-catalytic histidine residue influences the function of the metalloprotease of Listeria monocytogenes.

PubMed

Forster, Brian M; Bitar, Alan Pavinski; Marquis, Hélène

2014-01-01

Mpl, a thermolysin-like metalloprotease, and PC-PLC, a phospholipase C, are synthesized as proenzymes by the intracellular bacterial pathogen Listeria monocytogenes. During intracellular growth, L. monocytogenes is temporarily confined in a membrane-bound vacuole whose acidification leads to Mpl autolysis and Mpl-mediated cleavage of the PC-PLC N-terminal propeptide. Mpl maturation also leads to the secretion of both Mpl and PC-PLC across the bacterial cell wall. Previously, we identified negatively charged and uncharged amino acid residues within the N terminus of the PC-PLC propeptide that influence the ability of Mpl to mediate the maturation of PC-PLC, suggesting that these residues promote the interaction of the PC-PLC propeptide with Mpl. In the present study, we identified a non-catalytic histidine residue (H226) that influences Mpl secretion across the cell wall and its ability to process PC-PLC. Our results suggest that a positive charge at position 226 is required for Mpl functions other than autolysis. Based on the charge requirement at this position, we hypothesize that this residue contributes to the interaction of Mpl with the PC-PLC propeptide.

Developing hybrid approaches to predict pKa values of ionizable groups

PubMed Central

Witham, Shawn; Talley, Kemper; Wang, Lin; Zhang, Zhe; Sarkar, Subhra; Gao, Daquan; Yang, Wei

2011-01-01

Accurate predictions of pKa values of titratable groups require taking into account all relevant processes associated with the ionization/deionization. Frequently, however, the ionization does not involve significant structural changes and the dominating effects are purely electrostatic in origin allowing accurate predictions to be made based on the electrostatic energy difference between ionized and neutral forms alone using a static structure. On another hand, if the change of the charge state is accompanied by a structural reorganization of the target protein, then the relevant conformational changes have to be taken into account in the pKa calculations. Here we report a hybrid approach that first predicts the titratable groups, which ionization is expected to cause conformational changes, termed “problematic” residues, then applies a special protocol on them, while the rest of the pKa’s are predicted with rigid backbone approach as implemented in multi-conformation continuum electrostatics (MCCE) method. The backbone representative conformations for “problematic” groups are generated with either molecular dynamics simulations with charged and uncharged amino acid or with ab-initio local segment modeling. The corresponding ensembles are then used to calculate the pKa of the “problematic” residues and then the results are averaged. PMID:21744395

T box riboswitches in Actinobacteria: Translational regulation via novel tRNA interactions

PubMed Central

Sherwood, Anna V.; Grundy, Frank J.; Henkin, Tina M.

2015-01-01

The T box riboswitch regulates many amino acid-related genes in Gram-positive bacteria. T box riboswitch-mediated gene regulation was shown previously to occur at the level of transcription attenuation via structural rearrangements in the 5′ untranslated (leader) region of the mRNA in response to binding of a specific uncharged tRNA. In this study, a novel group of isoleucyl-tRNA synthetase gene (ileS) T box leader sequences found in organisms of the phylum Actinobacteria was investigated. The Stem I domains of these RNAs lack several highly conserved elements that are essential for interaction with the tRNA ligand in other T box RNAs. Many of these RNAs were predicted to regulate gene expression at the level of translation initiation through tRNA-dependent stabilization of a helix that sequesters a sequence complementary to the Shine–Dalgarno (SD) sequence, thus freeing the SD sequence for ribosome binding and translation initiation. We demonstrated specific binding to the cognate tRNAIle and tRNAIle-dependent structural rearrangements consistent with regulation at the level of translation initiation, providing the first biochemical demonstration, to our knowledge, of translational regulation in a T box riboswitch. PMID:25583497

Prediction of selectivity for enantiomeric separations of uncharged compounds by capillary electrophoresis involving dual cyclodextrin systems.

PubMed

Abushoffa, Adel M; Fillet, Marianne; Hubert, Phillipe; Crommen, Jacques

2002-03-01

The single-isomer polyanionic cyclodextrin (CD) derivative heptakis-6-sulfato-beta-cyclodextrin (HSbetaCD) has been tested as chiral additive for the enantioseparation of non-steroidal anti-inflammatory drugs, such as fenoprofen, flurbiprofen, ibuprofen and ketoprofen, in capillary electrophoresis, using a pH 2.5 phosphoric acid-triethanolamine buffer in the reversed polarity mode. In most cases, the enantiomers of these acidic compounds, present in uncharged form at that pH, were only poorly resolved with HSbetaCD alone. However, the use of HSbetaCD in combination with the neutral CD derivative, heptakis-(2,3,6-tri-O-methyl)-beta-cyclodextrin (TMbetaCD), which has a particularly high enantioselectivity towards these compounds, has led to complete enantioresolution in reasonably low migration times in most cases. Affinity constants for the enantiomers with the two cyclodextrins were determined, using linear regression in a two-step approach. Affinity constants with the charged HSbetaCD were first calculated in single systems while those with the neutral TMbetaCD were determined in dual systems. Selectivity for the enantiomeric separation of these compounds in dual CD systems could be predicted using recently developed mathematical models.

Partial nucleotide sequences, and routine typing by polymerase chain reaction-restriction fragment length polymorphism, of the brown trout (Salmo trutta) lactate dehydrogenase, LDH-C1*90 and *100 alleles.

PubMed

McMeel, O M; Hoey, E M; Ferguson, A

2001-01-01

The cDNA nucleotide sequences of the lactate dehydrogenase alleles LDH-C1*90 and *100 of brown trout (Salmo trutta) were found to differ at position 308 where an A is present in the *100 allele but a G is present in the *90 allele. This base substitution results in an amino acid change from aspartic acid at position 82 in the LDH-C1 100 allozyme to a glycine in the 90 allozyme. Since aspartic acid has a net negative charge whilst glycine is uncharged, this is consistent with the electrophoretic observation that the LDH-C1 100 allozyme has a more anodal mobility relative to the LDH-C1 90 allozyme. Based on alignment of the cDNA sequence with the mouse genomic sequence, a local primer set was designed, incorporating the variable position, and was found to give very good amplification with brown trout genomic DNA. Sequencing of this fragment confirmed the difference in both homozygous and heterozygous individuals. Digestion of the polymerase chain reaction products with BslI, a restriction enzyme specific for the site difference, gave one, two and three fragments for the two homozygotes and the heterozygote, respectively, following electrophoretic separation. This provides a DNA-based means of routine screening of the highly informative LDH-C1* polymorphism in brown trout population genetic studies. Primer sets presented could be used to sequence cDNA of other LDH* genes of brown trout and other species.

[New aspects of the molecular effect of anti-arrhythmia agents].

PubMed

Honerjäger, P

1990-04-01

Excitation propagation is mediated by the brief opening of voltage-dependent Na-channels in the plasma membranes of cells of the conduction system and working myocardium. The refractory period is a function of the re-availability of the Na-channel for renewed opening. Most antiarrhythmic agents block cardiac Na-channels and, consequently, affect the desired refractory period prolongation. At the same time, however, dependent on the concentration and the substance, they slow conduction; an effect which can facilitate reentry excitation in the injured heart. The Na-channel blocking drugs, class I antiarrhythmic agents, are distinguished from the beta-receptor blockers, class II, repolarizing prolonging drugs, class III, and the cardiac Ca-channel blocking drugs (class IV) (Table 1). MOLECULAR STRUCTURE OF THE CARDIAC NA-CHANNEL: Voltage-dependent Na-channels which have been structurally elucidated to date are glycoprotein macromolecules of about 2000 amino acids with a molecular weight of about 260,000. Beginning at the amino terminal, four consecutive homologous domains can be differentiated which are composed of six transmembranous segments each. The terminal portion of the chain as well as the connecting segments between the domains appear intracellular. There are important relationships between the molecular structure and the function of the Na-channel (Figure 1). On comparison of the primary structures of neuronal and cardiac Na-channels, domains I to IV as well as the connecting segment between domains III and IV, are nearly identical. Homology in all of the remaining molecular regions, in contrast, is less than 70%. These segments as well as the differing structure of the four S5-S6 connecting chains may be responsible for the varying functional response of the cardiac Na-channels. MOLECULAR SITE OF ACTION OF ANTIARRHYTHMIC AGENTS AT THE CARDIAC NA-CHANNEL: Since most antiarrhythmic agents are weak bases with pK values between 7.5 and 9.5, in the physiologic range of pH, they are present in part in the protonated, positively-charged form, in part as uncharged free base. It is assumed that the Na-channel of nerve and skeletal muscle has one receptor for local anesthetics at which both the protonated and the uncharged molecular forms bind. The receptor is thought to be located on the inner wall of the ion pore about half of the distance between the intracellular and the extracellular channel opening. The uncharged form of the Na-channel blocker penetrates directly from the lipid phase of the surrounding cell membrane, the protonated form only from the intracellular space during the short opening of the channel at the beginning of the action potential. Through binding on the receptor, the Na-channel is blocked. Dissociation of the molecular forms takes place in the same manner. The peptide region on which antiarrhythmic drugs bind, however, has not been identified. By means of the patch-clamp technique, it has been shown that on extracellular application of the quaternary lidocaine derivative QX-314 there is a rapid and marked reduction of Na-flux in cardiac Purkinje fibers in contrast to the effects at neuronal and skeletal muscle Na-channels. Intracellular application similarly leads to blockade but only in the course of repetitive depolarizations indicating that the cardiac Na-channel may have a second binding site for local anesthetics at the extracellular side.(ABSTRACT TRUNCATED AT 400 WORDS)

Evolutionarily conserved IMPACT impairs various stress responses that require GCN1 for activating the eIF2 kinase GCN2

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

Cambiaghi, Tavane D.; Pereira, Catia M.; Shanmugam, Renuka

2014-01-10

Highlights: •GCN1 is required for mammalian and yeast GCN2 function in a variety of conditions. •Mammalian IMPACT competes with GCN2 for GCN1 binding. •IMPACT and its yeast counterpart YIH1 downregulate GCN1-dependent GCN2 activation. -- Abstract: In response to a range of environmental stresses, phosphorylation of the alpha subunit of the translation initiation factor 2 (eIF2α) represses general protein synthesis coincident with increased translation of specific mRNAs, such as those encoding the transcription activators GCN4 and ATF4. The eIF2α kinase GCN2 is activated by amino acid starvation by a mechanism involving GCN2 binding to an activator protein GCN1, along with associationmore » with uncharged tRNA that accumulates during nutrient deprivation. We previously showed that mammalian IMPACT and its yeast ortholog YIH1 bind to GCN1, thereby preventing GCN1 association with GCN2 and stimulation of this eIF2α kinase during amino acid depletion. GCN2 activity is also enhanced by other stresses, including proteasome inhibition, UV irradiation and lack of glucose. Here, we provide evidence that IMPACT affects directly and specifically the activation of GCN2 under these stress conditions in mammalian cells. We show that activation of mammalian GCN2 requires its interaction with GCN1 and that IMPACT promotes the dissolution of the GCN2–GCN1 complex. To a similar extent as the overexpression of YIH1, overexpression of IMPACT in yeast cells inhibited growth under all stress conditions that require GCN2 and GCN1 for cell survival, including exposure to acetic acid, high levels of NaCl, H{sub 2}O{sub 2} or benomyl. This study extends our understanding of the roles played by GCN1 in GCN2 activation induced by a variety of stress arrangements and suggests that IMPACT and YIH1 use similar mechanisms for regulating this eIF2α kinase.« less

Born energy, acid-base equilibrium, structure and interactions of end-grafted weak polyelectrolyte layers.

PubMed

Nap, R J; Tagliazucchi, M; Szleifer, I

2014-01-14

This work addresses the effect of the Born self-energy contribution in the modeling of the structural and thermodynamical properties of weak polyelectrolytes confined to planar and curved surfaces. The theoretical framework is based on a theory that explicitly includes the conformations, size, shape, and charge distribution of all molecular species and considers the acid-base equilibrium of the weak polyelectrolyte. Namely, the degree of charge in the polymers is not imposed but it is a local varying property that results from the minimization of the total free energy. Inclusion of the dielectric properties of the polyelectrolyte is important as the environment of a polymer layer is very different from that in the adjacent aqueous solution. The main effect of the Born energy contribution on the molecular organization of an end-grafted weak polyacid layer is uncharging the weak acid (or basic) groups and consequently decreasing the concentration of mobile ions within the layer. The magnitude of the effect increases with polymer density and, in the case of the average degree of charge, it is qualitatively equivalent to a small shift in the equilibrium constant for the acid-base equilibrium of the weak polyelectrolyte monomers. The degree of charge is established by the competition between electrostatic interactions, the polymer conformational entropy, the excluded volume interactions, the translational entropy of the counterions and the acid-base chemical equilibrium. Consideration of the Born energy introduces an additional energetic penalty to the presence of charged groups in the polyelectrolyte layer, whose effect is mitigated by down-regulating the amount of charge, i.e., by shifting the local-acid base equilibrium towards its uncharged state. Shifting of the local acid-base equilibrium and its effect on the properties of the polyelectrolyte layer, without considering the Born energy, have been theoretically predicted previously. Account of the Born energy leads to systematic, but in general small, corrections to earlier theoretical predictions describing the behavior of weak polyelectrolyte layers. However, polyelectrolyte uncharging results in a decrease in the concentration of counterions and inclusion of the Born Energy can result in a substantial decrease of the counterion concentration. The effect of considering the Born energy contribution is explored for end-grafted weak polyelectrolyte layers by calculating experimental observables which are known to depend on the presence of charges within the polyelectrolyte layer: inclusion of the Born energy contribution leads to a decrease in the capacitance of polyelectrolyte-modified electrodes, a decrease of conductivity of polyelectrolyte-modified nanopores and an increase in the repulsion exerted by a planar polyelectrolyte layer confined by an opposing wall.

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

Phthalocyanine-Peptide Conjugates for Epidermal Growth Factor Receptor Targeting1

PubMed Central

Ongarora, Benson G.; Fontenot, Krystal R.; Hu, Xiaoke; Sehgal, Inder; Satyanarayana-Jois, Seetharama D.; Vicente, M. Graça H.

2012-01-01

Four phthalocyanine (Pc)-peptide conjugates designed to target the epidermal growth factor receptor (EGFR) were synthesized and evaluated in vitro using four cell lines: human carcinoma A431 and HEp2, human colorectal HT-29, and kidney Vero (negative control) cells. Two peptide ligands for EGFR were investigated: EGFR-L1 and -L2, bearing 6 and 13 amino acid residues, respectively. The peptides and Pc-conjugates were shown to bind to EGFR using both theoretical (Autodock) and experimental (SPR) investigations. The Pc-EGFR-L1 conjugates 5a and 5b efficiently targeted EGFR and were internalized, in part due to their cationic charge, whereas the uncharged Pc-EGFR-L2 conjugates 4b and 6a poorly targeted EGFR maybe due to their low aqueous solubility. All conjugates were non-toxic (IC50 > 100 µM) to HT-29 cells, both in the dark and upon light activation (1 J/cm2). Intravenous (iv) administration of conjugate 5b into nude mice bearing A431 and HT-29 human tumor xenografts resulted in a near-IR fluorescence signal at ca. 700 nm, 24 h after administration. Our studies show that Pc-EGFR-L1 conjugates are promising near-IR fluorescent contrast agents for CRC, and potentially other EGFR over-expressing cancers. PMID:22468711

Peptide probes reveal a hydrophobic steric ratchet in the anthrax toxin protective antigen translocase

PubMed Central

Colby, Jennifer M.; Krantz, Bryan A.

2015-01-01

Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin's protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor (LF) and edema factor (EF), into the host cytosol under the proton motive force (PMF). Protein translocation under a PMF is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between LF amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides; and while these steric interactions may make a peptide translocate poorly, in the context of folded domains they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism. PMID:26363343

Biomimetic nanoparticles with polynucleotide and PEG mixed-monolayers enhance calcium phosphate mineralization

NASA Astrophysics Data System (ADS)

Vasconcellos, Kayla B.; McHugh, Sean M.; Dapsis, Katherine J.; Petty, Alexander R.; Gerdon, Aren E.

2013-09-01

Biomineralization of hydroxyapatite (Ca10(PO4)6(OH)2) is of significant importance in biomedical applications such as bone and dental repair, and biomimetic control of mineral formation may lead to more effective restorative procedures. Gold nanoparticles are functional scaffolds on which to assemble multi-component monolayers capable of mimicking protein activity in the templated synthesis of calcium phosphate. The goal of this research was to explore nanoparticle templates with mixed-monolayers of uncharged polar polyethylene glycol (PEG) molecules and highly charged polynucleotide and amino acid molecules in their ability to influence mineralization rates and mineral particle size and morphology. This research demonstrates through time-resolved optical density and dynamic light scattering measurements that the combination of tiopronin, PEG, and DNA presented on a nanoparticle surface decreases nanoparticle aggregation from 59 to 21 nm solvated radius, increases mineralization kinetics from 1.5 × 10-3 to 3.1 × 10-3 OD/min, and decreases mineral particle size from 685 to 442 nm average radius. FT-IR and TEM data demonstrate that mineralized material, while initially amorphous, transforms to a semi-crystalline material when guided by template interactions. This demonstrates that surface-tailored monolayer protected cluster scaffolds are successful and controllable mineralization templates with further potential for biomedical applications involving calcium phosphate and other biomaterials.

Metabolic engineering of the shikimate pathway

DOEpatents

Juminaga, Darmawi; Keasling, Jay D.

2017-01-10

The present disclosure relates to engineered microorganisms that produce amino acids and amino acid intermediates. In particular, the disclosure relates to recombinant nucleic acids encoding operons that increase production of aromatic amino acids and the aromatic amino acid intermediate shikimate; microorganisms with increased production of aromatic amino acids and the aromatic amino acid intermediate shikimate; and methods related to the production of aromatic amino acids, the aromatic amino acid intermediate shikimate, and commodity chemicals derived therefrom.

Identification and Analysis of Novel Amino-Acid Sequence Repeats in Bacillus anthracis str. Ames Proteome Using Computational Tools

PubMed Central

Hemalatha, G. R.; Rao, D. Satyanarayana; Guruprasad, L.

2007-01-01

We have identified four repeats and ten domains that are novel in proteins encoded by the Bacillus anthracis str. Ames proteome using automated in silico methods. A “repeat” corresponds to a region comprising less than 55-amino-acid residues that occur more than once in the protein sequence and sometimes present in tandem. A “domain” corresponds to a conserved region with greater than 55-amino-acid residues and may be present as single or multiple copies in the protein sequence. These correspond to (1) 57-amino-acid-residue PxV domain, (2) 122-amino-acid-residue FxF domain, (3) 111-amino-acid-residue YEFF domain, (4) 109-amino-acid-residue IMxxH domain, (5) 103-amino-acid-residue VxxT domain, (6) 84-amino-acid-residue ExW domain, (7) 104-amino-acid-residue NTGFIG domain, (8) 36-amino-acid-residue NxGK repeat, (9) 95-amino-acid-residue VYV domain, (10) 75-amino-acid-residue KEWE domain, (11) 59-amino-acid-residue AFL domain, (12) 53-amino-acid-residue RIDVK repeat, (13) (a) 41-amino-acid-residue AGQF repeat and (b) 42-amino-acid-residue GSAL repeat. A repeat or domain type is characterized by specific conserved sequence motifs. We discuss the presence of these repeats and domains in proteins from other genomes and their probable secondary structure. PMID:17538688

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.

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.

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

PubMed

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

2016-01-01

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

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

PubMed Central

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

2016-01-01

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

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

Distribution, industrial applications, and enzymatic synthesis of D-amino acids.

PubMed

Gao, Xiuzhen; Ma, Qinyuan; Zhu, Hailiang

2015-04-01

D-Amino acids exist widely in microbes, plants, animals, and food and can be applied in pharmaceutical, food, and cosmetics. Because of their widespread applications in industry, D-amino acids have recently received more and more attention. Enzymes including D-hydantoinase, N-acyl-D-amino acid amidohydrolase, D-amino acid amidase, D-aminopeptidase, D-peptidase, L-amino acid oxidase, D-amino acid aminotransferase, and D-amino acid dehydrogenase can be used for D-amino acids synthesis by kinetic resolution or asymmetric amination. In this review, the distribution, industrial applications, and enzymatic synthesis methods are summarized. And, among all the current enzymatic methods, D-amino acid dehydrogenase method not only produces D-amino acid by a one-step reaction but also takes environment and atom economics into consideration; therefore, it is deserved to be paid more attention.

Acidic and uncharged polar residues in the consensus motifs of the yeast Ca2+ transporter Gdt1p are required for calcium transport.

PubMed

Colinet, Anne-Sophie; Thines, Louise; Deschamps, Antoine; Flémal, Gaëlle; Demaegd, Didier; Morsomme, Pierre

2017-07-01

The UPF0016 family is a recently identified group of poorly characterized membrane proteins whose function is conserved through evolution and that are defined by the presence of 1 or 2 copies of the E-φ-G-D-[KR]-[TS] consensus motif in their transmembrane domain. We showed that 2 members of this family, the human TMEM165 and the budding yeast Gdt1p, are functionally related and are likely to form a new group of Ca 2+ transporters. Mutations in TMEM165 have been demonstrated to cause a new type of rare human genetic diseases denominated as Congenital Disorders of Glycosylation. Using site-directed mutagenesis, we generated 17 mutations in the yeast Golgi-localized Ca 2+ transporter Gdt1p. Single alanine substitutions were targeted to the highly conserved consensus motifs, 4 acidic residues localized in the central cytosolic loop, and the arginine at position 71. The mutants were screened in a yeast strain devoid of both the endogenous Gdt1p exchanger and Pmr1p, the Ca 2+ -ATPase of the Golgi apparatus. We show here that acidic and polar uncharged residues of the consensus motifs play a crucial role in calcium tolerance and calcium transport activity and are therefore likely to be architectural components of the cation binding site of Gdt1p. Importantly, we confirm the essential role of the E53 residue whose mutation in humans triggers congenital disorders of glycosylation. © 2017 John Wiley & Sons Ltd.

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.

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.

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.

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.

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.

Codes in the codons: construction of a codon/amino acid periodic table and a study of the nature of specific nucleic acid-protein interactions.

PubMed

Benyo, B; Biro, J C; Benyo, Z

2004-01-01

The theory of "codon-amino acid coevolution" was first proposed by Woese in 1967. It suggests that there is a stereochemical matching - that is, affinity - between amino acids and certain of the base triplet sequences that code for those amino acids. We have constructed a common periodic table of codons and amino acids, where the nucleic acid table showed perfect axial symmetry for codons and the corresponding amino acid table also displayed periodicity regarding the biochemical properties (charge and hydrophobicity) of the 20 amino acids and the position of the stop signals. The table indicates that the middle (2/sup nd/) amino acid in the codon has a prominent role in determining some of the structural features of the amino acids. The possibility that physical contact between codons and amino acids might exist was tested on restriction enzymes. Many recognition site-like sequences were found in the coding sequences of these enzymes and as many as 73 examples of codon-amino acid co-location were observed in the 7 known 3D structures (December 2003) of endonuclease-nucleic acid complexes. These results indicate that the smallest possible units of specific nucleic acid-protein interaction are indeed the stereochemically compatible codons and amino acids.

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.

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.

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

PubMed

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

2015-03-21

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

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

PubMed Central

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

2017-01-01

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

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

PubMed

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

2017-01-11

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

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.

Effect of a protein-rich meal on urinary and salivary free amino acid concentrations in human subjects.

PubMed

Brand, H S; Jörning, G G; Chamuleau, R A; Abraham-Inpijn, L

1997-08-08

The aim of the present study was to investigate whether in healthy volunteers acute changes in plasma free amino acid composition after a protein-rich test meal are reflected in the urinary and salivary concentrations of the corresponding amino acids. The ingestion of a protein-rich meal elicited a significant increase of plasma and urine amino acid concentrations. The postprandial salivary amino acid excretion showed only minor changes. For several amino acids (alanine, arginine, asparagine, glycine, threonine and valine) significant relations were observed between the increase in concentration of these amino acids in venous plasma and urine. In whole saliva, only threonine and valine showed a significant relationship with the corresponding plasma concentration. Our data suggest that the urinary amino acid excretion of several amino acids has the potential for estimating short-term changes in plasma concentrations. Determination of salivary amino acid concentrations seems less appropriate for this purpose.

'Trophic' and 'source' amino acids in trophic estimation: a likely metabolic explanation.

PubMed

O'Connell, T C

2017-06-01

Amino acid nitrogen isotopic analysis is a relatively new method for estimating trophic position. It uses the isotopic difference between an individual's 'trophic' and 'source' amino acids to determine its trophic position. So far, there is no accepted explanation for the mechanism by which the isotopic signals in 'trophic' and 'source' amino acids arise. Yet without a metabolic understanding, the utility of nitrogen isotopic analyses as a method for probing trophic relations, at either bulk tissue or amino acid level, is limited. I draw on isotopic tracer studies of protein metabolism, together with a consideration of amino acid metabolic pathways, to suggest that the 'trophic'/'source' groupings have a fundamental metabolic origin, to do with the cycling of amino-nitrogen between amino acids. 'Trophic' amino acids are those whose amino-nitrogens are interchangeable, part of a metabolic amino-nitrogen pool, and 'source' amino acids are those whose amino-nitrogens are not interchangeable with the metabolic pool. Nitrogen isotopic values of 'trophic' amino acids will reflect an averaged isotopic signal of all such dietary amino acids, offset by the integrated effect of isotopic fractionation from nitrogen cycling, and modulated by metabolic and physiological effects. Isotopic values of 'source' amino acids will be more closely linked to those of equivalent dietary amino acids, but also modulated by metabolism and physiology. The complexity of nitrogen cycling suggests that a single identifiable value for 'trophic discrimination factors' is unlikely to exist. Greater consideration of physiology and metabolism should help in better understanding observed patterns in nitrogen isotopic values.

The Next Generation MOD: A Microchip Amino Acid Analyzer for Detecting Extraterrestrial Life

NASA Technical Reports Server (NTRS)

Mathies, R. A.; Hutt, L. D.; Bada, J. L.; Glavin, D.; Grunthaner, F. J.; Grunthaner, P. J.

2000-01-01

The MOD (Mars Organic Detector) instrument which has selected for the definition phase of the BEDS package on the 2005 Mars Explorer Program spacecraft is designed to simply detect the presence of amino acids in Martian surface samples at a sensitivity of a few parts per billion (ppb). An additional important aspect of amino acid analyses of Martian samples is identifying and quantifying which compounds are present, and also distinguishing those produced abiotically from those synthesized by either extinct or extant life. Amino acid homochirality provides an unambiguous way of distinguishing between abiotic vs. biotic origins. Proteins made up of mixed D- and L-amino acids would not likely have been efficient catalysts in early organisms because they could not fold into bioactive configurations such as the a-helix. However, enzymes made up of all D-amino acids function just as well as those made up of only L-amino acids, but the two enzymes use the opposite stereoisomeric substrates. There are no biochemical reasons why L-amino acids would be favored over Damino acids. On Earth, the use of only L-amino acids in proteins by life is probably simply a matter of chance. We assume that if proteins and enzymes were a component of extinct or extant life on Mars, then amino acid homochirality would have been a requirement. However, the possibility that Martian life was (or is) based on D-amino acids would be equal to that based on L-amino acids. The detection of a nonracemic mixture of amino acids in a Martian sample would be strong evidence for the presence of an extinct or extant biota on Mars. The finding of an excess of D-amino acids would provide irrefutable evidence of unique Martian life that could not have been derived from seeding the planet with terrestrial life (or the seeding of the Earth with Martian life). In contrast, the presence of racemic amino acids, along with non-protein amino acids such as alpha-aminoisobutyric acid and isovaline, would be indicative of an abiotic origin, although we have to consider the possibility that the racemic amino acids were generated from the racemization of biotically produced amino acids.

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

PubMed

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

2014-09-01

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

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.

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.

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

PubMed

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

2014-01-01

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

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.

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.

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

Metabolomics method to comprehensively analyze amino acids in different domains.

PubMed

Gu, Haiwei; Du, Jianhai; Carnevale Neto, Fausto; Carroll, Patrick A; Turner, Sally J; Chiorean, E Gabriela; Eisenman, Robert N; Raftery, Daniel

2015-04-21

Amino acids play essential roles in both metabolism and the proteome. Many studies have profiled free amino acids (FAAs) or proteins; however, few have connected the measurement of FAA with individual amino acids in the proteome. In this study, we developed a metabolomics method to comprehensively analyze amino acids in different domains, using two examples of different sample types and disease models. We first examined the responses of FAAs and insoluble-proteome amino acids (IPAAs) to the Myc oncogene in Tet21N human neuroblastoma cells. The metabolic and proteomic amino acid profiles were quite different, even under the same Myc condition, and their combination provided a better understanding of the biological status. In addition, amino acids were measured in 3 domains (FAAs, free and soluble-proteome amino acids (FSPAAs), and IPAAs) to study changes in serum amino acid profiles related to colon cancer. A penalized logistic regression model based on the amino acids from the three domains had better sensitivity and specificity than that from each individual domain. To the best of our knowledge, this is the first study to perform a combined analysis of amino acids in different domains, and indicates the useful biological information available from a metabolomics analysis of the protein pellet. This study lays the foundation for further quantitative tracking of the distribution of amino acids in different domains, with opportunities for better diagnosis and mechanistic studies of various diseases.

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.

Experiments of the Essential Amino Acids at high temperature and high pressure using DAC

NASA Astrophysics Data System (ADS)

Kubo, K.; Okamoto, K.

2017-12-01

Amino acids are organic compounds that form the fundamental part of life. Proteins are formed by peptide binding and polymerization of amino acids. Amino acids are polymerized in the ridge hydrothermal field, formed proteins, and might be evolved into life. Experimental studies on the polymerization of amino acids in hydrothermal environments have been conducted. However, they were hydrothermal experiments and after the experiments. All run products (amid-acids) were observed at ambient condition. Few in-situ observations of amino acids were done in experiments in hydrothermal condition. In order to perform in-situ observation of the polymerization of amino acids, we have conducted the DAC experiments. Amino acids were filled in the DAC, pressures were applied, then heated to high temperature with Raman analysis. In preliminary experiment using glycine, polymerization forming diglycine, were completed. Investigation amino acids polymerization under hydrothermal condition would shed light for new view of early life science.

Reasons for the occurrence of the twenty coded protein amino acids

NASA Technical Reports Server (NTRS)

Weber, A. L.; Miller, S. L.

1981-01-01

Factors involved in the selection of the 20 protein L-alpha-amino acids during chemical evolution and the early stages of Darwinian evolution are discussed. The selection is considered on the basis of the availability in the primitive ocean, function in proteins, the stability of the amino acid and its peptides, stability to racemization, and stability on the transfer RNA. It is concluded that aspartic acid, glutamic acid, arginine, lysine, serine and possibly threonine are the best choices for acidic, basic and hydroxy amino acids. The hydrophobic amino acids are reasonable choices, except for the puzzling absences of alpha-amino-n-butyric acid, norvaline and norleucine. The choices of the sulfur and aromatic amino acids seem reasonable, but are not compelling. Asparagine and glutamine are apparently not primitive. If life were to arise on another planet, it would be expected that the catalysts would be poly-alpha-amino acids and that about 75% of the amino acids would be the same as on the earth.

The role of amino acid profiles in diabetes risk assessment.

PubMed

Nagao, Kenji; Yamakado, Minoru

2016-07-01

The concentrations of plasma-free amino acids, such as branched-chain amino acids and aromatic amino acids, are associated with visceral obesity, insulin resistance, and the future development of diabetes and cardiovascular diseases. This review discusses recent progress in the early assessment of the risk of developing diabetes and the reversal of altered plasma-free amino acids through interventions. Additionally, recent developments that have increased the utility of amino acid profiling technology are also described. Plasma-free amino acid alterations in the early stage of lifestyle-related diseases are because of obesity and insulin resistance-related inflammation, and these alterations are reversed by appropriate (nutritional, drug, or surgical) interventions that improve insulin sensitivity. For clinical applications, procedures for measuring amino acids are being standardized and automated. Plasma-free amino acid profiles have potential as biomarkers for both assessing diabetes risk and monitoring the effects of strategies designed to lower that risk. In addition, the methodology for measuring amino acids has been refined, with the goal of routine clinical application.

Changes in the free amino acid composition with maturity of the noble cultivar of Vitis rotundifolia Michx. grape.

PubMed

Lamikanra, O; Kassa, A K

1999-12-01

The changes in amino acid composition that occur with maturity of the Noble cultivar of the Vitis rotundifolia Michx. (muscadine) grape were determined by HPLC. Eighteen amino acids were identified. Histidine was the most prominent amino acid followed by alanine. The concentrations of most of the major amino acids (alanine, glycine, histidine, valine, isoleucine, aspartic acid, and serine) were highest at verasion. Glutamine and threonine contents dropped sharply after fruit set, while those of arginine and proline increased gradually with maturity and ripening. Tyrosine content increased gradually with maturity and ripening following a slight drop after fruit set. In ripe grapes, seeds contained most of the amino acids in mature grapes (50%) followed by the pulp (23%), the juice (15%), and the skin (11%). Alanine, histidine, and arginine were the principal amino acids identified in the juice. Alanine, histidine, arginine, valine, glutamine, aspartic acid, proline, serine, and threonine accounted for about 90% of the amino acids in the pulp. In seeds, alanine, proline, asparagine, and histidine accounted for over 55% of the amino acids, while alanine and histidine were found to be the predominant free amino acids in the skin. The profile indicates some differences in the changes in amino acid composition with berry maturity and relative amounts of amino acids present in muscadine compared to those in nonmuscadine grape species.

Amino Acid Flux from Metabolic Network Benefits Protein Translation: the Role of Resource Availability.

PubMed

Hu, Xiao-Pan; Yang, Yi; Ma, Bin-Guang

2015-06-09

Protein translation is a central step in gene expression and affected by many factors such as codon usage bias, mRNA folding energy and tRNA abundance. Despite intensive previous studies, how metabolic amino acid supply correlates with protein translation efficiency remains unknown. In this work, we estimated the amino acid flux from metabolic network for each protein in Escherichia coli and Saccharomyces cerevisiae by using Flux Balance Analysis. Integrated with the mRNA expression level, protein abundance and ribosome profiling data, we provided a detailed description of the role of amino acid supply in protein translation. Our results showed that amino acid supply positively correlates with translation efficiency and ribosome density. Moreover, with the rank-based regression model, we found that metabolic amino acid supply facilitates ribosome utilization. Based on the fact that the ribosome density change of well-amino-acid-supplied genes is smaller than poorly-amino-acid-supply genes under amino acid starvation, we reached the conclusion that amino acid supply may buffer ribosome density change against amino acid starvation and benefit maintaining a relatively stable translation environment. Our work provided new insights into the connection between metabolic amino acid supply and protein translation process by revealing a new regulation strategy that is dependent on resource availability.

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.

Expression pattern of peptide and amino acid genes in digestive tract of transporter juvenile turbot ( Scophthalmus maximus L.)

NASA Astrophysics Data System (ADS)

Xu, Dandan; He, Gen; Mai, Kangsen; Zhou, Huihui; Xu, Wei; Song, Fei

2016-04-01

Turbot ( Scophthalmus maximus L.), a carnivorous fish species with high dietary protein requirement, was chosen to examine the expression pattern of peptide and amino acid transporter genes along its digestive tract which was divided into six segments including stomach, pyloric caeca, rectum, and three equal parts of the remainder of the intestine. The results showed that the expression of two peptide and eleven amino acid transporters genes exhibited distinct patterns. Peptide transporter 1 (PepT1) was rich in proximal intestine while peptide transporter 2 (PepT2) was abundant in distal intestine. A number of neutral and cationic amino acid transporters expressed richly in whole intestine including B0-type amino acid transporter 1 (B0AT1), L-type amino acid transporter 2 (LAT2), T-type amino acid transporter 1 (TAT1), proton-coupled amino acid transporter 1 (PAT1), y+L-type amino acid transporter 1 (y+LAT1), and cationic amino acid transporter 2 (CAT2) while ASC amino acid transporter 2 (ASCT2), sodium-coupled neutral amino acid transporter 2 (SNAT2), and y+L-type amino acid transporter 2 (y+LAT2) abundantly expressed in stomach. In addition, system b0,+ transporters (rBAT and b0,+AT) existed richly in distal intestine. These findings comprehensively characterized the distribution of solute carrier family proteins, which revealed the relative importance of peptide and amino acid absorption through luminal membrane. Our findings are helpful to understand the mechanism of the utilization of dietary protein in fish with a short digestive tract.

Electrostatic application of antimicrobial sprays to sanitize food handling and processing surfaces for enhanced food safety

NASA Astrophysics Data System (ADS)

Lyons, Shawn M.; Harrison, Mark A.; Law, S. Edward

2011-06-01

Human illnesses and deaths caused by foodborne pathogens (e.g., Salmonella enterica, Listeria monocytogenes, Escherichia coli O157:H7, etc.) are of increasing concern globally in maintaining safe food supplies. At various stages of the food production, processing and supply chain antimicrobial agents are required to sanitize contact surfaces. Additionally, during outbreaks of contagious pathogenic microorganisms (e.g., H1N1 influenza), public health requires timely decontamination of extensive surfaces within public schools, mass transit systems, etc. Prior publications verify effectiveness of air-assisted, induction-charged (AAIC) electrostatic spraying of various chemical and biological agents to protect on-farm production of food crops...typically doubling droplet deposition efficiency with concomitant increases in biological control efficacy. Within a biosafety facility this present work evaluated the AAIC electrostatic-spraying process for application of antimicrobial liquids onto various pathogen-inoculated food processing and handling surfaces as a food safety intervention strategy. Fluoroanalysis of AAIC electrostatic sprays (-7.2 mC/kg charge-to-mass ratio) showed significantly greater (p<0.05) mass of tracer active ingredient (A.I.) deposited onto target surfaces at various orientations as compared both to a similar uncharged spray nozzle (0 mC/kg) and to a conventional hydraulic-atomizing nozzle. Per unit mass of A.I. dispensed toward targets, for example, A.I. mass deposited by AAIC electrostatic sprays onto difficult to coat backsides was 6.1-times greater than for similar uncharged sprays and 29.0-times greater than for conventional hydraulic-nozzle sprays. Even at the 56% reduction in peracetic acid sanitizer A.I. dispensed by AAIC electrostatic spray applications, they achieved equal or greater CFU population reductions of Salmonella on most target orientations and materials as compared to uncharged sprays and conventional full-rate hydraulic-nozzle sprays.

Block of Brain Sodium Channels by Peptide Mimetics of the Isoleucine, Phenylalanine, and Methionine (IFM) Motif from the Inactivation Gate

PubMed Central

Eaholtz, Galen; Colvin, Anita; Leonard, Daniele; Taylor, Charles; Catterall, William A.

1999-01-01

Inactivation of sodium channels is thought to be mediated by an inactivation gate formed by the intracellular loop connecting domains III and IV. A hydrophobic motif containing the amino acid sequence isoleucine, phenylalanine, and methionine (IFM) is required for the inactivation process. Peptides containing the IFM motif, when applied to the cytoplasmic side of these channels, produce two types of block: fast block, which resembles the inactivation process, and slow, use-dependent block stimulated by strong depolarizing pulses. Fast block by the peptide ac-KIFMK-NH2, measured on sodium channels whose inactivation was slowed by the α-scorpion toxin from Leiurus quinquestriatus (LqTx), was reversed with a time constant of 0.9 ms upon repolarization. In contrast, control and LqTx-modified sodium channels were slower to recover from use-dependent block. For fast block, linear peptides of three to six amino acid residues containing the IFM motif and two positive charges were more effective than peptides with one positive charge, whereas uncharged IFM peptides were ineffective. Substitution of the IFM residues in the peptide ac-KIFMK-NH2 with smaller, less hydrophobic residues prevented fast block. The positively charged tripeptide IFM-NH2 did not cause appreciable fast block, but the divalent cation IFM-NH(CH2)2NH2 was as effective as the pentapeptide ac-KIFMK-NH2. The constrained peptide cyclic KIFMK containing two positive charges did not cause fast block. These results indicate that the position of the positive charges is unimportant, but flexibility or conformation of the IFM-containing peptide is important to allow fast block. Slow, use-dependent block was observed with IFM-containing peptides of three to six residues having one or two positive charges, but not with dipeptides or phenylalanine-amide. In contrast to its lack of fast block, cyclic KIFMK was an effective use-dependent blocker. Substitutions of amino acid residues in the tripeptide IFM-NH2 showed that large hydrophobic residues are preferred in all three positions for slow, use-dependent block. However, substitution of the large hydrophobic residue diphenylalanine or the constrained residues phenylglycine or tetrahydroisoquinoline for phe decreased potency, suggesting that this phe residue must be able to enter a restricted hydrophobic pocket during the binding of IFM peptides. Together, the results on fast block and slow, use-dependent block indicate that IFM peptides form two distinct complexes of different stability and structural specificity with receptor site(s) on the sodium channel. It is proposed that fast block represents binding of these peptides to the inactivation gate receptor, while slow, use-dependent block represents deeper binding of the IFM peptides in the pore. PMID:9925825

40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized, coupled...

Enhanced Resolution of Chiral Amino Acids with Capillary Electrophoresis for Biosignature Detection in Extraterrestrial Samples.

PubMed

Creamer, Jessica S; Mora, Maria F; Willis, Peter A

2017-01-17

Amino acids are fundamental building blocks of terrestrial life as well as ubiquitous byproducts of abiotic reactions. In order to distinguish between amino acids formed by abiotic versus biotic processes it is possible to use chemical distributions to identify patterns unique to life. This article describes two capillary electrophoresis methods capable of resolving 17 amino acids found in high abundance in both biotic and abiotic samples (seven enantiomer pairs d/l-Ala, -Asp, -Glu, -His, -Leu, -Ser, -Val and the three achiral amino acids Gly, β-Ala, and GABA). To resolve the 13 neutral amino acids one method utilizes a background electrolyte containing γ-cyclodextrin and sodium taurocholate micelles. The acidic amino acid enantiomers were resolved with γ-cyclodextrin alone. These methods allow detection limits down to 5 nM for the neutral amino acids and 500 nM for acidic amino acids and were used to analyze samples collected from Mono Lake with minimal sample preparation.

On the abiotic formation of amino acids. I - HCN as a precursor of amino acids detected in extracts of lunar samples. II - Formation of HCN and amino acids from simulated mixtures of gases released from lunar samples

NASA Technical Reports Server (NTRS)

Yuasa, S.; Flory, D.; Basile, B.; Oro, J.

1984-01-01

Two studies on the abiotic formation of amino acids are presented. The first study demonstrates the role of hydrogen cyanide as a precursor of amino acids detected in extracts of lunar samples. The formation of several amino acids, including glycine, alanine, aspartic acid, and glutamic acid, under conditions similar to those used for the analysis of lunar samples is demonstrated. The second study investigates the formation of hydrogen cyanide as well as amino acids from lunar-sample gas mixtures under electrical discharge conditions. These results extend the possibility of synthesis of amino acids to planetary bodies with primordial atmospheres less reducing than a mixture of methane, ammonia, hydrogen and water.

Information transfer from peptide nucleic acids to RNA by template-directed syntheses

NASA Technical Reports Server (NTRS)

Schmidt, J. G.; Nielsen, P. E.; Orgel, L. E.; Bada, J. L. (Principal Investigator)

1997-01-01

Peptide nucleic acids (PNAs) are uncharged analogs of DNA and RNA in which the ribose-phosphate backbone is substituted by a backbone held together by amide bonds. PNAs are interesting as models of alternative genetic systems because they form potentially informational base paired helical structures. A PNA C10 oligomer has been shown to act as template for efficient formation of oligoguanylates from activated guanosine ribonucleotides. In a previous paper we used heterosequences of DNA as templates in sequence-dependent polymerization of PNA dimers. In this paper we show that information can be transferred from PNA to RNA. We describe the reactions of activated mononucleotides on heterosequences of PNA. Adenylic, cytidylic and guanylic acids were incorporated into the products opposite their complement on PNA, although less efficiently than on DNA templates.

ATP-dependent export of neutral amino acids by vacuolar membrane vesicles of Saccharomyces cerevisiae.

PubMed

Ishimoto, Masaya; Sugimoto, Naoko; Sekito, Takayuki; Kawano-Kawada, Miyuki; Kakinuma, Yoshimi

2012-01-01

Amino acid analysis of Saccharomyces cerevisiae cells indicated that neutral amino acids such as glycine and alanine were probably excluded from the vacuoles, and that vacuolar H(+)-ATPase (V-ATPase) was involved in the vacuolar compartmentalization of these amino acids. We found that vacuolar membrane vesicles export neutral amino acids in an ATP-dependent manner. This is important in identifying vacuolar transporters for neutral amino acids.

Free amino acids and 5'-nucleotides in Finnish forest mushrooms.

PubMed

Manninen, Hanna; Rotola-Pukkila, Minna; Aisala, Heikki; Hopia, Anu; Laaksonen, Timo

2018-05-01

Edible mushrooms are valued because of their umami taste and good nutritional values. Free amino acids, 5'-nucleotides and nucleosides were analyzed from four Nordic forest mushroom species (Lactarius camphoratus, Boletus edulis, Cantharellus cibarius, Craterellus tubaeformis) using high precision liquid chromatography analysis. To our knowledge, these taste components were studied for the first time from Craterellus tubaeformis and Lactarius camphoratus. The focus was on the umami amino acids and 5'-nucleotides. The free amino acid and 5'-nucleotide/nucleoside contents of studied species differed from each other. In all studied samples, umami amino acids were among five major free amino acids. The highest concentration of umami amino acids was on L. camphoratus whereas B. edulis had the highest content of sweet amino acids and C. cibarius had the highest content of bitter amino acids. The content of umami enhancing 5'-nucleotides were low in all studied species. Copyright © 2017 Elsevier Ltd. All rights reserved.

Amino acid catabolism: a pivotal regulator of innate and adaptive immunity

PubMed Central

McGaha, Tracy L.; Huang, Lei; Lemos, Henrique; Metz, Richard; Mautino, Mario; Prendergast, George C.; Mellor, Andrew L.

2014-01-01

Summary Enhanced amino acid catabolism is a common response to inflammation, but the immunologic significance of altered amino acid consumption remains unclear. The finding that tryptophan catabolism helped maintain fetal tolerance during pregnancy provided novel insights into the significance of amino acid metabolism in controlling immunity. Recent advances in identifying molecular pathways that enhance amino acid catabolism and downstream mechanisms that affect immune cells in response to inflammatory cues support the notion that amino acid catabolism regulates innate and adaptive immune cells in pathologic settings. Cells expressing enzymes that degrade amino acids modulate antigen-presenting cell and lymphocyte functions and reveal critical roles for amino acid- and catabolite-sensing pathways in controlling gene expression, functions, and survival of immune cells. Basal amino acid catabolism may contribute to immune homeostasis that prevents autoimmunity, whereas elevated amino acid catalytic activity may reinforce immune suppression to promote tumorigenesis and persistence of some pathogens that cause chronic infections. For these reasons, there is considerable interest in generating novel drugs that inhibit or induce amino acid consumption and target downstream molecular pathways that control immunity. In this review, we summarize recent developments and highlight novel concepts and key outstanding questions in this active research field. PMID:22889220

Correlating Mineralogy and Amino Acid Contents of Milligram-Scale Murchison Carbonaceous Chondrite Samples

NASA Technical Reports Server (NTRS)

Burton, Aaron, S.; Berger, Eve L.; Locke, Darren R.; Elsila, Jamie E.; Glavin, Daniel P.; Dworkin, Jason P.

2015-01-01

Amino acids, the building blocks of proteins, have been found to be indigenous in most of the carbonaceous chondrite groups. The abundances of amino acids, as well as their structural, enantiomeric and isotopic compositions differ significantly among meteorites of different groups and petrologic types. This suggests that there is a link between parent-body conditions, mineralogy and the synthesis and preservation of amino acids (and likely other organic molecules). However, elucidating specific causes for the observed differences in amino acid composition has proven extremely challenging because samples analyzed for amino acids are typically much larger ((is) approximately 100 mg powders) than the scale at which meteorite heterogeneity is observed (sub mm-scale differences, (is) approximately 1-mg or smaller samples). Thus, the effects of differences in mineralogy on amino acid abundances could not be easily discerned. Recent advances in the sensitivity of instrumentation have made possible the analysis of smaller samples for amino acids, enabling a new approach to investigate the link between mineralogical con-text and amino acid compositions/abundances in meteorites. Through coordinated mineral separation, mineral characterization and highly sensitive amino acid analyses, we have performed preliminary investigations into the relationship between meteorite mineralogy and amino acid composition. By linking amino acid data to mineralogy, we have started to identify amino acid-bearing mineral phases in different carbonaceous meteorites. The methodology and results of analyses performed on the Murchison meteorite are presented here.

Peptide Probes Reveal a Hydrophobic Steric Ratchet in the Anthrax Toxin Protective Antigen Translocase.

PubMed

Colby, Jennifer M; Krantz, Bryan A

2015-11-06

Anthrax toxin is a tripartite virulence factor produced by Bacillus anthracis during infection. Under acidic endosomal pH conditions, the toxin's protective antigen (PA) component forms a transmembrane channel in host cells. The PA channel then translocates its two enzyme components, lethal factor and edema factor, into the host cytosol under the proton motive force. Protein translocation under a proton motive force is catalyzed by a series of nonspecific polypeptide binding sites, called clamps. A 10-residue guest/host peptide model system, KKKKKXXSXX, was used to functionally probe polypeptide-clamp interactions within wild-type PA channels. The guest residues were Thr, Ala, Leu, Phe, Tyr, and Trp. In steady-state translocation experiments, the channel blocked most tightly with peptides that had increasing amounts of nonpolar surface area. Cooperative peptide binding was observed in the Trp-containing peptide sequence but not the other tested sequences. Trp substitutions into a flexible, uncharged linker between the lethal factor amino-terminal domain and diphtheria toxin A chain expedited translocation. Therefore, peptide-clamp sites in translocase channels can sense large steric features (like tryptophan) in peptides, and while these steric interactions may make a peptide translocate poorly, in the context of folded domains, they can make the protein translocate more rapidly presumably via a hydrophobic steric ratchet mechanism. Copyright © 2015 The Authors. Published by Elsevier Ltd.. All rights reserved.

Effects of mutations at amino acid 61 in the arm of TF1 on its DNA-binding properties.

PubMed

Sayre, M H; Geiduschek, E P

1990-12-20

Transcription factor 1 (TF1) is the Bacillus subtilis phage SPO1-encoded member of the family of bacterial DNA-binding proteins that includes Escherichia coli HU and integration host factor (IHF). We have initiated a mutational analysis of the TF1 molecule to understand better its unique DNA-binding properties and to investigate its physiological function. We report here the consequences of mutating the putative DNA-binding "arms" of TF1. At position 61 in its primary sequence, TF1 contains a Phe residue in place of the Arg residue found in all other known members of the HU family. Substituting polar, uncharged residues for Phe61 substantially reduced the DNA-binding affinity and site-selectivity of TF1 in vitro, whereas the substitution of Tyr had no effect. Substituting Trp or Arg for Phe61 had little effect on the affinity of TF1 for SPO1 DNA, but altered the electrophoretic mobilities of protein-DNA complexes in non-denaturing gels. The Arg61 substitution increased the affinity of the protein for non-specific sites on thymine-containing DNA, thus reducing the natural preference of TF1 for (5-hydroxymethyluracil)-containing DNA. The Phe61-to-Arg mutation was also correlated with decreased phage yield and aberrant regulation of viral protein synthesis in vivo.

Indole Localization in an Explicit Bilayer Revealed via Molecular Dynamics

NASA Astrophysics Data System (ADS)

Norman, Kristen

2005-11-01

It is well known that the amino-acid tryptophan is particularly stable in the interfacial region of biological membranes, and this preference is a property of the tryptophan side-chain. Analogues of this side-chain, such as indole, strongly localize in the interfacial region, especially near the glycerol moiety of the lipids in the bilayer. Using molecular dynamics calculations, we determine the potential of mean force (PMF) for indoles in the bilayer. We compare the calculated PMF for indole with that of benzene to show that exclusion from the center of the lipid bilayer does not occur in all aromatics, but is strong in indoles. We find three minima in the PMF. Indole is most stabilized near the glycerol moiety. A weaker binding location is found near the choline groups of the lipid molecules. An even weaker binding side is found near the center of the lipid hydrocarbon core. Comparisions between uncharged, weakly charged, and highly charged indoles demonstrate that the exclusion is caused by the charge distribution on the indole rather than the ``lipo-phobic'' effect. High temperature simulations are used to determine the relative contribution of enthalpy and entropy to indole localization. The orientation of indole is found to be largely charge independent and is a strong function of depth within the bilayer. We find good agreement between simulated SCD order parameters for indole and experimentally determined order parameters.

Capillary Electrophoresis of Mono- and Oligosaccharides.

PubMed

Toppazzini, Mila; Coslovi, Anna; Rossi, Marco; Flamigni, Anna; Baiutti, Edi; Campa, Cristiana

2016-01-01

This chapter reports an overview of the recent advances in the analysis of mono- and oligosaccharides by capillary electrophoresis (CE); furthermore, relevant reviews and research articles recently published in the field are tabulated. Additionally, pretreatments and procedures applied to uncharged and acidic carbohydrates (i.e., monosaccharides and lower oligosaccharides carrying carboxylate, sulfate, or phosphate groups) are described.Representative examples of such procedures are reported in detail, upon describing robust methodologies for the study of (1) neutral oligosaccharides derivatized by reductive amination and by formation of glycosylamines; (2) sialic acid derivatized with 2-aminoacridone, released from human serum immunoglobulin G; (3) anomeric couples of neutral glycosides separated using borate-based buffers; (4) unsaturated, underivatized oligosaccharides from lyase-treated alginate.

Anesthetics mechanism on a DMPC lipid membrane model: Insights from molecular dynamics simulations.

PubMed

Saeedi, Marzieh; Lyubartsev, Alexander P; Jalili, Seifollah

2017-07-01

To provide insight into the molecular mechanisms of local anesthetic action, we have carried out an extensive investigation of two amide type local anesthetics, lidocaine and articaine in both charged and uncharged forms, interacting with DMPC lipid membrane. We have applied both standard molecular dynamics simulations and metadynamics simulations to provide a detailed description of the free energy landscape of anesthetics embedded in the lipid bilayer. The global minimum of the free energy surface (equilibrium position of anesthetics in the lipid membrane) occurred around 1nm of the bilayer center. The uncharged anesthetics show more affinity to bind to this region compared to the charged drugs. The binding free energy of uncharged lidocaine in the membrane (-30.3kJ/mol) is higher than uncharged articaine (-24.0kJ/mol), which is in good agreement with higher lipid solubility of lidocaine relative to the articaine. The octanol/water partition coefficient of uncharged drugs was also investigated using expanded ensemble simulations. In addition, complementary standard MD simulations were carried out to study the partitioning behavior of multiple anesthetics inside the lipid bilayer. The results obtained here are in line with previously reported simulations and suggest that the different forms of anesthetics induce different structural modifications in the lipid bilayer, which can provide new insights into their complex membrane translocation phenomena. Copyright © 2017 Elsevier B.V. All rights reserved.

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.

2009-01-01

Amino acid analysis of a meteorite fragment of asteroid 2008 TC(sub 3) called Almahata Sitta was carried out using reverse-phase high-perfo rmance liquid chromatography coupled with UV fluorescence detection a nd time-of-flight mass spectrometry (HPLC-FD/ToF-MS) as part of a sam ple analysis consortium. HPLC analyses of hot-water extracts from the meteorite revealed a complex distribution of two- to six-carbon aliph atic amino acids and one- to three carbon amines with abundances rang ing from 0.5 to 149 parts-per-billion (ppb). The enantiomeric ratios of the amino acids alanine, Beta-amino-n-butyric acid (Beta-ABA), 2-amino-2- methylbutanoic acid (isovaline), and 2-aminopentanoic acid (no rvaline) in the meteorite were racemic (D/L approximately 1), indicat ing that these amino acids are indigenous to the meteorite and not te rrestrial 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- methybutanoic acid, 4-a mino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. Th e total abundances of isovaline and AlB in Almahata Sitta are approximately 1000 times lower than the abundances of these amino acids found in the CM carbonaceous meteorite Murchison. The extremely love abund ances and unusual distribution of five carbon amino acids in Almahata Sitta compared to Cl, CM, and CR carbonaceous meteorites and may be due to extensive thermal alteration of amino acids on the parent aster oid by partial melting during formation or impact shock heating.

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.

Mated Drosophila melanogaster females consume more amino acids during the dark phase

PubMed Central

Uchizono, Shun; Tabuki, Yumi; Kawaguchi, Natsumi; Tanimura, Teiichi; Itoh, Taichi Q.

2017-01-01

To maintain homeostasis, animals must ingest appropriate quantities, determined by their internal nutritional state, of suitable nutrients. In the fruit fly Drosophila melanogaster, an amino acid deficit induces a specific appetite for amino acids and thus results in their increased consumption. Although multiple processes of physiology, metabolism, and behavior are under circadian control in many organisms, it is unclear whether the circadian clock also modulates such motivated behavior driven by an internal need. Differences in levels of amino acid consumption by flies between the light and dark phases of the day:night cycle were examined using a capillary feeder assay following amino acid deprivation. Female flies exhibited increased consumption of amino acids during the dark phase compared with the light phase. Investigation of mutants lacking a functional period gene (per0), a well-characterized clock gene in Drosophila, found no difference between the light and dark phases in amino acid consumption by per0 flies. Furthermore, increased consumption of amino acids during the dark phase was observed in mated but not in virgin females, which strongly suggested that mating is involved in the rhythmic modulation of amino acid intake. Egg production, which is induced by mating, did not affect the rhythmic change in amino acid consumption, although egg-laying behavior showed a per0-dependent change in rhythm. Elevated consumption of amino acids during the dark phase was partly induced by the action of a seminal protein, sex peptide (SP), on the sex peptide receptor (SPR) in females. Moreover, we showed that the increased consumption of amino acids during the dark phase is induced in mated females independently of their internal level of amino acids. These results suggest that a post-mating SP/SPR signal elevates amino acid consumption during the dark phase via the circadian clock. PMID:28241073

Mated Drosophila melanogaster females consume more amino acids during the dark phase.

PubMed

Uchizono, Shun; Tabuki, Yumi; Kawaguchi, Natsumi; Tanimura, Teiichi; Itoh, Taichi Q

2017-01-01

To maintain homeostasis, animals must ingest appropriate quantities, determined by their internal nutritional state, of suitable nutrients. In the fruit fly Drosophila melanogaster, an amino acid deficit induces a specific appetite for amino acids and thus results in their increased consumption. Although multiple processes of physiology, metabolism, and behavior are under circadian control in many organisms, it is unclear whether the circadian clock also modulates such motivated behavior driven by an internal need. Differences in levels of amino acid consumption by flies between the light and dark phases of the day:night cycle were examined using a capillary feeder assay following amino acid deprivation. Female flies exhibited increased consumption of amino acids during the dark phase compared with the light phase. Investigation of mutants lacking a functional period gene (per0), a well-characterized clock gene in Drosophila, found no difference between the light and dark phases in amino acid consumption by per0 flies. Furthermore, increased consumption of amino acids during the dark phase was observed in mated but not in virgin females, which strongly suggested that mating is involved in the rhythmic modulation of amino acid intake. Egg production, which is induced by mating, did not affect the rhythmic change in amino acid consumption, although egg-laying behavior showed a per0-dependent change in rhythm. Elevated consumption of amino acids during the dark phase was partly induced by the action of a seminal protein, sex peptide (SP), on the sex peptide receptor (SPR) in females. Moreover, we showed that the increased consumption of amino acids during the dark phase is induced in mated females independently of their internal level of amino acids. These results suggest that a post-mating SP/SPR signal elevates amino acid consumption during the dark phase via the circadian clock.

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.

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

PubMed

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

2018-01-01

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

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

NASA Astrophysics Data System (ADS)

Fischlschweiger, Michael; Enders, Sabine; Zeiner, Tim

2014-09-01

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

Amino acids and autophagy: cross-talk and co-operation to control cellular homeostasis.

PubMed

Carroll, Bernadette; Korolchuk, Viktor I; Sarkar, Sovan

2015-10-01

Maintenance of amino acid homeostasis is important for healthy cellular function, metabolism and growth. Intracellular amino acid concentrations are dynamic; the high demand for protein synthesis must be met with constant dietary intake, followed by cellular influx, utilization and recycling of nutrients. Autophagy is a catabolic process via which superfluous or damaged proteins and organelles are delivered to the lysosome and degraded to release free amino acids into the cytoplasm. Furthermore, autophagy is specifically activated in response to amino acid starvation via two key signaling cascades: the mammalian target of rapamycin (mTOR) complex 1 (mTORC1) and the general control nonderepressible 2 (GCN2) pathways. These pathways are key regulators of the integration between anabolic (amino acid depleting) and catabolic (such as autophagy which is amino acid replenishing) processes to ensure intracellular amino acid homeostasis. Here, we discuss the key roles that amino acids, along with energy (ATP, glucose) and oxygen, are playing in cellular growth and proliferation. We further explore how sophisticated methods are employed by cells to sense intracellular amino acid concentrations, how amino acids can act as a switch to dictate the temporal and spatial activation of anabolic and catabolic processes and how autophagy contributes to the replenishment of free amino acids, all to ensure cell survival. Relevance of these molecular processes to cellular and organismal physiology and pathology is also discussed.

Label-free amino acid detection based on nanocomposites of graphene oxide hybridized with gold nanoparticles.

PubMed

Zhang, Qian; Zhang, Diming; Lu, Yanli; Xu, Gang; Yao, Yao; Li, Shuang; Liu, Qingjun

2016-03-15

Nanocomposites of graphene oxide and gold nanoparticles (GO/GNPs) were synthesized for label-free detections of amino acids. Interactions between the composites and amino acids were investigated by both naked-eye observation and optical absorption spectroscopy. The GO/GNPs composites displayed apparent color changes and absorption spectra changes in presences of amino acids including glutamate, aspartate, and cysteine. The interaction mechanisms of the composites and amino acids were discussed and explored with sulfhydryl groups and non-α-carboxylic groups on the amino acids. Sensing properties of the composites were tested, while pure gold particles were used as the control. The results suggested that the GO/GNPs composites had better linearity and stability in dose-dependent responses to the amino acids than those of the particles, especially in detections for acidic amino acids. Therefore, the nanocomposites platform can provide a convenient and efficient approach for label-free optical detections of important molecules such as amino acids. Copyright © 2015 Elsevier B.V. All rights reserved.

Mechanisms of volatile production from non-sulfur amino acids by irradiation

NASA Astrophysics Data System (ADS)

Ahn, Dong Uk; Lee, Eun Joo; Feng, Xi; Zhang, Wangang; Lee, Ji Hwan; Jo, Cheorun; Nam, Kichang

2016-02-01

Non-sulfur amino acid monomers were used to study the mechanisms of volatile production in meat by irradiation. Irradiation not only produced many volatiles but also increased the amounts of volatiles from non-sulfur amino acid monomers. The major reaction mechanisms involved in volatile production from each group of the amino acids by irradiation differ significantly. However, we speculate that the radiolysis of amino acid side chains were the major mechanism. In addition, Strecker degradation, especially the production of aldehydes from aliphatic group amino acids, and deamination, isomerization, decarboxylation, cyclic reaction and dehydrogenation of the initial radiolytic products were also contributed to the production of volatile compounds. Each amino acid monomers produced different odor characteristics, but the intensities of odor from all non-sulfur amino acid groups were very weak. This indicated that the contribution of volatiles produced from non-sulfur amino acids was minor. If the volatile compounds from non-sulfur amino acids, especially aldehydes, interact with other volatiles compounds such as sulfur compounds, however, they can contribute to the off-odor of irradiated meat significantly.

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.

Influence of biopolymers on the solubility of branched-chain amino acids and stability of their solutions.

PubMed

Hong, Chi Rac; Lee, Gyu Whan; Paik, Hyun-Dong; Chang, Pahn-Shick; Choi, Seung Jun

2018-01-15

This study confirmed the possibility of biopolymer-type stabilizers to increase the saturation concentration of branched-chain amino acids by preventing their crystallization/precipitation. Although microfluidization increased the initial solubility, it failed to increase the saturation concentration of the branched-chain amino acids. The saturation concentration of the branched-chain amino acids increased from 3.81% to 4.42% and 4.85% after the incorporation of food hydrocolloids and proteins, respectively. However, the branched-chain amino acids:stabilizer ratio did not affect the solubility. In the case of food hydrocolloid-based solutions, crystal formation and growth of branched-chain amino acids occurred during storage, resulting in the precipitation of branched-chain amino acid crystals. However, food proteins effectively increased the stability of the solubilized branched-chain amino acids. The improved solubility and stability of the solubilized branched-chain amino acids could be attributed to interactions between the functional groups (carboxyl, amine, sulfate, aliphatic, aromatic, etc.) of the stabilizer and the branched-chain amino acid molecules. Copyright © 2017 Elsevier Ltd. All rights reserved.

Effects of the pH and Concentration on the Stability of Standard Solutions of Proteinogenic Amino Acid Mixtures.

PubMed

Kato, Megumi; Yamazaki, Taichi; Kato, Hisashi; Yamanaka, Noriko; Takatsu, Akiko; Ihara, Toshihide

2017-01-01

To prepare metrologically traceable amino acid mixed standard solutions, it is necessary to determine the stability of each amino acid present in the mixed solutions. In the present study, we prepared amino acid mixed solutions using certified reference standards of 17 proteinogenic amino acids, and examined the stability of each of these amino acids in 0.1 N HCl. We found that the concentration of glutamic acid decreased significantly during storage. LC/MS analysis indicated that the instability of glutamic acid was due to the partial degradation of glutamic acid to pyroglutamic acid in 0.1 N HCl. Using accelerated degradation tests, we investigated several solvent compositions to improve the stability of glutamic acid in amino acid mixed solution, and determined that the change of the pH by diluting the mixed solution improved the stability of glutamic acid.

Solute transport on the sub 100 ms scale across the lipid bilayer membrane of individual proteoliposomes.

PubMed

Ohlsson, Gabriel; Tabaei, Seyed R; Beech, Jason; Kvassman, Jan; Johanson, Urban; Kjellbom, Per; Tegenfeldt, Jonas O; Höök, Fredrik

2012-11-21

Screening assays designed to probe ligand and drug-candidate regulation of membrane proteins responsible for ion-translocation across the cell membrane are wide spread, while efficient means to screen membrane-protein facilitated transport of uncharged solutes are sparse. We report on a microfluidic-based system to monitor transport of uncharged solutes across the membrane of multiple (>100) individually resolved surface-immobilized liposomes. This was accomplished by rapidly switching (<10 ms) the solution above dye-containing liposomes immobilized on the floor of a microfluidic channel. With liposomes encapsulating the pH-sensitive dye carboxyfluorescein (CF), internal changes in pH induced by transport of a weak acid (acetic acid) could be measured at time scales down to 25 ms. The applicability of the set up to study biological transport reactions was demonstrated by examining the osmotic water permeability of human aquaporin (AQP5) reconstituted in proteoliposomes. In this case, the rate of osmotic-induced volume changes of individual proteoliposomes was time resolved by imaging the self quenching of encapsulated calcein in response to an osmotic gradient. Single-liposome analysis of both pure and AQP5-containing liposomes revealed a relatively large heterogeneity in osmotic permeability. Still, in the case of AQP5-containing liposomes, the single liposome data suggest that the membrane-protein incorporation efficiency depends on liposome size, with higher incorporation efficiency for larger liposomes. The benefit of low sample consumption and automated liquid handling is discussed in terms of pharmaceutical screening applications.

Monoanionic 99mTc-tricarbonyl-aminopolycarboxylate complexes with uncharged pendant groups: Radiosynthesis and evaluation as potential renal tubular tracers.

PubMed

Lipowska, Malgorzata; Klenc, Jeffrey; Jarkas, Nashwa; Marzilli, Luigi G; Taylor, Andrew T

2017-04-01

99m Tc(CO) 3 -nitrilotriacetic acid, 99m Tc(CO) 3 (NTA), is a new renal tubular agent with pharmacokinetic properties comparable to those of 131 I-OIH but the clearance of 99m Tc(CO) 3 (NTA) and 131 I-OIH is still less than the clearance of PAH, the gold standard for the measurement of effective renal plasma flow. At physiological pH, dianionic 99m Tc(CO) 3 (NTA) has a mononegative inner metal-coordination sphere and a mononegative uncoordinated carboxyl group. To evaluate alternate synthetic approaches, we assessed the importance of an uncoordinated carboxyl group, long considered essential for tubular transport, by evaluating the pharmacokinetics of three analogs with the 99m Tc(CO) 3 (NTA) metal-coordination sphere but with uncharged pendant groups. 99m Tc(CO) 3 complexes with N-(2-acetamido)iminodiacetic acid (ADA), N-(2-hydroxyethyl)iminodiacetic acid (HDA) and N-(fluoroethyl)iminodiacetic acid (FEDA) were prepared using a tricarbonyl kit and isolated by HPLC. The pharmacokinetics were evaluated in Sprague-Dawley rats, with 131 I-OIH as an internal control; urine was analyzed for metabolites. Plasma protein binding and erythrocyte uptake were determined from the 10min blood samples. Re(CO) 3 (FEDA), the analog of 99m Tc(CO) 3 (FEDA), was prepared and characterized. 99m Tc(CO) 3 (ADA), 99m Tc(CO) 3 (HDA) and 99m Tc(CO) 3 (FEDA) were efficiently prepared as a single species with high radiochemical purities (>99%). These new monoanionic 99m Tc(CO) 3 tracers with uncharged dangling groups all showed rapid blood clearance and high specificity for renal excretion. Activity in the urine, as a percent of 131 I-OIH at 10 and 60min, was 96% and 99% for ADA, 96% and 100% for HDA, and 100% and 99% for FEDA, respectively. Each new tracer was excreted unchanged in the urine. The Re(CO) 3 (FEDA) structure adds compelling evidence that such 99m Tc(CO) 3 (NTA) analogs have metal-coordination spheres identical to that of 99m Tc(CO) 3 (NTA). New tracers lacking the negatively charged pendant carboxyl group previously thought to be essential for rapid renal extraction, 99m Tc(CO) 3 (ADA), 99m Tc(CO) 3 (HDA) and 99m Tc(CO) 3 (FEDA), exhibit pharmacokinetics in rats comparable to those of 99m Tc(CO) 3 (NTA) and 131 I-OIH. Furthermore, these encouraging results in rats warrant evaluation of this new tracer type in humans. Copyright © 2016 Elsevier Inc. All rights reserved.

Serum Amino Acid Profiling in Citrin-Deficient Children Exhibiting Normal Liver Function During the Apparently Healthy Period.

PubMed

Miyazaki, Teruo; Nagasaka, Hironori; Komatsu, Haruki; Inui, Ayano; Morioka, Ichiro; Tsukahara, Hirokazu; Kaji, Shunsaku; Hirayama, Satoshi; Miida, Takashi; Kondou, Hiroki; Ihara, Kenji; Yagi, Mariko; Kizaki, Zenro; Bessho, Kazuhiko; Kodama, Takahiro; Iijima, Kazumoto; Yorifuji, Tohru; Matsuzaki, Yasushi; Honda, Akira

2018-04-14

Citrin (mitochondrial aspartate-glutamate transporter) deficiency causes the failures in both carbohydrate-energy metabolism and the urea cycle, and the alterations in the serum levels of several amino acids in the stages of newborn (NICCD) and adult (CTLN2). However, the clinical manifestations are resolved between the NICCD and CTLN2, but the reasons are still unclear. This study evaluated the serum amino acid profile in citrin-deficient children during the healthy stage. Using HPLC-MS/MS analysis, serum amino acids were evaluated among 20 citrin-deficient children aged 5-13 years exhibiting normal liver function and 35 age-matched healthy controls. The alterations in serum amino acids characterized in the NICCD and CTLN2 stages were not observed in the citrin-deficient children. Amino acids involved in the urea cycle, including arginine, ornithine, citrulline, and aspartate, were comparable in the citrin-deficient children to the respective control levels, but serum urea was twofold higher, suggestive of a functional urea cycle. The blood sugar level was normal, but glucogenic amino acids and glutamine were significantly decreased in the citrin-deficient children compared to those in the controls. In addition, significant increases of ketogenic amino acids, branched-chain amino acids (BCAAs), a valine intermediate 3-hydroxyisobutyrate, and β-alanine were also found in the citrin-deficient children. The profile of serum amino acids in the citrin-deficient children during the healthy stage showed different characteristics from the NICCD and CTLN2 stages, suggesting that the failures in both urea cycle function and energy metabolism might be compensated by amino acid metabolism. In the citrin-deficient children during the healthy stage, the characteristics of serum amino acids, including decrease of glucogenic amino acids, and increase of ketogenic amino acids, BCAAs, valine intermediate, and β-alanine, were found by comparison to the age-matched healthy control children, and it suggested that the characteristic alteration of serum amino acids may be resulted from compensation for energy metabolism and ammonia detoxification.

Molecular basis of essential amino acid transport from studies of insect nutrient amino acid transporters of the SLC6 family (NAT-SLC6)

PubMed Central

Boudko, Dmitri Y.

2012-01-01

Two protein families that represent major components of essential amino acid transport in insects have been identified. They are annotated as the SLC6 and SLC7 families of transporters according to phylogenetic proximity to characterized amino acid transporters (HUGO nomenclature). Members of these families have been identified as important apical and basolateral parts of transepithelial essential amino acid absorption in the metazoan alimentary canal. Synergistically, they play critical physiological roles as essential substrate providers to diverse metabolic processes, including generic protein synthesis. This review briefly clarifies the requirements for amino acid transport and a variety of amino acid transport mechanisms, including the aforementioned families. Further it focuses on the large group of Nutrient Amino acid Transporters (NATs), which comprise a recently identified subfamily of the Neurotransmitter Sodium Symporter family (NSS or SLC6). The first insect NAT, cloned from the caterpillar gut, has a broad substrate spectrum similar to mammalian B0 transporters. Several new NAT-SLC6 members have been characterized in an effort to explore mechanisms for the essential amino acid absorption in model dipteran insects. The identification and functional characterization of new B0-like and narrow specificity transporters of essential amino acids in fruit fly and mosquitoes leads to a fundamentally important insight: that NATs evolved and act together as the integrated active core of a transport network that mediates active alimentary absorption and systemic distribution of essential amino acids. This role of NATs is projected from the most primitive prokaryotes to the most complex metazoan organisms, and represents an interesting platform for unraveling the molecular evolution of amino acid transport and modeling amino acid transport disorders. The comparative study of NATs elucidates important adaptive differences between essential amino acid transportomes of invertebrate and vertebrate organisms, outlining a new possibility for selective targeting of essential amino acid absorption mechanisms to control medically and economically important arthropods and other invertebrate organisms. PMID:22230793

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 of the total quantity of amino acids after acid hydrolysis, due to the formation/release of amino acids during the whole water extraction / liquid-phase acid hydrolysis, could have hidden a loss of amino acids. Thus, in extraterrestrial material studies involving liquid-phase acid hydrolysis, the quantities of total amino acids may have been underestimated.

Determination of amino acids in grape-derived products: a review.

PubMed

Callejón, R M; Troncoso, A M; Morales, M L

2010-06-15

The amino acids present in foods and beverages affect the quality of these products and they play an important role in enology. Amino acids are consumed by yeasts as a source of nitrogen during alcoholic fermentation and are precursors of aroma compounds. In this review various chromatographic methodologies for the determination of amino acids are described, and specific applications for the analysis of amino acid content are discussed. Amino acids usually need to be derivatized to make them more detectable. Several derivatizing reagents have been employed for the determination of amino acids in enological applications, and each has its advantages and disadvantages.

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

The tip and hidden part of the iceberg: Proteinogenic and non-proteinogenic aliphatic amino acids.

PubMed

Fichtner, Maximilian; Voigt, Kerstin; Schuster, Stefan

2017-01-01

Amino acids are the essential building blocks of proteins and, therefore, living organisms. While the focus often lies on the canonical or proteinogenic amino acids, there is also a large number of non-canonical amino acids to explore. Some of them are part of toxins or antibiotics in fungi, bacteria or animals (e.g. sponges). Some others operate at the translational level like an "undercover agent". Here we give an overview of natural aliphatic amino acids, up to a side chain length of five carbons, without rings and with an unmodified backbone, and have a closer look on each of them. Some of them are dehydro amino acids with double or even triple bonds. Moreover, we outline mathematical methods for enumerating the complete list of all potential aliphatic amino acids of a given chain length. This should be of interest for synthetic biology. Most non-proteinogenic amino acids are found within fungi, with particularly many produced by Amanita species as defence chemicals. Several are incorporated into peptide antibiotics. Some of the amino acids occur due to broad substrate specificity of the branched-chain amino acid synthesis pathways. A large variety of amino acids were also found in the Murchison meteorite. Non-proteinogenic amino acids are of interest for numerous medical applications: discovery of new antibiotics, support in designing synthetic antibiotics, improvement of protein and peptide pharmaceuticals by avoiding incorporation of non-canonical amino acids, study of toxic cyanobacteria and other applications. Copyright © 2016 Elsevier B.V. All rights reserved.

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.

Predicting Thermodynamic Behaviors of Non-Protein Amino Acids as a Function of Temperature and pH

NASA Astrophysics Data System (ADS)

Kitadai, Norio

2016-03-01

Why does life use α-amino acids exclusively as building blocks of proteins? To address that fundamental question from an energetic perspective, this study estimated the standard molal thermodynamic data for three non-α-amino acids (β-alanine, γ-aminobutyric acid, and ɛ-aminocaproic acid) and α-amino- n-butyric acid in their zwitterionic, negative, and positive ionization states based on the corresponding experimental measurements reported in the literature. Temperature dependences of their heat capacities were described based on the revised Helgeson-Kirkham-Flowers (HKF) equations of state. The obtained dataset was then used to calculate the standard molal Gibbs energies ( ΔG o) of the non-α-amino acids as a function of temperature and pH. Comparison of their ΔG o values with those of α-amino acids having the same molecular formula showed that the non-α-amino acids have similar ΔG o values to the corresponding α-amino acids in physiologically relevant conditions (neutral pH, <100 °C). In acidic and alkaline pH, the non-α-amino acids are thermodynamically more stable than the corresponding α-ones over a broad temperature range. These results suggest that the energetic cost of synthesis is not an important selection pressure to incorporate α-amino acids into biological systems.

Predicting Thermodynamic Behaviors of Non-Protein Amino Acids as a Function of Temperature and pH.

PubMed

Kitadai, Norio

2016-03-01

Why does life use α-amino acids exclusively as building blocks of proteins? To address that fundamental question from an energetic perspective, this study estimated the standard molal thermodynamic data for three non-α-amino acids (β-alanine, γ-aminobutyric acid, and ε-aminocaproic acid) and α-amino-n-butyric acid in their zwitterionic, negative, and positive ionization states based on the corresponding experimental measurements reported in the literature. Temperature dependences of their heat capacities were described based on the revised Helgeson-Kirkham-Flowers (HKF) equations of state. The obtained dataset was then used to calculate the standard molal Gibbs energies (∆G (o)) of the non-α-amino acids as a function of temperature and pH. Comparison of their ∆G (o) values with those of α-amino acids having the same molecular formula showed that the non-α-amino acids have similar ∆G (o) values to the corresponding α-amino acids in physiologically relevant conditions (neutral pH, <100 °C). In acidic and alkaline pH, the non-α-amino acids are thermodynamically more stable than the corresponding α-ones over a broad temperature range. These results suggest that the energetic cost of synthesis is not an important selection pressure to incorporate α-amino acids into biological systems.

Amino acid composition of two masticatory nuts (Cola acuminata and Garcinia kola) and a snack nut (Anacardium occidentale).

PubMed

Adeyeye, E I; Asaolu, S S; Aluko, A O

2007-06-01

The amino acid compositions of Cola acuminata, Garcinia kola and Anacardium occidentale were evaluated by ion-exchange chromatography. Glutamic acid was the most concentrated acid in the samples. In all the amino acids determined, A. occidentale had the most concentrated acid on a pairwise basis. The total amino acids were 356.24 mg/g protein, 112.90 mg/g protein and 659.17 mg/g protein for C. acuminata, G. kola and A. occidentale, respectively. The percentage total essential amino acids were 38.39% (C. acuminata), 47.05% (G. kola) and 51.04% (A. occidentale). Also the percentage total acidic amino acids were 38.16% (C. acuminata), 30.61% (G. kola) and 30.35% (A. occidentale). The calculated isoelectric points were 2.0 (C. acuminata), 0.7 (G. kola) and 3.9 (A. occidentale), showing they can all be precipitated at acidic pH. While threonine was the limiting amino acid in A. occidentale, it was valine in both C. acuminata and G. kola. The percentage cystine (Cys) levels in the total sulphur amino acid were 44.27% (C. acuminata), 37.75% (G. kola) and 50.51% (A. occidentale). The aim of this work was to compare the amino acid profile of the samples. It is recommended that C. acuminata and G. kola consumption be avoided by ulcer patients because of their high levels of acidic amino acids. A. occidentale amino acid scores ranged from 42% to 127%, suggesting that it could be used to enhance the protein quality of cereals through food complementation.

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

PubMed

Korus, Anna

2012-02-01

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

Analysis of amino acids by HPLC/electrospray negative ion tandem mass spectrometry using 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) derivatization.

PubMed

Ziegler, Jörg; Abel, Steffen

2014-12-01

A new method for the determination of amino acids is presented. It combines established methods for the derivatization of primary and secondary amino groups with 9-fluorenylmethoxycarbonyl chloride (Fmoc-Cl) with the subsequent amino acid specific detection of the derivatives by LC-ESI-MS/MS using multiple reaction monitoring (MRM). The derivatization proceeds within 5 min, and the resulting amino acid derivatives can be rapidly purified from matrix by solid-phase extraction (SPE) on HR-X resin and separated by reversed-phase HPLC. The Fmoc derivatives yield several amino acid specific fragment ions which opened the possibility to select amino acid specific MRM transitions. The method was applied to all 20 proteinogenic amino acids, and the quantification was performed using L-norvaline as standard. A limit of detection as low as 1 fmol/µl with a linear range of up to 125 pmol/µl could be obtained. Intraday and interday precisions were lower than 10 % relative standard deviations for most of the amino acids. Quantification using L-norvaline as internal standard gave very similar results compared to the quantification using deuterated amino acid as internal standards. Using this protocol, it was possible to record the amino acid profiles of only a single root from Arabidopsis thaliana seedlings and to compare it with the amino acid profiles of 20 dissected root meristems (200 μm).

Differential distribution of amino acids in plants.

PubMed

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

2017-05-01

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

Enhanced detection of amino acids in hydrophilic interaction chromatography electrospray tandem mass spectrometry with carboxylic acids as mobile phase additives.

PubMed

Yin, Dengyang; Hu, Xunxiu; Liu, Dantong; Du, Wencheng; Wang, Haibo; Guo, Mengzhe; Tang, Daoquan

2017-06-01

Liquid chromatography coupled with mass spectrometry technique has been widely used in the analysis of biological targets such as amino acids, peptides, and proteins. In this work, eight common single carboxylic acids or diacids, which contain different pKa have been investigated as the additives to the analysis of amino acids. As the results, carboxylic acid additive can improve the signal intensity of acidity amino acids such as Asp and Glu and the chromatographic separation of basic amino acids such as Arg, His, and Lys. In particular, the diacids have better performance than single acids. The proposed mechanism is that the diacid has hydrogen bond interaction with amino acids to reduce their polarity/amphiprotic characteristics. Besides, oxalic acid has been found having better enhancement than phthalic acid by overall consideration. Therefore, we successfully quantified the 15 amino acids in Sepia bulk pharmaceutical chemical by using oxalic acid as the additive.

Unprecedented concentrations of indigenous amino acids in primitive CR meteorites

NASA Astrophysics Data System (ADS)

Ehrenfreund, Pascale; Martins, Zita; Alexander, Conel; Orzechowska, Grazyna; Fogel, Marylin

CR meteorites are among the most primitive meteorites. We have performed pioneering work determining the compositional characteristics of amino acids in this type of carbonaceous chondrites. We report the first measurements of amino acids in Antarctic CR meteorites, two of which show the highest amino acid concentrations ever found in a chondrite. We have analyzed the amino acid content of the Antarctic CRs EET92042, GRA95229 and GRO95577 using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatography-mass spectrometry (GC-MS). Additionally, compound-specific carbon isotopic measurements for most of the individual amino acids from the EET92042 and GRA95229 meteorites were achieved by gas chromatography-combustion-isotope ratio mass spectrometry (GC-C-IRMS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations of 180 and 249 parts-per-million (ppm), respectively. GRO95577, however, is depleted in amino acids (<1 ppm). The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the α-amino acids glycine, isovaline, α-aminoisobutyric acid (α-AIB), and alanine, with δ 13 C values ranging from +31.6% to +50.5%. The highly enriched carbon isotope results together with racemic enantiomeric ratios determined for most amino acids indicate that primitive organic matter was preserved in these meteorites. In addition, the relative abundances of α-AIB and β-alanine amongst Antarctic CR meteorites appear to correspond to the degree of aqueous alteration on their respective parent body. Investigating the abundances and isotopic composition of amino acids in primitive chondrites helps to understand the role of meteorites as a source of extraterrestrial prebiotic organic compounds to the early Earth.

Effect of age on the concentrations of amino acids in the plasma of healthy foals.

PubMed

Zicker, S C; Spensley, M S; Rogers, Q R; Willits, N H

1991-07-01

The concentrations of 23 amino acids in the plasma of 13 healthy foals were determined before suckling, when foals were 1 to 2 days old, 5 to 7 days old, 12 to 14 days old, and 26 to 28 days old. The ratio of the branched chain amino acids to the aromatic amino acids was also calculated at the 5 time points. Analysis of the concentrations at the 5 ages revealed a significant temporal relationship for each amino acid ranging from a polynomial order of 1 to 4 inclusively. There were significant differences between several concentrations of amino acids in plasma at specific sample times; however, no consistent patterns were revealed. The concentrations of amino acids in healthy foals were markedly different from previously determined values in adult horses. The significant differences in the concentrations of amino acids in plasma of healthy foals at the 5 ages may represent developmental aspects of amino acid metabolism or nutrition.

Inhibitory activity and mechanism of inhibition of the N-[[(4-benzoylamino)phenyl]sulfonyl]amino acid aldose reductase inhibitors.

PubMed

DeRuiter, J; Mayfield, C A

1990-11-15

A series of substituted N-[[(4-benzoylamino)phenyl]sulfonyl]amino acids (BAPS-amino acids) were synthesized by established methods, and the stereochemistry of the products was confirmed by HPLC analysis after chiral derivatization. When tested against aldose reductase (alditol:NADP+ oxidoreductase; EC 1.1.1.21; ALR2) isolated from rat lens, all of the BAPS-amino acids were determined to be significantly more inhibitory than the corresponding N-(phenylsulfonyl)amino acids. Structure-inhibition and enzyme kinetic analyses suggest that the BAPS-amino acids inhibit ALR2 by a mechanism similar to the N-(phenylsulfonyl)amino acids. However, multiple inhibition analyses indicate that the increased inhibitory activity of the BAPS-amino acids is a result of interaction with multiple sites present on ALR2. Enzyme specificity studies with several of the BAPS-amino acids demonstrated that these compounds do not produce significant inhibition of other nucleotide-requiring enzymes including aldehyde reductase (alcohol: NADP+ oxidoreductase; EC 1.1.1.2; ALR1).

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.

Interaction of Atmospheric-Pressure Air Microplasmas with Amino Acids as Fundamental Processes in Aqueous Solution

PubMed Central

Zhou, Renwu; Zhou, Rusen; Zhuang, Jinxing; Zong, Zichao; Zhang, Xianhui; Liu, Dongping; Bazaka, Kateryna; Ostrikov, Kostya

2016-01-01

Plasma medicine is a relatively new field that investigates potential applications of cold atmospheric-pressure plasmas in bioengineering, such as for bacterial inactivation and degradation of organic molecules in water. In order to enunciate mechanisms of bacterial inactivation at molecular or atomic levels, we investigated the interaction of atmospheric-pressure air microplasmas with amino acids in aqueous solution by using high-resolution mass spectrometry (HRMS). Results show that the oxidation effect of plasma-induced species on the side chains of the amino acids can be categorized into four types, namely hydroxylation, nitration, dehydrogenation and dimerization. In addition, relative activities of amino acids resulting from plasma treatment come in descending order as follows: sulfur-containing carbon-chain amino acids > aromatic amino acids > five-membered ring amino acids > basic carbon-chain amino acids. Since amino acids are building blocks of proteins vital to the growth and reproduction of bacteria, these results provide an insight into the mechanism of bacterial inactivation by plasma. PMID:27183129

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

PubMed

Kıvrak, İbrahim; Kıvrak, Şeyda; Harmandar, Mansur

2014-09-01

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

Effect of the quality of dietary amino acids composition on the urea synthesis in rats.

PubMed

Tujioka, Kazuyo; Ohsumi, Miho; Hayase, Kazutoshi; Yokogoshi, Hidehiko

2011-01-01

We have shown that urinary urea excretion increased in rats given a lower quality protein. The purpose of present study was to determine whether the composition of dietary amino acids affects urea synthesis. Experiments were done on three groups of rats given diets containing a 10% gluten amino acid mix diet or 10% casein amino acid mix diet or 10% whole egg protein amino acids mix diet for 10 d. The urinary excretion of urea, the liver concentration of N-acetylglutamate, and the liver concentration of free serine, glutamic acids and alanine were greater in the group given the amino acid mix diet of lower quality. The fractional and absolute rates of protein synthesis in tissues declined with a decrease in quality of dietary amino acids. The hepatic concentration of ornithine and the activities of hepatic urea-cycle enzymes were not related to the urea excretion. These results suggest that the increased concentrations of amino acids and N-acetylglutamate seen in the liver of rats given the amino acid mix diets of lower quality are likely among the factors stimulating urea synthesis. The protein synthesis in tissues is at least partly related to hepatic concentrations of amino acids. The composition of dietary amino acids is likely to be one of the factors regulating urea synthesis when the quality of dietary protein is manipulated.

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

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

PubMed

Furuta, Chie; Murakami, Hitoshi

2018-01-01

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

GC-Content of Synonymous Codons Profoundly Influences Amino Acid Usage

PubMed Central

Li, Jing; Zhou, Jun; Wu, Ying; Yang, Sihai; Tian, Dacheng

2015-01-01

Amino acids typically are encoded by multiple synonymous codons that are not used with the same frequency. Codon usage bias has drawn considerable attention, and several explanations have been offered, including variation in GC-content between species. Focusing on a simple parameter—combined GC proportion of all the synonymous codons for a particular amino acid, termed GCsyn—we try to deepen our understanding of the relationship between GC-content and amino acid/codon usage in more details. We analyzed 65 widely distributed representative species and found a close association between GCsyn, GC-content, and amino acids usage. The overall usages of the four amino acids with the greatest GCsyn and the five amino acids with the lowest GCsyn both vary with the regional GC-content, whereas the usage of the remaining 11 amino acids with intermediate GCsyn is less variable. More interesting, we discovered that codon usage frequencies are nearly constant in regions with similar GC-content. We further quantified the effects of regional GC-content variation (low to high) on amino acid usage and found that GC-content determines the usage variation of amino acids, especially those with extremely high GCsyn, which accounts for 76.7% of the changed GC-content for those regions. Our results suggest that GCsyn correlates with GC-content and has impact on codon/amino acid usage. These findings suggest a novel approach to understanding the role of codon and amino acid usage in shaping genomic architecture and evolutionary patterns of organisms. PMID:26248983

Effects of alkali or acid treatment on the isomerization of amino acids.

PubMed

Ohmori, Taketo; Mutaguchi, Yuta; Doi, Katsumi; Ohshima, Toshihisa

2012-10-01

The effect of alkali treatment on the isomerization of amino acids was investigated. The 100×D/(D+L) values of amino acids from peptide increased with increase in the number of constituent amino acid residues. Furthermore, the N-terminal amino acid of a dipeptide was isomerized to a greater extent than the C-terminal residue. Copyright © 2012. Published by Elsevier B.V.

Comparative study on the composition of free amino acids and derivatives in the two botanical origins of an edible Chinese herb "Xiebai", i.e., Allium chinense G. Don and Allium macrostemon Bunge species.

PubMed

He, Quan; Huang, Shaohui; Wu, Yuehong; Zhang, Wenqi; Wang, Fanchao; Cao, Jiawei; Sheng, Qing; Liang, Zongsuo; Liu, Lili; Ou, Wen-Bin

2018-04-01

Xiebai is an edible Chinese herb with various health and therapeutic benefits. To evaluate its nutritional and health values, the free amino acids and derivatives of its two botanical origins (i.e., Allium chinense G. Don and Allium macrostemon Bunge) were isolated using a solvent extraction method and analyzed using automatic amino acid analysis and ultra-performance liquid chromatography-quadrupole-time of flight (UPLC-Q-TOF) mass spectrometry. Our data show that both plants contain abundant free amino acids, and the amount of total free amino acids in A. chinense G. Don is higher than that in A. macrostemon Bunge. The free amino acid compositions in the two plants are qualitatively similar, including nineteen proteinogenic and four non-proteinogenic amino acids. The identified proteinogenic amino acids include eight essential amino acids and five semi-essential amino acids. The sum of essential and semi-essential amino acids accounts for 64.9% and 69.7% of the total free amino acids of the two plants, respectively. The principal amino acids of both plants, from highest concentration to lowest concentration, are arginine, glutamine, glutamic acid, asparagine and serine. A. chinense G. Don is also rich in citrulline and lysine. In addition, two amino acid derivatives were identified from the two plants, i.e., the proline analog N‑methyl‑proline and the dipeptide H-Glu-Tyr-OH. For the first time, the presence of N‑methyl‑proline in the plants of the Allium genus and the presence of H-Glu-Tyr-OH in unprocessed food sources are reported. The influences of the identified substances on the flavor, nutrition and health values of Xiebai are discussed. Copyright © 2018 Elsevier Ltd. All rights reserved.

Distribution and enantiomeric composition of amino acids in the Murchison meteorite

NASA Technical Reports Server (NTRS)

Engel, M. H.; Nagy, B.

1982-01-01

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

Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides. Polypeptide vesicles by conformation-specific assembly. Ordered chiral macroporous hybrid silica-polypeptide composites

NASA Astrophysics Data System (ADS)

Bellomo, Enrico Giuseppe

2005-07-01

Aqueous cholesteric liquid crystals using uncharged rodlike polypeptides . The aqueous, lyotropic liquid-crystalline phase behavior of an alpha helical polypeptide, has been studied using optical microscopy and X-ray scattering. Solutions of optically pure polypeptide were found to form cholesteric liquid crystals at volume fractions that decreased with increasing average chain length. At very high volume fractions, the formation of a hexagonal mesophase was observed. The pitch of the cholesteric phase could be varied by a mixture of enantiomeric samples, where the pitch increased as the mixture approached equimolar. The cholesteric phases could be untwisted, using either magnetic field or shear flow, into nematic phases, which relaxed into cholesterics upon removal of field or shear. We have found that the phase diagram of this polypeptide in aqueous solution parallels that of poly(gamma-benzyl glutamate) in organic solvents, thus providing a useful system for liquid-crystal applications requiring water as solvent. Polypeptide vesicles by conformation-specific assembly. We have found that block copolymers composed of polypeptide segments provide significant advantages in controlling both the function and supramolecular structure of bioinspired self-assemblies. Incorporation of the stable chain conformations found in proteins into block copolymers was found to provide an additional element of control, beyond amphiphilicity and composition that defines self-assembled architecture. The abundance of functionality present in amino acids, and the ease by which they can be incorporated into these materials, also provides a powerful mechanism to impart block copolypeptides with function. This combination of structure and function work synergistically to enable significant advantages in the preparation of therapeutic agents as well as provide insight into design of self-assemblies beginning to approach the complexity of natural structures such as virus capsids. Ordered chiral macroporous hybrid silica-polypeptide composites. The mineralization of organic templates has been investigated as an effective way to control the size and structure of inorganic frameworks. Hybrid structures incorporating polypeptide with silica have been prepared and characterized using X-ray scattering, TGA, SEM and TEM. The results support the interaction between silica and polymer to form ordered chiral macroporous structures that can be easily controlled by polymer molecular weight and volume fraction.

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

37 CFR 1.822 - Symbols and format to be used for nucleotide and/or amino acid sequence data.

Code of Federal Regulations, 2011 CFR

2011-07-01

... for nucleotide and/or amino acid sequence data. 1.822 Section 1.822 Patents, Trademarks, and... Amino Acid Sequences § 1.822 Symbols and format to be used for nucleotide and/or amino acid sequence data. (a) The symbols and format to be used for nucleotide and/or amino acid sequence data shall...

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

USDA-ARS?s Scientific Manuscript database

The purpose of this study was to evaluate amino acids as natural antioxidants for frying. Twenty amino acids were added to soybean oil heated to 180 ºC, and the effects of amino acid structure on the antioxidant activity were investigated. Amino acids containing a thiol, a thioether, or an extra ami...

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.

New insights into the metabolism of aspartate-family amino acids in plant seeds.

PubMed

Wang, Wenyi; Xu, Mengyun; Wang, Guoping; Galili, Gad

2018-02-05

Aspartate-family amino acids. Aspartate (Asp)-family pathway, via several metabolic branches, leads to four key essential amino acids: Lys, Met, Thr, and Ile. Among these, Lys and Met have received the most attention, as they are the most limiting amino acid in cereals and legumes crops, respectively. The metabolic pathways of these four essential amino acids and their interactions with regulatory networks have been well characterized. Using this knowledge, extensive efforts have been devoted to augmenting the levels of these amino acids in various plant organs, especially seeds, which serve as the main source of human food and livestock feed. Seeds store a number of storage proteins, which are utilized as nutrient and energy resources. Storage proteins are composed of amino acids, to guarantee the continuation of plant progeny. Thus, understanding the seed metabolism, especially with respect to the accumulation of aspartate-derived amino acids Lys and Met, is a crucial factor for sustainable agriculture. In this review, we summarized the Asp-family pathway, with some new examples of accumulated Asp-family amino acids, particularly Lys and Met, in plant seeds. We also discuss the recent advances in understanding the roles of Asp-family amino acids during seed development.

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.

[Analysis of proteins, amino acids and inorganic elements in Holotrichia diomphalia from different areas].

PubMed

Cao, Wei; Liu, Dan; Zhang, Yi-Kai; Wang, Xiao-Yu; Chang, Yan-Rong; Yang, Qian; Wang, Si-Wang

2010-10-01

To analyze the content of proteins,amino acids and inorganic elements of Holotrichia diomphalia in different growing areas as the references for quality evaluation and reasonable application of them. The contents of proteins were determined using semi-micro Kjeldahl method. The contents of seventeen amino acids and inorganic elements were determined with amino acid analyzer and atomic absorption spectrometer and elemental analyzer, respectively. The contents of protein were 33.4%-44.4%, and that in Jiangxi were the highest in five different areas. There were seventeen kinds of amino acids in Holotrichia diomphalia. Among them, seven amino acids were essential to human life. The content of glutamic acid was the highest in seventeen amino acids. In inorganic elements, the content of Mg, Ca was higher in macroelements and Fe, Zn was higher in microelements. There are many kinds of necessary amino acids and inorganic elements for man kind in Holotrichia diomphalia. The contents of proteins, amino acids and inorganic elements have some difference in Holotrichia diomphalia of different growing areas.

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

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.

An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization

NASA Astrophysics Data System (ADS)

Chin, K. B.; Chi, I.; Pasalic, J.; Huang, C.-K.; Barge, Laura M.

2018-04-01

Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations <1 mM, however, the polar amino acid solution conductivity remained constant, suggesting poor chemical activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.

Amino Acid Concentrations in HIV-Infected Youth Compared to Healthy Controls and Associations with CD4 Counts and Inflammation.

PubMed

Ziegler, Thomas R; Judd, Suzanne E; Ruff, Joshua H; McComsey, Grace A; Eckard, Allison Ross

2017-07-01

Amino acids play critical roles in metabolism, cell function, body composition and immunity, but little data on plasma amino acid concentrations in HIV are available. We evaluated plasma amino acid concentrations and associations with CD4 counts and inflammatory biomarkers in HIV-infected youth. HIV-infected subjects with a high (≥500 cells/mm 3 ) and low (<500 cells/mm 3 ) current CD4 + T cell counts were compared to one another and to a matched healthy control group. Plasma concentrations of 19 amino acids were determined with an amino acid analyzer. Plasma levels of interleukin-6, tumor necrosis factor receptor-I, and soluble vascular cellular adhesion molecule-I were also measured. Seventy-nine HIV-infected subjects (40 and 39 with high and low CD4 + T cell counts, respectively) and 40 controls were included. There were no differences in amino acid concentrations between HIV-infected subjects with high or low CD4 + T cell counts. When combined, the HIV-infected group exhibited significantly lower median plasma concentrations compared to controls for total, essential, branched-chain and sulfur amino acids, as well as for 12 individual amino acids. Glutamate was the only amino acid that was higher in the HIV-infected group. There were no significant correlations between amino acid endpoints and inflammatory biomarkers for either HIV-infected group or controls. Plasma amino acid concentrations were lower in HIV-infected youth compared to healthy controls, regardless of immune status, while glutamate concentrations were elevated. These findings can inform future interventional studies designed to improve metabolic and clinical parameters influenced by amino acid nutriture.

An introductory study using impedance spectroscopy technique with polarizable microelectrode for amino acids characterization.

PubMed

Chin, K B; Chi, I; Pasalic, J; Huang, C-K; Barge, Laura M

2018-04-01

Portable, low power, yet ultra-sensitive life detection instrumentations are vital to future astrobiology flight programs at NASA. In this study, initial attempts to characterize amino acids in an aqueous environment by electrochemical impedance spectroscopy (EIS) using polarizable (blocking) electrodes in order to establish a means of detection via their electrical properties. Seven amino acids were chosen due to their scientific importance in demonstrating sensitivity levels in the range of part per billion concentration. Albeit more challenging in real systems of analyst mixtures, we found individual amino acids in aqueous environment do exhibit some degree of chemical and physical uniqueness to warrant characterization by EIS. The polar amino acids (Asp, Glu, and His) exhibited higher electrochemical activity than the non-polar amino acids (Ala, Gly, Val, and Leu). The non-polar amino acids (Gly and Ala) also exhibited unique electrical properties which appeared to be more dependent on physical characteristics such as molecular weight and structure. At concentrations above 1 mM where the amino acids play a more dominant transport role within the water, the conductivity was found to be more sensitive to concentrations. At lower concentrations <1 mM, however, the polar amino acid solution conductivity remained constant, suggesting poor chemical activity with water. As revealed by equivalent circuit modeling, the relaxation times showed a 1-2 order of magnitude difference between polar and non-polar amino acids. The pseudo-capacitance from EIS measurements on sample mixtures containing salt water and individual amino acids revealed the possibility for improvement in amino acid selectivity using gold nanoporous surface enhanced electrodes. This work establishes important methodologies for characterizing amino acids using EIS combined with microscale electrodes, supporting the case for instrumentation development for life detection and origin of life programs.

A Propensity for n-omega-Amino Acids in Thermally-Altered Antarctic Meteorites

NASA Technical Reports Server (NTRS)

Burton, Aaron S.; Elsila, Jamie E.; Callahan, Michael P.; Martin, Mildred G.; Glavin, Daniel P.; Johnson, Natasha M.; Dworkin, Jason P.

2012-01-01

Carbonaceous meteorites are known to contain a wealth of indigenous organic molecules, including amino acids, which suggests that these meteorites could have been an important source of prebiotic organic material during the origins of life on Earth and possibly elsewhere. We report the detection of extraterrestrial amino acids in thermally-altered type 3 CV and CO carbonaceous chondrites and ureilites recovered from Antarctica. The amino acid concentrations of the thirteen Antarctic meteorites were generally less abundant than in more amino acid-rich CI, CM, and CR carbonaceous chondrites that experienced much lower temperature aqueous alteration on their parent bodies. In contrast to low-temperature aqueously-altered meteorites that show complete structural diversity in amino acids formed predominantly by Strecker-cyanohydrin synthesis, the thermally-altered meteorites studied here are dominated by small, straight-chain, amine terminal (n-omega-amino) amino acids that are not consistent with Strecker formation. The carbon isotopic ratios of two extraterrestrial n-omega-amino acids measured in one of the CV chondrites are consistent with C-13-depletions observed previously in hydrocarbons produced by Fischer-Tropsch type reactions. The predominance of n-omega-amino acid isomers in thermally-altered meteorites hints at cosmochemical mechanisms for the preferential formation and preservation of a small subset of the possible amino acids.

Evidence from Meteorites for Multiple Possible Amino Acid Alphabets for the Origins of Life

NASA Technical Reports Server (NTRS)

Burton, A. S.; Elsila, J. E.; Callahan, M. P.; Glavin, D. P.; Dworkin, J. P.

2015-01-01

A key question for the origins of life is understanding which amino acids made up the first proteins synthesized during the origins of life. The canonical set of 20 - 22 amino acids used in proteins are all alpha-amino, alpha-hydrogen isomers that, nevertheless, show considerable variability in properties including size, hydrophobicity, and ionizability. Abiotic amino acid synthesis experiments such as Miller-Urey spark discharge reactions produce a set of up to 23 amino acids, depending on starting materials and reaction conditions, with significant abundances of both alpha- and non-alpha-amino acid isomers. These two sets of amino acids do not completely overlap; of the 23 spark discharge amino acids, only 11 are used in modern proteins. Furthermore, because our understanding of conditions on the early Earth are limited, it is unclear which set(s) of conditions employed in spark discharge or hydrothermal reactions are correct, leaving us with significant uncertainty about the amino acid alphabet available for the origins of life on Earth. Meteorites, the surviving remnants of asteroids and comets that fall to the Earth, offer the potential to study authentic samples of naturally-occurring abiotic chemistry, and thus can provide an alternative approach to constraining the amino acid library during the origins of life.

High-throughput quantitation of amino acids in rat and mouse biological matrices using stable isotope labeling and UPLC-MS/MS analysis.

PubMed

Takach, Edward; O'Shea, Thomas; Liu, Hanlan

2014-08-01

Quantifying amino acids in biological matrices is typically performed using liquid chromatography (LC) coupled with fluorescent detection (FLD), requiring both derivatization and complete baseline separation of all amino acids. Due to its high specificity and sensitivity, the use of UPLC-MS/MS eliminates the derivatization step and allows for overlapping amino acid retention times thereby shortening the analysis time. Furthermore, combining UPLC-MS/MS with stable isotope labeling (e.g., isobaric tag for relative and absolute quantitation, i.e., iTRAQ) of amino acids enables quantitation while maintaining sensitivity, selectivity and speed of analysis. In this study, we report combining UPLC-MS/MS analysis with iTRAQ labeling of amino acids resulting in the elution and quantitation of 44 amino acids within 5 min demonstrating the speed and convenience of this assay over established approaches. This chromatographic analysis time represented a 5-fold improvement over the conventional HPLC-MS/MS method developed in our laboratory. In addition, the UPLC-MS/MS method demonstrated improvements in both specificity and sensitivity without loss of precision. In comparing UPLC-MS/MS and HPLC-MS/MS results of 32 detected amino acids, only 2 amino acids exhibited imprecision (RSD) >15% using UPLC-MS/MS, while 9 amino acids exhibited RSD >15% using HPLC-MS/MS. Evaluating intra- and inter-assay precision over 3 days, the quantitation range for 32 detected amino acids in rat plasma was 0.90-497 μM, with overall mean intra-day precision of less than 15% and mean inter-day precision of 12%. This UPLC-MS/MS assay was successfully implemented for the quantitative analysis of amino acids in rat and mouse plasma, along with mouse urine and tissue samples, resulting in the following concentration ranges: 0.98-431 μM in mouse plasma for 32 detected amino acids; 0.62-443 μM in rat plasma for 32 detected amino acids; 0.44-8590μM in mouse liver for 33 detected amino acids; 0.61-1241 μM in mouse kidney for 37 detected amino acids; and 1.39-1,681 μM in rat urine for 34 detected amino acids. The utility of the assay was further demonstrated by measuring and comparing plasma amino acid levels between pre-diabetic Zucker diabetic fatty rats (ZDF/Gmi fa/fa) and their lean littermates (ZDF/Gmi fa/?). Significant differences (P<0.001) in 9 amino acid concentrations were observed, with the majority ranging from a 2- to 5-fold increase in pre-diabetic ZDF rats on comparison with ZDF lean rats, consistent with previous literature reports. Copyright © 2014 Elsevier B.V. All rights reserved.

The Use of Gel Electrophoresis to Study the Reactions of Activated Amino Acids with Oligonucleotides

NASA Technical Reports Server (NTRS)

Zieboll, Gerhard; Orgel, Leslie E.

1994-01-01

We have used gel electrophoresis to study the primary covalent addition of amino acids to oligonu-cleotides or their analogs and the subsequent addition of further molecules of the amino acids to generate peptides covalently linked to the oligonucleotides. We have surveyed the reactions of a variety of amino acids with the phosphoramidates derived from oligonucleotide 5 inches phosphates and ethylenediamine. We find that arginine and amino acids can interact with oligonucleotidesl through stacking interactions react most efficiently. D- and L-amino acids give indistinguishable families of products.

Analysis of charge transport in gels containing polyoxometallates using methods of different sensitivity to migration.

PubMed

Caban, Karolina; Lewera, Adam; Zukowska, Grazyna Z; Kulesza, Pawel J; Stojek, Zbigniew; Jeffrey, Kenneth R

2006-08-04

Two methods have been used for examination of transport of charge in gels soaked with DMF and containing dissolved polyoxometallates. The first method is based on the analysis of both Cottrellian and steady-state currents and therefore is capable of giving the concentration of the electroactive redox centres and their transport (diffusion-type) coefficient. The second method provides the real diffusion coefficients, i.e. transport coefficients free of migrational influence, for both the substrate and the product of the electrode reaction. Several gels based on poly(methyl methacrylate), with charged (addition of 1-acrylamido-2-methyl-2-propanesulphonic acid to the polymerization mixture) and uncharged chains, have been used in the investigation. The ratio obtained for the diffusion coefficient (second method) and transport coefficient (first method) was smaller for the gels containing charged polymer chains than for the gels with uncharged chains. In part these changes could be explained by the contribution of migration to the transport of polyoxomatallates in the gels. However, the impact of the changes in the polymer-channel capacity at the electrode surface while the electrode process proceeds was also considered. These structural changes should affect differently the methods based on different time domains.

Effect of hydrogen on void initiation in tensile test of carbon steel JIS-S25C

NASA Astrophysics Data System (ADS)

Sugawa, S.; Tsutsumi, N.; Oda, K.

2018-06-01

In order to investigate the effect of hydrogen on tensile fracture mechanism of a carbon steel, tensile tests were conducted. Pre-strain specimens (0%, 5% and 10%) were used to study the effect of hydrogen content, since saturated hydrogen content in specimens increases in increasing dislocation density. The tensile strength and the yield stress of hydrogen specimens were almost the same as uncharged. In contrast, the reduction of area of hydrogen charged specimens was smaller than that of uncharged. To reveal the reasons of decrease of the reduction of area, the fracture surface and longitudinal cross section near the fracture surface were observed. On the fracture surface of uncharged specimens, only dimples were observed. On the other hand, dimples and flat fracture surface were observed on the fracture surface of hydrogen charged. On the longitudinal cross section of hydrogen charged specimens, many voids were observed compared to uncharged. From these observations, it is showed that hydrogen gives a rise to the increase of voids and the hydrogen charged specimens break without sufficient necking, thus hydrogen makes the reduction of area smaller.

Amino acid fermentation at the origin of the genetic code.

PubMed

de Vladar, Harold P

2012-02-10

There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments 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.

Heterogeneous Distributions of Amino Acids Provide Evidence of Multiple Sources Within the Almahata Sitta Parent Body, Asteroid 2008 TC(sub 3)

NASA Technical Reports Server (NTRS)

Burton, Aaron S.; Glavin, Daniel P.; Callahan, Michael P.; Dworkin, Jason P.; Jenniskens, Peter; Shaddad, Muawia H.

2011-01-01

Two new fragments of the Almahata Sitta meteorite and a sample of sand from the related strewn field in the Nubian Desert, Sudan, were analyzed for two to six carbon aliphatic primary amino acids by ultrahigh performance liquid chromatography with UV-fluorescence detection and time-of-flight mass spectrometry (LC-FT/ToF-MS). The distribution of amino acids in fragment #25, an H5 ordinary chondrite, and fragment #27, a polymict ureilite, were compared with results from the previously analyzed fragment #4, also a polymict ureilite. All three meteorite fragments contain 180-270 parts-per-billion (ppb) of amino acids, roughly 1000-fold lower than the total amino acid abundance of the Murchison carbonaceous chondrite. All of the Almahata Sitta fragments analyzed have amino acid distributions that differ from the Nubian Desert sand, which primarily contains L-alpha-amino acids. In addition, the meteorites contain several amino acids that were not detected in the sand, indicating that many of the amino acids are extraterrestrial in origin. Despite their petrological differences, meteorite fragments #25 and #27 contain similar amino acid compositions; however, the distribution of amino acids in fragment #27 was distinct from those in fragment #4, even though both arc polymict ureilites from the same parent body. Unlike in CM2 and CR2/3 meteorites, there are low relative abundances of alpha-amino acids in the Almahata Sitta meteorite fragments, which suggest that Strecker-type chemistry was not a significant amino acid formation mechanism. Given the high temperatures that asteroid 2008 TC3 appears to have experienced and lack of evidence for aqueous alteration on the asteroid, it is possible that the extraterrestrial amino acids detected in Almahata Sitta were formed by Fischer-Tropsch/Haber-Bosch type gas-grain reactions at elevated temperatures.

Relative Amino Acid Composition Signatures of Organisms and Environments

PubMed Central

Moura, Alexandra; Savageau, Michael A.; Alves, Rui

2013-01-01

Background Identifying organism-environment interactions at the molecular level is crucial to understanding how organisms adapt to and change the chemical and molecular landscape of their habitats. In this work we investigated whether relative amino acid compositions could be used as a molecular signature of an environment and whether such a signature could also be observed at the level of the cellular amino acid composition of the microorganisms that inhabit that environment. Methodologies/Principal Findings To address these questions we collected and analyzed environmental amino acid determinations from the literature, and estimated from complete genomic sequences the global relative amino acid abundances of organisms that are cognate to the different types of environment. Environmental relative amino acid abundances clustered into broad groups (ocean waters, host-associated environments, grass land environments, sandy soils and sediments, and forest soils), indicating the presence of amino acid signatures specific for each environment. These signatures correlate to those found in organisms. Nevertheless, relative amino acid abundance of organisms was more influenced by GC content than habitat or phylogeny. Conclusions Our results suggest that relative amino acid composition can be used as a signature of an environment. In addition, we observed that the relative amino acid composition of organisms is not highly determined by environment, reinforcing previous studies that find GC content to be the major factor correlating to amino acid composition in living organisms. PMID:24204807

Relative amino acid composition signatures of organisms and environments.

PubMed

Moura, Alexandra; Savageau, Michael A; Alves, Rui

2013-01-01

Identifying organism-environment interactions at the molecular level is crucial to understanding how organisms adapt to and change the chemical and molecular landscape of their habitats. In this work we investigated whether relative amino acid compositions could be used as a molecular signature of an environment and whether such a signature could also be observed at the level of the cellular amino acid composition of the microorganisms that inhabit that environment. To address these questions we collected and analyzed environmental amino acid determinations from the literature, and estimated from complete genomic sequences the global relative amino acid abundances of organisms that are cognate to the different types of environment. Environmental relative amino acid abundances clustered into broad groups (ocean waters, host-associated environments, grass land environments, sandy soils and sediments, and forest soils), indicating the presence of amino acid signatures specific for each environment. These signatures correlate to those found in organisms. Nevertheless, relative amino acid abundance of organisms was more influenced by GC content than habitat or phylogeny. Our results suggest that relative amino acid composition can be used as a signature of an environment. In addition, we observed that the relative amino acid composition of organisms is not highly determined by environment, reinforcing previous studies that find GC content to be the major factor correlating to amino acid composition in living organisms.

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.

Survival of Amino Acids in Micrometeorites During Atmospheric Entry

NASA Technical Reports Server (NTRS)

Glavin, Daniel P.; Bada, Jeffrey L.

2003-01-01

The delivery of amino acids by micrometeorites to the early Earth during the period of heavy bombardment could have been a significant source of the Earth's prebiotic amino acid inventory provided that these organic compounds survived atmospheric entry heating. To investigate the sublimation of amino acids from a micrometeorite analog at elevated temperature, grains from the CM-type carbonaceous chondrite Murchison were heated to 550 C inside a glass sublimation apparatus (SA) under reduced pressure. The sublimed residue that had collected on the cold finger of the SA after heating was analyzed for amino acids by HPLC. We found that when the temperature of the meteorite reached approx. 150 C, a large fraction of the amino acid glycine had vaporized from the meteorite, recondensed onto the end of the SA cold finger, and survived as the rest of the grains heated to 550 C. alpha-Aminoisobutryic acid and isovaline, which are two of the most abundant non-protein amino acids in Murchison, did not sublime from the meteorite and were completely destroyed during the heating experiment. Our experimental results suggest that sublimation of glycine present in micrometeorite grains may provide a way for this amino acid to survive atmospheric entry heating at temperatures less than 550 C; all other amino acids apparently are destroyed. Key Words: Amino acids-Exogenous delivery-Micrometeorites-Sublimation.

Preference for and learning of amino acids in larval Drosophila

PubMed Central

Kudow, Nana; Miura, Daisuke; Schleyer, Michael; Toshima, Naoko; Gerber, Bertram

2017-01-01

ABSTRACT Relative to other nutrients, less is known about how animals sense amino acids and how behaviour is organized accordingly. This is a significant gap in our knowledge because amino acids are required for protein synthesis − and hence for life as we know it. Choosing Drosophila larvae as a case study, we provide the first systematic analysis of both the preference behaviour for, and the learning of, all 20 canonical amino acids in Drosophila. We report that preference for individual amino acids differs according to the kind of amino acid, both in first-instar and in third-instar larvae. Our data suggest that this preference profile changes across larval instars, and that starvation during the third instar also alters this profile. Only aspartic acid turns out to be robustly attractive across all our experiments. The essentiality of amino acids does not appear to be a determinant of preference. Interestingly, although amino acids thus differ in their innate attractiveness, we find that all amino acids are equally rewarding. Similar discrepancies between innate attractiveness and reinforcing effect have previously been reported for other tastants, including sugars, bitter substances and salt. The present analyses will facilitate the ongoing search for the receptors, sensory neurons, and internal, homeostatic amino acid sensors in Drosophila. PMID:28193602

Presynaptic (Type III) cells in mouse taste buds sense sour (acid) taste.

PubMed

Huang, Yijen A; Maruyama, Yutaka; Stimac, Robert; Roper, Stephen D

2008-06-15

Taste buds contain two types of cells that directly participate in taste transduction - receptor (Type II) cells and presynaptic (Type III) cells. Receptor cells respond to sweet, bitter and umami taste stimulation but until recently the identity of cells that respond directly to sour (acid) tastants has only been inferred from recordings in situ, from behavioural studies, and from immunostaining for putative sour transduction molecules. Using calcium imaging on single isolated taste cells and with biosensor cells to identify neurotransmitter release, we show that presynaptic (Type III) cells specifically respond to acid taste stimulation and release serotonin. By recording responses in cells isolated from taste buds and in taste cells in lingual slices to acetic acid titrated to different acid levels (pH), we also show that the active stimulus for acid taste is the membrane-permeant, uncharged acetic acid moiety (CH(3)COOH), not free protons (H(+)). That observation is consistent with the proximate stimulus for acid taste being intracellular acidification, not extracellular protons per se. These findings may also have implications for other sensory receptors that respond to acids, such as nociceptors.

A model of proteolysis and amino acid biosynthesis for Lactobacillus delbrueckii subsp. bulgaricus in whey.

PubMed

Liu, Enuo; Zheng, Huajun; Hao, Pei; Konno, Tomonobu; Yu, Yao; Kume, Hisae; Oda, Munehiro; Ji, Zai-Si

2012-12-01

Lactobacillus delbrueckii subsp. bulgaricus 2038 (L. bulgaricus 2038) is a bacterium that is used as a starter for dairy products by Meiji Co., Ltd of Japan. Culturing L. bulgaricus 2038 with whey as the sole nitrogen source results in a shorter lag phase than other milk proteins under the same conditions (carbon source, minerals, and vitamins). Microarray results of gene expression revealed characteristics of amino acid anabolism with whey as the nitrogen source and established a model of proteolysis and amino acid biosynthesis for L. bulgaricus. Whey peptides and free amino acids are readily metabolized, enabling rapid entry into the logarithmic growth phase. The oligopeptide transport system is the primary pathway for obtaining amino acids. Amino acid biosynthesis maintains the balance between amino acids required for cell growth and the amount obtained from environment. The interconversion of amino acids is also important for L. bulgaricus 2038 growth.

Absorption from a mixture of seventeen free amino acids by the isolated small intestine of the rat.

PubMed Central

Gardner, M L

1976-01-01

Absorption and secretion from a mixture of seventeen free amino acids has been measured in isolated perfused rat small intestine. 2. The absorption rate of an amino acid from this mixture is proportional to its concentration in the perfusate and independent of its chemical constitution. The constant of proportionality is the same as that previously observed when the perfusate contained peptides as well as amino acids. 3. Amino acids are concentrated, on average, sixfold during passage across the mucosa, and the free amino acid composition of the secretion into the tissue fluid is very similar to that of the luminal perfusate. 4. Peptides do not appear to be added to the tissue fluid during absorption of free amino acids. 5. It is concluded that the mechanisms for absorption of free amino acids are in general independent of those for absorption of peptides. PMID:1255532

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.

Gross and true ileal digestible amino acid contents of several animal body proteins and their hydrolysates.

PubMed

Cui, J; Chong, B; Rutherfurd, S M; Wilkinson, B; Singh, H; Moughan, P J

2013-07-01

Amino acid compositions of ovine muscle, ovine myofibrillar protein, ovine spleen, ovine liver, bovine blood plasma, bovine blood globulins and bovine serum albumin and the amino acid compositions and in vivo (laboratory rat) true ileal amino acid digestibilities of hydrolysates (sequential hydrolysis with Neutrase, Alcalase and Flavourzyme) of these protein sources were determined. True ileal amino acid digestibility differed (P<0.05) among the seven protein hydrolysates. The ovine myofibrillar protein and liver hydrolysates were the most digestible, with a mean true ileal digestibility across all amino acids of 99%. The least digestible protein hydrolysate was bovine serum albumin with a comparable mean true ileal digestibility of 93%. When the digestible amino acid contents were expressed as proportions relative to lysine, considerable differences, across the diverse protein sources, were found in the pattern of predicted absorbed amino acids. Copyright © 2013 Elsevier Ltd. All rights reserved.

Antioxidative Categorization of Twenty Amino Acids Based on Experimental Evaluation.

PubMed

Xu, Naijin; Chen, Guanqun; Liu, Hui

2017-11-27

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

Stereoconversion of amino acids and peptides in uryl-pendant binol schiff bases.

PubMed

Park, Hyunjung; Nandhakumar, Raju; Hong, Jooyeon; Ham, Sihyun; Chin, Jik; Kim, Kwan Mook

2008-01-01

(S)-2-Hydroxy-2'-(3-phenyluryl-benzyl)-1,1'-binaphthyl-3-carboxaldehyde (1) forms Schiff bases with a wide range of nonderivatized amino acids, including unnatural ones. Multiple hydrogen bonds, including resonance-assisted ones, fix the whole orientation of the imine and provoke structural rigidity around the imine C==N bond. Due to the structural difference and the increase in acidity of the alpha proton of the amino acid, the imine formed with an L-amino acid (1-l-aa) is converted into the imine of the D-amino acid (1-D-aa), with a D/L ratio of more than 10 for most amino acids at equilibrium. N-terminal amino acids in dipeptides are also predominantly epimerized to the D form upon imine formation with 1. Density functional theory calculations show that 1-D-Ala is more stable than 1-L-Ala by 1.64 kcal mol(-1), a value that is in qualitative agreement with the experimental result. Deuterium exchange of the alpha proton of alanine in the imine form was studied by (1)H NMR spectroscopy and the results support a stepwise mechanism in the L-into-D conversion rather than a concerted one; that is, deprotonation and protonation take place in a sequential manner. The deprotonation rate of L-Ala is approximately 16 times faster than that of D-Ala. The protonation step, however, appears to favor L-amino acid production, which prevents a much higher predominance of the D form in the imine. Receptor 1 and the predominantly D-form amino acid can be recovered from the imine by simple extraction under acidic conditions. Hence, 1 is a useful auxiliary to produce D-amino acids of industrial interest by the conversion of naturally occurring L-amino acids or relatively easily obtainable racemic amino acids.

More than just sugar: allocation of nectar amino acids and fatty acids in a Lepidopteran.

PubMed

Levin, Eran; McCue, Marshall D; Davidowitz, Goggy

2017-02-08

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, and metabolic demands. In addition to sugar, flower nectars contain two macronutrients-amino acids and fatty acids. We created artificial nectars spiked with 13 C-labelled amino acids and fatty acids and fed these to adult moths (Manduca sexta: Sphingidae) to understand how they allocate these nutrients among competing sinks (reproduction, somatic tissue, and metabolic fuel). We found that both essential and non-essential amino acids were allocated to eggs and flight muscles and were still detectable in early-instar larvae. Parental-derived essential amino acids were more conserved in the early-instars than non-essential amino acids. All amino acids were used as metabolic fuel, but the non-essential amino acids were oxidized at higher rates than essential amino acids. Surprisingly, the nectar fatty acids were not vertically transferred to offspring, but were readily used as a metabolic fuel by the moth, minimizing losses of endogenous nutrient stores. We conclude that the non-carbohydrate components of nectar may play important roles in both reproductive success and survival of these nectar-feeding animals. © 2017 The Author(s).

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.

More than just sugar: allocation of nectar amino acids and fatty acids in a Lepidopteran

PubMed Central

McCue, Marshall D.; Davidowitz, Goggy

2017-01-01

The ability to allocate resources, even when limited, is essential for survival and fitness. We examine how nutrients that occur in minute amounts are allocated among reproductive, somatic, and metabolic demands. In addition to sugar, flower nectars contain two macronutrients—amino acids and fatty acids. We created artificial nectars spiked with 13C-labelled amino acids and fatty acids and fed these to adult moths (Manduca sexta: Sphingidae) to understand how they allocate these nutrients among competing sinks (reproduction, somatic tissue, and metabolic fuel). We found that both essential and non-essential amino acids were allocated to eggs and flight muscles and were still detectable in early-instar larvae. Parental-derived essential amino acids were more conserved in the early-instars than non-essential amino acids. All amino acids were used as metabolic fuel, but the non-essential amino acids were oxidized at higher rates than essential amino acids. Surprisingly, the nectar fatty acids were not vertically transferred to offspring, but were readily used as a metabolic fuel by the moth, minimizing losses of endogenous nutrient stores. We conclude that the non-carbohydrate components of nectar may play important roles in both reproductive success and survival of these nectar-feeding animals. PMID:28148746

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.

Dog bites man or man bites dog? The enigma of the amino acid conjugations

PubMed Central

Beyoğlu, Diren; Smith, Robert L.; Idle, Jeffrey R.

2012-01-01

The proposition posed is that the value of amino acid conjugation to the organism is not, as in the traditional view, to use amino acids for the detoxication of aromatic acids. Rather, the converse is more likely, to use aromatic acids that originate from the diet and gut microbiota to assist in the regulation of body stores of amino acids, such as glycine, glutamate, and, in certain invertebrates, arginine, that are key neurotransmitters in the CNS. As such, the amino acid conjugations are not so much detoxication reactions, rather they are homeostatic and neuroregulatory processes. Experimental data have been culled in support of this hypothesis from a broad range of scientific and clinical literature. Such data include the low detoxication value of amino acid conjugations and the Janus nature of certain amino acids that are both neurotransmitters and apparent conjugating agents. Amino acid scavenging mechanisms in blood deplete brain amino acids. Amino acids glutamate and glycine when trafficked from brain are metabolized to conjugates of aromatic acids in hepatic mitochondria and then irreversibly excreted into urine. This process is used clinically to deplete excess nitrogen in cases of urea cycle enzymopathies through excretion of glycine or glutamine as their aromatic acid conjugates. Untoward effects of high-dose phenylacetic acid surround CNS toxicity. There appears to be a relationship between extent of glycine scavenging by benzoic acid and psychomotor function. Glycine and glutamine scavenging by conjugation with aromatic acids may have important psychosomatic consequences that link diet to health, wellbeing, and disease. PMID:22227274

37 CFR 1.822 - Symbols and format to be used for nucleotide and/or amino acid sequence data.

Code of Federal Regulations, 2014 CFR

2014-07-01

... base or modified or unusual amino acid may be presented in a given sequence as the corresponding unmodified base or amino acid if the modified base or modified or unusual amino acid is one of those listed... the Feature section. Otherwise, each occurrence of a base or amino acid not appearing in WIPO Standard...

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

PubMed

Matsumoto, Hikaru; Ikoma, Yoshinori

2012-10-03

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

The effect of amino acid infusion on anesthesia-induced hypothermia in muscle atrophy model rats.

PubMed

Kanazawa, Masahiro; Ando, Satoko; Tsuda, Michio; Suzuki, Toshiyasu

2010-01-01

An infusion of amino acids stimulates heat production in skeletal muscle and then attenuates the anesthesia-induced hypothermia. However, in a clinical setting, some patients have atrophic skeletal muscle caused by various factors. The present study was therefore conducted to investigate the effect of amino acids on the anesthesia-induced hypothermia in the state of muscle atrophy. As the muscle atrophy model, Sprague-Dawley rats were subjected to hindlimb immobilization for 2 wk. Normal rats and atrophy model rats were randomly assigned to one of the two treatment groups: saline or amino acids (n=8 for each group). Test solutions were administered intravenously to the rats under sevoflurane anesthesia for 180 min, and the rectal temperature was measured. Plasma samples were collected for measurement of insulin, blood glucose, and free amino acids. The rectal temperature was significantly higher in the normal-amino acid group than in the muscle atrophy-amino acid group from 75 to 180 min. The plasma insulin level was significantly higher in the rats given amino acids than in the rats given saline in both normal and model groups. In the rats given amino acids, plasma total free amino acid concentration was higher in the model group than in the normal group. These results indicate that skeletal muscle plays an important role in changes in body temperature during anesthesia and the effect of amino acids on anesthesia-induced hypothermia decreases in the muscle atrophy state. In addition, intravenous amino acids administration during anesthesia induces an increase in the plasma insulin level.

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.

Amino Acids Regulate Transgene Expression in MDCK Cells

PubMed Central

Torrente, Marta; Guetg, Adriano; Sass, Jörn Oliver; Arps, Lisa; Ruckstuhl, Lisa; Camargo, Simone M. R.; Verrey, François

2014-01-01

Gene expression and cell growth rely on the intracellular concentration of amino acids, which in metazoans depends on extracellular amino acid availability and transmembrane transport. To investigate the impact of extracellular amino acid concentrations on the expression of a concentrative amino acid transporter, we overexpressed the main kidney proximal tubule luminal neutral amino acid transporter B0AT1-collectrin (SLC6A19-TMEM27) in MDCK cell epithelia. Exogenously expressed proteins co-localized at the luminal membrane and mediated neutral amino acid uptake. However, the transgenes were lost over few cell culture passages. In contrast, the expression of a control transgene remained stable. To test whether this loss was due to inappropriately high amino acid uptake, freshly transduced MDCK cell lines were cultivated either with physiological amounts of amino acids or with the high concentration found in standard cell culture media. Expression of exogenous transporters was unaffected by physiological amino acid concentration in the media. Interestingly, mycoplasma infection resulted in a significant increase in transgene expression and correlated with the rapid metabolism of L-arginine. However, L-arginine metabolites were shown to play no role in transgene expression. In contrast, activation of the GCN2 pathway revealed by an increase in eIF2α phosphorylation may trigger transgene derepression. Taken together, high extracellular amino acid concentration provided by cell culture media appears to inhibit the constitutive expression of concentrative amino acid transporters whereas L-arginine depletion by mycoplasma induces the expression of transgenes possibly via stimulation of the GCN2 pathway. PMID:24797296

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 amino acids in these samples. However, the presence of the non-proteinogenic amino acids such as AIB and β-ABA suggests the possibility of some contribution from exogenous sources. We did not observe a correlation of amino acid content with proximity to the Apollo 17 lunar module, implying that lunar module exhaust was not a primary source of amino acid precursors. Solar-wind-implanted precursors such as HCN also appear to be at most a minor contributor, given a lack of correlation between amino acid content and soil maturity (as measured by Is/FeO ratio) and the differences between the δ13C values of the amino acids and the solar wind.

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

PubMed Central

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

2016-01-01

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

Quercetin inhibits hexose transport in a human diploid fibroblast

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

Salter, D.W.; Custead-Jones, S.; Cook, J.S.

1978-01-01

The flavonol quercetin, a phloretin analog, inhibits transport of 2-deoxyglucose and 3-O-methylglucose in a cultured human diploid fibroblast. This inhibition is related to transport itself and not to the reported effects of flavonoids on membrane-bound ATPases. From concentration-inhibition curves at several pH's we conclude that uncharged (acid) quercetin (pH = 7.65) is the inhibitory form of the molecule (K/sub I/ = 10 ..mu..m). Quercetin, unlike phloretin, is rapidly degraded in 0.1 N NaOH; the degradation products are weakly inhibitory to hexose transport.

Comet impacts and chemical evolution on the bombarded earth

NASA Technical Reports Server (NTRS)

Oberbeck, Verne R.; Aggarwal, Hans

1992-01-01

Amino acids yields for previously published shock tube experiments are used with minimum Cretaceous-Tertiary (K/T) impactor mass and comet composition to predict AIB amino acid K/T boundary sediment column density. The inferred initial concentration of all amino acids in the K/T sea and in similar primordial seas just after 10 km comet impacts would have been at least 10 exp -7 M. However, sinks for amino acids must also be considered in calculating amino acid concentrations after comet impacts and in assessing the contribution of comets to the origin of life. The changing concentration of cometary amino acids due to ultraviolet light is compared with the equilibrium concentration of amino acids produced in the sea from corona discharge in the atmosphere, deposition in water, and degradation by ultraviolet light. Comets could have been more important than endogenous agents for initial evolution of amino acids. Sites favorable for chemical evolution of amino acids are examined, and it is concluded that chemical evolution could have occurred at or above the surface even during periods of intense bombardment of earth before 3.8 billion years ago.

Impact contribution of prebiotic reactants to Earth

NASA Technical Reports Server (NTRS)

Aggarwal, Hans R.

1992-01-01

It is proposed that the AIB amino acid at the K/T boundary were synthesized during entry of a comet. However, whether they were synthesized or supplied directly from space, the concentration of amino acids in the shallow K/T sea would have been about 10(exp -7) M. It is probable that clays were the dominant sinks for the amino acids in the K/T sea and in the primordial ocean. Because clay removed amino acids from sea water quickly, the amino acid contribution must be studied from individual comets in order to evaluate the effectiveness of comets for chemical evolution. Such an evaluation shows that comets would have produced amino acid concentration higher than equilibrium concentrations of amino acid from corona discharge at all times preceding the age of the oldest fossils. The perferred sites for chemical evolution of cometary amino acids are in cloud drops and tide pools where the concentration of amino acids would have been the highest. Life could have originated at the surface even during periods of intense bombardment of the earth before 3.8 billion years ago.

Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories

NASA Technical Reports Server (NTRS)

Elsila, Jamie E.; Aponte, Jose C.; Blackmond, Donna G.; Burton, Aaron S.; Dworkin, Jason P.; Glavin, Daniel P.

2016-01-01

The analysis of amino acids in meteorites dates back over 50 years; however, it is only in recent years that research has expanded beyond investigations of a narrow set of meteorite groups (exemplied by the Murchison meteorite) into meteorites of other types and classes. These new studies have shown a wide diversity in the abundance and distribution of amino acids across carbonaceous chondrite groups, highlighting the role of parent body processes and composition in the creation, preservation, or alteration of amino acids. Although most chiral amino acids are racemic in meteorites, the enantiomeric distribution of some amino acids, particularly of the nonprotein amino acid isovaline, has also been shown to vary both within certain meteorites and across carbonaceous meteorite groups. Large -enantiomeric excesses of some extraterrestrial protein amino acids (up to 60) have also been observed in rare cases and point to nonbiological enantiomeric enrichment processes prior to the emergence of life. In this Outlook, we review these recent meteoritic analyses, focusing on variations in abundance, structural distributions, and enantiomeric distributions of amino acids and discussing possible explanations for these observations and the potential for future work.

Extraordinarily Adaptive Properties of the Genetically Encoded Amino Acids

PubMed Central

Ilardo, Melissa; Meringer, Markus; Freeland, Stephen; Rasulev, Bakhtiyor; Cleaves II, H. James

2015-01-01

Using novel advances in computational chemistry, we demonstrate that the set of 20 genetically encoded amino acids, used nearly universally to construct all coded terrestrial proteins, has been highly influenced by natural selection. We defined an adaptive set of amino acids as one whose members thoroughly cover relevant physico-chemical properties, or “chemistry space.” Using this metric, we compared the encoded amino acid alphabet to random sets of amino acids. These random sets were drawn from a computationally generated compound library containing 1913 alternative amino acids that lie within the molecular weight range of the encoded amino acids. Sets that cover chemistry space better than the genetically encoded alphabet are extremely rare and energetically costly. Further analysis of more adaptive sets reveals common features and anomalies, and we explore their implications for synthetic biology. We present these computations as evidence that the set of 20 amino acids found within the standard genetic code is the result of considerable natural selection. The amino acids used for constructing coded proteins may represent a largely global optimum, such that any aqueous biochemistry would use a very similar set. PMID:25802223

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.

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

PubMed

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

2017-04-15

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

The P9 peptide sidechain specificity of I-Ad.

PubMed

Bartnes, K; Li, X; Briand, J P; Travers, P J; Hannestad, K

1999-12-01

The murine MHC class II variant I-Ad confers susceptibility to herpes simplex virus (HSV)-induced keratitis and relative protection against type 1 diabetes mellitus. The association to these autoimmune diseases appears to be largely determined by the peptide sidechain specificity of the P9 pocket, which we therefore have analyzed in detail. Assessment of T-cell responses and I-Ad binding capacity of position 446-substituted analogs of an IgG2a allotype b (IgG2a(b)) heavy chain peptide demonstrates that engagement of the P9 pocket is crucial for effective peptide presentation. Sidechain size rather than charge decides the capacity to engage the P9 pocket. Thus, small, uncharged sidechains are accepted, whereas acidic and aromatic amino acids as well as lysine and arginine are disfavored. The specificity of the P9 pocket of I-Ad (serine beta57) is distinct from that of the diabetes-associated I-Ag7 (aspartic acid beta57), supporting the contention that the polymorphism at residue beta57 influences diabetes susceptibility via P9-specific effects on the repertoires of self peptides presented to T cells. Furthermore, the data rationalize the susceptibility to HSV-induced keratitis conferred by the a and the protection conferred by the b allotypes of the IgG2a heavy chain. Keratitogenic T cells, which cross-react with the viral UL6 protein and a corneal antigen, are silenced in IgG2a(b) mice because of antigenic mimicry with gamma2a(b) 435-451. Our finding that the lysine P9 residue of the corresponding gamma2a(a) allopeptide precludes high-affinity binding to I-Ad indicates that the susceptibility of IgG2a(a) mice reflects inefficient thymic presentation of autologous IgG2a and thus failure to purge the T-cell repertoire of the pathogenic clones.

The Nitrogen Moieties of Dietary Nonessential Amino Acids Are Distinctively Metabolized in the Gut and Distributed to the Circulation in Rats.

PubMed

Nakamura, Hidehiro; Kawamata, Yasuko; Kuwahara, Tomomi; Sakai, Ryosei

2017-08-01

Background: Although previous growth studies in rodents have indicated the importance of dietary nonessential amino acids (NEAAs) as nitrogen sources, individual NEAAs have different growth-promoting activities. This phenomenon might be attributable to differences in the nitrogen metabolism of individual NEAAs. Objective: The aim of this study was to compare nitrogen metabolism across dietary NEAAs with the use of their 15 N isotopologues. Methods: Male Fischer rats (8 wk old) were given 1.0 g amino acid-defined diets containing either 15 N-labeled glutamate, glutamine (amino or amide), aspartate, alanine, proline, glycine, or serine hourly for 5-6 h. Then, steady-state amino acid concentrations and their 15 N enrichments in the gut and in portal and arterial plasma were measured by an amino acid analyzer and LC tandem mass spectrometry, respectively. Results: The intestinal 15 N distribution and portal-arterial balance of 15 N metabolites indicated that most dietary glutamate nitrogen (>90% of dietary input) was incorporated into various amino acids, including alanine, proline, and citrulline, in the gut. Dietary aspartate nitrogen, alanine nitrogen, and amino nitrogen of glutamine were distributed similarly to other amino acids both in the gut and in the circulation. In contrast, incorporation of the nitrogen moieties of dietary proline, serine, and glycine into other amino acids was less than that of other NEAAs, although interconversion between serine and glycine was very active. Cluster analysis of 15 N enrichment data also indicated that dietary glutamate nitrogen, aspartate nitrogen, alanine nitrogen, and the amino nitrogen of glutamine were distributed similarly to intestinal and circulating amino acids. Further, the analysis revealed close relations between intestinal and arterial 15 N enrichment for each amino acid. The steady-state 15 N enrichment of arterial amino acids indicated that substantial amounts of circulating amino acid nitrogen are derived from dietary NEAAs. Conclusions: The present results revealed similarities and differences among NEAAs in terms of their intestinal nitrogen metabolism in rats and indicated substantial entry of dietary NEAA nitrogen into circulating amino acid nitrogen, presumably primarily through metabolism in the gut. © 2017 American Society for Nutrition.

40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

Code of Federal Regulations, 2010 CFR

2010-07-01

... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo...

40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

Code of Federal Regulations, 2011 CFR

2011-07-01

... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo...

High hydrostatic pressure increases amino acid requirements in the piezo-hyperthermophilic archaeon Thermococcus barophilus.

PubMed

Cario, Anaïs; Lormières, Florence; Xiang, Xiao; Oger, Philippe

2015-11-01

We have established a defined growth medium for the piezophilic hyperthermophilic archaeon Thermococcus barophilus, which allows growth yields of ca. 10(8) cells/ml under both atmospheric and high hydrostatic pressure. Our results demonstrate a major impact of hydrostatic pressure on amino acid metabolism, with increases from 3 amino acids required at atmospheric pressure to 17 at 40 MPa. We observe in T. barophilus and other Thermococcales a similar discrepancy between the presence/absence of amino acid synthesis pathways and amino acid requirements, which supports the existence of alternate, but yet unknown, amino acid synthesis pathways, and may explain the low number of essential amino acids observed in T. barophilus and other Thermococcales. T. barophilus displays a strong metabolic preference for organic polymers such as polypeptides and chitin, which may constitute a more readily available resource of carbon and energy in situ in deep-sea hydrothermal vents. We hypothesize that the low energy yields of fermentation of organic polymers, together with energetic constraints imposed by high hydrostatic pressure, may render de novo synthesis of amino acids ecologically unfavorable. Induction of this metabolic switch to amino acid recycling can explain the requirement for non-essential amino acids by Thermococcales for efficient growth in defined medium. Copyright © 2015 Institut Pasteur. Published by Elsevier Masson SAS. All rights reserved.

Amino Acids That Centrally Influence Blood Pressure and Regional Blood Flow in Conscious Rats

PubMed Central

Takemoto, Yumi

2012-01-01

Functional roles of amino acids have increasingly become the focus of research. This paper summarizes amino acids that influence cardiovascular system via the brain of conscious rats. This paper firstly describes why amino acids are selected and outlines how the brain regulates blood pressure and regional blood flow. This section includes a concise history of amino acid neurotransmitters in cardiovascular research and summarizes brain areas where chemical stimulations produce blood pressure changes mainly in anesthetized animals. This is followed by comments about findings regarding several newly examined amino acids with intracisternal stimulation in conscious rats that produce changes in blood pressure. The same pressor or depressor response to central amino acid stimulations can be produced by distinct mechanisms at central and peripheral levels, which will be briefly explained. Thereafter, cardiovascular actions of some of amino acids at the mechanism level will be discussed based upon findings of pharmacological and regional blood flow measurements. Several examined amino acids in addition to the established neurotransmitter amino acids appear to differentially activate brain structures to produce changes in blood pressure and regional blood flows. They may have physiological roles in the healthy brain, but pathological roles in the brain with cerebral vascular diseases such as stroke where the blood-brain barrier is broken. PMID:22690328

Impaired nutrient signaling and body weight control in a Na+ neutral amino acid cotransporter (Slc6a19)-deficient mouse.

PubMed

Bröer, Angelika; Juelich, Torsten; Vanslambrouck, Jessica M; Tietze, Nadine; Solomon, Peter S; Holst, Jeff; Bailey, Charles G; Rasko, John E J; Bröer, Stefan

2011-07-29

Amino acid uptake in the intestine and kidney is mediated by a variety of amino acid transporters. To understand the role of epithelial neutral amino acid uptake in whole body homeostasis, we analyzed mice lacking the apical broad-spectrum neutral (0) amino acid transporter B(0)AT1 (Slc6a19). A general neutral aminoaciduria was observed similar to human Hartnup disorder which is caused by mutations in SLC6A19. Na(+)-dependent uptake of neutral amino acids into the intestine and renal brush-border membrane vesicles was abolished. No compensatory increase of peptide transport or other neutral amino acid transporters was detected. Mice lacking B(0)AT1 showed a reduced body weight. When adapted to a standard 20% protein diet, B(0)AT1-deficient mice lost body weight rapidly on diets containing 6 or 40% protein. Secretion of insulin in response to food ingestion after fasting was blunted. In the intestine, amino acid signaling to the mammalian target of rapamycin (mTOR) pathway was reduced, whereas the GCN2/ATF4 stress response pathway was activated, indicating amino acid deprivation in epithelial cells. The results demonstrate that epithelial amino acid uptake is essential for optimal growth and body weight regulation.

Amino acid concentrations in the nectars of Southern African bird-pollinated flowers, especially aloe and erythrina.

PubMed

Nicolson, Susan W

2007-09-01

Amino acids in nectar have received less attention than the more abundant sugars. The dilute nectars of 32 species of southern African plants that are pollinated by passerine birds were analyzed by HPLC, and the effect of pollen contamination and the variation among inflorescences and plants were also examined. Aloe marlothii and some Erythrina species were found to have high total amino acid concentrations, sometimes exceeding 100 mM. Other Aloe species, as well as Greyia, Strelitzia, Schotia, Cotyledon, and Melianthus, had low nectar amino acid concentrations. Total amino acid concentrations varied much more than the sugar concentrations of these nectars as measured with a refractometer. Pollen contamination, previously claimed to be a major source of error in the measurement of nectar amino acids, had no effect on amino acids in the nectar of A. marlothii. Variation among inflorescences of Erythrina lysistemon was greater than that among trees, and most of the variation was because of relatively abundant nonessential amino acids such as asparagine and glutamine. High amino acid concentrations, especially in 'dilute' nectars, represent a substantial contribution of nonsugar solutes to 'sugar' concentrations measured with a refractometer. Amino acids in nectar may contribute to the nitrogen requirements of bird pollinators.

Biotransformation of β-keto nitriles to chiral (S)-β-amino acids using nitrilase and ω-transaminase.

PubMed

Mathew, Sam; Nadarajan, Saravanan Prabhu; Sundaramoorthy, Uthayasuriya; Jeon, Hyunwoo; Chung, Taeowan; Yun, Hyungdon

2017-04-01

To enzymatically synthesize enantiomerically pure β-amino acids from β-keto nitriles using nitrilase and ω-transaminase. An enzyme cascade system was designed where in β-keto nitriles are initially hydrolyzed to β-keto acids using nitrilase from Bradyrhizobium japonicum and subsequently β-keto acids were converted to β-amino acids using ω-transaminases. Five different ω-transaminases were tested for this cascade reaction, To enhance the yields of β-amino acids, the concentrations of nitrilase and amino donor were optimized. Using this enzymatic reaction, enantiomerically pure (S)-β-amino acids (ee > 99%) were generated. As nitrilase is the bottleneck in this reaction, molecular docking analysis was carried out to depict the poor affinity of nitrilase towards β-keto acids. A novel enzymatic route to generate enantiomerically pure aromatic (S)-β-amino acids from β-keto nitriles is demonstrated for the first time.

Studies related to primitive chemistry. A proton and nitrogen-14 nuclear magnetic resonance amino acid and nucleic acid constituents and a and their possible relation to prebiotic

NASA Technical Reports Server (NTRS)

Manatt, S. L.; Cohen, E. A.; Shiller, A. M.; Chan, S. I.

1973-01-01

Preliminary proton nuclear magnetic resonance (NMR) studies were made to determine the applicability of this technique for the study of interactions between monomeric and polymeric amino acids with monomeric nucleic acid bases and nucleotides. Proton NMR results for aqueous solutions (D2O) demonstrated interactions between the bases cytosine and adenine and acidic and aromatic amino acids. Solutions of 5'-AMP admixed with amino acids exhibited more complex behavior but stacking between aromatic rings and destacking at high amino acids concentration was evident. The multisite nature of 5'-AMP was pointed out. Chemical shift changes for adenine and 5'-AMP with three water soluble polypeptides demonstrated that significant interactions exist. It was found that the linewidth-pH profile of each amino acid is unique. It is concluded that NMR techniques can give significant and quantitative data on the association of amino acid and nucleic acid constituents.

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.

Chemical evolution. XXI - The amino acids released on hydrolysis of HCN oligomers

NASA Technical Reports Server (NTRS)

Ferris, J. P.; Wos, J. D.; Nooner, D. W.; Oro, J.

1974-01-01

Major amino acids released by hydrolysis of acidic and basic HCN oligomers are identified by chromatography as Gly, Asp, and diaminosuccinic acid. Smaller amounts of Ala, Ile and alpha-aminoisobutyric acid are also detected. The amino acids released did not change appreciably when the hydrolysis medium was changed from neutral to acidic or basic. The presence of both meso and d, l-diaminosuccinic acids was established by paper chromatography and on an amino acid analyzer.

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

PubMed

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

2018-03-01

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

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.

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 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.

UNSATURATED AMINO ACIDS V.

PubMed Central

Shapira, Jacob; Dittmer, Karl

1961-01-01

Shapira, Jacob (Department of Chemistry, Florida State University, Tallahassee) and Karl Dittmer. Unsaturated amino acids. V. Microbiological properties of some halogenated olefinic amino acids. J. Bacteriol. 82:640–647. 1961.—It has been shown previously that several amino acid analogues containing unsaturated linkages were inhibitors of the growth of Escherichia coli and Saccharomyces cerevisiae. This paper reports the results obtained when a series of unsaturated halogen-containing amino acids was examined. The cis isomer of ω-chloroallylglycine showed the greatest toxicity yet found in this series of unsaturated amino acids toward E. coli, whereas the trans-isomer was usually far less toxic. The major effect of cis-ω-chloroallylglycine in E. coli appeared to be to extend the lag phase before the normal rate of growth began. A wide variety of amino acids was capable of partially or completely preventing the toxicity of low levels of these compounds. At higher levels, relatively few amino acids (primarily valine, leucine, and glutamic acid) were effective. In E. coli, cis-ω-chloroallylglycine showed an unusual [Formula: see text] relationship with both glutamic acid and valine over a wide range in concentration. PMID:13911278

Combination of amino acids reduces pigmentation in B16F0 melanoma cells.

PubMed

Ishikawa, Masago; Kawase, Ichiro; Ishii, Fumio

2007-04-01

Amino acids, the building blocks of proteins, play significant roles in numerous physiological events in mammals. As the effects of amino acids on melanogenesis have yet to be demonstrated, the present study was conducted to identify whether amino acids, in particular alanine, glycine, isoleucine and leucine, influence melanogenesis in B16F0 melanoma cells. Glycine and L-isoleucine, but not D-isoleucine, reduced melanogenesis in a concentration-dependent manner without any morphological changes in B16F0 melanoma cells. L-Alanine and L-leucine, but not D-alanine and D-leucine, also reduced melanogenesis without any morphological changes in B16F0 melanoma cells. However these amino acids did not show a concentration-dependency. Combination of L-alanine and the other amino acids, particularly 4 amino acids combination, had an additive effect on the inhibition of melanogenesis compared with single treatment of L-alanine. None of the amino acids affected the activity of tyrosinase, a key enzyme in melanogenesis. These results suggest that L-alanine, glycine, L-isoleucine and L-leucine, but not the D-form amino acids, have a hypopigmenting effect in B16F0 melanoma cells, and that these effects are not due to the inhibition of tyrosinase activity. Combination of these 4 amino acids had the additive effect on hypopigmentation that was as similar as that of kojic acid.

Two Theorems on Dissipative Energy Losses in Capacitor Systems

ERIC Educational Resources Information Center

Newburgh, Ronald

2005-01-01

This article examines energy losses in charge motion in two capacitor systems. In the first charge is transferred from a charged capacitor to an uncharged one through a resistor. In the second a battery charges an originally uncharged capacitor through a resistance. Analysis leads to two surprising general theorems. In the first case the fraction…

Concentrations of amino acids in plasma from 45- to 47-week gestation mares and foetuses (Equus caballus).

PubMed

Zicker, S C; Vivrette, S; Rogers, Q R

1994-06-01

Concentrations of 16 of 24 amino acids in plasma of foetuses were significantly higher, while four of 24 were lower, than their concentration in maternal plasma. The higher foetal concentrations of amino acids in plasma are similar to other species, with some exceptions, and suggest that equine placenta actively transports and concentrates amino acids into the umbilical circulation. Concentrations of nine of 24 amino acids were significantly lower in plasma from the umbilical artery compared to plasma from the umbilical vein, while no significant differences were present between maternal artery and vein plasma. The umbilical venous-arterial difference in concentrations of amino acids in plasma suggests the foetus extracts amino acids from the umbilical circulation for catabolism or protein synthesis, as in other species.

The simultaneous quantitation of ten amino acids in soil extracts by mass fragmentography

NASA Technical Reports Server (NTRS)

Pereira, W. E.; Hoyano, Y.; Reynolds, W. E.; Summons, R. E.; Duffield, A. M.

1972-01-01

A specific and sensitive method for the identification and simultaneous quantitation by mass fragmentography of ten of the amino acids present in soil was developed. The technique uses a computer driven quadrupole mass spectrometer and a commercial preparation of deuterated amino acids is used as internal standards for purposes of quantitation. The results obtained are comparable with those from an amino acid analyzer. In the quadrupole mass spectrometer-computer system up to 25 pre-selected ions may be monitored sequentially. This allows a maximum of 12 different amino acids (one specific ion in each of the undeuterated and deuterated amino acid spectra) to be quantitated. The method is relatively rapid (analysis time of approximately one hour) and is capable of the quantitation of nanogram quantities of amino acids.

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.

Protocol for Future Amino Acid Analyses of Samples Returned by the Stardust Mission

NASA Technical Reports Server (NTRS)

Glavin, D. P.; Doty, J. H., III; Matrajt, G.; Dworkin, J. P.

2006-01-01

We have demonstrated that LC-ToF-MS coupled with UV fluorescence detection is a powerful tool for the detection of amino acids in meteorite extracts. Using this new analytical technique we were able to identify the extraterrestrial amino acid AIB extracted from fifteen 20 micron sized Murchison meteorite grains. We found that the amino acid contamination levels in Stardust aerogels was much lower than the levels observed in the Murchison meteorite. In addition, the alpha-dialkyl amino acids AIB and isovaline which are the most abundant amino acids in Murchison were not detected in the aerogel above blank levels. We are currently integrating LIF detection capability to our existing nanoflow LC-ToF-MS for enhanced sensitivity required for the analysis of amino acids in Stardust samples.

A new family of extraterrestrial amino acids in the Murchison meteorite.

PubMed

Koga, Toshiki; Naraoka, Hiroshi

2017-04-04

The occurrence of extraterrestrial organic compounds is a key for understanding prebiotic organic synthesis in the universe. In particular, amino acids have been studied in carbonaceous meteorites for almost 50 years. Here we report ten new amino acids identified in the Murchison meteorite, including a new family of nine hydroxy amino acids. The discovery of mostly C 3 and C 4 structural isomers of hydroxy amino acids provides insight into the mechanisms of extraterrestrial synthesis of organic compounds. A complementary experiment suggests that these compounds could be produced from aldehydes and ammonia on the meteorite parent body. This study indicates that the meteoritic amino acids could be synthesized by mechanisms in addition to the Strecker reaction, which has been proposed to be the main synthetic pathway to produce amino acids.

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

PubMed

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

2017-08-01

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

Effect of experimental diabetes on the levels of aromatic and branched-chain amino acids in rat blood and brain.

PubMed

Crandall, E A; Fernstrom, J D

1983-03-01

Male rats treated 3 wk earlier with streptozotocin showed abnormally high blood levels of leucine, isoleucine, and valine throughout the 24-h period. Serum phenylalanine levels were slightly increased, while those of tryptophan and tyrosine were occasionally reduced. In brain, the level of each branched-chain amino acid was significantly increased above normal at all times. The brain concentration of each aromatic amino acid was always below normal. These changes were restored almost to normal by exogenous insulin therapy. Since the ingestion of protein is normally a major factor influencing blood amino acid levels, the effect of ingesting single, protein-containing meals on the blood and brain levels of these amino acids was also studied. After an overnight fast, the ingestion of a protein-containing meal by diabetic rats increased substantially both blood and brain levels of each branched-chain amino acid. No such increases occurred in normal rats. Ingestion of this meal produced only small changes in the brain and blood levels of the aromatic amino acids in both diabetic and normal rats. The changes in the brain level of each large neutral amino acid in some cases paralleled those in its blood level. More often, they paralleled the changes in the blood ratio of each amino acid to the sum of the other aromatic and branched-chain amino acids. This ratio is often a good predictor of the competitive transport of these amino acids into brain (Fernstrom and Faller, 1978). The observed changes in the brain levels of these amino acids in diabetes may influence the rates at which they are consumed in metabolic pathways within this organ.

Amino Acid Availability Modulates Vacuolar H+-ATPase Assembly*

PubMed Central

Stransky, Laura A.; Forgac, Michael

2015-01-01

The vacuolar H+-ATPase (V-ATPase) is an ATP-dependent proton pump composed of a peripheral ATPase domain (V1) and a membrane-integral proton-translocating domain (V0) and is involved in many normal and disease processes. An important mechanism of regulating V-ATPase activity is reversible assembly of the V1 and V0 domains. Increased assembly in mammalian cells occurs under various conditions and has been shown to involve PI3K. The V-ATPase is necessary for amino acid-induced activation of mechanistic target of rapamycin complex 1 (mTORC1), which is important in controlling cell growth in response to nutrient availability and growth signals. The V-ATPase undergoes amino acid-dependent interactions with the Ragulator complex, which is involved in recruitment of mTORC1 to the lysosomal membrane during amino acid sensing. We hypothesized that changes in the V-ATPase/Ragulator interaction might involve amino acid-dependent changes in V-ATPase assembly. To test this, we measured V-ATPase assembly by cell fractionation in HEK293T cells treated with and without amino acids. V-ATPase assembly increases upon amino acid starvation, and this effect is reversed upon readdition of amino acids. Lysosomes from amino acid-starved cells possess greater V-ATPase-dependent proton transport, indicating that assembled pumps are catalytically active. Amino acid-dependent changes in both V-ATPase assembly and activity are independent of PI3K and mTORC1 activity, indicating the involvement of signaling pathways distinct from those implicated previously in controlling assembly. By contrast, lysosomal neutralization blocks the amino acid-dependent change in assembly and reactivation of mTORC1 after amino acid starvation. These results identify an important new stimulus for controlling V-ATPase assembly. PMID:26378229

Amino acid substitutions in random mutagenesis libraries: lessons from analyzing 3000 mutations.

PubMed

Zhao, Jing; Frauenkron-Machedjou, Victorine Josiane; Kardashliev, Tsvetan; Ruff, Anna Joëlle; Zhu, Leilei; Bocola, Marco; Schwaneberg, Ulrich

2017-04-01

The quality of amino acid substitution patterns in random mutagenesis libraries is decisive for the success in directed evolution campaigns. In this manuscript, we provide a detailed analysis of the amino acid substitutions by analyzing 3000 mutations of three random mutagenesis libraries (1000 mutations each; epPCR with a low-mutation and a high-mutation frequency and SeSaM-Tv P/P) employing lipase A from Bacillus subtilis (bsla). A comparison of the obtained numbers of beneficial variants in the mentioned three random mutagenesis libraries with a site saturation mutagenesis (SSM) (covering the natural diversity at each amino acid position of BSLA) concludes the diversity analysis. Seventy-six percent of the SeSaM-Tv P/P-generated substitutions yield chemically different amino acid substitutions compared to 64% (epPCR-low) and 69% (epPCR-high). Unique substitutions from one amino acid to others are termed distinct amino acid substitutions. In the SeSaM-Tv P/P library, 35% of all theoretical distinct amino acid substitutions were found in the 1000 mutation library compared to 25% (epPCR-low) and 26% (epPCR-high). Thirty-six percent of distinct amino acid substitutions found in SeSaM-Tv P/P were unobtainable by epPCR-low. Comparison with the SSM library showed that epPCR-low covers 15%, epPCR-high 18%, and SeSaM-Tv P/P 21% of obtainable beneficial amino acid positions. In essence, this study provides first insights on the quality of epPCR and SeSaM-Tv P/P libraries in terms of amino acid substitutions, their chemical differences, and the number of obtainable beneficial amino acid positions.

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

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

PubMed

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

1998-01-01

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

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.

Stereochemistry of amino acids in surface samples of a marine sediment

NASA Technical Reports Server (NTRS)

Pollock, G. E.; Kvenvolden, K. A.

1978-01-01

In two surface samples of marine sediment, the percentages of D-alanine and D-aspartic acid are significantly higher than the other D-amino acids and are similar to the range found in soils. The percentage of D-glutamic acid is also higher than the other amino acids but less than D-alanine and D-aspartic acid. These D-amino acids may come mainly from bacteria.

Stereochemistry of amino acids in surface samples of a marine sediment

USGS Publications Warehouse

Pollock, G.E.; Kvenvolden, K.A.

1978-01-01

In two surface samples of marine sediment, the percentages of d-alanine and d-aspartic acid are significantly higher than the other d-amino acids and are similar to the range found in soils. The percentage of d-glutamic acid is also higher than the other amino acids but less than d-alanine and d-aspartic acid. These d-amino acids may come mainly from bacteria. ?? 1978.

Amino acid fermentation at the origin of the genetic code

PubMed Central

2012-01-01

There is evidence that the genetic code was established prior to the existence of proteins, when metabolism was powered by ribozymes. Also, early proto-organisms had to rely on simple anaerobic bioenergetic processes. In this work I propose that amino acid fermentation powered metabolism in the RNA world, and that this was facilitated by proto-adapters, the precursors of the tRNAs. Amino acids were used as carbon sources rather than as catalytic or structural elements. In modern bacteria, amino acid fermentation is known as the Stickland reaction. This pathway involves two amino acids: the first undergoes oxidative deamination, and the second acts as an electron acceptor through reductive deamination. This redox reaction results in two keto acids that are employed to synthesise ATP via substrate-level phosphorylation. The Stickland reaction is the basic bioenergetic pathway of some bacteria of the genus Clostridium. Two other facts support Stickland fermentation in the RNA world. First, several Stickland amino acid pairs are synthesised in abiotic amino acid synthesis. This suggests that amino acids that could be used as an energy substrate were freely available. Second, anticodons that have complementary sequences often correspond to amino acids that form Stickland pairs. The main hypothesis of this paper is that pairs of complementary proto-adapters were assigned to Stickland amino acids pairs. There are signatures of this hypothesis in the genetic code. Furthermore, it is argued that the proto-adapters formed double strands that brought amino acid pairs into proximity to facilitate their mutual redox reaction, structurally constraining the anticodon pairs that are assigned to these amino acid pairs. Significance tests which randomise the code are performed to study the extent of the variability of the energetic (ATP) yield. Random assignments can lead to a substantial yield of ATP and maintain enough variability, thus selection can act and refine the assignments 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. Reviewers: this article was reviewed by Prof. William Martin, Prof. Eörs Szathmáry (nominated by Dr. Gáspár Jékely) and Dr. Ádám Kun (nominated by Dr. Sandor Pongor) PMID:22325238

Effect of oral amino acids on counterregulatory responses and cognitive function during insulin-induced hypoglycemia in nondiabetic and type 1 diabetic people.

PubMed

Rossetti, Paolo; Porcellati, Francesca; Busciantella Ricci, Natalia; Candeloro, Paola; Cioli, Patrizia; Nair, K Sreekumaran; Santeusanio, Fausto; Bolli, Geremia B; Fanelli, Carmine G

2008-07-01

Amino acids stimulate glucagon responses to hypoglycemia and may be utilized by the brain. The aim of this study was to assess the responses to hypoglycemia in nondiabetic and type 1 diabetic subjects after ingestion of an amino acid mixture. Ten nondiabetic and 10 diabetic type 1 subjects were studied on three different occasions during intravenous insulin (2 mU . kg(-1) . min(-1)) plus variable glucose for 160 min. In two studies, clamped hypoglycemia (47 mg/dl plasma glucose for 40 min) was induced and either oral placebo or an amino acid mixture (42 g) was given at 30 min. In the third study, amino acids were given, but euglycemia was maintained. Plasma glucose and insulin were no different in the hypoglycemia studies with both placebo and amino acids (P > 0.2). After the amino acid mixture, plasma amino acid concentrations increased to levels observed after a mixed meal (2.4 +/- 0.13 vs. placebo study 1.7 +/- 0.1 mmol/l, P = 0.02). During clamped euglycemia, ingestion of amino acids resulted in transient increases in glucagon concentrations, which returned to basal by the end of the study. During clamped hypoglycemia, glucagon response was sustained and increased more in amino acid studies versus placebo in nondiabetic and diabetic subjects (P < 0.05), but other counter-regulatory hormones and total symptom score were not different. Beta-OH-butyrate was less suppressed after amino acids (200 +/- 15 vs. 93 +/- 9 micromol/l, P = 0.01). Among the cognitive tests administered, the following indicated less deterioration after amino acids than placebo: Trail-Making part B, PASAT (Paced Auditory Serial Addition Test) (2 s), digit span forward, Stroop colored words, and verbal memory tests for nondiabetic subjects; and Trail-Making part B, digit span backward, and Stroop color tests for diabetic subjects. Oral amino acids improve cognitive function in response to hypoglycemia and enhance the response of glucagon in nondiabetic and diabetic subjects.

Differences between Cryptococcus neoformans and Cryptococcus gattii in the Molecular Mechanisms Governing Utilization of D-Amino Acids as the Sole Nitrogen Source

PubMed Central

Chang, Yun C.; Khanal Lamichhane, Ami; Bradley, James; Rodgers, Laura; Ngamskulrungroj, Popchai; Kwon-Chung, Kyung J.

2015-01-01

The ability to grow on media containing certain D-amino acids as a sole nitrogen source is widely utilized to differentiate Cryptococcus gattii from C. neoformans. We used the C. neoformans H99 and C. gattii R265 strains to dissect the mechanisms of D-amino acids utilization. We identified three putative D-amino acid oxidase (DAO) genes in both strains and showed that each DAO gene plays different roles in D-amino acid utilization in each strain. Deletion of DAO2 retarded growth of R265 on eleven D-amino acids suggesting its prominent role on D-amino acid assimilation in R265. All three R265 DAO genes contributed to growth on D-Asn and D-Asp. DAO3 was required for growth and detoxification of D-Glu by both R265 and H99. Although growth of H99 on most D-amino acids was poor, deletion of DAO1 or DAO3 further exacerbated it on four D-amino acids. Overexpression of DAO2 or DAO3 enabled H99 to grow robustly on several D-amino acids suggesting that expression levels of the native DAO genes in H99 were insufficient for growth on D-amino acids. Replacing the H99 DAO2 gene with a single copy of the R265 DAO2 gene also enabled its utilization of several D-amino acids. Results of gene and promoter swaps of the DAO2 genes suggested that enzymatic activity of Dao2 in H99 might be lower compared to the R265 strain. A reduction in virulence was only observed when all DAO genes were deleted in R265 but not in H99 indicating a pathobiologically exclusive role of the DAO genes in R265. These results suggest that C. neoformans and C. gattii divergently evolved in D-amino acid utilization influenced by their major ecological niches. PMID:26132227

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.

Impact contribution of prebiotic reactants to Earth

NASA Technical Reports Server (NTRS)

Aggarwal, Hans R.

1992-01-01

It is proposed that the AIB amino acids at the K/T boundary were synthesized during entry of a comet. However, whether they were synthesized or supplied directly from space, the concentration of amino acids in the shallow K/T sea would have been about 10(exp -7) M. It is probable that clays were the dominant sinks for the amino acids in the K/T sea and in the primordial ocean. Because clay removed amino from the sea so quickly, we must study the amino acid contribution from individual comets in order to evaluate the effectiveness of comets for chemical evolution. Such an evaluation shows that comets would have produced amino acid concentrations higher than equilibrium concentrations of amino acids from corona discharge at all times preceding the age of the oldest fossils. The preferred sites for chemical evolution of cometary amino acids are in cloud drops and tide pools where the concentration of amino acids would have been the highest. Life could have originated at the surface even during periods of intense bombardment of the earth before 3.8 billion years ago.

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...

40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting under...

Almond (Prunus dulcis L.) protein quality.

PubMed

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

2005-09-01

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

Multipolar Electrostatic Energy Prediction for all 20 Natural Amino Acids Using Kriging Machine Learning.

PubMed

Fletcher, Timothy L; Popelier, Paul L A

2016-06-14

A machine learning method called kriging is applied to the set of all 20 naturally occurring amino acids. Kriging models are built that predict electrostatic multipole moments for all topological atoms in any amino acid based on molecular geometry only. These models then predict molecular electrostatic interaction energies. On the basis of 200 unseen test geometries for each amino acid, no amino acid shows a mean prediction error above 5.3 kJ mol(-1), while the lowest error observed is 2.8 kJ mol(-1). The mean error across the entire set is only 4.2 kJ mol(-1) (or 1 kcal mol(-1)). Charged systems are created by protonating or deprotonating selected amino acids, and these show no significant deviation in prediction error over their neutral counterparts. Similarly, the proposed methodology can also handle amino acids with aromatic side chains, without the need for modification. Thus, we present a generic method capable of accurately capturing multipolar polarizable electrostatics in amino acids.

Biomarkers for optimal requirements of amino acids by animals and humans.

PubMed

Lin, Gang; Liu, Chuang; Wang, Taiji; Wu, Guoyao; Qiao, Shiyan; Li, Defa; Wang, Junjun

2011-06-01

Amino acids are building blocks of proteins and key regulators of nutrient metabolism in cells. However, excessive intake of amino acids can be toxic to the body. Therefore, it is important to precisely determine amino acid requirements by organisms. To date, none of the methods is completely satisfactory to generate comprehensive data on amino acid requirements of animals or humans. Because of many influencing factors, amino acid requirements remain a complex and controversial issue in nutrition that warrants further investigations. Benefiting from the rapid advances in the emerging omics technologies and bioinformatics, biomarker discovery shows great potential in obtaining in-depth understanding of regulatory networks in protein metabolism. This review summarizes the current approaches to assess amino acid requirements of animals and humans, as well as the recent development of biomarkers as potentially functional parameters for recommending requirements of individual amino acids in health and disease. Identification of biomarkers in plasma or serum, which is a noninvasive approach, holds great promise in rapidly advancing the field of protein nutrition.

In vitro digestion and physicochemical characteristics of corn starch mixed with amino acid modified by low pressure treatment.

PubMed

Ji, Ying

2018-03-01

The digestibility and molecular structure of corn starch mixed with amino acid modified by low-pressure treatment (LPT) was investigated. Amino acid induced a significant increase in the slowly digestible starch (SDS) and decrease in the rapidly digestible starch (RDS) after LPT. The reason is the formation of ester bond between the molecular chains of amino acid and starch. Low pressure treatment altered greatly the morphology of corn starch mixed with or without amino acid. After LPT, less ordered Maltese and more granule fragments were observed for starch-amino acid complex. An increase in size distribution was obvious after LPT and the size distribution curves provided from a new variety. We found that higher enthalpy and relative crystallinity of the starch-amino acid complex were associated with a higher SDS content. It can be inferred that LPT had a greater impact on the digestion and structural characterization of corn starch mixed with amino acids. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

Characterization of vacuolar amino acid transporter from Fusarium oxysporum in Saccharomyces cerevisiae.

PubMed

Lunprom, Siriporn; Pongcharoen, Pongsanat; Sekito, Takayuki; Kawano-Kawada, Miyuki; Kakinuma, Yoshimi; Akiyama, Koichi

2015-01-01

Fusarium oxysporum causes wilt disease in many plant families, and many genes are involved in its development or growth in host plants. A recent study revealed that vacuolar amino acid transporters play an important role in spore formation in Schizosaccharomyces pombe and Saccharomyces cerevisiae. To investigate the role of vacuolar amino acid transporters of this phytopathogenic fungus, the FOXG_11334 (FoAVT3) gene from F. oxysporum was isolated and its function was characterized. Transcription of FoAVT3 was upregulated after rapamycin treatment. A green fluorescent protein fusion of FoAvt3p was localized to vacuolar membranes in both S. cerevisiae and F. oxysporum. Analysis of the amino acid content of the vacuolar fraction and amino acid transport activities using vacuolar membrane vesicles from S. cerevisiae cells heterologously expressing FoAVT3 revealed that FoAvt3p functions as a vacuolar amino acid transporter, exporting neutral amino acids. We conclude that the FoAVT3 gene encodes a vacuolar neutral amino acid transporter.

Effect of fermentation and subsequent pasteurization processes on amino acids composition of orange juice.

PubMed

Cerrillo, I; Fernández-Pachón, M S; Collado-González, J; Escudero-López, B; Berná, G; Herrero-Martín, G; Martín, F; Ferreres, F; Gil-Izquierdo, A

2015-06-01

The fermentation of fruit produces significant changes in their nutritional composition. An orange beverage has been obtained from the controlled alcoholic fermentation and thermal pasteurization of orange juice. A study was performed to determine the influence of both processes on its amino acid profile. UHPLC-QqQ-MS/MS was used for the first time for analysis of orange juice samples. Out of 29 amino acids and derivatives identified, eight (ethanolamine, ornithine, phosphoethanolamine, α-amino-n-butyric acid, hydroxyproline, methylhistidine, citrulline, and cystathionine) have not previously been detected in orange juice. The amino acid profile of the orange juice was not modified by its processing, but total amino acid content of the juice (8194 mg/L) was significantly increased at 9 days of fermentation (13,324 mg/L). Although the pasteurization process produced partial amino acid degradation, the total amino acid content was higher in the final product (9265 mg/L) than in the original juice, enhancing its nutritional value.

Selective photodestruction of alpha-amino acids. [in carbonaceous chondrites and chemical evolution experiments

NASA Technical Reports Server (NTRS)

Levi, N.; Lawless, J. G.

1978-01-01

A problem encountered in the analysis of amino acids in chemical evolution experiments and in extracts of meteorites is the large number present. A method for selectively destroying the alpha-amino acids, with only the beta- and gamma-amino acids remaining in the solution, is described. The amino acids used were racemic, with one milliliter of solution containing 0.0000025 mol of each acid irradiated in a 1-cm quartz cell having 254-nm monochromatic light in the presence of CuCl2. Excess H2S was added to precipitate the Cu (2+) as CuS. A gas chromatographic analysis was used to observe that irradiation with 254-nm light in the presence of Cu (2+) destroyed all the amino acids except the beta and the gamma types. It is concluded that with such a procedure, complex mixtures of amino acids can be simplified to make identification by GC mass spectrometry easier.

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.

Extraterrestrial Amino Acids in Orgueil and Ivuna: Tracing the Parent Body of CI Type Carbonaceous Chondrites

NASA Technical Reports Server (NTRS)

Meyer, Michael (Technical Monitor); Ehrenfreund, Pascale; Glavin, Daniel P.; Bota, Oliver; Cooper, George; Bada, Jeffrey

2001-01-01

Amino acid analyses using HPLC of pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna have found that beta-alanine, glycine, and gamma-amino-n-butyric acid (ABA) are the most abundant amino acids in these two meteorites, with concentrations ranging from approx. 600 to 2,000 parts per billion (ppb). Other alpha-amino acids such as alanine, alpha-ABA, alpha-aminoisobutyric acid (AIB), and isovaline are present only in trace amounts (less than 200 ppb). Carbon isotopic measurements of beta-alanine and glycine and the presence of racemic (D/L 1) alanine and beta-ABA in Orgueil suggest that these amino acids are extraterrestrial in origin. In comparison to the CM carbonaceous chondrites Murchison and Murray, the amino acid composition of the CIs is strikingly distinct, suggesting that these meteorites came from a different type of parent body, possibly an extinct comet, than did the CM carbonaceous chondrites.

Comparison of different amino acid derivatives and analysis of rat brain microdialysates by liquid chromatography tandem mass spectrometry.

PubMed

Uutela, Päivi; Ketola, Raimo A; Piepponen, Petteri; Kostiainen, Risto

2009-02-09

The efficiencies of three derivatisation reagents that react with either the amine (9-fluorenylmethyl chloroformate (FMOC)) or the carboxylic acid group (butanol) of amino acid or with both types of functional groups (propyl chloroformate) were compared in the analysis of amino acids by liquid chromatography-electrospray-tandem mass spectrometry (LC-ESI-MS/MS). Separation of 20 amino acids derivatised with these three reagents was studied on reversed-phase chromatography. Linearity, repeatability and limits of detection of the LC-ESI-MS/MS method were determined by analysing FMOC-, butanol- and propyl chloroformate-derivatised lysine, beta-aminobutyric acid, threonine and glutamic acid. The limits of detection for the derivatised amino acids (7.5-75fmol) were as much as 2-60 times lower than those of the corresponding underivatised molecules. The best linearity was observed for amino acids derivatised with propyl chloroformate or butanol (r(2)=0.996-0.999, range=100-8500nmolL(-1)). Propyl chloroformate was the best suited of the reagents tested for the analysis of amino acids with LC-MS/MS and was used for the analysis of amino acids in rat brain microdialysis samples.

Profiling Amino Acids of Jordanian Scalp Hair as a Tool for Diabetes Mellitus Diagnosis: A Pilot Study.

PubMed

Rashaid, Ayat H B; Harrington, Peter de B; Jackson, Glen P

2015-07-21

Hair analysis is an area of increasing interest in the fields of medical and forensic sciences. Human scalp hair has attractive features in clinical studies because hair can be sampled easily and noninvasively from human subjects, and unlike blood and urine samples, it contains a chronological record of medication use. Keratin protein is the major component of scalp hair shaft material and it is composed of 21 amino acids. The method used herein for the amino acid determination in hair included keratin protein acid hydrolysis using 6 M hydrochloric acid (HCl), followed by amino acids derivatization using N,O-bis(trimethylsilyl)trifluoroacetamide (BSTFA), and the determination of derivatized amino acids by gas chromatography/mass spectrometry (GC/MS). Amino acid profiles of scalp hair of 27 Jordanian subjects (15 diabetes mellitus (DM) type 2 patients and 12 control subjects) were analyzed. A fuzzy rule-building expert system (FuRES) classified the amino acid profiles into diabetic and control groups based on multivariate analyses of the abundance of 14 amino acids. The sensitivity and specificity were 100% for diabetes detection using leave-one-individual-out cross-validation. The areas under the receiver operative characteristics (ROC) curves were 1.0, which represents a highly sensitive and specific diabetes test. The nonessential amino acids Gly and Glu, and the essential amino acid Ile were more abundant in the scalp hair of diabetic patients compared to the hair of control subjects. The associations between the abundance of amino acids of human hair and health status may have clinical applications in providing diagnostic indicator or predicting other chronic or acute diseases.

Sensitive Amino Acid Composition and Chirality Analysis with the Mars Organic Analyzer (MOA)

NASA Technical Reports Server (NTRS)

Skelley, Alison M.; Scherer, James R.; Aubrey, Andrew D.; Grover, William H.; Ivester, Robin H. C.; Ehrenfreund, Pascale; Grunthaner, Frank J.; Bada, Jeffrey L.; Mathies, Richard A.

2005-01-01

Detection of life on Mars requires definition of a suitable biomarker and development of sensitive yet compact instrumentation capable of performing in situ analyses. Our studies are focused on amino acid analysis because amino acids are more resistant to decomposition than other biomolecules, and because amino acid chirality is a well-defined biomarker. Amino acid composition and chirality analysis has been previously demonstrated in the lab using microfabricated capillary electrophoresis (CE) chips. To analyze amino acids in the field, we have developed the Mars Organic Analyzer (MOA), a portable analysis system that consists of a compact instrument and a novel multi-layer CE microchip.

Quality control of herbs: determination of amino acids in Althaea officinalis, Matricaria chamomilla and Taraxacum officinale.

PubMed

Qureshi, Muhammad Nasimullah; Stecher, Guenther; Bonn, Guenther Karl

2014-05-01

Analysis of raw materials and final products need reliable methods for the standardization of natural product drugs. Legal guideline also emphasizes on the qualitative and quantitative analyses of the plant constituents in an herbal product. In this study, thin layer chromatography (TLC) and amino acid analyzer was used for the determination of amino acids in plant extracts. Samples for this study were standards and aqueous extracts from Althaea officinalis, Matricaria chamomilla and Taraxacum officinale. Different amino acids in the extracts were detected through TLC. An automatic amino acid analyzer was used for the quantification of amino acids in the plant extracts under study.

Effects on grape amino acid concentration through foliar application of three different elicitors.

PubMed

Gutiérrez-Gamboa, G; Portu, J; Santamaría, P; López, R; Garde-Cerdán, T

2017-09-01

Elicitors play an important role in the defense against pathogens as an alternative to chemical pesticides by increasing secondary metabolites. Their effect on grape amino acid has been little investigated. Thus, the aim of this research was to study the influence of methyl jasmonate (MeJ), chitosan (CHT), and a yeast extract (YE) on grape amino acid composition, through foliar applications to grapevines. The must amino acid concentration was analyzed by HPLC. The results showed that CHT and YE treatments decreased the must concentration of several amino acids, affecting total amino acid content (from 2364 to 1961, and 1818mg/L, respectively). However, MeJ treatment had a slight effect on grape amino acid content, increasing the concentration of Met (from 8.95 to 12.13mg/L) and Phe (from 7.96 to 9.29mg/L). It seems to be that, the resistance induction through CHT and YE treatments results in physiological costs to grapevines associated with a decrease on grape amino acid concentration. Consequently, MeJ applications, as a viticultural practice, could be a better tool than CHT and YE treatments, because did not affect grape amino acid concentration. Copyright © 2017 Elsevier Ltd. All rights reserved.

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.

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

Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories

PubMed Central

2016-01-01

The analysis of amino acids in meteorites dates back over 50 years; however, it is only in recent years that research has expanded beyond investigations of a narrow set of meteorite groups (exemplified by the Murchison meteorite) into meteorites of other types and classes. These new studies have shown a wide diversity in the abundance and distribution of amino acids across carbonaceous chondrite groups, highlighting the role of parent body processes and composition in the creation, preservation, or alteration of amino acids. Although most chiral amino acids are racemic in meteorites, the enantiomeric distribution of some amino acids, particularly of the nonprotein amino acid isovaline, has also been shown to vary both within certain meteorites and across carbonaceous meteorite groups. Large l-enantiomeric excesses of some extraterrestrial protein amino acids (up to ∼60%) have also been observed in rare cases and point to nonbiological enantiomeric enrichment processes prior to the emergence of life. In this Outlook, we review these recent meteoritic analyses, focusing on variations in abundance, structural distributions, and enantiomeric distributions of amino acids and discussing possible explanations for these observations and the potential for future work. PMID:27413780

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.

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.

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

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Naphthalenedisulfonic acid, [amino... Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo... naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy-[(methoxy-sulfophenyl)azo...

40 CFR 721.10107 - Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy...

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Naphthalenedisulfonic acid, [amino... Specific Chemical Substances § 721.10107 Naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo... naphthalenedisulfonic acid, [amino-hydroxy-[(substituted)azo-sulfo-naphthaleneyl]azo]-hydroxy-[(methoxy-sulfophenyl)azo...

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.

Crude protein and essential amino acid requirements in chicks during the first week posthatch.

PubMed

Sklan, D; Noy, Y

2003-05-01

1. This study examined optimal lysine and sulphur amino acid supply in the first week posthatch in broilers and the relationship between essential amino acids and dietary crude protein during the first week posthatch on performance at 7 d and through marketing. 2. The optimal supply during the 7 d posthatch using a 230 g/kg crude protein diet for sulphur amino acids was 9.1 and for lysine was 10.3-10.8 g/kg with maximal body weight (BW) or feed efficiency as the criteria. 3. Feeding diets with crude protein content ranging from 200 to 260 g/kg with either constant amounts of essential amino acids at different crude protein levels or constant ratios of essential amino acids to crude protein resulted in enhanced performance at 7 but not at 4 d with high protein intake and proportionally increased essential amino acids. 4. Performance on diets with crude protein ranging from 160 to 280 g/kg, with constant ratios of essential amino acid to crude protein, was much enhanced with the high crude protein diets at 7 d. All chicks were transferred to standard diets after 7 d and the BW advantage due to the balanced amino acid-high crude protein diet remained through marketing. 5. Thus increasing essential amino acids in a constant ratio to crude protein enhanced performance during the 7 d posthatch.

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.

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains

PubMed Central

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T.; Ferreira, António C.; Bauer, Florian F.

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways. PMID:29312237

The Impact of Single Amino Acids on Growth and Volatile Aroma Production by Saccharomyces cerevisiae Strains.

PubMed

Fairbairn, Samantha; McKinnon, Alexander; Musarurwa, Hannibal T; Ferreira, António C; Bauer, Florian F

2017-01-01

Nitrogen availability and utilization by Saccharomyces cerevisiae significantly influence fermentation kinetics and the production of volatile compounds important for wine aroma. Amino acids are the most important nitrogen source and have been classified based on how well they support growth. This study evaluated the effect of single amino acids on growth kinetics and major volatile production of two phenotypically different commercial wine yeast strains in synthetic grape must. Four growth parameters, lag phase, maximum growth rate, total biomass formation and time to complete fermentation were evaluated. In contrast with previous findings, in fermentative conditions, phenylalanine and valine supported growth well and asparagine supported it poorly. The four parameters showed good correlations for most amino acid treatments, with some notable exceptions. Single amino acid treatments resulted in the predictable production of aromatic compounds, with a linear correlation between amino acid concentration and the concentration of aromatic compounds that are directly derived from these amino acids. With the increased complexity of nitrogen sources, linear correlations were lost and aroma production became unpredictable. However, even in complex medium minor changes in amino acid concentration continued to directly impact the formation of aromatic compounds, suggesting that the relative concentration of individual amino acids remains a predictor of aromatic outputs, independently of the complexity of metabolic interactions between carbon and nitrogen metabolism and between amino acid degradation and utilization pathways.

Amino acid composition in parenteral nutrition: what is the evidence?

PubMed Central

Yarandi, Shadi S.; Zhao, Vivian M.; Hebbar, Gautam; Ziegler, Thomas R.

2011-01-01

Purpose of review Complete parenteral nutrition solutions contain mixed amino acid products providing all nine essential amino acids and a varying composition of nonessential amino acids. Relatively little rigorous comparative efficacy research on altered parenteral nutrition amino acid composition has been published in recent years. Recent findings Limited data from randomized, double-blind, adequately powered clinical trials to define optimal doses of total or individual amino acids in parenteral nutrition are available. An exception is the growing number of studies on the efficacy of glutamine supplementation of parenteral nutrition or given as a single parenteral agent. Parenteral glutamine appears to confer benefit in selected patients; however, additional data to define optimal glutamine dosing and the patient subgroups who may most benefit from this amino acid are needed. Although some promising studies have been published, little data are available in the current era of nutrition support on the clinical efficacy of altered doses of arginine, branched chain amino acids, cysteine, or taurine supplementation of parenteral nutrition. Summary Despite routine use of parenteral nutrition, surprisingly little clinical efficacy data are available to guide total or specific amino acid dosing in adult and pediatric patients requiring this therapy. This warrants increased attention by the research community and funding agencies to better define optimal amino acid administration strategies in patient subgroups requiring parenteral nutrition. PMID:21076291

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 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 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.

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.

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.

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

PubMed

Zicker, S C; Rogers, Q R

1994-07-01

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

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

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

Bridges, R.J.; Meister, A.

1985-06-25

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

Genetics of Amino Acid Taste and Appetite123

PubMed Central

Bosak, Natalia P; Glendinning, John I; Inoue, Masashi; Li, Xia; Manita, Satoshi; McCaughey, Stuart A; Murata, Yuko; Beauchamp, Gary K

2016-01-01

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. PMID:27422518

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.

Effects of high hydrostatic pressure on distribution dynamics of free amino acids in water soaked brown rice grain

NASA Astrophysics Data System (ADS)

Shigematsu, T.; Hayashi, M.; Nakajima, K.; Uno, Y.; Sakano, A.; Murakami, M.; Narahara, Y.; Ueno, S.; Fujii, T.

2010-03-01

High hydrostatic pressure (HP) with approximately below 400 MPa can induce a transformation of food materials to an alternative form, where membrane systems are damaged but certain enzymes are still active. HP treatment of water soaked brown rice grain could modify the mass transfer inside and apparent activities of enzymes, resulting in HP-dependent change of distribution of free amino acids. Thus, the distribution of free amino acids in brown rice grain during preservation after HP treatment was analyzed. Just after HP treatment at 200 MPa for 10 min, the distribution of free amino acids was not apparently different from that of untreated control. In contrast, after 1 to 4 days preservation at 25°C, amino acids, such as Ala, Glu, Gly, Asp and Val, showed higher concentrations than those in control. This result suggested that HP treatment induced proteolysis to produce free amino acids. However, Gln, Thr and Cys, showed no apparent difference, suggesting that conversion of certain amino acids produced by proteolysis occurred. Moreover, the concentration of γ-aminobutyric acid (GABA) in HP-treated sample was higher than that in untreated control. These results suggested that HP treatment induced alteration of distribution of free amino acids of rice grains via proteolysis and certain amino acids metabolism pathways.

Method for altering antibody light chain interactions

DOEpatents

Stevens, Fred J.; Stevens, Priscilla Wilkins; Raffen, Rosemarie; Schiffer, Marianne

2002-01-01

A method for recombinant antibody subunit dimerization including modifying at least one codon of a nucleic acid sequence to replace an amino acid occurring naturally in the antibody with a charged amino acid at a position in the interface segment of the light polypeptide variable region, the charged amino acid having a first polarity; and modifying at least one codon of the nucleic acid sequence to replace an amino acid occurring naturally in the antibody with a charged amino acid at a position in an interface segment of the heavy polypeptide variable region corresponding to a position in the light polypeptide variable region, the charged amino acid having a second polarity opposite the first polarity. Nucleic acid sequences which code for novel light chain proteins, the latter of which are used in conjunction with the inventive method, are also provided.

Library of Antifouling Surfaces Derived From Natural Amino Acids by Click Reaction.

PubMed

Xu, Chen; Hu, Xin; Wang, Jie; Zhang, Ye-Min; Liu, Xiao-Jiu; Xie, Bin-Bin; Yao, Chen; Li, Yi; Li, Xin-Song

2015-08-12

Biofouling is of great concern in numerous applications ranging from ophthalmological implants to catheters, and from bioseparation to biosensors. In this report, a general and facile strategy to combat surface fouling is developed by grafting of amino acids onto polymer substrates to form zwitterionic structure through amino groups induced epoxy ring opening click reaction. First of all, a library of poly(2-hydroxyethyl methacrylate-co-glycidyl methacrylate) hydrogels with zwitterionic surfaces were prepared, resulting in the formation of pairs of carboxyl anions and protonated secondary amino cations. The analysis of attenuated total reflectance Fourier transform infrared spectroscopy and X-ray photoelectron spectroscopy confirmed the successful immobilization of amino acids on the hydrogel surfaces. After that, the contact angle and equilibrium water content of the modified hydrogels showed that the hydrogels exhibited improved hydrophilicity compared with the parent hydrogel. Furthermore, the protein deposition was evaluated by bicinchoninic acid assay using bovine serum albumin (BSA) and lysozyme as models. The results indicated that the performance of the hydrogels was determined by the nature of incorporated amino acid: the hydrogels incorporated with neutral amino acids had nonspecific antiadsorption capability to both BSA and lysozyme; the hydrogels incorporated with charged amino acids showed antiadsorption behaviors against protein with same charge and enhanced adsorption to the protein with opposite charge; the optimal antiadsorption performance was observed on the hydrogels incorporated with polar amino acids with a hydroxyl residual. The improvement of antiprotein fouling of the neutral amino acids grafted hydrogels can be ascribed to the formation of zwitterionic surfaces. Finally, a couple of soft contact lenses grafted with amino acids were fabricated having improved antifouling property and hydrophilicity. The result demonstrated the success of amino acids based zwitterionic antifouling strategy in ophthalmology. This strategy is also applicable to substrates including filtration membranes, microspheres and nanofibers as well. It is a versatile method for amino acids grafting onto polymer substrates to construct zwitterionic surfaces and achieve antifouling properties.

40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

Code of Federal Regulations, 2011 CFR

2011-07-01

... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4... 40 Protection of Environment 31 2011-07-01 2011-07-01 false 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4â²2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl]azo]-3,3â²-dimethyl[1,1â²-biphenyl]-4-yl...

40 CFR 721.5279 - 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl...

Code of Federal Regulations, 2010 CFR

2010-07-01

... reporting. (1) The chemical substance identified as 2,7-naphthalenedisulfonic acid, 4-amino-3-[[4′2-amino-4... 40 Protection of Environment 30 2010-07-01 2010-07-01 false 2,7-Naphthalenedisulfonic acid, 4-amino-3-[[4â²2-amino-4-[(3-butoxy-2-hydroxypropyl)amino]phebyl]azo]-3,3â²-dimethyl[1,1â²-biphenyl]-4-yl...

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

Amino Acid compositions of 27 food fishes and their importance in clinical nutrition.

PubMed

Mohanty, Bimal; Mahanty, Arabinda; Ganguly, Satabdi; Sankar, T V; Chakraborty, Kajal; Rangasamy, Anandan; Paul, Baidyanath; Sarma, Debajit; Mathew, Suseela; Asha, Kurukkan Kunnath; Behera, Bijay; Aftabuddin, Md; Debnath, Dipesh; Vijayagopal, P; Sridhar, N; Akhtar, M S; Sahi, Neetu; Mitra, Tandrima; Banerjee, Sudeshna; Paria, Prasenjit; Das, Debajeet; Das, Pushpita; Vijayan, K K; Laxmanan, P T; Sharma, A P

2014-01-01

Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs.

Amino Acid Compositions of 27 Food Fishes and Their Importance in Clinical Nutrition

PubMed Central

Mahanty, Arabinda; Sankar, T. V.; Chakraborty, Kajal; Rangasamy, Anandan; Paul, Baidyanath; Sarma, Debajit; Mathew, Suseela; Asha, Kurukkan Kunnath; Behera, Bijay; Aftabuddin, Md.; Debnath, Dipesh; Vijayagopal, P.; Sridhar, N.; Akhtar, M. S.; Sahi, Neetu; Mitra, Tandrima; Banerjee, Sudeshna; Das, Debajeet; Das, Pushpita; Vijayan, K. K.; Laxmanan, P. T.; Sharma, A. P.

2014-01-01

Proteins and amino acids are important biomolecules which regulate key metabolic pathways and serve as precursors for synthesis of biologically important substances; moreover, amino acids are building blocks of proteins. Fish is an important dietary source of quality animal proteins and amino acids and play important role in human nutrition. In the present investigation, crude protein content and amino acid compositions of important food fishes from different habitats have been studied. Crude protein content was determined by Kjeldahl method and amino acid composition was analyzed by high performance liquid chromatography and information on 27 food fishes was generated. The analysis showed that the cold water species are rich in lysine and aspartic acid, marine fishes in leucine, small indigenous fishes in histidine, and the carps and catfishes in glutamic acid and glycine. The enriched nutrition knowledge base would enhance the utility of fish as a source of quality animal proteins and amino acids and aid in their inclusion in dietary counseling and patient guidance for specific nutritional needs. PMID:25379285

Simultaneous determination of free amino acids in Pu-erh tea and their changes during fermentation.

PubMed

Zhu, Yuchen; Luo, Yinghua; Wang, Pengpu; Zhao, Mengyao; Li, Lei; Hu, Xiaosong; Chen, Fang

2016-03-01

Pu-erh ripened tea is produced through a unique microbial fermentation process from the sun-dried leaves of large-leaf tea species (Camellia sinensis (Linn.) var. assamica (Masters) Kitamura) in Yunnan province of China. In this study, the changes of amino acid profiles during fermentation of Pu-erh tea were investigated, based on the improved HPLC-UV method with PITC pre-column derivatization for the simultaneous determination of twenty free amino acids. Results showed that aspartic acid, glutamic acid, arginine, alanine, theanine and tyrosine were the major amino acids in tea samples. Fermentation significantly influenced on the amino acid profiles. The total free amino acid contents significantly decreased during fermentation (p<0.05). Meanwhile, low amount of acrylamide were detected. Its concentration increased after 7-days' fermentation and then decreased gradually. The results provided the useful information for the manipulation of fermentation process according to the changes of amino acids and acrylamide contents in Pu-erh ripened tea. Copyright © 2015 Elsevier Ltd. All rights reserved.

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.

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

PubMed

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

2002-09-01

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

Amino acidis derived from Titan tholins

NASA Technical Reports Server (NTRS)

Khare, Bishun N.; Sagan, Carl; Ogino, Hiroshi; Nagy, Bartholomew; Er, Cevat

1986-01-01

The production of amino acids by acid treatment of Titan tholin is experimentally investigated. The synthesis of Titan tholin and the derivatization of amino acids to N-trifluoroacetyl isopropyl esters are described. The gas chromatography/mass spectroscopy analysis of the Titan tholins reveals the presence of glycine, alpha and beta alainine, and aspartic acid, and the total yield of amino acids is about 0.01.

Effect of a new injectable male contraceptive on the seminal plasma amino acids studied by proton NMR spectroscopy.

PubMed

Chaudhury, Koel; Sharma, Uma; Jagannathan, N R; Guha, Sujoy K

2002-09-01

Effect of RISUG, a newly developed male contraceptive, on various amino acids of seminal plasma ejaculates was studied by proton magnetic resonance spectroscopy at 400 MHz. Levels of amino acids were compared with the seminal plasma of obstructive azoospermia and controls. Glutamic acid, glutamine, and arginine were found to be high in concentration in human seminal plasma. The concentration of aromatic amino acids such as tyrosine, histidine, and phenylalanine in RISUG-injected subjects showed no significant difference compared to controls (p > 0.1); however, there was a statistically significant decrease in the concentration of these amino acids in obstructive azoospermia. The concentration of some prominent amino acids that showed overlapping resonances, such as isoleucine+leucine+valine (p < 0.01), alanine+isoleucine+lysine (p < 0.01), arginine+lysine+leucine (p < 0.01), and glutamic acid+glutamine (p < 0.01), showed a statistically significant decrease in RISUG-injected subjects compared to controls. Overlap of these amino acid resonances were noticed even at 600 MHz. In general, the total amino acids concentration in RISUG-injected subjects was found to be higher than in azoospermic subjects, confirming the occurrence of 'partial' obstructive azoospermia in subjects injected with this contraceptive.

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

Synthesis of an Uncharged Tetra-cyclopeptide Acting as a Transmembrane Carrier: Enhanced Cellular and Nuclear Uptake.

PubMed

Francisco Hilário, Flaviane; Traoré, Mohamed Dit Mady; Zwick, Vincent; Berry, Laurence; Simões-Pires, Claudia A; Cuendet, Muriel; Fantozzi, Nicolas; Pereira de Freitas, Rossimiriam; Maynadier, Marjorie; Wein, Sharon; Vial, Henri; Wong, Yung-Sing

2017-02-03

A small uncharged cyclopeptide scaffold inspired by a natural product and designed to undergo postfunctionalizations was used as a new transmembrane vector. A bioactive and fluorescent triazole aminocoumarin was bound to this carrier to facilitate its moving across cell and subcellular membranes, and this led to an increase in its cell toxicity.

DNA polymerase ι: The long and the short of it!

PubMed

Frank, Ekaterina G; McLenigan, Mary P; McDonald, John P; Huston, Donald; Mead, Samantha; Woodgate, Roger

2017-10-01

The cDNA encoding human DNA polymerase ι (POLI) was cloned in 1999. At that time, it was believed that the POLI gene encoded a protein of 715 amino acids. Advances in DNA sequencing technologies led to the realization that there is an upstream, in-frame initiation codon that would encode a DNA polymerase ι (polι) protein of 740 amino acids. The extra 25 amino acid region is rich in acidic residues (11/25) and is reasonably conserved in eukaryotes ranging from fish to humans. As a consequence, the curated Reference Sequence (RefSeq) database identified polι as a 740 amino acid protein. However, the existence of the 740 amino acid polι has never been shown experimentally. Using highly specific antibodies to the 25 N-terminal amino acids of polι, we were unable to detect the longer 740 amino acid (ι-long) isoform in western blots. However, trace amounts of the ι-long isoform were detected after enrichment by immunoprecipitation. One might argue that the longer isoform may have a distinct biological function, if it exhibits significant differences in its enzymatic properties from the shorter, well-characterized 715 amino acid polι. We therefore purified and characterized recombinant full-length (740 amino acid) polι-long and compared it to full-length (715 amino acid) polι-short in vitro. The metal ion requirements for optimal catalytic activity differ slightly between ι-long and ι-short, but under optimal conditions, both isoforms exhibit indistinguishable enzymatic properties in vitro. We also report that like ι-short, the ι-long isoform can be monoubiquitinated and polyubiuquitinated in vivo, as well as form damage induced foci in vivo. We conclude that the predominant isoform of DNA polι in human cells is the shorter 715 amino acid protein and that if, or when, expressed, the longer 740 amino acid isoform has identical properties to the considerably more abundant shorter isoform. Published by Elsevier B.V.

Production of carrier-peptide conjugates using chemically reactive unnatural amino acids

DOEpatents

Young, Travis; Schultz, Peter G

2013-12-17

Provided are methods of making carrier polypeptide that include incorporating a first unnatural amino acid into a carrier polypeptide variant, incorporating a second unnatural amino acid into a target polypeptide variant, and reacting the first and second unnatural amino acids to produce the conjugate. Conjugates produced using the provided methods are also provided. In addition, orthogonal translation systems in methylotrophic yeast and methods of using these systems to produce carrier and target polypeptide variants comprising unnatural amino acids are provided.

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.

Production of carrier-peptide conjugates using chemically reactive unnatural amino acids

DOEpatents

Young, Travis; Schultz, Peter G

2014-01-28

Provided are methods of making carrier polypeptide that include incorporating a first unnatural amino acid into a carrier polypeptide variant, incorporating a second unnatural amino acid into a target polypeptide variant, and reacting the first and second unnatural amino acids to produce the conjugate. Conjugates produced using the provided methods are also provided. In addition, orthogonal translation systems in methylotrophic yeast and methods of using these systems to produce carrier and target polypeptide variants comprising unnatural amino acids are provided.

Production of carrier-peptide conjugates using chemically reactive unnatural amino acids

DOEpatents

Young, Travis; Schultz, Peter G.

2015-08-18

Provided are methods of making carrier polypeptide that include incorporating a first unnatural amino acid into a carrier polypeptide variant, incorporating a second unnatural amino acid into a target polypeptide variant, and reacting the first and second unnatural amino acids to produce the conjugate. Conjugates produced using the provided methods are also provided. In addition, orthogonal translation systems in methylotrophic yeast and methods of using these systems to produce carrier and target polypeptide variants comprising unnatural amino acids are provided.

Chiral separation of norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, and three benzoin derivatives using amino acid based molecular micelles.

PubMed

Billiot, Fereshteh H; Billiot, Eugene J; Ng, Yuen Kwun; Warner, Isiah M

2006-02-01

In this study, 18 polymeric single amino acid and dipeptide surfactants are examined, and their performances, in terms of enantioselectivity, are compared for norlaudanosoline, laudanosoline, laudanosine, chlorthalidone, benzoin, benzoin methyl, and benzoin ethyl enantiomers. Several aspects of amino acid-based polymeric surfactants including comparison of single amino acid versus dipeptide, amino acid order, steric effect, and effect of the position of the chiral center of dipeptide surfactants on the chiral selectivity of these optically active compounds are discussed.

Concentrations and nitrogen isotope compositions of free amino acids in Pinus massoniana (Lamb.) needles of different ages as indicators of atmospheric nitrogen pollution

NASA Astrophysics Data System (ADS)

Xu, Yu; Xiao, Huayun

2017-09-01

Free amino acid δ15N values and concentrations of current-year new (new), current-year mature (middle-age) and previous-year (old) Pinus massoniana (Lamb.) needles were determined for five sites with different distances from a highway in a forest in Guiyang (SW China). Needle free amino acid concentrations decreased with increasing distance from the highway, and only the free amino acid concentrations (total free amino acid, arginine, γ-aminobutyric acid, valine, alanine and proline) in the middle-aged needles demonstrated a strong correlation with distance from the highway, indicating that free amino acid concentrations in middle-aged needles may be a more suitable indicator of nitrogen (N) deposition compared to new and old needles. Needle free amino acid δ15N values were more positive near the highway compared to the more distant sites and increased with increasing needle age, indicating that N deposition in this site may be dominated by isotopically heavy NOx-N from traffic emissions. In sites beyond 400 m from the highway, the δ15N values of total free amino acids, histidine, glutamine, proline, alanine, aspartate, isoleucine, lysine, arginine and serine in each age of needle were noticeably negative compared to their respective δ15N values near the highway. This suggested that needle free amino acid δ15N values from these sites were more affected by 15N-depleted atmospheric NHx-N from soil emissions. This result was further supported by the similarity in the negative moss δ15N values at these sites to the δ15N values of soil-derived NHx-N. Needle free amino acid δ15N values therefore have the potential to provide information about atmospheric N sources. We conclude that needle free amino acid concentrations are sensitive indicators of N deposition and that the age-related free amino acid δ15N values in needles can efficiently reflect atmospheric N sources. This would probably promote the application of the combined plant tissue amino acid concentration and δ15N analyses in N deposition bio-monitoring.

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.

Racemization in Reverse: Evidence that D-Amino Acid Toxicity on Earth Is Controlled by Bacteria with Racemases

PubMed Central

Zhang, Gaosen; Sun, Henry J.

2014-01-01

D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free. PMID:24647559

Racemization in reverse: evidence that D-amino acid toxicity on Earth is controlled by bacteria with racemases.

PubMed

Zhang, Gaosen; Sun, Henry J

2014-01-01

D-amino acids are toxic for life on Earth. Yet, they form constantly due to geochemical racemization and bacterial growth (the cell walls of which contain D-amino acids), raising the fundamental question of how they ultimately are recycled. This study provides evidence that bacteria use D-amino acids as a source of nitrogen by running enzymatic racemization in reverse. Consequently, when soils are inundated with racemic amino acids, resident bacteria consume D- as well as L-enantiomers, either simultaneously or sequentially depending on the level of their racemase activity. Bacteria thus protect life on Earth by keeping environments D-amino acid free.

Synthesis of novel lipoamino acid conjugates of sapienic acid and evaluation of their cytotoxicity activities.

PubMed

Gopal, Sanganamoni Chinna; Kaki, Shiva Shanker; Rao, Bhamidipati V S K; Poornachandra, Yedla; Kumar, Chityal Ganesh; Narayana Prasad, Rachapudi Badari

2014-01-01

Novel lipoamino acids were prepared with the coupling of sapienic acid [(Z)-6-hexadecenoic acid] with α - amino group of amino acids and the resulting N-sapienoyl amino acids were tested for their cytotoxicity activities against four cancer based cell lines. Initially, sapienic acid was synthesized by the Wittig coupling of triphenylphosphonium bromide salt of 6-bromohexanoic acid and decanal with a Z specific reagent. The prepared sapienic acid was subsequently converted to its acid chloride which was further coupled with amino acids by the Schotten-Baumann reaction to form N-sapienoyl amino acid conjugates. Structural characterization of the prepared N-sapienoyl amino acid derivatives was done by spectral data (IR, mass spectra and NMR). These lipoamino acid derivatives were screened for in vitro cytotoxicity evaluation. Cytotoxicity evaluation against four cancer cell lines showed that N-sapienoyl isoleucine was active against three cell lines whereas other derivatives either showed activity against only one or two cell lines with very moderate activity and two derivatives were observed to be inactive against the tested cell lines.

Quest for steroidomimetics: Amino acids derived steroidal and nonsteroidal architectures.

PubMed

Shagufta; Ahmad, Irshad; Panda, Gautam

2017-06-16

The chiral pool amino acids have been utilized for the construction of steroidal and non-steroidal architectures in the quest for steroidomimetics. Chirality derived from amino acid-based architectures provides new and easy to incorporate chiral chemical space, which is otherwise very difficult to introduce and comprised of several synthetic steps for asymmetric steroids. The different and exciting ligand-receptor interactions may arise from the use of each amino acid enantiomer that was introduced into the chiral steroidal backbone. The A and D rings of steroidal architectures can be mimicked by the phenyl group of the amino acid tyrosine. The Mitsunobu reaction, nucleophilic substitution and elimination, etc. were utilized for constructing diverse tri- and tetracyclic steroidal skeletons as well as benzofused seco-steroids from amino acids. These benzofused, amino acid-derived steroidal and nonsteroidal molecules had promising biological activity in hormonal related disorders. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Surface Propensity of Atmospherically Relevant Amino Acids Studied by XPS.

PubMed

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

2017-04-27

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

Geochemistry of amino acids in shells of the clam Saxidomus

USGS Publications Warehouse

Kvenvolden, K.A.; Blunt, D.J.; McMenamin, M.A.; Straham, S.E.

1980-01-01

Concentrations of amino acids and their corresponding d l enantiomeric ratios have been measured in shells of the bivalve mollusk Saxidomus from eleven localities, ranging in age from modern to probably more than 500,000 yr, along the Pacific coast of North America. Natural logarithms of amino acid concentrations correlate well with d l ratios, and the relationship provides a possible guide to the selection of fossils for use in amino acid dating. The relative order of the extents of racemization of amino acids at any given time appears to change with increasing sample age. Application of the amino acid dating method to shells from Whidbey Island, Washington, yields an age of about 80,000 yr, in contrast to the previously determined radiocarbon age of 36,000 yr which was measured on some shell carbonate and considered a minimum age. The amino acid age is compatible with the geologic record in the area. ?? 1980.

High-level production of C-11-carboxyl-labeled amino acids. [For use in tumor and pancreatic imaging

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

Washburn, L. C.; Sun, T. T.; Byrd, B. L.

Carbon-11-labeled amino acids have significant potential as agents for positron tomographic functional imaging. We have developed a rapid, high-temperature, high-pressure modification of the Buecherer--Strecker amino acid synthesis and found it to be quite general for the production of C-11-carboxyl-labeled neutral amino acids. Production of C-11-carboxyl-labeled DL-tryptophan requires certain modifications in the procedure. Twelve different amino acids have been produced to date by this technique. Synthesis and chromatographic purification require approximately 40 min, and C-11-carboxyl-labeled amino acids have been produced in yields of up to 425 mCi. Two C-11-carboxyl-labeled amino acids are being investigated clinically for tumor scanning and two othersmore » for pancreatic imaging. Over 120 batches of the various agents have been produced for clinical use over a three-year period.« less

Modulatory Effects of Dietary Amino Acids on Neurodegenerative Diseases.

PubMed

Rajagopal, Senthilkumar; Sangam, Supraj Raja; Singh, Shubham; Joginapally, Venkateswara Rao

2016-01-01

Proteins are playing a vital role in maintaining the cellular integrity and function, as well as for brain cells. Protein intake and supplementation of individual amino acids can affect the brain functioning and mental health, and many of the neurotransmitters in the brain are made from amino acids. The amino acid supplementation has been found to reduce symptoms, as they are converted into neurotransmitters which in turn extenuate the mental disorders. The biosynthesis of amino acids in the brain is regulated by the concentration of amino acids in plasma. The brain diseases such as depression, bipolar disorder, schizophrenia, obsessive-compulsive disorder (OCD), and Alzheimer's (AD), Parkinson's (PD), and Huntington's diseases (HD) are the most common mental disorders that are currently widespread in numerous countries. The intricate biochemical and molecular machinery contributing to the neurological disorders is still unknown, and in this chapter, we revealed the involvement of dietary amino acids on neurological diseases.

Distribution and Origin of Amino Acids in Lunar Regolith Samples

NASA Technical Reports Server (NTRS)

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

2015-01-01

The existence of organic compounds on the lunar surface has been a question of interest from the Apollo era to the present. Investigations of amino acids immediately after collection of lunar samples yielded inconclusive identifications, in part due to analytical limitations including insensitivity to certain compounds, an inability to separate enantiomers, and lack of compound-specific isotopic measurements. It was not possible to determine if the detected amino acids were indigenous to the lunar samples or the result of terrestrial contamination. Recently, we presented initial data from the analysis of amino acid abundances in 12 lunar regolith samples and discussed those results in the context of four potential amino acid sources [5]. Here, we expand on our previous work, focusing on amino acid abundances and distributions in seven regolith samples and presenting the first compound-specific carbon isotopic ratios measured for amino acids in a lunar sample.

Asparagine promotes cancer cell proliferation through use as an amino acid exchange factor

PubMed Central

Krall, Abigail S.; Xu, Shili; Graeber, Thomas G.; Braas, Daniel; Christofk, Heather R.

2016-01-01

Cellular amino acid uptake is critical for mTOR complex 1 (mTORC1) activation and cell proliferation. However, the regulation of amino acid uptake is not well-understood. Here we describe a role for asparagine as an amino acid exchange factor: intracellular asparagine exchanges with extracellular amino acids. Through asparagine synthetase knockdown and altering of media asparagine concentrations, we show that intracellular asparagine levels regulate uptake of amino acids, especially serine, arginine and histidine. Through its exchange factor role, asparagine regulates mTORC1 activity and protein synthesis. In addition, we show that asparagine regulation of serine uptake influences serine metabolism and nucleotide synthesis, suggesting that asparagine is involved in coordinating protein and nucleotide synthesis. Finally, we show that maintenance of intracellular asparagine levels is critical for cancer cell growth. Collectively, our results indicate that asparagine is an important regulator of cancer cell amino acid homeostasis, anabolic metabolism and proliferation. PMID:27126896

Carbon-11 and Fluorine-18 Labeled Amino Acid Tracers for Positron Emission Tomography Imaging of Tumors

NASA Astrophysics Data System (ADS)

Sun, Aixia; Liu, Xiang; Tang, Ganghua

2017-12-01

Tumor cells have an increased nutritional demand for amino acids(AAs) to satisfy their rapid proliferation. Positron-emitting nuclide labeled AAs are interesting probes and are of great importance for imaging tumors using positron emission tomography (PET). Carbon-11 and fluorine-18 labeled AAs include the [1-11C] amino acids, labeling alpha-C- amino acids, the branched-chain of amino acids and N-substituted carbon-11 labeled amino acids. These tracers target protein synthesis or amino acid(AA) transport, and their uptake mechanism mainly involves AA transport. AA PET tracers have been widely used in clinical settings to image brain tumors, neuroendocrine tumors, prostate cancer, breast cancer, non–small cell lung cancer (NSCLC) and hepatocellular carcinoma. This review focuses on the fundamental concepts and the uptake mechanism of AAs, AA PET tracers and their clinical applications.

40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting under...

40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting under...

40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

37 CFR 1.821 - Nucleotide and/or amino acid sequence disclosures in patent applications.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 37 Patents, Trademarks, and Copyrights 1 2010-07-01 2010-07-01 false Nucleotide and/or amino acid... Biotechnology Invention Disclosures Application Disclosures Containing Nucleotide And/or Amino Acid Sequences § 1.821 Nucleotide and/or amino acid sequence disclosures in patent applications. (a) Nucleotide and...

37 CFR 5.31-5.33 - [Reserved

Code of Federal Regulations, 2011 CFR

2011-07-01

... from abandonment 1.135 Amino Acid Sequences. (See Nucleotide and/or Amino Acid Sequences) Appeal to... Appeals and Interference 41.47 Of rejection of an application 1.104(a) Nucleotide and/or Amino Acid...) Symbols for nucleotide and/or amino acid sequence data 1.822 T Tables in patent applications 1.58 Terminal...

40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No. 693...

37 CFR 1.821 - Nucleotide and/or amino acid sequence disclosures in patent applications.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 37 Patents, Trademarks, and Copyrights 1 2011-07-01 2011-07-01 false Nucleotide and/or amino acid... Biotechnology Invention Disclosures Application Disclosures Containing Nucleotide And/or Amino Acid Sequences § 1.821 Nucleotide and/or amino acid sequence disclosures in patent applications. (a) Nucleotide and...

40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting under...

40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting under...

40 CFR 721.430 - Oxo-substituted amino-al-kanoic acid derivative.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Oxo-substituted amino-al-kanoic acid... Specific Chemical Substances § 721.430 Oxo-substituted amino-al-kanoic acid derivative. (a) Chemical... as oxo-substituted amino al-kan-oic acid derivative (PMN No. P-92-692) is subject to reporting under...

Amino acid analysis in physiological samples by GC-MS with propyl chloroformate derivatization and iTRAQ-LC-MS/MS.

PubMed

Dettmer, Katja; Stevens, Axel P; Fagerer, Stephan R; Kaspar, Hannelore; Oefner, Peter J

2012-01-01

Two mass spectrometry-based methods for the quantitative analysis of free amino acids are described. The first method uses propyl chloroformate/propanol derivatization and gas chromatography-quadrupole mass spectrometry (GC-qMS) analysis in single-ion monitoring mode. Derivatization is carried out directly in aqueous samples, thereby allowing automation of the entire procedure, including addition of reagents, extraction, and injection into the GC-MS. The method delivers the quantification of 26 amino acids. The isobaric tagging for relative and absolute quantification (iTRAQ) method employs the labeling of amino acids with isobaric iTRAQ tags. The tags contain two different cleavable reporter ions, one for the sample and one for the standard, which are detected by fragmentation in a tandem mass spectrometer. Reversed-phase liquid chromatography of the labeled amino acids is performed prior to mass spectrometric analysis to separate isobaric amino acids. The commercial iTRAQ kit allows for the analysis of 42 physiological amino acids with a respective isotope-labeled standard for each of these 42 amino acids.

Alignment-based and alignment-free methods converge with experimental data on amino acids coded by stop codons at split between nuclear and mitochondrial genetic codes.

PubMed

Seligmann, Hervé

2018-05-01

Genetic codes mainly evolve by reassigning punctuation codons, starts and stops. Previous analyses assuming that undefined amino acids translate stops showed greater divergence between nuclear and mitochondrial genetic codes. Here, three independent methods converge on which amino acids translated stops at split between nuclear and mitochondrial genetic codes: (a) alignment-free genetic code comparisons inserting different amino acids at stops; (b) alignment-based blast analyses of hypothetical peptides translated from non-coding mitochondrial sequences, inserting different amino acids at stops; (c) biases in amino acid insertions at stops in proteomic data. Hence short-term protein evolution models reconstruct long-term genetic code evolution. Mitochondria reassign stops to amino acids otherwise inserted at stops by codon-anticodon mismatches (near-cognate tRNAs). Hence dual function (translation termination and translation by codon-anticodon mismatch) precedes mitochondrial reassignments of stops to amino acids. Stop ambiguity increases coded information, compensates endocellular mitogenome reduction. Mitochondrial codon reassignments might prevent viral infections. Copyright © 2018 Elsevier B.V. All rights reserved.

Vacuolar transporter Avt4 is involved in excretion of basic amino acids from the vacuoles of Saccharomyces cerevisiae.

PubMed

Sekito, Takayuki; Chardwiriyapreecha, Soracom; Sugimoto, Naoko; Ishimoto, Masaya; Kawano-Kawada, Miyuki; Kakinuma, Yoshimi

2014-01-01

Basic amino acids (lysine, histidine and arginine) accumulated in Saccharomyces cerevisiae vacuoles should be mobilized to cytosolic nitrogen metabolism under starvation. We found that the decrease of vacuolar basic amino acids in response to nitrogen starvation was impaired by the deletion of AVT4 gene encoding a vacuolar transporter. In addition, overexpression of AVT4 reduced the accumulation of basic amino acids in vacuoles under nutrient-rich condition. In contrast to AVT4, the deletion and overexpression of AVT3, which encodes the closest homologue of Avt4p, did not affect the contents of vacuolar basic amino acids. Consistent with these, arginine uptake into vacuolar membrane vesicles was decreased by Avt4p-, but not by Avt3p-overproduction, whereas various neutral amino acids were excreted from vacuolar membrane vesicles in a manner dependent on either Avt4p or Avt3p. These results suggest that Avt4p is a vacuolar amino acid exporter involving in the recycling of basic amino acids.

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.

Plasma amino acid concentrations in 36 dogs with histologically confirmed superficial necrolytic dermatitis.

PubMed

Outerbridge, Catherine A; Marks, Stanley L; Rogers, Quinton R

2002-08-01

Plasma amino acid concentrations were measured in 36 dogs diagnosed with superficial necrolytic dermatitis (SND) via skin biopsy. The median age of the dogs was 10 years, and 27 out of 36 (75%) were male. Twenty-two out of 36 (61%) of the dogs were accounted for by six breeds; West Highland white terriers (six), Shetland sheepdogs (five), cocker spaniels (four), Scottish terriers (three), Lhasa apsos (two) and Border collies (two). The mean concentration (+/- standard deviation) was calculated for each measured plasma amino acid and compared to previously documented concentrations of plasma amino acids measured in dogs with acute and chronic hepatitis. The ratio of branched chain amino acids to aromatic amino acids in the dogs with SND was 2.6, slightly lower than that in normal dogs. The mean plasma amino acid concentrations for dogs with SND were significantly lower than for dogs with acute and chronic hepatitis. A metabolic hepatopathy in which there is increased hepatic catabolism of amino acids is hypothesized to explain the hypoaminoacidaemia seen in SND.

Development of a liquid chromatography-tandem mass spectrometry method for quantitative analysis of trace d-amino acids.

PubMed

Nakano, Yosuke; Konya, Yutaka; Taniguchi, Moyu; Fukusaki, Eiichiro

2017-01-01

d-Amino acids have recently attracted much attention in various research fields including medical, clinical and food industry due to their important biological functions that differ from l-amino acid. Most chiral amino acid separation techniques require complicated derivatization procedures in order to achieve the desirable chromatographic behavior and detectability. Thus, the aim of this research is to develop a highly sensitive analytical method for the enantioseparation of chiral amino acids without any derivatization process using liquid chromatography-tandem mass spectrometry (LC-MS/MS). By optimizing MS/MS parameters, we established a quantification method that allowed the simultaneous analysis of 18 d-amino acids with high sensitivity and reproducibility. Additionally, we applied the method to food sample (vinegar) for the validation, and successfully quantified trace levels of d-amino acids in samples. These results demonstrated the applicability and feasibility of the LC-MS/MS method as a novel, effective tool for d-amino acid measurement in various biological samples. Copyright © 2016 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Bias-Exchange Metadynamics Simulation of Membrane Permeation of 20 Amino Acids.

PubMed

Cao, Zanxia; Bian, Yunqiang; Hu, Guodong; Zhao, Liling; Kong, Zhenzhen; Yang, Yuedong; Wang, Jihua; Zhou, Yaoqi

2018-03-16

Thermodynamics of the permeation of amino acids from water to lipid bilayers is an important first step for understanding the mechanism of cell-permeating peptides and the thermodynamics of membrane protein structure and stability. In this work, we employed bias-exchange metadynamics simulations to simulate the membrane permeation of all 20 amino acids from water to the center of a dipalmitoylphosphatidylcholine (DPPC) membrane (consists of 256 lipids) by using both directional and torsion angles for conformational sampling. The overall accuracy for the free energy profiles obtained is supported by significant correlation coefficients (correlation coefficient at 0.5-0.6) between our results and previous experimental or computational studies. The free energy profiles indicated that (1) polar amino acids have larger free energy barriers than nonpolar amino acids; (2) negatively charged amino acids are the most difficult to enter into the membrane; and (3) conformational transitions for many amino acids during membrane crossing is the key for reduced free energy barriers. These results represent the first set of simulated free energy profiles of membrane crossing for all 20 amino acids.

Cyanobacteria as efficient producers of mycosporine-like amino acids.

PubMed

Jain, Shikha; Prajapat, Ganshyam; Abrar, Mustari; Ledwani, Lalita; Singh, Anoop; Agrawal, Akhil

2017-09-01

Mycosporine-like amino acids are the most common group of transparent ultraviolet radiation absorbing intracellular secondary metabolites. These molecules absorb light in the range of ultraviolet-A and -B with a maximum absorbance between 310 and 362 nm. Cyanobacteria might have faced the most deleterious ultraviolet radiation, which leads to an evolution of ultraviolet protecting mycosporine-like amino acids for efficient selection in the environment. In the last 30 years, scientists have investigated various cyanobacteria for novel mycosporine-like amino acids, applying different induction techniques. This review organizes all the cyanobacterial groups that produce various mycosporine-like amino acids. We found out that cyanobacteria belonging to orders Synechococcales, Chroococcales, Oscillatoriales, and Nostocales are frequently studied for the presence of mycosporine-like amino acids, while orders Gloeobacterales, Spirulinales, Pleurocapsales, and Chroococcidiopsidales are still need to be investigated. Nostoc and Anabaena strains are major studied genus for the mycosporine-like amino acids production. Hence, this review will give further insight to the readers about potential mycosporine-like amino acid producing cyanobacterial groups in future investigations. © 2017 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

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

Formation of specific amino acid sequences during carbodiimide-mediated condensation of amino acids in aqueous solution, and computer-simulated sequence generation

NASA Astrophysics Data System (ADS)

Hartmann, Jürgen; Nawroth, Thomas; Dose, Klaus

1984-12-01

Carbodiimide-mediated peptide synthesis in aqueous solution has been studied with respect to self-ordering of amino acids. The copolymerisation of amino acids in the presence of glutamic acid or pyroglutamic acid leads to short pyroglutamyl peptides. Without pyroglutamic acid the formation of higher polymers is favoured. The interactions of the amino acids and the peptides, however, are very complex. Therefore, the experimental results are rather difficult to explain. Some of the experimental results, however, can be explained with the aid of computer simulation programs. Regarding only the tripeptide fraction the copolymerisation of pyroGlu, Ala and Leu, as well as the simulated copolymerisation lead to pyroGlu-Ala-Leu as the main reaction product. The amino acid composition of the insoluble peptides formed during the copolymerisation of Ser, Gly, Ala, Val, Phe, Leu and Ile corresponds in part to the computer-simulated copolymerisation data.

Accumulated analyses of amino acid precursors in returned lunar samples

NASA Technical Reports Server (NTRS)

Fox, S. W.; Harada, K.; Hare, P. E.

1973-01-01

Six amino acids (glycine, alanine, aspartic acid, glutamic acid, serine, and threonine) obtained by hydrolysis of extracts have been quantitatively determined in ten collections of fines from five Apollo missions. Although the amounts found, 7-45 ng/g, are small, the lunar amino acid/carbon ratios are comparable to those of the carbonaceous chondrites, Murchison and Murray, as analyzed by the same procedures. Since both the ratios of amino acid to carbon, and the four or five most common types of proteinous amino acid found, are comparable for the two extraterrestrial sources despite different cosmophysical histories of the moon and meteorites, common cosmochemical processes are suggested.

Delivery of extraterrestrial amino acids to the primitive Earth. Exposure experiments in Earth orbit.

PubMed

Barbier, B; Bertrand, M; Boillot, F; Chabin, A; Chaput, D; Henin, O; Brack, A

1998-06-01

A large collection of micrometeorites has been recently extracted from Antarctic old blue ice. In the 50 to 100 micrometers size range, the carbonaceous micrometeorites represent 80% of the samples and contain 2% of carbon. They might have brought more carbon to the surface of the primitive Earth than that involved in the present surficial biomass. Amino acids such as "-amino isobutyric acid have been identified in these Antarctic micrometeorites. Enantiomeric excesses of L-amino acids have been detected in the Murchison meteorite. A large fraction of homochiral amino acids might have been delivered to the primitive Earth via meteorites and micrometeorites. Space technology in Earth orbit offers a unique opportunity to study the behaviour of amino acids required for the development of primitive life when they are exposed to space conditions, either free or associated with tiny mineral grains mimicking the micrometeorites. Our objectives are to demonstrate that porous mineral material protects amino acids in space from photolysis and racemization (the conversion of L-amino acids into a mixture of L- and D-molecules) and to test whether photosensitive amino acids derivatives can polymerize in mineral grains under space conditions. The results obtained in BIOPAN-1 and BIOPAN-2 exposure experiments on board unmanned satellite FOTON are presented.

LCMS analysis of fingerprints, the amino acid profile of 20 donors.

PubMed

de Puit, Marcel; Ismail, Mahado; Xu, Xiaoma

2014-03-01

The analysis of amino acids present in fingerprints has been studied several times. In this paper, we report a method for the analysis of amino acids using an fluorenylmethyloxycarbonyl chloride-derivatization for LC separation and MS detection. We have obtained good results with regard to the calibration curves and the limit of detection and LOQ for the target compounds. The extraction of the amino acids from the substrates used proved to be very efficient. Analysis of the derivatized amino acids enabled us to obtain full amino acid profiles for 20 donors. The intervariability is as expected rather large, with serine as the most abundant constituent, and when examining the total profile of the amino acids per donor, a characteristic pattern can be observed. Some amino acids were not detected in some donors, or fell out of the range of the calibration curve, where others showed a surprisingly high amount of material in the deposition analyses. Further investigations will have to address the intravariability of the amino acid profiles of the fingerprints from donors. By the development of the analytical method and the application to the analysis of fingerprints, we were able to gain insight in the variability of the constituents of fingerprints between the donors. © 2013 American Academy of Forensic Sciences.

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).

Anaerobic degradation of amino acids generated from the hydrolysis of sewage sludge.

PubMed

Park, Junghoon; Park, Seyong; Kim, Moonil

2014-01-01

The anaerobic degradation of each amino acid that could be generated through the hydrolysis of sewage sludge was evaluated. Stickland reaction as an intermediate reaction between two kinds of amino acids was restricted in order to evaluate each amino acid. Changes in the chemical oxygen demand (COD), T-N, NH4(+)-N, biogas, and CH4 were analysed for the anaerobic digestion process. The initial nitrogen concentration of all amino acids is adjusted as 1000 mg/L. The degradation rate of the amino acids was determined based on the ammonia form of nitrogen, which is generated by the deamination of amino acids. Among all amino acids, such as alpha-alanine, beta-alanine, lysine, arginine, glycine, histidine, cysteine, methionine, and leucine, deamination rates of cysteine, leucine, and methionine were just 61.55%, 54.59%, and 46.61%, respectively, and they had low removal rates of organic matter and showed very low methane production rates of 13.55, 71.04, and 80.77 mL CH4/g CODin, respectively. Especially for cysteine, the methane content was maintained at approximately 7% during the experiment. If wastewater contains high levels of cysteine, leucine, and methionine and Stickland reaction is not prepared, these amino acids may reduce the efficiency of the anaerobic digestion.

Oral branched-chain amino acids decrease whole-body proteolysis

NASA Technical Reports Server (NTRS)

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

1995-01-01

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

Reference intervals for plasma-free amino acid in a Japanese population.

PubMed

Yamamoto, Hiroyuki; Kondo, Kazuhiro; Tanaka, Takayuki; Muramatsu, Takahiko; Yoshida, Hiroo; Imaizumi, Akira; Nagao, Kenji; Noguchi, Yasushi; Miyano, Hiroshi

2016-05-01

Plasma amino acid concentrations vary with various diseases. Although reference intervals are useful in daily clinical practice, no reference intervals have been reported for plasma amino acids in a large Japanese population. Reference individuals were selected from 7685 subjects examined with the Japanese Ningen Dock in 2008. A total of 1890 individuals were selected based on exclusion criteria, and the reference samples were selected after the outlier samples for each amino acid concentration were excluded. The lower limit of the reference intervals for the plasma amino acid concentrations was set at the 2.5th percentile and the upper limit at the 97.5th percentile. By use of the nested analysis of variance, we analysed a large dataset of plasma samples and the effects of background factors (sex, age and body mass index [BMI]) on the plasma amino acid concentrations. Most amino acid concentrations were related to sex, especially those of branched-chained amino acid. The citrulline, glutamine, ornithine and lysine concentrations were related to age. The glutamate concentration was related to body mass index. The concentrations of most amino acids are more strongly related to sex than to age or body mass index. Our results indicate that the reference intervals for plasma amino acid concentrations should be stratified by sex when the background factors of age and body mass index are considered. © The Author(s) 2015 Reprints and permissions: sagepub.co.uk/journalsPermissions.nav.

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.

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

PubMed Central

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 H2O2, 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. PMID:29867842

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.

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

PubMed

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

2005-10-15

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

Amino acids in the cultivation of mammalian cells.

PubMed

Salazar, Andrew; Keusgen, Michael; von Hagen, Jörg

2016-05-01

Amino acids are crucial for the cultivation of mammalian cells. This importance of amino acids was realized soon after the development of the first cell lines, and a solution of a mixture of amino acids has been supplied to cultured cells ever since. The importance of amino acids is further pronounced in chemically defined mammalian cell culture media, making the consideration of their biological and chemical properties necessary. Amino acids concentrations have been traditionally adjusted to their cellular consumption rates. However, since changes in the metabolic equilibrium of amino acids can be caused by changes in extracellular concentrations, metabolomics in conjunction with flux balance analysis is being used in the development of culture media. The study of amino acid transporters is also gaining importance since they control the intracellular concentrations of these molecules and are influenced by conditions in cell culture media. A better understanding of the solubility, stability, dissolution kinetics, and interactions of these molecules is needed for an exploitation of these properties in the development of dry powdered chemically defined media for mammalian cells. Due to the complexity of these mixtures however, this has proven to be challenging. Studying amino acids in mammalian cell culture media will help provide a better understanding of how mammalian cells in culture interact with their environment. It would also provide insight into the chemical behavior of these molecules in solutions of complex mixtures, which is important in the understanding of the contribution of individual amino acids to protein structure.

[Plasma amino acids profile of healthy pregnant adolescents in Maracaibo, Venezuela].

PubMed

Ortega, Pablo; Castejón, Haydée V; Argotte, María G; Gómez, Gisela; Bohorquez, Lissette; Urrieta, Jesús R

2003-06-01

One hundred female adolescents (13-18 y) were clinical and anthropometrically studied to select only those with adequate nutrition. Most adolescents belonged to IV socio-economic stratum families (worker class). Height, weight, age, body mass index and medial arm circumference were used as anthropometric parameters. After screening, only 41 non pregnant girls (control) and 42 pregnant girls with adequate nutrition were selected to analyze plasma amino acids. Fasting peripheral venous blood was drawn, and plasma amino acids were analyzed by HPLC. Amino acid concentrations were expressed as umol/L +/- SE. SAS/STAT program was used for statistical analysis. Amino acid values of control adolescent group were found in ranges reported by other investigators, with slight variations, mostly in diminution, presumably due to nutritional, metabolic or genetic conditions of people living in tropical regions. In pregnant healthy adolescents, distributed according to gestational age: < 32 weeks (n = 30) and > 32 weeks (n = 12), a diminution of total molar plasma amino acids was found, by comparing with control values. Ten amino acids (Pro, Gly, Gln, Arg, Ser, Orn, Tau, Leu, Thr and Val) appeared significantively diminished throughout gestation, being Gly. Gln and Arg most affected since earlier weeks. During the 2nd period. Thr and Val increased their grade of affectation; whereas some amino acids values (Orn, Pro and Tau) tended to recuperate. Several of affected amino acids are gluconegoenic, thus, they could be utilized to supply the energy required by the pregnant adolescent against her double stress: the fetus development and her own development. The plasma amino acid values reported in both, healthy non pregnant and pregnant adolescents, could be taken as regional referential profile of plasma amino acids in this poblational group for further research on adolescent and fetal--maternal malnutrition.

Facilitated transporters mediate net efflux of amino acids to the fetus across the basal membrane of the placental syncytiotrophoblast

PubMed Central

Cleal, J K; Glazier, J D; Ntani, G; Crozier, S R; Day, P E; Harvey, N C; Robinson, S M; Cooper, C; Godfrey, K M; Hanson, M A; Lewis, R M

2011-01-01

Fetal growth depends on placental transfer of amino acids from maternal to fetal blood. The mechanisms of net amino acid efflux across the basal membrane (BM) of the placental syncytiotrophoblast to the fetus, although vital for amino acid transport, are poorly understood. We examined the hypothesis that facilitated diffusion by the amino acid transporters TAT1, LAT3 and LAT4 plays an important role in this process, with possible effects on fetal growth. Amino acid transfer was measured in isolated perfused human placental cotyledons (n= 5 per experiment) using techniques which distinguish between different transport processes. Placental TAT1, LAT3 and LAT4 proteins were measured, and mRNA expression levels (measured using real-time quantitative-PCR) were related to fetal and neonatal anthropometry and dual-energy X-ray absorptiometry measurements of neonatal lean mass in 102 Southampton Women's Survey (SWS) infants. Under conditions preventing transport by amino acid exchangers, all amino acids appearing in the fetal circulation were substrates of TAT1, LAT3 or LAT4. Western blots demonstrated the presence of TAT1, LAT3 and LAT4 in placental BM preparations. Placental TAT1 and LAT3 mRNA expression were positively associated with measures of fetal growth in SWS infants (P < 0.05). We provide evidence that the efflux transporters TAT1, LAT3 and LAT4 are present in the human placental BM, and may play an important role in the net efflux of amino acids to the fetus. Unlike other transporters they can increase fetal amino acid concentrations. Consistent with a role in placental amino acid transfer capacity and fetal growth TAT1 and LAT3 mRNA expression showed positive associations with infant size at birth. PMID:21224231

Compound-specific carbon, nitrogen, and hydrogen isotopic ratios for amino acids in CM and CR chondrites and their use in evaluating potential formation pathways

NASA Astrophysics Data System (ADS)

Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

2012-09-01

Stable hydrogen, carbon, and nitrogen isotopic ratios (δD, δ13C, and δ15N) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1/2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CR2 Graves Nunataks (GRA) 95229, CR2 Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing δ13C and increasing δD with increasing carbon number in the α-H, α-NH2 amino acids that correspond to predictions made for formation via Strecker-cyanohydrin synthesis. We also observe light δ13C signatures for β-alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ω-amino acids). Higher deuterium enrichments are observed in α-methyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than in CM chondrites, reflecting different parent-body chemistry.

Compound-Specific Carbon, Nitrogen, and Hydrogen Isotopic Ratios for Amino Acids in CM and CR Chondrites and their use in Evaluating Potential Formation Pathways

NASA Technical Reports Server (NTRS)

Elsila, Jamie E.; Charnley, Steven B.; Burton, Aaron S.; Glavin, Daniel P.; Dworkin, Jason P.

2012-01-01

Stable hydrogen, carbon, and nitrogen isotopic ratios (oD, 013C, and olSN) of organic compounds can revcal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may indicate the most likely of these pathways. We have applied gas chromatography with mass spectrometry and combustion isotope ratio mass spectrometry to measure the compound-specific C, N, and H stable isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites: CM1I2 Allan Hills (ALH) 83100, CM2 Murchison, CM2 Lewis Cliff (LEW) 90500, CM2 Lonewolf Nunataks (LON) 94101, CRZ Graves Nunataks (GRA) 95229, CRZ Elephant Moraine (EET) 92042, and CR3 Queen Alexandra Range (QUE) 99177. We compare the isotopic compositions of amino acids in these meteorites with predictions of expected isotopic enrichments from potential formation pathways. We observe trends of decreasing ODC and increasing oD with increasing carbon number in the aH, (l-NH2 amino acids that correspond to predictions made for formation via Streckercyanohydrin synthesis. We also observe light ODC signatures for -alanine, which may indicate either formation via Michael addition or via a pathway that forms primarily small, straight-chain, amine-terminal amino acids (n-ro-amino acids). Higher deuterium enrichments are observed in amethyl amino acids, indicating formation of these amino acids or their precursors in cold interstellar or nebular environments. Finally, individual amino acids are more enriched in deuterium in CR chondrites than CM chondrites, reflecting different parent-body chemistry.

DNA methylation of amino acid transporter genes in the human placenta.

PubMed

Simner, C; Novakovic, B; Lillycrop, K A; Bell, C G; Harvey, N C; Cooper, C; Saffery, R; Lewis, R M; Cleal, J K

2017-12-01

Placental transfer of amino acids via amino acid transporters is essential for fetal growth. Little is known about the epigenetic regulation of amino acid transporters in placenta. This study investigates the DNA methylation status of amino acid transporters and their expression across gestation in human placenta. BeWo cells were treated with 5-aza-2'-deoxycytidine to inhibit methylation and assess the effects on amino acid transporter gene expression. The DNA methylation levels of amino acid transporter genes in human placenta were determined across gestation using DNA methylation array data. Placental amino acid transporter gene expression across gestation was also analysed using data from publically available Gene Expression Omnibus data sets. The expression levels of these transporters at term were established using RNA sequencing data. Inhibition of DNA methylation in BeWo cells demonstrated that expression of specific amino acid transporters can be inversely associated with DNA methylation. Amino acid transporters expressed in term placenta generally showed low levels of promoter DNA methylation. Transporters with little or no expression in term placenta tended to be more highly methylated at gene promoter regions. The transporter genes SLC1A2, SLC1A3, SLC1A4, SLC7A5, SLC7A11 and SLC7A10 had significant changes in enhancer DNA methylation across gestation, as well as gene expression changes across gestation. This study implicates DNA methylation in the regulation of amino acid transporter gene expression. However, in human placenta, DNA methylation of these genes remains low across gestation and does not always play an obvious role in regulating gene expression, despite clear evidence for differential expression as gestation proceeds. Copyright © 2017. Published by Elsevier Ltd.

Optical backbone-sidechain charge transfer transitions in proteins sensitive to secondary structure and modifications.

PubMed

Mandal, I; Paul, S; Venkatramani, R

2018-04-17

The absorption of light by proteins can induce charge transfer (CT) transitions in the UV-visible range of the electromagnetic spectrum. Metal-ligand complexes or active site prosthetic groups which absorb in the visible region exhibit prominent CT transitions. Furthermore, the protein backbone also exhibits CT transitions in the far UV range. In this manuscript, we present a detailed computational study of new near UV-visible CT transitions that involve amino acids with charged side chains. Specifically, using time dependent density functional theory calculations, we examine the absorption spectra of naturally charged amino acids (Lys, Glu, Arg, Asp and His), extracted from solution phase protein structures generated by classical molecular dynamics simulations, and phosphorylated amino acids (Tyr, Thr and Ser) from experimentally determined protein structures. We show that amino acids with charged sidechains present a directed electronic donor-bridge-acceptor paradigm, with the lowest energy optical excitations demonstrating peptide backbone-sidechain charge separations. The UV-visible spectral range of the backbone-sidechain CT transitions is determined by the chemical nature of the donor, bridge and acceptor groups within each amino acid, amino acid conformation and the protein secondary structure where the amino acids are located. Photoinduced CT occurs in opposite directions for the anionic and cationic amino acids along the ground state dipole moment vector for the chromophores. We find that photoinduced charge separation is more facile for the anionic amino acids (Asp, Glu, pSer, pThr and pTyr) relative to that for the cationic amino acids (Lys, Arg and Hsp). Our results provide a foundation for the development of spectroscopic markers based on the recently proposed Protein Charge Transfer Spectra (ProCharTS) which are relevant for the study of DNA-binding or intrinsically disordered proteins that are rich in charged amino acids.

Branched-chain and aromatic amino acids are predictors of insulin resistance in young adults.

PubMed

Würtz, Peter; Soininen, Pasi; Kangas, Antti J; Rönnemaa, Tapani; Lehtimäki, Terho; Kähönen, Mika; Viikari, Jorma S; Raitakari, Olli T; Ala-Korpela, Mika

2013-03-01

Branched-chain and aromatic amino acids are associated with the risk for future type 2 diabetes; however, the underlying mechanisms remain elusive. We tested whether amino acids predict insulin resistance index in healthy young adults. Circulating isoleucine, leucine, valine, phenylalanine, tyrosine, and six additional amino acids were quantified in 1,680 individuals from the population-based Cardiovascular Risk in Young Finns Study (baseline age 32 ± 5 years; 54% women). Insulin resistance was estimated by homeostasis model assessment (HOMA) at baseline and 6-year follow-up. Amino acid associations with HOMA of insulin resistance (HOMA-IR) and glucose were assessed using regression models adjusted for established risk factors. We further examined whether amino acid profiling could augment risk assessment of insulin resistance (defined as 6-year HOMA-IR >90th percentile) in early adulthood. Isoleucine, leucine, valine, phenylalanine, and tyrosine were associated with HOMA-IR at baseline and for men at 6-year follow-up, while for women only leucine, valine, and phenylalanine predicted 6-year HOMA-IR (P < 0.05). None of the other amino acids were prospectively associated with HOMA-IR. The sum of branched-chain and aromatic amino acid concentrations was associated with 6-year insulin resistance for men (odds ratio 2.09 [95% CI 1.38-3.17]; P = 0.0005); however, including the amino acid score in prediction models did not improve risk discrimination. Branched-chain and aromatic amino acids are markers of the development of insulin resistance in young, normoglycemic adults, with most pronounced associations for men. These findings suggest that the association of branched-chain and aromatic amino acids with the risk for future diabetes is at least partly mediated through insulin resistance.

Comparative characterization of random-sequence proteins consisting of 5, 12, and 20 kinds of amino acids

PubMed Central

Tanaka, Junko; Doi, Nobuhide; Takashima, Hideaki; Yanagawa, Hiroshi

2010-01-01

Screening of functional proteins from a random-sequence library has been used to evolve novel proteins in the field of evolutionary protein engineering. However, random-sequence proteins consisting of the 20 natural amino acids tend to aggregate, and the occurrence rate of functional proteins in a random-sequence library is low. From the viewpoint of the origin of life, it has been proposed that primordial proteins consisted of a limited set of amino acids that could have been abundantly formed early during chemical evolution. We have previously found that members of a random-sequence protein library constructed with five primitive amino acids show high solubility (Doi et al., Protein Eng Des Sel 2005;18:279–284). Although such a library is expected to be appropriate for finding functional proteins, the functionality may be limited, because they have no positively charged amino acid. Here, we constructed three libraries of 120-amino acid, random-sequence proteins using alphabets of 5, 12, and 20 amino acids by preselection using mRNA display (to eliminate sequences containing stop codons and frameshifts) and characterized and compared the structural properties of random-sequence proteins arbitrarily chosen from these libraries. We found that random-sequence proteins constructed with the 12-member alphabet (including five primitive amino acids and positively charged amino acids) have higher solubility than those constructed with the 20-member alphabet, though other biophysical properties are very similar in the two libraries. Thus, a library of moderate complexity constructed from 12 amino acids may be a more appropriate resource for functional screening than one constructed from 20 amino acids. PMID:20162614

Purification, characterization, gene cloning and nucleotide sequencing of D: -stereospecific amino acid amidase from soil bacterium: Delftia acidovorans.

PubMed

Hongpattarakere, Tipparat; Komeda, Hidenobu; Asano, Yasuhisa

2005-12-01

The D-amino acid amidase-producing bacterium was isolated from soil samples using an enrichment culture technique in medium broth containing D-phenylalanine amide as a sole source of nitrogen. The strain exhibiting the strongest activity was identified as Delftia acidovorans strain 16. This strain produced intracellular D-amino acid amidase constitutively. The enzyme was purified about 380-fold to homogeneity and its molecular mass was estimated to be about 50 kDa, on sodium dodecyl sulfate polyacrylamide gel electrophoresis. The enzyme was active preferentially toward D-amino acid amides rather than their L-counterparts. It exhibited strong amino acid amidase activity toward aromatic amino acid amides including D-phenylalanine amide, D-tryptophan amide and D-tyrosine amide, yet it was not specifically active toward low-molecular-weight D-amino acid amides such as D-alanine amide, L-alanine amide and L-serine amide. Moreover, it was not specifically active toward oligopeptides. The enzyme showed maximum activity at 40 degrees C and pH 8.5 and appeared to be very stable, with 92.5% remaining activity after the reaction was performed at 45 degrees C for 30 min. However, it was mostly inactivated in the presence of phenylmethanesulfonyl fluoride or Cd2+, Ag+, Zn2+, Hg2+ and As3+ . The NH2 terminal and internal amino acid sequences of the enzyme were determined; and the gene was cloned and sequenced. The enzyme gene damA encodes a 466-amino-acid protein (molecular mass 49,860.46 Da); and the deduced amino acid sequence exhibits homology to the D-amino acid amidase from Variovorax paradoxus (67.9% identity), the amidotransferase A subunit from Burkholderia fungorum (50% identity) and other enantioselective amidases.

Amino acid and glucose uptake by rat brown adipose tissue. Effect of cold-exposure and acclimation.

PubMed Central

López-Soriano, F J; Fernández-López, J A; Mampel, T; Villarroya, F; Iglesias, R; Alemany, M

1988-01-01

The net uptake/release of glucose, lactate and amino acids from the bloodstream by the interscapular brown adipose tissue of control, cold-exposed and cold-acclimated rats was estimated by measurement of arteriovenous differences in their concentrations. In the control animals amino acids contributed little to the overall energetic needs of the tissue; glucose uptake was more than compensated by lactate efflux. Cold-exposure resulted in an enhancement of amino acid utilization and of glucose uptake, with high lactate efflux. There was a net glycine and proline efflux that partly compensated the positive nitrogen balance of the tissue; amino acids accounted for about one-third of the energy supplied by glucose to the tissue. Cold-acclimation resulted in a very high increase in glucose uptake, with a parallel decrease in lactate efflux and amino acid consumption. Branched-chain amino acids, however, were more actively utilized. This was related with a much higher alanine efflux, in addition to that of glycine and proline. It is suggested that most of the glucose used during cold-exposure is returned to the bloodstream as lactate under conditions of active lipid utilization, amino acids contributing their skeletons largely in anaplerotic pathways. On the other hand, cold-acclimation resulted in an important enhancement of glucose utilization, with lowered amino acid oxidation. Amino acids are thus used as metabolic substrates by the brown adipose tissue of rats under conditions of relatively scarce substrate availability, but mainly as anaplerotic substrates, in parallel to glucose. Cold-acclimation results in a shift of the main substrates used in thermogenesis from lipid to glucose, with a much lower need for amino acids. PMID:3421924

Extraterrestrial amino acids identified in metal-rich CH and CB carbonaceous chondrites from Antarctica

NASA Astrophysics Data System (ADS)

Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

2013-03-01

Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondrites but are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment (PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675 (CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratio mass spectrometry. The δ13C/12C ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (13-16 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.2-2 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of β-, γ-, and δ-amino acids compared to the corresponding α-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

Differential regulation of protein synthesis by amino acids and insulin in peripheral and visceral tissues of neonatal pigs

PubMed Central

Suryawan, Agus; O’Connor, Pamela M. J.; Bush, Jill A.; Nguyen, Hanh V.

2009-01-01

The high efficiency of protein deposition during the neonatal period is driven by high rates of protein synthesis, which are maximally stimulated after feeding. In the current study, we examined the individual roles of amino acids and insulin in the regulation of protein synthesis in peripheral and visceral tissues of the neonate by performing pancreatic glucose–amino acid clamps in overnight-fasted 7-day-old pigs. We infused pigs (n = 8–12/group) with insulin at 0, 10, 22, and 110 ng kg−0.66 min−1 to achieve ~0, 2, 6 and 30 μU ml−1 insulin so as to simulate below fasting, fasting, intermediate, and fed insulin levels, respectively. At each insulin dose, amino acids were maintained at the fasting or fed level. In conjunction with the highest insulin dose, amino acids were also allowed to fall below the fasting level. Tissue protein synthesis was measured using a flooding dose of L-[4-3H] phenylalanine. Both insulin and amino acids increased fractional rates of protein synthesis in longissimus dorsi, gastrocnemius, masseter, and diaphragm muscles. Insulin, but not amino acids, increased protein synthesis in the skin. Amino acids, but not insulin, increased protein synthesis in the liver, pancreas, spleen, and lung and tended to increase protein synthesis in the jejunum and kidney. Neither insulin nor amino acids altered protein synthesis in the stomach. The results suggest that the stimulation of protein synthesis by feeding in most tissues of the neonate is regulated by the post-prandial rise in amino acids. However, the feeding-induced stimulation of protein synthesis in skeletal muscles is independently mediated by insulin as well as amino acids. PMID:18683020

Amino acids augment muscle protein synthesis in neonatal pigs during acute endotoxemia by stimulating mTOR-dependent translation initiation.

PubMed

Orellana, Renán A; Jeyapalan, Asumthia; Escobar, Jeffery; Frank, Jason W; Nguyen, Hanh V; Suryawan, Agus; Davis, Teresa A

2007-11-01

In skeletal muscle of adults, sepsis reduces protein synthesis by depressing translation initiation and induces resistance to branched-chain amino acid stimulation. Normal neonates maintain a high basal muscle protein synthesis rate that is sensitive to amino acid stimulation. In the present study, we determined the effect of amino acids on protein synthesis in skeletal muscle and other tissues in septic neonates. Overnight-fasted neonatal pigs were infused with endotoxin (LPS, 0 and 10 microg.kg(-1).h(-1)), whereas glucose and insulin were maintained at fasting levels; amino acids were clamped at fasting or fed levels. In the presence of fasting insulin and amino acids, LPS reduced protein synthesis in longissimus dorsi (LD) and gastrocnemius muscles and increased protein synthesis in the diaphragm, but had no effect in masseter and heart muscles. Increasing amino acids to fed levels accelerated muscle protein synthesis in LD, gastrocnemius, masseter, and diaphragm. LPS stimulated protein synthesis in liver, lung, spleen, pancreas, and kidney in fasted animals. Raising amino acids to fed levels increased protein synthesis in liver of controls, but not LPS-treated animals. The increase in muscle protein synthesis in response to amino acids was associated with increased mTOR, 4E-BP1, and S6K1 phosphorylation and eIF4G-eIF4E association in control and LPS-infused animals. These findings suggest that amino acids stimulate skeletal muscle protein synthesis during acute endotoxemia via mTOR-dependent ribosomal assembly despite reduced basal protein synthesis rates in neonatal pigs. However, provision of amino acids does not further enhance the LPS-induced increase in liver protein synthesis.

Extraterrestrial Amino Acids Identified in Metal-Rich CH and CB Carbonaceous Chondrites from Antarctica

NASA Technical Reports Server (NTRS)

Burton, Aaron S.; Elsila, Jamie E.; Hein, Jason E.; Glavin, Daniel P.; Dworkin, Jason P.

2013-01-01

Carbonaceous chondrites contain numerous indigenous organic compounds and could have been an important source of prebiotic compounds required for the origin of life on Earth or elsewhere. Extraterrestrial amino acids have been reported in five of the eight groups of carbonaceous chondrites and are most abundant in CI, CM, and CR chondritesbut are also present in the more thermally altered CV and CO chondrites. We report the abundance, distribution, and enantiomeric and isotopic compositions of simple primary amino acids in six metal-rich CH and CB carbonaceous chondrites that have not previously been investigated for amino acids: Allan Hills (ALH) 85085 (CH3), Pecora Escarpment(PCA) 91467 (CH3), Patuxent Range (PAT) 91546 (CH3), MacAlpine Hills (MAC) 02675(CBb), Miller Range (MIL) 05082 (CB), and Miller Range (MIL) 07411 (CB). Amino acid abundances and carbon isotopic values were obtained by using both liquid chromatography time-of-flight mass spectrometry and fluorescence, and gas chromatography isotope ratiomass spectrometry. The (delta D, delta C-13, delta N-15) ratios of multiple amino acids fall outside of the terrestrial range and support their extraterrestrial origin. Extracts of CH chondrites were found to be particularly rich in amino acids (1316 parts per million, ppm) while CB chondrite extracts had much lower abundances (0.22 ppm). The amino acid distributions of the CH and CB chondrites were distinct from the distributions observed in type 2 and 3 CM and CR chondrites and contained elevated levels of beta-, gamma-, and delta-amino acids compared to the corresponding alpha-amino acids, providing evidence that multiple amino acid formation mechanisms were important in CH and CB chondrites.

[Amino acid level in pastry with low caloric value].

PubMed

Barkhatov, V Iu; Vyskubova, N K; Felipas, T B; Pshemurzova, R M; Kamenetskaia, E V

1988-01-01

The effect of fruit paste additives on amino acid composition of farinaceous and decorative confectionery semifinished products was studied to decrease their fuel value. It was found that a partial replacement of sugar and fat for apple and quince pastes in apple biscuit and apple shortbread semiproducts led to an increase in the content of essential and sulfur-containing amino acids. Cream prepared from egg albumin and quince paste had reduced content of amino acids (except for glutamic acid) due to the diminished content of egg albumin, however, the balance of amino acid composition was improved.

A rapid and efficient one-pot method for the reduction of N-protected α-amino acids to chiral α-amino aldehydes using CDI/DIBAL-H.

PubMed

Ivkovic, Jakov; Lembacher-Fadum, Christian; Breinbauer, Rolf

2015-11-14

N-Protected amino acids can be easily converted into chiral α-amino aldehydes in a one-pot reaction by activation with CDI followed by reduction with DIBAL-H. This method delivers Boc-, Cbz- and Fmoc-protected amino aldehydes from proteinogenic amino acids in very good isolated yields and complete stereointegrity.

Stability Test and Quantitative and Qualitative Analyses of the Amino Acids in Pharmacopuncture Extracted from Scolopendra subspinipes mutilans

PubMed Central

Cho, GyeYoon; Han, KyuChul; Yoon, JinYoung

2015-01-01

Objectives: Scolopendra subspinipes mutilans (S. subspinipes mutilans) is known as a traditional medicine and includes various amino acids, peptides and proteins. The amino acids in the pharmacopuncture extracted from S. subspinipes mutilans by using derivatization methods were analyzed quantitatively and qualitatively by using high performance liquid chromatography (HPLC) over a 12 month period to confirm its stability. Methods: Amino acids of pharmacopuncture extracted from S. subspinipes mutilans were derived by using O-phthaldialdehyde (OPA) & 9-fluorenyl methoxy carbonyl chloride (FMOC) reagent and were analyzed using HPLC. The amino acids were detected by using a diode array detector (DAD) and a fluorescence detector (FLD) to compare a mixed amino acid standard (STD) to the pharmacopuncture from centipedes. The stability tests on the pharmacopuncture from centipedes were done using HPLC for three conditions: a room temperature test chamber, an acceleration test chamber, and a cold test chamber. Results: The pharmacopuncture from centipedes was prepared by using the method of the Korean Pharmacopuncture Institute (KPI) and through quantitative analyses was shown to contain 9 amino acids of the 16 amino acids in the mixed amino acid STD. The amounts of the amino acids in the pharmacopuncture from centipedes were 34.37 ppm of aspartate, 123.72 ppm of arginine, 170.63 ppm of alanine, 59.55 ppm of leucine and 57 ppm of lysine. The relative standard deviation (RSD %) results for the pharmacopuncture from centipedes had a maximum value of 14.95% and minimum value of 1.795% on the room temperature test chamber, the acceleration test chamber and the cold test chamber stability tests. Conclusion: Stability tests on and quantitative and qualitative analyses of the amino acids in the pharmacopuncture extracted from centipedes by using derivatization methods were performed by using HPLC. Through research, we hope to determine the relationship between time and the concentrations of the amino acids in the pharmacopuncture extracted from centipedes. PMID:25830058

Nutritional Stress Induced by Amino Acid Starvation Results in Changes for Slc38 Transporters in Immortalized Hypothalamic Neuronal Cells and Primary Cortex Cells.

PubMed

Hellsten, Sofie V; Tripathi, Rekha; Ceder, Mikaela M; Fredriksson, Robert

2018-01-01

Amino acid sensing and signaling is vital for cells, and both gene expression and protein levels of amino acid transporters are regulated in response to amino acid availability. Here, the aim was to study the regulation of all members of the SLC38 amino acid transporter family, Slc38a1-11 , in mouse brain cells following amino acid starvation. We reanalyzed microarray data for the immortalized hypothalamic cell line N25/2 subjected to complete amino acid starvation for 1, 2, 3, 5, or 16 h, focusing specifically on the SLC38 family. All 11 Slc38 genes were expressed in the cell line, and Slc38a1, Slc38a2 , and Slc38a7 were significantly upregulated at 5 h and most strongly at 16 h. Here, protein level changes were measured for SLC38A7 and the orphan family member SLC38A11 which has not been studied under different amino acid starvation condition at protein level. At 5 h, no significant alteration on protein level for either SLC38A7 or SLC38A11 could be detected. In addition, primary embryonic cortex cells were deprived of nine amino acids, the most common amino acids transported by the SLC38 family members, for 3 h, 7 h or 12 h, and the gene expression was measured using qPCR. Slc38a1, Slc38a2, Slc38a5, Slc38a6, Slc38a9 , and Slc38a10 were upregulated, while Slc38a3 and Slc38a7 were downregulated. Slc38a8 was upregulated at 5 h and downregulated at 12 h. In conclusion, several members from the SLC38 family are regulated depending on amino acid levels and are likely to be involved in amino acid sensing and signaling in brain.

Stability Test and Quantitative and Qualitative Analyses of the Amino Acids in Pharmacopuncture Extracted from Scolopendra subspinipes mutilans.

PubMed

Cho, GyeYoon; Han, KyuChul; Yoon, JinYoung

2015-03-01

Scolopendra subspinipes mutilans (S. subspinipes mutilans) is known as a traditional medicine and includes various amino acids, peptides and proteins. The amino acids in the pharmacopuncture extracted from S. subspinipes mutilans by using derivatization methods were analyzed quantitatively and qualitatively by using high performance liquid chromatography (HPLC) over a 12 month period to confirm its stability. Amino acids of pharmacopuncture extracted from S. subspinipes mutilans were derived by using O-phthaldialdehyde (OPA) & 9-fluorenyl methoxy carbonyl chloride (FMOC) reagent and were analyzed using HPLC. The amino acids were detected by using a diode array detector (DAD) and a fluorescence detector (FLD) to compare a mixed amino acid standard (STD) to the pharmacopuncture from centipedes. The stability tests on the pharmacopuncture from centipedes were done using HPLC for three conditions: a room temperature test chamber, an acceleration test chamber, and a cold test chamber. The pharmacopuncture from centipedes was prepared by using the method of the Korean Pharmacopuncture Institute (KPI) and through quantitative analyses was shown to contain 9 amino acids of the 16 amino acids in the mixed amino acid STD. The amounts of the amino acids in the pharmacopuncture from centipedes were 34.37 ppm of aspartate, 123.72 ppm of arginine, 170.63 ppm of alanine, 59.55 ppm of leucine and 57 ppm of lysine. The relative standard deviation (RSD %) results for the pharmacopuncture from centipedes had a maximum value of 14.95% and minimum value of 1.795% on the room temperature test chamber, the acceleration test chamber and the cold test chamber stability tests. Stability tests on and quantitative and qualitative analyses of the amino acids in the pharmacopuncture extracted from centipedes by using derivatization methods were performed by using HPLC. Through research, we hope to determine the relationship between time and the concentrations of the amino acids in the pharmacopuncture extracted from centipedes.

Gas chromatographic determination and mechanism of formation of D-amino acids occurring in fermented and roasted cocoa beans, cocoa powder, chocolate and cocoa shell.

PubMed

Pätzold, R; Brückner, H

2006-07-01

Fermented cocoa beans of various countries of origin (Ivory Coast, Ghana, Sulawesi), cocoa beans roasted under defined conditions (100-150 degrees C; 30-120 min), low and high fat cocoa powder, various brands of chocolate, and cocoa shells were analyzed for their contents of free L-and D-amino acids. Amino acids were isolated from defatted products using a cation exchanger and converted into volatile N(O)-pentafluoropropionyl amino acid 2-propyl esters which were analyzed by enantioselective gas chromatography mass spectrometry on a Chirasil-L-Val capillary column. Besides common protein L-amino acids low amounts of D-amino acids were detected in fermented cocoa beans. Quantities of D-amino acids increased on heating. On roasting cocoa beans of the Forastero type from the Ivory Coast at 150 degrees C for 2 h, relative quantities of D-amino acids approached 17.0% D-Ala, 11.7% D-Ile, 11.1% D-Asx (Asp + Asn), 7.9% D-Tyr, 5.8% D-Ser, 4.8% D-Leu, 4.3% D-Phe, 37.0% D-Pro, and 1.2% D-Val. In cocoa powder and chocolate relative quantities amounted to 14.5% D-Ala, 10.6% D-Tyr, 9.8% D-Phe, 8.1% L-Asx, and 7.2% D-Ile. Lower quantities of other D-amino acids were also detected. In order to corroborate our hypothesis that D-amino acids are generated from Amadori compounds (fructose amino acids) formed in the course of the Maillard reaction, fructose-L-phenylalanine and fructose-D-phenylalanine were synthesized and heated at 200 degrees C for 5-60 min. Already after 5 min release of 11.7% D-Phe and 11.8% L-Phe in the free form could be analyzed. Based on the data a racemization mechanism is presented founded on the intermediate and reversible formation of an amino acid carbanion in the Amadori compounds.

A nine-country study of the protein content and amino acid composition of mature human milk

PubMed Central

Feng, Ping; Gao, Ming; Burgher, Anita; Zhou, Tian Hui; Pramuk, Kathryn

2016-01-01

Background Numerous studies have evaluated protein and amino acid levels in human milk. However, research in this area has been limited by small sample sizes and study populations with little ethnic or racial diversity. Objective Evaluate the protein and amino acid composition of mature (≥30 days) human milk samples collected from a large, multinational study using highly standardized methods for sample collection, storage, and analysis. Design Using a single, centralized laboratory, human milk samples from 220 women (30–188 days postpartum) from nine countries were analyzed for amino acid composition using Waters AccQ-Tag high-performance liquid chromatography and total nitrogen content using the LECO FP-528 nitrogen analyzer. Total protein was calculated as total nitrogen×6.25. True protein, which includes protein, free amino acids, and peptides, was calculated from the total amino acids. Results Mean total protein from individual countries (standard deviation [SD]) ranged from 1,133 (125.5) to 1,366 (341.4) mg/dL; the mean across all countries (SD) was 1,192 (200.9) mg/dL. Total protein, true protein, and amino acid composition were not significantly different across countries except Chile, which had higher total and true protein. Amino acid profiles (percent of total amino acids) did not differ across countries. Total and true protein concentrations and 16 of 18 amino acid concentrations declined with the stage of lactation. Conclusions Total protein, true protein, and individual amino acid concentrations in human milk steadily decline from 30 to 151 days of lactation, and are significantly higher in the second month of lactation compared with the following 4 months. There is a high level of consistency in the protein content and amino acid composition of human milk across geographic locations. The size and diversity of the study population and highly standardized procedures for the collection, storage, and analysis of human milk support the validity and broad application of these findings. PMID:27569428

Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle.

PubMed

Reidy, P T; Walker, D K; Dickinson, J M; Gundermann, D M; Drummond, M J; Timmerman, K L; Cope, M B; Mukherjea, R; Jennings, K; Volpi, E; Rasmussen, B B

2014-06-01

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups (P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein (P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein. Copyright © 2014 the American Physiological Society.

Soy-dairy protein blend and whey protein ingestion after resistance exercise increases amino acid transport and transporter expression in human skeletal muscle

PubMed Central

Reidy, P. T.; Walker, D. K.; Dickinson, J. M.; Gundermann, D. M.; Drummond, M. J.; Timmerman, K. L.; Cope, M. B.; Mukherjea, R.; Jennings, K.; Volpi, E.

2014-01-01

Increasing amino acid availability (via infusion or ingestion) at rest or postexercise enhances amino acid transport into human skeletal muscle. It is unknown whether alterations in amino acid availability, from ingesting different dietary proteins, can enhance amino acid transport rates and amino acid transporter (AAT) mRNA expression. We hypothesized that the prolonged hyperaminoacidemia from ingesting a blend of proteins with different digestion rates postexercise would enhance amino acid transport into muscle and AAT expression compared with the ingestion of a rapidly digested protein. In a double-blind, randomized clinical trial, we studied 16 young adults at rest and after acute resistance exercise coupled with postexercise (1 h) ingestion of either a (soy-dairy) protein blend or whey protein. Phenylalanine net balance and transport rate into skeletal muscle were measured using stable isotopic methods in combination with femoral arteriovenous blood sampling and muscle biopsies obtained at rest and 3 and 5 h postexercise. Phenylalanine transport into muscle and mRNA expression of select AATs [system L amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, system A amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, cationic amino acid transporter 1/SLC7A1] increased to a similar extent in both groups (P < 0.05). However, the ingestion of the protein blend resulted in a prolonged and positive net phenylalanine balance during postexercise recovery compared with whey protein (P < 0.05). Postexercise myofibrillar protein synthesis increased similarly between groups. We conclude that, while both protein sources enhanced postexercise AAT expression, transport into muscle, and myofibrillar protein synthesis, postexercise ingestion of a protein blend results in a slightly prolonged net amino acid balance across the leg compared with whey protein. PMID:24699854

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 ).

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

Amino acid composition and antioxidant capacity of Spanish honeys.

PubMed

Pérez, Rosa Ana; Iglesias, María Teresa; Pueyo, Encarnación; Gonzalez, Montserrat; de Lorenzo, Cristina

2007-01-24

The amino acid composition of 53 honey samples from Spain, consisting of 39 floral, 5 honeydew, and 9 blend honeys, has been determined. Physicochemical characteristics, polyphenolic content, amino acid composition, and estimation of the radical scavenging capacity against the stable free radical DPPH of the honey samples were analyzed. The resulting data have been statistically evaluated. The results showed that pH, acidity, net absorbance, electrical conductivity, and total polyphenolic contents of the honeys showed a strong correlation with the radical scavenging capacity. The correlation between the radical scavenging capacity of honey and amino acid contents was high with 18 of the 20 amino acids detected, with correlation values higher than those obtained for polyphenolic content. These results suggest that the amino acid composition of honey is an indicator of the sample's scavenging capacity.

A supplemental intravenous amino acid infusion sustains a positive protein balance for 24 hours in critically ill patients.

PubMed

Sundström Rehal, Martin; Liebau, Felix; Tjäder, Inga; Norberg, Åke; Rooyackers, Olav; Wernerman, Jan

2017-12-06

Providing supplemental amino acids to ICU patients during a 3-h period results in improved whole-body net protein balance, without an increase in amino acid oxidation. The primary objective was to investigate if a 24-h intravenous amino acid infusion in critically ill patients has a sustained effect on whole-body protein balance as was seen after 3 h. Secondary objectives were monitoring of amino acid oxidation rate, urea and free amino acid plasma concentrations. An infusion of [1- 13 C]-phenylalanine was added to ongoing enteral nutrition to quantify the enteral uptake of amino acids. Primed intravenous infusions of [ring- 2 H 5 ]-phenylalanine and [3,3- 2 H 2 ]-tyrosine were used to assess whole-body protein synthesis and breakdown, to calculate net protein balance and to assess amino acid oxidation at baseline and at 3 and 24 hours. An intravenous amino acid infusion was added to nutrition at a rate of 1 g/kg/day and continued for 24 h. Eight patients were studied. The amino acid infusion resulted in improved net protein balance over time, from -1.6 ± 7.9 μmol phe/kg/h at 0 h to 6.0 ± 8.8 at 3 h and 7.5 ± 5.1 at 24 h (p = 0.0016). The sum of free amino acids in plasma increased from 3.1 ± 0.6 mmol/L at 0 h to 3.2 ± 0.3 at 3 h and 3.6 ± 0.5 at 24 h (p = 0.038). Amino acid oxidation and plasma urea were not altered significantly. We demonstrated that the improvement in whole-body net protein balance from a supplemental intravenous amino acid infusion seen after 3 h was sustained after 24 h in critically ill patients. This trial was prospectively registered at Australian New Zealand Clinical Trials Registry. ACTRN, 12615001314516 . Registered on 1 December 2015.

Extraterrestrial amino acids in Orgueil and Ivuna: Tracing the parent body of CI type carbonaceous chondrites

PubMed Central

Ehrenfreund, Pascale; Glavin, Daniel P.; Botta, Oliver; Cooper, George; Bada, Jeffrey L.

2001-01-01

Amino acid analyses using HPLC of pristine interior pieces of the CI carbonaceous chondrites Orgueil and Ivuna have found that β-alanine, glycine, and γ-amino-n-butyric acid (ABA) are the most abundant amino acids in these two meteorites, with concentrations ranging from ≈600 to 2,000 parts per billion (ppb). Other α-amino acids such as alanine, α-ABA, α-aminoisobutyric acid (AIB), and isovaline are present only in trace amounts (<200 ppb). Carbon isotopic measurements of β-alanine and glycine and the presence of racemic (D/L ≈ 1) alanine and β-ABA in Orgueil suggest that these amino acids are extraterrestrial in origin. In comparison to the CM carbonaceous chondrites Murchison and Murray, the amino acid composition of the CIs is strikingly distinct, suggesting that these meteorites came from a different type of parent body, possibly an extinct comet, than did the CM carbonaceous chondrites. PMID:11226205

Cluster shading modifies amino acids in grape (Vitis vinifera L.) berries in a genotype- and tissue-dependent manner.

PubMed

Guan, Le; Wu, Benhong; Hilbert, Ghislaine; Li, Shaohua; Gomès, Eric; Delrot, Serge; Dai, Zhanwu

2017-08-01

Amino acid composition of the grape berry at harvest is important for wine making. The present study investigates the complex interplay between tissue, cultivar and light conditions that determine berry amino acid content. Twenty amino acids were assessed in the berry skin and pulp of two grape cultivars (Gamay Noir and Gamay Fréaux), grown under either light exposure or cluster shading conditions. In all samples, cluster shading significantly reduced most amino acids, except gamma-aminobutyric acid (GABA) and phenylalanine. However, the magnitude of the decrease was stronger in the skin (67.0% decrease) than in the pulp (30.4%) and stronger in cv. Gamay Noir (69.7%) than in Gamay Fréaux (30.7%). Cluster shading also significantly modified amino acid composition by decreasing the proline content while increasing the GABA content. These results are of oenological interest for shaping the amino acid composition of the must and improving wine quality. 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.

Updates on industrial production of amino acids using Corynebacterium glutamicum.

PubMed

Wendisch, Volker F; Jorge, João M P; Pérez-García, Fernando; Sgobba, Elvira

2016-06-01

L-Amino acids find various applications in biotechnology. L-Glutamic acid and its salts are used as flavor enhancers. Other L-amino acids are used as food or feed additives, in parenteral nutrition or as building blocks for the chemical and pharmaceutical industries. L-amino acids are synthesized from precursors of central carbon metabolism. Based on the knowledge of the biochemical pathways microbial fermentation processes of food, feed and pharma amino acids have been developed. Production strains of Corynebacterium glutamicum, which has been used safely for more than 50 years in food biotechnology, and Escherichia coli are constantly improved using metabolic engineering approaches. Research towards new processes is ongoing. Fermentative production of L-amino acids in the million-ton-scale has shaped modern biotechnology and its markets continue to grow steadily. This review focusses on recent achievements in strain development for amino acid production including the use of CRISPRi/dCas9, genome-reduced strains, biosensors and synthetic pathways to enable utilization of alternative carbon sources.

On the reported optical activity of amino acids in the Murchison meteorite

USGS Publications Warehouse

Bada, J.L.; Cronin, J.R.; Ho, M.-S.; Kvenvolden, K.A.; Lawless, J.G.; Miller, S.L.; Oro, John; Steinberg, S.

1983-01-01

In analyses of extracts from the Murchison meteorite (a carbonaceous chondrite), Engel and Nagy1 reported an excess of L-enantiomers for several protein amino acids but found that the non-protein amino acids were racemic. They suggested that the excess of L-isomers might have resulted from an asymmetric synthesis or decomposition. Their results disagree with those obtained previously2-4 and they claim this is due to improved methodology. In fact, their extraction method and analytical procedure (gas chromatography-mass spectrometry, GC-MS) was similar to those used in the original report2 of amino acids in the Murchison meteorite except that they used specific ion monitoring in the GC-MS measurements. We found the results of Engel and Nagy odd in that likely contaminants (the protein amino acids ala, leu, glu, asp and pro) were nonracemic while unlikely contaminants (isovaline and ??-amino-n-butyric acid) were racemic. For example, Engel and Nagy report that the leucine is ???90% L-enantiomer in the water-extracted sample whereas isovaline (??-methyl-??-aminobutyric acid) is racemic. It would be most unusual for an abiotic stereoselective decomposition or synthesis of amino acids to occur with protein amino acids but not with non-protein amino acids. We now show here that the explanation of terrestrial contamination is consistent with their results and is much more probable. ?? 1983 Nature Publishing Group.

Conformational dynamics of L-lysine, L-arginine, L-ornithine binding protein reveals ligand-dependent plasticity.

PubMed

Silva, Daniel-Adriano; Domínguez-Ramírez, Lenin; Rojo-Domínguez, Arturo; Sosa-Peinado, Alejandro

2011-07-01

The molecular basis of multiple ligand binding affinity for amino acids in periplasmic binding proteins (PBPs) and in the homologous domain for class C G-protein coupled receptors is an unsolved question. Here, using unrestrained molecular dynamic simulations, we studied the ligand binding mechanism present in the L-lysine, L-arginine, L-ornithine binding protein. We developed an analysis based on dihedral angles for the description of the conformational changes upon ligand binding. This analysis has an excellent correlation with each of the two main movements described by principal component analysis (PCA) and it's more convenient than RMSD measurements to describe the differences in the conformational ensembles observed. Furthermore, an analysis of hydrogen bonds showed specific interactions for each ligand studied as well as the ligand interaction with the aromatic residues Tyr-14 and Phe-52. Using uncharged histidine tautomers, these interactions are not observed. On the basis of these results, we propose a model in which hydrogen bond interactions place the ligand in the correct orientation to induce a cation-π interaction with Tyr-14 and Phe-52 thereby stabilizing the closed state. Our results also show that this protein adopts slightly different closed conformations to make available specific hydrogen bond interactions for each ligand thus, allowing a single mechanism to attain multiple ligand specificity. These results shed light on the experimental evidence for ligand-dependent conformational plasticity not explained by the previous crystallographic data. Copyright © 2011 Wiley-Liss, Inc.

Structure, function and translational relevance of aquaporin dual water and ion channels.

PubMed

Yool, Andrea J; Campbell, Ewan M

2012-01-01

Aquaporins have been assumed to be selective for water alone, and aquaglyceroporins are accepted as carrying water and small uncharged solutes including glycerol. This review presents an expanded view of aquaporins as channels with more complex mechanisms of regulation and diverse repertoires of substrate permeabilities than were originally appreciated in the early establishment of the field. The role of aquaporins as dual water and gated ion channels is likely to have physiological and potentially translational relevance, and can be evaluated with newly developed molecular and pharmacological tools. Ion channel activity has been shown for Aquaporins -0, -1, and -6, Drosphila Big Brain, and plant Nodulin-26. Although the concept of ion channel function in aquaporins remains controversial, research advances are beginning to define not only the ion channel function but also the detailed molecular mechanisms that govern and mediate the multifunctional capabilities. With regard to physiological relevance, the adaptive benefit of expression of ion channel activity in aquaporins, implied by amino acid sequence conservation of the ion channel gating domains, suggests they provide more than water or glycerol and solute transport. Dual ion and water channels are of interest for understanding the modulation of transmembrane fluid gradients, volume regulation, and possible signal transduction in tissues expressing classes of aquaporins that have the dual function capability. Other aquaporin classes might be found in future work to have ion channel activities, pending identification of the possible signaling pathways that could govern activation. Copyright © 2012 Elsevier Ltd. All rights reserved.

A new subfamily LIP of the major intrinsic proteins.

PubMed

Khabudaev, Kirill Vladimirovich; Petrova, Darya Petrovna; Grachev, Mikhail Aleksandrovich; Likhoshway, Yelena Valentinovna

2014-03-04

Proteins of the major intrinsic protein (MIP) family, or aquaporins, have been detected in almost all organisms. These proteins are important in cells and organisms because they allow for passive transmembrane transport of water and other small, uncharged polar molecules. We compared the predicted amino acid sequences of 20 MIPs from several algae species of the phylum Heterokontophyta (Kingdom Chromista) with the sequences of MIPs from other organisms. Multiple sequence alignments revealed motifs that were homologous to functionally important NPA motifs and the so-called ar/R-selective filter of glyceroporins and aquaporins. The MIP sequences of the studied chromists fell into several clusters that belonged to different groups of MIPs from a wide variety of organisms from different Kingdoms. Two of these proteins belong to Plasma membrane intrinsic proteins (PIPs), four of them belong to GlpF-like intrinsic proteins (GIPs), and one of them belongs to a specific MIPE subfamily from green algae. Three proteins belong to the unclassified MIPs, two of which are of bacterial origin. Eight of the studied MIPs contain an NPM-motif in place of the second conserved NPA-motif typical of the majority of MIPs. The MIPs of heterokonts within all detected clusters can differ from other MIPs in the same cluster regarding the structure of the ar/R-selective filter and other generally conserved motifs. We proposed placing nine MIPs from heterokonts into a new group, which we have named the LIPs (large intrinsic proteins). The possible substrate specificities of the studied MIPs are discussed.

40 CFR 721.5286 - Benzenediazonium, [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol...

Code of Federal Regulations, 2010 CFR

2010-07-01

...) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted)azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized...

40 CFR 721.5286 - Benzenediazonium, [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol...

Code of Federal Regulations, 2011 CFR

2011-07-01

...) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted) azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized..., [[[[(substituted)azo]phenyl]sulfonyl]amino]-, coupled with aminophenol, diazotized aminobenzoic acid, diazotized...

21 CFR 862.1055 - Newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 8 2011-04-01 2011-04-01 false Newborn screening test system for amino acids... screening test system for amino acids, free carnitine, and acylcarnitines using tandem mass spectrometry. (a) Identification. A newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

21 CFR 862.1055 - Newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Newborn screening test system for amino acids... screening test system for amino acids, free carnitine, and acylcarnitines using tandem mass spectrometry. (a) Identification. A newborn screening test system for amino acids, free carnitine, and acylcarnitines using tandem...

Unnatural reactive amino acid genetic code additions

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

Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.

This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

Soil amino acid composition across a boreal forest successional sequence

Treesearch

Nancy R. Werdin-Pfisterer; Knut Kielland; Richard D. Boone

2009-01-01

Soil amino acids are important sources of organic nitrogen for plant nutrition, yet few studies have examined which amino acids are most prevalent in the soil. In this study, we examined the composition, concentration, and seasonal patterns of soil amino acids across a primary successional sequence encompassing a natural gradient of plant productivity and soil...

37 CFR 1.821 - Nucleotide and/or amino acid sequence disclosures in patent applications.

Code of Federal Regulations, 2014 CFR

2014-07-01

...” means those amino acids other than “Xaa” and those nucleotide bases other than “n”defined in accordance... 37 Patents, Trademarks, and Copyrights 1 2014-07-01 2014-07-01 false Nucleotide and/or amino acid... Biotechnology Invention Disclosures Application Disclosures Containing Nucleotide And/or Amino Acid Sequences...

37 CFR 1.821 - Nucleotide and/or amino acid sequence disclosures in patent applications.

Code of Federal Regulations, 2013 CFR

2013-07-01

...” means those amino acids other than “Xaa” and those nucleotide bases other than “n”defined in accordance... 37 Patents, Trademarks, and Copyrights 1 2013-07-01 2013-07-01 false Nucleotide and/or amino acid... Biotechnology Invention Disclosures Application Disclosures Containing Nucleotide And/or Amino Acid Sequences...

37 CFR 1.821 - Nucleotide and/or amino acid sequence disclosures in patent applications.

Code of Federal Regulations, 2012 CFR

2012-07-01

...” means those amino acids other than “Xaa” and those nucleotide bases other than “n”defined in accordance... 37 Patents, Trademarks, and Copyrights 1 2012-07-01 2012-07-01 false Nucleotide and/or amino acid... Biotechnology Invention Disclosures Application Disclosures Containing Nucleotide And/or Amino Acid Sequences...

Adaptation of in vivo amino acid kinetics facilitates increased amino acid availability for fetal growth in adolescent and adult pregnancies alike

USDA-ARS?s Scientific Manuscript database

During pregnancy, adult women with a normal BMI synthesize extra amino acids after an overnight fast by increasing body protein breakdown and decreasing amino acid oxidation. It is not known whether adolescent girls can make these adaptations during pregnancy. The present study aimed to measure and ...

Unnatural reactive amino acid genetic code additions

DOEpatents

Deiters, Alexander; Cropp, Ashton T; Chin, Jason W; Anderson, Christopher J; Schultz, Peter G

2013-05-21

This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

Unnatural reactive amino acid genetic code additions

DOEpatents

Deiters, Alexander [La Jolla, CA; Cropp, T Ashton [San Diego, CA; Chin, Jason W [Cambridge, GB; Anderson, J Christopher [San Francisco, CA; Schultz, Peter G [La Jolla, CA

2011-02-15

This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

Unnatural reactive amino acid genetic code additions

DOEpatents

Deiters, Alexander; Cropp, T. Ashton; Chin, Jason W.; Anderson, J. Christopher; Schultz, Peter G.

2014-08-26

This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, orthogonal pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

Unnatural reactive amino acid genetic code additions

DOEpatents

Deiters, Alexander [La Jolla, CA; Cropp, T Ashton [Bethesda, MD; Chin, Jason W [Cambridge, GB; Anderson, J Christopher [San Francisco, CA; Schultz, Peter G [La Jolla, CA

2011-08-09

This invention provides compositions and methods for producing translational components that expand the number of genetically encoded amino acids in eukaryotic cells. The components include orthogonal tRNAs, orthogonal aminoacyl-tRNAsyn-thetases, pairs of tRNAs/synthetases and unnatural amino acids. Proteins and methods of producing proteins with unnatural amino acids in eukaryotic cells are also provided.

Stardust, Supernovae and the Chirality of the Amino Acids

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

Boyd, R N; Kajino, T; Onaka, T

A mechanism for creating enantiomerism in the amino acids, the building blocks of the proteins, that involves global selection of one chirality by interactions between the amino acids and neutrinos from core-collapse supernovae is described. The selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the 14N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereofmore » on Earth, or could have triggered the chirality that was ultimately achieved for Earth's amino acids.« less

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

Enhanced amine and amino acid analysis using Pacific Blue and the Mars Organic Analyzer microchip capillary electrophoresis system.

PubMed

Chiesl, Thomas N; Chu, Wai K; Stockton, Amanda M; Amashukeli, Xenia; Grunthaner, Frank; Mathies, Richard A

2009-04-01

The fluorescent amine reactive probe Pacific Blue succinimidyl ester (PB) is used for the detection of trace amounts of amines and amino acids by microchip capillary electrophoresis on the Mars Organic Analyzer (MOA). The spectral and chemical properties of PB provide a 200-fold increase in sensitivity and improved resolution compared to fluorescamine derivatization. With the use of cross injection and PB labeling, the MOA detected amino acids at concentrations as low as 75 pM (sub-parts-per-trillion). Micellar electrokinetic chromatography (MEKC) which separates PB-labeled amino acids by their hydrophobicity is also demonstrated. The optimized MEKC conditions (45 mM CHAPSO, pH 6 at 5 degrees C) effectively separated amines and 25 amino acids with enantiomeric resolution of alanine, serine, and citrulline. Samples from the Yungay Hills region in the Atacama Desert, Chile, and from the Murchison meteorite are successfully analyzed using both techniques, and amino acids are found in the parts-per-billion range. Abiotic amino acids such as beta-alanine and epsilon-aminocaprioc acid are detected along with several neutral and acidic amino acids in the Murchison sample. The Atacama Desert sample is found to contain homochiral L-alanine and L-serine indicating the presence of extant or recently extinct life.

Comparison of the ligand binding properties of two homologous rat apocellular retinol-binding proteins expressed in Escherichia coli.

PubMed

Levin, M S; Locke, B; Yang, N C; Li, E; Gordon, J I

1988-11-25

Cellular retinol-binding protein (CRBP) and cellular retinol-binding protein II (CRBP II) are 132-residue cytosolic proteins which have 56% amino acid sequence identity and bind all-trans-retinol as their endogenous ligand. They belong to a family of cytoplasmic proteins which have evolved to bind distinct hydrophobic ligands. Their patterns of tissue-specific and developmental regulation are distinct. We have compared the ligand binding properties of rat apo-CRBP and apo-CRBP II that have been expressed in Escherichia coli. Several observations indicate that the E. coli-derived apoproteins are structurally similar to the native rat proteins: they co-migrate on isoelectric focusing gels; and when complexed with all-trans-retinol, their absorption and excitation/emission spectra are nearly identical to those of the authentic rat holoproteins. Comparative lifetime and acrylamide quenching studies suggest that there are differences in the conformations of apo-CRBP and apo-CRBP II. The interaction of E. coli-derived apo-CRBP and apo-CRBP II with a variety of retinoids was analyzed using spectroscopic techniques. Both apoproteins formed high affinity complexes with all-trans-retinol (K'd approximately 10 nM). In direct binding assays, all-trans-retinal bound to both apoproteins (K'd approximately 50 nM for CRBP; K'd approximately 90 nM for CRBP II). However, all-trans-retinal could displace all-trans-retinol bound to CRBP II but not to CRBP. These observations suggests that there is a specific yet distinct interaction between these two proteins and all-trans-retinal. Apo-CRBP and apo-CRBP II did not demonstrate significant binding to either retinoic acid or methyl retinoate, an uncharged derivative of all-trans-retinoic acid. This indicates that the carboxymethyl group of methyl retinoate cannot be sterically accommodated in their binding pockets and that failure to bind retinoic acid probably is not simply due to the negative charge of its C-15 carboxylate group. Finally, neither all-trans-retinol nor retinoic acid bound to E. coli-derived rat intestinal fatty acid-binding protein, a homologous protein whose tertiary structure is known. Together, the data suggest that these three family members have acquired unique functional capabilities.

Adsorption of amino acids by fullerenes and fullerene nanowhiskers

NASA Astrophysics Data System (ADS)

Hashizume, Hideo; Hirata, Chika; Fujii, Kazuko; Miyazawa, Kun'ichi

2015-12-01

We have investigated the adsorption of some amino acids and an oligopeptide by fullerene (C60) and fullerene nanowhiskers (FNWs). C60 and FNWs hardly adsorbed amino acids. Most of the amino acids used have a hydrophobic side chain. Ala and Val, with an alkyl chain, were not adsorbed by the C60 or FNWs. Trp, Phe and Pro, with a cyclic structure, were not adsorbed by them either. The aromatic group of C60 did not interact with the side chain. The carboxyl or amino group, with the frame structure of an amino acid, has a positive or negative charge in solution. It is likely that the C60 and FNWs would not prefer the charged carboxyl or amino group. Tri-Ala was adsorbed slightly by the C60 and FNWs. The carboxyl or amino group is not close to the center of the methyl group of Tri-Ala. One of the methyl groups in Tri-Ala would interact with the aromatic structure of the C60 and FNWs. We compared our results with the theoretical interaction of 20 bio-amino acids with C60. The theoretical simulations showed the bonding distance between C60 and an amino acid and the dissociation energy. The dissociation energy was shown to increase in the order, Val < Phe < Pro < Asp < Ala < Trp < Tyr < Arg < Leu. However, the simulation was not consistent with our experimental results. The adsorption of albumin (a protein) by C60 showed the effect on the side chains of Try and Trp. The structure of albumin was changed a little by C60. In our study Try and Tyr were hardly adsorbed by C60 and FNWs. These amino acids did not show a different adsorption behavior compared with other amino acids. The adsorptive behavior of mono-amino acids might be different from that of polypeptides.

Formation of amino acids by cobalt-60 irradiation of hydrogen cyanide solutions

NASA Technical Reports Server (NTRS)

Sweeney, M. A.; Toste, A. P.; Ponnamperuma, C.

1976-01-01

Experiments were conducted to study the pathway for the prebiotic origin of amino acids from hydrogen cyanide (HCN) under the action of ionizing radiation considered as an effective source of energy on the primitive earth. The irradiations were performed in a cobalt-60 source with a dose rate of 200,000 rad/hr. Seven naturally occurring amino acids are identified among the products formed by the hydrolysis of gamma-irradiated solutions of HCN: glycine, alanine, valine, serine, threonine, aspartic acid, and glutamic acid. The identity of these amino acids is established by gas chromatography and mass spectrometry. Control experiments provided evidence that the amino acids are not the result of contamination.

Straightforward synthesis of non-natural L-chalcogen and L-diselenide N-Boc-protected-γ-amino acid derivatives.

PubMed

Kawasoko, Cristiane Y; Foletto, Patricia; Rodrigues, Oscar E D; Dornelles, Luciano; Schwab, Ricardo S; Braga, Antonio L

2013-08-21

The synthesis of new chiral seleno-, telluro-, and thio-N-Boc-γ-amino acids is described herein. These new compounds were prepared through a simple and short synthetic route, from the inexpensive and commercially-available amino acid L-glutamic acid. The products, with a highly modular character, were obtained in good to excellent yields, via hydrolysis of chalcogen pyroglutamic derivatives with overall retention of the L-glutamic acid stereochemistry. Also, an L-diselenide-N-Boc-γ-amino acid was prepared in good yield. This new synthetic route represents an efficient method for preparing new L-chalcogen- and L-diselenide-γ-amino acids with biological potential.

Mirrors in the PDB: left-handed alpha-turns guide design with D-amino acids.

PubMed

Annavarapu, Srinivas; Nanda, Vikas

2009-09-22

Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Propensities for amino acids to occur in contiguous alpha(L) helices correlate with published thermodynamic scales for incorporation of D-amino acids into alpha(R) helices. Two backbone rules for terminating a left-handed helix are found: an alpha(R) conformation is disfavored at the amino terminus, and a beta(R) conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to alpha(L) helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. By examining left-handed alpha-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed alpha-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds.

Mirrors in the PDB: left-handed α-turns guide design with D-amino acids

PubMed Central

Annavarapu, Srinivas; Nanda, Vikas

2009-01-01

Background Incorporating variable amino acid stereochemistry in molecular design has the potential to improve existing protein stability and create new topologies inaccessible to homochiral molecules. The Protein Data Bank has been a reliable, rich source of information on molecular interactions and their role in protein stability and structure. D-amino acids rarely occur naturally, making it difficult to infer general rules for how they would be tolerated in proteins through an analysis of existing protein structures. However, protein elements containing short left-handed turns and helices turn out to contain useful information. Molecular mechanisms used in proteins to stabilize left-handed elements by L-amino acids are structurally enantiomeric to potential synthetic strategies for stabilizing right-handed elements with D-amino acids. Results Propensities for amino acids to occur in contiguous αL helices correlate with published thermodynamic scales for incorporation of D-amino acids into αR helices. Two backbone rules for terminating a left-handed helix are found: an αR conformation is disfavored at the amino terminus, and a βR conformation is disfavored at the carboxy terminus. Helix capping sidechain-backbone interactions are found which are unique to αL helices including an elevated propensity for L-Asn, and L-Thr at the amino terminus and L-Gln, L-Thr and L-Ser at the carboxy terminus. Conclusion By examining left-handed α-turns containing L-amino acids, new interaction motifs for incorporating D-amino acids into right-handed α-helices are identified. These will provide a basis for de novo design of novel heterochiral protein folds. PMID:19772623

Study of Nanocomposites of Amino Acids and Organic Polyethers by Means of Mass Spectrometry and Molecular Dynamics Simulation

NASA Astrophysics Data System (ADS)

Zobnina, V. G.; Kosevich, M. V.; Chagovets, V. V.; Boryak, O. A.

A problem of elucidation of structure of nanomaterials based on combination of proteins and polyether polymers is addressed on the monomeric level of single amino acids and oligomers of PEG-400 and OEG-5 polyethers. Efficiency of application of combined approach involving experimental electrospray mass spectrometry and computer modeling by molecular dynamics simulation is demonstrated. It is shown that oligomers of polyethers form stable complexes with amino acids valine, proline, histidine, glutamic, and aspartic acids. Molecular dynamics simulation has shown that stabilization of amino acid-polyether complexes is achieved due to winding of the polymeric chain around charged groups of amino acids. Structural motives revealed for complexes of single amino acids with polyethers can be realized in structures of protein-polyether nanoparticles currently designed for drug delivery.

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 . ...

Hydration of amino acids: FTIR spectra and molecular dynamics studies.

PubMed

Panuszko, Aneta; Adamczak, Beata; Czub, Jacek; Gojło, Emilia; Stangret, Janusz

2015-11-01

The hydration of selected amino acids, alanine, glycine, proline, valine, isoleucine and phenylalanine, has been studied in aqueous solutions by means of FTIR spectra of HDO isotopically diluted in H2O. The difference spectra procedure and the chemometric method have been applied to remove the contribution of bulk water and thus to separate the spectra of solute-affected HDO. To support interpretation of obtained spectral results, molecular dynamics simulations of amino acids were performed. The structural-energetic characteristic of these solute-affected water molecules shows that, on average, water affected by amino acids forms stronger and shorter H-bonds than those in pure water. Differences in the influence of amino acids on water structure have been noticed. The effect of the hydrophobic side chain of an amino acid on the solvent interactions seems to be enhanced because of the specific cooperative coupling of water strong H-bond chain, connecting the carboxyl and amino groups, with the clathrate-like H-bond network surrounding the hydrocarbon side chain. The parameter derived from the spectral data, which corresponds to the contributions of the population of weak hydrogen bonds of water molecules which have been substituted by the stronger ones in the hydration sphere of amino acids, correlated well with the amino acid hydrophobicity indexes.

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

PubMed

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

2017-02-24

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

Specificity of neutral amino acid uptake at the basolateral side of the epithelium in the cat salivary gland in situ.

PubMed

Bustamante, J C; Mann, G E; Yudilevich, D L

1981-01-01

1. Amino acid uptake was measured in resting cat submandibular glands with either a natural blood supply or perfused at constant flow with a Krebs-albumin solution. Following a bolus arterial injection of a 3H-labelled amino acid and D-[14C]mannitol (extracellular reference tracer), the venous effluent was immediately sampled sequentially. The maximal uptake, Umax, from the blood or perfusate was determined from the paired-tracer dilution curves using the expression: uptake % = (1 -- (3H/14C) X 100). 2. In glands with a natural blood supply, Umax values up to 46% were measured for short-chain (serine and alanine) and long-chain (valine, methionine, leucine, isoleucine, 1-amino-cyclopentane cyclopentane carboxylic acid, phenylalanine, tryptophan, tyrosine, histidine and glutamine) neutral amino acids. In contrast, Umax was negligible for amino acids of the imino-glycine group (proline and glycine) and the nonmetabolized amino acids, 2-aminoisobutyric acid (AIB) and methylaminoisobutyric acid (MeAIB). 3. In glands with a natural blood supply addition of an unlabelled amino acid to the tracer injectate reduced Umax for the test acid by up to 80%. The pattern of these interactions suggested the presence of two transport systems for neutral amino acids, one preferring short-chain and the other long-chain amino acids. 4. In glands perfused at constant flow rates with an amino acid-free Krebs-albumin solution high Umax values were measured: L-serine (66%), L-alanine (54%), L-leucine (43%), L-phenylalanine (42%) and L-tyrosine (51%). Only a low uptake was observed for L-proline (8%) and glycine (14%). There was no uptake of methylaminoisobutyric acid which confirms the result obtained in glands with an intact circulation. 5. Saturation of L-phenylalanine influx was observed in perfused glands as the perfusate concentration of unlabelled L-phenylalanine was increased from 0.5 to 20 mmol . 1-1. A Michaelis--Menten analysis based on a single entry system indicated an apparent Km of 6.4 +/- 0.8 mmol . 1-1 and a Vmax of 1719 +/- 94 nmol . min-1g.-1 6. Since the fenestrated capillaries in the salivary gland are readily permeable to the test amino acid and D-mannitol, it is most probable that the amino acid carriers are located in the basolateral side of the epithelium. 7. The use of a paired-tracer dilution technique to measure uptake in a single circulatory passage has enabled a detailed characterization of neutral amino acid transport in the salivary gland and has overcome the limitation of previous studies based on solute transfer from blood to saliva.

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.

Effects of ω-Amino Acids and Related Compounds on Staphylococcal Infections in Mice: a Combined Prophylactic-Therapeutic Procedure 1

PubMed Central

Tsuchiya, Yoshiki; Tanaka, Kinji; Cook, Elton S.; Nutini, Leo G.

1970-01-01

By a short-term combined prophylactic-therapeutic procedure, the following compounds were found to be active against staphylococcal infections in Swiss mice: γ-aminobutyric acid, γ-amino-β-hydroxybutyric acid (GABOB), δ-amino-valeric acid (DAVA), ε-aminocaproic acid (EACA), trans-4-aminomethylcyclohexanecarboxylic acid (trans-AMCHA), taurine, and cysteic acid. Many of these compounds had displayed limited or no activity by a previously used prophylactic procedure. Although DAVA and GABOB were the most potent of the straight-chain ω-amino acids, trans-AMCHA displayed the greatest antistaphylococcic activity of the ω-amino acids thus far investigated. Homocarnosine (γ-aminobutyrl histidine, which also was active by the prophylactic procedure) equalled trans-AMCHA in activity. Taurine was similar in potency to DAVA, and the activity of cysteic acid approximated that of EACA. PMID:5422309

Interactions of zinc octacarboxyphthalocyanine with selected amino acids and with albumin

NASA Astrophysics Data System (ADS)

Kliber, Marta; Broda, Małgorzata A.; Nackiewicz, Joanna

2016-02-01

Effect of selected amino acids (glycine, L-histidine, L-cysteine, L-serine, L-tryptophan) and albumin on the spectroscopic properties and photostability of zinc octacarboxyphthalocyanine (ZnPcOC) was explored in the phosphate buffer at a pH of 7.0. The photodegradation of ZnPcOC alone and in the presence of amino acids or albumin has been investigated in aqueous phase using UV-366 nm and daylight irradiation. Kinetic analysis showed that the interaction with amino acids or albumin enhances the photostability of ZnPcOC. To answer the question of how zinc phthalocyanine interacts with amino acids extensive DFT calculations were performed. Analysis of the optimized geometry features of ZnPcOC: amino acids complexes in the gas phase and in water environment as well as the BSSE corrected interaction energies indicates that the more likely is the formation of equatorial complexes in which H-bonds are formed between the COOH groups of the phthalocyanine and carboxyl or amino groups of amino acids. UV-Vis spectra calculated by employing time dependent density functional theory (TD-DFT) are also consistent with this conclusion.

The amino-terminal hydrophilic region of the vacuolar transporter Avt3p is dispensable for the vacuolar amino acid compartmentalization of Schizosaccharomyces pombe.

PubMed

Kawano-Kawada, Miyuki; Chardwiriyapreecha, Soracom; Manabe, Kunio; Sekito, Takayuki; Akiyama, Koichi; Takegawa, Kaoru; Kakinuma, Yoshimi

2016-12-01

Avt3p, a vacuolar amino acid exporter (656 amino acid residues) that is important for vacuolar amino acid compartmentalization as well as spore formation in Schizosaccharomyces pombe, has an extremely long hydrophilic region (approximately 290 amino acid residues) at its N-terminus. Because known functional domains have not been found in this region, its functional role was examined with a deletion mutant avt3 (∆1-270) expressed in S. pombe avt3∆ cells. The deletion of this region did not affect its intracellular localization or vacuolar contents of basic amino acids as well as neutral ones. The defect of avt3Δ cells in spore formation was rescued by the expression of avt3 + but was not completely rescued by the expression of avt3 (∆1-270) . The N-terminal region is thus dispensable for the function of Avt3p as an amino acid exporter, but it is likely to be involved in the role of Avt3p under nutritional starvation conditions.

Investigation and kinetic evaluation of the reactions of hydroxymethylfurfural with amino and thiol groups of amino acids.

PubMed

Hamzalıoğlu, Aytül; Gökmen, Vural

2018-02-01

In this study, reactions of hydroxymethylfurfural (HMF) with selected amino acids (arginine, cysteine and lysine) were investigated in HMF-amino acid (high moisture) and Coffee-amino acid (low moisture) model systems at 5, 25 and 50°C. The results revealed that HMF reacted efficiently and effectively with amino acids in both high and low moisture model systems. High-resolution mass spectrometry (HRMS) analyses of the reaction mixtures confirmed the formations of Michael adduct and Schiff base of HMF with amino acids. Calculated pseudo-first order reaction rate constants were in the following order; k Cysteine >k Arginine >k Lysine for high moisture model systems. Comparing to these rate constants, the k Cysteine decreased whereas, k Arginine and k Lysine increased under the low moisture conditions of Coffee-amino acid model systems. The temperature dependence of the rate constants was found to obey the Arrhenius law in a temperature range of 5-50°C under both low and high moisture conditions. Copyright © 2017 Elsevier Ltd. All rights reserved.

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

PubMed Central

2005-01-01

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

Enantioselective micellar electrokinetic chromatography of dl-amino acids using (+)-1-(9-fluorenyl)-ethyl chloroformate derivatization and UV-induced fluorescence detection.

PubMed

Prior, Amir; van de Nieuwenhuijzen, Erik; de Jong, Gerhardus J; Somsen, Govert W

2018-05-22

Chiral analysis of dl-amino acids was achieved by micellar electrokinetic chromatography coupled with UV-excited fluorescence detection. The fluorescent reagent (+)-1-(9-fluorenyl)ethyl chloroformate was employed as chiral amino acid derivatizing agent and sodium dodecyl sulfate served as pseudo-stationary phase for separating the formed amino acid diastereomers. Sensitive analysis of (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids was achieved applying a xenon-mercury lamp for ultraviolet excitation, and a spectrograph and charge-coupled device for wavelength-resolved emission detection. Applying signal integration over a 30-nm emission wavelength interval, signal-to-noise ratios for derivatized amino acids were up to 23 times higher as obtained using a standard photomultiplier for detection. The background electrolyte composition (electrolyte, pH, sodium dodecyl sulfate concentration, and organic solvent) was studied in order to attain optimal chemo- and enantioseparation. Enantioseparation of twelve proteinogenic dl-amino acids was achieved with chiral resolutions between 1.2 and 7.9, and detection limits for most derivatized amino acids in the 13-60 nM range (injected concentration). Linearity (coefficients of determination > 0.985) and peak-area and migration-time repeatabilities (relative standard deviations lower than 2.6 and 1.9%, respectively) were satisfactory. The employed fluorescence detection system provided up to 100-times better signal-to-noise ratios for (+)-1-(9-fluorenyl)ethyl chloroformate-amino acids than ultraviolet absorbance detection, showing good potential for d-amino acid analysis. This article is protected by copyright. All rights reserved. This article is protected by copyright. All rights reserved.

Identification of a novel amino acid racemase from a hyperthermophilic archaeon Pyrococcus horikoshii OT-3 induced by D-amino acids.

PubMed

Kawakami, Ryushi; Ohmori, Taketo; Sakuraba, Haruhiko; Ohshima, Toshihisa

2015-08-01

To date, there have been few reports analyzing the amino acid requirement for growth of hyperthermophilic archaea. We here found that the hyperthermophilic archaeon Pyrococcus horikoshii OT-3 requires Thr, Leu, Val, Phe, Tyr, Trp, His and Arg in the medium for growth, and shows slow growth in medium lacking Met or Ile. This largely corresponds to the presence, or absence, of genes related to amino acid biosynthesis in its genome, though there are exceptions. The amino acid requirements were dramatically lost by addition of D-isomers of Met, Leu, Val, allo-Ile, Phe, Tyr, Trp and Arg. Tracer analysis using (14)C-labeled D-Trp showed that D-Trp in the medium was used as a protein component in the cells, suggesting the presence of D-amino acid metabolic enzymes. Pyridoxal 5'-phosphate (PLP)-dependent racemase activity toward Met, Leu and Phe was detected in crude extract of P. horikoshii and was enhanced in cells grown in the medium supplemented with D-amino acids, especially D-allo-Ile. The gene encoding the racemase was narrowed down to one open reading frame on the basis of enzyme purification from P. horikoshii cells, and the recombinant enzyme exhibited PLP-dependent racemase activity toward several amino acids, including Met, Leu and Phe, but not Pro, Asp or Glu. This is the first report showing the presence in a hyperthermophilic archaeon of a PLP-dependent amino acid racemase with broad substrate specificity that is likely responsible for utilization of D-amino acids for growth.

Quantum Computational Calculations of the Ionization Energies of Acidic and Basic Amino Acids: Aspartate, Glutamate, Arginine, Lysine, and Histidine

NASA Astrophysics Data System (ADS)

de Guzman, C. P.; Andrianarijaona, M.; Lee, Y. S.; Andrianarijaona, V.

An extensive knowledge of the ionization energies of amino acids can provide vital information on protein sequencing, structure, and function. Acidic and basic amino acids are unique because they have three ionizable groups: the C-terminus, the N-terminus, and the side chain. The effects of multiple ionizable groups can be seen in how Aspartate's ionizable side chain heavily influences its preferred conformation (J Phys Chem A. 2011 April 7; 115(13): 2900-2912). Theoretical and experimental data on the ionization energies of many of these molecules is sparse. Considering each atom of the amino acid as a potential departing site for the electron gives insight on how the three ionizable groups affect the ionization process of the molecule and the dynamic coupling between the vibrational modes. In the following study, we optimized the structure of each acidic and basic amino acid then exported the three dimensional coordinates of the amino acids. We used ORCA to calculate single point energies for a region near the optimized coordinates and systematically went through the x, y, and z coordinates of each atom in the neutral and ionized forms of the amino acid. With the calculations, we were able to graph energy potential curves to better understand the quantum dynamic properties of the amino acids. The authors thank Pacific Union College Student Association for providing funds.

Enhancement of selectivity and resolution in the enantioseparation of uncharged compounds using mixtures of oppositely charged cyclodextrins in capillary electrophoresis.

PubMed

Abushoffa, Adel M; Fillet, Marianne; Servais, Anne-Catherine; Hubert, Philippe; Crommen, Jacques

2003-01-01

The enantiomeric separation of some nonsteroidal anti-inflammatory drugs (NSAIDs) was investigated in capillary electrophoresis (CE) using dual systems with mixtures of charged cyclodextrin (CD) derivatives. A significant enhancement of selectivity and resolution could be achieved in the enantioseparation of these analytes in their uncharged form by the simultaneous addition of two oppositely charged CD derivatives to the background electrolyte. The combination of the single-isomer cationic CD, permethyl-6-monoamino-6-monodeoxy-beta-CD (PMMAbetaCD) and the single-isomer polyanionic CD, heptakis-6-sulfato-beta-cyclodextrin (HSbetaCD) in a pH 2.5 phosphoric acid-triethanolamine buffer, was designed and employed for the enantioseparation of profens. The improvement in selectivity and resolution can be attributed to the fact that the two CDs, which lead to independent and enantioselective complexation with the analyte enantiomers, have not only opposite effects on the electrophoretic mobility of these compounds but also opposite affinity patterns towards the enantiomers of these compounds. Binding constants for these enantiomers with each CD were determined using linear regression approach, in order to be able to predict the effect of the concentrations of the two CDs on enantiomeric selectivity and resolution in such dual systems.

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.

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

Murakami, Taro, E-mail: tamuraka@sgk.ac.jp; Yoshinaga, Mariko

Highlights: •Regulation of amino acid transporter expression in working muscle remains unclear. •Expression of amino acid transporters for leucine were induced by a bout of exercise. •Requirement of leucine in muscle cells might regulate expression of its transporters. •This information is beneficial for understanding the muscle remodeling by exercise. -- Abstract: We here investigated whether an acute bout of endurance exercise would induce the expression of amino acid transporters that regulate leucine transport across plasma and lysosomal membranes in rat skeletal muscle. Rats ran on a motor-driven treadmill at a speed of 28 m/min for 90 min. Immediately after themore » exercise, we observed that expression of mRNAs encoding L-type amino acid transporter 1 (LAT1) and CD98 was induced in the gastrocnemius, soleus, and extensor digitorum longus (EDL) muscles. Sodium-coupled neutral amino acid transporter 2 (SNAT2) mRNA was also induced by the exercise in those three muscles. Expression of proton-assisted amino acid transporter 1 (PAT1) mRNA was slightly but not significantly induced by a single bout of exercise in soleus and EDL muscles. Exercise-induced mRNA expression of these amino acid transporters appeared to be attenuated by repeated bouts of the exercise. These results suggested that the expression of amino acid transporters for leucine may be induced in response to an increase in the requirement for this amino acid in the cells of working skeletal muscles.« less

Characterization of d-succinylase from Cupriavidus sp. P4-10-C and its application in d-amino acid synthesis.

PubMed

Sumida, Yosuke; Iwai, Sachio; Nishiya, Yoshiaki; Kumagai, Shinya; Yamada, Toshihide; Azuma, Masayuki

2018-03-01

d-Amino acids are important building blocks for various compounds, such as pharmaceuticals and agrochemicals. A more cost-effective enzymatic method for d-amino acid production is needed in the industry. We improved a one-pot enzymatic method for d-amino acid production by the dynamic kinetic resolution of N-succinyl amino acids using two enzymes: d-succinylase (DSA) from Cupriavidus sp. P4-10-C, which hydrolyzes N-succinyl-d-amino acids enantioselectively to their corresponding d-amino acid, and N-succinyl amino acid racemase (NSAR, EC.4.2.1.113) from Geobacillus stearothermophilus NCA1503. In this study, DSA and NSAR were purified and their properties were investigated. The optimum temperature of DSA was 50°C and it was stable up to 55°C. The optimum pH of DSA and NSAR was around 7.5. In d-phenylalanine production, the optical purity of product was improved to 91.6% ee from the examination about enzyme concentration. Moreover, 100 mM N-succinyl-dl-tryptophan was converted to d-tryptophan at 81.8% yield with 94.7% ee. This enzymatic method could be useful for the industrial production of various d-amino acids. Copyright © 2017 The Society for Biotechnology, Japan. Published by Elsevier B.V. All rights reserved.

Determination of Selected Amino Acids in Serum of Patients with Liver Disease.

PubMed

Kanďár, Roman; Drábková, Petra; Toiflová, Tereza; Čegan, Alexander

2016-01-01

The determination of amino acids can be a reliable approach for extended diagnosis of liver diseases. This is because liver disease can be a cause of impaired amino acid metabolism. Therefore, a method for the determination of serum amino acids, applicable for clinical purposes, is necessary. The aim of this study was to find differences in the levels of selected amino acids between patients with liver disease and a control group. Samples of peripheral venous blood were obtained from a group of patients with liver disease (n = 131, 59 women at an average age of 60 years and 72 men at an average age of 52 years) and a control group (n = 105, 47 women at an average age of 62 years and 58 men at an average age of 58 years). Before the separation, the amino acids were derivatized with naphthalene-2,3-dicarboxaldehyde. For the separation, reverse phase column was used. The effluent was monitored with a fluorescence detector. There were significant differences in the concentrations of some amino acids between the patients and the control group, but also between women and men. Correlations between some amino acids and markers of liver blood tests and lipid metabolism were observed. A simple, relatively rapid and selective HPLC method with fluorescence detection for the determination of selected amino acids in serum has been developed.

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

USDA-ARS?s Scientific Manuscript database

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 s...

Amino acid analyses of Apollo 14 samples.

NASA Technical Reports Server (NTRS)

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

1972-01-01

Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

Growth and clinical variables in nitrogen-restricted piglets fed an adjusted essential amino acid mix: Effects using free amino acid-based diets

USDA-ARS?s Scientific Manuscript database

Excess protein intake in early life has been linked to obesity and metabolic syndrome in later life. Yet, protein, and in particular the essential amino acids (EAA), need to be present in adequate quantity to support growth. Using a piglet model restricted in dietary amino acids (AA), our objective...

Decarboxylative Arylation of α-Amino Acids via Photoredox Catalysis: A One-Step Conversion of Biomass to Drug Pharmacophore

PubMed Central

2015-01-01

The direct decarboxylative arylation of α-amino acids has been achieved via visible light-mediated photoredox catalysis. This method offers rapid entry to prevalent benzylic amine architectures from an abundant biomass, specifically α-amino acid precursors. Significant substrate scope is observed with respect to both the amino acid and arene components. PMID:24712922

Effects of DDT and BHC on amino acid content and its varieties in Chlorella vulgaris Beij. and Cladophora sp.

NASA Astrophysics Data System (ADS)

Lin, Yixiong

1991-03-01

In Chlorella vulgaris Beij. and Cladophora sp. treated with different concentrations of r-BHC and p, p-DDT, the protein and free amino acid content in both were higher than those in the controls, and the free amino acid content was even higher than the protein amino acid content.

Stable isotope fingerprinting: a novel method for identifying plant, fungal, or bacterial origins of amino acids

Treesearch

Thomas Larsen; D. Lee Taylor; Mary Beth Leigh; Diane M. O' Brien

2009-01-01

Amino acids play an important role in ecology as essential nutrients for animals and as currencies in symbiotic associations. Here we present a new approach to tracing the origins of amino acids by identifying unique patterns of carbon isotope signatures generated by amino acid synthesis in plants, fungi, and bacteria ("13C fingerprints...

Mapping N-linked glycosylation of carbohydrate-active enzymes in the secretome of Aspergillus nidulans grown on lignocellulose.

PubMed

Rubio, Marcelo Ventura; Zubieta, Mariane Paludetti; Franco Cairo, João Paulo Lourenço; Calzado, Felipe; Paes Leme, Adriana Franco; Squina, Fabio Marcio; Prade, Rolf Alexander; de Lima Damásio, André Ricardo

2016-01-01

The genus Aspergillus includes microorganisms that naturally degrade lignocellulosic biomass, secreting large amounts of carbohydrate-active enzymes (CAZymes) that characterize their saprophyte lifestyle. Aspergillus has the capacity to perform post-translational modifications (PTM), which provides an additional advantage for the use of these organisms as a host for the production of heterologous proteins. In this study, the N-linked glycosylation of CAZymes identified in the secretome of Aspergillus nidulans grown on lignocellulose was mapped. Aspergillus nidulans was grown in glucose, xylan and pretreated sugarcane bagasse (SCB) for 96 h, after which glycoproteomics and glycomics were carried out on the extracellular proteins (secretome). A total of 265 proteins were identified, with 153, 210 and 182 proteins in the glucose, xylan and SCB substrates, respectively. CAZymes corresponded to more than 50 % of the total secretome in xylan and SCB. A total of 182 N-glycosylation sites were identified, of which 121 were detected in 67 CAZymes. A prevalence of the N-glyc sequon N-X-T (72.2 %) was observed in N-glyc sites compared with N-X-S (27.8 %). The amino acids flanking the validated N-glyc sites were mainly composed of hydrophobic and polar uncharged amino acids. Selected proteins were evaluated for conservation of the N-glyc sites in Aspergilli homologous proteins, but a pattern of conservation was not observed. A global analysis of N-glycans released from the proteins secreted by A. nidulans was also performed. While the proportion of N-glycans with Hex5 to Hex9 was similar in the xylan condition, a prevalence of Hex5 was observed in the SCB and glucose conditions. The most common and frequent N-glycosylated motifs, an overview of the N-glycosylation of the CAZymes and the number of mannoses found in N-glycans were analyzed. There are many bottlenecks in protein production by filamentous fungi, such as folding, transport by vesicles and secretion, but N-glycosylation in the correct context is a fundamental event for defining the high levels of secretion of target proteins. A comprehensive analysis of the protein glycosylation processes in A. nidulans will assist with a better understanding of glycoprotein structures, profiles, activities and functions. This knowledge can help in the optimization of heterologous expression and protein secretion in the fungal host.

Genetic variation in food choice behaviour of amino acid-deprived Drosophila.

PubMed

Toshima, Naoko; Hara, Chieko; Scholz, Claus-Jürgen; Tanimura, Teiichi

2014-10-01

To understand homeostatic regulation in insects, we need to understand the mechanisms by which they respond to external stimuli to maintain the internal milieu. Our previous study showed that Drosophila melanogaster exhibit specific amino acid preferences. Here, we used the D.melanogaster Genetic Reference Panel (DGRP), which is comprised of multiple inbred lines derived from a natural population, to examine how amino acid preference changes depending on the internal nutritional state in different lines. We performed a two-choice preference test and observed genetic variations in the response to amino acid deprivation. For example, a high-responding line showed an enhanced preference for amino acids even after only 1day of deprivation and responded to a fairly low concentration of amino acids. Conversely, a low-responding line showed no increased preference for amino acids after deprivation. We compared the gene expression profiles between selected high- and the low-responding lines and performed SNP analyses. We found several groups of genes putatively involved in altering amino acid preference. These results will contribute to future studies designed to explore how the genetic architecture of an organism evolves to adapt to different nutritional environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Free amino acids as phagostimulants in cricket nuptial gifts: support for the ‘Candymaker’ hypothesis

PubMed Central

Warwick, Stuart; Vahed, Karim; Raubenheimer, David; Simpson, Stephen J.

2009-01-01

Nuptial gifts that are manufactured by the male are found in numerous insect species and some spiders, but there have been very few studies of the composition of such gifts. If, as has been proposed recently, nuptial gifts represent sensory traps, males will be selected to produce gifts that are attractive to females but such gifts will not necessarily provide the female with nutritional benefits (the ‘Candymaker’ hypothesis). We examined the free amino acid content of the spermatophylax of the cricket Gryllodes sigillatus (Orthoptera: Gryllidae) using high performance liquid chromatography (HPLC). The spermatophylax (dry weight) consisted of approximately 7 per cent free amino acids. The free amino acid composition was highly imbalanced, with a low proportion of essential amino acids (18.7%) and a high proportion of proline and glycine. The main free amino acids found in the spermatophylax appeared to act as phagostimulants: the duration of feeding on artificial gels by females was positively related to the free amino acid content of the gels. The results therefore suggest that males use free amino acids to ‘sweeten’ a relatively low-value food item. A possible function of glycine in inhibiting female movement is also proposed. PMID:19158029

A Molecular and Cellular Context-Dependent Role for Ir76b in Detection of Amino Acid Taste.

PubMed

Ganguly, Anindya; Pang, Lisa; Duong, Vi-Khoi; Lee, Angelina; Schoniger, Hanni; Varady, Erika; Dahanukar, Anupama

2017-01-17

Amino acid taste is expected to be a universal property among animals. Although sweet, bitter, salt, and water tastes have been well characterized in insects, the mechanisms underlying amino acid taste remain elusive. From a Drosophila RNAi screen, we identify an ionotropic receptor, Ir76b, as necessary for yeast preference. Using calcium imaging, we identify Ir76b + amino acid taste neurons in legs, overlapping partially with sweet neurons but not those that sense other tastants. Ir76b mutants have reduced responses to amino acids, which are rescued by transgenic expression of Ir76b and a mosquito ortholog AgIr76b. Co-expression of Ir20a with Ir76b is sufficient for conferring amino acid responses in sweet-taste neurons. Notably, Ir20a also serves to block salt response of Ir76b. Our study establishes the role of a highly conserved receptor in amino acid taste and suggests a mechanism for mutually exclusive roles of Ir76b in salt- and amino-acid-sensing neurons. Copyright © 2017 The Author(s). Published by Elsevier Inc. All rights reserved.

Amino acids and hydrocarbons approximately 3,800-Myr old in the Isua rocks, southwestern Greenland

NASA Technical Reports Server (NTRS)

Nagy, B.; Engel, M. H.; Zumberge, J. E.; Ogino, H.; Chang, S. Y.

1981-01-01

Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, which contains the oldest known rocks on earth, are discussed. Similarities are pointed out between the relative amino acid abundances of the Isua rocks and those of lichens found on their surfaces, and a lack of substantial racemization indicated by the low D/L ratios in the 3800-million year old rock samples is noted. Experimental results showing the possibility of amino acid diffusion from lichens into the rocks are presented. Comparisons of the Isua rock amino acid D/L ratios with those reported for samples from other regions indicates that none of the Isua amino acids are older than a few tens of thousands to a few hundred thousand years. Analyses of the saturated hydrocarbons of the Isua samples reveals no odd carbon number preference, which may indicate antiquity, however laboratory experiments have shown that amino acids and aromatic and saturated aliphatic hydrocarbons could not have survived the metamorphic history of the Isua rocks. The evidence presented thus suggests that the amino acids and hydrocarbons found are not of the age of the sediments.

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.

Mutual Exclusion of Urea and Trimethylamine N-oxide from Amino Acids in Mixed Solvent Environment

NASA Astrophysics Data System (ADS)

Ganguly, Pritam; Hajari, Timir; Shea, Joan-Emma; van der Vegt, Nico F. A.

2015-03-01

We study the solvation thermodynamics of individual amino acids in mixed urea and trimethylamine N-oxide (TMAO) solutions using molecular dynamics simulations and the Kirkwood-Buff theory. Our results on the preferential interactions between the amino acids and the cosolvents (urea and TMAO) show a mutual exclusion of both the cosolvents from the amino acid surface in the mixed cosolvent condition which is followed by an increase in the cosolvent-cosolvent aggregation away from the amino acid surface. The effects of the mixed cosolvents on the association of the amino acids and the preferential solvation of the amino acids by water are found to be highly non-linear in terms of the effects of the individual cosolvents. A similar result has been found for the association of the protein backbone, mimicked by triglycine. Our results have been confirmed by different TMAO force-fields and the mutual exclusions of the cosolvents from the amino acids are found to be independent of the choice of the strength of the TMAO-water interactions. Based on our data, a general mechanism can potentially be proposed for the effects of the mixed cosolvents on the preferential solvations of the solutes including the case of cononsolvency.

Amino Acid Catabolism in Alzheimer's Disease Brain: Friend or Foe?

PubMed Central

2017-01-01

There is a dire need to discover new targets for Alzheimer's disease (AD) drug development. Decreased neuronal glucose metabolism that occurs in AD brain could play a central role in disease progression. Little is known about the compensatory neuronal changes that occur to attempt to maintain energy homeostasis. In this review using the PubMed literature database, we summarize evidence that amino acid oxidation can temporarily compensate for the decreased glucose metabolism, but eventually altered amino acid and amino acid catabolite levels likely lead to toxicities contributing to AD progression. Because amino acids are involved in so many cellular metabolic and signaling pathways, the effects of altered amino acid metabolism in AD brain are far-reaching. Possible pathological results from changes in the levels of several important amino acids are discussed. Urea cycle function may be induced in endothelial cells of AD patient brains, possibly to remove excess ammonia produced from increased amino acid catabolism. Studying AD from a metabolic perspective provides new insights into AD pathogenesis and may lead to the discovery of dietary metabolite supplements that can partially compensate for alterations of enzymatic function to delay AD or alleviate some of the suffering caused by the disease. PMID:28261376

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

PubMed

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

2018-01-01

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

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

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

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

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

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

DOE PAGES

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

2018-01-11

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

Free amino acids as phagostimulants in cricket nuptial gifts: support for the 'Candymaker' hypothesis.

PubMed

Warwick, Stuart; Vahed, Karim; Raubenheimer, David; Simpson, Stephen J

2009-04-23

Nuptial gifts that are manufactured by the male are found in numerous insect species and some spiders, but there have been very few studies of the composition of such gifts. If, as has been proposed recently, nuptial gifts represent sensory traps, males will be selected to produce gifts that are attractive to females but such gifts will not necessarily provide the female with nutritional benefits (the 'Candymaker' hypothesis). We examined the free amino acid content of the spermatophylax of the cricket Gryllodes sigillatus (Orthoptera: Gryllidae) using high performance liquid chromatography (HPLC). The spermatophylax (dry weight) consisted of approximately 7 per cent free amino acids. The free amino acid composition was highly imbalanced, with a low proportion of essential amino acids (18.7%) and a high proportion of proline and glycine. The main free amino acids found in the spermatophylax appeared to act as phagostimulants: the duration of feeding on artificial gels by females was positively related to the free amino acid content of the gels. The results therefore suggest that males use free amino acids to 'sweeten' a relatively low-value food item. A possible function of glycine in inhibiting female movement is also proposed.

Fortifying Horticultural Crops with Essential Amino Acids: A Review.

PubMed

Wang, Guoping; Xu, Mengyun; Wang, Wenyi; Galili, Gad

2017-06-19

To feed the world's growing population, increasing the yield of crops is not the only important factor, improving crop quality is also important, and it presents a significant challenge. Among the important crops, horticultural crops (particularly fruits and vegetables) provide numerous health compounds, such as vitamins, antioxidants, and amino acids. Essential amino acids are those that cannot be produced by the organism and, therefore, must be obtained from diet, particularly from meat, eggs, and milk, as well as a variety of plants. Extensive efforts have been devoted to increasing the levels of essential amino acids in plants. Yet, these efforts have been met with very little success due to the limited genetic resources for plant breeding and because high essential amino acid content is generally accompanied by limited plant growth. With a deep understanding of the biosynthetic pathways of essential amino acids and their interactions with the regulatory networks in plants, it should be possible to use genetic engineering to improve the essential amino acid content of horticultural plants, rendering these plants more nutritionally favorable crops. In the present report, we describe the recent advances in the enhancement of essential amino acids in horticultural plants and possible future directions towards their bio-fortification.

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

PubMed

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

2018-01-30

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

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

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

PubMed Central

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

2018-01-01

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

Products of the Strecker Synthesis as Indicators of Parent Body Conditions of the Murchison Meteorite

NASA Technical Reports Server (NTRS)

Lerner, Narcinda R.; Cooper, George W.; Chang, Sherwood (Technical Monitor)

1996-01-01

The Strecker synthesis, R2C=O + HCN + NH3 yields R2C(NH2)CN + H2O yields R2C(NH2)CO2H has been proposed as a source of amino acids in meteorites. The detection of carbonlyl compounds, the precursors of the amino acids in the Strecker synthesis, and a-hydroxy acids, important by-products of the Strecker synthesis, in the Murchison meteorite supports this conjecture. However, the following observations raise questions about the Strecker synthesis as the source of a-amino and a-hydroxy acids in Murchison: a) Imino acetic acids are also important by-products of the Strecker synthesis and have not been reported in Murchison. b) a-aminisobutyric acid (AIBA) is one of the most abundant amino acids in Murchison but the Strecker synthesis conducted at room temperature produced only small amounts of AIBA relative to other amino acids. c) If the a-amino and a-hydroxy acids observed in Murchison arose from a common precursor this ought to be reflected in their relative abundances, but the straight chain a-hydroxy acids appeared to be relatively abundant compared with the analogous a-amino acids. In order to address question a) we have examined a non-hydrolyzed aqueous extract of the Murchison meteorite. Imino di acetic acid, Imino propionic acetic acid and Imino butyric acetic acid (both isomers) have been identified in this fraction. The relative abundances of amino acids and imino acetic acids in this fraction are consistent with a Strecker synthesis at low temperature (263 K) as a origin of both the amino acids and the imino acetic acids found on Murchison. To deal with questions b) and c) we have carried out laboratory simulations of the Strecker synthesis. The starting concentrations for carbonlyl compounds used were based on estimates of what these concentrations might have been on the parent body. for the carbonyl compounds this estimate was determined by the amount of carbonyl compound found on Murchison plus the amounts of the corresponding amino acid and hydroxy acid found on Murchison and the rock to water ratio estimated by Clayton and Mayeda (1984). The cyanide concentration was that estimated by Peltzer et al. (1984). The ammonia concentration and pH were varied. We studied these mixtures at 298 K and 263 K. We found that high relative abundances of AIBA were produced at 263 K but not at 298 K. We only produced a-methyl a-amino hydroxy acids at 263 K with no initial ammonia. The abundances of a-amino acids, a-hydroxy acids and imino acids found on Murchison are consistent with a Strecker synthesis which took place at low temperature and with a low concentration of ammonia.

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.

Installing amino acids and peptides on N-heterocycles under visible-light assistance

PubMed Central

Jin, Yunhe; Jiang, Min; Wang, Hui; Fu, Hua

2016-01-01

Readily available natural α-amino acids are one of nature’s most attractive and versatile building blocks in synthesis of natural products and biomolecules. Peptides and N-heterocycles exhibit various biological and pharmaceutical functions. Conjugation of amino acids or peptides with N-heterocycles provides boundless potentiality for screening and discovery of diverse biologically active molecules. However, it is a great challenge to install amino acids or peptides on N-heterocycles through formation of carbon-carbon bonds under mild conditions. In this article, eighteen N-protected α-amino acids and three peptides were well assembled on phenanthridine derivatives via couplings of N-protected α-amino acid and peptide active esters with substituted 2-isocyanobiphenyls at room temperature under visible-light assistance. Furthermore, N-Boc-proline residue was successfully conjugated with oxindole derivatives using similar procedures. The simple protocol, mild reaction conditions, fast reaction, and high efficiency of this method make it an important strategy for synthesis of diverse molecules containing amino acid and peptide fragments. PMID:26830014

A vacuolar membrane protein Avt7p is involved in transport of amino acid and spore formation in Saccharomyces cerevisiae.

PubMed

Tone, Junichi; Yamanaka, Atsushi; Manabe, Kunio; Murao, Nami; Kawano-Kawada, Miyuki; Sekito, Takayuki; Kakinuma, Yoshimi

2015-01-01

Active transport systems for various amino acids operate in the vacuolar membrane of Saccharomyces cerevisiae. The gene families for vacuolar amino acid transporters were identified by reverse genetics experiments. In the AVT transporter family, Avt1p works for active uptake of amino acid into vacuole, and Avt3p, Avt4p, and Avt6p for active extrusion of amino acid from vacuole to cytosol. Here, we found green fluorescent protein-tagged Avt7p, an unidentified member of the AVT family, localized to the vacuolar membrane of S. cerevisiae. Disruption of the AVT7 gene enhanced both vacuolar contents of several amino acids and uptake activities of glutamine and proline by vacuolar membrane vesicles. Efficiency of spore formation was impaired by the disruption of the AVT7 gene, suggesting the physiological importance of Avt7p-dependent efflux of amino acid from vacuoles under nutrient-poor condition.

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

PubMed

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

2016-07-15

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

The 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.

Concentrations of amino acids in the plasma of neonatal foals with septicemia.

PubMed

Zicker, S C; Spensley, M S; Rogers, Q R; Willits, N H

1991-07-01

Concentrations of amino acids in the plasma of 13 neonatal foals with septicemia were compared with the concentrations of amino acids in the plasma of 13 age-matched neonatal foals without septicemia. Analysis of the results revealed significantly lower concentrations of arginine, citrulline, isoleucine, proline, threonine, and valine in the plasma of foals with septicemia. The ratio of the plasma concentrations of the branched chain amino acids (isoleucine, leucine, and valine) to the aromatic amino acids (phenylalanine and tyrosine), was also significantly lower in the foals with septicemia. In addition, the concentrations of alanine, glycine, and phenylalanine were significantly higher in the plasma of foals with septicemia. Therefore, neonatal foals with septicemia had significant differences in the concentrations of several amino acids in their plasma, compared with concentrations from healthy foals. These differences were compatible with protein calorie inadequacy and may be related to an alteration in the intake, production, use, or clearance of amino acids from the plasma pool in sepsis.

Amino acids as indicators to elucidate organic matter degradation profile in the Cochin estuarine sediments, Southwest coast of India.

PubMed

Salas, P M; Sujatha, C H; Ratheesh Kumar, C S; Cheriyan, Eldhose

2018-02-01

Surface sediments from three zones (fresh water, estuarine, and riverine/industrial zones) of the Cochin estuary, Southwest coast of India, were seasonally analyzed to understand the nature and degradation status of organic matter. Amino acid-based indices such as total hydrolyzable amino acids (THAAs), percentage contributions of amino acid carbon to total organic carbon (THAA-C%) and those of amino acid nitrogen to total nitrogen (THAA-N%), and degradation index (DI) were calculated. Elevated levels of amino acids in the sediments of the estuary were attributed to river runoff, autochthonous production, allochthonous inputs, and industrial and domestic effluent discharges. Higher levels of THAA-C%, THAA-N%, THAA, and positive DI found in most of the stations suggest the fresh deposition of organic matter. Multivariate statistical analyses revealed that the dispersal pattern of amino acids depends on the sediment texture, organic matter, redox state, and microbial processes in the study region. Copyright © 2017 Elsevier Ltd. All rights reserved.

Efficient optical resolution of amino acid by alanine racemaze chiral analogue supported on mesoporous carbon

NASA Astrophysics Data System (ADS)

Jang, D.; Kim, K.; Park, D.; Kim, G.

2012-09-01

Optically pure D-amino acids are industrially important chiral building blocks for the synthesis of pharmaceuticals, food ingredients, and drug intermediates. Chemoenzymatic dynamic kinetic-resolution processes have recently been developed for deracemization of amino acids. S-ARCA would be a good candidate for the selective adsorption of D amino acid through the imine formation reaction. The organic phase containing S-ARCA adsorbent, TPPC or Ionic Liquid (as a phase transfer catalyst) in MC were coated on the surfaces of mesoporous carbon C-SBA-15(CMK). The aqueous solution of racemic D/L-amino acid and NaOH were added to the carbon support coated with ARCA. The D/L ratios on ARCA and in solution were determined with increasing reaction time. S-ARCA has a unique property for the selective adsorption of D- amino acid (up to 90% selcetivity) in the racemic mixture. The fixed bed reactor containing ARCA/carbon support was also adopted successfully for the selective separation of amino acid.

Influence of the yeast strain on the changes of the amino acids, peptides and proteins during sparkling wine production by the traditional method.

PubMed

Martínez-Rodríguez, A J; Carrascosa, A V; Martín-Alvarez, P J; Moreno-Arribas, V; Polo, M C

2002-12-01

The influence of five yeast strains on the nitrogen fractions, amino acids, peptides and proteins, during 12 months of aging of sparkling wines produced by the traditional or Champenoise method, was studied. High-performance liquid chromatography (HPLC) techniques were used for analysis of the amino acid and peptide fractions. Proteins plus polypeptides were determined by the colorimetric Bradford method. Four main stages were detected in the aging of wines with yeast. In the first stage, a second fermentation took place; amino acids and proteins plus polypeptides diminished, and peptides were liberated. In the second stage, there was a release of amino acids and proteins, and peptides were degraded. In the third stage, the release of proteins and peptides predominated. In the fourth stage, the amino acid concentration diminished. The yeast strain used influenced the content of free amino acids and peptides and the aging time in all the nitrogen fractions.

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 (TTD).

The retention and recovery of amino acids from pork longissimus muscle following cooking to either 60°C or 75°C.

PubMed

Wilkinson, B H P; Lee, E; Purchas, R W; Morel, P C H

2014-01-01

Samples of pork longissimus muscle (n=16) cooked to either 60°C or 75°C in a water bath for 90 min were assessed for amino acid composition. Recovery of protein in the cooked meat plus the cooking juice was >93% and was slightly higher at 60°C (P=0.031), but retention in the meat was only 89% and 82% for the lower and higher temperatures (P<0.0001). Individual amino acids varied in recovery and retention with retention being particularly low for taurine and histidine. The balance of indispensable amino acids was less than ideal, with leucine and valine being the limiting amino acids by about 30% for both raw and cooked pork. Cooking had no detrimental effect on amino acid balance. Some examples of small effects of genotype and sex on amino acid composition of pork were shown. © 2013.

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).

Protein Solubility, Digestibility and Fractionation after Germination of Sorghum Varieties

PubMed Central

Afify, Abd El-Moneim M. R.; El-Beltagi, Hossam S.; Abd El-Salam, Samiha M.; Omran, Azza A.

2012-01-01

The changes in crude protein, free amino acids, amino acid composition, protein solubility, protein fractionation and protein digestibility after germination of sorghum were investigated. Sorghum varieties (Dorado, Shandaweel-6, Giza-15) were soaked for 20 h followed by germination for 72 h; the results revealed that crude protein and free amino acids in raw sorghum varieties ranged from 10.62 to 12.46% and 0.66 to 1.03 mg/g, respectively. Shandaweel-6 was the highest variety in crude protein and free amino acids content. After germination, crude protein was decreased and free amino acids were increased. There was an increase in content of valine and phenylalanine amino acids after germination. On the other hand, there was a decrease in most of amino acids after germination. After germination protein solubility was significantly increased. Regarding protein fractions, there was an increase in albumin, globulin and kafirin proteins and a decrease in cross linked kafirin and cross linked glutelin after germination. PMID:22319611

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

PubMed

Rush, J D; Bielski, B H

1995-06-01

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

Patterns of free amino acids in German convenience food products: marked mismatch between label information and composition.

PubMed

Hermanussen, M; Gonder, U; Jakobs, C; Stegemann, D; Hoffmann, G

2010-01-01

Free amino acids affect food palatability. As information on amino acids in frequently purchased pre-packaged food is virtually absent, we analyzed free amino acid patterns of 17 frequently purchased ready-to-serve convenience food products, and compared them with the information obtained from the respective food labels. Quantitative amino acid analysis was performed using ion-exchange chromatography. gamma-Aminobutyric acid (GABA) concentrations were verified using a stable isotope dilution gas chromatography/mass spectrometry (GC-MS) method. The patterns of free amino acids were compared with information obtained from food labels. An obvious mismatch between free amino acid patterns and food label information was detected. Even on considering that tomatoes and cereal proteins are naturally rich in glutamate, the concentrations of free glutamate outranged the natural concentration of this amino acid in several products, and strongly suggested artificial enrichment. Free glutamate was found to be elevated even in dishes that explicitly state 'no glutamate added'. Arginine was markedly elevated in lentils. Free cysteine was generally low, possibly reflecting thermal destruction of this amino acid during food processing. The meat and brain-specific dipeptide carnosine (CARN) was present in most meat-containing products. Some products did not contain detectable amounts of CARN in spite of meat content being claimed on the food labels. We detected GABA at concentrations that contribute significantly to the taste sensation. This investigation highlights a marked mismatch between food label information and food composition.

Determination of the D and L isomers of some protein amino acids present in soils

NASA Technical Reports Server (NTRS)

Pollock, G. E.; Cheng, C.-N.; Cronin, S. E.

1977-01-01

The D and L isomers of some protein amino acids present in soils were measured by using a gas chromatographic technique. The results of two processing procedures were compared to determine the better method. Results of the comparison indicated that the determination of D and L percentages requires amino acid purification if one is to obtain accurate data. It was found that very significant amounts of D-alanine, D-aspartic acid, and D-glutamic acid were present in the contemporary soils studied. Valine, isoleucine, leucine, proline, and phenylalanine generally contained only a trace to very small amounts of the D isomer. It is probable that the D-amino acids from the alanine, aspartic, and glutamic acids are contributed to the soil primarily via microorganisms. The finding of very significant quantities of some D-amino acids (about 5-16%) in present-day soils may alert some investigators of geological sediments to a possible problem in using amino acid racemization as an age-dating technique.

Preparation of tritium-labeled optical isomers of amino acids by ligand exchange chromatography on polyacrylamide sorbent containing L-phenylalanine groupings

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

Zolotarev, Yu.A.; Penkina, V.I.; Dostavalov, I.N.

Tritium-labeled optically active amino acids are obtained by resolving racemates of the corresponding amino acids by chromatography on a chiral polyacrylamide sorbent, filled with copper ions. The chiral sorbent is obtained by the action of formaldehyde and L-phenylalanine on a Biogel P-4 polyacrylamide gel in an alkaline medium. Data are given on the ligand exchange chromatography of amino acids on this sorbent, depending on the degree of filling of the sorbent by copper ions and the concentration of the eluent. Conditions were selected for the quantitative resolution of racemates of amino acids and examples are given of a preparative obtainingmore » of tritium labeled optical isomers of amino acids.« less

Phenylalanine ab initio models for the simulation of skin natural moisturizing factor

NASA Astrophysics Data System (ADS)

Carvalho, B. G.; Raniero, L. J.; Martin, A. A.; Favero, P. P.

2013-04-01

In this study, we evaluated models that can be used to simulate amino acids in biological environments via density functional theory (DFT). The goal was to obtain realistic representations that combine computational economy and result quality when compared to experimental data. We increased the complexity of the models by using a model of an amino acid in a vacuum, followed by a water-solvated amino acid model. To consider pH variation, we simulated zwitterionic and nonionic amino acid configurations. The amino acid chosen for testing was phenylalanine, an aromatic amino acid present in high concentrations in the natural moisturizing factor of skin that plays a fundamental role in ultraviolet protection and vitiligo disease. To validate the models, vibrational modes and electronic properties were calculated and compared to experimental results.

Supernovae, neutrinos and the chirality of amino acids.

PubMed

Boyd, Richard N; Kajino, Toshitaka; Onaka, Takashi

2011-01-01

A mechanism for creating an enantioenrichment in the amino acids, the building blocks of the proteins, that involves global selection of one handedness by interactions between the amino acids and neutrinos from core-collapse supernovae is defined. The chiral selection involves the dependence of the interaction cross sections on the orientations of the spins of the neutrinos and the (14)N nuclei in the amino acids, or in precursor molecules, which in turn couple to the molecular chirality. It also requires an asymmetric distribution of neutrinos emitted from the supernova. The subsequent chemical evolution and galactic mixing would ultimately populate the Galaxy with the selected species. The resulting amino acids could either be the source thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's proteinaceous amino acids.

Detection of diastereomer peptides as the intermediates generating D-amino acids during acid hydrolysis of peptides.

PubMed

Miyamoto, Tetsuya; Sekine, Masae; Ogawa, Tetsuhiro; Hidaka, Makoto; Watanabe, Hidenori; Homma, Hiroshi; Masaki, Haruhiko

2016-11-01

In this study, we investigated whether the amino acid residues within peptides were isomerized (and the peptides converted to diastereomers) during the early stages of acid hydrolysis. We demonstrate that the model dipeptides L-Ala-L-Phe and L-Phe-L-Ala are epimerized to produce the corresponding diastereomers at a very early stage, prior to their acid hydrolytic cleavage to amino acids. Furthermore, the sequence-inverted dipeptides were generated via formation of a diketopiperazine during hydrolytic incubation, and these dipeptides were also epimerized. The proportion of diastereomers increased rapidly during incubation for 0.5-2 h. During acid hydrolysis, C-terminal residues of the model dipeptides were isomerized faster than N-terminal residues, consistent with the observation that the D-amino acid values of the C-terminal residues determined by the 0 h-extrapolating method were larger than those of the N-terminal residues. Thus, the artificial D-amino acid contents determined by the 0 h-extrapolating method appear to be products of the isomerization of amino acid residues during acid hydrolysis.

Toxicological deteriorations of two volatile oils of Matricaria chamomilla and Clerodendron inerme on the adult house fly Musca domestica L.

PubMed

Shoukry, I F

1997-12-01

The adult stage of the house fly Musca domestica L. was treated topically with the sublethal doses of LD25, LD50 and LD75 of chamomile, Matricaria chamomilla L. flowers and jasmine, Clerodendron inerme G. leaves oils. Various biological activities of adult stage as well as the amino acids of the treated adults ovaries were determined. Amino acids determinations were achieved on newly emerged flies and on the three and four days old flies. The LD50s. of 76 and 84 ug/fly of the two oils were used for Matricaria chamomilla and Clerodendron inerme oil, respectively. Treatment with the two volatile oils induced serious effects on the biology and biotic potential of Musca domestica. Treatment was significantly increased the acidic and the aromatic amino acids during oogenesis. In contrast the quantity of aliphatic amino acids was significantly decreased while the hydroxy amino acids have inconsistent results. The hydroxy amino acids were remarkably increased in the ovaries during three days of development, and then decreased in the fourth day. Moreover, the concentration of basic and the sulfur amino acids were varied with the two treatments and the amino acid was completely disappeared in the ovaries of the treated flies.

A simple and specific procedure to permeabilize the plasma membrane of Schizosaccharomyces pombe.

PubMed

Chardwiriyapreecha, Soracom; Hondo, Kana; Inada, Hiroko; Chahomchuen, Thippayarat; Sekito, Takayuki; Iwaki, Tomoko; Kakinuma, Yoshimi

2009-09-01

Cu(2+)-treatment is a useful technique in selectively permeabilizing the fungal plasma membrane. We describe herein a practical application with Schizosaccharomyces pombe. Incubation of cells with 0.5 mM CuCl(2) at 30 degrees C for 20 min induced efficient leakage of cytosolic constituents. The kinetic characteristics of the calcium and amino acid flux from Cu(2+)-treated S. pombe cells suggested that the Cu(2+) treatment permeabilized the plasma membrane without loss of vacuolar function. As a further application of the method, the amino acid contents of Cu(2+)-treated and untreated cells were also determined. The amino acid pool of Cu(2+)-treated wild-type cells was enriched in basic amino acids but not in acidic amino acids, as is characteristic of the vacuolar amino acid pool of fungi, including Saccharomyces cerevisiae and Neurosporra crassa. The amino acid pool of the S. pombe V-ATPase mutant vma1Delta was also successfully determined. We conclude that the vacuolar amino acid pool of S. pombe can be measured using Cu(2+)-treated cells. The method is simple, inexpensive, and rapid relative to the isolation of vacuolar vesicles, making it useful in estimating vacuolar pools and transport across the vacuolar membrane.

40 CFR 180.473 - Glufosinate ammonium; tolerances for residues.

Code of Federal Regulations, 2010 CFR

2010-07-01

... residues of the herbicide glufosinate-ammonium (butanoic acid, 2-amino-4-(hydroxymethylphosphinyl...-propionic acid, expressed as 2-amino-4-(hydroxymethylphosphinyl)butanoic acid equivalents, in or on the... herbicide glufosinate ammonium, butanoic acid, 2-amino-4-(hydroxymethylphosphinyl)-, monoammonium salt and...

Analysis of Chiral Carboxylic Acids in Meteorites

NASA Technical Reports Server (NTRS)

Burton, A. S.; Elsila, J. E.; Hein, J. E.; Aponte, J. C.; Parker, E. T.; Glavin, D. P.; Dworkin, J. P.

2015-01-01

Homochirality of amino acids in proteins and sugars in DNA and RNA is a critical feature of life on Earth. In the absence of a chiral driving force, however, reactions leading to the synthesis of amino acids and sugars result in racemic mixtures. It is currently unknown whether homochirality was necessary for the origins of life or if it was a product of early life. The observation of enantiomeric excesses of certain amino acids of extraterrestrial origins in meteorites provides evidence to support the hypothesis that there was a mechanism for the preferential synthesis or destruction of a particular amino acid enantiomer [e.g., 1-3]. The cause of the observed chiral excesses is un-clear, although at least in the case of the amino acid isovaline, the degree of aqueous alteration that occurred on the meteorite parent body is correlated to the isovaline L-enantiomeric excess [3, 4]. This suggests that chiral symmetry is broken and/or amplified within the meteorite parent bodies. Besides amino acids, there have been only a few reports of other meteoritic compounds found in enantiomeric excess: sugars and sugar acids [5, 6] and the hydroxy acid lactic acid [7]. Determining whether or not additional types of molecules in meteorites are also present in enantiomeric excesses of extraterrestrial information will provide insights into mechanisms for breaking chiral symmetry. Though the previous measurements (e.g., enantiomeric composition of lactic acid [7], and chiral carboxylic acids [8]) were made by gas chromatography-mass spectrometry, the potential for increased sensitivity of liquid chromatography-mass spectrometry (LC-MS) analyses is important because for many meteorite samples, only small sample masses are available for study. Furthermore, at least in the case of amino acids, many of the largest amino acid enantiomeric excesses were observed in samples that contained lower abundances (tens of ppb) of a given amino acid enantiomer. In the present work, we describe our efforts to develop highly sensitive LC-MS methods for the analysis of chiral carboxylic acids including hydroxy acids.

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

NASA Technical Reports Server (NTRS)

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

1989-01-01

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

Laser spectroscopy and dynamics of crystal lattices of chirally pure and racemic phases of amino acids

NASA Astrophysics Data System (ADS)

Belyanchikov, M. A.; Gorelik, V. S.; Gorshunov, B. P.; Pyatyshev, A. Yu.

2017-03-01

Strong sharp lines due to the librational modes characterized by a pseudoscalar symmetry type have been found in the low-frequency Raman spectra of the lattices of glycine and tyrosine amino acids. The intensities of these lines exceed those for Raman scattering in the region of intramolecular vibrations. The spectra of chirally pure and racemic phases of amino acids differ significantly. The results obtained can be used to observe stimulated Raman scattering from the librational modes of crystalline amino acids and monitor the chiral purity of bioactive preparations containing amino acids.

The Production of Amino Acids in Interstellar Ices: Implications for Meteoritic Organics

NASA Technical Reports Server (NTRS)

Sandford, A.; Bernstein, M. P.; Dworkin, J. P.; Cooper, G. W.; Allamandola, L. J.; DeVincenzi, D. (Technical Monitor)

2002-01-01

Indigenous amino acids have been detected in a number of meteorites, over 70 in the Murchison meteorite alone. It has been generally accepted that the amino acids in meteorites formed in liquid water on an asteroid or comet parent-body. However, the water in the Murchison meteorite, for example, was depleted of deuterium, making the distribution of deuterium in organic acids in Murchison difficult to explain. Similarly, occasional but consistent meteoritic biases for non-terrestrial L amino acids cannot be reasonably rationalized by liquid water parent-body reactions. We will present the results of a laboratory demonstration showing that the amino acids glycine, alanine, and serine should result from the UV (ultraviolet) photolysis of interstellar ice grains. This suggests that some meteoritic amino acids may be the result of interstellar ice photochemistry, rather than having formed by reactions in liquid water. We will describe some of the potential implications of these findings for the organic materials found in primitive meteorites, in particular how interstellar ice synthesis might more easily accommodate the presence and distribution of deuterium, and the meteoritic bias for L amino acids.

Biochemical studies of some non-conventional sources of proteins. Part 7. Effect of detoxification treatments on the nutritional quality of apricot kernels.

PubMed

el-Adawy, T A; Rahma, E H; el-Badawey, A A; Gomaa, M A; Lásztity, R; Sarkadi, L

1994-01-01

Detoxification of apricot kernels by soaking in distilled water and ammonium hydroxide for 30 h at 47 degrees C decreased the total protein, non-protein nitrogen, total ash, glucose, sucrose, minerals, non-essential amino acids, polar amino acids, acidic amino acids, aromatic amino acids, antinutritional factors, hydrocyanic acid, tannins and phytic acid. On the other hand, removal of toxic and bitter compounds from apricot kernels increased the relative content of crude fibre, starch, total essential amino acids. Higher in-vitro protein digestibility and biological value was also observed. Generally, the detoxified apricot kernels were nutritionally well balanced. Utilization and incorporation of detoxified apricot kernel flours in food products is completely safe from the toxicity point of view.

Properties and substrate specificities of the phenylalanyl-transfer-ribonucleic acid synthetases of Aesculus species

PubMed Central

Anderson, J. W.; Fowden, L.

1970-01-01

1. Phenylalanyl-tRNA synthetases have been partially purified from cotyledons of seeds of Aesculus californica, which contains 2-amino-4-methylhex-4-enoic acid, and from four other species of Aesculus that do not contain this amino acid. The A. californica preparation was free from other aminoacyl-tRNA synthetases, and the contaminating synthetase activity in preparations from A. hippocastanum was decreased to acceptable limits by conducting assays of pyrophosphate exchange activity in 0.5m-potassium chloride. 2. The phenylalanyl-tRNA synthetase from each species activated 2-amino-4-methylhex-4-enoic acid with Km 30–40 times that for phenylalanine. The maximum velocity for 2-amino-4-methylhex-4-enoic acid was only 30% of that for phenylalanine with the A. californica enzyme, but the maximum velocities for the two substrates were identical for the other four species. 3. 2-Amino-4-methylhex-4-enoic acid was not found in the protein of A. californica, so discrimination against this amino acid probably occurs in the step of transfer to tRNA, though subcellular localization, or subsequent steps of protein synthesis could be involved. 4. Crotylglycine, methallylglycine, ethallylglycine, 2-aminohex-4,5-dienoic acid, 2-amino-5-methylhex-4-enoic acid, 2-amino-4-methylhex-4-enoic acid, β-(thien-2-yl)alanine, β-(pyrazol-1-yl)alanine, phenylserine and m-fluorophenylalanine were substrates for pyrophosphate exchange catalysed by the phenylalanyl-tRNA synthetases of A. californica or A. hippocastanum. Allylglycine, phenylglycine and 2-amino-4-phenylbutyric acid were inactive. PMID:5493504

Electron-induced electron yields of uncharged insulating materials

NASA Astrophysics Data System (ADS)

Hoffmann, Ryan Carl

Presented here are electron-induced electron yield measurements from high-resistivity, high-yield materials to support a model for the yield of uncharged insulators. These measurements are made using a low-fluence, pulsed electron beam and charge neutralization to minimize charge accumulation. They show charging induced changes in the total yield, as much as 75%, even for incident electron fluences of <3 fC/mm2, when compared to an uncharged yield. The evolution of the yield as charge accumulates in the material is described in terms of electron recapture, based on the extended Chung and Everhart model of the electron emission spectrum and the dual dynamic layer model for internal charge distribution. This model is used to explain charge-induced total yield modification measured in high-yield ceramics, and to provide a method for determining electron yield of uncharged, highly insulating, high-yield materials. A sequence of materials with progressively greater charge susceptibility is presented. This series starts with low-yield Kapton derivative called CP1, then considers a moderate-yield material, Kapton HN, and ends with a high-yield ceramic, polycrystalline aluminum oxide. Applicability of conductivity (both radiation induced conductivity (RIC) and dark current conductivity) to the yield is addressed. Relevance of these results to spacecraft charging is also discussed.

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.

Glutamate and aspartate are decreased in the skin in amyotrophic lateral sclerosis

NASA Technical Reports Server (NTRS)

Ono, S.; Yamauchi, M.

1992-01-01

We measured the levels of amino acids in biopsied skin from eight patients with amyotrophic lateral sclerosis (ALS) and seven controls. The most conspicuous changes in ALS patients were as follows. First, the contents of the acidic amino acids glutamate and aspartate were significantly decreased in ALS, and were negatively and significantly associated with the duration of illness. Second, the levels of the collagen-associated amino acids hydroxyproline, proline, glycine, alanine, and hydroxylysine were significantly decreased in ALS, and correlated inversely with the duration of illness. These results suggest that there are abnormalities of acidic amino acids and collagen-associated amino acids in the skin of patients with ALS. These changes may underlie the pathogenesis of ALS.

Quantitative structure-activity relationship study of antioxidative peptide by using different sets of amino acids descriptors

NASA Astrophysics Data System (ADS)

Li, Yao-Wang; Li, Bo; He, Jiguo; Qian, Ping

2011-07-01

A database consisting of 214 tripeptides which contain either His or Tyr residue was applied to study quantitative structure-activity relationships (QSAR) of antioxidative tripeptides. Partial Least-Squares Regression analysis (PLSR) was conducted using parameters individually of each amino acid descriptor, including Divided Physico-chemical Property Scores (DPPS), Hydrophobic, Electronic, Steric, and Hydrogen (HESH), Vectors of Hydrophobic, Steric, and Electronic properties (VHSE), Molecular Surface-Weighted Holistic Invariant Molecular (MS-WHIM), isotropic surface area-electronic charge index (ISA-ECI) and Z-scale, to describe antioxidative tripeptides as X-variables and antioxidant activities measured with ferric thiocyanate methods were as Y-variable. After elimination of outliers by Hotelling's T 2 method and residual analysis, six significant models were obtained describing the entire data set. According to cumulative squared multiple correlation coefficients ( R2), cumulative cross-validation coefficients ( Q2) and relative standard deviation for calibration set (RSD c), the qualities of models using DPPS, HESH, ISA-ECI, and VHSE descriptors are better ( R2 > 0.6, Q2 > 0.5, RSD c < 0.39) than that of models using MS-WHIM and Z-scale descriptors ( R2 < 0.6, Q2 < 0.5, RSD c > 0.44). Furthermore, the predictive ability of models using DPPS descriptor is best among the six descriptors systems (cumulative multiple correlation coefficient for predict set ( Rext2) > 0.7). It was concluded that the DPPS is better to describe the amino acid of antioxidative tripeptides. The results of DPPS descriptor reveal that the importance of the center amino acid and the N-terminal amino acid are far more than the importance of the C-terminal amino acid for antioxidative tripeptides. The hydrophobic (positively to activity) and electronic (negatively to activity) properties of the N-terminal amino acid are suggested to play the most important significance to activity, followed by the hydrogen bond (positively to activity) of the center amino acid. The N-terminal amino acid should be a high hydrophobic and low electronic amino acid (such as Ala, Gly, Val, and Leu); the center amino acid would be an amino acid that possesses high hydrogen bond property (such as base amino acid Arg, Lys, and His). The structural characteristics of antioxidative peptide be found in this paper may contribute to the further research of antioxidative mechanism.

Uptake of free amino acids by bacteria-free larvae of the sand dollar Dendraster excentricus.

PubMed

Davis, J P; Stephens, G C

1984-10-01

Larvae of Dendraster excentricus were produced by collecting gametes and carrying out fertilization under aseptic conditions. Since gametes are free of bacteria in the gonad, bacteria-free (axenic) suspensions of larvae result. Net rates of entry of 14 amino acids and the rate of production of ammonia were simultaneously determined by high-performance liquid chromatography. The net rates of uptake of neutral amino acids were an order of magnitude greater than rates for basic and acidic amino acids. Influx of 14C-labeled leucine, arginine, and glutamate accurately reflects the net entry rate of these substrates. Uptake of amino acids by axenic suspensions of larvae was compared with uptake by suspensions prepared without aseptic precautions. There was no significant difference in net uptake of the 14 amino acids or in the pattern of oxidation and assimilation of [14C]leucine during short-term experiments of 4-h duration or less.

Synthesis and evaluation of L-cystathionine as a standard for amino acid analysis.

PubMed

Amino, Yusuke; Suzuki, Yumiko

2017-01-01

L-Cystathionine is a key nonprotein amino acid related to metabolic conditions. The quantitative determination of L-cystathionine in physiological fluids by amino acid analysis is important for clinical diagnosis; however, certified reference material for L-cystathionine with satisfactory purity, content, and quantity has been unavailable until recently. Consequently, a practical and simple method for the preparation of L-cystathionine was examined, which involves thioalkylation of N-tert-butoxycarbonyl-L-cysteine tert-butyl ester, derived from L-cystine, with (2S)-2-(tert-butoxycarbonyl)amino-4-iodobutanoic acid tert-butyl ester, derived from L-aspartic acid, to obtain L-cystathionine with protecting groups, followed by single-step deprotection under mild conditions. This method produces L-cystathionine in high purity (99.4%) and having sufficient percentage content according to amino acid analysis, which could be used as a standard for the amino acid analysis of physiological fluids.

Enzymatic preparation of. cap alpha. - and. beta. -deuterated or tritiated amino acids with l-methionine. gamma. -lyase

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

Esaki, N.; Sawada, S.; Tanaka, H.

L-Methionine ..gamma..-lyase catalyzes the exchange of ..cap alpha..- and ..beta..-hydrogens of L-methionine and S-methyl-L-cysteine with deuterium or tritium of solvents. The rate of ..cap alpha..-hydrogen exchange with deuterium was about 40 times faster than that of the elimination reactions. The deuterium and tritium were exchanged also with the ..cap alpha..- and ..beta..-hydrogens of the straight-chain amino acids which do not undergo the elimination: L-alanine, L-..cap alpha..-aminobutyrate, L-norvaline, and L-norleucine. No exchange occurs for the D-isomers, acidic L-amino acids, basic L-amino acids, and branched-chain L-amino acids, although ..cap alpha..-hydrogen of glycine, L-trypotophan, and L-phenylalanine is exchanged slowly. These enzymatic hydrogen-exchange reactionsmore » facilitate specific labeling of the L-amino acids with deuterium and tritium.« less

Production of a new D-amino acid oxidase from the fungus Fusarium oxysporum.

PubMed

Gabler, M; Fischer, L

1999-08-01

The fungus Fusarium oxysporum produced a D-amino acid oxidase (EC 1. 4.3.3) in a medium containing glucose as the carbon and energy source and ammonium sulfate as the nitrogen source. The specific D-amino acid oxidase activity was increased up to 12.5-fold with various D-amino acids or their corresponding derivatives as inducers. The best inducers were D-alanine (2.7 microkat/g of dry biomass) and D-3-aminobutyric acid (2.6 microkat/g of dry biomass). The addition of zinc ions was necessary to permit the induction of peroxisomal D-amino acid oxidase. Bioreactor cultivations were performed on a 50-liter scale, yielding a volumetric D-amino acid oxidase activity of 17 microkat liter(-1) with D-alanine as an inducer. Under oxygen limitation, the volumetric activity was increased threefold to 54 microkat liter(-1) (3,240 U liter(-1)).

Investigation of Soman Adducts of Human Hemoglobin by Liquid Chromatography

DTIC Science & Technology

2004-04-01

acid standard, with fifteen primary amino acids , was used to evaluate and refine the chromatographic methods . An LC/MS/MS was used to analyze the non...several chromatographic conditions and stationary phases were used to create an LC/MS/MS method to directly analyze the amino acids , these studies...terminated because of a lack of resolution of the amino acid peaks. Also, initial attempts to develop an HPLC method to separate individual amino acids

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...

[Amino acid composition of the rat quadriceps femoris muscle after a flight on the Kosmos-936 biosatellite].

PubMed

Vlasova, T F; Miroshnikova, E B; Poliakov, V V; Murugova, T P

1982-01-01

The amino acid composition of the quadriceps muscle of rats flown onboard the biosatellite Cosmos-936 and exposed to the ground-based synchronous control experiment was studied. The weightless rats showed changes in the amino acid concentration in the quadriceps muscle. The centrifuged flight and synchronous rats displayed an accumulation of free amino acids in the above muscle.

37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

Code of Federal Regulations, 2011 CFR

2011-07-01

... and/or amino acid sequences as part of the application. 1.823 Section 1.823 Patents, Trademarks, and... Amino Acid Sequences § 1.823 Requirements for nucleotide and/or amino acid sequences as part of the... incorporation-by-reference of the Sequence Listing as required by § 1.52(e)(5). The presentation of the...

37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

Code of Federal Regulations, 2013 CFR

2013-07-01

... and/or amino acid sequences as part of the application. 1.823 Section 1.823 Patents, Trademarks, and... Amino Acid Sequences § 1.823 Requirements for nucleotide and/or amino acid sequences as part of the... incorporation-by-reference of the Sequence Listing as required by § 1.52(e)(5). The presentation of the...

37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

Code of Federal Regulations, 2012 CFR

2012-07-01

... and/or amino acid sequences as part of the application. 1.823 Section 1.823 Patents, Trademarks, and... Amino Acid Sequences § 1.823 Requirements for nucleotide and/or amino acid sequences as part of the... incorporation-by-reference of the Sequence Listing as required by § 1.52(e)(5). The presentation of the...

37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

Code of Federal Regulations, 2010 CFR

2010-07-01

... and/or amino acid sequences as part of the application. 1.823 Section 1.823 Patents, Trademarks, and... Amino Acid Sequences § 1.823 Requirements for nucleotide and/or amino acid sequences as part of the... incorporation-by-reference of the Sequence Listing as required by § 1.52(e)(5). The presentation of the...

37 CFR 1.823 - Requirements for nucleotide and/or amino acid sequences as part of the application.

Code of Federal Regulations, 2014 CFR

2014-07-01

... and/or amino acid sequences as part of the application. 1.823 Section 1.823 Patents, Trademarks, and... Amino Acid Sequences § 1.823 Requirements for nucleotide and/or amino acid sequences as part of the... incorporation-by-reference of the Sequence Listing as required by § 1.52(e)(5). The presentation of the...

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 glucagon. Hyperglucagonemia may depend on hepatic steatosis rather than type 2 diabetes.

Expression and regulation of the neutral amino acid transporter B0AT1 in rat small intestine

PubMed Central

Jando, Julia; Camargo, Simone M. R.; Herzog, Brigitte

2017-01-01

Absorption of neutral amino acids across the luminal membrane of intestinal enterocytes is mediated by the broad neutral amino acid transporter B0AT1 (SLC6A19). Its intestinal expression depends on co-expression of the membrane-anchored peptidase angiotensin converting enzyme 2 (ACE2) and is additionally enhanced by aminopeptidase N (CD13). We investigated in this study the expression of B0AT1 and its auxiliary peptidases as well as its transport function along the rat small intestine. Additionally, we tested its possible short- and long-term regulation by dietary proteins and amino acids. We showed by immunofluorescence that B0AT1, ACE2 and CD13 co-localize on the luminal membrane of small intestinal villi and by Western blotting that their protein expression increases in distal direction. Furthermore, we observed an elevated transport activity of the neutral amino acid L-isoleucine during the nocturnal active phase compared to the inactive one. Gastric emptying was delayed by intragastric application of an amino acid cocktail but we observed no acute dietary regulation of B0AT1 protein expression and L-isoleucine transport. Investigation of the chronic dietary regulation of B0AT1, ACE2 and CD13 by different diets revealed an increased B0AT1 protein expression under amino acid-supplemented diet in the proximal section but not in the distal one and for ACE2 protein expression a reverse localization of the effect. Dietary regulation for CD13 protein expression was not as distinct as for the two other proteins. Ring uptake experiments showed a tendency for increased L-isoleucine uptake under amino acid-supplemented diet and in vivo L-isoleucine absorption was more efficient under high protein and amino acid-supplemented diet. Additionally, plasma levels of branched-chain amino acids were elevated under high protein and amino acid diet. Taken together, our experiments did not reveal an acute amino acid-induced regulation of B0AT1 but revealed a chronic dietary adaptation mainly restricted to the proximal segment of the small intestine. PMID:28915252

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

PubMed

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

1947-02-28

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

Amino Acid Permeases and Virulence in Cryptococcus neoformans

PubMed Central

Takahashi, Juliana Possato Fernandes; Guerra, Juliana Mariotti; Santos, Dayane Cristina da Silva; Purisco, Sônia Ueda; Melhem, Márcia de Souza Carvalho; Fazioli, Raquel dos Anjos; Phanord, Clerlune; Sartorelli, Patrícia; Vallim, Marcelo A.

2016-01-01

Fungal opportunistic pathogens colonize various environments, from plants and wood to human and animal tissue. Regarding human pathogens, one great challenge during contrasting niche occupation is the adaptation to different conditions, such as temperature, osmolarity, salinity, pressure, oxidative stress and nutritional availability, which may constitute sources of stress that need to be tolerated and overcome. As an opportunistic pathogen, C. neoformans faces exactly these situations during the transition from the environment to the human host, encountering nutritional constraints. Our previous and current research on amino acid biosynthetic pathways indicates that amino acid permeases are regulated by the presence of the amino acids, nitrogen and temperature. Saccharomyces cerevisiae and Candida albicans have twenty-four and twenty-seven genes encoding amino acid permeases, respectively; conversely, they are scarce in number in Basidiomycetes (C. neoformans, Coprinopsis cinerea and Ustilago maydis), where nine to ten permease genes can be found depending on the species. In this study, we have demonstrated that two amino acid permeases are essential for virulence in C. neoformans. Our data showed that C. neoformans uses two global and redundant amino acid permeases, Aap4 and Aap5 to respond correctly to thermal and oxidative stress. Double deletion of these permeases causes growth arrest in C. neoformans at 37°C and in the presence of hydrogen peroxide. The inability to uptake amino acid at a higher temperature and under oxidative stress also led to virulence attenuation in vivo. Our data showed that thermosensitivity caused by the lack of permeases Aap4 and Aap5 can be remedied by alkaline conditions (higher pH) and salinity. Permeases Aap4 and Aap5 are also required during fluconazole stress and they are the target of the plant secondary metabolite eugenol, a potent antifungal inhibitor that targets amino acid permeases. In summary, our work unravels (i) interesting physiological property of C. neoformans regarding its amino acid uptake system; (ii) an important aspect of virulence, which is the need for amino acid permeases during thermal and oxidative stress resistance and, hence, host invasion and colonization; and (iii) provides a convenient prototype for antifungal development, which are the amino acid permeases Aap4/Aap5 and their inhibitor. PMID:27695080