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  1. Enantiomer-specific selection of amino acids.

    Science.gov (United States)

    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.

  2. Enantiomeric Selective Adsorption of Amino Acid by Polysaccharide Composite Materials

    OpenAIRE

    Duri, Simon; Tran, Chieu D.

    2014-01-01

    A composite containing cellulose (CEL) and chitosan (CS) synthesized by a simple and recyclable method by using butylmethylimmidazolium chloride, an ionic liquid, was found to exhibit remarkable enantiomeric selectivity toward adsorption of amino acids. 100%CS shows the highest adsorption capacity and enantiomeric selectivity. A racemic amino acid can be enantiomerically resolved by 100%CS in about 96–120 hrs. Interestingly, adsorption by 50:50 CEL:CS is more similar to that by 100%CS than to...

  3. Aromatic amino acids in high selectivity bismuth(III) recognition.

    Science.gov (United States)

    Ghatak, Sumanta Kumar; Dey, Debarati; Sen, Souvik; Sen, Kamalika

    2013-04-21

    The three aromatic amino acids, tyrosine, tryptophan and phenylalanine, play different physiological roles in life processes. Metal ions capable of binding these amino acids may aid in the reduction of effective concentration of these amino acids in any physiological system. Here we have studied the efficacy of some heavy metals for their complexation with these three amino acids. Bismuth has been found to bind selectively with these aromatic amino acids and this was confirmed using spectrofluorimetric, spectrophotometric and cyclic voltammetric studies. The series of heavy metals has been chosen because each of these metals remains associated with the others at very low concentration levels and Bi(III) is the least toxic amongst the other elements. So, selective recognition for Bi(III) would also mean no response for the other heavy elements if contaminants are present even at low concentration levels. The affinity towards these amino acids has been found to be in the order tryptophan phenylalanine amino acids have been calculated using Benesi-Hildebrand equations and the corresponding free energy change has also been calculated. The values of the association constants obtained from BH equations using absorbance values corroborate with the Stern-Volmer constants obtained from fluorimetric studies. The evidence for complexation is also supported by the results of cyclic voltammetry.

  4. Amino acids

    Science.gov (United States)

    ... amino acids are: histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan , and valine. Nonessential amino acids "Nonessential" means that our bodies produce an amino ...

  5. Chlorine dioxide reaction with selected amino acids in water

    International Nuclear Information System (INIS)

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO2 with selected amino acids as model compounds that can be present in natural waters. The reaction of tryptophane, histidine and tyrosine (10 ppm each) with ClO2 were studied at molar ratios ranging from 0.25 to 4 in the presence or absence of oxygen. It was found that in the absence of oxygen adding substoichiometric amounts of ClO2 creates products that are structurally similar to the starting amino acids. Through a series of cascade reactions the initial product distribution gradually evolves toward simple, small carbon chain products that are far from the starting amino acid. The reaction product distribution revealed that chlorine dioxide can attack the electron-rich aromatic moieties as well as the nitrogen atom lone electron pair. Our study is relevant to gain knowledge on the reaction mechanism of ClO2 with ubiquitous amino acids present in natural waters.

  6. Content of amino acids and minerals in selected sorts of legumes

    OpenAIRE

    Stanislav Kráčmar; Pavel Švec; Petra Vojtíšková

    2013-01-01

    The aim of this study was to determine amino acid composition and mineral content in selected legume samples. All analyses were carried out at the laboratory temperature of 21±2 °C in triplicate. Amino acid composition was determined using the automatic amino acid analyzer AAA 400 with post-column derivatization. To assess the nutritional value of protein, index of essential amino acids (EAAI) was calculated. Minerals were determined using the atomic absorption spectrometer AA 30. All resu...

  7. A comparative proteomic analysis of the simple amino acid repeat distributions in Plasmodia reveals lineage specific amino acid selection.

    Directory of Open Access Journals (Sweden)

    Andrew R Dalby

    Full Text Available BACKGROUND: Microsatellites have been used extensively in the field of comparative genomics. By studying microsatellites in coding regions we have a simple model of how genotypic changes undergo selection as they are directly expressed in the phenotype as altered proteins. The simplest of these tandem repeats in coding regions are the tri-nucleotide repeats which produce a repeat of a single amino acid when translated into proteins. Tri-nucleotide repeats are often disease associated, and are also known to be unstable to both expansion and contraction. This makes them sensitive markers for studying proteome evolution, in closely related species. RESULTS: The evolutionary history of the family of malarial causing parasites Plasmodia is complex because of the life-cycle of the organism, where it interacts with a number of different hosts and goes through a series of tissue specific stages. This study shows that the divergence between the primate and rodent malarial parasites has resulted in a lineage specific change in the simple amino acid repeat distribution that is correlated to A-T content. The paper also shows that this altered use of amino acids in SAARs is consistent with the repeat distributions being under selective pressure. CONCLUSIONS: The study shows that simple amino acid repeat distributions can be used to group related species and to examine their phylogenetic relationships. This study also shows that an outgroup species with a similar A-T content can be distinguished based only on the amino acid usage in repeats, and suggest that this might be a useful feature for proteome clustering. The lineage specific use of amino acids in repeat regions suggests that comparative studies of SAAR distributions between proteomes gives an insight into the mechanisms of expansion and the selective pressures acting on the organism.

  8. Chiral morphology of calcite through selective binding of amino acids

    Science.gov (United States)

    Orme, Christine

    2002-03-01

    Many living organisms contain biominerals and composites with finely tuned properties, reflecting a remarkable level of control over the nucleation, growth and shape of the constituent crystals. Peptides and proteins play an important role in achieving this control. Using in situ AFM we find that site-specific binding of amino acid residues to surface steps changes the step-edge free energies, giving rise to direction-specific binding energies unique to individual amino acid enantiomers and leading to chiral modifications that propagate from atomic length scales to macroscopic length scales. Molecular modeling studies support an energetic basis for the differences in binding. Our results emphasize that the mechanism under-lying crystal modification through organic molecules is best understood by considering both stereochemical recognition as well as the effects of binding on the interfacial energies of the growing crystal.

  9. A new highly selective metabotropic excitatory amino acid agonist: 2-amino-4-(3-hydroxy-5-methylisoxazol-4-yl)butyric acid

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Sløk, F A; Skjaerbaek, N;

    1996-01-01

    -methylisoxazol-4-yl)hexanoic acid (10), were tested as ligands for metabotropic excitatory amino acid receptors (mGlu1 alpha, mGlu2, mGlu4a, and mGlu6). Whereas AMAA (6) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propinoic acid (AMPA, 7) are potent and highly selective agonists at N...

  10. Mutation-selection models of coding sequence evolution with site-heterogeneous amino acid fitness profiles.

    Science.gov (United States)

    Rodrigue, Nicolas; Philippe, Hervé; Lartillot, Nicolas

    2010-03-01

    Modeling the interplay between mutation and selection at the molecular level is key to evolutionary studies. To this end, codon-based evolutionary models have been proposed as pertinent means of studying long-range evolutionary patterns and are widely used. However, these approaches have not yet consolidated results from amino acid level phylogenetic studies showing that selection acting on proteins displays strong site-specific effects, which translate into heterogeneous amino acid propensities across the columns of alignments; related codon-level studies have instead focused on either modeling a single selective context for all codon columns, or a separate selective context for each codon column, with the former strategy deemed too simplistic and the latter deemed overparameterized. Here, we integrate recent developments in nonparametric statistical approaches to propose a probabilistic model that accounts for the heterogeneity of amino acid fitness profiles across the coding positions of a gene. We apply the model to a dozen real protein-coding gene alignments and find it to produce biologically plausible inferences, for instance, as pertaining to site-specific amino acid constraints, as well as distributions of scaled selection coefficients. In their account of mutational features as well as the heterogeneous regimes of selection at the amino acid level, the modeling approaches studied here can form a backdrop for several extensions, accounting for other selective features, for variable population size, or for subtleties of mutational features, all with parameterizations couched within population-genetic theory. PMID:20176949

  11. Interactions of zinc octacarboxyphthalocyanine with selected amino acids and with albumin

    Science.gov (United States)

    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.

  12. Interactions of zinc octacarboxyphthalocyanine with selected amino acids and with albumin.

    Science.gov (United States)

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

    2016-02-15

    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-366nm 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.

  13. Amino acid selective unlabeling for sequence specific resonance assignments in proteins

    Energy Technology Data Exchange (ETDEWEB)

    Krishnarjuna, B.; Jaipuria, Garima; Thakur, Anushikha [Indian Institute of Science, NMR Research Centre (India); D' Silva, Patrick, E-mail: patrick@biochem.iisc.ernet.in [Indian Institute of Science, Department of Biochemistry (India); Atreya, Hanudatta S., E-mail: hsatreya@sif.iisc.ernet.in [Indian Institute of Science, NMR Research Centre (India)

    2011-01-15

    Sequence specific resonance assignment constitutes an important step towards high-resolution structure determination of proteins by NMR and is aided by selective identification and assignment of amino acid types. The traditional approach to selective labeling yields only the chemical shifts of the particular amino acid being selected and does not help in establishing a link between adjacent residues along the polypeptide chain, which is important for sequential assignments. An alternative approach is the method of amino acid selective 'unlabeling' or reverse labeling, which involves selective unlabeling of specific amino acid types against a uniformly {sup 13}C/{sup 15}N labeled background. Based on this method, we present a novel approach for sequential assignments in proteins. The method involves a new NMR experiment named, {l_brace}{sup 12}CO{sub i}-{sup 15}N{sub i+1}{r_brace}-filtered HSQC, which aids in linking the {sup 1}H{sup N}/{sup 15}N resonances of the selectively unlabeled residue, i, and its C-terminal neighbor, i + 1, in HN-detected double and triple resonance spectra. This leads to the assignment of a tri-peptide segment from the knowledge of the amino acid types of residues: i - 1, i and i + 1, thereby speeding up the sequential assignment process. The method has the advantage of being relatively inexpensive, applicable to {sup 2}H labeled protein and can be coupled with cell-free synthesis and/or automated assignment approaches. A detailed survey involving unlabeling of different amino acid types individually or in pairs reveals that the proposed approach is also robust to misincorporation of {sup 14}N at undesired sites. Taken together, this study represents the first application of selective unlabeling for sequence specific resonance assignments and opens up new avenues to using this methodology in protein structural studies.

  14. Selective adsorption of L- and D-amino acids on calcite: Implications for biochemical homochirality

    Science.gov (United States)

    Hazen, R. M.; Filley, T. R.; Goodfriend, G. A.

    2001-01-01

    The emergence of biochemical homochirality was a key step in the origin of life, yet prebiotic mechanisms for chiral separation are not well constrained. Here we demonstrate a geochemically plausible scenario for chiral separation of amino acids by adsorption on mineral surfaces. Crystals of the common rock-forming mineral calcite (CaCO(3)), when immersed in a racemic aspartic acid solution, display significant adsorption and chiral selectivity of d- and l-enantiomers on pairs of mirror-related crystal-growth surfaces. This selective adsorption is greater on crystals with terraced surface textures, which indicates that d- and l-aspartic acid concentrate along step-like linear growth features. Thus, selective adsorption of linear arrays of d- and l-amino acids on calcite, with subsequent condensation polymerization, represents a plausible geochemical mechanism for the production of homochiral polypeptides on the prebiotic Earth.

  15. Mass spectrometric analysis of selected radiolyzed amino acids in an astrochemical context

    International Nuclear Information System (INIS)

    A selection of amino acids, namely arginine, proline and tyrosine previously irradiated to 3.2 mega-Gray in the solid state and analyzed by differential scanning calorimetry (DSC) and optical rotatory dispersion (ORD) were analyzed in the present work by mass spectrometry with the purpose to identify the radiolysis products and validate the results obtained previously with DSC and ORD. The radiolysis of amino acids is a top-down approach of a research program designed to assess the radiolysis resistance of these molecules for 4.6 x 109 years once buried in primitive bodies of the Solar System. (author)

  16. Plasma amino acids

    Science.gov (United States)

    Amino acids blood test ... types of methods used to determine the individual amino acid levels in the blood. ... test is done to measure the level of amino acids in the blood. An increased level of a ...

  17. Content of amino acids and minerals in selected sorts of legumes

    Directory of Open Access Journals (Sweden)

    Stanislav Kráčmar

    2013-07-01

    Full Text Available Normal 0 21 false false false MicrosoftInternetExplorer4 The aim of this study was to determine amino acid composition and mineral content in selected legume samples. All analyses were carried out at the laboratory temperature of 21±2 °C in triplicate. Amino acid composition was determined using the automatic amino acid analyzer AAA 400 with post-column derivatization. To assess the nutritional value of protein, index of essential amino acids (EAAI was calculated. Minerals were determined using the atomic absorption spectrometer AA 30. All results were statistically evaluated. The highest content of Cys, Glu, Asp, Leu, Lys and Arg was determined in seeds of G. max; only the content of Cys and His was lower than 10 g kg-1. The greatest total content of essential amino acids (EAA was discovered in soybeans, almost 128 g kg-1. The majority (Na, K, Mg, and Ca, trace (Fe, Zn, and Cr and toxic elements (Pb, Cd were determined. Legumes were rich in Mg and Ca-mainly G. max and Ph. vulgaris. The content of Mg was 2.1 g/1000g in soybeans and 1.6 g/1000g in common beans. Also in these two legumes the greatest concentration of toxic Pb was found. Values obtained during the determination of the chemical composition in samples of legumes and buckwheat products can be influenced by many factors, e.g. climatic conditions, location etc.

  18. Plasma amino acids

    Science.gov (United States)

    Plasma amino acids is a screening test done on infants that looks at the amounts of amino ... Laboratory error High or low amounts of individual plasma amino acids must be considered with other information. ...

  19. Selective charging of tRNA isoacceptors induced by amino-acid starvation

    DEFF Research Database (Denmark)

    Dittmar, K. A.; Sørensen, Michael Askvad; Elf, J.;

    2005-01-01

    -acid starvation results in 'selective charging' where the charging levels of some tRNA isoacceptors will be low and those of others will remain high. Here, we developed a microarray for the analysis of charged fractions of tRNAs and measured charging for all Escherichia coli tRNAs before and during leucine......, threonine or arginine starvation. Before starvation, most tRNAs were fully charged. During starvation, the isoacceptors in the leucine, threonine or arginine families showed selective charging when cells were starved for their cognate amino acid, directly confirming the theoretical prediction. Codons read...

  20. MUSIC in triple-resonance experiments: amino acid type-selective (1)H-(15)N correlations

    Science.gov (United States)

    Schubert; Smalla; Schmieder; Oschkinat

    1999-11-01

    Amino acid type-selective triple-resonance experiments can be of great help for the assignment of protein spectra, since they help to remove ambiguities in either manual or automated assignment procedures. Here, modified triple-resonance experiments that yield amino acid type-selective (1)H-(15)N correlations are presented. They are based on novel coherence transfer schemes, the MUSIC pulse sequence elements, that replace the initial INEPT transfer and are selective for XH(2) or XH(3) (X can be (15)N or (13)C). The desired amino acid type is thereby selected based on the topology of the side chain. Experiments for Gly (G-HSQC); Ala (A-HSQC); Thr, Val, Ile, and Ala (TAVI-HSQC); Thr and Ala (TA-HSQC), as well as Asn and Gln (N-HSQC and QN-HSQC), are described. The new experiments are recorded as two-dimensional experiments and therefore need only small amounts of spectrometer time. The performance of the experiments is demonstrated with the application to two protein domains. Copyright 1999 Academic Press. PMID:10527741

  1. Bayes Empirical Bayes Inference of Amino Acid Sites Under Positive Selection

    DEFF Research Database (Denmark)

    Yang, Ziheng; Wong, Wendy Shuk Wan; Nielsen, Rasmus

    2005-01-01

    Codon-based substitution models have been widely used to identify amino acid sites under positive selection in comparative analysis of protein-coding DNA sequences. The nonsynonymous-synonymous substitution rate ratio (dN/dS, denoted ) is used as a measure of selective pressure at the protein level......, with > 1 indicating positive selection. Statistical distributions are used to model the variation in among sites, allowing a subset of sites to have > 1 while the rest of the sequence may be under purifying selection with ... data sets. The results suggest that in small data sets the new BEB method does not generate false positives as did the old NEB approach, while in large data sets it retains the good power of the NEB approach for inferring positively selected sites....

  2. High amino acid diversity and positive selection at a putative coral immunity gene (tachylectin-2

    Directory of Open Access Journals (Sweden)

    Hellberg Michael E

    2010-05-01

    Full Text Available Abstract Background Genes involved in immune functions, including pathogen recognition and the activation of innate defense pathways, are among the most genetically variable known, and the proteins that they encode are often characterized by high rates of amino acid substitutions, a hallmark of positive selection. The high levels of variation characteristic of immunity genes make them useful tools for conservation genetics. To date, highly variable immunity genes have yet to be found in corals, keystone organisms of the world's most diverse marine ecosystem, the coral reef. Here, we examine variation in and selection on a putative innate immunity gene from Oculina, a coral genus previously used as a model for studies of coral disease and bleaching. Results In a survey of 244 Oculina alleles, we find high nonsynonymous variation and a signature of positive selection, consistent with a putative role in immunity. Using computational protein structure prediction, we generate a structural model of the Oculina protein that closely matches the known structure of tachylectin-2 from the Japanese horseshoe crab (Tachypleus tridentatus, a protein with demonstrated function in microbial recognition and agglutination. We also demonstrate that at least three other genera of anthozoan cnidarians (Acropora, Montastrea and Nematostella possess proteins structurally similar to tachylectin-2. Conclusions Taken together, the evidence of high amino acid diversity, positive selection and structural correspondence to the horseshoe crab tachylectin-2 suggests that this protein is 1 part of Oculina's innate immunity repertoire, and 2 evolving adaptively, possibly under selective pressure from coral-associated microorganisms. Tachylectin-2 may serve as a candidate locus to screen coral populations for their capacity to respond adaptively to future environmental change.

  3. HPLC monitoring of spontaneous non-linear peptidization dynamics of selected amino acids in solution.

    Science.gov (United States)

    Godziek, Agnieszka; Maciejowska, Anna; Sajewicz, Mieczysław; Kowalska, Teresa

    2015-03-01

    This is our new study in a series of publications devoted to exploration of applicability of high-performance liquid chromatography (HPLC) to providing answers to difficult questions from the area of the reaction kinetics and mechanisms with non-linear reactions. Although an excellent analytical performance of HPLC is an indisputable fact, so far its performance as a tool in the kinetic and mechanistic studies has been tested to a lesser extent. In our earlier studies, spontaneous peptidization dynamics of amino acids in solution was demonstrated by means of HPLC upon a few amino acid examples, and on that basis a theoretical model has been developed, anticipating an interdependence of dynamics on chemical structures of amino acids involved. In order to expand the spectrum of experimentally investigated amino acid cases, in this study we present the results valid for three novel amino acids of significant life sciences importance, which differ in terms of peptidization dynamics. Experimental evidence originates from the achiral HPLC with the evaporative light scattering detection and MS detection. A conclusion is drawn that different spontaneous peptidization dynamics of amino acids may significantly influence chemical composition of proteins encountered in living organisms. Hence, a need emerges for systematic physicochemical studies on spontaneous non-linear peptidization dynamics of proteinogenic amino acids in liquid abiotic (but also in the biotic) systems.

  4. Amino Acid Crossword Puzzle

    Science.gov (United States)

    Sims, Paul A.

    2011-01-01

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

  5. 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.

    Science.gov (United States)

    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. PMID:24446756

  6. 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.

    Science.gov (United States)

    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.

  7. Azetidinic amino acids

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Bunch, Lennart; Chopin, Nathalie;

    2005-01-01

    A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form fr...

  8. Aldehyde Selective Wacker Oxidations of Phthalimide Protected Allylic Amines : A New Catalytic Route to beta(3)-Amino Acids

    NARCIS (Netherlands)

    Weiner, Barbara; Baeza Garcia, Alejandro; Jerphagnon, Thomas; Feringa, Ben L.

    2009-01-01

    A new method for the synthesis of B-3-amino acids is presented. Phthalimide protected allylic amines are oxidized under Wacker conditions selectively to aldehydes using PdCl2 and CuCl or Pd(MeCN)(2)Cl(NO2) and CuCl2 as complementary catalyst systems. The aldehydes are produced in excellent yields an

  9. Amino acid racemisation dating

    Energy Technology Data Exchange (ETDEWEB)

    Murray-Wallace, C.V. [University of Wollongong, Wollongong, NSW (Australia). School of Geosciences

    1999-11-01

    The potential of the time-dependent amino acid racemisation reaction as a method of age assessment was first reported by Hare and Abelson (1968). They noted that in specimens of the bivalve mollusc Mercenaria sp., greater concentrations of amino acids in the D-configuration with increasing fossil age. Hare and Abelson (1968) also reported negligible racemisation in a modern specimen of Mecanaria sp. On this basis they suggested that the extent of amino acid racemisation (epimerisation in the case of isoleucine) may be used to assess the age of materials within and beyond the range of radiocarbon dating. For the past thirty years amino acid racemisation has been extensively applied in Quaternary research as a method of relative and numeric dating, and a particularly large literature has emerged on the subject 12 refs.

  10. Amino Acid Metabolism Disorders

    Science.gov (United States)

    Metabolism is the process your body uses to make energy from the food you eat. Food is ... One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup ...

  11. Novel 3-carboxy- and 3-phosphonopyrazoline amino acids as potent and selective NMDA receptor antagonists

    DEFF Research Database (Denmark)

    Conti, Paola; Pinto, Andrea; Tamborini, Lucia;

    2010-01-01

    The design and synthesis of new N1-substituted 3-carboxy- and 3-phosphonopyrazoline and pyrazole amino acids that target the glutamate binding site of NMDA receptors are described. An analysis of the stereochemical requirements for high-affinity interaction with these receptors was performed. We ...

  12. Facile Synthesis of Gold Nanoparticles by Amino Acid Asparagine: Selective Sensing of Arsenic.

    Science.gov (United States)

    Ghodake, Gajanan; Vassiliadis, Vassilios S; Choi, Jeong-Hak; Jang, Jiseon; Lee, Dae Sung

    2015-09-01

    The amino acid asparagine (ASP) was used as a benign reducing and stabilizing agent for the production of monodisperse gold nanoparticles (AuNPs) using green chemistry principles. With an increasing concentration of ASP (0.5 to 10 mM), the absorbance intensity at 525 nm increased; however, no effects on the color, size, or shape of the AuNPs were observed. Transmission electron microscope (TEM) images showed that the AuNPs were either hexagonal or spherical in shape and had an average size of approximately 10 ± 5 nm. Facile colorimetric assays of the AuNPs were applied to detect a variety of heavy metal ion species in water. In this study, the selective detection of arsenic ions (As (III) ions) by quenching, aggregation, and/or red-shifting of the surface plasmon resonance (SPR) was successfully achieved. The AuNPs sensor was sustainable as a visual colorimetric detection system and spectral assay of hazardous As (III) ions in the reaction medium; thus, it will be useful for aqueous assessment without using any sophisticated or expensive instruments. PMID:26716315

  13. Chiral selectivity of amino acid adsorption on chiral surfaces—The case of alanine on Pt

    Energy Technology Data Exchange (ETDEWEB)

    Franke, J.-H.; Kosov, D. S. [Department of Physics, Campus Plaine - CP 231, Université Libre de Bruxelles, 1050 Brussels (Belgium)

    2015-02-07

    We study the binding pattern of the amino acid alanine on the naturally chiral Pt surfaces Pt(531), Pt(321), and Pt(643). These surfaces are all vicinal to the (111) direction but have different local environments of their kink sites and are thus a model for realistic roughened Pt surfaces. Alanine has only a single methyl group attached to its chiral center, which makes the number of possible binding conformations computationally tractable. Additionally, only the amine and carboxyl group are expected to interact strongly with the Pt substrate. On Pt(531), we study the molecule in its pristine as well as its deprotonated form and find that the deprotonated one is more stable by 0.47 eV. Therefore, we study the molecule in its deprotonated form on Pt(321) and Pt(643). As expected, the oxygen and nitrogen atoms of the deprotonated molecule provide a local binding “tripod” and the most stable adsorption configurations optimize the interaction of this “tripod” with undercoordinated surface atoms. However, the interaction of the methyl group plays an important role: it induces significant chiral selectivity of about 60 meV on all surfaces. Hereby, the L-enantiomer adsorbs preferentially to the Pt(321){sup S} and Pt(643){sup S} surfaces, while the D-enantiomer is more stable on Pt(531){sup S}. The binding energies increase with increasing surface density of kink sites, i.e., they are largest for Pt(531){sup S} and smallest for Pt(643){sup S}.

  14. Electrodialytic removal of nitrate from pineapple juice: effect on selected physicochemical properties, amino acids, and aroma components of the juice.

    Science.gov (United States)

    Ackarabanpojoue, Yuwadee; Chindapan, Nathamol; Yoovidhya, Tipaporn; Devahastin, Sakamon

    2015-05-01

    This study aimed at investigating the effect of nitrate removal from pineapple juice by electrodialysis (ED) on selected properties of the ED-treated juice. Single-strength pineapple juice with reduced pulp content was treated by ED to reduce the nitrate concentration to 15, 10, or 5 ppm. After ED, the removed pulp was added to the ED-treated juice and its properties, including electrical conductivity, acidity, pH, total soluble solids (TSS), color, amino acids, and selected aroma compounds, were determined and compared with those of the untreated juice. ED could reduce the nitrate content of 1 L of pineapple juice from an initial value of 50 ppm to less than 5 ppm within 30 min. A significant decrease in the electrical conductivity, acidity, pH, TSS, and yellowness, but a significant increase in the lightness, of the juice was observed upon ED. Concentrations of almost all amino acids of the ED-treated juice significantly decreased. The concentrations of 8 major compound contributors to the pineapple aroma also significantly decreased. Adding the pulp back to the ED-treated juice increased the amino acids concentrations; however, it led to a significant decrease in the concentrations of the aroma compounds.

  15. NMR conformational properties of an Anthrax Lethal Factor domain studied by multiple amino acid-selective labeling

    Energy Technology Data Exchange (ETDEWEB)

    Vourtsis, Dionysios J.; Chasapis, Christos T.; Pairas, George [Department of Pharmacy, University of Patras, GR-26504 Patras (Greece); Bentrop, Detlef [Institute of Physiology II, University of Freiburg, D-79104 Freiburg (Germany); Spyroulias, Georgios A., E-mail: G.A.Spyroulias@upatras.gr [Department of Pharmacy, University of Patras, GR-26504 Patras (Greece)

    2014-07-18

    Highlights: • A polypeptide, N-ALF{sub 233}, was overexpressed in E. coli and successfully isolated. • We produced {sup 2}H/{sup 15}N/{sup 13}C labeled protein samples. • Amino acid selective approaches were applied. • We acquired several heteronuclear NMR spectra, to complete the backbone assignment. • Prediction of the secondary structure was performed. - Abstract: NMR-based structural biology urgently needs cost- and time-effective methods to assist both in the process of acquiring high-resolution NMR spectra and their subsequent analysis. Especially for bigger proteins (>20 kDa) selective labeling is a frequently used means of sequence-specific assignment. In this work we present the successful overexpression of a polypeptide of 233 residues, corresponding to the structured part of the N-terminal domain of Anthrax Lethal Factor, using Escherichia coli expression system. The polypeptide was subsequently isolated in pure, soluble form and analyzed structurally by solution NMR spectroscopy. Due to the non-satisfying quality and resolution of the spectra of this 27 kDa protein, an almost complete backbone assignment became feasible only by the combination of uniform and novel amino acid-selective labeling schemes. Moreover, amino acid-type selective triple-resonance NMR experiments proved to be very helpful.

  16. A new structural class of subtype-selective inhibitor of cloned excitatory amino acid transporter, EAAT2

    DEFF Research Database (Denmark)

    Bräuner-Osborne, Hans; Hermit, M B; Nielsen, B;

    2000-01-01

    We have studied the pharmacological effects of (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) and the enantiomers of (RS)-2-amino-3-(3-hydroxy-1,2, 5-thiadiazol-4-yl)propionic acid (TDPA) on cloned human excitatory amino acid transporter subtypes 1, 2 and 3 (EAAT1-3) expres...

  17. Selective Oxidative Decarboxylation of Amino Acids to Produce Industrially Relevant Nitriles by Vanadium Chloroperoxidase

    NARCIS (Netherlands)

    But, A.; Notre, le J.E.L.; Scott, E.L.; Wever, R.; Sanders, J.P.M.

    2012-01-01

    Industrial nitriles from biomass: Vanadium-chloroperoxidase is successfully used to transform selectively glutamic acid into 3-cyanopropanoic acid, a key intermediate for the synthesis of bio-succinonitrile and bio-acrylonitrile, by using a catalytic amount of a halide salt. This clean oxidative dec

  18. Positive selection results in frequent reversible amino acid replacements in the G protein gene of human respiratory syncytial virus.

    Directory of Open Access Journals (Sweden)

    Viviane F Botosso

    2009-01-01

    Full Text Available Human respiratory syncytial virus (HRSV is the major cause of lower respiratory tract infections in children under 5 years of age and the elderly, causing annual disease outbreaks during the fall and winter. Multiple lineages of the HRSVA and HRSVB serotypes co-circulate within a single outbreak and display a strongly temporal pattern of genetic variation, with a replacement of dominant genotypes occurring during consecutive years. In the present study we utilized phylogenetic methods to detect and map sites subject to adaptive evolution in the G protein of HRSVA and HRSVB. A total of 29 and 23 amino acid sites were found to be putatively positively selected in HRSVA and HRSVB, respectively. Several of these sites defined genotypes and lineages within genotypes in both groups, and correlated well with epitopes previously described in group A. Remarkably, 18 of these positively selected tended to revert in time to a previous codon state, producing a "flip-flop" phylogenetic pattern. Such frequent evolutionary reversals in HRSV are indicative of a combination of frequent positive selection, reflecting the changing immune status of the human population, and a limited repertoire of functionally viable amino acids at specific amino acid sites.

  19. Amino acid analysis.

    Science.gov (United States)

    Crabb, J W; West, K A; Dodson, W S; Hulmes, J D

    2001-05-01

    Amino acid analysis (AAA) is one of the best methods to quantify peptides and proteins. Two general approaches to quantitative AAA exist, namely, classical postcolumn derivatization following ion-exchange chromatography and precolumn derivatization followed by reversed-phase HPLC (RP-HPLC). Excellent instrumentation and several specific methodologies are available for both approaches, and both have advantages and disadvantages. This unit focuses on picomole-level AAA of peptides and proteins using the most popular precolumn-derivatization method, namely, phenylthiocarbamyl amino acid analysis (PTC-AAA). It is directed primarily toward those interested in establishing the technology with a modest budget. PTC derivatization and analysis conditions are described, and support and alternate protocols describe additional techniques necessary or useful for most any AAA method--e.g., sample preparation, hydrolysis, instrument calibration, data interpretation, and analysis of difficult or unusual residues such as cysteine, tryptophan, phosphoamino acids, and hydroxyproline. PMID:18429107

  20. Pairwise amino acid secondary structural propensities

    Science.gov (United States)

    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.

  1. Synthesis of new isoxazoline-based acidic amino acids and investigation of their affinity and selectivity profile at ionotropic glutamate receptors

    DEFF Research Database (Denmark)

    Pinto, Andrea; Conti, Paola; Grazioso, Giovanni;

    2011-01-01

    The synthesis of four new isoxazoline-based amino acids being analogues of previously described glutamate receptor ligands is reported and their affinity for ionotropic glutamate receptors is analyzed in comparison with that of selected model compounds. Molecular modelling investigations have bee...

  2. Relationship between amino acid usage and amino acid evolution in primates.

    Science.gov (United States)

    Liu, Haoxuan; Xie, Zhengqing; Tan, Shengjun; Zhang, Xiaohui; Yang, Sihai

    2015-02-25

    Amino acid usage varies from species to species. A previous study has found a universal trend in amino acid gain and loss in many taxa and a one-way model of amino acid evolution in which the number of new amino acids increases as the number of old amino acids decreases was proposed. Later studies showed that this pattern of amino acid gain and loss is likely to be compatible with the neutral theory. The present work aimed to further study this problem by investigating the evolutionary patterns of amino acids in 8 primates (the nucleotide and protein alignments are available online http://gattaca.nju.edu.cn/pub_data.html). First, the number of amino acids gained and lost was calculated and the evolution trend of each amino acid was inferred. These values were found to be closely related to the usage of each amino acid. Then we analyzed the mutational trend of amino acid substitution in human using SNPs, this trend is highly correlated with fixation trend only with greater variance. Finally, the trends in the evolution of 20 amino acids were evaluated in human on different time scales, and the increasing rate of 5 significantly increasing amino acids was found to decrease as a function of time elapsed since divergence, and the dS/dN ratio also found to increase as a function of time elapsed since divergence. These results suggested that the observed amino acid substitution pattern is influenced by mutation and purifying selection. In conclusion, the present study shows that usage of amino acids is an important factor capable of influencing the observed pattern of amino acid evolution, and also presented evidences suggesting that the observed universal trend of amino acid gain and loss is compatible with neutral evolution. PMID:25527119

  3. Ionotropic excitatory amino acid receptor ligands. Synthesis and pharmacology of a new amino acid AMPA antagonist

    DEFF Research Database (Denmark)

    Madsen, U; Sløk, F A; Stensbøl, T B;

    2000-01-01

    We have previously described the potent and selective (RS)-2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, (RS)-2-amino-3-(3-carboxy-5-methyl-4-isoxazolyl)propionic acid (ACPA), and the AMPA receptor antagonist (RS)-2-amino-3-[3-(carboxymethoxy)-5-methyl-4-isoxa...

  4. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Science.gov (United States)

    Prati, Federica; Goldman-Pinkovich, Adele; Lizzi, Federica; Belluti, Federica; Koren, Roni; Zilberstein, Dan; Bolognesi, Maria Laura

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes) and intracellular (amastigotes) forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively). Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives. PMID:25254495

  5. Quinone-amino acid conjugates targeting Leishmania amino acid transporters.

    Directory of Open Access Journals (Sweden)

    Federica Prati

    Full Text Available The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7 to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III with amino acids (i.e. arginine and lysine by means of an amide linkage. The toxicity of the synthesized conjugates against Leishmania extracellular (promastigotes and intracellular (amastigotes forms was investigated, as well their inhibition of the relevant amino acid transporters. We observed that some conjugates indeed displayed toxicity against the parasites; in particular, 7 was identified as the most potent derivative (at concentrations of 1 µg/mL and 2.5 µg/mL residual cell viability was reduced to 15% and 48% in promastigotes and amastigotes, respectively. Notably, 6, while retaining the cytotoxic activity of quinone II, displayed no toxicity against mammalian THP1 cells. Transport assays indicated that the novel conjugates inhibited transport activity of lysine, arginine and proline transporters. Furthermore, our analyses suggested that the toxic conjugates might be translocated by the transporters into the cells. The non-toxic probes that inhibited transport competed with the natural substrates for binding to the transporters without being translocated. Thus, it is likely that 6, by exploiting amino acid transporters, can selectively deliver its toxic effects to Leishmania cells. This work provides the first evidence that amino acid transporters of the human pathogen Leishmania might be modulated by small molecules, and warrants their further investigation from drug discovery and chemical biology perspectives.

  6. Marked increase in PROP taste responsiveness following oral supplementation with selected salivary proteins or their related free amino acids.

    Directory of Open Access Journals (Sweden)

    Melania Melis

    Full Text Available The genetic predisposition to taste 6-n-propylthiouracil (PROP varies among individuals and is associated with salivary levels of Ps-1 and II-2 peptides, belonging to the basic proline-rich protein family (bPRP. We evaluated the role of these proteins and free amino acids that selectively interact with the PROP molecule, in modulating bitter taste responsiveness. Subjects were classified by their PROP taster status based on ratings of perceived taste intensity for PROP and NaCl solutions. Quantitative and qualitative determinations of Ps-1 and II-2 proteins in unstimulated saliva were performed by HPLC-ESI-MS analysis. Subjects rated PROP bitterness after supplementation with Ps-1 and II-2, and two amino acids (L-Arg and L-Lys whose interaction with PROP was demonstrated by (1H-NMR spectroscopy. ANOVA showed that salivary levels of II-2 and Ps-1 proteins were higher in unstimulated saliva of PROP super-tasters and medium tasters than in non-tasters. Supplementation of Ps-1 protein in individuals lacking it in saliva enhanced their PROP bitter taste responsiveness, and this effect was specific to the non-taster group.(1H-NMR results showed that the interaction between PROP and L-Arg is stronger than that involving L-Lys, and taste experiments confirmed that oral supplementation with these two amino acids increased PROP bitterness intensity, more for L-Arg than for L-Lys. These data suggest that Ps-1 protein facilitates PROP bitter taste perception and identifies a role for free L-Arg and L-Lys in PROP tasting.

  7. Long-term effect of dexfenfluramine on amino acid profiles and food selection in obese patients during weight loss

    DEFF Research Database (Denmark)

    Breum, L; Møller, S E; Andersen, T;

    1996-01-01

    .2-5.0 MJ/d diet. Maximum weight loss was obtained after 6 months (dF 12.8 +/- 5.4 kg; PL 13.8 +/- 9.2 kg, x +/- s.d., ns). Plasma Trp/LNAA and Tyr/LNAA were found to be lower than in normal weight controls and were further reduced during treatment (p ... groups. Macronutrient selection was not affected by the dF treatment. In the placebo group weight loss was associated with a high pre-treatment energy intake and a high carbohydrate-protein ratio (p protein intake (%) and age was found to explain 82......% of the variation in weight loss (p food selection nor basal plasma amino acid profiles were predictors of weight loss during long-term treatment...

  8. Amino acids in Arctic aerosols

    Directory of Open Access Journals (Sweden)

    E. Scalabrin

    2012-07-01

    Full Text Available Amino acids are significant components of atmospheric aerosols, affecting organic nitrogen input to marine ecosystems, atmospheric radiation balance, and the global water cycle. The wide range of amino acid reactivities suggest that amino acids may serve as markers of atmospheric transport and deposition of particles. Despite this potential, few measurements have been conducted in remote areas to assess amino acid concentrations and potential sources. Polar regions offer a unique opportunity to investigate atmospheric processes and to conduct source apportionment studies of such compounds. In order to better understand the importance of amino acid compounds in the global atmosphere, we determined free amino acids (FAAs in seventeen size-segregated aerosol samples collected in a polar station in the Svalbard Islands from 19 April until 14 September 2010. We used an HPLC coupled with a tandem mass spectrometer (ESI-MS/MS to analyze 20 amino acids to quantify compounds at fmol m−3 levels. Mean total FAA concentration was 1070 fmol m−3 where serine and glycine were the most abundant compounds in almost all samples and accounted for 45–60% of the total amino acid relative abundance. The other eighteen compounds had average concentrations between 0.3 and 98 fmol m−3. The higher amino acid concentrations were present in the ultrafine aerosol fraction (<0.49 μm and accounted for the majority of the total amino acid content. Local marine sources dominate the boreal summer amino acid concentrations, with the exception of the regional input from Icelandic volcanics.

  9. Highly selective hydrocarboxylation of styrene with oxalic acid or water using palladium ortho-amino arenethiolates with intramolecular co-ordinating nitrogen Lewis bases

    NARCIS (Netherlands)

    Koten, G. van; Kruis, D.; Ruiz, N.; Janssen, M.D.; Boersma, J.; Claver, C.

    1998-01-01

    Under mild conditions and in the presence of a catalytic amount of an S, N-chelated palladium ortho-amino arenethiolate complex, styrene reacts with carbon monoxide and oxalic acid or water to selectively give 2-phenylpropanoic acid in high yield.

  10. Microfluidics in amino acid analysis.

    Science.gov (United States)

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  11. Amino Acids from a Comet

    Science.gov (United States)

    Cook, Jamie Elisla

    2009-01-01

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

  12. Influence of selected lab cultures on the evolution of free amino acids, free fatty acids and Fiore Sardo cheese microflora during the ripening.

    Science.gov (United States)

    Mangia, Nicoletta P; Murgia, Marco A; Garau, Giovanni; Sanna, Maria G; Deiana, Pietrino

    2008-04-01

    Fiore Sardo Protected Denomination of Origin is a traditional Sardinian (Italy) hard cheese produced exclusively from whole raw ovine milk and coagulated with lamb rennet paste. Currently, Fiore Sardo is still produced by shepherds at the farmhouse level without the addition of any starter culture and the cheese-making process is characterized by significant waste. The first objective of the present work was to investigate the autochthonous microflora present in milk and Fiore Sardo cheese in order to select lactic acid bacterial (LAB) cultures with suitable cheese-making attributes and, possibly reduce the production waste. Secondly, the ability of selected cultures to guarantee cheese healthiness and quality was tested in experimental cheese-making trials. In this study, we show that the typical lactic microflora of raw ewe's milk and Fiore Sardo cheese is mostly composed of mesophilic LAB such as Lactococcus lactis subsp. lactis, Lactobacillus plantarum and Lactobacillus casei subsp. casei. Moreover, strains belonging to the species were selected for cheese-making attributes and used in experimental cheese-making trials carried out in different farms producing Fiore Sardo. The evolution of the cheese microflora, free amino acids and free fatty acids during the ripening showed that the experimental cheeses were characterized by a balanced ratio of the chemical constituents, by a reduced number of spoilage microorganisms and, remarkably, by the absence of production waste that were significant for the control cheeses.

  13. A potential new selection criterion for breeding winter barley optimal protein and amino acid profiles for liquid pig feed

    DEFF Research Database (Denmark)

    Christensen, Jesper Bjerg; Blaabjerg, Karoline; Poulsen, Hanne Damgaard

    for amino acid analysis of water soluble protein at 4, 6 and 48 hours. The amount of glutamic acid after 48 hours indicated that the solubilised protein originated from the prolamin fraction in the grain. Comparison of the amount of isoleucine, leucine, phenylalanine and histidine in relation to the amount......The hypothesis is that cereal proteases in liquid feed degrade and convert water insoluble storage protein into water soluble protein, which may improve the digestibility of protein in pigs compared with dry feeding. Protein utilization is increased by matching the amino acid (AAs) content...... of the diet as close as possible to the pigs’ requirement. By improving the availability of isoleucine, leucine, histidine and phenylalanine, which are limiting and commercial unavailable, the amount of crude protein in the pig feed can be reduced, resulting in a decreased excretion of nitrogen. The aim...

  14. Selective antagonists at group I metabotropic glutamate receptors: synthesis and molecular pharmacology of 4-aryl-3-isoxazolol amino acids

    DEFF Research Database (Denmark)

    Kromann, Hasse; Sløk, Frank A; Stensbøl, Tine B;

    2002-01-01

    Homologation of (S)-glutamic acid (Glu, 1) and Glu analogues has previously provided ligands with activity at metabotropic Glu receptors (mGluRs). The homologue of ibotenic acid (7), 2-amino-3-(3-hydroxy-5-isoxazolyl)propionic acid (HIBO, 8), and the 4-phenyl derivative of 8, compound 9a, are bot...... antagonists at group I mGluRs. Here we report the synthesis and molecular pharmacology of HIBO analogues 9b-h containing different 4-aryl substituents. All of these compounds possess antagonist activity at group I mGluRs but are inactive at group II and III mGluRs....

  15. Hybrid gold single crystals incorporating amino acids

    CERN Document Server

    Chen, Linfeng; Weber, Eva; Fitch, Andy N; Pokroy, Boaz

    2016-01-01

    Composite hybrid gold crystals are of profound interest in various research areas ranging from materials science to biology. Their importance is due to their unique properties and potential implementation, for example in sensing or in bio-nanomedicine. Here we report on the formation of hybrid organic-metal composites via the incorporation of selected amino acids histidine, aspartic acid, serine, glutamine, alanine, cysteine, and selenocystine into the crystal lattice of single crystals of gold. We used electron microscopy, chemical analysis and high-resolution synchrotron powder X ray diffraction to examine these composites. Crystal shape, as well as atomic concentrations of occluded amino acids and their impact on the crystal structure of gold, were determined. Concentration of the incorporated amino acid was highest for cysteine, followed by serine and aspartic acid. Our results indicate that the incorporation process probably occurs through a complex interaction of their individual functional groups with ...

  16. Synthesis and pharmacology of 3-isoxazolol amino acids as selective antagonists at group I metabotropic glutamic acid receptors

    DEFF Research Database (Denmark)

    Madsen, U; Bräuner-Osborne, H; Frydenvang, Karla Andrea;

    2001-01-01

    to originate in (S)-11 (EC(50) = 395 microM, K(b) = 86 and 90 microM, respectively). Compound 9, administered icv, but not sc, was shown to protect mice against convulsions induced by N-methyl-D-aspartic acid (NMDA). Compounds 9 and 11 were resolved using chiral HPLC, and the configurational assignments...

  17. Single substitutions to closely related amino acids contribute to the functional diversification of an insect-inducible, positively selected plant cystatin.

    Science.gov (United States)

    Rasoolizadeh, Asieh; Goulet, Marie-Claire; Sainsbury, Frank; Cloutier, Conrad; Michaud, Dominique

    2016-04-01

    A causal link has been reported between positively selected amino acids in plant cystatins and the inhibitory range of these proteins against insect digestive cysteine (Cys) proteases. Here we assessed the impact of single substitutions to closely related amino acids on the contribution of positive selection to cystatin diversification. Cystatin sequence alignments, while confirming hypervariability, indicated a preference for related amino acids at positively selected sites. For example, the non-polar residues leucine (Leu), isoleucine (Ile) and valine (Val) were shown to predominate at positively selected site 2 in the N-terminal region, unlike selected sites 6 and 10, where polar residues are preferred. The model cystatin SlCYS8 and single variants with Leu, Ile or Val at position 2 were compared with regard to their ability to bind digestive proteases of the coleopteran pest Leptinotarsa decemlineata and to induce compensatory responses in this insect. A functional proteomics procedure to capture target Cys proteases in midgut extracts allowed confirmation of distinct binding profiles for the cystatin variants. A shotgun proteomics procedure to monitor whole Cys protease complements revealed protease family specific compensatory responses in the insect, dependent on the variant ingested. Our data confirm the contribution of closely related amino acids to the functional diversity of positively selected plant cystatins in a broader structure/function context imposing physicochemical constraints to primary structure alterations. They also underline the complexity of protease/inhibitor interactions in plant-insect systems, and the challenges still to be met in order to harness the full potential of ectopically expressed protease inhibitors in crop protection.

  18. Use of a Plackett-Burman statistical design to determine the effect of selected amino acids on monoclonal antibody production in CHO cells.

    Science.gov (United States)

    González-Leal, I J; Carrillo-Cocom, L M; Ramírez-Medrano, A; López-Pacheco, F; Bulnes-Abundis, D; Webb-Vargas, Y; Alvarez, M M

    2011-01-01

    Culture media design is central to the optimization of monoclonal antibody (mAb) production. Although general strategies do not currently exist for optimization of culture media, the combined use of statistical design and analysis of experiments and strategies based on simple material balances can facilitate culture media design. In this study, we evaluate the effect of selected amino acids on the growth rate and monoclonal antibody production of a Chinese hamster ovary DG-44 (CHO-DG44) cell line. These amino acids were selected based on their relative mass fraction in the specific mAb produced in this study, their consumption rate during bioreactor experiments, and also through a literature review. A Plackett-Burman statistical design was conducted to minimize the number of experiments needed to obtain statistically relevant information. The effect of this set of amino acids was evaluated during exponential cell culture (considering viable cell concentration and the specific growth rate as main output variables) and during the high cell-density stage (considering mAb final concentration and specific productivity as relevant output variables). For this particular cell line, leucine (Leu) and arginine (Arg) had the highest negative and positive effects on cell viability, respectively; Leu and threonine (Thr) had the highest negative effect on growth rate, and valine (Val) and Arg demonstrated the highest positive impact on mAb final concentration. Results suggest the pertinence of a two-stage strategy for amino acid supplementation, with a mixture optimized for cell growth and a different amino acid mixture for mAb production at high density.

  19. Combinatorics of aliphatic amino acids.

    Science.gov (United States)

    Grützmann, Konrad; Böcker, Sebastian; Schuster, Stefan

    2011-01-01

    This study combines biology and mathematics, showing that a relatively simple question from molecular biology can lead to complicated mathematics. The question is how to calculate the number of theoretically possible aliphatic amino acids as a function of the number of carbon atoms in the side chain. The presented calculation is based on earlier results from theoretical chemistry concerning alkyl compounds. Mathematical properties of this number series are highlighted. We discuss which of the theoretically possible structures really occur in living organisms, such as leucine and isoleucine with a chain length of four. This is done both for a strict definition of aliphatic amino acids only involving carbon and hydrogen atoms in their side chain and for a less strict definition allowing sulphur, nitrogen and oxygen atoms. While the main focus is on proteinogenic amino acids, we also give several examples of non-proteinogenic aliphatic amino acids, playing a role, for instance, in signalling. The results are in agreement with a general phenomenon found in biology: Usually, only a small number of molecules are chosen as building blocks to assemble an inconceivable number of different macromolecules as proteins. Thus, natural biological complexity arises from the multifarious combination of building blocks.

  20. Prediction of Golgi-resident protein types using general form of Chou's pseudo-amino acid compositions: Approaches with minimal redundancy maximal relevance feature selection.

    Science.gov (United States)

    Jiao, Ya-Sen; Du, Pu-Feng

    2016-08-01

    Recently, several efforts have been made in predicting Golgi-resident proteins. However, it is still a challenging task to identify the type of a Golgi-resident protein. Precise prediction of the type of a Golgi-resident protein plays a key role in understanding its molecular functions in various biological processes. In this paper, we proposed to use a mutual information based feature selection scheme with the general form Chou's pseudo-amino acid compositions to predict the Golgi-resident protein types. The positional specific physicochemical properties were applied in the Chou's pseudo-amino acid compositions. We achieved 91.24% prediction accuracy in a jackknife test with 49 selected features. It has the best performance among all the present predictors. This result indicates that our computational model can be useful in identifying Golgi-resident protein types. PMID:27155042

  1. Quinone-Amino Acid Conjugates Targeting Leishmania Amino Acid Transporters

    OpenAIRE

    Federica Prati; Adele Goldman-Pinkovich; Federica Lizzi; Federica Belluti; Roni Koren; Dan Zilberstein; Maria Laura Bolognesi

    2014-01-01

    The aim of the present study was to investigate the feasibility of targeting Leishmania transporters via appropriately designed chemical probes. Leishmania donovani, the parasite that causes visceral leishmaniasis, is auxotrophic for arginine and lysine and has specific transporters (LdAAP3 and LdAAP7) to import these nutrients. Probes 1-15 were originated by conjugating cytotoxic quinone fragments (II and III) with amino acids (i.e. arginine and lysine) by means of an amide linkage. The toxi...

  2. Selective Adsorption and Chiral Amplification of Amino Acids in Vermiculite Clay -Implications for the origin of biochirality

    CERN Document Server

    Fraser, Donald G; Jakschitz, Thomas; Rode, Bernd M

    2010-01-01

    Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH3Cl ions, forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. N-propyl NH3Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic o...

  3. Excitatory amino acid receptor antagonists

    DEFF Research Database (Denmark)

    Johansen, T N; Frydenvang, Karla Andrea; Ebert, B;

    1997-01-01

    We have previously shown that (RS)-2-amino-2-(5-tert-butyl-3-hydroxyisoxazol-4-yl)acetic acid (ATAA) is an antagonist at N-methyl-D-aspartic acid (NMDA) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propionic acid (AMPA) receptors. We have now resolved ATAA via diastereomeric salt formation......)-phenylethylamine salt of N-BOC-(R)-ATAA. Like ATAA, neither (R)- nor (S)-ATAA significantly affected (IC50 > 100 microM) the receptor binding of tritiated AMPA, kainic acid, or (RS)-3-(2-carboxypiperazin-4-yl)propyl-1-phosphonic acid, the latter being a competitive NMDA antagonist. Electrophysiological experiments......, using the rat cortical wedge preparation, showed the NMDA antagonist effect as well as the AMPA antagonist effect of ATAA to reside exclusively in the (R)-enantiomer (Ki = 75 +/- 5 microM and 57 +/- 1 microM, respectively). Neither (R)- nor (S)-ATAA significantly reduced kainic acid-induced excitation...

  4. [Inherited amino acid transport disorders].

    Science.gov (United States)

    Igarashi, Y; Tada, K

    1992-07-01

    Disorders due to inherited amino acids transport defect are reviewed. The disorders were categorized into three types of transport defects, namely, brush-border membrane of epithelial cells of small intestine and kidney tubules (Hartnup disease, blue diaper syndrome, cystinuria, iminoglycinuria and lysine malabsorption syndrome), basolateral membrane (lysinuric protein intolerance) and membrane of intracellular organelles (cystinosis and hyperornitinemia-hyperammonemia-homocitrullinuria syndrome). Pathogenesis, clinical feature, laboratory findings, diagnosis, genetics and treatment of these disorders are described, briefly. There is not much data for the transport systems themselves, so that further investigation in molecular and gene levels for transport systems is necessary to clarify the characteristics of the transport and heterogeneity of phenotypes in inherited amino acids transport disorders. PMID:1404888

  5. A new strategy for the selective determination of D-amino acids: enzymatic and chemical modifications for pre-column derivatization.

    Science.gov (United States)

    Oguri, Shigeyuki; Nomura, Michiko; Fujita, Youko

    2005-06-17

    A new strategy for the selective determination of D-amino acids (DAAs) employing a pre-column derivatization was designed with concepts based on both enzymatic and chemical modifications. Selective determination of DAAs was accomplished by following: DAA was enzymatically modified with D-amino acid oxidase (DAAO: EC 1.4.3.3) to form an alpha-keto acid. Subsequently, resulting alpha-keto acid was detected by high-performance liquid chromatography (HPLC) after chemical modification with o-phenylenediamine (PDA) in the presence of 2-mercaptoethanol (2ME) to give the corresponding quinoxalinol derivative (PDA-alpha-keto acid derivative). After optimizing the pre-column derivatization and HPLC separation, five peaks corresponding to DAAs (D-alanine, D-leucine, D-methionine, D-phenylalanine, D-valine (as the standard mixture of DAAs in this paper) were separately eluted and monitored by means of a conventional HPLC system with a gradient elution on octadecyl silica gel (ODS) column and a fluorescence detector (Ex.: 341 nm, Em.: 413 nm), respectively. It was confirmed that the present method was incapable of detecting L-amino acids (LAA) when a sample solution consisting of both LAAs and DAAs was examined. The linearity of the peak-area responses to their concentration range of DAAs from 10 to 500 microM is 0.994-1.000, and their detection limits were 0.2-1 microM (signal/noise = 3). When this method was applied to a methanolic extract of short-necked clams, Ruditapes philippinarum (in Japanese, Asari), a big peak, corresponding to D-alanine was detected, corresponding to 2.9 mg/g D-alanine. In this paper, we present an example of pre-column derivatization method that was newly configured to take into account both the biological and chemical properties of the substances in question. PMID:16007981

  6. Alpha-amino acid behaves differently from beta- or gamma-amino acids as treated by trimetaphosphate.

    Science.gov (United States)

    Gao, X; Liu, Y; Xu, P X; Cai, Y M; Zhao, Y F

    2008-01-01

    The condensation reactions of sodium trimetaphosphate with single amino acids, namely glycine, L-alanine, beta-alanine and gamma-aminobutyric acid or pairs of these amino acids were reinvestigated by electrospray ion-trap mass spectrometry and high performance liquid chromatography. It was found when mixtures were treated by sodium trimetaphosphate only in the presence of alpha-amino acid dipeptides were formed. Without addition of alpha-amino acids, the beta-amino acid or gamma-aminobutyric acid could not form peptide either by themselves or with their mixtures under the same conditions. From the data it is concluded that phosphate might select alpha-amino acids to produce the peptides being important precursors for the origin of life. PMID:17973074

  7. Evolutionary systems biology of amino acid biosynthetic cost in yeast.

    Directory of Open Access Journals (Sweden)

    Michael D Barton

    Full Text Available Every protein has a biosynthetic cost to the cell based on the synthesis of its constituent amino acids. In order to optimise growth and reproduction, natural selection is expected, where possible, to favour the use of proteins whose constituents are cheaper to produce, as reduced biosynthetic cost may confer a fitness advantage to the organism. Quantifying the cost of amino acid biosynthesis presents challenges, since energetic requirements may change across different cellular and environmental conditions. We developed a systems biology approach to estimate the cost of amino acid synthesis based on genome-scale metabolic models and investigated the effects of the cost of amino acid synthesis on Saccharomyces cerevisiae gene expression and protein evolution. First, we used our two new and six previously reported measures of amino acid cost in conjunction with codon usage bias, tRNA gene number and atomic composition to identify which of these factors best predict transcript and protein levels. Second, we compared amino acid cost with rates of amino acid substitution across four species in the genus Saccharomyces. Regardless of which cost measure is used, amino acid biosynthetic cost is weakly associated with transcript and protein levels. In contrast, we find that biosynthetic cost and amino acid substitution rates show a negative correlation, but for only a subset of cost measures. In the economy of the yeast cell, we find that the cost of amino acid synthesis plays a limited role in shaping transcript and protein expression levels compared to that of translational optimisation. Biosynthetic cost does, however, appear to affect rates of amino acid evolution in Saccharomyces, suggesting that expensive amino acids may only be used when they have specific structural or functional roles in protein sequences. However, as there appears to be no single currency to compute the cost of amino acid synthesis across all cellular and environmental

  8. Selective adsorption and chiral amplification of amino acids in vermiculite clay-implications for the origin of biochirality.

    Science.gov (United States)

    Fraser, Donald G; Fitz, Daniel; Jakschitz, T; Rode, Bernd M

    2011-01-21

    Smectite clays are hydrated layer silicates that, like micas, occur naturally in abundance. Importantly, they have readily modifiable interlayer spaces that provide excellent sites for nanochemistry. Vermiculite is one such smectite clay and in the presence of small chain-length alkyl-NH(3)Cl ions forms sensitive, 1-D ordered model clay systems with expandable nano-pore inter-layer regions. These inter-layers readily adsorb organic molecules. n-Propyl NH(3)Cl vermiculite clay gels were used to determine the adsorption of alanine, lysine and histidine by chiral HPLC. The results show that during reaction with fresh vermiculite interlayers, significant chiral enrichment of either L- and D-enantiomers occurs depending on the amino acid. Chiral enrichment of the supernatant solutions is up to about 1% per pass. In contrast, addition to clay interlayers already reacted with amino acid solutions resulted in little or no change in D/L ratio during the time of the experiment. Adsorption of small amounts of amphiphilic organic molecules in clay inter-layers is known to produce Layer-by-Layer or Langmuir-Blodgett films. Moreover atomistic simulations show that self-organization of organic species in clay interlayers is important. These non-centrosymmetric, chirally active nanofilms may cause clays to act subsequently as chiral amplifiers, concentrating organic material from dilute solution and having different adsorption energetics for D- and L-enantiomers. The additional role of clays in RNA oligomerization already postulated by Ferris and others, together with the need for the organization of amphiphilic molecules and lipids noted by Szostak and others, suggests that such chiral separation by clays in lagoonal environments at normal biological temperatures might also have played a significant role in the origin of biochirality.

  9. Amino acid analyses of Apollo 14 samples.

    Science.gov (United States)

    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.

  10. Unnatural reactive amino acid genetic code additions

    Science.gov (United States)

    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.

  11. Unnatural reactive amino acid genetic code additions

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Amino acids as antioxidants for frying oil

    Science.gov (United States)

    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...

  13. Estimate of Amino Acid Balance in Nutrition

    Institute of Scientific and Technical Information of China (English)

    SunWenzhi

    1995-01-01

    A new chemical index-imbalance degree(IBD),was proposed on the basis of cluster analysis in multivariate statistical analysis to estimate the extent of amino acid balance in protein.The range of IBD is between 0 and 1,successively corresponding to complete baance and entire imbalance for the amino acid profile of a sample.The amino acid increment model of IBD belongs to an asymmetrical maximum-type,and there is a high correlation between IBD and coefficient of variation(CV),The nutritional Value of individual feed can be ranked and clustered according to its IBD;and by calculating the IBD of amixed sample with two or more feedstuffs,it is possible theoretically to predict whether a synergetic phenomenon exists and when an optimal mutual complement can happen.If the conceptive frame of IBD extended,it can be used to study the balance of plement can happen.If the conceptive frame of IBD extended,it can be used to study the balance of nutrients besides amino acids,and is helpful to realize the automatic distinction and selection in diet formulating.

  14. Amino-acid selective experiments on uniformly 13C and 15N labeled proteins by MAS NMR: Filtering of lysines and arginines

    Science.gov (United States)

    Jehle, Stefan; Rehbein, Kristina; Diehl, Anne; van Rossum, Barth-Jan

    2006-12-01

    Amino-acid selective magic-angle spinning (MAS) NMR experiments can aid the assignment of ambiguous cross-peaks in crowded spectra of solid proteins. In particular for larger proteins, data analysis can be hindered by severe resonance overlap. In such cases, filtering techniques may provide a good alternative to site-specific spin-labeling to obtain unambiguous assignments that can serve as starting points in the assignment procedure. In this paper we present a simple pulse sequence that allows selective excitation of arginine and lysine residues. To achieve this, we make use of a combination of specific cross-polarization for selective excitation [M. Baldus, A.T. Petkova, J. Herzfeld, R.G. Griffin, Cross polarization in the tilted frame: assignment and spectral simplification in heteronuclear spin systems, Mol. Phys. 95 (1998) 1197-1207.] and spin diffusion for transfer along the amino-acid side-chain. The selectivity of the filter is demonstrated with the excitation of lysine and arginine side-chain resonances in a uniformly 13C and 15N labeled protein preparation of the α-spectrin SH3 domain. It is shown that the filter can be applied as a building block in a 13C- 13C lysine-only correlation experiment.

  15. Current topics in the biotechnological production of essential amino acids, functional amino acids, and dipeptides.

    Science.gov (United States)

    Mitsuhashi, Satoshi

    2014-04-01

    Amino acids play important roles in both human and animal nutrition and in the maintenance of health. Here, amino acids are classified into three groups: first, essential amino acids, which are essential to nutrition; second, functional amino acids, recently found to be important in the promotion of physiological functions; and third, dipeptides, which are used to resolve problematic features of specific free amino acids, such as their instability or insolubility. This review focusses on recent researches concerning the microbial production of essential amino acids (lysine and methionine), functional amino acids (histidine and ornithine), and a dipeptide (L-alanyl-L-glutamine). PMID:24679256

  16. Stardust, Supernovae and the Chirality of the Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

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

    2011-03-09

    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 thereof on Earth, or could have triggered the chirality that was ultimately achieved for Earth's amino acids.

  17. Supernovae, Neutrinos and the Chirality of Amino Acids

    Directory of Open Access Journals (Sweden)

    Toshitaka Kajino

    2011-05-01

    Full Text Available 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 14N 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.

  18. Supernovae, Neutrinos, and the Chirality of the Amino Acids

    CERN Document Server

    Boyd, R N; Onaka, T

    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 described. The chiral 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. 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.

  19. Identification of a novel system L amino acid transporter structurally distinct from heterodimeric amino acid transporters.

    Science.gov (United States)

    Babu, Ellappan; Kanai, Yoshikatsu; Chairoungdua, Arthit; Kim, Do Kyung; Iribe, Yuji; Tangtrongsup, Sahatchai; Jutabha, Promsuk; Li, Yuewei; Ahmed, Nesar; Sakamoto, Shinichi; Anzai, Naohiko; Nagamori, Seishi; Endou, Hitoshi

    2003-10-31

    A cDNA that encodes a novel Na+-independent neutral amino acid transporter was isolated from FLC4 human hepatocarcinoma cells by expression cloning. When expressed in Xenopus oocytes, the encoded protein designated LAT3 (L-type amino acid transporter 3) transported neutral amino acids such as l-leucine, l-isoleucine, l-valine, and l-phenylalanine. The LAT3-mediated transport was Na+-independent and inhibited by 2-aminobicyclo[2.2.1]heptane-2-carboxylic acid, consistent with the properties of system L. Distinct from already known system L transporters LAT1 and LAT2, which form heterodimeric complex with 4F2 heavy chain, LAT3 was functional by itself in Xenopus oocytes. The deduced amino acid sequence of LAT3 was identical to the gene product of POV1 reported as a prostate cancer-up-regulated gene whose function was not determined, whereas it did not exhibit significant similarity to already identified transporters. The Eadie-Hofstee plots of LAT3-mediated transport were curvilinear, whereas the low affinity component is predominant at physiological plasma amino acid concentration. In addition to amino acid substrates, LAT3 recognized amino acid alcohols. The transport of l-leucine was electroneutral and mediated by a facilitated diffusion. In contrast, l-leucinol, l-valinol, and l-phenylalaninol, which have a net positive charge induced inward currents under voltage clamp, suggesting these compounds are transported by LAT3. LAT3-mediated transport was inhibited by the pretreatment with N-ethylmaleimide, consistent with the property of system L2 originally characterized in hepatocyte primary culture. Based on the substrate selectivity, affinity, and N-ethylmaleimide sensitivity, LAT3 is proposed to be a transporter subserving system L2. LAT3 should denote a new family of organic solute transporters. PMID:12930836

  20. Amino acid properties conserved in molecular evolution.

    Directory of Open Access Journals (Sweden)

    Witold R Rudnicki

    Full Text Available 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.

  1. α-Amino Acid-Isosteric α-Amino Tetrazoles

    NARCIS (Netherlands)

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

    2016-01-01

    The synthesis of all 20 common natural proteinogenic and 4 otherα-amino acid-isosteric α-amino tetrazoles has been accomplished, whereby the carboxyl group is replaced by the isosteric 5-tetrazolyl group. The short process involves the use of the key Ugi tetrazole reaction followed by deprotection c

  2. Amino acid adsorption on mesoporous materials: influence of types of amino acids, modification of mesoporous materials, and solution conditions.

    Science.gov (United States)

    Gao, Qiang; Xu, Wujun; Xu, Yao; Wu, Dong; Sun, Yuhan; Deng, Feng; Shen, Wanling

    2008-02-21

    In order to disclose the dominant interfacial interaction between amino acids and ordered mesoporous materials, the adsorption behaviors of five amino acids on four mesoporous materials were investigated in aqueous solutions with adjustable amino acid concentration, ion strength, and pH. The selected amino acids were acidic amino acid glutamic acid (Glu), basic amino acid arginine (Arg), and neutral amino acids phenylalanine (Phe), leucine (Leu), and alanine (Ala), and the selected mesoporous materials were SBA-15, Al-SBA-15, CH3(10%)-SBA-15, and CH3(20%)-SBA-15. The adsorption capacities of Glu and Arg were strongly dependent on pH and surface charge of the mesoporous adsorbent. The adsorption of Phe showed pH insensitivity but depended on the surface organic functionalization of mesoporous adsorbent. On the basis of the theoretical analysis about the interaction between amino acid and adsorbent, such a remarkable difference was attributed to the different nature of the interaction between amino acid and adsorbent. Arg could be readily adsorbed on the surface of SBA-15, especially Al-SBA-15, under appropriate pH in which the electrostatic interaction was predominant. The driving force of Phe adsorption on mesoporous adsorbent mainly came from the hydrophobic interaction. Therefore, the adsorption capability of Arg decreased with increasing ion strength of solution, while the adsorption capability of Phe increased with the increasing degree of CH3 functionalization on SBA-15. For neutral amino acid Phe, Ala, and Leu, the adsorption capability increased with the increase of the length of their side chains, which was another evidence of hydrophobic effect. Thus, all the adsorption of amino acids on mesoporous silica materials can be decided by the combined influence of two fundamental interactions: electrostatic attraction and hydrophobic effect.

  3. Indigenous amino acids in primitive CR meteorites

    CERN Document Server

    Martins, Z; Orzechowska, G E; Fogel, M L; Ehrenfreund, P

    2008-01-01

    CR meteorites are among the most primitive meteorites. In this paper, 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. EET92042, GRA95229 and GRO95577 were analyzed for their amino acid content using high performance liquid chromatography with UV fluorescence detection (HPLC-FD) and gas chromatographymass spectrometry (GC-MS). Our data show that EET92042 and GRA95229 are the most amino acid-rich chondrites ever analyzed, with total amino acid concentrations ranging from 180 parts-per-million (ppm) to 249 ppm. GRO95577, however, is depleted in amino acids. The most abundant amino acids present in the EET92042 and GRA95229 meteorites are the alpha-amino acids glycine, isovaline, alpha-aminoisobutyric acid (alpha-AIB), and alanine, with delta13C values ranging from +31.6per mil to +50.5per mil. The carbon isotope results together with racemic enantiomeric ratios determined for most amino acids strongly i...

  4. Immune escape mutants of Highly Pathogenic Avian Influenza H5N1 selected using polyclonal sera: identification of key amino acids in the HA protein.

    Directory of Open Access Journals (Sweden)

    Ioannis Sitaras

    Full Text Available Evolution of Avian Influenza (AI viruses--especially of the Highly Pathogenic Avian Influenza (HPAI H5N1 subtype--is a major issue for the poultry industry. HPAI H5N1 epidemics are associated with huge economic losses and are sometimes connected to human morbidity and mortality. Vaccination (either as a preventive measure or as a means to control outbreaks is an approach that splits the scientific community, due to the risk of it being a potential driving force in HPAI evolution through the selection of mutants able to escape vaccination-induced immunity. It is therefore essential to study how mutations are selected due to immune pressure. To this effect, we performed an in vitro selection of mutants from HPAI A/turkey/Turkey/1/05 (H5N1, using immune pressure from homologous polyclonal sera. After 42 rounds of selection, we identified 5 amino acid substitutions in the Haemagglutinin (HA protein, most of which were located in areas of antigenic importance and suspected to be prone to selection pressure. We report that most of the mutations took place early in the selection process. Finally, our antigenic cartography studies showed that the antigenic distance between the selected isolates and their parent strain increased with passage number.

  5. α-Amino Acid-Isosteric α-Amino Tetrazoles.

    Science.gov (United States)

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

    2016-02-24

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

  6. Amino acid composition of some Mexican foods.

    Science.gov (United States)

    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.

  7. Adaptive amino acid composition in collagens of parasitic nematodes.

    Science.gov (United States)

    Hughes, Austin L

    2015-04-01

    Amino acid composition was analyzed in the glycine-rich repeat region of 306 collagens belonging to three major families of collagens from both parasitic and free-living nematodes. The collagens of parasitic species showed a tendency toward decreased usage of the hydrophilic residues A, D, and Q and increased usage of the hydrophobic resides I, L, and M; and this trend was seen in parasitic species of both the order Rhabdita and the order Spirurida. The amino acid composition of collagens of parasitic Rhabdita thus tended to resemble those of Spirurida more than that of free-living Rhabdita, suggesting an association between amino acid composition and a parasitic lifestyle. Computer predictions suggested that the more hydrophobic amino acid composition was associated with a reduction of the propensity towards B-cell epitope formation, suggesting that evasion of host immune responses may be a major selective factor responsible for the parasite-specific trend in collagen amino acid composition.

  8. Research for amino acids in lunar samples.

    Science.gov (United States)

    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.

  9. Synthesis of Chiral Amino Cyclic Phosphoric Acids

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    Chirai amino cyclic phosphoric acids, 5-amino-2-hydroxy-4- (4-nitrophenyl)-l, 3,2-dioxaphospho- rinane 2-oxide and 2-hydroxy-4- (4-methylsulfonylphenyl)-5-phthalimido-1,3,2-dioxaphos phorinane 2-oxide are synthesized in good over yields (64. 2% and 72. 8% respectively) from 2-amino-l-aryl-l,3-propanediols. The different reaction conditions are necessary in hydrolysis reactions of amino cyclic phosphonyl chlorides.

  10. Plasma amino acid relationships during parenteral nutrition.

    Science.gov (United States)

    Wells, F E; Smits, B J

    1980-01-01

    The plasma amino acidfs of 17 patients were studied before and during total parenteral nutrition (TPN). The amino acid (AA) pattern changed similarly for all patients. The AA concentration changes relative to preinfusion (PAER) were the most informative index of change. Two groups of AA were defined, the "branched chain" group (five amino acids) and the "hepatic" group (four amino acids) based on the correlation of PAER values. Comparison of PAER values with the ratio of AA intake to requirement indicated that the requirements of the sick patients were more similar to those of children than those of healthy adults.

  11. Amino acid content of selected plant, algae and insect species: a search for alternative protein sources for use in pet foods*

    OpenAIRE

    McCusker, Sarah; Buff, Preston R.; Yu, Zengshou; Fascetti, Andrea J.

    2014-01-01

    In response to global economic duress and heightened consumer awareness of nutrition and health, sustainable and natural ingredients are in demand. Identification of alternative sources of nitrogen and amino acids, including taurine, may help meet dietary requirements while fostering sustainability and natural feeding approaches. Twenty plants, eighteen marine algae and five insect species were analysed. All samples were freeze-dried, hydrolysed and filtered prior to amino acid analysis. Samp...

  12. Microbial production of natural poly amino acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Three kinds of poly amino acids, poly-γ-glutamic acid, poly(ε-L-lysine) and multi-L-arginyl-poly (L-aspartic acid) can be synthesized by enzymatic process independently from ribosomal protein biosynthesis pathways in microorganism. These biosynthesized polymers have attracted more and more attentions because of their unique properties and various applications. In this review, the current knowledge on the biosynthesis, biodegradations and applications of these three poly amino acids are summarized.

  13. Poly(3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)) (PEDOT-PANS) film modified glassy carbon electrode for selective detection of dopamine in the presence of ascorbic acid and uric acid

    International Nuclear Information System (INIS)

    Poly(3,4-ethylenedioxythiophene-co-(5-amino-2-naphthalenesulfonic acid)) (PEDOT-PANS) film modified glassy carbon electrode was prepared by electrochemical polymerization technique. The properties of modified electrode was studied. It was found that the electrochemical properties of modified electrode was very much dependent on the experimental conditions, such as monomer oxidation potential and pH. The modified electrode surface was characterized by scanning electron microscopy (SEM). The PEDOT-PANS film modified electrode shows electrocatalytic activity toward oxidation of dopamine (DA) in acetate buffer solution (pH 5.0) and results in a marked enhancement of the current response. The linear sweep voltammetric (LSV) peak heights are linear with DA concentration from 2 x 10-6 to 1 x 10-5 M. The detection limit is 5 x 10-7 M. More over, the interferences of ascorbic acid (AA) and uric acid (UA) were effectively diminished. This work provides a simple and easy approach for selective determination of dopamine in the presence of ascorbic acid and uric acid

  14. Human Protein and Amino Acid Requirements.

    Science.gov (United States)

    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. PMID:26796095

  15. 6th Amino Acid Assessment Workshop

    Science.gov (United States)

    The focus of the 6th workshop is on lysine, arginine, and related amino acids. Functions, metabolic pathways, clinical uses, and upper tolerance intakes are emphasized in the articles that follow. Lysine is arguably the most deficient amino acid in the food supply of countries where poverty exists, ...

  16. Crystalline amino acids and nitrogen emission

    NARCIS (Netherlands)

    Verstegen, M.W.A.; Jongbloed, A.W.

    2003-01-01

    Reductions in dietary protein level and supplementation with certain crystalline amino acids is a well-established method of formulating diets to achieve a more ideal amino acid pattern and to reduce nitrogen excretion. Up to 35% reduction in nitrogen excretion may be achieved by supplementing pig d

  17. The Apollo Program and Amino Acids

    Science.gov (United States)

    Fox, Sidney W.

    1973-01-01

    Discusses the determination of hydrolyzable amino acid precursors and a group of six amino acids in the returned lunar samples of the Apollo programs. Indicates that molecular evolution is arrested at the precursor stage on the Moon because of lack of water. (CC)

  18. Determining important regulatory relations of amino acids from dynamic network analysis of plasma amino acids.

    Science.gov (United States)

    Shikata, Nahoko; Maki, Yukihiro; Nakatsui, Masahiko; Mori, Masato; Noguchi, Yasushi; Yoshida, Shintaro; Takahashi, Michio; Kondo, Nobuo; Okamoto, Masahiro

    2010-01-01

    The changes in the concentrations of plasma amino acids do not always follow the flow-based metabolic pathway network. We have previously shown that there is a control-based network structure among plasma amino acids besides the metabolic pathway map. Based on this network structure, in this study, we performed dynamic analysis using time-course data of the plasma samples of rats fed single essential amino acid deficient diet. Using S-system model (conceptual mathematical model represented by power-law formalism), we inferred the dynamic network structure which reproduces the actual time-courses within the error allowance of 13.17%. By performing sensitivity analysis, three of the most dominant relations in this network were selected; the control paths from leucine to valine, from methionine to threonine, and from leucine to isoleucine. This result is in good agreement with the biological knowledge regarding branched-chain amino acids, and suggests the biological importance of the effect from methionine to threonine.

  19. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Alkyl amino substituted triazine amino... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo... substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  20. Effect of Selectively Introducing Arginine and D-Amino Acids on the Antimicrobial Activity and Salt Sensitivity in Analogs of Human Beta-Defensins

    Science.gov (United States)

    Olli, Sudar; Rangaraj, Nandini; Nagaraj, Ramakrishnan

    2013-01-01

    We have examined the antimicrobial activity of C-terminal analogs of human β-defensins HBD-1and-3 wherein lysines have been selectively replaced by L- and D-arginines and L-isoleucine substituted with its D-enantiomer. The analogs exhibited antibacterial and antifungal activities. Physiological concentration of NaCl did not attenuate the activity of the peptides against Gram-negative bacteria considerably, while some attenuation of activity was observed against S. aureus. Variable attenuation of activity was observed in the presence of Ca2+ and Mg2+. Introduction of D-amino acids abrogated the need for a disulfide bridge for exhibiting activity. Confocal images of carboxyfluorescein (CF) labeled peptides indicated initial localization on the membrane and subsequent translocation into the cell. Analogs corresponding to cationic rich segments of human defensins substituted with L- and D-arginine, could be attractive candidates for development as future therapeutic drugs. PMID:24086767

  1. Data for amino acid alignment of Japanese stingray melanocortin receptors with other gnathostome melanocortin receptor sequences, and the ligand selectivity of Japanese stingray melanocortin receptors

    Directory of Open Access Journals (Sweden)

    Akiyoshi Takahashi

    2016-06-01

    Full Text Available This article contains structure and pharmacological characteristics of melanocortin receptors (MCRs related to research published in “Characterization of melanocortin receptors from stingray Dasyatis akajei, a cartilaginous fish” (Takahashi et al., 2016 [1]. The amino acid sequences of the stingray, D. akajei, MC1R, MC2R, MC3R, MC4R, and MC5R were aligned with the corresponding melanocortin receptor sequences from the elephant shark, Callorhinchus milii, the dogfish, Squalus acanthias, the goldfish, Carassius auratus, and the mouse, Mus musculus. These alignments provide the basis for phylogenetic analysis of these gnathostome melanocortin receptor sequences. In addition, the Japanese stingray melanocortin receptors were separately expressed in Chinese Hamster Ovary cells, and stimulated with stingray ACTH, α-MSH, β-MSH, γ-MSH, δ-MSH, and β-endorphin. The dose response curves reveal the order of ligand selectivity for each stingray MCR.

  2. Synthesis of β-Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    Zhao Yonghua; Ma Zhihua; Jiang Nan; Wang Jianbo

    2004-01-01

    In recent years, β-amino acids and their derivatives have attracted considerable attention due to their occurrence in biologically active natural products, such as dolastatins,cyclohexylnorstatine and Taxol. β-Amino acids also find application in the synthesis of β-lactams,piperidines, indolizidines. Moreover, the peptides consisting of β-amino acids, the so-called β-peptides, have been extensively studied recently. Consequently, considerable efforts have been directed to the synthesis of β-amino acids and their derivatives1. In particular, stereoselective synthesis of β-amino acids has been a challenging project, and there are only limited methods available. In this presentation, we report our efforts in this area.

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

    Science.gov (United States)

    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.

  4. Noninvasive tagging of proteins with an inorganic chromophore. Selectivity of chloro(terpyridine)platinum(II) toward amino acids, peptides, and cytochromes c

    Energy Technology Data Exchange (ETDEWEB)

    Brothers, H.M. II; Kostic, N.M.

    1988-05-18

    The complex (Pt(trpy)Cl)/sup +/ exhibits unexpected selectivity toward amino acid side chains in cytochromes c from Candida krusei and bakers' yeast. Although kinetic studies with amino acids and peptides as entering ligands prove this complex to be completely selective toward thiol over imidazole, His-33 and His-39 residues (in both proteins) are labeled with greater yields than the Cys-102 residue (in the bakers' yeast protein). The binding sites are determined by peptide mapping and other methods. The Pt(trpy)/sup 2+/ tags are stable, and the protein derivatives are separated by cation-exchange chromatography. The (Pt(trpy)His)/sup 2+/ and (Pt(trpy)Cys)/sup +/ chromophores are easily detected and quantitated owing to their characteristic and strong UV-vis bands. Spectroscopic and electrochemical measurements show that labeling with the new reagent does not alter the structural and redox properties of the cytochromes c. The unexpected outcome of the protein labeling indicates that, contrary to the common assumption, Cys-102 is not exposed at the protein surface. Modification of this residue with various organic reagents and dimerization of the protein must be accompanied by a perturbation of the conformation, which makes Cys-102 accessible to the reagent or to another molecule of the protein. These predictions from the labeling study are confirmed subsequently by the crystallographic study of the iso-1 cytochrome c from bakers' yeast. The inorganic complex (Pt(trpy)Cl)/sup +/ differs from the other reagents for protein modification by its noninvasiveness, a property that may well render it useful as a probe of the protein surface. 59 refs., 2 figs., 4 tabs.

  5. Genetics of Amino Acid Taste and Appetite.

    Science.gov (United States)

    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. PMID:27422518

  6. Amino acid decarboxylations produced by lipid-derived reactive carbonyls in amino acid mixtures.

    Science.gov (United States)

    Hidalgo, Francisco J; León, M Mercedes; Zamora, Rosario

    2016-10-15

    The formation of 2-phenylethylamine and phenylacetaldehyde in mixtures of phenylalanine, a lipid oxidation product, and a second amino acid was studied to determine the role of the second amino acid in the degradation of phenylalanine produced by lipid-derived reactive carbonyls. The presence of the second amino acid usually increased the formation of the amine and reduced the formation of the Strecker aldehyde. The reasons for this behaviour seem to be related to the α-amino group and the other functional groups (mainly amino or similar groups) present in the side-chain of the amino acid. These groups are suggested to modify the lipid-derived reactive carbonyl but not the reaction mechanism because the Ea of formation of both 2-phenylethylamine and phenylacetaldehyde remained unchanged in all studied systems. All these results suggest that the amine/aldehyde ratio obtained by amino acid degradation can be modified by adding free amino acids during food formulation. PMID:27173560

  7. Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

    DEFF Research Database (Denmark)

    Conti, Paola; De Amici, Marco; Joppolo Di Ventimiglia, Samuele;

    2003-01-01

    Bicyclic acidic amino acids (+/-)-6 and (+/-)-7, which are conformationally constrained homologues of glutamic acid, were prepared via a strategy based on a 1,3-dipolar cycloaddition. The new amino acids were tested toward ionotropic and metabotropic glutamate receptor subtypes; both of them...

  8. Amino acid analogs for tumor imaging

    Science.gov (United States)

    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.

  9. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Mark M. (Atlanta, GA); Shoup, Timothy (Decatur, GA)

    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.

  10. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    Goodman, Mark M. (Atlanta, GA); Shoup, Timothy (Decatur, GA)

    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.

  11. Amino acid analogs for tumor imaging

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. Amino Acid Stability in the Early Oceans

    Science.gov (United States)

    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.

  13. Distribution of Amino Acids in Lunar Regolith

    Science.gov (United States)

    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.

  14. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    Science.gov (United States)

    Lomstein, Bente Aa.; Jørgensen, Bo B.; Schubert, Carsten J.; Niggemann, Jutta

    2006-06-01

    increased sediment depth and age (up to 288-year-old) reaching up to 59%. Independent estimates based on D-amino acid concentrations in selected laboratory strains, bacterial counts and the sedimentary concentrations of D-amino acids indicate that a large fraction of the measured D-amino acids (>47 to >97%) originated from cell wall residues rather than from enumerated cells.

  15. Amino Acid Degradation after Meteoritic Impact Simulation

    Science.gov (United States)

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

    2008-01-01

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

  16. Classification and identification of amino acids based on THz spectroscopy

    Science.gov (United States)

    Huang, Ping J.; Ma, Ye H.; Li, Xian; Hou, Di B.; Cai, Jin H.; Zhang, Guang X.

    2015-11-01

    Amino acids are important nutrient substances for life, and many of them have several isomerides, while only L-type amino acids can be absorbed by body as nutrients. So it is certain worth to accurately classify and identify amino acids. In this paper, terahertz time-domain spectroscopy (THz-TDS) was used to detect isomers of various amino acids to obtain their absorption spectra, and their spectral characteristics were analyzed and compared. Results show that not all isomerides of amino acids have unique spectral characteristics, causing the difficulty of classification and identification. To solve this problem, partial least squares discriminant analysis (PLS-DA), firstly, was performed on extracting principal component of THz spectroscopy and classifying amino acids. Moreover, variable selection (VS) was employed to optimize spectral interval of feature extraction to improve analysis effect. As a result, the optimal classification model was determined and most samples can be accurately classified. Secondly, for each class of amino acids, PLS-DA combined with VS was also applied to identify isomerides. This work provides a suggestion for material classification and identification with THz spectroscopy.

  17. Selection and Identification of Critical Amino Acids in Epitope 187-202 ofPen a1%Pen a1抗原表位187-202关键氨基酸的筛选和鉴定

    Institute of Scientific and Technical Information of China (English)

    牟慧; 高美须; 潘家荣; 支玉香; 赵杰; 刘超超; 李树锦; 赵鑫

    2014-01-01

    Objective Pen a1 is the major allergen in shrimp, and the sensitization mechanism is related with epitopes. The epitope (187-202) of Pen a1 was chosen as the research material, the amino acids’ frequency of occurrence and their conservative property were analyzed, the mutants were synthesized and the IgE capacity of the mutants were analyzed. The critical amino acids of the epitope of Pen a1 were screened out in order to study the shrimp sensitization mechanism and provide a theoretical basis for desensitization.[Method] The amino acid composition and frequency of occurrence in Pen a1, all epitopes and the studied epitope were analyzed using MEGA5, and the amino acids with the highest frequency were chosen. And then the amino acids of tropomyosin in all the allergenic foods in SDAP were also investigated, and the high conservative amino acids were chosen. The common amino acids in the results of both methods were considered to be the potential critical amino acids. Then these amino acids were substituted by alanine, the wild-type peptide and the mutant peptides were then synthesized with solid phase synthesis method. The tested serum was prepared by immuning New Zealand rabbits with wild-type peptide. The capacity of IgE-binding between the wild-type peptide and the mutants were compared with iELISA and competitive Dot-blot methods. The mutant peptides whose capacity of IgE-binding showed a dramatic decline were selected, and the replaced amino acids of the peptides were recognized as the critical amino acids.[Result] The amino acids of glutamic acid (E), leucine (L), arginine (R), glutamine (Q), valine (V), serine (S), aspartic acid (D) were found with higher frequency occurrence in epitope than inPen a1, and were considered as the active amino acids. E, V, L in epitope (187-202) were found with higher frequency occurrence, and were inferred to be the potential critical amino acids of studied epitope. The multiple sequence alignment of tropomyosin from

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

    Science.gov (United States)

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

    2016-01-25

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

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

    Science.gov (United States)

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

    2016-01-25

    Amino acids (AAs) obtained from the hydrolysis of biomass-derived proteins are interesting feedstocks for the chemical industry. They can be prepared from the byproduct of biofuel production and agricultural wastes. They are rich in functionalities needed in petrochemicals, providing the opportunity to save energy, reagents, and process steps. However, their separation is required before they can be applied for further applications. Electrodialysis (ED) is a promising separation method, but its efficiency needs to be improved when separating AAs with similar isoelectric points. Thus, specific conversions are required to form product with different charges. Here we studied the enzymatic conversions which can be used as a means to aid the ED separation of neutral AAs. A model mixture containing L-serine, L-phenylalanine and L-methionine was used. The reactions of L-serine decarboxylase and L-phenylalanine ammonia-lyase were employed to specifically convert serine and phenylalanine into ethanolamine and trans-cinnamic acid. At the isoelectric point of methionine (pH 5.74), the charge of ethanolamine and trans-cinnamic acid are +1 and -1, therefore facilitating potential separation into three different streams by electrodialysis. Here the enzyme kinetics, specificity, inhibition and the operational stabilities were studied, showing that both enzymes can be applied simultaneously to aid the ED separation of neutral AAs. PMID:25976628

  20. Effect of amino acids and amino acid derivatives on crystallization of hemoglobin and ribonuclease A

    Energy Technology Data Exchange (ETDEWEB)

    Ito, Len, E-mail: len@ksc.kwansei.ac.jp; Kobayashi, Toyoaki [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan); Shiraki, Kentaro [Institute of Applied Physics, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8573 (Japan); Yamaguchi, Hiroshi [School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337 (Japan)

    2008-05-01

    The effect of the addition of amino acids and amino acid derivatives on the crystallization of hemoglobin and ribonuclease A has been evaluated. The results showed that certain types of additives expand the concentration conditions in which crystals are formed. Determination of the appropriate conditions for protein crystallization remains a highly empirical process. Preventing protein aggregation is necessary for the formation of single crystals under aggregation-prone solution conditions. Because many amino acids and amino acid derivatives offer a unique combination of solubility and stabilizing properties, they open new avenues into the field of protein aggregation research. The use of amino acids and amino acid derivatives can potentially influence processes such as heat treatment and refolding reactions. The effect of the addition of several amino acids, such as lysine, and several amino acid derivatives, such as glycine ethyl ester and glycine amide, on the crystallization of equine hemoglobin and bovine pancreatic ribonuclease A has been examined. The addition of these amino acids and amino acid derivatives expanded the range of precipitant concentration in which crystals formed without aggregation. The addition of such additives appears to promote the crystallization of proteins.

  1. D-amino acids trigger biofilm disassembly.

    Science.gov (United States)

    Kolodkin-Gal, Ilana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard

    2010-04-30

    Bacteria form communities known as biofilms, which disassemble over time. In our studies outlined here, we found that, before biofilm disassembly, Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine, and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofilms in the presence of D-amino acids contained alterations in a protein (YqxM) required for the formation and anchoring of the fibers to the cell. D-amino acids also prevented biofilm formation by Staphylococcus aureus and Pseudomonas aeruginosa. D-amino acids are produced by many bacteria and, thus, may be a widespread signal for biofilm disassembly. PMID:20431016

  2. AMINO ACIDS APPLICATION TO CREATE OF NANOSTRUCTURES

    Directory of Open Access Journals (Sweden)

    I. S. Chekman

    2014-12-01

    Full Text Available Review is devoted to the amino acids that could be used for nanostructures creation. The investigation of corresponding properties of amino acids is essential for their role definition in creation of nanomedicines. However, amino acid studying as components of nanostructures is insufficient. Study of nanoparticles for medicines creation was initiated by the development of nanotechnology. Amino acids in complexes with the nanoparticles of organic and inorganic nature play an important role for medicines targeting in pathological process. They could reduce toxicity of the nanomaterials used in nanomedicine and are used for creation of biosensors, lab-on-chip and therefore they are a promising material for synthesis of new nanodrugs and diagnostic tools.

  3. Amino Acid Intake in Preterm Infants.

    Science.gov (United States)

    Burattini, Ilaria; Bellagamba, Maria Paola; D''Ascenzo, Rita; Biagetti, Chiara; Carnielli, Virgilio Paolo

    2016-01-01

    A large proportion of extremely low-birth-weight infants requires parenteral nutrition for variable lengths of time. Amino acids are the key ingredients of parenteral nutrition. The goal of appropriate amino acid administration is to promote anabolism and normal cellular development in order to limit the incidence of postnatal growth restriction, which is associated with neurodevelopmental delays. The benefits of early amino acid commencement soon after birth are compelling, especially on nitrogen balance, while long-term outcome studies are lacking. Amino acid administration at 2.5 g/kg per day has been shown to be superior to lower intakes; however, the benefits of intakes above 2.5 g/kg per day remain controversial. PMID:27336474

  4. A set of engineered Escherichia coli expression strains for selective isotope and reactivity labeling of amino acid side chains and flavin cofactors.

    Directory of Open Access Journals (Sweden)

    Jennifer Mehlhorn

    Full Text Available Biological reactions are facilitated by delicate molecular interactions between proteins, cofactors and substrates. To study and understand their dynamic interactions researchers have to take great care not to influence or distort the object of study. As a non-invasive alternative to a site-directed mutagenesis approach, selective isotope labeling in combination with vibrational spectroscopy may be employed to directly identify structural transitions in wild type proteins. Here we present a set of customized Escherichia coli expression strains, suitable for replacing both the flavin cofactor and/or selective amino acids with isotope enriched or chemically modified substrates. For flavin labeling we report optimized auxotrophic strains with significantly enhanced flavin uptake properties. Labeled protein biosynthesis using these strains was achieved in optimized cultivation procedures using high cell density fermentation. Finally, we demonstrate how this approach is used for a clear assignment of vibrational spectroscopic difference signals of apoprotein and cofactor of a flavin containing photoreceptor of the BLUF (Blue Light receptors Using FAD family.

  5. Neutron inelastic scattering from amino acids

    International Nuclear Information System (INIS)

    Neutron incoherent inelastic scattering technique is used for studying the extensive hydrogen bonding that connects the molecules together and gives the structure cohesion in three dimension in amino acids. Results on five amino acids namely, α-glycine, DL-alanine, L-valine, L-tyrosine and L-phenyl-alanine having different side groups are reported and compared with those from other methods. The main emphasis is on the torsional motions of NH3+ and CH3 groups. (K.B.)

  6. Genetically encoded fluorescent coumarin amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jiangyun (San Diego, CA); Xie, Jianming (San Diego, CA); Schultz, Peter G. (La Jolla, CA)

    2012-06-05

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

  7. Genetically encoded fluorescent coumarin amino acids

    Science.gov (United States)

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

    2010-10-05

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

  8. Direct influence of C-terminally substituted amino acids in the Dmt-Tic pharmacophore on delta-opioid receptor selectivity and antagonism.

    Science.gov (United States)

    Balboni, Gianfranco; Salvadori, Severo; Guerrini, Remo; Negri, Lucia; Giannini, Elisa; Bryant, Sharon D; Jinsmaa, Yunden; Lazarus, Lawrence H

    2004-07-29

    A series of 17 analogues were developed on the basis of the general formula H-Dmt-Tic-NH-CH(R)-R' (denotes chirality; R = charged, neutral, or aromatic functional group; R' = -OH or -NH(2)). These compounds were designed to test the following hypothesis: the physicochemical properties of third-residue substitutions C-terminal to Tic in the Dmt-Tic pharmacophore modify delta-opioid receptor selectivity and delta-opioid receptor antagonism through enhanced interactions with the mu-opioid receptor. The data substantiate the following conclusions: (i) all compounds had high receptor affinity [K(i)(delta) = 0.034-1.1 nM], while that for the mu-opioid receptor fluctuated by orders of magnitude [K(i)(mu) = 15.1-3966 nM]; (ii) delta-opioid receptor selectivity [K(i)(mu)/K(i)(delta)] declined 1000-fold from 22,600 to 21; (iii) a C-terminal carboxyl group enhanced selectivity but only as a consequence of the specific residue; (iv) amidated, positive charged residues [Lys-NH(2) (6), Arg-NH(2) (7)], and a negatively charged aromatic residue [Trp-OH (11)] enhanced mu-opioid affinity [K(i)(mu) = 17.0, 15.1, and 15.7 nM, respectively], while Gly-NH(2) (8), Ser-NH(2) (10), and His-OH (12) were nearly one-tenth as active; and (v) D-isomers exhibited mixed effects on mu-opioid receptor affinity (2' 1 microM) except H-Dmt-Tic-Glu-NH(2) (3), which was a partial delta-opioid receptor agonist (IC(50) = 2.5 nM). Thus, these C-terminally extended analogues indicated that an amino acid residue containing a single charge, amino or guanidino functionality, or aromatic group substantially altered the delta-opioid receptor activity profile (selectivity and antagonism) of the Dmt-Tic pharmacophore, which suggests that the C-terminal constituent plays a major role in determining opioid receptor activity as an "address domain".

  9. Amino Acid Patterns around Disulfide Bonds

    Directory of Open Access Journals (Sweden)

    Brett Drury

    2010-11-01

    Full Text Available Disulfide bonds provide an inexhaustible source of information on molecular evolution and biological specificity. In this work, we described the amino acid composition around disulfide bonds in a set of disulfide-rich proteins using appropriate descriptors, based on ANOVA (for all twenty natural amino acids or classes of amino acids clustered according to their chemical similarities and Scheffé (for the disulfide-rich proteins superfamilies statistics. We found that weakly hydrophilic and aromatic amino acids are quite abundant in the regions around disulfide bonds, contrary to aliphatic and hydrophobic amino acids. The density distributions (as a function of the distance to the center of the disulfide bonds for all defined entities presented an overall unimodal behavior: the densities are null at short distances, have maxima at intermediate distances and decrease for long distances. In the end, the amino acid environment around the disulfide bonds was found to be different for different superfamilies, allowing the clustering of proteins in a biologically relevant way, suggesting that this type of chemical information might be used as a tool to assess the relationship between very divergent sets of disulfide-rich proteins.

  10. Effects of Exogenous Amino Acids on the Contents of Amino Acids in Tobacco Leaves

    Institute of Scientific and Technical Information of China (English)

    WU Xue-ping; LIU Guo-shun; ZHU Kai; PENG Sa; GUO Qiao-yan

    2005-01-01

    The effect of three amino acids on the growth of flue-cured tobacco was studied with water culture. The results showed that the three amino acids improved the growth of flue-cured tobacco and increased the contents of chlorophyll a,chlorophyll b and carotenoid in tobacco. At the same time, the activities of NR (nitrate reductase), INV(invertase) and root growth activity were also significantly enhanced. The exogenous glutamic, aspartate and phenylalanine all increased the amino acid contents of tobacco leaves. Of these three amino acids, glutamic had the greatest effect, the next was aspartate,and phenylalanine had the least effect. These three amino acids all had significantly increased the accumulation of amino acids in the leaves of individual plants of tobacco; and the magnitude of accumulation indicated aspartate > glutamic >phenylalanine.

  11. Selective photoreduction of nitrobenzene to aniline on TiO{sub 2} nanoparticles modified with amino acid

    Energy Technology Data Exchange (ETDEWEB)

    Huang Heyong; Zhou Jiahong [Key Lab of Biofunctional Materials of Jiangsu Province, Analysis and Testing Center, Nanjing Normal University, Nanjing 210097 (China); Department of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097 (China); Liu Hailong [Department of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097 (China); Zhou Yanhuai, E-mail: zhouyanhuai@njnu.edu.cn [Department of Physical Science and Technology, Nanjing Normal University, Nanjing 210097 (China); Feng Yuying, E-mail: yyfeng3@163.com [Key Lab of Biofunctional Materials of Jiangsu Province, Analysis and Testing Center, Nanjing Normal University, Nanjing 210097 (China) and Department of Chemistry and Environmental Science, Nanjing Normal University, Nanjing 210097 (China)

    2010-06-15

    The photoreduction of nitrobenzene (NB) on TiO{sub 2} nanoparticles modified with asparagine (Asp), serine (Ser), phenylalanine (Phe) and tyrosine (Tyr), which were found to bind to TiO{sub 2} via carboxyl group, have been investigated under high-pressure mercury irradiation. Modification of TiO{sub 2} with Asp, Ser and Phe resulted in enhanced photocatalytic degradation rate of NB and high selective activity to aniline (AN) compared to using bare TiO{sub 2}. Furthermore, NB degradation followed a reductive approach over Asp, Ser, Phe-modified TiO{sub 2} whether in additional of methanol or not. The result indicates that modification of TiO{sub 2} with electron-donating groups is an effective way to enhance photoreduction of nitroaromatic compounds.

  12. Amino acid survival in large cometary impacts

    Science.gov (United States)

    Pierazzo, E.; Chyba, C. F.

    1999-11-01

    A significant fraction of the Earth's prebiotic volatile inventory may have been delivered by asteroidal and cometary impacts during the period of heavy bombardment. The realization that comets are particularly rich in organic material seemed to strengthen this suggestion. Previous modeling studies, however, indicated that most organics would be entirely destroyed in large comet and asteroid impacts. The availability of new kinetic parameters for the thermal degradation of amino acids in the solid phase made it possible to readdress this question. We present the results of new high-resolution hydrocode simulations of asteroid and comet impact coupled with recent experimental data for amino acid pyrolysis in the solid phase. Differences due to impact velocity as well as projectile material have been investigated. Effects of angle of impacts were also addressed. The results suggest that some amino acids would survive the shock heating of large (kilometer-radius) cometary impacts. At the time of the origins of life on Earth, the steady-state oceanic concentration of certain amino acids (like aspartic and glutamic acid) delivered by comets could have equaled or substantially exceeded that due to Miller-Urey synthesis in a carbon dioxide-rich atmosphere. Furthermore, in the unlikely case of a grazing impact (impact angle around 5 degrees from the horizontal) an amount of some amino acids comparable to that due to the background steady-state production or delivery would be delivered to the early Earth.

  13. Expression of heteromeric amino acid transporters along the murine intestine.

    Science.gov (United States)

    Dave, Mital H; Schulz, Nicole; Zecevic, Marija; Wagner, Carsten A; Verrey, Francois

    2004-07-15

    Members of the new heterodimeric amino acid transporter family are composed of two subunits, a catalytic multitransmembrane spanning protein (light chain) and a type II glycoprotein (heavy chain). These transporters function as exchangers and thereby extend the transmembrane amino acid transport selectivity to specific amino acids. The heavy chain rBAT associates with the light chain b degrees (,+)AT to form a cystine and cationic amino acid transporter. The other heavy chain, 4F2hc, can interact with seven different light chains to form various transporters corresponding to systems L, y(+)L, asc or x(-)(c). The importance of some of these transporters in intestinal and renal (re)absorption of amino acids is highlighted by the fact that mutations in either the rBAT or b degrees (,+)AT subunit result in cystinuria whereas a defect in the y(+)-LAT1 light chain causes lysinuric protein intolerance. Here we investigated the localization of these transporters in intestine since both diseases are also characterized by altered intestinal amino acid absorption. Real time PCR showed organ-specific expression patterns for all transporter subunit mRNAs along the intestine and Western blotting confirmed these findings on the protein level. Immunohistochemistry demonstrated basolateral coexpression of 4F2hc, LAT2 and y(+)-LAT1 in stomach and small intestine, whereas rBAT and b degrees (,+)AT were found colocalizing on the apical side of small intestine epithelium. In stomach, 4F2hc and LAT2 were localized in H(+)/K(+)-ATPase-expressing parietal cells. The abundant expression of several members of the heterodimeric transporter family along the murine small intestine suggests their involvement in amino acids absorption. Furthermore, strong expression of rBAT, b degrees (,+)AT and y(+)-LAT1 in the small intestine explains the reduced intestinal absorption of some amino acid in patients with cystinuria or lysinuric protein intolerance.

  14. Amino acid efflux in the isolated perfused rat pancreas: trans-stimulation by extracellular amino acids.

    Science.gov (United States)

    Mann, G E; Norman, P S; Smith, I C

    1989-01-01

    1. Epithelial uptake and efflux of the non-metabolized system A analogue 2-methylaminoisobutyric acid (MeAIB) and L-serine were studied in the isolated perfused rat pancreas using a dual tracer loading and wash-out technique. Uptakes of 2-[14C]MeAIB and L-[3H]serine were measured relative to D-[3H or 14C]mannitol (extracellular tracer) during a 20 min cell loading period. Maximal uptake for MeAIB (34 +/- 2%, n = 6) occurred within 2-3 min and decreased to 14 +/- 2% after 20 min tracer loading. Uptake for L-serine reached a maximum (62 +/- 4%, n = 7) within 1 min and decreased to 19 +/- 2% after 20 min tracer loading. 2. When tracer wash-out was monitored during subsequent perfusion of the preloaded pancreas with an isotope-free solution, D-mannitol predominantly cleared from a fast exchanging compartment (0.54 +/- 0.05 ml g-1, n = 9) with a time constant (Tfast) of 0.68 +/- 0.04 min. Although MeAIB and L-serine exhibited similar fast phases of wash-out, a much larger efflux occurred from a slowly exchanging pool with respective time constants (Tslow) of 15.47 +/- 0.45 min (n = 6) and 5.98 +/- 0.46 min (n = 7). 3. A rapid vascular challenge of the pancreas with 100 mM-L-serine transiently accelerated cellular efflux of 2-[14C]MeAIB and L-[3H]serine without affecting wash-out of D-[14C]mannitol. Tracer efflux following cell loading with 2-[14C]MeAIB or L-[3H]serine was not stimulated by a challenge with 100 mM-MeAIB. 4. The time course of amino acid evoked 2-[14C]MeAIB and L-[3H]serine efflux paralleled the extracellular dilution profile of a vascular stimulus, suggesting that the acceleration of efflux was due to trans-stimulation. 5. Trans-stimulation of 2-[14C]MeAIB and L-[3H]serine efflux by a further twenty-two naturally occurring and three synthetic amino acids was then examined. L-Proline, N-methyl-DL-alanine, L-lysine and D-lysine selectively stimulated MeAIB efflux. Efflux of both tracer amino acids was accelerated by aminoisobutyric acid (AIB), L-serine, L

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

    Science.gov (United States)

    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.

  16. Amino acid uptake in rust fungi.

    Science.gov (United States)

    Struck, Christine

    2015-01-01

    The plant pathogenic rust fungi colonize leaf tissue and feed off their host plants without killing them. Certain economically important species of different genera such as Melampsora, Phakopsora, Puccinia, or Uromyces are extensively studied for resolving the mechanisms of the obligate biotrophy. As obligate parasites rust fungi only can complete their life cycle on living hosts where they grow through the leaf tissue by developing an extended network of intercellular hyphae from which intracellular haustoria are differentiated. Haustoria are involved in key functions of the obligate biotrophic lifestyle: suppressing host defense responses and acquiring nutrients. This review provides a survey of rust fungi nitrogen nutrition with special emphasis on amino acid uptake. A variety of sequences of amino acid transporter genes of rust fungi have been published; however, transport activity of only three in planta highly up-regulated amino acid permeases have been characterized. Functional and immunohistochemical investigations have shown the specificity and localization of these transporters. Sequence data of various genome projects allowed identification of numerous rust amino acid transporter genes. An in silico analysis reveals that these genes can be classified into different transporter families. In addition, genetic and molecular data of amino acid transporters have provided new insights in the corresponding metabolic pathways.

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

    Directory of Open Access Journals (Sweden)

    Zimmermann Karel

    2010-01-01

    Full Text Available Abstract Background 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. Results 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. Conclusions 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.

  18. Amino acids in the sedimentary humic and fulvic acids

    Digital Repository Service at National Institute of Oceanography (India)

    Sardessai, S.

    Humic and fulvic acids isolated from a few sediment samples from Arabian Sea and Bay of Bengal were analysed for total hydrolysable amino acids concentration and their composition. The amono acids content of fulvic acids was higher than in the humic...

  19. Economic aspects of amino acids production.

    Science.gov (United States)

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  20. Economic aspects of amino acids production.

    Science.gov (United States)

    Mueller, Udo; Huebner, Susanna

    2003-01-01

    Amino acids represent basic elements of proteins, which as a main source of nutrition themselves serve as a major reserve for maintaining essential functions of humans as well as animals. Taking the recent state of scientific knowledge into account, the industrial sector of amino acids is a priori "suitable" to a specific kind of an ecologically sound way of production, which is based on biotechnology. The following article may point out characteristics of this particular industrial sector and illustrates the applicability of the latest economic methods, founded on development of the discipline of bionics in order to describe economic aspects of amino acids markets. The several biochemical and technological fields of application of amino acids lead to specific market structures in high developed and permanently evolving systems. The Harvard tradition of industrial economics explains how market structures mould the behaviour of the participants and influences market results beyond that. A global increase in intensity of competition confirms the notion that the supply-side is characterised by asymmetric information in contrast to Kantzenbachs concept of "narrow oligopoly" with symmetrical shared knowledge about market information. Departing from this point, certain strategies of companies in this market form shall be derived. The importance of Research and Development increases rapidly and leads to innovative manufacturing methods which replace more polluting manufacturing processes like acid hydrolysis. In addition to these modifications within the production processes the article deals furthermore with the pricing based on product life cycle concept and introduces specific applications of tools like activity based costing and target costing to the field of amino acid production. The authors come to the conclusion that based on a good transferability of latest findings in bionics and ecological compatibility competitors in amino acids manufacturing are well advised

  1. Molecular aggregation in selected crystalline 1:1 complexes of hydrophobic D- and L-amino acids. IV. The L-phenylalanine series.

    Science.gov (United States)

    Görbitz, Carl Henrik; Rissanen, Kari; Valkonen, Arto; Husabø, Asmund

    2009-06-01

    The amino acid L-phenylalanine has been cocrystallized with D-2-aminobutyric acid, C(9)H(11)NO(2).C(4)H(9)NO(2), D-norvaline, C(9)H(11)NO(2).C(5)H(11)NO(2), and D-methionine, C(9)H(11)NO(2).C(5)H(11)NO(2)S, with linear side chains, as well as with D-leucine, C(9)H(11)NO(2).C(6)H(13)NO(2), D-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), and D-allo-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), with branched side chains. The structures of these 1:1 complexes fall into two classes based on the observed hydrogen-bonding pattern. From a comparison with other L:D complexes involving hydrophobic amino acids and regular racemates, it is shown that the structure-directing properties of phenylalanine closely parallel those of valine and isoleucine but not those of leucine, which shares side-chain branching at C(gamma) with phenylalanine and is normally considered to be the most closely related non-aromatic amino acid.

  2. Molecular aggregation in selected crystalline 1:1 complexes of hydrophobic D- and L-amino acids. IV. The L-phenylalanine series.

    Science.gov (United States)

    Görbitz, Carl Henrik; Rissanen, Kari; Valkonen, Arto; Husabø, Asmund

    2009-06-01

    The amino acid L-phenylalanine has been cocrystallized with D-2-aminobutyric acid, C(9)H(11)NO(2).C(4)H(9)NO(2), D-norvaline, C(9)H(11)NO(2).C(5)H(11)NO(2), and D-methionine, C(9)H(11)NO(2).C(5)H(11)NO(2)S, with linear side chains, as well as with D-leucine, C(9)H(11)NO(2).C(6)H(13)NO(2), D-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), and D-allo-isoleucine, C(9)H(11)NO(2).C(6)H(13)NO(2), with branched side chains. The structures of these 1:1 complexes fall into two classes based on the observed hydrogen-bonding pattern. From a comparison with other L:D complexes involving hydrophobic amino acids and regular racemates, it is shown that the structure-directing properties of phenylalanine closely parallel those of valine and isoleucine but not those of leucine, which shares side-chain branching at C(gamma) with phenylalanine and is normally considered to be the most closely related non-aromatic amino acid. PMID:19498234

  3. Postprandial fate of amino acids: adaptation to molecular forms

    NARCIS (Netherlands)

    Nolles, J.A.

    2006-01-01

    During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however, inco

  4. Cometary Amino Acids from the STARDUST Mission

    Science.gov (United States)

    Cook, Jamie Elsila

    2009-01-01

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

  5. Biosynthesis of the Aromatic Amino Acids.

    Science.gov (United States)

    Pittard, James; Yang, Ji

    2008-09-01

    This chapter describes in detail the genes and proteins of Escherichia coli involved in the biosynthesis and transport of the three aromatic amino acids tyrosine, phenylalanine, and tryptophan. It provides a historical perspective on the elaboration of the various reactions of the common pathway converting erythrose-4-phosphate and phosphoenolpyruvate to chorismate and those of the three terminal pathways converting chorismate to phenylalanine, tyrosine, and tryptophan. The regulation of key reactions by feedback inhibition, attenuation, repression, and activation are also discussed. Two regulatory proteins, TrpR (108 amino acids) and TyrR (513 amino acids), play a major role in transcriptional regulation. The TrpR protein functions only as a dimer which, in the presence of tryptophan, represses the expression of trp operon plus four other genes (the TrpR regulon). The TyrR protein, which can function both as a dimer and as a hexamer, regulates the expression of nine genes constituting the TyrR regulon. TyrR can bind each of the three aromatic amino acids and ATP and under their influence can act as a repressor or activator of gene expression. The various domains of this protein involved in binding the aromatic amino acids and ATP, recognizing DNA binding sites, interacting with the alpha subunit of RNA polymerase, and changing from a monomer to a dimer or a hexamer are all described. There is also an analysis of the various strategies which allow TyrR in conjunction with particular amino acids to differentially affect the expression of individual genes of the TyrR regulon. PMID:26443741

  6. Amino acid content of selected plant, algae and insect species: a search for alternative protein sources for use in pet foods.

    Science.gov (United States)

    McCusker, Sarah; Buff, Preston R; Yu, Zengshou; Fascetti, Andrea J

    2014-01-01

    In response to global economic duress and heightened consumer awareness of nutrition and health, sustainable and natural ingredients are in demand. Identification of alternative sources of nitrogen and amino acids, including taurine, may help meet dietary requirements while fostering sustainability and natural feeding approaches. Twenty plants, eighteen marine algae and five insect species were analysed. All samples were freeze-dried, hydrolysed and filtered prior to amino acid analysis. Samples for amino acids were analysed in duplicate and averaged. Nitrogen was analysed and crude protein (CP) determined by calculation. With the exception of taurine concentration in soldier fly larvae, all insects exceeded both the National Research Council's canine and feline minimal requirements (MR) for growth of all essential amino acids (EAA) and CP. Although some plants and marine algal species exceeded the canine and feline MR for growth for EAA and CP, only very low concentrations of taurine were found in plants. Taurine concentration in insects was variable but high, with the greatest concentration found in ants (6·42 mg/g DM) and adult flesh flies (3·33 mg/g DM). Taurine was also high in some macroalgae, especially the red algal species: Mazaella spp. (4·11 mg/g DM), Porphyra spp. (1·22 mg/g DM) and Chondracanthus spp. (6·28 mg/g DM). Preliminary results suggest that insects and some marine algal species may be practical alternatives to traditional protein and supplemental taurine sources in pet foods. Safety, bioavailability, palatability and source variability of alternative items as food ingredients should be investigated prior to incorporation into canine and feline diets.

  7. Influence of variety and sulfur fertilization on the contents of crude protein, and selected amino acids in blue lupins (Lupinus angustifolius L.)

    OpenAIRE

    Böhm, Herwart; Witten, Stephanie; Aulrich, Karen

    2015-01-01

    Legumes are the most important nitrogen suppliers in organic farming, have positive effects in crop rotation and are important protein feedstuffs. In 100 % organic feeding, the amino acid (AA) supply of feedstuffs is of increasing interest. The first- and second-limiting AAs for swine and poultry are lysine (Lys) and the sulfur-containing AAs (SAAs), methionine (Met) and cysteine (Cys), respectively. Since SAAs are limiting in the diet of monogastrics and, besides tryptophane, also in grain l...

  8. Dietary protein effects on growth performance, carcass traits and expression of selected jejunal peptide and amino acid transporters in broiler chickens

    OpenAIRE

    A Corzo; II RE Loar; MT Kidd; SC Burgess

    2011-01-01

    The effect of dietary protein on growth, carcass traits and some specific intestinal intestinal peptide and amino acid transporters in broiler chickens was studied. Birds received a common pre-test diet, and were subsequently fed either a standard positive control diet (PC) or a reduced CP diet (RCP) from 21 to 42 d of age. Growth was negatively impacted with feeding of RCP as manifested by an increase in feed consumption and feed conversion ratio. Carcass traits also showed evidence of negat...

  9. Analysis of Mycosporine-Like Amino Acids in Selected Algae and Cyanobacteria by Hydrophilic Interaction Liquid Chromatography and a Novel MAA from the Red Alga Catenella repens

    OpenAIRE

    Anja Hartmann; Kathrin Becker; Ulf Karsten; Daniel Remias; Markus Ganzera

    2015-01-01

    Mycosporine-like amino acids (MAAs), a group of small secondary metabolites found in algae, cyanobacteria, lichens and fungi, have become ecologically and pharmacologically relevant because of their pronounced UV-absorbing and photo-protective potential. Their analytical characterization is generally achieved by reversed phase HPLC and the compounds are often quantified based on molar extinction coefficients. As an alternative approach, in our study a fully validated hydrophilic interaction l...

  10. Amino acid content of selected plant, algae and insect species: a search for alternative protein sources for use in pet foods.

    Science.gov (United States)

    McCusker, Sarah; Buff, Preston R; Yu, Zengshou; Fascetti, Andrea J

    2014-01-01

    In response to global economic duress and heightened consumer awareness of nutrition and health, sustainable and natural ingredients are in demand. Identification of alternative sources of nitrogen and amino acids, including taurine, may help meet dietary requirements while fostering sustainability and natural feeding approaches. Twenty plants, eighteen marine algae and five insect species were analysed. All samples were freeze-dried, hydrolysed and filtered prior to amino acid analysis. Samples for amino acids were analysed in duplicate and averaged. Nitrogen was analysed and crude protein (CP) determined by calculation. With the exception of taurine concentration in soldier fly larvae, all insects exceeded both the National Research Council's canine and feline minimal requirements (MR) for growth of all essential amino acids (EAA) and CP. Although some plants and marine algal species exceeded the canine and feline MR for growth for EAA and CP, only very low concentrations of taurine were found in plants. Taurine concentration in insects was variable but high, with the greatest concentration found in ants (6·42 mg/g DM) and adult flesh flies (3·33 mg/g DM). Taurine was also high in some macroalgae, especially the red algal species: Mazaella spp. (4·11 mg/g DM), Porphyra spp. (1·22 mg/g DM) and Chondracanthus spp. (6·28 mg/g DM). Preliminary results suggest that insects and some marine algal species may be practical alternatives to traditional protein and supplemental taurine sources in pet foods. Safety, bioavailability, palatability and source variability of alternative items as food ingredients should be investigated prior to incorporation into canine and feline diets. PMID:26101608

  11. Metal induced amino acid adsorption on nanotubes

    Energy Technology Data Exchange (ETDEWEB)

    Chang, Chia M., E-mail: abinitio@dragon.nchu.edu.t [Research Center for the Remediation of Soil and Ground Water Pollution, Department of Soil and Environmental Sciences, National Chung Hsing University, Taichung 402, Taiwan (China); Jalbout, Abraham F. [Departamento de Investigacion en Fisica, Universidad de Sonora, Hermosillo, Sonora C.P., 83000 Mexico (Mexico)

    2010-02-01

    In this work we detail the mechanism by which alkali metal encapsulation inside an armchair (9,9) single walled carbon nanotube (SWNT) can affect external amino acid interactions. Based on our analysis, several configurations revealed that the physical properties of the SWNT systems are modified by using an internally situated Li atom. Density-functional theory calculations reveal that the most favorable interactions of the SWNT system is with tryptophan, threonine and proline that can be directly correlated to the backbone geometry of the amino acid species.

  12. Postprandial fate of amino acids: adaptation to molecular forms

    OpenAIRE

    Nolles, J.A.

    2006-01-01

    During the postprandial phase dietary proteins are digested to peptides and amino acids and absorbed. Once absorbed the peptides are further hydrolyzed to amino acids and transported to the tissues. These amino acids are largely incorporated into body proteins. Not all amino acids are, however, incorporated into body proteins part of these amino acids are oxidized, and can, thus, no longer be utilized to support protein metabolism in the body. The objective of this thesis was to increase the ...

  13. Sensitive determination of D-amino acids in mammals and the effect of D-amino-acid oxidase activity on their amounts.

    Science.gov (United States)

    Hamase, Kenji; Konno, Ryuichi; Morikawa, Akiko; Zaitsu, Kiyoshi

    2005-09-01

    The determination of small amounts of D-amino acids in mammalian tissues is still a challenging theme in the separation sciences. In this review, various gas-chromatographic and high-performance liquid chromatographic methods are discussed including highly selective and sensitive column-switching procedures. Based on these methods, the distributions of D-aspartic acid, D-serine, D-alanine, D-leucine and D-proline have been clarified in the mouse brain. As the regulation mechanisms of D-amino acid amounts in mammals, we focused on the D-amino-acid oxidase, which catalyzes the degradation of D-amino acids. Using the mutant mouse strain lacking D-amino-acid oxidase activity, the effects of the enzymatic activity on the amounts and distributions of various D-amino acids have been investigated. PMID:16141519

  14. Amino acid derived 1,4-dialkyl substituted imidazolones

    DEFF Research Database (Denmark)

    Diness, Frederik; Meldal, Morten Peter

    2010-01-01

    A general method for synthesis of 1,4-substituted imidazolones from amino acids on solid support or in solution has been developed. Amino acid derived 3-Boc-(1,3)-oxazinane (Box) protected amino aldehyde building blocks were coupled through urea bonds to the amino terminal of dipeptides or amino ...

  15. Representation of protein-sequence information by amino acid subalphabets

    DEFF Research Database (Denmark)

    Andersen, C.A.F.; Brunak, Søren

    2004-01-01

    Within computational biology, algorithms are constructed with the aim of extracting knowledge from biological data, in particular, data generated by the large genome projects, where gene and protein sequences are produced in high volume. In this article, we explore new ways of representing protein......-sequence information, using machine learning strategies, where the primary goal is the discovery of novel powerful representations for use in AI techniques. In the case of proteins and the 20 different amino acids they typically contain, it is also a secondary goal to discover how the current selection of amino acids...

  16. Large neutral amino acids in daily practice

    DEFF Research Database (Denmark)

    Ahring, Kirsten Kiær

    2010-01-01

    sampling to measure plasma amino acid (AA) concentrations. The aim of this analysis and treatment is that the patient receives 25-30% of the daily protein requirement from LNAA supplementation and the remaining 70-75% from natural, low-phenylalanine proteins (although some patients have difficulties...

  17. Dietary Supplements and Sports Performance: Amino Acids

    OpenAIRE

    Williams Melvin

    2005-01-01

    Abstract This is the third in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; metabolites, constituents/extracts, or combinations). The major focus is on efficacy of such dietary supplements to enhance exercise or sport performance.

  18. Dietary Supplements and Sports Performance: Amino Acids

    Directory of Open Access Journals (Sweden)

    Williams Melvin

    2005-12-01

    Full Text Available Abstract This is the third in a series of six articles to discuss the major classes of dietary supplements (vitamins; minerals; amino acids; herbs or botanicals; metabolites, constituents/extracts, or combinations. The major focus is on efficacy of such dietary supplements to enhance exercise or sport performance.

  19. Amino acid modifications on tRNA

    Institute of Scientific and Technical Information of China (English)

    Jing Yuan; Kelly Sheppard; Dieter S(o)ll

    2008-01-01

    The accurate formation of cognate aminoacyl-transfer RNAs (aa-tRNAs) is essential for the fidelity of translation.Most amino acids are esterified onto their cognate tRNA isoacceptors directly by aa.tRNA synthetases.However,in the case of four amino acids (Gin,Asn,Cys and Sec),aminoacyl-tRNAs are made through indirect pathways in many organisms across all three domains of life.The process begins with the charging ofnoncognate amino acids to tRNAs by a specialized synthetase in the case of Cys-tRNAcys formation or by synthetases with relaxed specificity,such as the non-discriminating glutamyl-tRNA,non-discriminating aspartyl-tRNA and seryl-tRNA synthetases.The resulting misacylated tRNAs are then converted to cognate pairs through transformation of the amino acids on the tRNA,which is catalyzed by a group of tRNA-dependent modifying enzymes,such as tRNA-dependent amidotransferases,Sep-tRNA:Cys-tRNA synthase,O-phosphoseryi-tRNA kinase and Sep-tRNA:Sec-tRNA synthase.The majority of these indirect pathways are widely spread in all domains of life and thought to be part of the evolutionary process.

  20. tRNAs: cellular barcodes for amino acids

    DEFF Research Database (Denmark)

    Banerjee, Rajat; Chen, Shawn; Dare, Kiley;

    2010-01-01

    The role of tRNA in translating the genetic code has received considerable attention over the last 50 years, and we now know in great detail how particular amino acids are specifically selected and brought to the ribosome in response to the corresponding mRNA codon. Over the same period, it has...... also become increasingly clear that the ribosome is not the only destination to which tRNAs deliver amino acids, with processes ranging from lipid modification to antibiotic biosynthesis all using aminoacyl-tRNAs as substrates. Here we review examples of alternative functions for tRNA beyond...... translation, which together suggest that the role of tRNA is to deliver amino acids for a variety of processes that includes, but is not limited to, protein synthesis....

  1. Selective agonists at group II metabotropic glutamate receptors: synthesis, stereochemistry, and molecular pharmacology of (S)- and (R)-2-amino-4-(4-hydroxy[1,2,5]thiadiazol-3-yl)butyric acid

    DEFF Research Database (Denmark)

    Clausen, Rasmus P; Bräuner-Osborne, Hans; Greenwood, Jeremy R;

    2002-01-01

    )-forms of 2-amino-4-(4-hydroxy[1,2,5]thiadiazol-3-yl)butyric acid (homo-TDPA, 7) and shown that whereas neither enantiomer interacts with AMPA receptors, (S)- and (R)-7 appear to be selective and equipotent agonists at group II mGluRs as represented by the mGluR2 subtype. The activities of (S)- and (R)-7......Homologation of analogues of the central excitatory neurotransmitter glutamic acid (Glu), in which the distal carboxy group has been bioisosterically replaced by acidic heterocyclic units, has previously provided subtype selective ligands for metabotropic Glu receptors (mGluRs). The (S......)-form of the 1,2,5-thiadiazol-3-ol Glu analogue, 2-amino-3-(4-hydroxy[1,2,5]thiadiazol-3-yl)propionic acid (TDPA, 6), is an 2-amino-3-(3-hydroxy-5-methyl-4-isoxazolyl)propionic acid (AMPA) receptor agonist, which in addition stereospecifically activates group I mGluRs. We have now synthesized the (S)- and (R...

  2. Chiral analysis of amino acids using electrochemical composite bienzyme biosensors.

    Science.gov (United States)

    Domínguez, R; Serra, B; Reviejo, A J; Pingarrón, J M

    2001-11-15

    The construction and performance of bienzyme amperometric composite biosensors for the selective determination of l- or d-amino acids is reported. D- or L-Amino acid oxidase, horseradish peroxidase, and the mediator ferrocene were coimmobilized by simple physical inclusion into the bulk of a graphite-70% Teflon electrode matrix. Working conditions including amino acid oxidase loading and pH were optimized. Studies on the repeatability of the amperometric response obtained at +0.00 V, with and without regeneration of the electrode surface by polishing, on the useful lifetime of one single biosensor and on the reproducibility in the fabrication of different biosensors illustrate the robustness of the bioelectrodes design. Calibration plots by both amperometry in stirred solutions and flow injection with amperometric detection were obtained for L-arginine, L-phenylalanine, L-leucine, L-methionine, L-tryptophan, D-leucine, D-methionine, D-serine, and D-valine. Differences in sensitivity were discussed in terms of the hydrophobicity of the substrate and of the electrode surface. The bienzyme composite electrode was applied to the determination of L- and D-amino acids in racemic samples, as well as to the estimation of the L-amino acids content in muscatel grapes. PMID:11700983

  3. [Spectrophotometric determination of aromatic amino compounds with J-acid].

    Science.gov (United States)

    Yin, Xiao-hang; Shi, Wen-jian; Shen, Xin; Ma, Jun-tao; Li, Liang

    2015-01-01

    The problems such as chromogenic reaction selectivity, reaction rate, sensitivity and water-solubility of azo compounds were considered. The molecular structures of coupling components were theoretically designed and screened in the present research The reaction conditions and methods of chromogenic reaction were investigated. J-Acid (2-amino-5-naphthol-7-sulfonic acid) as a coupling reagent to determine aromatic amino compounds was established. In the presence of potassium bromide, at room temperature, nitrite reacted with aromatic amino compounds in the medium of thin hydrochloric acid. Then diazonium salt reacted with J-Acid in the aqueous solution of sodium carbonate, forming coloured azo dye, which had a maximum adsorption at 480 nm. The molar adsorption coeffcients of aniline, 4-aminobenzene sulfonic acid and 1-naphthylamine were 3. 95 X 10(4), 3. 24 X 10(4) and 3. 91 X 10(4) L . mol-1 . cm-1 , respectively. Experimental results showed that common coexisting ions on the surface water did not affect the results of determination. J-Acid of spectrophotometry was used to determine the samples of Shanghai Fu Xing Dao canal. Meanwhile, recovery experiments by standard addition method were done. Experiment results showed that the recoveries of aniline were in the range of 98. 5%-102. 1%, and RSD was 2. 08%. J-Acid is a common organic reagent. It is soluble in water and low volatile, and its toxicity is much lower than N-ethylenediamine. spectrophotometric determination of aromatic amino compounds by J-Acid has the advantage of high sensitivity, good selectivity, simple rapid operation and accurate results, and thus it can be used for the determination of trace aromatic amino compounds in the environmental water.

  4. Selective stimulation of excitatory amino acid receptor subtypes and the survival of cerebellar granule cells in culture: effect of kainic acid

    DEFF Research Database (Denmark)

    Balázs, R; Hack, N; Jørgensen, Ole Steen

    1990-01-01

    Our previous studies showed that the survival of cerebellar granule cells in culture is promoted by treatment with N-methyl-D-aspartate. Here we report on the influence of another glutamate analogue, kainic acid, which, in contrast to N-methyl-D-aspartate, is believed to stimulate transmitter rec...

  5. Radioiodinated 4-iodo-L-meta-tyrosine, a system L selective artificial amino acid: molecular design and transport characterization in Chinese hamster ovary cells (CHO-K1 cells)

    International Nuclear Information System (INIS)

    Introduction: High expression of the system L amino acid transporter has been observed in clinically important tissues including tumors and the blood-brain barrier. We examined amino acid transport system L selectivity of 14C(U)-L-tyrosine (14C-Tyr), 125I-4-iodo-L-meta-tyrosine (4-125I-mTyr), 125I-6-iodo-L-meta-tyrosine (6-125I-mTyr), 125I-3-iodo-α-methyl-L-tyrosine (125I-IMT) and 125I-3-iodo-L-tyrosine (3-125I-Tyr) using Chinese hamster ovary cells (CHO-K1). Methods: Cells in the exponential growth phase were incubated with 18.5 kBq of labeled amino acid in 2 mL of phosphate-buffered saline-based uptake solution and an uptake solution with/without Na+ at 37oC or 4oC. We examined the effects of the following compounds (1.0 mM) on transport: 2-(methylamino)isobutyric acid (a specific inhibitor of system A, in Na+-containing uptake solution); 2-amino-bicyclo[2,2,1]heptane-2-carboxylic acid (a specific inhibitor of system L, in Na+-free uptake solution); sodium azide and 2,4-dinitrophenol (NaN3 and DNP, inhibitors of the generation of adenosine triphosphate); p-aminohippurate and tetraethylammonium (PAH and TEA, inhibitors of organic anion and cation transporters); and L- and D-isomers of natural amino acids. Results: 14C-Tyr exhibited affinity for systems L, A and ASC. 4-125I-mTyr and 3-125I-Tyr exhibited high specificity for system L, whereas 6-125I-mTyr and 125I-IMT exhibited affinity for both systems L and ASC. Uptake of 4-125I-mTyr was markedly reduced by incubation at 4 oC, and was not significantly inhibited by NaN3, DNP, PAH or TEA. The inhibition profiles of the L- and D-isomers of natural amino acids indicated that system L mediates the transport of 4-125I-mTyr. Conclusions: 4-125I-mTyr exhibited the greatest system L specificity (93.46±0.13%) of all of the tested amino acids.

  6. Acquisition of NFKB1-selective DNA binding by substitution of four amino acid residues from NFKB1 into RelA.

    OpenAIRE

    Coleman, T A; Kunsch, C; Maher, M.; Ruben, S. M.; Rosen, C. A.

    1993-01-01

    The subunits of NF-kappa B, NFKB1 (formerly p50) and RelA (formerly p65), belong to a growing family of transcription factors that share extensive similarity to the c-rel proto-oncogene product. The homology extends over a highly conserved stretch of approximately 300 amino acids termed the Rel homology domain (RHD). This region has been shown to be involved in both multimerization (homo- and heterodimerization) and DNA binding. It is now generally accepted that homodimers of either subunit a...

  7. Gastroprotective effect and cytotoxicity of labdeneamides with amino acids.

    Science.gov (United States)

    Schmeda-Hirschmann, Guillermo; Rodríguez, Jaime A; Theoduloz, Cristina; Valderrama, Jaime A

    2011-03-01

    Semisynthetic aromatic amides from ARAUCARIA ARAUCANA diterpene acids have been shown to display a relevant gastroprotective effect with low cytotoxicity. The aim of this work was to assess the gastroprotective effect of amino acid amides from imbricatolic acid and its 8(9)-en isomer in the ethanol/HCl-induced gastric lesions model in mice as well as to determine the cytotoxicity of the obtained compounds on the following human cell lines: normal lung fibroblasts (MRC-5), gastric adenocarcinoma (AGS), and liver hepatocellular carcinoma (Hep G2). The diterpenes 15-acetoxyimbricatolic acid, its 8(9)-en isomer, 15-hydroxyimbricatolic acid, and the 8(9)-en derivative, bearing a COOH function at C-19, were used as starting compounds. New amides with C-protected amino acids were prepared. The study reports the effect of a single oral administration of either compound 50 min before the induction of gastric lesions by ethanol/HCl. Some 20 amino acid monoamides were obtained. Dose-response experiments on the glycyl derivatives showed that at a single oral dose of 100 mg/kg, the compounds presented an effect comparable to the reference drug lansoprazole at 20 mg/kg and at 50 mg/kg reduced gastric lesions by about 50%. All derivatives obtained in amounts > 30 mg were compared at a single oral dose of 50 mg/kg. The best gastroprotective effect was observed for the exomethylene derivatives bearing a valine residue at C-19 either with an acetoxy or free hydroxy group at C-15. The tryptophanyl derivative from the acetate belonging to the 8,9-en series presented selective cytotoxicity against hepatocytes. The glycyl amide of 15-acetoxyimbricatolic acid was the most cytotoxic and less selective compound with IC₅₀ values between 47 and 103 µM for the studied cell lines. This is the first report on the obtention of semisynthetic amino acid amides from labdane diterpenes. PMID:20862639

  8. Intermolecular Vibrations of Hydrophobic Amino Acids

    Science.gov (United States)

    Williams, Michael Roy Casselman

    Hydrophobic amino acids interact with their chemical environment through a combination of electrostatic, hydrogen bonding, dipole, induced dipole, and dispersion forces. These interactions all have their own characteristic energy scale and distance dependence. The low-frequency (0.1-5 THz, 5-150 cm-1) vibrational modes of amino acids in the solid state are a direct indicator of the interactions between the molecules, which include interactions between an amino acid functional group and its surroundings. This information is central to understanding the dynamics and morphology of proteins. The alpha-carbon is a chiral center for all of the hydrophobic amino acids, meaning that they exist in two forms, traditionally referred to as L- and D-enantiomers. This nomenclature indicates which direction the molecule rotates plane-polarized visible light (levorotory and dextrorotory). Chiral a-amino acids in proteins are exclusively the L-variety In the solid state, the crystal lattice of the pure L-enantiomer is the mirror image of the D-enantiomer crystal lattice. These solids are energetically identical. Enantiomers also have identical spectroscopic properties except when the measurement is polarization sensitive. A mixture of equal amounts D- and L-amino acid enantiomers can crystallize into a racemic (DL-) structure that is different from that of the pure enantiomers. Whether a solution of both enantiomers will crystallize into a racemic form or spontaneously resolve into a mixture of separate D- and L-crystals largely depends on the interactions between molecules available in the various possible configurations. This is an active area of research. Low-frequency vibrations with intermolecular character are very sensitive to changes in lattice geometry, and consequently the vibrational spectra of racemic crystals are usually quite distinct from the spectra of the crystals of the corresponding pure enantiomers in the far-infrared (far-IR). THz time-domain spectroscopy (THz

  9. Genetic analysis of amino acid content in wheat grain

    Indian Academy of Sciences (India)

    Xiaoling Jiang; Peng Wu; Jichun Tian

    2014-08-01

    Complete diallel crosses with five parents of common wheat (Triticum aestivum L.) were conducted to analyse inheritance of 17 amino acid contents by using the genetic model including seed, cytoplasmic, maternal and environment interaction effects on quantitative traits of seeds in cereal crops. The results showed that inheritance of 17 amino acid contents, except tyrosine, was controlled by several genetic systems including seed, cytoplasmic, and maternal effects, and by significant gene × environment interaction effects. Seed-direct additive and maternal effects constituted a major part of genetic effects for lysine, tyrosine, arginine, methionine, and glutamic acid content. Seed-direct additive effect formed main part in inheritance of isoleucine and serine contents. Threonine content was mainly governed by maternal additive effect. The other nine amino acid contents were almost entirely controlled by dominance effects. High general heritability of tyrosine (36.3%), arginine (45.8%), lysine (24.7%) and threonine (21.4%) contents, revealed that it could be effective to improve them by direct selection in progenies from appropriate crosses. Interaction heritability for phenylalanine, proline, and histidine content, which was 36.1%, 39.5% and 25.7%, respectively, was higher than for the other amino acids.

  10. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Science.gov (United States)

    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,...

  11. Rotational Study of Natural Amino Acid Glutamine

    Science.gov (United States)

    Varela, Marcelino; Cabezas, Carlos; Alonso, José L.

    2014-06-01

    Recent improvements in laser ablation molecular beam Fourier transform microwave spectroscopy (LA-MB-FTMW) have allowed the investigation of glutamine (COOH-CH(NH2)-CH2-CH2-CONH2), a natural amino acid with a long polar side chain. One dominant structure has been detected in the rotational spectrum. The nuclear quadrupole hyperfine structure of two 14N nuclei has been totally resolved allowing the conclusive identification of the observed species.

  12. Alimentary proteins, amino acids and cholesterolemia.

    Science.gov (United States)

    Blachier, François; Lancha, Antonio H; Boutry, Claire; Tomé, Daniel

    2010-01-01

    Numerous data from both epidemiological and experimental origins indicate that some alimentary proteins and amino acids in supplements can modify the blood LDL cholesterol, HDL cholesterol and total cholesterol. After an initial approval of the health claim for soy protein consumption for the prevention of coronary heart disease, more recently it has been concluded from an overall analysis of literature that isolated soy protein with isoflavones only slightly decrease LDL and total cholesterol. Other plant extracts and also some proteins from animal origin have been reported to exert a lowering effect on blood cholesterol when compared with a reference protein (often casein). The underlying mechanisms are still little understood. Individual amino acids and mixture of amino acids have also been tested (mostly in animal studies) for their effects on cholesterol parameters and on cholesterol metabolism. Methionine, lysine, cystine, leucine, aspartate and glutamate have been tested individually and in combination in different models of either normo or hypercholesterolemic animals and found to be able to modify blood cholesterol and/or LDL cholesterol and/or HDL cholesterol. It is however not known if these results are relevant to human nutrition.

  13. A Green Synthesis of Diisopropyl Phosphoryl Amino Acid

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    In this paper, we report that diisopropyl phosphoryl amino acid could be prepared with reasonable yields under solvent-free condition by adding amino acid to the mixture of diisopropyl phosphite and N-chlorodiisopropylamine.

  14. Amino acids as co-amorphous excipients for simvastatin and glibenclamide

    DEFF Research Database (Denmark)

    Laitinen, Riikka; Löbmann, Korbinian; Grohganz, Holger;

    2014-01-01

    to a few drugs and amino acids. To facilitate the rational selection of amino acids, the practical importance of the amino acid coming from the biological target site of the drug (and associated intermolecular interactions) needs to be established. In the present study, the formation of co......-amorphous systems using cryomilling and combinations of two poorly water-soluble drugs (simvastatin and glibenclamide) with the amino acids aspartic acid, lysine, serine, and threonine was investigated. Solid-state characterization with X-ray powder diffraction, differential scanning calorimetry, and Fourier...

  15. Selective 'unlabeling' of amino acids in fractionally 13C labeled proteins: An approach for stereospecific NMR assignments of CH3 groups in Val and Leu residues

    Energy Technology Data Exchange (ETDEWEB)

    Atreya, H.S.; Chary, K.V.R. [Tata Institute of Fundamental Research, Department of Chemical Sciences (India)

    2001-03-15

    A novel methodology for stereospecific NMR assignments of methyl (CH{sub 3}) groups of Val and Leu residues in fractionally {sup 13}C-labeled proteins is presented. The approach is based on selective 'unlabeling' of specific amino acids in proteins while fractionally {sup 13}C-labeling the rest. A 2D [{sup 13}C-{sup 1}H] HSQC spectrum recorded on such a sample is devoid of peaks belonging to the 'unlabeled' amino acid residues. Such spectral simplification aids in unambiguous stereospecific assignment of diastereotopic CH{sub 3} groups in Val and Leu residues in large proteins. This methodology has been demonstrated on a 15 kDa calcium binding protein from Entamoeba histolytica (Eh-CaBP)

  16. Deorphanization of GPRC6A: a promiscuous L-alpha-amino acid receptor with preference for basic amino acids

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Hansen, Kasper B; Balsgaard, Anders;

    2005-01-01

    and was employed to rationally select potential ligands. Measurement of Ca2+-dependent chloride currents in Xenopus laevis oocytes facilitated the deorphanization of h6A/5.24 and identification of L-alpha-amino acids as agonists. The most active agonists were basic L-alpha-amino acids, L-Arg, L-Lys, and L......One of the most important tasks of molecular pharmacology is the deorphanization of the large number of G-protein-coupled receptors with unidentified endogenous agonists. We recently reported the cloning and analysis of expression of a novel human family C G-protein-coupled receptor, termed hGPRC6A....... To identify agonists at this orphan receptor, we faced the challenges of achieving surface expression in mammalian cell lines and establishing an appropriate functional assay. Generating a chimeric receptor construct, h6A/5.24, containing the ligand binding amino-terminal domain (ATD) of hGPRC6A...

  17. Amino acid absorption and homeostasis in mice lacking the intestinal peptide transporter PEPT1.

    Science.gov (United States)

    Nässl, Anna-Maria; Rubio-Aliaga, Isabel; Fenselau, Henning; Marth, Mena Katharina; Kottra, Gabor; Daniel, Hannelore

    2011-07-01

    The intestinal peptide transporter PEPT1 mediates the uptake of di- and tripeptides derived from dietary protein breakdown into epithelial cells. Whereas the transporter appears to be essential to compensate for the reduced amino acid delivery in patients with mutations in amino acid transporter genes, such as in cystinuria or Hartnup disease, its physiological role in overall amino acid absorption is still not known. To assess the quantitative importance of PEPT1 in overall amino acid absorption and metabolism, PEPT1-deficient mice were studied by using brush border membrane vesicles, everted gut sacs, and Ussing chambers, as well as by transcriptome and proteome analysis of intestinal tissue samples. Neither gene expression nor proteome profiling nor functional analysis revealed evidence for any compensatory changes in the levels and/or function of transporters for free amino acids in the intestine. However, most plasma amino acid levels were increased in Pept1(-/-) compared with Pept1(+/+) animals, suggesting that amino acid handling is altered. Plasma appearance rates of (15)N-labeled amino acids determined after intragastric administration of a low dose of protein remained unchanged, whereas administration of a large protein load via gavage revealed marked differences in plasma appearance of selected amino acids. PEPT1 seems, therefore, important for overall amino acid absorption only after high dietary protein intake when amino acid transport processes are saturated and PEPT1 can provide additional absorption capacity. Since renal amino acid excretion remained unchanged, elevated basal concentrations of plasma amino acids in PEPT1-deficient animals seem to arise mainly from alterations in hepatic amino acid metabolism. PMID:21350187

  18. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Science.gov (United States)

    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....

  19. Metabolism of amino acid amides in Pseudomonas putida ATCC 12633

    NARCIS (Netherlands)

    Hermes, H.F.M.; Croes, L.M.; Peeters, W.P.H.; Peters, P.J.H.; Dijkhuizen, L.

    1993-01-01

    The metabolism of the natural amino acid L-valine, the unnatural amino acids D-valine, and D-, L-phenylglycine (D-, L-PG), and the unnatural amino acid amides D-, L-phenylglycine amide (D, L-PG-NH2) and L-valine amide (L-Val-NH2) was studied in Pseudomonas putida ATCC 12633. The organism possessed c

  20. Origin, Microbiology, Nutrition, and Pharmacology of D-Amino Acids

    Science.gov (United States)

    Exposure of food proteins to certain processing conditions induces two major chemical changes: racemization of all L-amino acids (LAA) to D-amino acids (DAA) and concurrent formation of crosslinked amino acids such as lysinoalanine (LAL). The diet contains both processing-induced and naturally-form...

  1. Amino acid biogeo- and stereochemistry in coastal Chilean sediments

    DEFF Research Database (Denmark)

    Lomstein, Bente Aagaard; Jørgensen, Bo Barker; Schubert, Carsten J.;

    2006-01-01

    The spatial distribution of total hydrolysable amino acids (THAA) and amino acid enantiomers (D- and L-forms) was investigated in sediments underlying two contrasting Chilean upwelling regions,: at ~23°S off Antofagasta and at ~36°S off Concepcion. The contribution of amino acids to total organic...

  2. A Convenient Synthesis of Amino Acid Methyl Esters

    Directory of Open Access Journals (Sweden)

    Yaowu Sha

    2008-05-01

    Full Text Available A series of amino acid methyl ester hydrochlorides were prepared in good toexcellent yields by the room temperature reaction of amino acids with methanol in thepresence of trimethylchlorosilane. This method is not only compatible with natural aminoacids, but also with other aromatic and aliphatic amino acids.

  3. Association Analysis of the Amino Acid Contents in Rice

    Institute of Scientific and Technical Information of China (English)

    Weiguo Zhao; Eun-Jin Park; Jong-Wook Chung; Yong-Jin Park; III-Min Chung; Joung-Kuk Ahn; Gwang-Ho Kim

    2009-01-01

    The main objective of the present study was to identify simple sequence repeat (SSR) markers associated with the amino acid content of rice (Oryza sativa L.). SSR markers were selected by prescreening for the relationship to amino acid content. Eighty-four rice landrace accessions from Korea were evaluated for 16 kinds of amino acids in brown rice and genotyped with 25 SSR markers. Analysis of population structure revealed four subgroups in the population. Linkage disequilibrium (LD) patterns and distributions are of fundamental importance for genome-wide mapping associations. The mean r2 value for all intrachromosomal loci pairs was 0.033. LD between linked markers decreased with distance. Marker-trait associations were investigated using the unified mixed-model approach, considering both population structure (Q) and kinship (K). A total of 42 marker-trait associations with amino acids (P < 0.05) were identified using 15 different SSR markers covering three chromosomes and explaining more than 40% of the total variation. These results suggest that association analysis In rice is a viable alternative to quantitative trait loci mapping and should help rice breeders develop strategies for improving rice quality.

  4. Amino acid transport in taxonomically diverse cyanobacteria and identification of two genes encoding elements of a neutral amino acid permease putatively involved in recapture of leaked hydrophobic amino acids.

    Science.gov (United States)

    Montesinos, M L; Herrero, A; Flores, E

    1997-02-01

    The activities of uptake of thirteen 14C-labeled amino acids were determined in nine cyanobacteria, including the unicellular strains Synechococcus sp. strain PCC 7942 and Synechocystis sp. strain PCC 6803; the filamentous strain Pseudanabaena sp. strain PCC 6903, and the filamentous, heterocyst-forming strains Anabaena sp. strains PCC 7120 and PCC 7937; Nostoc sp. strains PCC 7413 and PCC 7107; Calothrix sp. strain PCC 7601 (which is a mutant unable to develop heterocysts); and Fischerella muscicola UTEX 1829. Amino acid transport mutants, selected as mutants resistant to some amino acid analogs, were isolated from the Anabaena, Nostoc, Calothrix, and Pseudanabaena strains. All of the tested cyanobacteria bear at least a neutral amino acid transport system, and some strains also bear transport systems specific for basic or acidic amino acids. Two genes, natA and natB, encoding elements (conserved component, NatA, and periplasmic binding protein, NatB) of an ABC-type permease for neutral amino acids were identified by insertional mutagenesis of strain PCC 6803 open reading frames from the recently published genomic DNA sequence of this cyanobacterium. DNA sequences homologous to natA and natB from strain PCC 6803 were detected by hybridization in eight cyanobacterial strains tested. Mutants unable to transport neutral amino acids, including natA and natB insertional mutants, accumulated in the extracellular medium a set of amino acids that always included Ala, Val, Phe, Ile, and Leu. A general role for a cyanobacterial neutral amino acid permease in recapture of hydrophobic amino acids leaked from the cells is suggested.

  5. Quantitative detection of single amino acid polyrnorphisms by targeted proteornics

    Institute of Scientific and Technical Information of China (English)

    Zhi-Duan Su; Jia-Rui Wu; Liang Sun; Dan-Xia Yu; Rong-Xia Li; Huai-Xing Li; Zhi-Jie Yu; Quan-Hu Sheng; Xu Lin; RongZeng

    2011-01-01

    Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale. However, polymorphisms at the proteome level in population scale remain elusive. In the present study, we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level, and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma. The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach, and their associations with both obesity and diabetes were further analyzed. This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits. In addition, the SRM approach allows us for the first time to separately measure the absolute concentration of each SAP peptide in the heterozygotes, which also shows different associations with particular traits.%Single-nucleotide polymorphisms (SNPs) are recognized as one kind of major genetic variants in population scale.However,polymorphisms at the proteome level in population scale remain elusive.In the present study,we named amino acid variances derived from SNPs within coding regions as single amino acid polymorphisms (SAPs) at the proteome level,and developed a pipeline of non-targeted and targeted proteomics to identify and quantify SAP peptides in human plasma.The absolute concentrations of three selected SAP-peptide pairs among 290 Asian individuals were measured by selected reaction monitoring (SRM) approach,and their associations with both obesity and diabetes were further analyzed.This work revealed that heterozygotes and homozygotes with various SAPs in a population could have different associations with particular traits.In addition,the SRM approach allows us for the first time to separately measure the absolute

  6. Nutritional and medicinal aspects of D-amino acids.

    Science.gov (United States)

    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.

  7. Analysis of Mycosporine-Like Amino Acids in Selected Algae and Cyanobacteria by Hydrophilic Interaction Liquid Chromatography and a Novel MAA from the Red Alga Catenella repens

    Directory of Open Access Journals (Sweden)

    Anja Hartmann

    2015-10-01

    Full Text Available Mycosporine-like amino acids (MAAs, a group of small secondary metabolites found in algae, cyanobacteria, lichens and fungi, have become ecologically and pharmacologically relevant because of their pronounced UV-absorbing and photo-protective potential. Their analytical characterization is generally achieved by reversed phase HPLC and the compounds are often quantified based on molar extinction coefficients. As an alternative approach, in our study a fully validated hydrophilic interaction liquid chromatography (HILIC method is presented. It enables the precise quantification of several analytes with adequate retention times in a single run, and can be coupled directly to MS. Excellent linear correlation coefficients (R2 > 0.9991 were obtained, with limit of detection (LOD values ranging from 0.16 to 0.43 µg/mL. Furthermore, the assay was found to be accurate (recovery rates from 89.8% to 104.1% and precise (intra-day precision: 5.6%, inter-day precision ≤6.6%. Several algae were assayed for their content of known MAAs like porphyra-334, shinorine, and palythine. Liquid chromatography-mass spectrometry (LC-MS data indicated a novel compound in some of them, which could be isolated from the marine species Catenella repens and structurally elucidated by nuclear magnetic resonance spectroscopy (NMR as (E-3-hydroxy-2-((5-hydroxy-5-(hydroxymethyl-2-methoxy-3-((2-sulfoethylaminocyclohex-2-en-1-ylideneamino propanoic acid, a novel MAA called catenelline.

  8. Protein and Amino Acid Requirements during Pregnancy.

    Science.gov (United States)

    Elango, Rajavel; Ball, Ronald O

    2016-07-01

    Protein forms an essential component of a healthy diet in humans to support both growth and maintenance. During pregnancy, an exceptional stage of life defined by rapid growth and development, adequate dietary protein is crucial to ensure a healthy outcome. Protein deposition in maternal and fetal tissues increases throughout pregnancy, with most occurring during the third trimester. Dietary protein intake recommendations are based on factorial estimates because the traditional method of determining protein requirements, nitrogen balance, is invasive and undesirable during pregnancy. The current Estimated Average Requirement and RDA recommendations of 0.88 and 1.1 g · kg(-1) · d(-1), respectively, are for all stages of pregnancy. The single recommendation does not take into account the changing needs during different stages of pregnancy. Recently, with the use of the minimally invasive indicator amino acid oxidation method, we defined the requirements to be, on average, 1.2 and 1.52 g · kg(-1) · d(-1) during early (∼16 wk) and late (∼36 wk) stages of pregnancy, respectively. Although the requirements are substantially higher than current recommendations, our values are ∼14-18% of total energy and fit within the Acceptable Macronutrient Distribution Range. Using swine as an animal model we showed that the requirements for several indispensable amino acids increase dramatically during late gestation compared with early gestation. Additional studies should be conducted during pregnancy to confirm the newly determined protein requirements and to determine the indispensable amino acid requirements during pregnancy in humans. PMID:27422521

  9. The Role of Microbial Amino Acid Metabolism in Host Metabolism

    Directory of Open Access Journals (Sweden)

    Evelien P. J. G. Neis

    2015-04-01

    Full Text Available 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.

  10. Reasons for the occurrence of the twenty coded protein amino acids

    Science.gov (United States)

    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.

  11. Comparative Amino Acid Sequences of Dengue Viruses

    OpenAIRE

    Haishi, Shozo; TANAKA Mariko; Igarashi, Akira

    1990-01-01

    Amino acid (AA) sequences of 4 serotype of dengue viruses deduced from their nucleotide (nt) sequences of genomic RNA were analyzed for each genome segment and each stretch of 10 AA residues. Precursor of membrane protein (pM), and 4 nonstructural proteins (NS1, NS3, NS4B, NS5) were highly conserved, while another nonstructural protein (NS2A) was least conserved among 5 strains of dengue viruses. When homology was compared among heterotypic viruses, type 1 and type 3 dengue viruses showed clo...

  12. D-Amino Acids Trigger Biofilm Disassembly

    OpenAIRE

    Kolodkin-Gal, Illana; Romero, Diego; Cao, Shugeng; Clardy, Jon; Kolter, Roberto; Losick, Richard

    2010-01-01

    Bacteria form communities known as biofilms, which disassemble over time. Here we found that prior to biofilm disassembly Bacillus subtilis produced a factor that prevented biofilm formation and could break down existing biofilms. The factor was shown to be a mixture of D-leucine, D-methionine, D-tyrosine and D-tryptophan that could act at nanomolar concentrations. D-amino acid treatment caused the release of amyloid fibers that linked cells in the biofilm together. Mutants able to form biofi...

  13. Photoinduced dynamics in protonated aromatic amino acid

    CERN Document Server

    Grégoire, Gilles; Barat, Michel; Fayeton, Jacqueline; Dedonder-Lardeux, Claude; Jouvet, Christophe

    2008-01-01

    UV photoinduced fragmentation of protonated aromatics amino acids have emerged the last few years, coming from a situation where nothing was known to what we think a good understanding of the optical properties. We will mainly focus this review on the tryptophan case. Three groups have mostly done spectroscopic studies and one has mainly been involved in dynamics studies of the excited states in the femtosecond/picosecond range and also in the fragmentation kinetics from nanosecond to millisecond. All these data, along with high level ab initio calculations, have shed light on the role of the different electronic states of the protonated molecules upon the fragmentation mechanisms.

  14. Experimental Evolution of a Green Fluorescent Protein Composed of 19 Unique Amino Acids without Tryptophan

    Science.gov (United States)

    Kawahara-Kobayashi, Akio; Hitotsuyanagi, Mitsuhiro; Amikura, Kazuaki; Kiga, Daisuke

    2014-04-01

    At some stage of evolution, genes of organisms may have encoded proteins that were synthesized using fewer than 20 unique amino acids. Similar to evolution of the natural 19-amino-acid proteins GroEL/ES, proteins composed of 19 unique amino acids would have been able to evolve by accumulating beneficial mutations within the 19-amino-acid repertoire encoded in an ancestral genetic code. Because Trp is thought to be the last amino acid included in the canonical 20-amino-acid repertoire, this late stage of protein evolution could be mimicked by experimental evolution of 19-amino-acid proteins without tryptophan (Trp). To further understand the evolution of proteins, we tried to mimic the evolution of a 19-amino-acid protein involving the accumulation of beneficial mutations using directed evolution by random mutagenesis on the whole targeted gene sequence. We created active 19-amino-acid green fluorescent proteins (GFPs) without Trp from a poorly fluorescent 19-amino-acid mutant, S1-W57F, by using directed evolution with two rounds of mutagenesis and selection. The N105I and S205T mutations showed beneficial effects on the S1-W57F mutant. When these two mutations were combined on S1-W57F, we observed an additive effect on the fluorescence intensity. In contrast, these mutations showed no clear improvement individually or in combination on GFPS1, which is the parental GFP mutant composed of 20 amino acids. Our results provide an additional example for the experimental evolution of 19-amino-acid proteins without Trp, and would help understand the mechanisms underlying the evolution of 19-amino-acid proteins. (236 words)

  15. Stereoselectivities in α- and β-Amino Acids Catalyzed Mannich Reactions Involving Cyclohexanone

    Institute of Scientific and Technical Information of China (English)

    WANG Ying; FU Ai-ping; LI Hong-liang; TIAN Feng-hui; YUAN Shu-ping; SI Hong-zong; DUAN Yun-bo; WANG Zong-hua

    2011-01-01

    The effects of two different amino acid catalysts on the stereoselectivities in the direct Mannich reactions of cyclohexanone,p-anisidine and p-nitrobenzaldehyde were studied with the aid of density functional theory.Transition states of the stereo-determining C-C bond-forming step with the addition of enamine intermediate to the imine for the L-proline(α-amino acid) and (R)-3-pyrrolidinecarboxylic acid(β-amino acid)-catalyzed processes were reported.B3LYP/6-31G** calculations provide a good explanation for the opposite syn vs.anti diastereoselectivities of these two different kinds of catalysts(syn-selectivity for the α-amino acid catalysts,anti-selectivity for the β-amino acid catalysts).Calculated and observed diastereomeric ratio and enantiomeric excess values are in reasonable agreement.

  16. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    Science.gov (United States)

    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.

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

    Science.gov (United States)

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

    1999-01-01

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

  18. Conformational properties of oxazoline-amino acids

    Science.gov (United States)

    Staś, Monika; Broda, Małgorzata A.; Siodłak, Dawid

    2016-04-01

    Oxazoline-amino acids (Xaa-Ozn) occur in natural peptides of potentially important bioactivity. The conformations of the model compounds: Ac-(S)-Ala-Ozn(4R-Me), Ac-(S)-Ala-Ozn(4S-Me), and (gauche+, gauche-, anti) Ac-(S)-Val-Ozn(4R-Me) were studied at meta-hybrid M06-2X/6-311++G(d,p) method including solvent effect. Boc-L-Ala-L-Ozn-4-COOMe and Boc-L-Val-L-Ozn-4-COOMe were synthesized and studied by FT-IR and NMR-NOE methods. The conformations in crystal state were gathered from the Cambridge Structural Data Base. The main conformational feature of the oxazoline amino acids is the conformation β2 (ϕ,ψ ∼ -161°, -6°), which predominates in weakly polar environment and still is accessible in polar surrounding. The changes of the conformational preferences towards the conformations αR (ϕ,ψ ∼ -70°, -15°) and then β (ϕ,ψ ∼ -57°, -155°) are observed with increase of the environment polarity.

  19. Selective Colorimetric Recognition Properties of the Bis(indolyl) methene Receptors for Amino Acids%双吲哚烯类受体对氨基酸的比色识别作用

    Institute of Scientific and Technical Information of China (English)

    王利涛; 何晓明; 郭勇; 徐健; 邵士俊

    2011-01-01

    设计合成了一系列3,3′-双吲哚烯类受体分子,应用紫外-可见吸收光谱研究了该类受体对20种天然氨基酸分子的识别作用.结果表明,在乙腈-水溶液中,双吲哚烯受体分子可以通过其氢键受体位点的质子化作用比色识别天冬氨酸及谷氨酸等酸性氨基酸;而硝基取代的双吲哚烯受体分子则通过其氢键供体位点的去质子化作用比色识别精氨酸和赖氨酸等碱性氨基酸.在乙腈-水的中性缓冲溶液体系中,硝基取代的双吲哚烯类受体分子通过与巯基发生亲核加成反应,高选择性地比色识别半胱氨酸和同型半胱氨酸.%The development of artificial receptors for the selective recognition of biologically important species has been one of the best concerned topic in the field of supramolecular chemistry. The effective and selective molecular recognition or sensing of unprotected amino acids in aqueous solution is still a challenging problem due to their highly hydrophilic character. In this paper, a series of 3 ,3'-bis( indolyl) methene receptors was designed and synthesized, and the recognition properties of the receptors for 20 natural amino acids were studied via UV-Vis spectroscopic techniques. The result indicated that the receptors exhibited selective colorimet-ric sensing for amino acids by protonated/deprotonated process of the hydrogen bond site of the receptors in CH3CN/H2O(1: 1, volume ratio). The introduction of methoxy group into indole ring, which increased the basicity of the hydrogen bond acceptor unit, can promote the occurrence of the protonated process and increase the sensing sensitivity for acidic amino acids. The receptors with nitro group exhibited obviously colorimetric sensing for basic amino acids (arginine, lysine) due to the deprotonation of the hydrogen bond donor unit of receptors. In CH3CN/H2O(1: 1, volume ratio; 0.01 mol/L HEPES, pH =7.4) neutral buffered solution, the receptors without nitro group showed

  20. Fuzzy clustering of physicochemical and biochemical properties of amino acids.

    Science.gov (United States)

    Saha, Indrajit; Maulik, Ujjwal; Bandyopadhyay, Sanghamitra; Plewczynski, Dariusz

    2012-08-01

    In this article, we categorize presently available experimental and theoretical knowledge of various physicochemical and biochemical features of amino acids, as collected in the AAindex database of known 544 amino acid (AA) indices. Previously reported 402 indices were categorized into six groups using hierarchical clustering technique and 142 were left unclustered. However, due to the increasing diversity of the database these indices are overlapping, therefore crisp clustering method may not provide optimal results. Moreover, in various large-scale bioinformatics analyses of whole proteomes, the proper selection of amino acid indices representing their biological significance is crucial for efficient and error-prone encoding of the short functional sequence motifs. In most cases, researchers perform exhaustive manual selection of the most informative indices. These two facts motivated us to analyse the widely used AA indices. The main goal of this article is twofold. First, we present a novel method of partitioning the bioinformatics data using consensus fuzzy clustering, where the recently proposed fuzzy clustering techniques are exploited. Second, we prepare three high quality subsets of all available indices. Superiority of the consensus fuzzy clustering method is demonstrated quantitatively, visually and statistically by comparing it with the previously proposed hierarchical clustered results. The processed AAindex1 database, supplementary material and the software are available at http://sysbio.icm.edu.pl/aaindex/ .

  1. Selective adsorption in two porous triazolate–oxalate-bridged antiferromagnetic metal-azolate frameworks obtained via in situ decarboxylation of 3-amino-1,2,4-triazole-5-carboxylic acid

    International Nuclear Information System (INIS)

    Solvothermal reactions of metal salts, 3-amino-1,2,4-triazole-5-carboxylic acid (H2atzc) and ammonium oxalate in different temperature produced two metal azolate frameworks, namely, [Cu3(atzc)2(atz)(ox)]·1.5H2O (1) and [Co5(atz)4(ox)3(HCOO)2]·DMF (2) (H2atzc=3-amino-1,2,4-triazole-5-carboxylic acid, Hatz=3-amino-1,2,4-triazole, and ox=oxalate), in which the atzc precusor was in situ decarboxylated. Structural determination reveals that 1 contains [Cu3(atzc)2(atz)]2− layers of mixed μ4-atzc and μ3-atz ligands, which are pillared by ox2− groups to form a 3D porous framework. Compound 2 contains 2D layers with basic spindle-shaped decanuclear units, which extended by ox2− and formates to form 3D porous framework. Gas adsorption investigation revealed that two kinds of frameworks exhibited selective CO2 over N2 sorption. Moreover, activated 2 shows H2 storage capacity. Additionally, magnetic properties of both the compounds have been investigated. - Graphical abstract: Solvothermal reactions of metal salts, 3-amino-1,2,4-triazole-5-carboxylate and oxalate produced two metal azolate frameworks, which could store gas molecules, especially H2 due to small pores. in situ decarboxylation of precursor was observed. - Highlights: • Two MAFs were synthesized via in situ decarboxylation of H2atzc. • Both activated frameworks exhibited selective CO2 over N2 sorption. • Activated 2 could adsorb H2, which makes it promising candidates for gas storage

  2. Adsorption of amino acids by fullerenes and fullerene nanowhiskers

    Science.gov (United States)

    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 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.

  3. Effect of L-lysine on expression of selected genes, serum concentration of amino acids, muscle growth and performance of growing pigs.

    Science.gov (United States)

    Morales, A; García, H; Arce, N; Cota, M; Zijlstra, R T; Araiza, B A; Cervantes, M

    2015-08-01

    Lysine (Lys) is the first limiting amino acid (AA) in most feed formulations for pigs and most abundant, along with leucine, in muscle proteins. An experiment was conducted with 17 pigs (17.7 ± 0.05 kg initial BW) to identify a role of dietary Lys in the control of protein synthesis in pigs. Fourteen pigs were randomly assigned to one of the two wheat-based dietary treatments: Lys-deficient, 3.0 g/kg (DEF) and Lys-adequate, 10.8 g/kg (ADE). Samples from jejunum mucosa, liver, Longissumus and Semitendinosus muscles, and blood were collected. The other three pigs were sacrificed at the beginning of the trial to measure basal carcass composition. Weight gain, gain:feed ratio, Lys intake and loin eye area were greater in ADE than in DEF pigs (p DEF pigs. Expression of AA transporters CAT-1 was lower (p < 0.05), serum Lys was higher and serum Val was lower in pigs fed the ADE diet. The higher muscularity, MyHC IIb expression in Semitendinosus muscle and Lys serum of pigs fed the ADE diet suggest that Lys increases growth rate not only by functioning as protein construction unit but also as potential control of the protein synthesis process. PMID:25354230

  4. Effect of L-lysine on expression of selected genes, serum concentration of amino acids, muscle growth and performance of growing pigs.

    Science.gov (United States)

    Morales, A; García, H; Arce, N; Cota, M; Zijlstra, R T; Araiza, B A; Cervantes, M

    2015-08-01

    Lysine (Lys) is the first limiting amino acid (AA) in most feed formulations for pigs and most abundant, along with leucine, in muscle proteins. An experiment was conducted with 17 pigs (17.7 ± 0.05 kg initial BW) to identify a role of dietary Lys in the control of protein synthesis in pigs. Fourteen pigs were randomly assigned to one of the two wheat-based dietary treatments: Lys-deficient, 3.0 g/kg (DEF) and Lys-adequate, 10.8 g/kg (ADE). Samples from jejunum mucosa, liver, Longissumus and Semitendinosus muscles, and blood were collected. The other three pigs were sacrificed at the beginning of the trial to measure basal carcass composition. Weight gain, gain:feed ratio, Lys intake and loin eye area were greater in ADE than in DEF pigs (p Muscle-related carcass characteristics were better, and myosin heavy chain IIb expression (MyHC IIb) in Semitendinosus was higher in ADE than in DEF pigs. Expression of AA transporters CAT-1 was lower (p muscle and Lys serum of pigs fed the ADE diet suggest that Lys increases growth rate not only by functioning as protein construction unit but also as potential control of the protein synthesis process.

  5. Complexes of selected transition metal ions with 4-oxo-4-{[3-(trifluoromethyl)phenyl]amino}but-2-enoic acid: Synthesis, structure and magnetic properties

    Science.gov (United States)

    Ferenc, Wiesława; Sadowski, Paweł; Tarasiuk, Bogdan; Cristóvão, Beata; Drzewiecka-Antonik, Aleksandra; Osypiuk, Dariusz; Sarzyński, Jan

    2015-07-01

    The new complexes of 4-oxo-4-{[3-(trifluoromethyl)phenyl]amino}but-2-enoic acid, HL anion with Mn(II), Co(II), Ni(II), Cu(II) and Pr(III), Nd(III), Sm(III), Gd(III), Dy(III), Ho(III), Er(III), Y(III) were synthesized and some of their physico-chemical properties investigated. The complexes form hydrates with two or three molecules of water. The carboxylate groups act as a bidentate bridging or chelating ligand. The compounds of Pr(III), Nd(III), Sm(III), Gd(III), Dy(III), Ho(III), Er(III) and Y(III) are amorphous solids while those of Cu(II), Co(II), Ni(II) and Mn(II) crystalline ones that crystallize in monoclinic system. Complex of Cu(II) is the centrosymmetric dinuclear compound. Around both Cu(II) cations the tetragonal pyramide is formed. Being heated in air at 293-1173 K the complexes are decomposed in three steps. The oxides of appropriate metals are the final products of complex decomposition. All analysed compounds obey Curie-Weiss law. They show the paramagnetic properties with the ferromagnetic interactions between molecular centres.

  6. Turkey-hen amino acid composition of brain and eyes

    International Nuclear Information System (INIS)

    The amino acids composition of the brain and eyes of the mature Turkey-hen (Meleagris gallopavo L.), were determined on dry weight basis. Total essential amino acids ranged from 35.1-36.0 g/100 g as 49.5-49.8% of the total amino acids. The amino acid score showed that lysine ranged from 0.76-0.91 (on whole hen.s egg comparison), 0.85-1.03 (on provisional essential amino acid scoring pattern), and 0.81-0.98 (on suggested requirement of the essential amino acid of a preschool child). The predicted protein efficiency ratio was 1.94-2.41, whilst essential amino acid index range was 1.06-1.08 and the calculated isoelectric point range was 3.97-4.18. The correlation coefficient (rxy) was positively high and significant at r = 0.01 for the total amino acids, amino acid scores (on the whole hen.s egg comparisons made) and the isoelectric point. On the whole, the eyes were better in 12/18 or 66.7% parameters of the amino acids than the brain of Turkey-Hen. (author)

  7. Influence of mineralogy on the preservation of amino acids under simulated Mars conditions

    Science.gov (United States)

    dos Santos, Renato; Patel, Manish; Cuadros, Javier; Martins, Zita

    2016-10-01

    reactions with reactive oxygen species generated under Mars-like conditions. Olivine (forsterite) preserved more amino acids than the other non-clay silicates due to low or absent ferrous iron. Our results show that D- and L-amino acids are degraded at equal rates, and that there is a certain correlation between preservation/degradation of amino acids and their molecular structure: alkyl substitution in the α-carbon seem to contribute towards amino acid stability under UV radiation. These results contribute towards a better selection of sampling sites for the search of biomarkers on future life detection missions on the surface of Mars.

  8. A new theoretical model for the origin of amino acid homochirality

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    Amino acid homochirality, as a unique behavior of life, could have originated synchronously with the genetic code. In this paper, phosphoryl amino-acid -5'-nucleosides with P-N bond are postulated to be a chiral origin model in prebiotic molecular evolution. The enthalpy change in the intramolecular interaction between the nucleotide base and the amino-acid side-chain determines the stability of the particular complex, resulting in a preferred conformation associated with the chirality of amino acids. Based on the theoretical model, our experiments and calculations show that the chiral selection of the earliest amino acids for L-enantiomers seems to be a strict stereochemical/physicochemical determinism. As other amino acids developed biosynthetically from the earliest amino acids, we infer that the chirality of the later amino acids was inherited from the precursor amino acids. This idea probably goes far back in history, but it is hoped that it will be a guide for further experiments in this area.

  9. Interconnection between the protein solubility and amino acid and dipeptide compositions.

    Science.gov (United States)

    Niu, Xiaohui; Li, Nana; Chen, Dinyan; Wang, Zengzhen

    2013-01-01

    Obtaining soluble proteins in sufficient concentrations helps increase the overall success rate in various experimental studies. Protein solubility is an individual trait ultimately determined by its primary protein sequence. Exploring the interconnection between the protein solubility and the compositions of protein sequence is instrumental for setting priorities on targets in large scale proteomics projects. In this paper, amino acid composition (20 dimensions) and the dipeptide composition (400 dimensions) were extracted to form the total candidate feature pool (420 dimensions), and each feature was selected into the feature vectors one by one, which were sorted by the absolute value of the correlation coefficient. Finally, we evaluated and recorded the 420 results of Support Vector Machine (SVM) as the prediction engine. According to the results of SVM, the first 208 features were chosen from the 420 dimensions, which were considered as the efficient ones. By analyzing the composition of the former 208 features, we found that the protein solubility was significantly influenced by the occurrence frequencies of the acidic amino acids, basic amino acids, non-polar hydrophobic amino acids and the two polar neutral amino acids(C, Q) in the protein sequences. Additionally, we detected that the dipeptides composed by the acidic amino acids (D, E) and basic amino acids (K, R and H), especially the dipeptide composed by the acidic amino acids (D, E), had strong interconnection with the protein solubility.

  10. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    Science.gov (United States)

    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.

  11. THIN-LAYER SEPARATION OF CITRIC ACID CYCLE INTERMEDIATES, LACTIC ACID, AND THE AMINO ACID TAURINE

    Science.gov (United States)

    This paper describes a two-dimensional mixed-layer method for separating citric acid cycle intermediates, lactic acid and the amino acid taurine. The method cleanly separates all citric acid cycle intermediates tested, excepting citric acid and isocitric acid. The solvents are in...

  12. Stereoselective synthesis of stable-isotope-labeled amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III [Los Alamos National Laboratory, NM (United States); Lodwig, S.N. [Centralia College, WA (United States)

    1994-12-01

    For magnetic resonance and vibrational spectroscopies to reach their full potential, they must be used in combination with sophisticated site-specific stable isotope labeling of biological macromolecules. Labeled amino acids are required for the study of the structure and function of enzymes and proteins. Because there are 20 common amino acids, each with its own distinguishing chemistry, they remain a synthetic challenge. The Oppolzer chiral auxiliary provides a general tool with which to approach the synthesis of labeled amino acids. By using the Oppolzer auxiliary, amino acids can be constructed from several small molecules, which is ideal for stable isotope labeling. In addition to directing the stereochemistry at the {alpha}-carbon, the camphorsultam can be used for stereo-specific isotope labeling at prochiral centers in amino acids. By using the camphorsultam auxiliary we have the potential to synthesize virtually any isotopomer of all of the common amino acids.

  13. Cytokines: muscle protein and amino acid metabolism

    DEFF Research Database (Denmark)

    van Hall, Gerrit

    2012-01-01

    of IL-6 on the regulation of muscle protein metabolism but indirectly via IL-6 reducing amino acid availability. SUMMARY: Recent studies suggest that the best described cytokines TNF-α and IL-6 are unlikely to be the major direct mediators of muscle protein loss in inflammatory diseases. However....... However, this does not seem applicable for inflammatory diseases or human models of sepsis, in which the enhanced imbalance between these two processes is observed within an enhanced, normal or reduced muscle protein turnover.......PURPOSE OF REVIEW: This review highlights the role of cytokines, in particular tumour necrosis factor alpha (TNF-α) and interleukin-6 (IL-6), in relation to the nature of human in-vivo muscle wasting in disease. RECENT FINDINGS: Infusion of human TNF-α and IL-6 in healthy individuals, acutely...

  14. Diversity of amino acids in a typical chernozem of Moldova

    Science.gov (United States)

    Frunze, N. I.

    2014-12-01

    The content and composition of the amino acids in typical chernozems were studied. The objects of the study included a reference soil under an old fallow and three variants under fodder crop rotations: not fertilized, with mineral fertilizers, and with organic fertilizers. The contents of 18 amino acids were determined in these soils. The amino acids were extracted by the method of acid hydrolysis and identified by the method of ion-exchange chromatography. The total content of most of the amino acids was maximal in the reference soil; it was much lower in the cultivated soils and decreased in the following sequence: organic background > mineral background > no fertilization. The diversity of amino acids was evaluated quantitatively using different parameters applied in ecology for estimating various aspects of the species composition of communities (Simpson, Margalef, Menhinick, and Shannon's indices). The diversity and contribution of different amino acids to the total pool of amino acids also varied significantly in the studied variants. The maximum diversity of amino acids and maximum evenness of their relative abundance indices were typical of the reference chernozem; these parameters were lower in the cultivated soils. It was concluded that the changes in the structure of the amino acids under the impact of agricultural loads are similar to those that are usually observed under stress conditions.

  15. The Origin of Amino Acids in Lunar Regolith Samples

    Science.gov (United States)

    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.

  16. Intravenous amino acids in third trimester isolated oligohydramnios

    International Nuclear Information System (INIS)

    To determine the efficacy of maternal administration of intravenous amino acid solution in improving amniotic fluid volume in cases of isolated oligohydramnios and to observe its impact on mode of delivery and neonatal outcome. Study Design: A prospective case series. Methodology: Forty two women with singleton pregnancy, well established gestational age and clinically and sonographically proven isolated oligohydramnios in the third trimester before 36 weeks were administered amino acid solution intravenously after excluding cases of premature rupture of membranes, congenital anomaly of fetus, maternal pulmonary, cardiovascular and hypertensive disorders, and severe placental insufficiency (raised S/D ratio). Pre-infusion and postinfusion Amniotic fluid Index (AFI) was measured and repeated weekly. Women were followed till delivery. Results: According to repeated measurement analysis of variance, mean pre-infusion AFI was 4.7 cm, mean one week postinfusion AFI was 5.8 cm, mean two week post-infusion AFI was 6.2 cm and mean three week AFI was 6.3 cm (p-value 0.029, significant). Cesarean section became a predominant mode of delivery in this group without a firm evidence of associated fetal compromise. Conclusion: Amino acid infusion is an effective therapy for raising AFI in isolated oligohydramnios in this case series. Liberal use of cesarean section in this selected group should be carefully re-evaluated. (author)

  17. A new synthetic protocol for coumarin amino acid

    Directory of Open Access Journals (Sweden)

    Xinyi Xu

    2013-02-01

    Full Text Available The hydrochloride of the racemic amino acid (2-(7-hydroxycoumarin-4-ylethylglycine, which can serve as a fluorescent probe in proteins, and two halogen derivatives of it, were synthesized by using a new synthetic protocol in five steps. It is less costly and relatively easy to prepare this kind of fluorescent amino acid with the new synthetic method. Furthermore, it can be applied to synthesize other derivatives of the coumarin amino acid with some specific properties.

  18. Reconstructing Amino Acid Interaction Networks by an Ant Colony Approach

    OpenAIRE

    Gaci, Omar; Balev, Stefan

    2009-01-01

    In this paper we introduce the notion of protein interaction network. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. We consider the problem of reconstructing protein's interaction network from its amino acid sequence. We rely on a probability that two amino acids interact as a function of their physico-chemical properties coupled to an ant colony system to solve this problem.

  19. Amino acid analysis in biological fluids by GC-MS

    OpenAIRE

    Kaspar, Hannelore

    2009-01-01

    Amino acids are intermediates in cellular metabolism and their quantitative analysis plays an important role in disease diagnostics. A gas chromatography-mass spectrometry (GC-MS) based method was developed for the quantitative analysis of free amino acids as their propyl chloroformate derivatives in biological fluids. Derivatization with propyl chloroformate could be carried out directly in the biological samples without prior protein precipitation or solid-phase extraction of the amino acid...

  20. GLC of amino acids - A survey of contamination.

    Science.gov (United States)

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

    1972-01-01

    Analyses of biological substances and geochemical samples, of both terrestrial and extraterrestrial origin, are reported for amino acids at the 1-10 nanogram per gram level achieved by gas-liquid and ion-exchange chromatographic methods. These studies have shown that nanogram quantities of amino acids, present in water extracts of geochemical samples or in other samples of low amino acid concentration, can be successfully determined only if the researcher is well aware of the possible sources of contamination.

  1. PHARMACOLOGICAL EFFECTS OF SNAKE VENOM L- AMINO ACID OXIDASES

    OpenAIRE

    Joseph Baby; Rajan Sheeja S; M.V Jeevitha; S.U Ajisha

    2011-01-01

    L-Amino acid oxidases are flavoenzymes which catalyze the stereospecific oxidative deamination of an L-amino acid substrate to a corresponding a-ketoacid with hydrogen peroxide and ammonia production. These enzymes, which are widely distributed in many different organisms, exhibit a marked affinity for hydrophobic amino acids, including phenylalanine, tryptophan, tyrosine, and leucine. Snake venom LAAO induces platelet aggregation and cytotoxicity in various cancer cell lines. The enzyme has ...

  2. A Novel Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    ZHANG Zhi-Hui; LI Shuo; XU Pen-gFei

    2003-01-01

    @@ β-hydroxy-α-amino acids constitute an important class of compounds as naturally occurring amino acids and as components of many complex natural products possessing a wide range of biological activities. [1] As a consequence of the essential role played by these amino acids in the biological systems and their utility as synthetic building blocks, a number of useful strategies have been devised for their preparation. [2

  3. Effects of essential amino acids on food and water intake of rats

    OpenAIRE

    Li, ETS; Luo, S; Trigazis, L; Kubis, G; Anderson, GH

    1994-01-01

    This study examined the effects of selected groups of essential amino acids (EAAs), given by gavage, on short-term food and water intake. Amino acid groups were selected on the basis of their common physiologic functions in relation to current hypotheses on the role of amino acids in food intake control, and the quantities given were based on the proportions in 1.5 g of the EAA content of albumin. The complete EAA mixture (1.5 g) suppressed food intake by an average of 60 and 37% during the 1...

  4. Computational Design of Multinuclear Metalloproteins Using Unnatural Amino Acids.

    Science.gov (United States)

    Hansen, William A; Mills, Jeremy H; Khare, Sagar D

    2016-01-01

    Multinuclear metal ion clusters, coordinated by proteins, catalyze various critical biological redox reactions, including water oxidation in photosynthesis, and nitrogen fixation. Designed metalloproteins featuring synthetic metal clusters would aid in the design of bio-inspired catalysts for various applications in synthetic biology. The design of metal ion-binding sites in a protein chain requires geometrically constrained and accurate placement of several (between three and six) polar and/or charged amino acid side chains for every metal ion, making the design problem very challenging to address. Here, we describe a general computational method to redesign oligomeric interfaces of symmetric proteins for the purpose of creating novel multinuclear metalloproteins with tunable geometries, electrochemical environments, and metal cofactor stability via first and second-shell interactions. The method requires a target symmetric organometallic cofactor whose coordinating ligands resemble the side chains of a natural or unnatural amino acid and a library of oligomeric protein structures featuring the same symmetry as the target cofactor. Geometric interface matches between target cofactor and scaffold are determined using a program that we call symmetric protein recursive ion-cofactor sampler (SyPRIS). First, the amino acid-bound organometallic cofactor model is built and symmetrically aligned to the axes of symmetry of each scaffold. Depending on the symmetry, rigid body and inverse rotameric degrees of freedom of the cofactor model are then simultaneously sampled to locate scaffold backbone constellations that are geometrically poised to incorporate the cofactor. Optionally, backbone remodeling of loops can be performed if no perfect matches are identified. Finally, the identities of spatially proximal neighbor residues of the cofactor are optimized using Rosetta Design. Selected designs can then be produced in the laboratory using genetically incorporated unnatural

  5. Design and characterization of auxotrophy-based amino acid biosensors.

    Directory of Open Access Journals (Sweden)

    Felix Bertels

    Full Text Available Efficient and inexpensive methods are required for the high-throughput quantification of amino acids in physiological fluids or microbial cell cultures. Here we develop an array of Escherichia coli biosensors to sensitively quantify eleven different amino acids. By using online databases, genes involved in amino acid biosynthesis were identified that - upon deletion - should render the corresponding mutant auxotrophic for one particular amino acid. This rational design strategy suggested genes involved in the biosynthesis of arginine, histidine, isoleucine, leucine, lysine, methionine, phenylalanine, proline, threonine, tryptophan, and tyrosine as potential genetic targets. A detailed phenotypic characterization of the corresponding single-gene deletion mutants indeed confirmed that these strains could neither grow on a minimal medium lacking amino acids nor transform any other proteinogenic amino acid into the focal one. Site-specific integration of the egfp gene into the chromosome of each biosensor decreased the detection limit of the GFP-labeled cells by 30% relative to turbidometric measurements. Finally, using the biosensors to determine the amino acid concentration in the supernatants of two amino acid overproducing E. coli strains (i.e. ΔhisL and ΔtdcC both turbidometrically and via GFP fluorescence emission and comparing the results to conventional HPLC measurements confirmed the utility of the developed biosensor system. Taken together, our study provides not only a genotypically and phenotypically well-characterized set of publicly available amino acid biosensors, but also demonstrates the feasibility of the rational design strategy used.

  6. Method for Enzyme Design with Genetically Encoded Unnatural Amino Acids.

    Science.gov (United States)

    Hu, C; Wang, J

    2016-01-01

    We describe the methodologies for the design of artificial enzymes with genetically encoded unnatural amino acids. Genetically encoded unnatural amino acids offer great promise for constructing artificial enzymes with novel activities. In our studies, the designs of artificial enzyme were divided into two steps. First, we considered the unnatural amino acids and the protein scaffold separately. The scaffold is designed by traditional protein design methods. The unnatural amino acids are inspired by natural structure and organic chemistry methods, and synthesized by either organic chemistry methods or enzymatic conversion. With the increasing number of published unnatural amino acids with various functions, we described an unnatural amino acids toolkit containing metal chelators, redox mediators, and click chemistry reagents. These efforts enable a researcher to search the toolkit for appropriate unnatural amino acids for the study, rather than design and synthesize the unnatural amino acids from the beginning. After the first step, the model enzyme was optimized by computational methods and directed evolution. Lastly, we describe a general method for evolving aminoacyl-tRNA synthetase and expressing unnatural amino acids incorporated into a protein. PMID:27586330

  7. Analysis of amino acids network based on distance matrix

    Science.gov (United States)

    Ali, Tazid; Akhtar, Adil; Gohain, Nisha

    2016-06-01

    In this paper we have constructed a distance matrix of the amino acids. The distance is defined based on the relative evolutionary importance of the base position of the corresponding codons. From this distance matrix a network of the amino acids is obtained. We have argued that this network depicts the evolutionary pattern of the amino acids. To examine the relative importance of the amino acids with respect to this network we have discussed different measures of centrality. We have also investigated the correlation coefficients between different measures of centrality. Further we have explored clustering coefficient as well as degree of distribution.

  8. Abiotic racemization kinetics of amino acids in marine sediments

    DEFF Research Database (Denmark)

    Steen, Andrew; Jørgensen, Bo Barker; Lomstein, Bente Aagaard

    2013-01-01

    Enantiomeric ratios of amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic racemize abiotically. Based on a heating experiment, we report Arrhenius parameters...... between different amino acids or depths. These results can be used in conjunction with measurements of sediment age to predict the ratio of D:L amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial...

  9. Amino acids in the cultivation of mammalian cells.

    Science.gov (United States)

    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.

  10. Which Amino Acids Should Be Used in Prebiotic Chemistry Studies?

    Science.gov (United States)

    Zaia, Dimas A. M.; Zaia, Cássia Thaïs B. V.; de Santana, Henrique

    2008-12-01

    The adsorption of amino acids on minerals and their condensation under conditions that resemble those of prebiotic earth is a well studied subject. However, which amino acids should be used in these experiments is still an open question. The main goal of this review is to attempt to answer this question. There were two sources of amino acids for the prebiotic earth: (1) exogenous—meaning that the amino acids were synthesized outside the earth and delivered to our planet by interplanetary dust particles (IDPs), meteorites, comets, etc. and (2) endogenous—meaning that they were synthesized on earth in atmospheric mixtures, hydrothermal vents, etc. For prebiotic chemistry studies, the use of a mixture of amino acids from both endogenous and exogenous sources is suggested. The exogenous contribution of amino acids to this mixture is very different from the average composition of proteins, and contains several non-protein amino acids. On the other hand, the mixture of amino acids from endogenous sources is seems to more closely resemble the amino acid composition of terrestrial proteins.

  11. Synthesis of novel fullerene α-amino acid conjugates

    Institute of Scientific and Technical Information of China (English)

    Jing Zhang; Yan Xia Wang; Feng Kang; Ying Ya Shao; Zong Jie Li; Xin Lin Yang

    2008-01-01

    Aspartie acid and glutamic acid with protected α-amino and α-carboxyl groups had been used to react with the activated hydroxyl group of N-substituted 3,4-fuUero pyrrolidine.The products were deprotected,affording two monofullerene α-amino acids,monofullerene aspartic acid(mFas)and monofullerene glutamic acid(mFgu).Then a bifullerene glutamic acid conjugate (bFguC)was synthesized by reaction of mFgu containing protected amino group with N-subsfimted 3,4-fullero pyrrolidine.

  12. Synthesis, Characterization and Structure of Chiral Amino Acids and Their Corresponding Amino Alcohols with Camphoric Backbone

    Institute of Scientific and Technical Information of China (English)

    QIAN Hui-Fen; HUANG Wei; LI Hui-Hui; YAO Cheng

    2006-01-01

    Chiral amino acids and their corresponding amino alcohols bearing camphoric backbone were prepared from D-(+)-camphoric imide and characterized by infrared, elemental analysis, ESI-MS, and NMR measurements. Among them, one intermediate (lS,3R)-3-amino-2,2,3-trimethyl cyclopentane-1-carboxylic acid hydrochloride 3 was structurally elucidated by X-ray diffraction techniques. Versatile intermolecular hydrogen bonding interactions observed in its packing structure result in a two-dimensional framework.

  13. Novel amino acids: synthesis of furoxan and sydnonimine containing amino acids and peptides as potential nitric oxide releasing motifs.

    Science.gov (United States)

    Nortcliffe, Andrew; Botting, Nigel P; O'Hagan, David

    2013-07-28

    The incorporation of furoxan and sydnonimine ring systems into amino acid side chains is demonstrated with the preparation of four novel amino acids which carry these nitric oxide-releasing motifs. N-((4-Nitrophenoxy)carbonyl)-3-phenylsydnonimine 9 and bis(phenylsulfonyl)furoxan 10 are the key intermediates for introducing the heterocycle side chains onto appropriate amine and alcohol functionalities respectively. Furoxan 5 and 7 both displayed NO release based on determination of nitrite production. Orthogonal amino acid protecting group strategies were deployed to demonstrate that the amino acids could be incorporated into peptide frameworks. By way of demonstration the amino acids were placed centrally into several tripeptide motifs. Griess test assays showed that these amino acids released NO in the presence of γ-glutathione (GST). PMID:23753002

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

    Directory of Open Access Journals (Sweden)

    Rafael Pernil

    2015-04-01

    Full Text Available 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.

  15. Bolus ingestion of individual branched-chain amino acids alters plasma amino acid profiles in young healthy men

    OpenAIRE

    Matsumoto, Takuya; Nakamura, Koichi; Matsumoto, Hideki; Sakai, Ryosei; Kuwahara, Tomomi; Kadota, Yoshihiro; Kitaura, Yasuyuki; SATO, JUICHI; Shimomura, Yoshiharu

    2014-01-01

    Physiological conditions in humans affect plasma amino acid profiles that might have potential for medical use. Because the branched-chain amino acids (BCAAs) leucine, isoleucine and valine are used as medicines and supplements, we investigated the acute effects of individual BCAAs (10–90 mg/kg body weight) or mixed BCAAs ingested as a bolus on plasma amino acid profiles in young healthy men. Plasma leucine levels rapidly increased and peaked around 30 min after leucine ingestion. Concentrati...

  16. A single amino acid change within the R2 domain of the VvMYB5b transcription factor modulates affinity for protein partners and target promoters selectivity

    Directory of Open Access Journals (Sweden)

    Granier Thierry

    2011-08-01

    Full Text Available Abstract Background Flavonoid pathway is spatially and temporally controlled during plant development and the transcriptional regulation of the structural genes is mostly orchestrated by a ternary protein complex that involves three classes of transcription factors (R2-R3-MYB, bHLH and WDR. In grapevine (Vitis vinifera L., several MYB transcription factors have been identified but the interactions with their putative bHLH partners to regulate specific branches of the flavonoid pathway are still poorly understood. Results In this work, we describe the effects of a single amino acid substitution (R69L located in the R2 domain of VvMYB5b and predicted to affect the formation of a salt bridge within the protein. The activity of the mutated protein (name VvMYB5bL, the native protein being referred as VvMYB5bR was assessed in different in vivo systems: yeast, grape cell suspensions, and tobacco. In the first two systems, VvMYB5bL exhibited a modified trans-activation capability. Moreover, using yeast two-hybrid assay, we demonstrated that modification of VvMYB5b transcriptional properties impaired its ability to correctly interact with VvMYC1, a grape bHLH protein. These results were further substantiated by overexpression of VvMYB5bR and VvMYB5bL genes in tobacco. Flowers from 35S::VvMYB5bL transgenic plants showed a distinct phenotype in comparison with 35S::VvMYB5bR and the control plants. Finally, significant differences in transcript abundance of flavonoid metabolism genes were observed along with variations in pigments accumulation. Conclusions Taken together, our findings indicate that VvMYB5bL is still able to bind DNA but the structural consequences linked to the mutation affect the capacity of the protein to activate the transcription of some flavonoid genes by modifying the interaction with its co-partner(s. In addition, this study underlines the importance of an internal salt bridge for protein conformation and thus for the establishment

  17. Influence of dietary protein type and iron source on the absorption of amino acids and minerals.

    Science.gov (United States)

    Pérez-Llamas, F; Garaulet, M; Martínez, J A; Marín, J F; Larqué, E; Zamora, S

    2001-12-01

    The apparent digestibility coefficient (ADC) of amino acids and the balance of minerals (calcium, phosphorus, magnesium and iron) has been determined in rats fed four diets differing in the protein type (casein or soy protein) and iron source (ferrous sulphate or lactate) in order to study the possible interactions of these nutrients. The availability of amino acids, especially essential amino acids, was greater in the diet made with animal protein (casein). The iron source also affected the absorption of most amino acids in all the diets assayed with ferrous sulphate being greater. The balance of iron, magnesium and phosphorus was higher in the diets containing animal protein. The retention of calcium and magnesium was significantly greater when ferrous sulphate was used as iron source. These results demonstrate the important interaction between amino acids and minerals and between the minerals themselves, which must be carefully studied when selecting different types of protein or mineral sources in human or animal nutrition.

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

    Energy Technology Data Exchange (ETDEWEB)

    Standaert, Robert F [ORNL; Park, Dr Seung Bum [Seoul National University

    2006-01-01

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

  19. EFFECT OF MICROORGANISMS ON FREE AMINO ACID AND FREE D-AMINO ACID CONTENTS OF VARIOUS DAIRY PRODUCTS

    Directory of Open Access Journals (Sweden)

    Csilla Albert

    2007-06-01

    Full Text Available Free amino acid and free D-amino acid contents of milk samples with different microorganism numbers and composition of dairy products produced from them were examined. Total microorganism number of milk samples examined varied from 1.25x106 to 2.95x106. It was established that concentration of both free D-amino acids and free L-amino acids increased with an increase in microorganism number. However, increase in D-amino acid contents was higher considering its proportion. There was a particularly significant growth in the microorganism number range from 1.5x106 to 2.9x106. Based on analysis of curds and cheese samples produced using different technologies we have come to the conclusion that for fresh dairy products and for those matured over a short time there was a close relation between total microorganism number and free D-amino acid and free L-amino acid contents. At the same time it was found that the ratio of the enantiomers was not affected by the total microorganism number. For dairy products, however, where amino acid production capability of the microbial cultures considerably exceeds, production of microorganisms originally present in the milk raw material, free amino acid contents of the milk product (both D- and L-enantiomers seem to be independent of the composition of milk raw material.

  20. Metal-based chemosensors for amino acids, peptides, and nucleotides

    OpenAIRE

    Buryak, Andrey

    2007-01-01

    An organometallic 4d transition metal complex [Cp*RhCl2]2, together with commercially available dyes, was used to construct indicator displacement assays (IDAs) for the detection of peptides, amino acids, and nucleotides. The combination of the Cp*Rh complex with the dye azophloxine was found to form a chemosensing ensemble for the sequence-selective detection of histidine- and methionine-containing peptides in water at neutral pH. A strong interaction of the rhodium complex with peptides bea...

  1. Metal-based chemosensors for amino acids, peptides, and nucleotides

    OpenAIRE

    Buryak, Andrey; Severin, Kay

    2008-01-01

    An organometallic 4d transition metal complex [Cp*RhCl2]2, together with commercially available dyes, was used to construct indicator displacement assays (IDAs) for the detection of peptides, amino acids, and nucleotides. The combination of the Cp*Rh complex with the dye azophloxine was found to form a chemosensing ensemble for the sequence-selective detection of histidine- and methionine-containing peptides in water at neutral pH. A strong interaction of the rhodium complex with peptides bea...

  2. Peptide Nucleic Acids Having Amino Acid Side Chains

    DEFF Research Database (Denmark)

    1998-01-01

    A novel class of compounds, known as peptide nucleic acids, bind complementary DNA and RNA strands more strongly than the corresponding DNA or RNA strands, and exhibit increased sequence specificity and solubility. The peptide nucleic acids comprise ligands selected from a group consisting of nat...

  3. Inspiration from the mirror: D-amino acid containing peptides in biomedical approaches.

    Science.gov (United States)

    Feng, Zhaoqianqi; Xu, Bing

    2016-06-01

    D-amino acids, the enantiomers of naturally abundant L-amino acids, bear unique stereochemistry properties that lead to the resistance towards most of the endogenous enzymes. Previous works have demonstrated applications of D-amino acids in therapeutic development with the aid of mirror-image phage display and retro-inverso peptide synthesis. In this review, we highlight the recent progress and challenges in the exploration of D-amino acids at the interface of chemistry and life science. First, we will introduce some progress made in traditional application of D-amino acids to enhance biostability of peptide therapeutics. Then, we discuss some works that explore the relatively underexplored interactions between the enzyme and D-amino acids and enzymatic reactions of D-amino acids. To highlight the enzymatic reactions of D-amino acids, we will describe several emerging works on the enzyme-instructed self-assembly (EISA) and their potential application in selective anti-inflammatory or anticancer therapies. At the end, we briefly mention the challenges and possible future directions. PMID:27159920

  4. Photochirogenesis: Photochemical models on the absolute asymmetric formation of amino acids in interstellar space

    Science.gov (United States)

    Meinert, Cornelia; de Marcellus, Pierre; Le Sergeant D'Hendecourt, Louis; Nahon, Laurent; Jones, Nykola C.; Hoffmann, Søren V.; Bredehöft, Jan Hendrik; Meierhenrich, Uwe J.

    2011-10-01

    Proteins of all living organisms including plants, animals, and humans are made up of amino acid monomers that show identical stereochemical L-configuration. Hypotheses for the origin of this symmetry breaking in biomolecules include the absolute asymmetric photochemistry model by which interstellar ultraviolet (UV) circularly polarized light (CPL) induces an enantiomeric excess in chiral organic molecules in the interstellar/circumstellar media. This scenario is supported by a) the detection of amino acids in the organic residues of UV-photo-processed interstellar ice analogues, b) the occurrence of L-enantiomer-enriched amino acids in carbonaceous meteorites, and c) the observation of CPL of the same helicity over large distance scales in the massive star-forming region of Orion. These topics are of high importance in topical biophysical research and will be discussed in this review. Further evidence that amino acids and other molecules of prebiotic interest are asymmetrically formed in space comes from studies on the enantioselective photolysis of amino acids by UV-CPL. Also, experiments have been performed on the absolute asymmetric photochemical synthesis of enantiomer-enriched amino acids from mixtures of astrophysically relevant achiral precursor molecules using UV-circularly polarized photons. Both approaches are based on circular dichroic transitions of amino acids that will be highlighted here as well. These results have strong implications on our current understanding of how life's precursor molecules were possibly built and how life selected the left-handed form of proteinogenic amino acids.

  5. The Path of Carbon in Photosynthesis II. Amino Acids

    Science.gov (United States)

    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.

  6. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    OpenAIRE

    Claude Daneault; Saïd Barazzouk

    2012-01-01

    In this work, oxidized nanocellulose (ONC) was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl) carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, th...

  7. Separation of amino acid enantiomers by micelle-enhanced ultrafiltration

    NARCIS (Netherlands)

    Bruin, de T.J.M.; Marcelis, A.T.M.; Zuilhof, H.; Rodenburg, L.M.; Overdevest, P.E.M.; Padt, van der A.; Sudhölter, E.J.R.

    2000-01-01

    A Micelle-enhanced ultrafiltration (MEUF) separation process was investigated that can potentially be used for large-scale enantioseparations. Copper(II)-amino acid derivatives dissolved in nonionic surfactant micelles were used as chiral selectors for the separation of dilute racemic amino acids so

  8. Interactive Hangman Teaches Amino Acid Structures and Abbreviations

    Science.gov (United States)

    Pennington, Britney O.; Sears, Duane; Clegg, Dennis O.

    2014-01-01

    We developed an interactive exercise to teach students how to draw the structures of the 20 standard amino acids and to identify the one-letter abbreviations by modifying the familiar game of "Hangman." Amino acid structures were used to represent single letters throughout the game. To provide additional practice in identifying…

  9. Ant Colony Approach to Predict Amino Acid Interaction Networks

    OpenAIRE

    Gaci, Omar; Balev, Stefan

    2009-01-01

    In this paper we introduce the notion of protein interaction network. This is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. We consider the problem of reconstructing protein's interaction network from its amino acid sequence. An ant colony approach is used to solve this problem.

  10. Physiological and biochemical studies of bacterial amino acid amide metabolism

    NARCIS (Netherlands)

    Hermes, Hubertus Franciscus Maria

    2008-01-01

    Amino acids represent a class of versatile chiral building blocks for a whole range of fine chemicals, used in the pharmaceutical and agro-chemical industry. Considerable experience currently is available with a wide variety of chemo-enzymatic processes for the synthesis of amino acids, which is app

  11. Natural toxins that affect plant amino acid metabolism

    Science.gov (United States)

    A diverse range of natural compounds interfere with the synthesis and other aspects of amino acid metabolism. Some are amino acid analogues, but most are not. This review covers a number of specific natural phytotoxic compounds by molecular target site. Inhibition of glutamine synthetase is of part...

  12. CO2 sorption by supported amino acid ionic liquids

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention concerns the absorption and desorption behaviour of carbon dioxide (CO2) using ionic liquids derived from amino acids adsorbed on porous carrier materials.......The present invention concerns the absorption and desorption behaviour of carbon dioxide (CO2) using ionic liquids derived from amino acids adsorbed on porous carrier materials....

  13. Site specific incorporation of keto amino acids into proteins

    Science.gov (United States)

    Schultz, Peter G.; Wang, Lei

    2011-03-22

    Compositions and methods of producing components of protein biosynthetic machinery that include orthogonal tRNAs, orthogonal aminoacyl-tRNA synthetases, and orthogonal pairs of tRNAs/synthetases, which incorporate keto amino acids into proteins are provided. Methods for identifying these orthogonal pairs are also provided along with methods of producing proteins with keto amino acids using these orthogonal pairs.

  14. Meteoritic Amino Acids: Diversity in Compositions Reflects Parent Body Histories.

    Science.gov (United States)

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

    2016-06-22

    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

  15. The protein digestibility-corrected amino acid score

    NARCIS (Netherlands)

    Schaafsma, G.

    2000-01-01

    The protein digestibility–corrected amino acid score (PDCAAS) has been adopted by FAO/WHO as the preferred method for the measurement of the protein value in human nutrition. The method is based on comparison of the concentration of the first limiting essential amino acid in the test protein with th

  16. Nitrogen and amino acid metabolism in dairy cows

    NARCIS (Netherlands)

    Tamminga, S.

    1981-01-01

    For the process of milk production, the dairy cow requires nutrients of which energy supplying nutrients and protein or amino acid supplying nutrients are the most important. Amino acid supplying nutrients have to be absorbed from the small intestine and the research reported in this thesis mainly c

  17. A plasma membrane association module in yeast amino acid transporters

    NARCIS (Netherlands)

    Popov-Čeleketić, Dušan; Bianchi, Frans; Ruiz, Stephanie J; Meutiawati, Febrina; Poolman, Bert

    2016-01-01

    Amino acid permeases (AAPs) in the plasma membrane (PM) of Saccharomyces cerevisiae are responsible for the uptake of amino acids and involved in regulation of their cellular levels. Here, we report on a strong and complex module for PM association found in the C-terminal tail of AAPs. Using in sili

  18. Hyperdimensional analysis of amino acid pair distributions in proteins.

    Directory of Open Access Journals (Sweden)

    Svend B Henriksen

    Full Text Available Our manuscript presents a novel approach to protein structure analyses. We have organized an 8-dimensional data cube with protein 3D-structural information from 8706 high-resolution non-redundant protein-chains with the aim of identifying packing rules at the amino acid pair level. The cube contains information about amino acid type, solvent accessibility, spatial and sequence distance, secondary structure and sequence length. We are able to pose structural queries to the data cube using program ProPack. The response is a 1, 2 or 3D graph. Whereas the response is of a statistical nature, the user can obtain an instant list of all PDB-structures where such pair is found. The user may select a particular structure, which is displayed highlighting the pair in question. The user may pose millions of different queries and for each one he will receive the answer in a few seconds. In order to demonstrate the capabilities of the data cube as well as the programs, we have selected well known structural features, disulphide bridges and salt bridges, where we illustrate how the queries are posed, and how answers are given. Motifs involving cysteines such as disulphide bridges, zinc-fingers and iron-sulfur clusters are clearly identified and differentiated. ProPack also reveals that whereas pairs of Lys residues virtually never appear in close spatial proximity, pairs of Arg are abundant and appear at close spatial distance, contrasting the belief that electrostatic repulsion would prevent this juxtaposition and that Arg-Lys is perceived as a conservative mutation. The presented programs can find and visualize novel packing preferences in proteins structures allowing the user to unravel correlations between pairs of amino acids. The new tools allow the user to view statistical information and visualize instantly the structures that underpin the statistical information, which is far from trivial with most other SW tools for protein structure analysis.

  19. Mechanisms controlling renal hemodynamics and electrolyte excretion during amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Woods, L.L.; Mizelle, H.L.; Montani, J.P.; Hall, J.E.

    1986-08-01

    Our purpose was to investigate the mechanisms by which increased plasma amino acids elevate renal blood flow (RBF) and glomerular filtration rate (GFR). Since transport of amino acids and Na is linked in the proximal tubule, the authors hypothesized that increased amino acids might stimulate proximal tubular Na reabsorption (PR/sub Na/) and thus increase RBF and GFR by a macula densa feedback mechanism. A solution of four amino acids (Ala, Ser, Gly, Pro) was infused intravenously into anesthetized dogs with normal kidneys (NK) and with kidneys in which the tubuloglomerular feedback mechanism was blunted by lowering renal artery pressure (LPK) or blocked by making the kidneys nonfiltering (NFK). In NK, RBF and GFR increased by 35 +/- 4% and 30 +/- 7% after 90 min of amino acid infusion, while PR/sub Na/ (estimated from lithium clearance) and O2 consumption increased by 31 +/- 5% and 29 +/- 5% and distal Na delivery remained relatively constant. Autoregulation of RBF and GFR in response to step deceases in renal artery pressure was impaired during amino acids in NK. The hemodynamic responses to amino acids were abolished in LPK and NFK. Infusion of the nonmetabolized -aminoisobutyric acid into NK produced changes in renal hemodynamics that were similar to the responses observed with the four metabolizable amino acids. These data are consistent with the hypothesis that elevation of plasma amino acids increases RBF and GFR by a mechanism that requires an intact macula densa feedback. Metabolism of the amino acids does not appear to be necessary for these changes to occur.

  20. Recommended ingestion of indispensable amino acids to young men . A study using stable isotopes, plasmatic amino acids and nitrogen balance

    International Nuclear Information System (INIS)

    It has been previously stated that the minimum physiological recommendations for the indispensable amino acids in health adults, as proposed by FAO/WHO/UNU in 1985, are far too low, except for the methionine. An amino acid stable isotopic kinetic study was conducted to seek further experimental support to this hypothesis. Twenty healthy young men received an l-amino acid based diet, supplying 140 mg N.kg-1.d-1, patterned on egg protein for 1 week, then for 3 weeks either i) a pattern based on current international recommendations (FAO diet, n=7), ii) a the tentative Laboratory of Human Nutrition of the Massachusetts Institute of Technology, new amino acid recommendation pattern (MIT diet, n=7) or iii) again the egg hen pattern (EGG diet, n=6). All subjects were again studied for one final, consecutive week of the egg diet. At the end of the initial week, at the first and third week with the three experimental diets,and after three days following the return of the egg diet, an 8 h primed continuous intravenous infusion with l-13 C-leucine was conducted (3 h, fast, 5 h fed - while subjects received hourly meals supplying the equivalent of 5/12 total daily intake). Estimation of leucine balance were carried out with measurements plasma free amino acids changes. Daily nitrogen balances were obtained through the study. Interpretation of plasma amino acids profile, and changes of leucine kinetics balances, indicated that the FAO diet was not able to maintain amino acids homeostasis whereas the MIT and the egg diets sustained body amino acids equilibrium with a positive amino acid balance. nitrogen balances tended to be more negative with the FAO diet but failed to show statistically significant differences among the three diets. The finding point out that it would be prudent to use the new, tentative recommended amino acid pattern (MIT diet 0 as the minimum physiological amino acid needs of healthy human adults (author)

  1. Electronic coupling through natural amino acids

    International Nuclear Information System (INIS)

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green’s function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design

  2. Electronic coupling through natural amino acids

    Science.gov (United States)

    Berstis, Laura; Beckham, Gregg T.; Crowley, Michael F.

    2015-12-01

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green's function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  3. Electronic coupling through natural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Berstis, Laura; Beckham, Gregg T., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov; Crowley, Michael F., E-mail: michael.crowley@nrel.gov, E-mail: gregg.beckham@nrel.gov [National Renewable Energy Laboratory, National Bioenergy Center, 15013 Denver West Pkwy, Golden, Colorado 80401 (United States)

    2015-12-14

    Myriad scientific domains concern themselves with biological electron transfer (ET) events that span across vast scales of rate and efficiency through a remarkably fine-tuned integration of amino acid (AA) sequences, electronic structure, dynamics, and environment interactions. Within this intricate scheme, many questions persist as to how proteins modulate electron-tunneling properties. To help elucidate these principles, we develop a model set of peptides representing the common α-helix and β-strand motifs including all natural AAs within implicit protein-environment solvation. Using an effective Hamiltonian strategy with density functional theory, we characterize the electronic coupling through these peptides, furthermore considering side-chain dynamics. For both motifs, predictions consistently show that backbone-mediated electronic coupling is distinctly sensitive to AA type (aliphatic, polar, aromatic, negatively charged and positively charged), and to side-chain orientation. The unique properties of these residues may be employed to design activated, deactivated, or switch-like superexchange pathways. Electronic structure calculations and Green’s function analyses indicate that localized shifts in the electron density along the peptide play a role in modulating these pathways, and further substantiate the experimentally observed behavior of proline residues as superbridges. The distinct sensitivities of tunneling pathways to sequence and conformation revealed in this electronic coupling database help improve our fundamental understanding of the broad diversity of ET reactivity and provide guiding principles for peptide design.

  4. Functional amino acids in nutrition and health.

    Science.gov (United States)

    Wu, Guoyao

    2013-09-01

    The recent years have witnessed growing interest in biochemistry, physiology and nutrition of amino acids (AA) in growth, health and disease of humans and other animals. This results from the discoveries of AA in cell signaling involving protein kinases, G protein-coupled receptors, and gaseous molecules (i.e., NO, CO and H2S). In addition, nutritional studies have shown that dietary supplementation with several AA (e.g., arginine, glutamine, glutamate, leucine, and proline) modulates gene expression, enhances growth of the small intestine and skeletal muscle, or reduces excessive body fat. These seminal findings led to the new concept of functional AA, which are defined as those AA that participate in and regulate key metabolic pathways to improve health, survival, growth, development, lactation, and reproduction of the organisms. Functional AA hold great promise in prevention and treatment of metabolic diseases (e.g., obesity, diabetes, and cardiovascular disorders), intrauterine growth restriction, infertility, intestinal and neurological dysfunction, and infectious disease (including viral infections).

  5. Incretin effect after oral amino Acid ingestion in humans

    DEFF Research Database (Denmark)

    Lindgren, Ola; Pacini, Giovanni; Tura, Andrea;

    2015-01-01

    is also present after amino acid ingestion is not known. OBJECTIVE: The objective of the study was to explore insulin secretion and incretin hormones after oral and iv amino acid administration at matched total amino acid concentrations in healthy subjects. DESIGN: An amino acid mixture (Vaminolac......CONTEXT: The incretin effect is the augmented insulin secretion by oral vs iv glucose at matching glucose levels. We previously demonstrated an augmented insulin secretion when fat is given orally rather than iv, suggesting an incretin effect also after fat. However, whether an incretin effect......) was administered orally or iv at a rate resulting in matching total amino acid concentrations to 12 male volunteers with age 22.5 ± 1.4 years and a body mass index 22.4 ± 1.4 kg/m(2), who had no history of diabetes. MAIN OUTCOME MEASURES: Main outcome measures were area under the 120-minute curve for insulin, C...

  6. Amino acids and osmolarity in honeybee drone haemolymph.

    Science.gov (United States)

    Leonhard, B; Crailsheim, K

    1999-01-01

    In the haemolymph of honeybee drones, concentrations of free amino acids were higher than in worker haemolymph, with different relative proportions of individual amino acids. The overall concentration of free amino acids reached its highest level at the 5th day after adult drone emergence, and after the 9th day only minor changes in the concentration and distribution of free amino acids were observed. This coincides with the age when drones reach sexual maturity and change their feeding behaviour. Levels of essential free amino acids were high during the first 3 days of life and thereafter decreased. Osmolarity was lowest at emergence (334 +/- 42 mOsm), increased until the age of 3 days (423 +/- 32 mOsm) and then stayed generally constant until the 16th day of life. Only 25-day-old drones had significantly higher osmolarity (532 +/- 38 mOsm). The overall change in osmolarity during a drone's lifetime was about 40%. PMID:10524277

  7. Regulation of intestinal protein metabolism by amino acids.

    Science.gov (United States)

    Bertrand, Julien; Goichon, Alexis; Déchelotte, Pierre; Coëffier, Moïse

    2013-09-01

    Gut homeostasis plays a major role in health and may be regulated by quantitative and qualitative food intake. In the intestinal mucosa, an intense renewal of proteins occurs, at approximately 50% per day in humans. In some pathophysiological conditions, protein turnover is altered and may contribute to intestinal or systemic diseases. Amino acids are key effectors of gut protein turnover, both as constituents of proteins and as regulatory molecules limiting intestinal injury and maintaining intestinal functions. Many studies have focused on two amino acids: glutamine, known as the preferential substrate of rapidly dividing cells, and arginine, another conditionally essential amino acid. The effects of glutamine and arginine on protein synthesis appear to be model and condition dependent, as are the involved signaling pathways. The regulation of gut protein degradation by amino acids has been minimally documented until now. This review will examine recent data, helping to better understand how amino acids regulate intestinal protein metabolism, and will explore perspectives for future studies.

  8. Independence divergence-generated binary trees of amino acids.

    Science.gov (United States)

    Tusnády, G E; Tusnády, G; Simon, I

    1995-05-01

    The discovery of the relationship between amino acids is important in terms of the replacement ability, as used in protein engineering homology studies, and gaining a better understanding of the roles which various properties of the residues play in the creation of a unique, stable, 3-D protein structure. Amino acid sequences of proteins edited by evolution are anything but random. The measure of nonrandomness, i.e. the level of editing, can be characterized by an independence divergence value. This parameter is used to generate binary tree relationships between amino acids. The relationships of residues presented in this paper are based on protein building features and not on the physico-chemical characteristics of amino acids. This approach is not biased by the tautology present in all sequence similarity-based relationship studies. The roles which various physico-chemical characteristics play in the determination of the relationships between amino acids are also discussed.

  9. Natural vs. random protein sequences: Discovering combinatorics properties on amino acid words.

    Science.gov (United States)

    Santoni, Daniele; Felici, Giovanni; Vergni, Davide

    2016-02-21

    Casual mutations and natural selection have driven the evolution of protein amino acid sequences that we observe at present in nature. The question about which is the dominant force of proteins evolution is still lacking of an unambiguous answer. Casual mutations tend to randomize protein sequences while, in order to have the correct functionality, one expects that selection mechanisms impose rigid constraints on amino acid sequences. Moreover, one also has to consider that the space of all possible amino acid sequences is so astonishingly large that it could be reasonable to have a well tuned amino acid sequence indistinguishable from a random one. In order to study the possibility to discriminate between random and natural amino acid sequences, we introduce different measures of association between pairs of amino acids in a sequence, and apply them to a dataset of 1047 natural protein sequences and 10,470 random sequences, carefully generated in order to preserve the relative length and amino acid distribution of the natural proteins. We analyze the multidimensional measures with machine learning techniques and show that, to a reasonable extent, natural protein sequences can be differentiated from random ones.

  10. Amino Acid Profile of Some New Vartieties of Oil Seeds

    Directory of Open Access Journals (Sweden)

    Satish Ingale and S.K. Shrivastava

    2011-04-01

    Full Text Available There are large varieties of oil seeds and legumes in India, which are part of traditional food system but whose nutritional and economic values have not been completely determine and are far less exploited for both human and livestock utilization. The objective of this study was to evaluate Sunflower (Helianths annuus LSF-11, Sunflower (Helianths annuus LSF-8, Safflower (Carthamus tinctorius PBNS-12, Safflower (Carthamus tinctorius PBNS-40, and Ground nut (Arachis hypogaea JL-24 seeds with the aim of qualifying and quantifying chemical information that might serve as a guide to exploit its potentials and benefits for human and animal nutrition. The amino acid profile of these oil seed were carried out using standard methods. Amino acid analysis using technical sequential multisampling amino acid analyzer detected all essential and non essential amino acids. The seeds are rich in four amino acids (EAA and NEAA (g/16g N Glutamic acid (5.083, Aspartic acid (3.459, Proline (6.412 and Methionine (3.001%, respectively. The other amino acids compared well with the FAO reference protein, Serine appeared to be the most limiting amino acid percent. Based on results of this study, the lesser known and under-utilized oil seeds, they can be a potential source and energy supplements in livestock feed.

  11. Elevated amniotic fluid amino acid levels in fetuses with gastroschisis

    Directory of Open Access Journals (Sweden)

    A. Kale

    2006-08-01

    Full Text Available Our objective was to measure maternal plasma and amniotic fluid amino acid concentrations in pregnant women diagnosed as having fetuses with gastroschisis in the second trimester of pregnancy. Twenty-one pregnant women who had fetuses with gastroschisis detected by ultrasonography (gastroschisis group in the second trimester and 32 women who had abnormal triple screenings indicating an increased risk for Down syndrome but had healthy fetuses (control group were enrolled in the study. Amniotic fluid was obtained by amniocentesis, and maternal plasma samples were taken simultaneously. The chromosomal analysis of the study and control groups was normal. Levels of free amino acids and non-essential amino acids were measured in plasma and amniotic fluid samples using EZ:fast kits (EZ:fast GC/FID free (physiological amino acid kit by gas chromatography (Focus GC AI 3000 Thermo Finnigan analyzer. The mean levels of essential amino acids (histidine, isoleucine, leucine, lysine, methionine, phenylalanine, threonine, tryptophan, and valine and non-essential amino acids (alanine, glycine, proline, and tyrosine in amniotic fluid were found to be significantly higher in fetuses with gastroschisis than in the control group (P < 0.05. A significant positive correlation between maternal plasma and amniotic fluid concentrations of essential and nonessential amino acids was found only in the gastroschisis group (P < 0.05. The detection of significantly higher amino acid concentrations in the amniotic fluid of fetuses with a gastroschisis defect than in healthy fetuses suggests the occurrence of amino acid malabsorption or of amino acid leakage from the fetus into amniotic fluid.

  12. Excretion of amino acids by humans during space flight

    Science.gov (United States)

    Stein, T. P.; Schluter, M. D.

    1998-01-01

    We measured the urine amino acid distribution patterns before, during and after space flight on the Space Shuttle. The urine samples were collected on two separate flights of the space shuttle. The first flight lasted 9.5 days and the second flight 15 days. Urine was collected continuously on 8 subjects for the period beginning 10 d before launch to 6 d after landing. Results: In contrast to the earlier Skylab missions where a pronounced amino aciduria was found, on shuttle the urinary amino acids showed little change with spaceflight except for a marked decrease in all of the amino acids on FD (flight day) 1 (pvaline on FD3 and FD4 (p<0.05). Conclusions: (i) Amino aciduria is not an inevitable consequence of space flight. (ii) The occurrence of amino aciduria, like muscle protein breakdown is a mission specific effect rather than part of the general human response to microgravity.

  13. Molecular basis for amino acid sensing by family C G-protein-coupled receptors

    DEFF Research Database (Denmark)

    Wellendorph, Petrine; Bräuner-Osborne, Hans

    2009-01-01

    -alpha;-amino acid receptor G-protein-coupled receptor family C, group 6, subtype A (GPRC6A) and seven orphan receptors. Aside from the orphan receptors, the family C GPCRs are dimeric receptors characterized by a large extracellular Venus flytrap domain which bind the endogenous agonists. Except from the GABA(B1......-2) and T1R2-3 receptor, all receptors are either activated or positively modulated by amino acids. In this review, we outline mutational, biophysical and structural studies which have elucidated the interaction of the amino acids with the Venus flytrap domains, molecular mechanisms of receptor selectivity...

  14. Non-protein amino acids in peptide design

    Indian Academy of Sciences (India)

    S Aravinda; N Shamala; Rituparna S Roy; P Balaram

    2003-10-01

    An overview of the use of non-protein amino acids in the design of conformationally well-defined peptides, based on work from the author’s laboratory, is discussed. The crystal structures of several designed oligopeptides illustrate the use -aminoisobutyric acid (Aib) in the construction of helices, D-amino acids in the design of helix termination segments and DPro-Xxx segments for nucleating of -hairpin structures. - and -amino acid residues have been used to expand the range of designed polypeptide structures.

  15. Use of fuzzy clustering technique and matrices to classify amino acids and its impact to Chou's pseudo amino acid composition

    OpenAIRE

    Georgiou, D. N.; Karakasidis, T.E.; Nieto, J J; Torres, A.

    2009-01-01

    Use of fuzzy clustering technique and matrices to classify amino acids and its impact to Chou's pseudo amino acid composition correspondence: Corresponding author. Tel.: +302421074163. (Karakasidis, T.E.) (Karakasidis, T.E.) University of Patras, Department of Mathematics - 265 00 Patras--> - GREECE (Georgiou, D.N.) University of Thessaly, Department of Civil Engineering - 383 34 Volos--> - GREECE (Karakas...

  16. Quantitative analysis of 17 amino acids in tobacco leaves using an amino acid analyzer and chemometric resolution.

    Science.gov (United States)

    Zeng, Yihang; Cai, Wensheng; Shao, Xueguang

    2015-06-01

    A method was developed for quantifying 17 amino acids in tobacco leaves by using an A300 amino acid analyzer and chemometric resolution. In the method, amino acids were eluted by the buffer solution on an ion-exchange column. After reacting with ninhydrin, the derivatives of amino acids were detected by ultraviolet detection. Most amino acids are separated by the elution program. However, five peaks of the derivatives are still overlapping. A non-negative immune algorithm was employed to extract the profiles of the derivatives from the overlapping signals, and then peak areas were adopted for quantitative analysis of the amino acids. The method was validated by the determination of amino acids in tobacco leaves. The relative standard deviations (n = 5) are all less than 2.54% and the recoveries of the spiked samples are in a range of 94.62-108.21%. The feasibility of the method was proved by analyzing the 17 amino acids in 30 tobacco leaf samples.

  17. The putative Cationic Amino acid Transporter 9 is targeted to vesicles and may be involved in plant amino acid homeostasis

    Directory of Open Access Journals (Sweden)

    Huaiyu eYang

    2015-04-01

    Full Text Available Amino acids are major primary metabolites. Their uptake, translocation, compartmentation and re-mobilization require a diverse set of cellular transporters. Here, the broadly expressed gene product of CATIONIC AMINO ACID TRANSPORTER 9 (CAT9 was identified as mainly localized to vesicular membranes that are involved in vacuolar trafficking, including those of the trans-Golgi network. In order to probe whether and how these compartments are involved in amino acid homeostasis, a loss-of-function cat9-1 mutant and ectopic over-expressor plants were isolated. Under restricted nitrogen supply in soil, cat9-1 showed a chlorotic phenotype, which was reversed in the over-expressors. The total soluble amino acid pools were affected in the mutants, but this was only significant under poor nitrogen supply. Upon nitrogen starvation, the major soluble amino acid leaf pools decreased. This decrease was lower in cat9-1 and augmented in the over-expressor. Over-expression generally affected total soluble amino acid concentrations and finally improved the survival upon severe nitrogen starvation. The results potentially identify a novel function of vesicular amino acid transport mediated by CAT9 in the cellular nitrogen-dependent amino acid homeostasis.

  18. Subcritical Water Extraction of Amino Acids from Atacama Desert Soils

    Science.gov (United States)

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

    2007-01-01

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

  19. Organometallic and Bioorganometallic Chemistry – Ferrocene Amino Acids

    Directory of Open Access Journals (Sweden)

    Barišić, L.

    2012-01-01

    Full Text Available This article is the second part of a series dealing with organometallic and bioorganometallic chemistry. In the first part of this series a short review on the history and development of these disciplines was given, emphasizing the importance and scope of bioorganometallic chemistry as a new field dealing with conjugates of organometallics and biomolecules (DNA, PNA, amino acids, peptides.... From the variety of biorganometallics, syntheses and properties of simple conjugates of ferrocene with natural amino acids/peptides were elaborated inter alia. This material is the basis for the second part in which ferrocene amino acids are described. The introduction presents nonproteinogenic alicyclic and aromatic amino acids as the models for the title compounds. Naturally occurring amino acids labelled with ferrocene moiety mostly retain properties of the biomolecules included. Contrary to these ω-ferrocenylamino acids, one could imagine specific amino acids with inserted ferrocene core belonging to either homo- or heterodisubstituted type. The central part of this article is devoted to our investigations of the second type - H2N-(CH2m-Fn-(CH2n-COOH. The general rational procedure for synthesis of these compounds and of their N- and/or C-protected derivatives via the azide intermediates N3-CO-(CH2m- Fn-(CH2n-COOMe has been described. In the solid state derivatives of ferrocene amino acids contain intermolecular hydrogen bonds giving dimeric structures, three-dimensional networks or endless helical chains. The solutions of homologues Ac-NH-(CH2m-Fn-(CH2n-COOMe in nonpolar solvents are dominated by open form conformers. Compounds containing 2–3 ferrocene cores connected by amide, imide and oxalamide spacers were prepared by oligomerization of 1'-aminoferrocene-1-carboxylic acid (Fca or by its condensation with the appropriate reagents. Similar to natural amino acids, ferrocene amino acids are water-soluble substances with high melting points

  20. Graphdiyne as a promising material for detecting amino acids

    Science.gov (United States)

    Chen, Xi; Gao, Pengfei; Guo, Lei; Zhang, Shengli

    2015-11-01

    The adsorption of glycine, glutamic acid, histidine and phenylalanine on single-layer graphdiyne/ graphene is investigated by ab initio calculations. The results show that for each amino acid molecule, the adsorption energy on graphdiyne is larger than the adsorption energy on graphene and dispersion interactions predominate in the adsorption. Molecular dynamics simulations reveal that at room temperature the amino acid molecules keep migrating and rotating on graphdiyne surface and induce fluctuation in graphdiyne bandgap. Additionally, the photon absorption spectra of graphdiyne-amino-acid systems are investigated. We uncover that the presence of amino acid molecules makes the photon absorption peaks of graphdiyne significantly depressed and shifted. Finally, quantum electronic transport properties of graphdiyne-amino-acid systems are compared with the transport properties of pure graphdiyne. We reveal that the amino acid molecules induce distinct changes in the electronic conductivity of graphdiyne. The results in this paper reveal that graphdiyne is a promising two-dimensional material for sensitively detecting amino acids and may potentially be used in biosensors.

  1. Novel class of amino acid antagonists at non-N-methyl-D-aspartic acid excitatory amino acid receptors. Synthesis, in vitro and in vivo pharmacology, and neuroprotection

    Energy Technology Data Exchange (ETDEWEB)

    Krogsgaard-Larsen, P.; Ferkany, J.W.; Nielsen, E.O.; Madsen, U.; Ebert, B.; Johansen, J.S.; Diemer, N.H.; Bruhn, T.; Beattie, D.T.; Curtis, D.R. (Royal Danish School of Pharmacy, Copenhagen (Denmark))

    1991-01-01

    The isoxazole amino acid 2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl) propionic acid (AMPA) (1), which is a highly selective agonist at the AMPA subtype of excitatory amino acid (EAA) receptors, has been used as a lead for the development of two novel EAA receptor antagonists. One of the compounds, 2-amino-3-(3-(carboxymethoxy)-5-methylisoxazol-4-yl)propionic acid (AMOA, 7), was synthesized via O-alkylation by ethyl chloroacetate of the amino acid protected AMPA derivative 4. The other compound, 2-amino-3-(2-(3-hydroxy-5-methylisoxazol-4-yl)-methyl-5-methyl-3-+ ++oxoisoxazolin -4-yl)propionic acid (AMNH, 14) was synthesized with use of 4-(chloromethyl)-3-methoxy-5-methylisoxazole (8) as the starting material. The intermediate 4-(chloromethyl)-2-(3-methoxy-5-methylisoxazol-4-yl)methyl-5-me thylisoxazolin- 3-one (11) was converted into the acetamidomalonate (12), which was stepwise deprotected to give 14. Compounds 7 and 14 were stable in aqueous solution at pH values close to physiological pH. Neither 7 nor 14 showed detectable affinities for the receptor, ion channel, or modulatory sites of the N-methyl-D-aspartic acid (NMDA) receptor complex. Quantitative receptor autoradiographic and conventional binding techniques were used to study the affinities of 7 and 14 for non-NMDA receptor sites. Both compounds were inhibitors of the binding of (3H)AMPA (IC50 = 90 and 29 microM, respectively). Compounds 14 and 7 were both very weak inhibitors of the high-affinity binding of radioactive kainic acid ((3H)KAIN). Compound 14, but not 7, was, however, shown to be an inhibitor of low-affinity (3H)KAIN binding as determined in the presence of 100 mM calcium chloride. In the rat cortical slice preparation, 7 was shown to antagonize excitation induced by 1 with some selectivity, whereas 14 proved to be a rather selective antagonist of KAIN-induced excitation.

  2. Amino acid profiles and digestible indispensable amino acid scores of proteins from the prioritized key foods in Bangladesh.

    Science.gov (United States)

    Shaheen, Nazma; Islam, Saiful; Munmun, Sarah; Mohiduzzaman, Md; Longvah, Thingnganing

    2016-12-15

    Concentrations of standard amino acids were determined in the composite samples (representing 30 agro-ecological zones of Bangladesh) of six prioritized key dietary protein sources: Oryza sativa (rice), Triticum aestivum (wheat flour), Lens culinaris (lentils), Pangusius pangusius (pangas), Labeo rohita (rohu) and Oreochromis mossambicus (tilapia). Digestible indispensable amino acid scores (DIAAS) was calculated using published data on amino acids' digestibility to evaluate the protein quality of these foods. Indispensable amino acid (IAA) contents (mg IAA/g protein), found to be highest in pangas (430) and lowest in wheat (336), of all these analyzed foods exceeded the FAO recommended daily allowance (277mg IAA/g protein) and contributed on average 40% to total amino acid contents. Untruncated DIAAS values ranged from 51% (lysine) in wheat to 106% (histidine) in pangas and distinguished pangas, rohu, and tilapia containing 'excellent quality' protein (DIAAS>100%) with potential to complement lower quality protein of cereals, fruits, and vegetables. PMID:27451158

  3. Amino Acid Synthesis in a Supercritical Carbon Dioxide - Water System

    Directory of Open Access Journals (Sweden)

    Akiyoshi Hoshino

    2009-06-01

    Full Text Available Mars is a CO2-abundant planet, whereas early Earth is thought to be also CO2-abundant. In addition, water was also discovered on Mars in 2008. From the facts and theory, we assumed that soda fountains were present on both planets, and this affected amino acid synthesis. Here, using a supercritical CO2/liquid H2O (10:1 system which mimicked crust soda fountains, we demonstrate production of amino acids from hydroxylamine (nitrogen source and keto acids (oxylic acid sources. In this research, several amino acids were detected with an amino acid analyzer. Moreover, alanine polymers were detected with LC-MS. Our research lights up a new pathway in the study of life’s origin.

  4. Specific amino acids inhibit food intake via the area postrema or vagal afferents.

    Science.gov (United States)

    Jordi, Josua; Herzog, Brigitte; Camargo, Simone M R; Boyle, Christina N; Lutz, Thomas A; Verrey, François

    2013-11-15

    To maintain nutrient homeostasis the central nervous system integrates signals that promote or inhibit eating. The supply of vital amino acids is tuned by adjusting food intake according to its dietary protein content. We hypothesized that this effect is based on the sensing of individual amino acids as a signal to control food intake. Here, we show that food intake was most potently reduced by oral L-arginine (Arg), L-lysine (Lys) and L-glutamic acid (Glu) compared to all other 17 proteogenic amino acids in rats. These three amino acids induced neuronal activity in the area postrema and the nucleus of the solitary tract. Surgical lesion of the area postrema abolished the anorectic response to Arg and Glu, whereas vagal afferent lesion prevented the response to Lys. These three amino acids also provoked gastric distension by differentially altering gastric secretion and/or emptying. Importantly, these peripheral mechanical vagal stimuli were dissociated from the amino acids' effect on food intake. Thus, Arg, Lys and Glu had a selective impact on food processing and intake suggesting them as direct sensory input to assess dietary protein content and quality in vivo. Overall, this study reveals novel amino acid-specific mechanisms for the control of food intake and of gastrointestinal function.

  5. Amino Acid and Peptide Immobilization on Oxidized Nanocellulose: Spectroscopic Characterization

    Directory of Open Access Journals (Sweden)

    Claude Daneault

    2012-06-01

    Full Text Available In this work, oxidized nanocellulose (ONC was synthesized and chemically coupled with amino acids and peptides using a two step coupling method at room temperature. First, ONC was activated by N-ethyl-N’-(3-dimethylaminopropyl carbodiimide hydrochloride, forming a stable active ester in the presence of N-hydroxysuccinimide. Second, the active ester was reacted with the amino group of the amino acid or peptide, forming an amide bond between ONC and the grafted molecule. Using this method, the intermolecular interaction of amino acids and peptides was avoided and uniform coupling of these molecules on ONC was achieved. The coupling reaction was very fast in mild conditions and without alteration of the polysaccharide. The coupling products (ONC-amino acids and ONC-peptides were characterized by transmission electron microscopy and by the absorption, emission, Fourier transform infrared spectroscopy (FTIR and X-ray photoelectron spectroscopy (XPS spectroscopic techniques.

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

    Science.gov (United States)

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

    1988-05-01

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

  7. Conformational Interconversions of Amino Acid Derivatives.

    Science.gov (United States)

    Kaminský, Jakub; Jensen, Frank

    2016-02-01

    Exhaustive conformational interconversions including transition structure analyses of N-acetyl-l-glycine-N-methylamide as well as its alanine, serine, and cysteine analogues have been investigated at the MP2/6-31G** level, yielding a total of 142 transition states. Improved estimates of relative energies were obtained by separately extrapolating the Hartree-Fock and MP2 energies to the basis set limit and adding the difference between CCSD(T) and MP2 results with the cc-pVDZ basis set to the extrapolated MP2 results. The performance of eight empirical force fields (AMBER94, AMBER14SB, MM2, MM3, MMFFs, CHARMM22_CMAP, OPLS_2005, and AMOEBAPRO13) in reproducing ab initio energies of transition states was tested. Our results indicate that commonly used class I force fields employing a fixed partial charge model for the electrostatic interaction provide mean errors in the ∼10 kJ/mol range for energies of conformational transition states for amino acid conformers. Modern reparametrized versions, such as CHARMM22_CMAP, and polarizable force fields, such as AMOEBAPRO13, have slightly lower mean errors, but maximal errors are still in the 35 kJ/mol range. There are differences between the force fields in their ability for reproducing conformational transitions classified according to backbone/side-chain or regions in the Ramachandran angles, but the data set is likely too small to draw any general conclusions. Errors in conformational interconversion barriers by ∼10 kJ/mol suggest that the commonly used force field may bias certain types of transitions by several orders of magnitude in rate and thus lead to incorrect dynamics in simulations. It is therefore suggested that information for conformational transition states should be included in parametrizations of new force fields. PMID:26691979

  8. Non-Natural and Photo-Reactive Amino Acids as Biochemical Probes of Immune Function

    OpenAIRE

    Marta Gómez-Nuñez; Haro, Kurtis J.; Tao Dao; Deming Chau; Annie Won; Sindy Escobar-Alvarez; Victoriya Zakhaleva; Tatyana Korontsvit; Gin, David Y.; Scheinberg, David A.

    2008-01-01

    Wilms tumor protein (WT1) is a transcription factor selectively overexpressed in leukemias and cancers; clinical trials are underway that use altered WT1 peptide sequences as vaccines. Here we report a strategy to study peptide-MHC interactions by incorporating non-natural and photo-reactive amino acids into the sequence of WT1 peptides. Thirteen WT1 peptides sequences were synthesized with chemically modified amino acids (via fluorination and photo-reactive group additions) at MHC and T cell...

  9. Biomarkers in sediments. The racemization/epiremitation of amino acids like tool in geochronology and paleothermometrics

    International Nuclear Information System (INIS)

    The study of amino acids as biomarkers in sediments has become a necessary methodology and tool for the analysis of palaeoenvironmental conditions and, therefore, of climatic evolution in the past. Research based on the selection and analysis of geological biomarkers, and more specifically activities relating to the racemization/epimerization of amino acids, makes it possible to obtain the geochronological and photoelectrochemical data required to establish different hypotheses for Long-Term Performance Assessment of a repository for high level radioactive wastes

  10. Photochirogenesis: Photochemical models on the absolute asymmetric formation of amino acids in interstellar space

    DEFF Research Database (Denmark)

    Meinert, Cornelia; de Marcellus, Pierre; Le Sergeant d'Hendecourt, Louis;

    2011-01-01

    Proteins of all living organisms including plants, animals, and humans are made up of amino acid monomers that show identical stereochemical L-configuration. Hypotheses for the origin of this symmetry breaking in biomolecules include the absolute asymmetric photochemistry model by which interstel...... of how life’s precursor molecules were possibly built and how life selected the left-handed form of proteinogenic amino acids....

  11. Microbial Products Trigger Amino Acid Exudation from Plant Roots1

    Science.gov (United States)

    Phillips, Donald A.; Fox, Tama C.; King, Maria D.; Bhuvaneswari, T.V.; Teuber, Larry R.

    2004-01-01

    Plants naturally cycle amino acids across root cell plasma membranes, and any net efflux is termed exudation. The dominant ecological view is that microorganisms and roots passively compete for amino acids in the soil solution, yet the innate capacity of roots to recover amino acids present in ecologically relevant concentrations is unknown. We find that, in the absence of culturable microorganisms, the influx rates of 16 amino acids (each supplied at 2.5 μm) exceed efflux rates by 5% to 545% in roots of alfalfa (Medicago sativa), Medicago truncatula, maize (Zea mays), and wheat (Triticum aestivum). Several microbial products, which are produced by common soil microorganisms such as Pseudomonas bacteria and Fusarium fungi, significantly enhanced the net efflux (i.e. exudation) of amino acids from roots of these four plant species. In alfalfa, treating roots with 200 μm phenazine, 2,4-diacetylphloroglucinol, or zearalenone increased total net efflux of 16 amino acids 200% to 2,600% in 3 h. Data from 15N tests suggest that 2,4-diacetylphloroglucinol blocks amino acid uptake, whereas zearalenone enhances efflux. Thus, amino acid exudation under normal conditions is a phenomenon that probably reflects both active manipulation and passive uptake by microorganisms, as well as diffusion and adsorption to soil, all of which help overcome the innate capacity of plant roots to reabsorb amino acids. The importance of identifying potential enhancers of root exudation lies in understanding that such compounds may represent regulatory linkages between the larger soil food web and the internal carbon metabolism of the plant. PMID:15347793

  12. Efficient optical resolution of amino acid by alanine racemaze chiral analogue supported on mesoporous carbon

    Science.gov (United States)

    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.

  13. Exhaustive Database Searching for Amino Acid Mutations in Proteomes

    Energy Technology Data Exchange (ETDEWEB)

    Hyatt, Philip Douglas [ORNL; Pan, Chongle [ORNL

    2012-01-01

    Amino acid mutations in proteins can be found by searching tandem mass spectra acquired in shotgun proteomics experiments against protein sequences predicted from genomes. Traditionally, unconstrained searches for amino acid mutations have been accomplished by using a sequence tagging approach that combines de novo sequencing with database searching. However, this approach is limited by the performance of de novo sequencing. The Sipros algorithm v2.0 was developed to perform unconstrained database searching using high-resolution tandem mass spectra by exhaustively enumerating all single non-isobaric mutations for every residue in a protein database. The performance of Sipros for amino acid mutation identification exceeded that of an established sequence tagging algorithm, Inspect, based on benchmarking results from a Rhodopseudomonas palustris proteomics dataset. To demonstrate the viability of the algorithm for meta-proteomics, Sipros was used to identify amino acid mutations in a natural microbial community in acid mine drainage.

  14. The origin of amino acids in lunar regolith samples

    Science.gov (United States)

    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

  15. EFFECT OF TETRACYCLINES ON THE INTRACELLULAR AMINO ACIDS OF MOLDS.

    Science.gov (United States)

    FREEMAN, B A; CIRCO, R

    1963-07-01

    Freeman, Bob A. (University of Chicago, Chicago, Ill.) and Richard Circo. Effect of tetracyclines on the intracellular amino acids of molds. J. Bacteriol. 86:38-44. 1963.-The tetracycline antibiotics were shown to alter the amino acid metabolism of molds whose growth is not markedly affected. Eight molds were grown in the presence of these antiobiotics; four exhibited a general reduction in the concentration of the intracellular amino acids, except for glutamic acid and alanine. In most of these four cultures, the tetracyclines also caused the complete disappearance of arginine, lysine, proline, phenylalanine, and tyrosine from the intracellular amino acid pool. The significance of these observations and the usefulness of the method in the study of the mechanisms of antibiotic action are discussed. PMID:14051820

  16. Digestible indispensable amino acid score and digestible amino acids in eight cereal grains.

    Science.gov (United States)

    Cervantes-Pahm, Sarah K; Liu, Yanhong; Stein, Hans H

    2014-05-01

    To determine values for the digestible indispensable amino acid score (DIAAS), it is recommended that ileal amino acid (AA) digestibility values obtained in growing pigs are used to characterise protein quality in different foods. Therefore, an experiment was conducted to determine the standardised ileal digestibility (SID) of AA in eight cereal grains (yellow dent maize, Nutridense maize, dehulled barley, dehulled oats, polished white rice, rye, sorghum and wheat) fed to pigs, where SID values in pigs can be used to calculate approximate DIAAS values in humans. In the present experiment, twenty-four barrows with a T-cannula inserted in the distal ileum were allotted to eight diets and fed for three periods to give a total of nine replicate pigs per diet. Each period lasted 14 d, and ileal digesta samples were collected on days 13 and 14. Among the SID values obtained for all cereal grains, values for total indispensable AA were greatest (Poats, but greater (Pcereal grains, and the concentrations of SID indispensable AA in Nutridense maize were greater (Pcereal grains, except rye. In conclusion, results indicate that to meet dietary requirements for AA in humans, diets based on yellow dent maize or sorghum require more AA supplementation than diets based on other cereal grains.

  17. Metabolic Response of Pakchoi Leaves to Amino Acid Nitrogen

    Institute of Scientific and Technical Information of China (English)

    WANG Xiao-li; YU Wen-juan; ZHOU Qian; HAN Rui-feng; HUANG Dan-feng

    2014-01-01

    Different nitrogen (N) forms may cause changes in the metabolic profiles of plants. However, few studies have been conducted on the effects of amino acid-N on plant metabolic proifles. The main objective of this study was to identify primary metabolites associated with amino acid-N (Gly, Gln and Ala) through metabolic proifle analysis using gas chromatography-mass spectrometry (GC-MS). Plants of pakchoi (Brassica campestris L. ssp. chinensis L.), Huawang and Wuyueman cultivars, were grown with different nitrogen forms (i.e., Gly, Gln, Ala, NO3--N, and N starvation) applied under sterile hydroponic conditions. The fresh weight and plant N accumulation of Huawang were greater than those of Wuyueman, which indicates that the former exhibited better N-use efficiency than the latter. The physiological performances of the applied N forms were generally in the order of NO3--N>Gln>Gly>Ala. The metabolic analysis of leaf polar extracts revealed 30 amino acid N-responsive metabolites in the two pakchoi cultivars, mainly consisting of sugars, amino acids, and organic acids. Changes in the carbon metabolism of pakchoi leaves under amino acid treatments occurred via the accumulation of fructose, glucose, xylose, and arabinose. Disruption of amino acid metabolism resulted in accumulation of endogenous Gly in Gly treatment, Pro in Ala treatment, and Asn in three amino acid (Gly, Gln and Ala) treatments. By contrast, the levels of endogenous Gln and Leu decreased. However, this reduction varied among cultivars and amino acid types. Amino acid-N supply also affected the citric acid cycle, namely, the second stage of respiration, where leaves in Gly, Gln and Ala treatments contained low levels of malic, citric and succinic acids compared with leaves in NO3--N treatments. No signiifcant difference in the metabolic responses was observed between the two cultivars which differed in their capability to use N. The response of primary metabolites in pakchoi leaves to amino acid-N supply

  18. Uptake of Branched-Chain Amino Acids by Streptococcus thermophilus

    OpenAIRE

    Akpemado, K. M.; Bracquart, P. A.

    1983-01-01

    The transport of branched-chain amino acids in Streptococcus thermophilus was energy dependent. The metabolic inhibitors of glycolysis and ATPase enzymes were active, but the proton-conducting uncouplers were not. Transport was optimal at temperatures of between 30 and 45°C and at pH 7.0 for the three amino acids leucine, valine, and isoleucine; a second peak existed at pH 5.0 with valine and isoleucine. By competition and kinetics studies, the branched-chain amino acids were found to share a...

  19. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    Energy Technology Data Exchange (ETDEWEB)

    Nan, Alexandrina, E-mail: alexandrina.nan@itim-cj.ro; Bunge, Alexander; Turcu, Rodica [National Institute for Research and Development of Isotopic and Molecular Technologies, 67-103 Donat, 400293 Cluj-Napoca (Romania)

    2015-12-23

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  20. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    Science.gov (United States)

    Nan, Alexandrina; Bunge, Alexander; Turcu, Rodica

    2015-12-01

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements.

  1. Hybride magnetic nanostructure based on amino acids functionalized polypyrrole

    International Nuclear Information System (INIS)

    Conducting polypyrrole is especially promising for many commercial applications because of its unique optical, electric, thermal and mechanical properties. We report the synthesis and characterization of novel pyrrole functionalized monomers and core-shell hybrid nanostructures, consisting of a conjugated polymer layer (amino acids functionalized pyrrole copolymers) and a magnetic nanoparticle core. For functionalization of the pyrrole monomer we used several amino acids: tryptophan, leucine, phenylalanine, serine and tyrosine. These amino acids were linked via different types of hydrophobic linkers to the nitrogen atom of the pyrrole monomer. The magnetic core-shell hybrid nanostructures are characterized by various methods such as FTIR spectroscopy, transmission electron microscopy (TEM) and magnetic measurements

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

    Science.gov (United States)

    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. PMID:27224739

  3. VUV state-selected photoionization of thermally-desorbed biomolecules by coupling an aerosol source to an imaging photoelectron/photoion coincidence spectrometer: case of the amino acids tryptophan and phenylalanine.

    Science.gov (United States)

    Gaie-Levrel, François; Garcia, Gustavo A; Schwell, Martin; Nahon, Laurent

    2011-04-21

    Gas phase studies of biological molecules provide structural and dynamical information on isolated systems. The lack of inter- or intra-molecular interactions facilitates the interpretation of the experimental results through theoretical calculations, and constitutes an informative complement to the condensed phase. However advances in the field are partially hindered by the difficulty of vaporising these systems, most of which are thermally unstable. In this work we present a newly developed aerosol mass thermodesorption setup, which has been coupled to a Velocity Map Imaging (VMI) analyzer operated in coincidence with a Wiley-McLaren Time of Flight spectrometer, using synchrotron radiation as a single photon ionization source. Although it has been previously demonstrated that thermolabile molecules such as amino acids can be produced intact by the aerosol vaporisation technique, we show how its non-trivial coupling to a VMI analyzer plus the use of electron/ion coincidences greatly improves the concept in terms of the amount of spectroscopic and dynamic information that can be extracted. In this manner, we report on the valence shell ionization of two amino acids, tryptophan and phenylalanine, for which threshold photoelectron spectra have been recorded within the first 3 eV above the first ionization energy using synchrotron radiation emitted from the DESIRS beamline located at SOLEIL in France. Their adiabatic ionization energies (IEs) have been measured at 7.40 ± 0.05 and 8.65 ± 0.02 eV, respectively, and their spectra analyzed using existing theoretical data from the literature. The IE values agree well with previously published ones, but are given here with a considerably reduced uncertainty by up to a factor of 5. The photostability of both amino acids is also described in detail, through the measurement of the state-selected fragmentation pathways via the use of threshold electron/ion coincidences (TPEPICO), with appearance energies for the different

  4. Protein Content and Amino Acid Composition in Grains of Wheat-Related Species

    Institute of Scientific and Technical Information of China (English)

    JIANG Xiao-ling; TIAN Ji-chun; HAO Zhi; ZHANG Wei-dong

    2008-01-01

    The protein content and amino acid composition for 17 wheat-related species(WRS)and three common wheats(control) were determined and analyzed,and the essential amino acids(EAAs)in WRS were evaluated according to FAO/WHO amino acid recommendations.The results showed that the mean protein content for WRS was 16.67%,which was 23.21% higher than that for the control.The mean contents(g 100 g-1 protein)of most amino acids for WRS were lysine 2.74%,threonine 2.83%,phenylalanine 4.17%,isoleucine 3.42%,valine 3.90%,histidine 2.81%,glutamic acid 29.96%,proline 9.12%,glycine 3.59%,alanine 3.37%,and cysteine 1.57%,which were higher than those for the control.The contents of the other 6 amino acids for WRS were lower than those for the control.The materials(Triticum monococcum L.,Triticum carthlicum Nevski,and Triticum turgidum L.)contained relatively high concentration of the most deficient EAAs(lysine, threonine,and methionine).Comparing with FAO/WHO amino acid recommendations,the amino acid scores(AAS)of lysine(49.8%),threonine(70.7%),and sulfur-containing amino acids(74.8%)were the lowest,which were considered as the main limiting amino acids in WRS.It was observed that the materials with Triticum urartu Tum.(AA)and Aegilops speltoides Tausch.(SS)genomes had relatively high contents of protein and EAA.The contents of protein(16.91%), phenylalanine(4.78%),isoleucine(3.53%),leucine(6.16%),and valine(4.09%)for the diploid materials were higher than those for the other materials.These results will provide some information for selecting parents in breeding about nutrient quality and utilization of fine gene in wheat.

  5. Method Development for Efficient Incorporation of Unnatural Amino Acids

    KAUST Repository

    Harris, Paul D.

    2014-04-01

    The synthesis of proteins bearing unnatural amino acids has the potential to enhance and elucidate many processes in biochemistry and molecular biology. There are two primary methods for site specific unnatural amino acid incorporation, both of which use the cell’s native protein translating machinery: in vitro chemical acylation of suppressor tRNAs and the use of orthogonal amino acyl tRNA synthetases. Total chemical synthesis is theoretically possible, but current methods severely limit the maximum size of the product protein. In vivo orthogonal synthetase methods suffer from the high cost of the unnatural amino acid. In this thesis I sought to address this limitation by increasing cell density, first in shake flasks and then in a bioreactor in order to increase the yield of protein per amount of unnatural amino acid used. In a parallel project, I used the in vitro chemical acylation system to incorporate several unnatural amino acids, key among them the fluorophore BODIPYFL, with the aim of producing site specifically fluorescently labeled protein for single molecule FRET studies. I demonstrated successful incorporation of these amino acids into the trial protein GFP, although incorporation was not demonstrated in the final target, FEN1. This also served to confirm the effectiveness of a new procedure developed for chemical acylation.

  6. How amino acids and peptides shaped the RNA world.

    Science.gov (United States)

    van der Gulik, Peter T S; Speijer, Dave

    2015-01-01

    The "RNA world" hypothesis is seen as one of the main contenders for a viable theory on the origin of life. Relatively small RNAs have catalytic power, RNA is everywhere in present-day life, the ribosome is seen as a ribozyme, and rRNA and tRNA are crucial for modern protein synthesis. However, this view is incomplete at best. The modern protein-RNA ribosome most probably is not a distorted form of a "pure RNA ribosome" evolution started out with. Though the oldest center of the ribosome seems "RNA only", we cannot conclude from this that it ever functioned in an environment without amino acids and/or peptides. Very small RNAs (versatile and stable due to basepairing) and amino acids, as well as dipeptides, coevolved. Remember, it is the amino group of aminoacylated tRNA that attacks peptidyl-tRNA, destroying the bond between peptide and tRNA. This activity of the amino acid part of aminoacyl-tRNA illustrates the centrality of amino acids in life. With the rise of the "RNA world" view of early life, the pendulum seems to have swung too much towards the ribozymatic part of early biochemistry. The necessary presence and activity of amino acids and peptides is in need of highlighting. In this article, we try to bring the role of the peptide component of early life back into focus. We argue that an RNA world completely independent of amino acids never existed. PMID:25607813

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

    Science.gov (United States)

    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.

  8. Synthesis and in vivo distribution of 1-amino-3-boronocylopentanecarboxylic acids

    International Nuclear Information System (INIS)

    The success of boron neutron capture therapy (BNCT) is dependent on the selective deposition of boron-10 in tumor cells. For a number of years, we have focused our attention on the potential use of boronated cyclic amino acids as boron carriers for BNCT. The studies are an outgrowth of our earlier nuclear medicine studies using positron emission tomography that demonstrated that amino acids are preferentially taken up by tumor cells. Boronated 1-aminocyclobutanecarboxylic acid and 1-aminocyclopentanecarboxylic acid were found to be at least as tumor selective as the currently utilized BNCT agent, para-boronophenylalanine, in our tumor-bearing animal models. We wish to report the results of a study in which the diastereoisomers of 1-amino-3-boronocyclopentanecarboxylic acid were separated and their biodistribution evaluated in mice bearing EMT-6 tumors. (author)

  9. Stardust and the Molecules of Life (Why are the Amino Acids Left-Handed?)

    Energy Technology Data Exchange (ETDEWEB)

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

    2010-04-02

    A mechanism for creating and selecting amino acid chirality is identified, and subsequent chemical replication and galactic mixing that would populate the galaxy with the predominant species will be described. This involves: (1) the spin of the {sup 14}N in the amino acids, or in precursor molecules from which amino acids might be formed, coupling to the chirality of the molecules; (2) the neutrinos emitted from the supernova, together with magnetic field from the nascent neutron star or black hole from the supernova selectively destroying one orientation of the {sup 14}N, thereby selecting the chirality associated with the other {sup 14}N orientation; (3) amplification by chemical evolution, by which the molecules replicate on a relatively short timescale; and (4) galactic mixing on a longer timescale mixing the selected molecules throughout the galaxy.

  10. Covalently functionalized graphene sheets with biocompatible natural amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Mallakpour, Shadpour, E-mail: mallak@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Abdolmaleki, Amir, E-mail: abdolmaleki@cc.iut.ac.ir [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Nanotechnology and Advanced Materials Institute, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of); Borandeh, Sedigheh [Organic Polymer Chemistry Research Laboratory, Department of Chemistry, Isfahan University of Technology, Isfahan, 84156-83111, Islamic Republic of Iran (Iran, Islamic Republic of)

    2014-07-01

    Graphene sheets were covalently functionalized with aromatic–aliphatic amino acids (phenylalanine and tyrosine) and aliphatic amino acids (alanine, isoleucine, leucine, methionine and valine) by simple and green procedure. For this aim, at first natural graphite was converted into graphene oxide (GO) through strong oxidation procedure; then, based on the surface-exposed epoxy and carboxylic acid groups in GO solid, its surface modification with naturally occurring amino acids, occurred easily throughout the corresponding nucleophilic substitution and condensation reactions. Amino acid functionalized graphene demonstrates stable dispersion in water and common organic solvents. Fourier transform infrared, Raman and X-ray photoelectron spectroscopies, X-ray diffraction, field emission scanning electron microscopy and transmission electron microscopy were used to investigate the nanostructures and properties of prepared materials. Each amino acid has different considerable effects on the structure and morphology of the pure graphite, from increasing the layer spacing to layer scrolling, based on their structures, functional groups and chain length. In addition, therogravimetric analysis was used for demonstrating a successful grafting of amino acid molecules to the surface of graphene.

  11. N-13 labeled amino acids: biodistribution, metabolism and dosimetric considerations

    International Nuclear Information System (INIS)

    With the growing interest in metabolic imaging and with the increasing number of cyclotron/PET facilities, more studies are being performed in animal and humans using short-lived positron-emitting radionuclides. Amino acids labeled either with N-13 or C-11 are one group of compounds being used to study in vivo regional organ (i.e., brain and heart) or tumor metabolism. Of the studies previously reported using C-11 or N-13 labeled amino acids (methionine, alanine, valine, glutamate, glutamine and tryptophan), imaging was restricted mainly to the organ or tissue of interest with little information obtained about the whole-bode distribution of the label. Such data are important for studying interorgan transport of amino acids and for determining accurate dosimetric measurements after intravenous injection of labeled amino acids. The goals of the authors study were to compare the distribution of several N-13 L-amino acids and N-13 ammonia in tumor-bearing mice and to determine the metabolic fate of the label in vivo. The following amino acids were enzymatically labeled using N-13 ammonia: glutamine, glutamate, methionine, α-aminobutyric acid, valine and leucine. 30 references, 2 figures, 14 tables

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

    Science.gov (United States)

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

    2012-01-01

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

  13. Single amino acids in sucrose rewards modulate feeding and associative learning in the honeybee.

    Science.gov (United States)

    Simcock, Nicola K; Gray, Helen E; Wright, Geraldine A

    2014-10-01

    Obtaining the correct balance of nutrients requires that the brain integrates information about the body's nutritional state with sensory information from food to guide feeding behaviour. Learning is a mechanism that allows animals to identify cues associated with nutrients so that they can be located quickly when required. Feedback about nutritional state is essential for nutrient balancing and could influence learning. How specific this feedback is to individual nutrients has not often been examined. Here, we tested how the honeybee's nutritional state influenced the likelihood it would feed on and learn sucrose solutions containing single amino acids. Nutritional state was manipulated by pre-feeding bees with either 1M sucrose or 1M sucrose containing 100mM of isoleucine, proline, phenylalanine, or methionine 24h prior to olfactory conditioning of the proboscis extension response. We found that bees pre-fed sucrose solution consumed less of solutions containing amino acids and were also less likely to learn to associate amino acid solutions with odours. Unexpectedly, bees pre-fed solutions containing an amino acid were also less likely to learn to associate odours with sucrose the next day. Furthermore, they consumed more of and were more likely to learn when rewarded with an amino acid solution if they were pre-fed isoleucine and proline. Our data indicate that single amino acids at relatively high concentrations inhibit feeding on sucrose solutions containing them, and they can act as appetitive reinforcers during learning. Our data also suggest that select amino acids interact with mechanisms that signal nutritional sufficiency to reduce hunger. Based on these experiments, we predict that nutrient balancing for essential amino acids during learning requires integration of information about several amino acids experienced simultaneously. PMID:24819203

  14. Single amino acids in sucrose rewards modulate feeding and associative learning in the honeybee.

    Science.gov (United States)

    Simcock, Nicola K; Gray, Helen E; Wright, Geraldine A

    2014-10-01

    Obtaining the correct balance of nutrients requires that the brain integrates information about the body's nutritional state with sensory information from food to guide feeding behaviour. Learning is a mechanism that allows animals to identify cues associated with nutrients so that they can be located quickly when required. Feedback about nutritional state is essential for nutrient balancing and could influence learning. How specific this feedback is to individual nutrients has not often been examined. Here, we tested how the honeybee's nutritional state influenced the likelihood it would feed on and learn sucrose solutions containing single amino acids. Nutritional state was manipulated by pre-feeding bees with either 1M sucrose or 1M sucrose containing 100mM of isoleucine, proline, phenylalanine, or methionine 24h prior to olfactory conditioning of the proboscis extension response. We found that bees pre-fed sucrose solution consumed less of solutions containing amino acids and were also less likely to learn to associate amino acid solutions with odours. Unexpectedly, bees pre-fed solutions containing an amino acid were also less likely to learn to associate odours with sucrose the next day. Furthermore, they consumed more of and were more likely to learn when rewarded with an amino acid solution if they were pre-fed isoleucine and proline. Our data indicate that single amino acids at relatively high concentrations inhibit feeding on sucrose solutions containing them, and they can act as appetitive reinforcers during learning. Our data also suggest that select amino acids interact with mechanisms that signal nutritional sufficiency to reduce hunger. Based on these experiments, we predict that nutrient balancing for essential amino acids during learning requires integration of information about several amino acids experienced simultaneously.

  15. Profile of Fatty Acids, Amino Acids, Carotenoid Total, and α-Tocopherol from Flying Fish Eggs

    Directory of Open Access Journals (Sweden)

    Aulia Azka

    2015-12-01

    Full Text Available Flying fish are found in waters of eastern Indonesia, which until now is still limited information about nutritional content. The purpose of this research was determine the composition of fatty acids, amino acids, total carotenoids, α-tocopherol flying fish eggs (Hyrundicthys sp.. The composition of fatty acid was measured by gas chromatography (GC, while amino acids, total carotenoids, α-tocopherol was measured by High performanced Liquid Chromatography (HPLC. Egg contained 22 fatty acids such as saturated fatty acid 29.71%, monounsaturated fatty acid 7.86%, and polysaturated fatty acid 13.64%. The result showed that eggs flying fish contained 17 amino acids, such as essential amino acid 14.96% and non-essential amino acids 20.27%. Eggs contained a total carotenoid of 245.37 ppm. α-tocopherol content of flying fish eggs by 1.06 ppm.

  16. Sugar amino acids and related molecules: Some recent developments

    Indian Academy of Sciences (India)

    Tushar Kanti Chakraborty; Pothukanuri Srinivasu; Subhasish Tapadar; Bajjuri Krishna Mohan

    2004-06-01

    To meet the growing demands for the development of new molecular entities for discovering new drugs and materials, organic chemists have started working on many new concepts that can help to assimilate knowledge-based structural diversities more efficiently than ever before. Emulating the basic principles followed by Nature to build its vast repertoire of biomolecules, organic chemists are developing many novel multifunctional building blocks and using them to create `nature-like’ and yet unnatural organic molecules. Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature’s molecular arsenal. In recent years, sugar amino acids have been used extensively in the area of peptidomimetic studies. Advances made in the area of combinatorial chemistry can provide the necessary technological support for rapid compilations of sugar amino acidbased libraries exploiting the diversities of their carbohydrate frameworks and well-developed solidphase peptide synthesis methods. This perspective article chronicles some of the recent applications of various sugar amino acids, furan amino acids, pyrrole amino acids etc. and many other related building blocks in wide-ranging peptidomimetic studies.

  17. Disturbed amino acid metabolism in HIV: association with neuropsychiatric symptoms

    Directory of Open Access Journals (Sweden)

    Johanna M Gostner

    2015-07-01

    Full Text Available Blood levels of the amino acid phenylalanine, as well as of the tryptophan breakdown product kynurenine, are found to be elevated in human immunodeficiency virus type 1 (HIV-1-infected patients. Both essential amino acids, tryptophan and phenylalanine are important precursor molecules for neurotransmitter biosynthesis. Thus, dysregulated amino acid metabolism may be related to disease-associated neuropsychiatric symptoms such as development of depression, fatigue, and cognitive impairment.Increased phenylalanine/tyrosine and kynurenine/tryptophan ratios are associated with immune activation in patients with HIV-1 infection and decrease upon effective antiretroviral therapy. Recent large-scale metabolic studies have confirmed the crucial involvement of tryptophan and phenylalanine metabolism in HIV-associated disease. Herein, we summarize the current status of the role of tryptophan and phenylalanine metabolism in HIV disease and discuss how inflammatory stress-associated dysregulation of amino acid metabolism may be part of the pathophysiology of common HIV-associated neuropsychiatric conditions.

  18. Displacement of carbon-14 labelled amino acids from leaves

    International Nuclear Information System (INIS)

    The displacement of amino acids from nature leaves was investigated. The amino acids (Ala, Asn, Asp, Glu, Gln, Val, Leu, Lys, Ser, Pro) were applied on the leaves in L-form, uniformly labelled with 14C, and the type and direction of displacement have been observed. Most of the studies have been carried out on bush beans aged 3 to 4 weeks. The experiments were carried out in climatic chambers; in one case, barley plants just reaching maturity were used. In order to find out whether the applied amino acids were also displaced in their original form, freeze-dried plants were extracted and the 14C activity of the various fraction was determined. The radioactivity of some free amino acids was determined after two-dimensional separation by thin film chromatography. (orig./HK)

  19. Detecting coevolving amino acid sites using Bayesian mutational mapping

    DEFF Research Database (Denmark)

    Dimmic, Matthew W.; Hubisz, Melissa J.; Bustamente, Carlos D.;

    2005-01-01

    Motivation: The evolution of protein sequences is constrained by complex interactions between amino acid residues. Because harmful substitutions may be compensated for by other substitutions at neighboring sites, residues can coevolve. We describe a Bayesian phylogenetic approach to the detection...

  20. Comparing Amino Acid Abundances and Distributions Across Carbonaceous Chondrite Groups

    Science.gov (United States)

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

    2012-01-01

    Meteorites are grouped according to bulk properties such as chemical composition and mineralogy. These parameters can vary significantly among the different carbonaceous chondrite groups (CI, CM, CO, CR, CH, CB, CV and CK). We have determined the amino acid abundances of more than 30 primary amino acids in meteorites from each of the eight groups, revealing several interesting trends. There are noticeable differences in the structural diversity and overall abundances of amino acids between meteorites from the different chondrite groups. Because meteorites may have been an important source of amino acids to the prebiotic Earth and these organic compounds are essential for life as we know it, the observed variations of these molecules may have been important for the origins of life.

  1. Reconstructing a Flavodoxin Oxidoreductase with Early Amino Acids

    Directory of Open Access Journals (Sweden)

    Hong-Yu Zhang

    2013-06-01

    Full Text Available Primitive proteins are proposed to have utilized organic cofactors more frequently than transition metals in redox reactions. Thus, an experimental validation on whether a protein constituted solely by early amino acids and an organic cofactor can perform electron transfer activity is an urgent challenge. In this paper, by substituting “late amino acids (C, F, M, T, W, and Y” with “early amino acids (A, L, and V” in a flavodoxin, we constructed a flavodoxin mutant and evaluated its characteristic properties. The major results showed that: (1 The flavodoxin mutant has structural characteristics similar to wild-type protein; (2 Although the semiquinone and hydroquinone flavodoxin mutants possess lower stability than the corresponding form of wild-type flavodoxin, the redox potential of double electron reduction Em,7 (fld reached −360 mV, indicating that the flavodoxin mutant constituted solely by early amino acids can exert effective electron transfer activity.

  2. Detection of COL III in Parchment by Amino Acid Analysis

    DEFF Research Database (Denmark)

    Vestergaard Poulsen Sommer, Dorte; Larsen, René

    2016-01-01

    Cultural heritage parchments made from the reticular dermis of animals have been subject to studies of deterioration and conservation by amino acid analysis. The reticular dermis contains a varying mixture of collagen I and III (COL I and III). When dealing with the results of the amino acid...... analyses, till now the COL III content has not been taken into account. Based on the available amino acid sequences we present a method for determining the amount of COL III in the reticular dermis of new and historical parchments calculated from the ratio of Ile/Val. We find COL III contents between 7...... and 32 % in new parchments and between 0.2 and 40 % in the historical parchments. This is consistent with results in the literature. The varying content of COL III has a significant influence on the uncertainty of the amino acid analysis. Although we have not found a simple correlation between the COL...

  3. Microbes Promote Amino Acid Harvest to Rescue Undernutrition in Drosophila

    Directory of Open Access Journals (Sweden)

    Ryuichi Yamada

    2015-02-01

    Full Text Available Microbes play an important role in the pathogenesis of nutritional disorders such as protein-specific malnutrition. However, the precise contribution of microbes to host energy balance during undernutrition is unclear. Here, we show that Issatchenkia orientalis, a fungal microbe isolated from field-caught Drosophila melanogaster, promotes amino acid harvest to rescue the lifespan of undernourished flies. Using radioisotope-labeled dietary components (amino acids, nucleotides, and sucrose to quantify nutrient transfer from food to microbe to fly, we demonstrate that I. orientalis extracts amino acids directly from nutrient-poor diets and increases protein flux to the fly. This microbial association restores body mass, protein, glycerol, and ATP levels and phenocopies the metabolic profile of adequately fed flies. Our study uncovers amino acid harvest as a fundamental mechanism linking microbial and host metabolism, and highlights Drosophila as a platform for quantitative studies of host-microbe relationships.

  4. Comparison of amino acids interaction with gold nanoparticle.

    Science.gov (United States)

    Ramezani, Fatemeh; Amanlou, Massoud; Rafii-Tabar, Hashem

    2014-04-01

    The study of nanomaterial/biomolecule interface is an important emerging field in bionanoscience, and additionally in many biological processes such as hard-tissue growth and cell-surface adhesion. To have a deeper understanding of the amino acids/gold nanoparticle assemblies, the adsorption of these amino acids on the gold nanoparticles (GNPs) has been investigated via molecular dynamics simulation. In these simulations, all the constituent atoms of the nanoparticles were considered to be dynamic. The geometries of amino acids, when adsorbed on the nanoparticle, were studied and their flexibilities were compared with one another. The interaction of each of 20 amino acids was considered with 3 and 8 nm gold GNPs.

  5. Inhibitors of amino acids biosynthesis as antifungal agents.

    Science.gov (United States)

    Jastrzębowska, Kamila; Gabriel, Iwona

    2015-02-01

    Fungal microorganisms, including the human pathogenic yeast and filamentous fungi, are able to synthesize all proteinogenic amino acids, including nine that are essential for humans. A number of enzymes catalyzing particular steps of human-essential amino acid biosynthesis are fungi specific. Numerous studies have shown that auxotrophic mutants of human pathogenic fungi impaired in biosynthesis of particular amino acids exhibit growth defect or at least reduced virulence under in vivo conditions. Several chemical compounds inhibiting activity of one of these enzymes exhibit good antifungal in vitro activity in minimal growth media, which is not always confirmed under in vivo conditions. This article provides a comprehensive overview of the present knowledge on pathways of amino acids biosynthesis in fungi, with a special emphasis put on enzymes catalyzing particular steps of these pathways as potential targets for antifungal chemotherapy.

  6. Azide- and alkyne-derivatised α-amino acids

    DEFF Research Database (Denmark)

    Johansson, Karl Henrik; Pedersen, D.S.

    2012-01-01

    for their synthesis. In this review we have compiled available methods for synthesising optically active azide- and alkyne-derivatised α-amino acids that can be prepared from readily available α-amino acids. We highlight a number of commonly overlooked problems associated with existing methods and direct attention......With the emergence of the copper-catalysed Huisgen cycloaddition the use of azide- and alkyne-derivatised α-amino acids has found widespread use within most chemistry disciplines. Despite a growing interest in these building blocks researchers are struggling to identify the best way...... to unexplored possibilities. Azide- and alkyne-derivatised α-amino acids are finding widespread use within most chemistry disciplines. However, it is far from clear what the best way for the synthesis of these useful building blocks is. Herein we show the available methods for synthesis of optically active...

  7. D-amino acid-induced expression of D-amino acid oxidase in the yeast Schizosaccharomyces pombe.

    Science.gov (United States)

    Takahashi, Shouji; Okada, Hirotsune; Abe, Katsumasa; Kera, Yoshio

    2012-12-01

    We investigated D-amino acid oxidase (DAO) induction in the popular model yeast Schizosaccharomyces pombe. The product of the putative DAO gene of the yeast expressed in E. coli displayed oxidase activity to neutral and basic D-amino acids, but not to an L-amino acid or acidic D-amino acids, showing that the putative DAO gene encodes catalytically active DAO. DAO activity was weakly detected in yeast cells grown on a culture medium without D-amino acid, and was approximately doubled by adding D-alanine. The elimination of ammonium chloride from culture medium induced activity by up to eight-fold. L-Alanine also induced the activity, but only by about half of that induced by D-alanine. The induction by D-alanine reached a maximum level at 2 h cultivation; it remained roughly constant until cell growth reached a stationary phase. The best inducer was D-alanine, followed by D-proline and then D-serine. Not effective were N-carbamoyl-D,L-alanine (a better inducer of DAO than D-alanine in the yeast Trigonopsis variabilis), and both basic and acidic D-amino acids. These results showed that S. pombe DAO could be a suitable model for analyzing the regulation of DAO expression in eukaryotic organisms. PMID:22986818

  8. Factors influencing the rate of non-enzymatic activation of carboxylic and amino acids by ATP

    Science.gov (United States)

    Mullins, D. W., Jr.; Lacey, J. C., Jr.

    1981-01-01

    The nonenzymatic formation of adenylate anhydrides of carboxylic and amino acids is discussed as a necessary step in the origin of the genetic code and protein biosynthesis. Results of studies are presented which have shown the rate of activation to depend on the pKa of the carboxyl group, the pH of the medium, temperature, the divalent metal ion catalyst, salt concentration, and the nature of the amino acid. In particular, it was found that of the various amino acids investigated, phenylalanine had the greatest affinity for the adenine derivatives adenosine and ATP. Results thus indicate that selective affinities between amino acids and nucleotides were important during prebiotic chemical evolution, and may have played a major role in the origin of protein synthesis and genetic coding.

  9. Facile synthesis of α-hydroxy carboxylic acids from the corresponding α-amino acids

    DEFF Research Database (Denmark)

    Stuhr-Hansen, Nicolai; Padrah, Shahrokh; Strømgaard, Kristian

    2014-01-01

    An effective and improved procedure is developed for the synthesis of α-hydroxy carboxylic acids by treatment of the corresponding protonated α-amino acid with tert-butyl nitrite in 1,4-dioxane-water. The amino moiety must be protonated and located α to a carboxylic acid function in order...... to undergo initial diazotization and successive hydroxylation, since neither β-amino acids nor acid derivatives such as esters and amides undergo hydroxylations. The method is successfully applied for the synthesis of 18 proteinogenic amino acids. © 2014 Elsevier Ltd. All rights reserved....

  10. Amino Acid Interaction Network Prediction Using Multi-Objective Optimization

    Directory of Open Access Journals (Sweden)

    Md. Shiplu Hawlader

    2014-01-01

    Full Text Available Protein can be represented by amino acid interaction network. This network is a graph whose vertices are the proteins amino acids and whose edges are the interactions between them. This interaction network is the first step of proteins three-dimensional structure prediction. In this paper we present a multi-objective evolutionary algorithm for interaction prediction and ant colony probabilistic optimization algorithm is used to confirm the interaction.

  11. Review: Taurine: A “very essential” amino acid

    OpenAIRE

    Ripps, Harris; Shen, Wen

    2012-01-01

    Taurine is an organic osmolyte involved in cell volume regulation, and provides a substrate for the formation of bile salts. It plays a role in the modulation of intracellular free calcium concentration, and although it is one of the few amino acids not incorporated into proteins, taurine is one of the most abundant amino acids in the brain, retina, muscle tissue, and organs throughout the body. Taurine serves a wide variety of functions in the central nervous system, from development to cyto...

  12. FLU, an amino acid substitution model for influenza proteins

    OpenAIRE

    Gascuel Olivier; Le Quang; Dang Cuong; Le Vinh

    2010-01-01

    Abstract Background The amino acid substitution model is the core component of many protein analysis systems such as sequence similarity search, sequence alignment, and phylogenetic inference. Although several general amino acid substitution models have been estimated from large and diverse protein databases, they remain inappropriate for analyzing specific species, e.g., viruses. Emerging epidemics of influenza viruses raise the need for comprehensive studies of these dangerous viruses. We p...

  13. Importance of amino acids on vasopressin-stimulated water flow.

    OpenAIRE

    Carvounis, C P; Carvounis, G; Wilk, B J

    1985-01-01

    The presence of several naturally occurring amino acids in the serosal bath of toad urinary bladder significantly alters the hydrosmotic response of this tissue to vasopressin. We found that histidine, glutamate, and lysine increase vasopressin-stimulated water flow by 75%, 60%, and 43%, respectively. In contrast, alanine did not alter vasopressin-stimulated water flow, whereas glutamine decreased it by 25%. The effect of each amino acid represents intracellular events because their effects o...

  14. Stereoselective synthesis of unsaturated α-amino acids.

    Science.gov (United States)

    Fanelli, Roberto; Jeanne-Julien, Louis; René, Adeline; Martinez, Jean; Cavelier, Florine

    2015-06-01

    Stereoselective synthesis of unsaturated α-amino acids was performed by asymmetric alkylation. Two methods were investigated and their enantiomeric excess measured and compared. The first route consisted of an enantioselective approach induced by the Corey-Lygo catalyst under chiral phase transfer conditions while the second one involved the hydroxypinanone chiral auxiliary, both implicating Schiff bases as substrate. In all cases, the use of a prochiral Schiff base gave higher enantiomeric excess and yield in the final desired amino acid.

  15. Co2 chemosorption by functionalized amino acid derivatives

    DEFF Research Database (Denmark)

    2015-01-01

    The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid.......The absorption and desorption behaviour of carbon dioxide (CO2) using a composition comprising an ionic compound comprising a cation [A+] and an anion [B-] is described, wherein the anion [B-] is a mono-amine functionalized amino acid....

  16. Mutational library analysis of selected amino acids in the receptor binding domain of envelope of Akv murine leukemia virus by conditionally replication competent bicistronic vectors

    DEFF Research Database (Denmark)

    Bahrami, Shervin; Pedersen, Finn Skou; Duch, Mogens R.;

    2003-01-01

    ) and the neomycin phosphotransferase II (Neo) selection marker from the same transcript. Envelope expression was achieved by inserting an internal ribosome entry site (IRES) between the neo and the env genes. We found the structure of the linker between the IRES element and env to be critical for sufficient...

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

    Science.gov (United States)

    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 ( ∆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, 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.

  18. Extraterrestrial Amino Acids in Ureilites Including Almahata Sitta

    Science.gov (United States)

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

    2011-01-01

    Ureilites are a class of meteorites that lack chondrules (achondrites) but have relatively high carbon abundances, averaging approx.3 wt %. Using highly sensitive liquid chromatography coupled with UV fluorescence and time-of-flight mass spectrometry (LC-FD/ToF-MS), it was recently determined that there are amino acids in. fragment 94 of the Almahata Sitta ureilite[l]. Based on the presence of amino acids that are rare in the Earth's biosphere, as well as the near-racemic enantiomeric ratios of marry of the more common amino acids, it was concluded that most of the detected amino acids were indigenous to the meteorite. Although the composition of the Almahata Sitta ureilite appears to be unlike other recovered ureilites, the discovery of amino acids in this meteorite raises the question of whether other ureilites rnav also contain amino acids. Herein we present the results of LC-FDlTo.F-MS analyses of: a sand sample from the Almahata Sitta strewn held, Almahata Sitta fragments 425 (an ordinary H5 chondrite) and 427 (ureilite), as well as an Antarctic ureilite (Allan lulls, ALHA 77257).

  19. Alterations in Plasma Amino Acid Levels in Chronic Pancreatitis

    Directory of Open Access Journals (Sweden)

    Banavara Narasimhamurthy Girish

    2011-01-01

    Full Text Available Context Dietary proteins and amino acids can modulate pancreatic function. Objective Our aim was to estimate the levels of plasma amino acids in chronic pancreatitis patients and study their relationship with disease characteristics as well as exocrine and endocrine insufficiency. Patients One hundred and seventy-five consecutive adult patients with chronic pancreatitis: 84 patients with alcoholic chronic pancreatitis and 91 patients with tropical chronic pancreatitis. One hundred and thirteen healthy controls were also studied. Design Prospective study. Main outcome measures Disease characteristics and imaging features were recorded. Plasma-free amino acid levels were estimated using reverse-phase high-performance liquid chromatography. Polyclonal antibody ELISA was used to assess pancreatic fecal elastase-1. Results The majority of the plasma free amino acid levels decreased in chronic pancreatitis patients whereas glutamate, glycine, proline and lysine were elevated as compared to the controls. Multivariate logistic regression analysis revealed that the decrease in branched chain amino acid concentration was significantly associated with the presence of diabetes and low fecal elastase-1. In addition, a significant positive correlation was observed between branched chain amino acids and pancreatic elastase-1 (rs=0.724, P

  20. The preferences of orientations between the Pairs of amino acids

    Institute of Scientific and Technical Information of China (English)

    Chen Ying; Wang Jun; Wang Wei

    2007-01-01

    In this work,we make an investigation on the preferences of orientations between amino acids using the orientation defined based on the local geometry of the amino acids concerned.It is found that there are common preferences of orientations (70°,30°,140°) and (110°,340°,100°) for various pairs of amino acids.Different side chains may strengthen or weaken the common preferences,which is related to the effect of packing.Some amino acids having specific local flexibility may possess some preferences of orientations besides the common ones,such as (10°,280°,210°) .Another analysis on the pairs of the amino acids with different secondary-structure preferences shows that the directional interaction may affect the distribution of orientation more effectively than the packing or local flexibility.All these results provide us some insight of the organization of amino acids in protein,and their relation with some related interactions.

  1. 77 FR 65537 - Requirements for Patent Applications Containing Nucleotide Sequence and/or Amino Acid Sequence...

    Science.gov (United States)

    2012-10-29

    ... Amino Acid Sequence Disclosures ACTION: Proposed collection; comment request. SUMMARY: The United States....'' SUPPLEMENTARY INFORMATION: I. Abstract Patent applications that contain nucleotide and/or amino acid...

  2. Abiotic Racemization Kinetics of Amino Acids in Marine Sediments

    OpenAIRE

    Steen, Andrew D.; Bo Barker Jørgensen; Bente Aa Lomstein

    2013-01-01

    The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth be...

  3. Heat-Bath Cooling of Spins in Amino Acids

    CERN Document Server

    Elias, Yuval; Mor, Tal; Weinstein, Yossi

    2011-01-01

    Heat-bath cooling is a component of practicable algorithmic cooling of spins, an approach which might be useful for in vivo 13C spectroscopy, in particular for prolonged metabolic processes where substrates that are hyperpolarized ex-vivo are not effective. We applied heat-bath cooling to 1,2-13C2-amino acids, using the \\alpha\\ protons to shift entropy from selected carbons to the environment. For glutamate and glycine, the polarizations of both labeled carbons were enhanced, and in other experiments the total entropy of each spin system was shown to decrease. The effect of adding Magnevist, a gadolinium contrast agent, on heat-bath cooling of glutamate was investigated.

  4. Unusually Large Young's Moduli of Amino Acid Molecular Crystals.

    Science.gov (United States)

    Azuri, Ido; Meirzadeh, Elena; Ehre, David; Cohen, Sidney R; Rappe, Andrew M; Lahav, Meir; Lubomirsky, Igor; Kronik, Leeor

    2015-11-01

    Young's moduli of selected amino acid molecular crystals were studied both experimentally and computationally using nanoindentation and dispersion-corrected density functional theory. The Young modulus is found to be strongly facet-dependent, with some facets exhibiting exceptionally high values (as large as 44 GPa). The magnitude of Young's modulus is strongly correlated with the relative orientation between the underlying hydrogen-bonding network and the measured facet. Furthermore, we show computationally that the Young modulus can be as large as 70-90 GPa if facets perpendicular to the primary direction of the hydrogen-bonding network can be stabilized. This value is remarkably high for a molecular solid and suggests the design of hydrogen-bond networks as a route for rational design of ultra-stiff molecular solids.

  5. Evolutionary adaptation of the amino acid and codon usage of the mosquito sodium channel following insecticide selection in the field mosquitoes.

    Directory of Open Access Journals (Sweden)

    Qiang Xu

    Full Text Available Target site insensitivity resulting from point mutations within the voltage-gated sodium channel of the insect nervous system is known to be of primary importance in the development of resistance to pyrethroid insecticides. This study shifts current research paradigms by conducting, for the first time, a global analysis of all the naturally occurring mutations, both nonsynonymous and synonymous mutations, as well as mutation combinations in the entire mosquito sodium channel of Culex quinquefasciatus and analyzing their evolutionary and heritable feature and roles in insecticide resistance. Through a systematic analysis of comparing nucleotide polymorphisms in the entire sodium channel cDNAs of individuals between susceptible and resistant mosquito strains, between field parental mosquitoes and their permethrin selected offspring, and among different mosquito groups categorized by their levels of tolerance to specific permethrin concentrations within and among the mosquito strains of the field parental strains and their permethrin selected offspring, 3 nonsynonymous (A(109S, L(982F, and W(1573R and 6 synonymous (L(852, G(891, A(1241, D(1245, P(1249, and G(1733 mutations were identified. The co-existence of all 9 mutations, both nonsynonymous and synonymous, and their homozygousity were found to be important factors for high levels of resistance. Our study, for the first time, provide a strong case demonstrating the co-existence of both nonsynonymous and synonymous mutations in the sodium channel of resistant mosquitoes in response to insecticide resistance and the inheritance of these mutations in the offspring of field mosquito strains following insecticide selection.

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

    Science.gov (United States)

    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, 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.

  7. Affinity-Based Screening of Tetravalent Peptides Identifies Subtype-Selective Neutralizers of Shiga Toxin 2d, a Highly Virulent Subtype, by Targeting a Unique Amino Acid Involved in Its Receptor Recognition.

    Science.gov (United States)

    Mitsui, Takaaki; Watanabe-Takahashi, Miho; Shimizu, Eiko; Zhang, Baihao; Funamoto, Satoru; Yamasaki, Shinji; Nishikawa, Kiyotaka

    2016-09-01

    Shiga toxin (Stx), a major virulence factor of enterohemorrhagic Escherichia coli (EHEC), can be classified into two subgroups, Stx1 and Stx2, each consisting of various closely related subtypes. Stx2 subtypes Stx2a and Stx2d are highly virulent and linked with serious human disorders, such as acute encephalopathy and hemolytic-uremic syndrome. Through affinity-based screening of a tetravalent peptide library, we previously developed peptide neutralizers of Stx2a in which the structure was optimized to bind to the B-subunit pentamer. In this study, we identified Stx2d-selective neutralizers by targeting Asn16 of the B subunit, an amino acid unique to Stx2d that plays an essential role in receptor binding. We synthesized a series of tetravalent peptides on a cellulose membrane in which the core structure was exactly the same as that of peptides in the tetravalent library. A total of nine candidate motifs were selected to synthesize tetravalent forms of the peptides by screening two series of the tetravalent peptides. Five of the tetravalent peptides effectively inhibited the cytotoxicity of Stx2a and Stx2d, and notably, two of the peptides selectively inhibited Stx2d. These two tetravalent peptides bound to the Stx2d B subunit with high affinity dependent on Asn16. The mechanism of binding to the Stx2d B subunit differed from that of binding to Stx2a in that the peptides covered a relatively wide region of the receptor-binding surface. Thus, this highly optimized screening technique enables the development of subtype-selective neutralizers, which may lead to more sophisticated treatments of infections by Stx-producing EHEC. PMID:27382021

  8. Amino acid profile during exercise and training in Standardbreds.

    Science.gov (United States)

    Westermann, C M; Dorland, L; Wijnberg, I D; de Sain-van der Velden, M G M; van Breda, E; Barneveld, A; de Graaf-Roelfsema, E; Keizer, H A; van der Kolk, J H

    2011-08-01

    The objective of this study is to assess the influence of acute exercise, training and intensified training on the plasma amino acid profile. In a 32-week longitudinal study using 10 Standardbred horses, training was divided into four phases, including a phase of intensified training for five horses. At the end of each phase, a standardized exercise test, SET, was performed. Plasma amino acid concentrations before and after each SET were measured. Training significantly reduced mean plasma aspartic acid concentration, whereas exercise significantly increased the plasma concentrations of alanine, taurine, methionine, leucine, tyrosine and phenylalanine and reduced the plasma concentrations of glycine, ornithine, glutamine, citrulline and serine. Normally and intensified trained horses differed not significantly. It is concluded that amino acids should not be regarded as limiting training performance in Standardbreds except for aspartic acid which is the most likely candidate for supplementation. PMID:20863542

  9. Promiscuous Seven Transmembrane Receptors Sensing L-α-amino Acids

    DEFF Research Database (Denmark)

    Smajilovic, Sanela; Wellendorph, Petrine; Bräuner-Osborne, Hans

    2014-01-01

    A number of nutrient sensing seven trans-membrane (7TM) receptors have been identified and characterized over the past few years. While the sensing mechanisms to carbohydrates and free fatty acids are well understood, the molecular basis of amino acid sensing has recently come to the limelight. T....... The present review describes the current status of promiscuous L-α-amino acid sensors, the calcium sensing receptor (CaSR), the GPRC6A receptor, the T1R1/T1R3 receptor and also their molecular pharmacology, expression pattern and physiological significance.......A number of nutrient sensing seven trans-membrane (7TM) receptors have been identified and characterized over the past few years. While the sensing mechanisms to carbohydrates and free fatty acids are well understood, the molecular basis of amino acid sensing has recently come to the limelight...

  10. Abiotic racemization kinetics of amino acids in marine sediments.

    Science.gov (United States)

    Steen, Andrew D; Jørgensen, Bo Barker; Lomstein, Bente Aa

    2013-01-01

    The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth below seafloor. Extrapolation to a typical cold deep sea sediment temperature of 3°C suggests racemization rate constants of 0.50×10(-5)-11×10(-5) yr(-1). These results can be used in conjunction with measurements of sediment age to predict the ratio of d:l amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial populations.

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

    OpenAIRE

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

    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 chromatog...

  12. Density, viscosity, and N2O solubility of aqueous amino acid salt and amine amino acid salt solutions

    International Nuclear Information System (INIS)

    Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N2O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N2O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N2O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N2O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N2O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N2O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

  13. The interaction of amino acids, peptides, and proteins with DNA.

    Science.gov (United States)

    Solovyev, Andrey Y; Tarnovskaya, Svetlana I; Chernova, Irina A; Shataeva, Larisa K; Skorik, Yury A

    2015-01-01

    Amino acids that carry charges on their side groups can bind to double stranded DNA (dsDNA) and change the strength of the double helix. Measurement of the DNA melting temperature (Tm) confirmed that acidic amino acids (Glu, Asp) weaken the H-bonds between DNA strands, whereas basic amino acids (Arg, Lys) strengthen the interaction between the strands. A rank correlation exists between the amino acid isoelectric points and the observed changes in Tm. A similar dependence of the hyperchromic effect on the isoelectric point of a protein (pepsin, insulin, cortexin, and protamine) was observed for DNA-protein complexes at room temperature. Short peptides (KE, AEDG, and KEDP) containing a mixture of acidic and basic amino acid residues also affect Tm and the stability of the double helix. A model for binding Glu and Lys to dsDNA was explored by a docking simulation. The model shows that Glu, in an untwisted shape, binds to dsDNA in its major groove and disrupts three H-bonds between the strands, thereby destabilizing the double helix. Lys, in an untwisted shape, binds to the external side of the dsDNA and forms two bonds with O atoms of neighboring phosphodiester groups, thereby strengthening the DNA helix.

  14. Raman spectra of amino acids and their aqueous solutions

    Science.gov (United States)

    Zhu, Guangyong; Zhu, Xian; Fan, Qi; Wan, Xueliang

    2011-03-01

    Amino acids are the basic "building blocks" that combine to form proteins and play an important physiological role in all life-forms. Amino acids can be used as models for the examination of the importance of intermolecular bonding in life processes. Raman spectra serve to obtain information regarding molecular conformation, giving valuable insights into the topology of more complex molecules (peptides and proteins). In this paper, amino acids and their aqueous solution have been studied by Raman spectroscopy. Comparisons of certain values for these frequencies in amino acids and their aqueous solutions are given. Spectra of solids when compared to those of the solute in solution are invariably much more complex and almost always sharper. We present a collection of Raman spectra of 18 kinds of amino acids ( L-alanine, L-arginine, L-aspartic acid, cystine, L-glutamic acid, L-glycine, L-histidine, L-isoluecine, L-leucine, L-lysine, L-phenylalanine, L-methionone, L-proline, L-serine, L-threonine, L-tryptophan, L-tyrosine, L-valine) and their aqueous solutions that can serve as references for the interpretation of Raman spectra of proteins and biological materials.

  15. Energetics of Amino Acid Synthesis in Alkaline Hydrothermal Environments

    Science.gov (United States)

    Kitadai, Norio

    2015-12-01

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

  16. Aminoácidos para frangos de corte Amino acids for broilers

    Directory of Open Access Journals (Sweden)

    Adhemar Rodrigues de Oliveira Neto

    2009-07-01

    Full Text Available A utilização de aminoácidos digestíveis e da proteína ideal auxiliou a reduzir as excreções de nitrogênio para o ambiente e o custo da ração formulada, sem afetar negativamente o desempenho dos frangos de corte. Entretanto, apesar de ser reconhecido como a melhor ferramenta atual para se formular rações, alguns fatores ainda devem ser elucidados para a melhor utilização do conceito de proteína ideal e para se alcançar o melhor desempenho das aves. Estes fatores são: o conhecimento das exigências dos aminoácidos não essenciais; a utilização do bom senso nas metodologias empregadas para se definir as exigências de aminoácidos; o conhecimento das exigências dos aminoácidos e a definição da proteína ideal para aves criadas em diferentes condições ambientais e sanitárias.Utilization of digestible amino acid and ideal protein concepts helped to reduce environmental nitrogen excretion and the feed formulation cost without to cause bad performance in broilers. Nevertheless, besides to be recognized that is the best tool at the moment, some factors still should be elucidate to obtain the best utilization of the ideal protein and to reach the best broiler performance. These factors are: knowing about non essential amino acids requirement; utilization good sense to use methodologies to reach amino acid requirement; knowing about amino acid requirement and ideal protein definition for broiler raised in environment and health different.

  17. Synthesis and Biological Activity of Novel Amino Acid-(N'-Benzoyl Hydrazide and Amino Acid-(N'-Nicotinoyl Hydrazide Derivatives

    Directory of Open Access Journals (Sweden)

    Sherine N. Khattab

    2005-09-01

    Full Text Available The coupling reaction of benzoic acid and nicotinic acid hydrazides with N- protected L-amino acids including valine, leucine, phenylalanine, glutamic acid and tyrosine is reported. The target compounds, N-Boc-amino acid-(N`-benzoyl- and N- Boc-amino acid-(N`-nicotinoyl hydrazides 5a-5e and 6a-6e were prepared in very high yields and purity using N-[(dimethylamino-1H-1,2,3-triazolo[4,5-b]pyridin-1-yl- methylene]-N-methyl-methanaminium hexafluorophosphate N-oxide (HATU as coupling reagent. The antimicrobial activity of the Cu and Cd complexes of the designed compounds was tested. The products were deprotected affording the corresponding amino acid-(N`-benzoyl hydrazide hydrochloride salts (7a-7e and amino acid-(N`- nicotinoyl hydrazide hydrochloride salts (8a-8e. These compounds and their Cu and Cd complexes were also tested for their antimicrobial activity. Several compounds showed comparable activity to that of ampicillin against S. aureus and E. coli.

  18. A multi-enzymatic cascade reaction for the stereoselective production of γ-oxyfunctionalyzed amino acids

    Directory of Open Access Journals (Sweden)

    Junichi eEnoki

    2016-04-01

    Full Text Available A stereoselective three-enzyme cascade for synthesis of diasteromerically pure γ-oxyfunctionalized α-amino acids was developed. By coupling a dynamic kinetic resolution using an N-acylamino acid racemase and an L-selective aminoacylase from Geobacillus thermoglucosidasius with a stereoselective isoleucine dioxygenase from Bacillus thuringiensis, diastereomerically pure oxidized amino acids were produced from racemic N-acetylamino acids. The three enzymes differ in their optimal temperature and pH-spectra. Their different metal cofactor dependencies lead to inhibitory effects. Under optimized conditions, racemic N-acetylmethionine was quantitatively converted into L-methionine-(S-sulfoxide with 97% conversion and 95% de. The combination of these three different biocatalysts allows the direct synthesis of diastereopure oxyfunctionalized amino acids from inexpensive racemic starting material.

  19. Amino acid salt solutions as solvents in CO2 capture from flue gas

    DEFF Research Database (Denmark)

    Lerche, Benedicte Mai; Thomsen, Kaj; Stenby, Erling Halfdan

    solutions is their ability to form solid precipitates upon the absorption of CO2. The occurrence of crystallization offers the possibility of increasing the CO2 loading capacity of the solvent. However, precipitation can also have negative effect on the CO2 capture process. The chemical nature of the solid...... loading capacity of aqueous solutions of the potassium salts of selected amino-acids (glycine, taurine, lysine proline, and glutamic acid) were examined, and the relation between the initial amino acid salt concentration and precipitation ability of each solution were determined. Experiments were...... of glycine, taurine, and lysine, while in the case of proline, and glutamic acid, the precipitate was found to be bicarbonate. These results give an important contribution to further understanding the potential of amino acid salt solutions in CO2 capture from flue gas....

  20. Amino acids in dew - origin and seasonal variation

    Science.gov (United States)

    Scheller, Edwin

    At two sites in the Armenhof district, 10 km east of Fulda, Germany, dew samples were collected from June 1996 to June 1997 and investigated for free and protein-bound amino acids. On account of the high pollen content, at the beginning of June 1996 and in May 1997 total amino acid concentrations were 53-390 μmol l -1, in one sample 922 μmol l -1. At other times the concentration in dew was 8-164 μmol l -1. On 4 and 5 June 1996 the diluted free amino acid fraction (DFAA) of the total hydrolysed amino acids (THAA) at both sites amounted to 35-44% and was predominantly arginine, proline and glutamine/glutamate. Likewise on 11 March 1997 the fraction of DFAA was found to be 39.5% with extremely high arginine and proline fractions. At other times the DFAA-fraction was in the range 14-26%. From July 1996 to June 1997 the amino acid concentrations in the vapours rising from a meadow were also measured and it ranged from 8 to 51 μmol l -1. From July to October 1996 the amino acid composition in the hydrolysates of dew samples and meadow vapours collected overnight were almost identical. The DFAA fraction in the condensation water collected overnight from the meadow varied from 18 to 40%. From 4 to 6 June 1996, on 11 and 13 March 1997 and in the period 16-20 May 1997, the amino acid distribution in dew showed much variation. The percentage fraction of arginine and proline in the hydrolysate increased greatly, whereas that of glycine and serine decreased. The large increase in proline and arginine in hydrolysate is attributable solely to the large amounts of free arginine and proline. This effect occurred in both 1996 and 1997 over several days at both sites at any one time and therefore appears confirmed.

  1. Thyroid peroxidase activity is inhibited by amino acids

    Directory of Open Access Journals (Sweden)

    D.P. Carvalho

    2000-03-01

    Full Text Available Normal in vitro thyroid peroxidase (TPO iodide oxidation activity was completely inhibited by a hydrolyzed TPO preparation (0.15 mg/ml or hydrolyzed bovine serum albumin (BSA, 0.2 mg/ml. A pancreatic hydrolysate of casein (trypticase peptone, 0.1 mg/ml and some amino acids (cysteine, tryptophan and methionine, 50 µM each also inhibited the TPO iodide oxidation reaction completely, whereas casamino acids (0.1 mg/ml, and tyrosine, phenylalanine and histidine (50 µM each inhibited the TPO reaction by 54% or less. A pancreatic digest of gelatin (0.1 mg/ml or any other amino acid (50 µM tested did not significantly decrease TPO activity. The amino acids that impair iodide oxidation also inhibit the TPO albumin iodination activity. The inhibitory amino acids contain side chains with either sulfur atoms (cysteine and methionine or aromatic rings (tyrosine, tryptophan, histidine and phenylalanine. Among the amino acids tested, only cysteine affected the TPO guaiacol oxidation reaction, producing a transient inhibition at 25 or 50 µM. The iodide oxidation inhibitory activity of cysteine, methionine and tryptophan was reversed by increasing iodide concentrations from 12 to 18 mM, while no such effect was observed when the cofactor (H2O2 concentration was increased. The inhibitory substances might interfere with the enzyme activity by competing with its normal substrates for their binding sites, binding to the free substrates or reducing their oxidized form.

  2. Silicone hydrogels grafted with natural amino acids for ophthalmological application.

    Science.gov (United States)

    Xu, Chen; He, Ruiyu; Xie, Binbin; Ismail, Muhammad; Yao, Chen; Luan, Jie; Li, Xinsong

    2016-09-01

    In this report, protein repelling silicone hydrogels with improved hydrophilicity were prepared by photo-polymerization of silicone-containing monomer and glycidyl methacrylate followed by grafting zwitterionic amino acids. The grafted silicone hydrogels possessed excellent hydrophilic surfaces due to the enrichment of amino acids, which was confirmed by attenuated total reflectance Fourier transform infrared spectroscopy, X-ray photoelectron spectroscopy, contact angle, and equilibrium water content measurements. Remarkable resistance to bovine serum albumin and lysozyme fouling was observed for the silicone hydrogels immobilized with neutrally charged amino acids because of the formation of zwitterionic surfaces with pairs of protonated secondary ammonium cations and deprotonated carboxyl anions. Meanwhile, the silicone hydrogels grafted with positively or negatively charged amino acids were able to repulse same charged protein with reduced deposition and attract oppositely charged protein with increased adsorption. Preliminary cytotoxicity test indicated that the zwitterionic silicone hydrogels were non-cytotoxic. Similarly, three types of natural amino acids, including serine, aspartic acid and histidine, modified silicone hydrogel contact lenses exhibited excellent hydrophilicity and non-damage to the rabbit's eyes, but only serine modified zwitterionic contact lens showed superior protein fouling resistance compared with the current commercial hydrogel contact lens, which may have great potential application in ophthalmology. PMID:27297564

  3. Amino acid composition in endothermic vertebrates is biased in the same direction as in thermophilic prokaryotes

    Directory of Open Access Journals (Sweden)

    Wang Guang-Zhong

    2010-08-01

    Full Text Available Abstract Background Among bacteria and archaea, amino acid usage is correlated with habitat temperatures. In particular, protein surfaces in species thriving at higher temperatures appear to be enriched in amino acids that stabilize protein structure and depleted in amino acids that decrease thermostability. Does this observation reflect a causal relationship, or could the apparent trend be caused by phylogenetic relatedness among sampled organisms living at different temperatures? And do proteins from endothermic and exothermic vertebrates show similar differences? Results We find that the observed correlations between the frequencies of individual amino acids and prokaryotic habitat temperature are strongly influenced by evolutionary relatedness between the species analysed; however, a proteome-wide bias towards increased thermostability remains after controlling for phylogeny. Do eukaryotes show similar effects of thermal adaptation? A small shift of amino acid usage in the expected direction is observed in endothermic ('warm-blooded' mammals and chicken compared to ectothermic ('cold-blooded' vertebrates with lower body temperatures; this shift is not simply explained by nucleotide usage biases. Conclusion Protein homologs operating at different temperatures have different amino acid composition, both in prokaryotes and in vertebrates. Thus, during the transition from ectothermic to endothermic life styles, the ancestors of mammals and of birds may have experienced weak genome-wide positive selection to increase the thermostability of their proteins.

  4. The properties of solid Zn(II)-amino acid complexes in the form of suspensions.

    Science.gov (United States)

    Dolińska, B

    2001-10-01

    An investigation was made into the experimental conditions for the formation of poorly soluble complexes of the divalent Zinc(II) combined with the following selected amino acids: tyrosine, tryptophan, cysteine, histidine, and alanine, in the form of suspensions for parenteral administration. The number of Zn(II)-binding sites in the amino acid (n) as well as the amino acid affinity to Zn(II) (Ka), were determined. Cysteine was found to have the highest number of Zn(II)-binding sites--3, whereas alanine the lowest--1. In the conditions described herein, Zn(II) amino acid complexes of diverse stability (durability) were obtained. The analysis of the kinetics of the binding revealed that the most stable complexes were those formed by Zn(II) in combination with tryptophan (Ka = 405.78 microM(-1) +/- 12.17), and with tyrosine (Ka = 343.88 microM +/- 22.35); whereas the least stable complexes were those formed by Zn(II) in combination with histidine (Ka = 29.90 microM +/- 4.78), and with alanine (Ka = 13.0 microM(-1) +/- 1.04). Cysteine formed complexes of intermediate stability (Ka = 168.53 microM(-1) +/- 12.36). The stability ofthe Zn(II) amino acid complexes obtained was conditioned by both the molecular weight (P = 0.033) of the amino acid and its isoelectric point (P < 0.001). PMID:11718265

  5. Absolute quantitation of proteins by Acid hydrolysis combined with amino Acid detection by mass spectrometry

    DEFF Research Database (Denmark)

    Mirgorodskaya, Olga A; Körner, Roman; Kozmin, Yuri P;

    2012-01-01

    Amino acid analysis is among the most accurate methods for absolute quantification of proteins and peptides. Here, we combine acid hydrolysis with the addition of isotopically labeled standard amino acids and analysis by mass spectrometry for accurate and sensitive protein quantitation....... Quantitation of less than 10 fmol of protein standards with errors below 10% has been demonstrated using this method (1)....

  6. Amino acid salt solutions for carbon dioxide capture

    OpenAIRE

    Majchrowicz, Magdalena Elzbieta

    2014-01-01

    Reactive absorption is a common process in the chemical industry and is used, among others, in the treatment of CO2 containing industrial gas streams. The current work was a part of a project with the aim to assess new reactive solvents based on amino acid salts for CO2 removal from industrial gas streams. Initially, a group of promising amino acid salts (taurine, sarcosine, L-proline, -alanine, 6-aminohexanoic acid and DL-methionine) was screened for their CO2 absorption kinetics, pKa value...

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

    Energy Technology Data Exchange (ETDEWEB)

    Atla, Shashi B. [Department of Earth and Environmental Sciences, National Chung Cheng University, Minhsiung, Chiayi 621, Taiwan (China); Wu, Min-Nan; Pan, Wei; Hsiao, Yu Tang [Department of Physics, National Chung Cheng University, Minhsiung, Chiayi 621, Taiwan (China); Sun, An-Cheng [Department of Chemical Engineering and Materials Science, Yuan Ze University, No. 135 Yuan-Tung Road, Chungli, Taoyuan 320, Taiwan (China); Tseng, Min-Jen [Department of Life Science, National Chung Cheng University, 168 University Road, Minhsiung, Chiayi 621, Taiwan (China); Chen, Yen-Ju [Department of Earth and Environmental Sciences, National Chung Cheng University, Minhsiung, Chiayi 621, Taiwan (China); Chen, Chien-Yen, E-mail: yen@eq.ccu.edu.tw [Department of Earth and Environmental Sciences, National Chung Cheng University, Minhsiung, Chiayi 621, Taiwan (China); Department of Advanced Institute of Manufacturing with High-tech Innovations, National Chung Cheng University, Minhsiung, Chiayi 621, Taiwan (China)

    2014-12-15

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

  8. Fungal Peptaibiotics: Assessing Potential Meteoritic Amino Acid Contamination

    Science.gov (United States)

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

    2010-01-01

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

  9. RESEARCH ON THE POLYCONDENSATION KINETICS OF ω-AMINO-ACIDS

    Institute of Scientific and Technical Information of China (English)

    WANG Baoren; SHI Manli; QIAN Chunqing

    1983-01-01

    In our previous report, it was discovered that the polycondensation of 9-amino-nonanoic acid follows second order from the beginning up to the extent of reaction, p, around 99%, and after which the reaction changes rapidly to third order. In this paper, we wish to report that this change of the reaction order from second to third occurred also in the polycondensation of 6aminocaproic acid and 11-amino-undecanoic acid. The transition region lay again at p around 99%.It may be concluded that this is a general rule in the polycondensation of the ω-amino-acids (monomers of the A-B type), and the controversial results that appeared in the literature may be cleared up by our experiments.

  10. Amino acids as corrosion inhibitors for copper in acidic medium: Experimental and theoretical study

    OpenAIRE

    Milošev Ingrid; Pavlinac Jasminka; Hodošček Milan; Lesar Antonija

    2013-01-01

    Experimental electrochemical methods combined with quantum chemical calculations and molecular dynamics simulations were used to investigate the possibility of use various amino acids as “green” corrosion inhibitors for copper in 0.5 M HCl solution. Among eleven amino acids studied, cysteine achieved the highest inhibitor effectiveness reaching 52% at 10 mM concentration. Other amino acids reached achieved effectiveness less than 25%, some of them even acte...

  11. Amino acid analogs IV:4-fluoroisoleucine.

    Science.gov (United States)

    Gershon, H; Shanks, L; Clarke, D D

    1978-05-01

    4-Fluoroisoleucine was produced by ammonolysis of 2-bromo-4-fluoro-3-methylpentanoic acid, which resulted from the bromofluorination of 4-methyl-2-pentenoic acid. It did not inhibit Plasmodium berghei in mice at 640 mg/kg and was not toxic to the animals. The fluoroamino acid inhibited Aspergillus niger, Trichoderma viride, Myrothecium verrucaria, Trichophyton mentagrophytes, and Mucor mucedo in Czapek solution agar at a concentration between 10(4) and 10(3) microgram/ml. Growth of Escherichia coli was inhibited 25% at 900 microgram/ml in a defined medium.

  12. Amino Acids as a Source of Organic Nitrogen in Antarctic Endolithic Microbial Communities

    Science.gov (United States)

    McDonald, G. D.; Sun, H. J.

    2002-12-01

    In the Antarctic Dry Valleys, cryptoendolithic microbial communities occur within porous sandstone rocks. Current understanding of the mechanisms of physiological adaptation of these communities to the harsh Antarctic environment is limited, because traditional methods of studying microbial physiology are very difficult to apply to organisms with extremely low levels of metabolic activity. In order to fully understand carbon and nitrogen cycling and nutrient uptake in cryptoendolithic communities, and the metabolic costs that the organisms incur in order to survive, it is necessary to employ molecular geochemical techniques such as amino acid analysis in addition to physiological methods. Low-molecular-weight biomolecules such as amino acids can be used as tracers of carbon and nitrogen uptake and loss by microbial communities living in solid-state matrices such as rock or sediment. We have measured the concentrations and D/L ratios for several amino acids as a function of depth in a large sandstone boulder. Concentrations of both free and bound amino acids decrease by more than two orders of magnitude from the surface to the visible base of the community (approximately 1.2 cm depth), while the D/L ratios of the amino acids increase from near zero to 0.2 or greater over the same depth interval. We interpret these data as an indication that one or more community members are selectively scavenging L-amino acids as the amino acids are transported through the rock by intermittently percolating meltwater. This is consistent with the known preference of lichens for amino acids as nitrogen sources rather than inorganic nitrogen under conditions of nutrient limitation. It is not yet clear whether there is also a contribution to amino acid uptake from heterotropic bacteria associated with the cryptoendolithic community. The increase in D/L ratios with depth observed in the rock is too great to be attributable solely to the natural occurrence of D-amino acids in bacteria

  13. Non-physiological amino acid (NPAA) therapy targeting brain phenylalanine reduction: pilot studies in PAHENU2 mice.

    Science.gov (United States)

    Vogel, Kara R; Arning, Erland; Wasek, Brandi L; Bottiglieri, Teodoro; Gibson, K Michael

    2013-05-01

    Transport of large neutral amino acids (LNAA) across the blood brain barrier (BBB) is facilitated by the L-type amino acid transporter, LAT1. Peripheral accumulation of one LNAA (e.g., phenylalanine (phe) in PKU) is predicted to increase uptake of the offending amino acid to the detriment of others, resulting in disruption of brain amino acid homeostasis. We hypothesized that selected non-physiological amino acids (NPAAs) such as DL-norleucine (NL), 2-aminonorbornane (NB; 2-aminobicyclo-(2,1,1)-heptane-2-carboxylic acid), 2-aminoisobutyrate (AIB), and N-methyl-aminoisobutyrate (MAIB), acting as competitive inhibitors of various brain amino acid transporters, could reduce brain phe in Pah (enu2) mice, a relevant murine model of PKU. Oral feeding of 5 % NL, 5 % AIB, 0.5 % NB and 3 % MAIB reduced brain phe by 56 % (p amino acids) were also observed, however, with MAIB displaying the mildest effects. Of interest, MAIB represents an inhibitor of the system A (alanine) transporter that primarily traffics small amino acids and not LNAAs. Our studies represent the first in vivo use of these NPAAs in Pah (enu2) mice, and provide proof-of-principle for their further preclinical development, with the long-term objective of identifying NPAA combinations and concentrations that selectively restrict brain phe transport while minimally impacting other LNAAs and downstream intermediates.

  14. Impact of dietary aromatic amino acids on osteoclastic activity.

    Science.gov (United States)

    Refaey, Mona El; Zhong, Qing; Ding, Ke-Hong; Shi, Xing-Ming; Xu, Jianrui; Bollag, Wendy B; Hill, William D; Chutkan, Norman; Robbins, Richard; Nadeau, Hugh; Johnson, Maribeth; Hamrick, Mark W; Isales, Carlos M

    2014-08-01

    We had shown that aromatic amino acid (phenylalanine, tyrosine, and tryptophan) supplementation prevented bone loss in an aging C57BL/6 mice model. In vivo results from the markers of bone breakdown suggested an inhibition of osteoclastic activity or differentiation. To assess osteoclastic differentiation, we examined the effects of aromatic amino acids on early /structural markers as vitronectin receptor, calcitonin receptor, and carbonic anhydrase II as well as, late/functional differentiation markers; cathepsin K and matrix metalloproteinase 9 (MMP-9). Our data demonstrate that the aromatic amino acids down-regulated early and late osteoclastic differentiation markers as measured by real time PCR. Our data also suggest a link between the vitronectin receptor and the secreted cathepsin K that both showed consistent effects to the aromatic amino acid treatment. However, the non-attachment related proteins, calcitonin receptor, and carbonic anhydrase II, demonstrated less consistent effects in response to treatment. Our data are consistent with aromatic amino acids down-regulating osteoclastic differentiation by suppressing remodeling gene expression thus contributing initially to the net increase in bone mass seen in vivo.

  15. FLU, an amino acid substitution model for influenza proteins

    Directory of Open Access Journals (Sweden)

    Gascuel Olivier

    2010-04-01

    Full Text Available Abstract Background The amino acid substitution model is the core component of many protein analysis systems such as sequence similarity search, sequence alignment, and phylogenetic inference. Although several general amino acid substitution models have been estimated from large and diverse protein databases, they remain inappropriate for analyzing specific species, e.g., viruses. Emerging epidemics of influenza viruses raise the need for comprehensive studies of these dangerous viruses. We propose an influenza-specific amino acid substitution model to enhance the understanding of the evolution of influenza viruses. Results A maximum likelihood approach was applied to estimate an amino acid substitution model (FLU from ~113, 000 influenza protein sequences, consisting of ~20 million residues. FLU outperforms 14 widely used models in constructing maximum likelihood phylogenetic trees for the majority of influenza protein alignments. On average, FLU gains ~42 log likelihood points with an alignment of 300 sites. Moreover, topologies of trees constructed using FLU and other models are frequently different. FLU does indeed have an impact on likelihood improvement as well as tree topologies. It was implemented in PhyML and can be downloaded from ftp://ftp.sanger.ac.uk/pub/1000genomes/lsq/FLU or included in PhyML 3.0 server at http://www.atgc-montpellier.fr/phyml/. Conclusions FLU should be useful for any influenza protein analysis system which requires an accurate description of amino acid substitutions.

  16. Detection of COL III in parchment by amino acid analysis.

    Science.gov (United States)

    Sommer, Dorte V P; Larsen, René

    2016-01-01

    Cultural heritage parchments made from the reticular dermis of animals have been subject to studies of deterioration and conservation by amino acid analysis. The reticular dermis contains a varying mixture of collagen I and III (COL I and III). When dealing with the results of the amino acid analyses, till now the COL III content has not been taken into account. Based on the available amino acid sequences, we present a method for determining the amount of COL III in the reticular dermis of new and historical parchments calculated from the ratio of Ile/Val. We find COL III contents between 7 and 32 % in new parchments and between 0.2 and 40 % in the historical parchments. This is consistent with results in the literature. The varying content of COL III has a significant influence on the uncertainty of the amino acid analysis. Although we have not found a simple correlation between the COL III content and the degree of deterioration, our results show that this question must be taken into consideration in future studies of the chemical and physical deterioration of parchment measured by amino acid analysis and other analytical methods.

  17. Amino acid containing glass-ionomer cement for orthopedic applications

    Science.gov (United States)

    Wu, Wei

    Amino acid containing glass-ionomer cements were synthesized, formulated, and evaluated for orthopedic application. The formulation of different amino acid containing glass-ionomer bone cements was optimized, and conventional and resin-modified glass-ionomer bone cements were compared. Properties of interest included handling characteristics, physical and chemical properties, and mechanical strength of the bone cement. The study was based on the synthesis of different vinyl containing amino acids, different polyelectrolytes containing these amino acid residues, and different resin-modified polyelectrolytes, as well as formulation and evaluation of conventional and resin-modified glass-ionomer bone cements using these polyelectrolytes. Systematic preparation of polyelectrolytes and formulation of glass-ionomer bone cements were essential features of this work, since we anticipated that the mechanical properties of the glass-ionomer bone cements could be strongly affected by the nature of the polyelectrolytes and formulation. Mechanical properties were evaluated in a screw driven mechanical testing machine, and structure-property relationships were determined by scanning electron microscopic (SEM) observation of the fracture surface of the specimens. How the structure of polyelectrolytes, such as different amino acid residues, molecular weight, different modifying resin, and formulation of glass-ionomer bone cement, affected the mechanical properties was also studied.

  18. Micelle-bound structures and dynamics of the hinge deleted analog of melittin and its diastereomer: implications in cell selective lysis by D-amino acid containing antimicrobial peptides.

    Science.gov (United States)

    Saravanan, Rathi; Bhunia, Anirban; Bhattacharjya, Surajit

    2010-02-01

    Melittin, the major component of the honey bee venom, is a 26-residue hemolytic and membrane active peptide. Structures of melittin determined either in lipid environments by NMR or by use of X-ray demonstrated two helical regions at the N- and C-termini connected by a hinge or a bend at the middle. Here, we show that deletion of the hinge residues along with two C-terminal terminal Gln residues (Q25 and Q26), yielding a peptide analog of 19-residue or Mel-H, did not affect antibacterial activity but resulted in a somewhat reduced hemolytic activity. A diastereomer of Mel-H or Mel-(d)H containing d-amino acids [(d)V5, (d)V8, (d)L11 and (d)K16] showed further reduction in hemolytic activity without lowering antibacterial activity. We have carried out NMR structures, dynamics (H-D exchange and proton relaxation), membrane localization by spin labeled lipids, pulse-field-gradient (PFG) NMR and isothermal titration calorimetry (ITC) in dodecylphosphocholine (DPC) micelles, as a mimic to eukaryotic membrane, to gain insights into cell selectivity of these melittin analogs. PFG-NMR showed Mel-H and Mel-(d)H both were similarly partitioned into DPC micelles. ITC demonstrated that Mel-H and Mel-(d)H interact with DPC with similar affinity. The micelle-bound structure of Mel-H delineated a straight helical conformation, whereas Mel-(d)H showed multiple beta-turns at the N-terminus and a short helix at the C-terminus. The backbone amide-proton exchange with solvent D(2)O demonstrated a large difference in dynamics between Mel-H and Mel-(d)H, whereby almost all backbone protons of Mel-(d)H showed a much faster rate of exchange as compared to Mel-H. Proton T(1) relaxation had suggested a mobile backbone of Mel-(d)H peptide in DPC micelles. Resonance perturbation by paramagnetic lipids indicated that Mel-H inserted deeper into DPC micelles, whereas Mel-(d)H is largely located at the surface of the micelle. Taken together, results presented in this study demonstrated that the

  19. Synthesis and Cytotoxic Activity on Human Cancer Cells of Novel Isoquinolinequinone-Amino Acid Derivatives.

    Science.gov (United States)

    Valderrama, Jaime A; Delgado, Virginia; Sepúlveda, Sandra; Benites, Julio; Theoduloz, Cristina; Buc Calderon, Pedro; Muccioli, Giulio G

    2016-09-08

    A variety of aminoisoquinoline-5,8-quinones bearing α-amino acids moieties were synthesized from 3-methyl-4-methoxycarbonylisoquinoline-5,8-quinone and diverse l- and d-α-amino acid methyl esters. The members of the series were evaluated for their cytotoxic activity against normal and cancer cell lines by using the (3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide) (MTT) assay. From the current investigation, structure-activity relationships demonstrate that the location and structure of the amino acid fragment plays a significant role in the cytotoxic effects. Moderate to high cytotoxic activity was observed and four members, derived from l-alanine, l-leucine, l-phenylalanine, and d-phenylalanine, were selected as promising compounds by their IC50 ranging from 0.5 to 6.25 μM and also by their good selectivity indexes (≥2.24).

  20. Composition of antioxidants and amino acids in Stevia leaf infusions.

    Science.gov (United States)

    Periche, Angela; Koutsidis, Georgios; Escriche, Isabel

    2014-03-01

    Stevia, a non-caloric natural sweetener with beneficial properties and considerable antioxidants and amino acids, is increasingly consumed as an infusion. This work evaluates the influence of the conditions (temperature: 50, 70 or 90 °C and time: 1, 5, 20 or 40 min) applied to obtain Stevia infusions, on antioxidants (total phenols, flavonoids and antioxidant activity) and amino acids. The total concentration of the eleven amino acids found was 11.70 mg/g in dried leaves and from 6.84 to 9.11 mg/g per gram of Stevia in infusions. However, infusions showed higher levels of certain amino acids (alanine, asparagine, leucine and proline), and greater values of the three antioxidant parameters in comparison with dry leaves. Temperature had more influence (minimum values at 50 °C and maximum at 90 °C) than time in the case of antioxidants. At 90 °C there were no important increases in the extraction of antioxidant compounds after 5 min; each gram of Stevia had 117 mg trolox (total antioxidant activity), 90 mg gallic acid (total phenols) and 56 mg catechin equivalents (flavonoids). Varying the temperature and time conditions no notable differences were observed in the concentrations of the majority of amino acids. However, the infusion treatment at 90 °C for 5 min was the best, as it gave the highest yield of 8 of the 11 amino acids. Therefore, with respect to the compounds analyzed in this study, the best way to obtain Stevia leaf infusions is the same as the domestic process, almost boiling water for a short time.

  1. Role of mitochondrial transamination in branched chain amino acid metabolism

    Energy Technology Data Exchange (ETDEWEB)

    Hutson, S.M.; Fenstermacher, D.; Mahar, C.

    1988-03-15

    Oxidative decarboxylation and transamination of 1-/sup 14/C-branched chain amino and alpha-keto acids were examined in mitochondria isolated from rat heart. Transamination was inhibited by aminooxyacetate, but not by L-cycloserine. At equimolar concentrations of alpha-ketoiso(1-/sup 14/C)valerate (KIV) and isoleucine, transamination was increased by disrupting the mitochondria with detergent which suggests transport may be one factor affecting the rate of transamination. Next, the subcellular distribution of the aminotransferase(s) was determined. Branched chain aminotransferase activity was measured using two concentrations of isoleucine as amino donor and (1-/sup 14/C)KIV as amino acceptor. The data show that branched chain aminotransferase activity is located exclusively in the mitochondria in rat heart. Metabolism of extramitochondrial branched chain alpha-keto acids was examined using 20 microM (1-/sup 14/C)KIV and alpha-ketoiso(1-/sup 14/C)caproate (KIC). There was rapid uptake and oxidation of labeled branched chain alpha-keto acid, and, regardless of the experimental condition, greater than 90% of the labeled keto acid substrate was metabolized during the 20-min incubation. When a branched chain amino acid (200 microM) or glutamate (5 mM) was present, 30-40% of the labeled keto acid was transaminated while the remainder was oxidized. Provision of an alternate amino acceptor in the form of alpha-keto-glutarate (0.5 mM) decreased transamination of the labeled KIV or KIC and increased oxidation. Metabolism of intramitochondrially generated branched chain alpha-keto acids was studied using (1-/sup 14/C)leucine and (1-/sup 14/C)valine. Essentially all of the labeled branched chain alpha-keto acid produced by transamination of (1-/sup 14/C)leucine or (1-/sup 14/C)valine with a low concentration of unlabeled branched chain alpha-keto acid (20 microM) was oxidized.

  2. THz time-domain spectroscopy of amino acids

    Institute of Scientific and Technical Information of China (English)

    WANG Weining; YUE Weiwei; YAN Haitao; ZHANG Cunlin; ZHAO Guozhong

    2005-01-01

    The optical characteristics of four kinds of amino acids (tyrosine, arginine, histidine and glutamine) filled with nitrogen at room temperature were studied by THz time-domain spectroscopy (THz-TDS). Well-resolved absorption and refractive spectrums between 0.1 and 2.8 THz were obtained based on the physical model for extracting the optical parameters of materials in THz range. The results not only fill up the spectra gap of amino acids in far-infrared range, supply data for amino acid molecular identification and conformation analysis, but also demonstrate significantly potential to promote the research and application of biological materials in bio-chemical and medical fields by THz-TDS.

  3. Systematic Exploration of an Efficient Amino Acid Substitution Matrix: MIQS.

    Science.gov (United States)

    Tomii, Kentaro; Yamada, Kazunori

    2016-01-01

    Amino acid sequence comparisons to find similarities between proteins are fundamental sequence information analyses for inferring protein structure and function. In this study, we improve amino acid substitution matrices to identify distantly related proteins. We systematically sampled and benchmarked substitution matrices generated from the principal component analysis (PCA) subspace based on a set of typical existing matrices. Based on the benchmark results, we identified a region of highly sensitive matrices in the PCA subspace using kernel density estimation (KDE). Using the PCA subspace, we were able to deduce a novel sensitive matrix, called MIQS, which shows better detection performance for detecting distantly related proteins than those of existing matrices. This approach to derive an efficient amino acid substitution matrix might influence many fields of protein sequence analysis. MIQS is available at http://csas.cbrc.jp/Ssearch/ . PMID:27115635

  4. Amino acid sequences of proteins from Leptospira serovar pomona

    Directory of Open Access Journals (Sweden)

    Alves Selmo F

    2000-01-01

    Full Text Available This report describes a partial amino acid sequences from three putative outer envelope proteins from Leptospira serovar pomona. In order to obtain internal fragments for protein sequencing, enzymatic and chemical digestion was performed. The enzyme clostripain was used to digest the proteins 32 and 45 kDa. In situ digestion of 40 kDa molecular weight protein was accomplished using cyanogen bromide. The 32 kDa protein generated two fragments, one of 21 kDa and another of 10 kDa that yielded five residues. A fragment of 24 kDa that yielded nineteen residues of amino acids was obtained from 45 kDa protein. A fragment with a molecular weight of 20 kDa, yielding a twenty amino acids sequence from the 40 kDa protein.

  5. Spectrofluorimetric study of the interaction of ciprofloxacin with amino acids in aqueous solution following solvatochromic studies

    Science.gov (United States)

    Alizadeh, Kamal; Mobarrez, Mahsa; Ganjali, Mohammad Reza; Norouzi, Parviz; Chaichi, Mohammad Javad

    Complexation of a fluoroquinolone derivative (ciprofloxacin), L, and some amino acids has been studied using spectrofluorimetric method. Results indicated that ciprofloxacin have a greater tendency to form a 1:1 complex with aspartic acid and arginine than the other tested molecules. The fluorescence of ciprofloxacin exhibits quenching process while it has been titrated with these amino acids. Formation constant values (Kf) for complex formed between ciprofloxacin and amino acids were also calculated. Thermodynamic parameters such as ΔG°, ΔH° and ΔS° were studied too. Possible reasons for the observed stability sequence were discussed based on the structures proposed for the resulting complexes. Besides the solution studies, solvatochromic properties of the ciprofloxacin are discussed by studying its spectra in a selection of different solvents.

  6. The Studies of the Reactions of 2, 4, 6-Triphenylpyrylium Tetrafluoroborate with Amino Acids

    Institute of Scientific and Technical Information of China (English)

    Shrong Shi LIN; Xian Jing KONG; Jing Yuan LIU; Cheng Yong LI

    2003-01-01

    The reactions of triphenylpyrylium salt 1 with various amino acids were explored andcompared. The reactions with most α-amino acids yielded decarboxylation products 2 viadecarboxylation. The reactions with glutamic acid, lysine and ACC (1-aminocyclopropyl-carboxylic acid) gave triphenylpyridine 8, dimer 9 and acid 5a-acc, respectively. The reactionswith β and γ-amino acids yielded triphenylpyridine by intramolecular elimination.

  7. AMINO ACID METABOLISM IN COWS DURING THE TRANSITION PERIOD IN BALANCING DIET ON THE EXCHANGE PROTEIN AND DIGESTIBLE AMINO ACIDS

    Directory of Open Access Journals (Sweden)

    Ryadchikov V. G.

    2014-02-01

    Full Text Available Application of a factorial method for determining the needs in metabolic protein and essential amino acids, helps to deepen knowledge on physiology of protein and amino acid supply and allow to improve the standards for dairy cows during the transition period; in insufficient of metabolic protein and essential amino acids increased coefficients of their transformation into net protein and absorptive amino acids as a result of mobilization of body of cows; with an optimal protein nutrition their transformation in net milk protein, lysine and methionine accordingly amounted to 0.67, 0,83 and 0,82. The most significant changes in the concentration of methionine, proline, glutamate, glutamine, glycine were observed in cows before calving and immediately after birth, stabilization of their level starts with a 24 lactation day, that is connected with the peculiarities of the feeding behavior of the cows and the gradual intensification of the processes of metabolism and milk production. To control the status of protein metabolism we have offered benchmarks compositions of free amino acids in cows’ blood plasma phases: 21-0 days before calving, 0-21 and 22-120 days after calving

  8. Solid state radiolysis of amino acids in an astrochemical perspective

    Energy Technology Data Exchange (ETDEWEB)

    Cataldo, Franco, E-mail: franco.cataldo@fastwebnet.i [Istituto Nazionale di Astrofisica-Osservatorio Astrofisica di Catania, Via S. Sofia 78, 95123 Catania (Italy); Lupi Chemical Research, Via Casilina 1626/A, 00133 Rome (Italy); Angelini, Giancarlo [Istituto di Metodologie Chimiche, CNR, Via Salaria Km 29300, 00016 Monterotondo Stazione, Rome (Italy); Iglesias-Groth, Susana [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain); Manchado, Arturo [Instituto de Astrofisica de Canarias, Via Lactea s/n, E-38200, La Laguna, Tenerife (Spain) and CSIC (Spain)

    2011-01-15

    The aliphatic amino acids L-alanine and L-leucine and the aromatic amino acids L-phenylalanine, L-tyrosine and L-tryptophan were irradiated in the solid state to a dose of 3.2 MGy. The degree of decomposition was measured by differential scanning calorimetry (DSC). Furthermore the degree of radioracemization was measured by optical rotatory dispersion (ORD) spectroscopy. From the DSC measurement a radiolysis rate constant k and the half life T{sub 1/2} for each amino acid have been determined and extrapolated to a dose of 14 MGy, which corresponds to the expected total dose delivered by the decay of radionuclides to the organic molecules present in comets and asteroids in 4.6x10{sup 9} years, the age of the Solar System. It is shown that all the amino acids studied can survive a radiation dose of 14 MGy although they are reduced to 1/4-1/5 of their original value they had at the beginning of the history of the Solar System. Consequently, the amount of alanine or leucine found today in the meteorites known as carbonaceous chondrites is just 1/4-1/5 of the amount originally present at the epoch of the formation of the Solar System 4.6x10{sup 9} years ago. Among the amino acids studied, tyrosine shows the highest radiation resistance while tryptophan does not combine its relatively high radiation resistance with an elevated level of radioracemization resistance. Apart from the exception of tryptophan, it is shown that the radiolysis rate constants k of all the amino acids studied are in reasonable agreement with the radioracemization rate constant k{sub rac}.

  9. Solid state radiolysis of amino acids in an astrochemical perspective

    Science.gov (United States)

    Cataldo, Franco; Angelini, Giancarlo; Iglesias-Groth, Susana; Manchado, Arturo

    2011-01-01

    The aliphatic amino acids L-alanine and L-leucine and the aromatic amino acids L-phenylalanine, L-tyrosine and L-tryptophan were irradiated in the solid state to a dose of 3.2 MGy. The degree of decomposition was measured by differential scanning calorimetry (DSC). Furthermore the degree of radioracemization was measured by optical rotatory dispersion (ORD) spectroscopy. From the DSC measurement a radiolysis rate constant k and the half life T1/2 for each amino acid have been determined and extrapolated to a dose of 14 MGy, which corresponds to the expected total dose delivered by the decay of radionuclides to the organic molecules present in comets and asteroids in 4.6×109 years, the age of the Solar System. It is shown that all the amino acids studied can survive a radiation dose of 14 MGy although they are reduced to 1/4-1/5 of their original value they had at the beginning of the history of the Solar System. Consequently, the amount of alanine or leucine found today in the meteorites known as carbonaceous chondrites is just 1/4-1/5 of the amount originally present at the epoch of the formation of the Solar System 4.6×109 years ago. Among the amino acids studied, tyrosine shows the highest radiation resistance while tryptophan does not combine its relatively high radiation resistance with an elevated level of radioracemization resistance. Apart from the exception of tryptophan, it is shown that the radiolysis rate constants k of all the amino acids studied are in reasonable agreement with the radioracemization rate constant krac.

  10. Transport of aromatic amino acids by Brevibacterium linens.

    OpenAIRE

    Boyaval, P; Moreira, E; Desmazeaud, M. J.

    1983-01-01

    Whole metabolizing Brevibacterium linens cells were used to study the transport of aromatic amino acids. Kinetic results followed the Michaelis-Menten equation with apparent Km values for phenylalanine, tyrosine, and tryptophan of 24, 3.5, and 1.8 microM. Transport of these amino acids was optimum at pH 7.5 and 25 degrees C for phenylalanine and pH 8.0 and 35 degrees C for tyrosine and tryptophan. Crossed inhibitions were all noncompetitive. The only marked stereospecificity was for the L for...

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-22

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

  12. Regulation of intestinal mucosal growth by amino acids.

    Science.gov (United States)

    Ray, Ramesh M; Johnson, Leonard R

    2014-03-01

    Amino acids, especially glutamine (GLN) have been known for many years to stimulate the growth of small intestinal mucosa. Polyamines are also required for optimal mucosal growth, and the inhibition of ornithine decarboxylase (ODC), the first rate-limiting enzyme in polyamine synthesis, blocks growth. Certain amino acids, primarily asparagine (ASN) and GLN stimulate ODC activity in a solution of physiological salts. More importantly, their presence is also required before growth factors and hormones such as epidermal growth factor and insulin are able to increase ODC activity. ODC activity is inhibited by antizyme-1 (AZ) whose synthesis is stimulated by polyamines, thus, providing a negative feedback regulation of the enzyme. In the absence of amino acids mammalian target of rapamycin complex 1 (mTORC1) is inhibited, whereas, mTORC2 is stimulated leading to the inhibition of global protein synthesis but increasing the synthesis of AZ via a cap-independent mechanism. These data, therefore, explain why ASN or GLN is essential for the activation of ODC. Interestingly, in a number of papers, AZ has been shown to inhibit cell proliferation, stimulate apoptosis, or increase autophagy. Each of these activities results in decreased cellular growth. AZ binds to and accelerates the degradation of ODC and other proteins shown to regulate proliferation and cell death, such as Aurora-A, Cyclin D1, and Smad1. The correlation between the stimulation of ODC activity and the absence of AZ as influenced by amino acids is high. Not only do amino acids such as ASN and GLN stimulate ODC while inhibiting AZ synthesis, but also amino acids such as lysine, valine, and ornithine, which inhibit ODC activity, increase the synthesis of AZ. The question remaining to be answered is whether AZ inhibits growth directly or whether it acts by decreasing the availability of polyamines to the dividing cells. In either case, evidence strongly suggests that the regulation of AZ synthesis is the

  13. 21 CFR 172.320 - Amino acids.

    Science.gov (United States)

    2010-04-01

    ...-Leucine L-Lysine DL-Methionine (not for infant foods) L-Methionine L-Phenylalanine L-Proline L-Serine L... Aminoacetic acid (glycine) L-Leucine DL-Methionine L-Methionine L-Tryptophan L-Phenylalanine L-Proline L... DL-Methionine 3.1 L-Phenylalanine 5.8 L-Proline 4.2 L-Serine 8.4 L-Threonine 5.0 L-Tryptophan 1.6...

  14. Amino Acids, Aromatic Compounds, and Carboxylic Acids: How Did They Get Their Common Names?

    Science.gov (United States)

    Leung, Sam H.

    2000-01-01

    Surveys the roots of the common names of organic compounds most likely to be encountered by undergraduate organic chemistry students. Includes information for 19 amino acids, 17 aromatic compounds, and 21 carboxylic acids. (WRM)

  15. Genetic and genotype × environment interaction effects for the content of seven essential amino acids in indica rice

    Indian Academy of Sciences (India)

    J. G. Wu; C. H. Shi; X. M. Zhang; T. Katsura

    2004-08-01

    It is necessary for rice breeders to understand the genetic basis of nutrient quality traits of rice. Essential amino acids are most important in determining the nutrient quality of rice grain and can affect the health of people who depend on rice as a staple food. In view of the paucity of genetic information available on essential amino acids in indica rice, we estimated the genetic main effects and genotype × environment (G × E) interaction effects on the content of essential amino acids. Nine cytoplasmic male sterile lines as females and five restorer lines as males were introduced in a North Carolina II design across environments. Estimates of the content of the essential amino acids valine, methionine, leucine and phenylalanine showed that they were mainly controlled by genetic main effects, while the contents of threonine, cysteine and isoleucine were mainly affected by G × E effects. In the case of genetic main effects, both cytoplasmic and maternal genetic effects were predominant for all essential amino acids, indicating that selection for improving essential amino acid content based on maternal performance would be more effective than that based on seeds. The total narrow-sense heritabilities were high and ranged from 0.72 to 0.83. Since general heritabilities for these essential amino acids (except for cysteine) were found to be much larger than G × E interaction heritability, the improvement of content of most essential amino acids under selection would be expected under various environments. Rice varieties such as Zhenan 3, Yinchao 1, T49, 26715, 102 and 1391 should be selected as optimal parents for increasing the content of most essential amino acids, while the total genetic effects from Zhexie 2, Xieqingzao, Gangchao 1, V20, Zuo 5 and Zhenshan 97 were mainly negative and these parents could decrease the contents of most essential amino acids.

  16. Transport and signaling via the amino acid binding site of the yeast Gap1 amino acid transceptor.

    Science.gov (United States)

    Van Zeebroeck, Griet; Bonini, Beatriz Monge; Versele, Matthias; Thevelein, Johan M

    2009-01-01

    Transporter-related nutrient sensors, called transceptors, mediate nutrient activation of signaling pathways through the plasma membrane. The mechanism of action of transporting and nontransporting transceptors is unknown. We have screened 319 amino acid analogs to identify compounds that act on Gap1, a transporting amino acid transceptor in yeast that triggers activation of the protein kinase A pathway. We identified competitive and noncompetitive inhibitors of transport, either with or without agonist action for signaling, including nontransported agonists. Using substituted cysteine accessibility method (SCAM) analysis, we identified Ser388 and Val389 as being exposed into the amino acid binding site, and we show that agonist action for signaling uses the same binding site as used for transport. Our results provide the first insight, to our knowledge, into the mechanism of action of transceptors. They indicate that signaling requires a ligand-induced specific conformational change that may be part of but does not require the complete transport cycle. PMID:19060912

  17. Paramagnetic relaxation enhancement of membrane proteins by incorporation of the metal-chelating unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA)

    Energy Technology Data Exchange (ETDEWEB)

    Park, Sang Ho; Wang, Vivian S.; Radoicic, Jasmina; Angelis, Anna A. De; Berkamp, Sabrina; Opella, Stanley J., E-mail: sopella@ucsd.edu [University of California, San Diego, Department of Chemistry and Biochemistry (United States)

    2015-04-15

    The use of paramagnetic constraints in protein NMR is an active area of research because of the benefits of long-range distance measurements (>10 Å). One of the main issues in successful execution is the incorporation of a paramagnetic metal ion into diamagnetic proteins. The most common metal ion tags are relatively long aliphatic chains attached to the side chain of a selected cysteine residue with a chelating group at the end where it can undergo substantial internal motions, decreasing the accuracy of the method. An attractive alternative approach is to incorporate an unnatural amino acid that binds metal ions at a specific site on the protein using the methods of molecular biology. Here we describe the successful incorporation of the unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) into two different membrane proteins by heterologous expression in E. coli. Fluorescence and NMR experiments demonstrate complete replacement of the natural amino acid with HQA and stable metal chelation by the mutated proteins. Evidence of site-specific intra- and inter-molecular PREs by NMR in micelle solutions sets the stage for the use of HQA incorporation in solid-state NMR structure determinations of membrane proteins in phospholipid bilayers.

  18. Paramagnetic relaxation enhancement of membrane proteins by incorporation of the metal-chelating unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA)

    International Nuclear Information System (INIS)

    The use of paramagnetic constraints in protein NMR is an active area of research because of the benefits of long-range distance measurements (>10 Å). One of the main issues in successful execution is the incorporation of a paramagnetic metal ion into diamagnetic proteins. The most common metal ion tags are relatively long aliphatic chains attached to the side chain of a selected cysteine residue with a chelating group at the end where it can undergo substantial internal motions, decreasing the accuracy of the method. An attractive alternative approach is to incorporate an unnatural amino acid that binds metal ions at a specific site on the protein using the methods of molecular biology. Here we describe the successful incorporation of the unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) into two different membrane proteins by heterologous expression in E. coli. Fluorescence and NMR experiments demonstrate complete replacement of the natural amino acid with HQA and stable metal chelation by the mutated proteins. Evidence of site-specific intra- and inter-molecular PREs by NMR in micelle solutions sets the stage for the use of HQA incorporation in solid-state NMR structure determinations of membrane proteins in phospholipid bilayers

  19. Feeding responses by female Pieris brassicae butterflies to carbohydrates and amino acids

    NARCIS (Netherlands)

    Romeis, J.; Wäckers, F.L.

    2000-01-01

    Most Lepidoptera feed during the adult stage on carbohydrate-rich food sources, primarily floral nectar. However, little is known about the factors leading to the acceptance of a possible food source. It is reported that butterflies select for nectar rich in sucrose and amino acids. This suggests th

  20. Feeding responses by female Pieris brassicae butterflies to carbohydrates and amino acids

    NARCIS (Netherlands)

    Romeis, J.; Wäckers, F.L.

    2000-01-01

    Most Lepidoptera feed during the adult stage on carbohydrate- rich food sources, primarily floral nectar. However, little is known about the factors leading to the acceptance of a possible food source. It is reported that butterflies select for nectar rich in sucrose and amino acids. This suggests t

  1. A modular synthesis of dithiocarbamate pendant unnatural α-amino acids

    Science.gov (United States)

    Unnatural α-amino acids containing dithiocarbamate side chains were synthesized by a one-pot reaction of in-situ generated dithiocarbamate anions with sulfamidates. A wide range of these anions participated in the highly regio- and stereo-selective ring opening of sulfamidates to...

  2. 1,2,3-triazolyl amino acids as AMPA receptor ligands

    DEFF Research Database (Denmark)

    Stanley, Nathan J.; Pedersen, Daniel Sejer; Nielsen, Birgitte;

    2010-01-01

    The central nervous system glutamate receptors are an important target for drug discovery. Herein we report initial investigations into the synthesis and glutamate receptor activity of 1,2,3-triazolyl amino acids. Two compounds were found to be selective AMPA receptor ligands, which warrant further...

  3. Coupling of Carbon Dioxide with Epoxides Catalyzed by Amino Acid Hydrochloride Salts

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Using amino acid hydrochloride salt as a catalyst, the coupling reaction of CO2 with epoxides could proceed smoothly to give cyclic carbonates in very good yields and high selectivity. The reaction conditions such as the pressure of carbon dioxide, reaction temperature, time and catalyst loading were carefully investigated.

  4. Evolutionary anatomies of positions and types of disease-associated and neutral amino acid mutations in the human genome

    Directory of Open Access Journals (Sweden)

    Subramanian Sankar

    2006-12-01

    Full Text Available Abstract Background Amino acid mutations in a large number of human proteins are known to be associated with heritable genetic disease. These disease-associated mutations (DAMs are known to occur predominantly in positions essential to the structure and function of the proteins. Here, we examine how the relative perpetuation and conservation of amino acid positions modulate the genome-wide patterns of 8,627 human disease-associated mutations (DAMs reported in 541 genes. We compare these patterns with 5,308 non-synonymous Single Nucleotide Polymorphisms (nSNPs in 2,592 genes from primary SNP resources. Results The abundance of DAMs shows a negative relationship with the evolutionary rate of the amino acid positions harboring them. An opposite trend describes the distribution of nSNPs. DAMs are also preferentially found in the amino acid positions that are retained (or present in multiple vertebrate species, whereas the nSNPs are over-abundant in the positions that have been lost (or absent in the non-human vertebrates. These observations are consistent with the effect of purifying selection on natural variation, which also explains the existence of lower minor nSNP allele frequencies at highly-conserved amino acid positions. The biochemical severity of the inter-specific amino acid changes is also modulated by natural selection, with the fast-evolving positions containing more radical amino acid differences among species. Similarly, DAMs associated with early-onset diseases are more radical than those associated with the late-onset diseases. A small fraction of DAMs (10% overlap with the amino acid differences between species within the same position, but are biochemically the most conservative group of amino acid differences in our datasets. Overlapping DAMs are found disproportionately in fast-evolving amino acid positions, which, along with the conservative nature of the amino acid changes, may have allowed some of them to escape natural

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

    Energy Technology Data Exchange (ETDEWEB)

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

    2016-03-22

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

  6. Analysis of Peptides and Conjugates by Amino Acid Analysis

    DEFF Research Database (Denmark)

    Højrup, Peter

    2015-01-01

    Amino acid analysis is a highly accurate method for characterization of the composition of synthetic peptides. Together with mass spectrometry, it gives a reliable control of peptide quality and quantity before conjugation and immunization.Peptides are hydrolyzed, preferably in gas phase, with 6 M...... HCl at 110 °C for 20-24 h and the resulting amino acids analyzed by ion-exchange chromatography with post-column ninhydrin derivatization. Depending on the hydrolysis conditions, tryptophan is destroyed, and cysteine also, unless derivatized, and the amides, glutamine and asparagine, are deamidated to...... glutamic acid and aspartic acid, respectively. Three different ways of calculating results are suggested, and taking the above limitations into account, a quantitation better than 5 % can usually be obtained....

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

    Directory of Open Access Journals (Sweden)

    Xiaochuang Cao

    Full Text Available 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

  8. Antibacterial Activity of Copper and Cobalt Amino Acids Complexes

    Directory of Open Access Journals (Sweden)

    ANDREEA STĂNILĂ

    2011-11-01

    Full Text Available The antibacterial properties of differently copper and cobalt amino acids complexes on agar plates was investigated in the present study. The antibacterial activity of amino acid complexes was evaluated against on three bacteria strains (Escherichia coli, Bacillus cereus, Micrococcus luteus. Generally, the amino acids complexes were mainly active against gram-positive organisms, species like Micrococcus luteus being the most susceptible strain tested. It was registered a moderate antibacterial activity against Bacillus cereus. The microorganisms Escherichia coli, which are already known to be multi-resistant to drugs, were also resistant to the amino acids complexes but also to the free salts tested. Escherichia coli were susceptible only to the CoCl2 and copper complex with phenylalanine. The complexes with leucine and histidine seem to be more active than the parent free ligand against one or more bacterial species. Moderate activity was registered in the case of complexes with methionine and phenylalanine. From the complexes tested less efficient antibacterial activity was noted in the case of complexes with lysine and valine. These results show that cobalt and copper complexes have an antibacterial activity and suggest their potential application as antibacterial agents.

  9. Photostability of amino acids: photodissociation dynamics of phenylalanine chromophores.

    Science.gov (United States)

    Tseng, Chien-Ming; Lin, Ming-Fu; Yang, Yi Lin; Ho, Yu Chieh; Ni, Chi-Kung; Chang, Jia-Lin

    2010-05-21

    The theoretical prediction of H atom elimination on the excited state of phenol, imidazole and indole, the respective chromophores for the amino acids tyrosine, histidine and tryptophan, and the confirmation of theoretical prediction by experimental observations have a great impact on the explanation of photostability of amino acids upon irradiation with UV photons. On the other hand, no theoretical prediction of the excited state photodissociation dynamics has been made on the other aromatic amino acid, phenylalanine. In this work, photodissociation dynamics for various phenylalanine chromophores, including, phenylethylamine, N-methyl-phenylethylamine, and N-acetyl phenylalanine methyl ester was investigated in a molecular beam at 248 and 193 nm using multimass ion imaging techniques. The major dissociation channel for these compounds is the C-C bond cleavage. However, the photofragment translational energy distribution of phenylethylamine contains two components. The slow component corresponds to the dissociation on the ground state surface after internal conversion, and the fast component represents the dissociation from an excited state with a large exit barrier. The competition between the dissociation on the ground state and on the excited state changes as the size of chromophores increases. Internal conversion to the ground state prior to dissociation becomes the major nonradiative process for large chromophores. This study reveals the size-dependent photostability for these amino acid chromophores.

  10. Transcriptional regulation of central amino acid metabolism in Lactococcus lactis

    NARCIS (Netherlands)

    Larsen, Rasmus

    2005-01-01

    This thesis describes the functional characterisation of the transcriptional regulators GlnR, ArgR and AhrC of Lactococcus lactis, which are responsible for the control of genes involved in the metabolism of the amino acids glutamine, glutamate and arginine. A chromosomal glnR deletion mutant was ma

  11. Induction of DNA damage by oxidised amino acids and proteins

    DEFF Research Database (Denmark)

    Luxford, Catherine; Dean, Roger T; Davies, Michael Jonathan

    2002-01-01

    Exposure of amino acids, peptides and proteins to radicals in the presence of O2 generates hydroperoxides in a dose-dependent manner. These hydroperoxides are stable in the absence of exogenous catalysts (e.g. heat, light, redox-active transition metal ions), but decompose rapidly in the presence...

  12. Progress Toward an Enceladus Amino Acid Sampler Astrobiology Instrument

    Science.gov (United States)

    Kirby, J. P.; Willis, P. A.; Blacksberg, J.

    2012-12-01

    The development of a new astrobiolgoy instrument for exploring the trace chemical composition of the Enceladus jets and plume, and the e-ring of Saturn is presented. The Enceladus amino acid sampler (EAAS) allows for detection of amino acids using optical Raman spectroscopy integrated with a sample pre-concentration system. The pre-concentration process facilitates the delivery of a sample to a mass spectrometer for detection of specific amino acids. The initial EAAS design utilizes lab-on-a-breadboard components where a sample inlet, sample outlet, reagents, controllers, pumps, valves and pre-concentration column for the EAAS prototype are all assembled on a 5" x 7" breadboard. The pre-concentration process is controlled using automation scripts and software. An optical window allows a Raman spectrometer to directly monitor the pre-concentration of amino acids in a filter/column loaded with of a strong cation exchange resin. Initial samples to demonstrate EAAS simulate the conditions of Don Juan Pond, one of the coldest and saltiest bodies of liquid water on Earth, located in the Wright Valley of Antarctica. This EAAS development is an important step toward a new type of astrobiology science instrument that is capable of operating on a spacecraft in flight or in orbit.

  13. Analysis of Saccharides by the Addition of Amino Acids

    Science.gov (United States)

    Ozdemir, Abdil; Lin, Jung-Lee; Gillig, Kent J.; Gulfen, Mustafa; Chen, Chung-Hsuan

    2016-06-01

    In this work, we present the detection sensitivity improvement of electrospray ionization (ESI) mass spectrometry of neutral saccharides in a positive ion mode by the addition of various amino acids. Saccharides of a broad molecular weight range were chosen as the model compounds in the present study. Saccharides provide strong noncovalent interactions with amino acids, and the complex formation enhances the signal intensity and simplifies the mass spectra of saccharides. Polysaccharides provide a polymer-like ESI spectrum with a basic subunit difference between multiply charged chains. The protonated spectra of saccharides are not well identified because of different charge state distributions produced by the same molecules. Depending on the solvent used and other ions or molecules present in the solution, noncovalent interactions with saccharides may occur. These interactions are affected by the addition of amino acids. Amino acids with polar side groups show a strong tendency to interact with saccharides. In particular, serine shows a high tendency to interact with saccharides and significantly improves the detection sensitivity of saccharide compounds.

  14. Identification of essential amino acids in the Streptococcus mutans glucosyltransferases.

    Science.gov (United States)

    Tsumori, H; Minami, T; Kuramitsu, H K

    1997-01-01

    A comparison of the amino acid sequences of the glucosyltransferases (GTFs) of mutans streptococci with those from the alpha-amylase family of enzymes revealed a number of conserved amino acid positions which have been implicated as essential in catalysis. Utilizing a site-directed mutagenesis approach with the GTF-I enzyme of Streptococcus mutans GS-5, we identified three of these conserved amino acid positions, Asp413, Trp491, and His561, as being important in enzymatic activity. Mutagenesis of Asp413 to Thr resulted in a GTF which expressed only about 12% of the wild-type activity. In contrast, mutagenesis of Asp411 did not inhibit enzyme activity. In addition, the D413T mutant was less stable than was the parental enzyme when expressed in Escherichia coli. Moreover, conversion of Trp491 or His561 to either Gly or Ala resulted in enzymes devoid of GTF activity, indicating the essential nature of these two amino acids for activity. Furthermore, mutagenesis of the four Tyr residues present at positions 169 to 172 which are part of a subdomain with homology to the direct repeating sequences present in the glucan-binding domain of the GTFs had little overall effect on enzymatic activity, although the glucan products appeared to be less adhesive. These results are discussed relative to the mechanisms of catalysis proposed for the GTFs and related enzymes. PMID:9171379

  15. Gas-Phase IR Spectroscopy of Deprotonated Amino Acids

    NARCIS (Netherlands)

    Oomens, J.; Steill, J. D.; Redlich, B.

    2009-01-01

    Gas-phase infrared multiple photon dissociation (IRMPD) spectra have been recorded for the conjugate bases of a series of amino acids (Asp, Cys, Glu, Phe, Set, Trp, Tyr). The spectra are dominated by strong symmetric and antisymmetric carboxylate stretching modes around 1300 and 1600 cm(-1), respect

  16. Engineering Dehydrated Amino Acid Residues in the Antimicrobial Peptide Nisin

    NARCIS (Netherlands)

    Kuipers, Oscar P.; Rollema, Harry S.; Yap, Wyanda M.G.J.; Boot, Hein J.; Siezen, Roland J.; Vos, Willem M. de

    1992-01-01

    The small antimicrobial peptide nisin, produced by Lactococcus lactis, contains the uncommon amino acid residues dehydroalanine and dehydrobutyrine and five thio ether bridges. Since these structures are posttranslationally formed from Ser, Thr, and Cys residues, it is feasible to study their role i

  17. CSF Amino Acids, Pterins and Mechanism of the Ketogenic Diet

    Directory of Open Access Journals (Sweden)

    J. Gordon Millichap

    2015-11-01

    Full Text Available Investigators from Hospital Sant Joan de Deu, Barcelona, Spain, studied the relationship between the etiology of refractory childhood epilepsy, CSF neurotransmitters, pterins, and amino acids, and response to a ketogenic diet in 60 patients with refractory epilepsy, 83% focal and 52% idiopathic.

  18. Amino acid salt solutions for carbon dioxide capture

    NARCIS (Netherlands)

    Majchrowicz, Magdalena Elzbieta

    2014-01-01

    Reactive absorption is a common process in the chemical industry and is used, among others, in the treatment of CO2 containing industrial gas streams. The current work was a part of a project with the aim to assess new reactive solvents based on amino acid salts for CO2 removal from industrial gas s

  19. Chiroptical Properties of Amino Acids: A Density Functional Theory Study

    Directory of Open Access Journals (Sweden)

    Martine Adrian-Scotto

    2010-04-01

    Full Text Available Amino acids are involved in many scientific theories elucidating possible origins of life on Earth. One of the challenges when discussing the evolutionary origin of biopolymers such as proteins and oligonucleotides in living organisms is the phenomenon that these polymers implement monomers of exclusively one handedness, a feature called biomolecular homochirality. Many attempts have been made to understand this process of racemic symmetry breaking. Assuming an extraterrestrial origin of the molecular building blocks of living organisms, their susceptibility to asymmetric photolysis by the absorption of circularly polarized electromagnetic radiation in interstellar space was proposed. In order to predict whether the interaction of circularly polarized light with various racemic amino acids can induce an enantiomeric excess, we investigated the electronic and chiroptical properties of the amino acids valine and isovaline by a molecular modelling approach based on quantum chemistry (Density Functional Theory. The average spectra of both L-valine and L-isovaline have been produced on the basis of Boltzmann population analysis using computed spectra for the various conformations of each amino acid.

  20. On the evolution of the standard amino-acid alphabet

    OpenAIRE

    Lu, Yi; Freeland, Stephen

    2006-01-01

    Although one standard amino-acid 'alphabet' is used by most organisms on Earth, the evolutionary cause(s) and significance of this alphabet remain elusive. Fresh insights into the origin of the alphabet are now emerging from disciplines as diverse as astrobiology, biochemical engineering and bioinformatics.

  1. One-Pot Synthesis of N-Phosphoryl Amino Acids

    Institute of Scientific and Technical Information of China (English)

    GUO Xin; FU Hua; LIN Chang-Xue; ZHAO Yu-Fen

    2003-01-01

    @@ Phosphoramidates have been considered as an important class of rationally designed therapeutics especially asoligonucleotide analogs employed as antisene and antigene agents. [1] N-Phosphoryl amino acids are of biological andpharmaceutical interest, [2] and can be used as the building blocks in synthesis of polypeptides. [3

  2. Single amino acid supplementation in aminoacidopathies : a systematic review

    NARCIS (Netherlands)

    van Vliet, Danique; Derks, Terry G. J.; van Rijn, Margreet; de Groot, Martijn J.; MacDonald, Anita; Heiner-Fokkema, M. Rebecca; van Spronsen, Francjan J.

    2014-01-01

    Aminoacidopathies are a group of rare and diverse disorders, caused by the deficiency of an enzyme or transporter involved in amino acid metabolism. For most aminoacidopathies, dietary management is the mainstay of treatment. Such treatment includes severe natural protein restriction, combined with

  3. Third generation capture system: precipitating amino acid solvent systems

    NARCIS (Netherlands)

    Sanchez Fernandez, E.; Misiak, K.; Ham, L. van der; Goetheer, E.L.V.

    2013-01-01

    This work summarises the results of the design of novel separation processes for CO2 removal from flue gas based on precipitating amino acid solvents. The processes here described (DECAB, DECAB Plus and pH-swing) use a combination of enhanced CO2 absorption (based on the Le Chatelier’s principle) an

  4. Genetics Home Reference: aromatic l-amino acid decarboxylase deficiency

    Science.gov (United States)

    ... features of aromatic L-amino acid decarboxylase deficiency. Neurology. 2010 Jul 6;75(1):64-71. doi: ... WNL.0b013e3181e620ae. Epub 2010 May 26. Erratum in: Neurology. 2010 Aug 10;75(6):576. Dosage error ...

  5. Polarized Raman spectra and intensities of aliphatic amino acids

    Science.gov (United States)

    Himmler, Hans J.; Eysel, Hans H.

    1989-01-01

    Raman spectra of aliphatic α- L-amino acids, glycine, alanine, and valine were re-investigated both in aqueous solution and deuterium oxide solution. The spectra were taken of the zwitterionic and of the completely deprotonated form of the amino acids. Spectra of leucine and isoleucine were studied in water at the isoelectric point. Spectra were recorded both with parallel and perpendicular polarization and the isotropic and anisotropic scattering components were isolated. The integrated intensities of CH stretch, CC stretch and carboxylate bend vibrations are discussed. Linear relations between the number of CC and CH bonds and the total scattered intensity in the appropriate spectral regions are observed. The sum over the carboxylate modes shows characteristic intensities for the first three members of the aliphatic amino acids. An increase of isotropic scattering of ϱ co 2 near 510 cm -1 with increasing chain length of the amino acid (or with increasing concentration) is interpreted as the result of micelle formation.

  6. Formation mechanism of coamorphous drug−amino acid mixtures

    DEFF Research Database (Denmark)

    Jensen, Katrine Birgitte Tarp; Larsen, Flemming Hofmann; Cornett, Claus;

    2015-01-01

    Two coamorphous drug−amino acid systems, indomethacin−tryptophan (Ind−Trp) and furosemide−tryptophan Fur−Trp), were analyzed toward their ease of amorphization and mechanism of coamorphization during ball milling. The two mixtures were compared to the corresponding amorphization of the pure drug...

  7. Solid-phase route to Fmoc-protected cationic amino acid building blocks

    DEFF Research Database (Denmark)

    Clausen, Jacob Dahlqvist; Linderoth, Lars; Nielsen, Hanne Mørck;

    2012-01-01

    was developed. A versatile solid-phase protocol leading to selectively protected amino alcohol intermediates was followed by oxidation to yield the desired di- or polycationic amino acid building blocks in gram-scale amounts. The synthetic sequence comprises loading of (S)-1-(p-nosyl)aziridine-2-methanol onto......Diamino acids are commonly found in bioactive compounds, yet only few are commercially available as building blocks for solid-phase peptide synthesis. In the present work a convenient, inexpensive route to multiple-charged amino acid building blocks with varying degree of hydrophobicity...... blocks having an Fmoc/Boc protection scheme. This strategy facilitates incorporation of multiple positive charges into the building blocks provided that the corresponding partially protected di- or polyamines are available. An array of compounds covering a wide variety of ¿-aza substituted analogs...

  8. Murine protein H is comprised of 20 repeating units, 61 amino acids in length

    DEFF Research Database (Denmark)

    Kristensen, Torsten; Tack, B F

    1986-01-01

    A cDNA library constructed from size-selected (greater than 28 S) poly(A)+ RNA isolated from the livers of C57B10. WR mice was screened by using a 249-base-pair (bp) cDNA fragment encoding 83 amino acid residues of human protein H as a probe. Of 120,000 transformants screened, 30 hybridized......, 448 bp of 3'-untranslated sequence, and a polyadenylylated tail of undetermined length. Murine pre-protein H was deduced to consist of an 18-amino acid signal peptide and 1216 residues of H-protein sequence. Murine H was composed of 20 repetitive units, each about 61 amino acid residues in length...

  9. Adsorption and properties of aromatic amino acids on single-walled carbon nanotubes

    Science.gov (United States)

    Wang, Cuihong; Li, Shuang; Zhang, Ruiqin; Lin, Zijing

    2012-02-01

    We investigated the adsorption of three aromatic amino acids--phenylalanine, tyrosine, and tryptophan--on the sidewalls of a number of representative single-walled carbon nanotubes (SWNTs) using density-functional tight-binding calculations, complemented by an empirical dispersion correction. The armchair (n, n) SWNTs (n = 3-12) and zigzag (n, 0) SWNTs (n = 4-12) were thoroughly examined. We found that the most stable amino acid/SWNT complexes for different SWNTs have similar local structures, and that the distance between the amino acid and SWNT is about 3 Å. Owing to the π-π and H-π stacking interactions, the benzene and indole rings are not exactly parallel to the SWNTs but instead lie at a small angle. We also investigated the diameter and chirality dependences of binding energies and found that SWNT (5, 0) has an especially large binding energy that can be used for SWNT identification or selection.

  10. Amino acid peroxyl radicals. Formation and reaction with ascorbate

    International Nuclear Information System (INIS)

    Complete text of publication follows. Proteins are significant targets for partly reduced oxygen species in vivo. This results in random formation of radicals on the amino acid residues (AA·) of the protein, which in turn, in the presence of oxygen, can yield the corresponding peroxyl radicals (AAOO·). Both radical types can cause further biological damage. We studied the N-acetylamide derivatives of the amino acids glycine, alanine and proline as models of these residues in proteins. We generated the amino acid radicals specifically by reaction with hydroxyl radicals produced in solutions irradiated with 2 MeV electrons in the presence of N2O. In the absence of oxygen the amino acid radicals decayed with rate constants in the narrow range (0.9-1.3) x 109 M-1s-1, while in the presence of oxygen they were converted very rapidly to the corresponding peroxyl radicals with rate constants that vary between 6.3 x 108 and 5.5 x 109 M-1s-1, depending on the amino acid. The corresponding N-acetylated amino acids were also studied and showed similar behaviour but with slightly smaller rate constants. Antioxidants are able to repair tyrosyl and tryptophanyl radicals in various proteins in vitro. For ascorbate, the principal endogenous biological antioxidant, we have measured rate constants in the range 105-108 M-1s-1. The peroxyl radicals of all amino acids studied here were reduced by oxidizing ascorbate to the ascorbyl radical. The reaction was followed at 360 nm, where ascorbyl radical has an absorption coefficient of 3300 M-1cm-1, and the derived rate constants were all close to 107 M-1s-1. However, the spontaneous decay of peroxyl radicals is also fast and competes with the reaction with ascorbate. It is to be stressed that reaction of AAOO· and ascorbate gives rise to hydroperoxides (AAOOH) that are also reactive molecules. Our study suggests that reaction with protein radicals may be responsible for the ascorbate loss reported in organisms exposed to oxidative

  11. Preparation and Characterization of Amino Acids-Based Trimethoprim Salts

    Directory of Open Access Journals (Sweden)

    Afzal R. Mohammed

    2012-02-01

    Full Text Available Trimethoprim (TMP is a dihydrofolate reductase (DHFR inhibitor which prevents the conversion of dihydrofolic acid into tetrahydrofolic acid, resulting in the depletion of the latter and leading to bacterial death. Oral bioavailability of TMP is hindered by both its low solubility and low permeability. This study aims to prepare novel salts of TMP using anionic amino acids; aspartic and glutamic acid as counter ions in order to improve solubility and dissolution. TMP salts were prepared by lyophilisation and characterized using FT-IR spectroscopy, proton nuclear magnetic resonance (1HNMR, Differential Scanning Calorimetry (DSC and Thermogravimetric analysis (TGA. Both the amino acids formed salts with TMP in a 1:1 molar ratio and showed a 280 fold improvement in solubility. Investigation of the microbiological activity of the prepared salts against TMP sensitive Escherichia coli showed that the new salts not only retained antibacterial activity but also exhibited higher zone of inhibition which was attributed to improved physicochemical characters such as higher solubility and dissolution. The results are an important finding that could potentially impact on faster onset of antibacterial activity and reduced therapeutic dose when administered to patients. Studies are underway investigating the effect of ion-pairing TMP with amino acids on the permeability profile of the drug.

  12. An expanded set of amino acid analogs for the ribosomal translation of unnatural peptides.

    Directory of Open Access Journals (Sweden)

    Matthew C T Hartman

    Full Text Available BACKGROUND: The application of in vitro translation to the synthesis of unnatural peptides may allow the production of extremely large libraries of highly modified peptides, which are a potential source of lead compounds in the search for new pharmaceutical agents. The specificity of the translation apparatus, however, limits the diversity of unnatural amino acids that can be incorporated into peptides by ribosomal translation. We have previously shown that over 90 unnatural amino acids can be enzymatically loaded onto tRNA. METHODOLOGY/PRINCIPAL FINDINGS: We have now used a competition assay to assess the efficiency of tRNA-aminoacylation of these analogs. We have also used a series of peptide translation assays to measure the efficiency with which these analogs are incorporated into peptides. The translation apparatus tolerates most side chain derivatives, a few alpha,alpha disubstituted, N-methyl and alpha-hydroxy derivatives, but no beta-amino acids. We show that over 50 unnatural amino acids can be incorporated into peptides by ribosomal translation. Using a set of analogs that are efficiently charged and translated we were able to prepare individual peptides containing up to 13 different unnatural amino acids. CONCLUSIONS/SIGNIFICANCE: Our results demonstrate that a diverse array of unnatural building blocks can be translationally incorporated into peptides. These building blocks provide new opportunities for in vitro selections with highly modified drug-like peptides.

  13. Comparison of the frequency of functional SH3 domains with different limited sets of amino acids using mRNA display.

    Directory of Open Access Journals (Sweden)

    Junko Tanaka

    Full Text Available Although modern proteins consist of 20 different amino acids, it has been proposed that primordial proteins consisted of a small set of amino acids, and additional amino acids have gradually been recruited into the genetic code. This hypothesis has recently been supported by comparative genome sequence analysis, but no direct experimental approach has been reported. Here, we utilized a novel experimental approach to test a hypothesis that native-like globular proteins might be easily simplified by a set of putative primitive amino acids with retention of its structure and function than by a set of putative new amino acids. We performed in vitro selection of a functional SH3 domain as a model from partially randomized libraries with different sets of amino acids using mRNA display. Consequently, a library rich in putative primitive amino acids included a larger number of functional SH3 sequences than a library rich in putative new amino acids. Further, the functional SH3 sequences were enriched from the primitive library slightly earlier than from a randomized library with the full set of amino acids, while the function and structure of the selected SH3 proteins with the primitive alphabet were comparable with those from the 20 amino acid alphabet. Application of this approach to various combinations of codons in protein sequences may be useful not only for clarifying the precise order of the amino acid expansion in the early stages of protein evolution but also for efficiently creating novel functional proteins in the laboratory.

  14. Amino acid supplementation alters bone metabolism during simulated weightlessness

    Science.gov (United States)

    Zwart, S. R.; Davis-Street, J. E.; Paddon-Jones, D.; Ferrando, A. A.; Wolfe, R. R.; Smith, S. M.

    2005-01-01

    High-protein and acidogenic diets induce hypercalciuria. Foods or supplements with excess sulfur-containing amino acids increase endogenous sulfuric acid production and therefore have the potential to increase calcium excretion and alter bone metabolism. In this study, effects of an amino acid/carbohydrate supplement on bone resorption were examined during bed rest. Thirteen subjects were divided at random into two groups: a control group (Con, n = 6) and an amino acid-supplemented group (AA, n = 7) who consumed an extra 49.5 g essential amino acids and 90 g carbohydrate per day for 28 days. Urine was collected for n-telopeptide (NTX), deoxypyridinoline (DPD), calcium, and pH determinations. Bone mineral content was determined and potential renal acid load was calculated. Bone-specific alkaline phosphatase was measured in serum samples collected on day 1 (immediately before bed rest) and on day 28. Potential renal acid load was higher in the AA group than in the Con group during bed rest (P < 0.05). For all subjects, during bed rest urinary NTX and DPD concentrations were greater than pre-bed rest levels (P < 0.05). Urinary NTX and DPD tended to be higher in the AA group (P = 0.073 and P = 0.056, respectively). During bed rest, urinary calcium was greater than baseline levels (P < 0.05) in the AA group but not the Con group. Total bone mineral content was lower after bed rest than before bed rest in the AA group but not the Con group (P < 0.05). During bed rest, urinary pH decreased (P < 0.05), and it was lower in the AA group than the Con group. These data suggest that bone resorption increased, without changes in bone formation, in the AA group.

  15. Separation and identification of amino acids from lignite humic acids by thin layer chromatography

    Energy Technology Data Exchange (ETDEWEB)

    Damian, L.; Marutoiu, C.; Niac, G.

    1985-07-01

    Thin layer chromatography with and without temperature gradient was used to identify ten amino acids in the humic acid hydrolysate of Rovinari lignite, using cellulose and volcanic tuff as stationary phases. The acids found were L-leucine, isoleucine, phenylalanine, L-valine, tyrosine, proline, L-alanine, glutamic acid, threonine and L-lysine. 8 references.

  16. Quantitative amino acid profiling and stable isotopically labeled amino acid tracer enrichment used for in vivo human systemic and tissue kinetics measurements

    DEFF Research Database (Denmark)

    Bornø, Andreas; van Hall, Gerrit

    2014-01-01

    . The present study describes a new sensitive liquid chromatography tandem mass-spectrometry method quantifying 20 amino acids and their tracer(s) ([ring-(13)C6]/D5Phenylalanine) in human plasma and skeletal muscle specimens. Before analysis amino acids were extracted and purified via deprotonization...... curve correlations for amino acids were on average; r(2)=0.998. Interday accuracy for amino acids determined in spiked plasma was on average 97.3% and the coefficient of variation (CV) was 2.6%. The ([ring-(13)C6]/D5Phenylalanine) enrichment CV's for machine reproducibility in muscle tissue fluid......An important area within clinical functional metabolomics is in vivo amino acid metabolism and protein turnover measurements for which accurate amino acid concentrations and stable isotopically labeled amino acid enrichments are mandatory not the least when tissue metabolomics is determined...

  17. Amino acid quality indices of the leaves ofClerodendrum volubile

    Institute of Scientific and Technical Information of China (English)

    Ochuko Lucky Erukainure; Folashade Oluwayemisi Owolabi; Temiloluwa Adebola Adesioye; Deborah Olabisi Akinyele; Grace Ijeoma Okonrokwo

    2016-01-01

    Objective: To evaluate the amino acid profile and quality indices ofClerodendrumvolubile (C. volubile) leaves. Methods:Dried leaves ofC. volubile were blended, defatted and subjected to amino acid analysis using the technicon sequential multi-sample amino acid analyzer. The amino acid quality indices which covers for chemical score, essential amino acid index, nutritional index, true digestibility, protein digestibility corrected amino acid score, and digestible indispensable amino acid score were evaluated using standard formulas. Results: Amino acid analysis revealed glutamic acid to have the highest concentration, with cysteine having the least. Aspartic acid had the highest chemical score, this was followed by glycine, histidine and arginine, respectively. The least scores were observed in serine and methionine. Glutamic acid had the highest value for true digestibility and protein digestibility corrected amino acid score, with the least observed in cysteine. Digestible indispensable amino acid score evaluation showed histidine to have the highest value for infants (birth to 6 months), threonine for children (6 months to 3 years), while isoleucine was observed to have the highest value for older children, adolescents and adults. The essential amino acid index value was less than 4, while nutritional index value was less than 0.5. Conclusions:These results indicated the leaves ofC. volubile as a potential source of amino acids in the human diet as portrayed by its amino acids profile and qualities.

  18. Radiation protection with mesalamine (5-amino salicylic acid)

    International Nuclear Information System (INIS)

    Purpose: Radiation proctitis induced during the therapy of rectal and prostate cancers, and radiation injuries in general, are often the principal dose limiting factor limiting dose escalation for radiation therapy. Thus, there has been a continuous search for radioprotective agents, especially those that could selectively protect normal tissues, as opposed to the target cancer. 5-amino salicylic acid (5ASA) is in clinical use as Mesalamine for the local treatment of ulcerative proctitis. Inasmuch as other investigators have identified 5ASA as a free radical scavenger, we determined whether pretreatment with 5ASA could confer radiation protection. Materials and Methods: Adult male C57BL/6J mice obtained from Jackson Laboratories were employed for these studies. We determined LD50 for acute gastrointestinal death for young (≤ 10 weeks old, ≤ 25 gms body weight) and aged (≥ 1 year old, ≥ 35 gms body weight) animals exposed to single fractions (1 - 20 Gy) from three different radiation sources, Cs137, 270 KeV x-rays, and a 4 MeV linear accelerator. Experimental mice were pre- or post-treated with 5ASA in an acidified isotonic saline solution by oral, rectal, or intraperitoneal administration. Animals were housed, maintained by AAALAC standards and treated with antibiotics or acidified water post radiation exposure to control opportunistic infections. Animals were scored for death when moribund. Results: 5ASA was found to be radioprotective by oral, rectal or intraperitoneal administration when given 15 to 90 minutes prior to radiation exposure. Administration of drug following radiation exposure failed to confer radioprotection. We determined a dose effect for 5ASA with maximum tolerated dose of 200 mg/kg administered ip 30 minutes prior to 11 Gy whole body exposure. Dose modification and radioprotection by 5ASA were determined by LD50(6), LD50(30), or LD50(365). More recently, we determined that 5ASA conferred significant radioprotection to mice exposed to

  19. Abiotic racemization kinetics of amino acids in marine sediments.

    Directory of Open Access Journals (Sweden)

    Andrew D Steen

    Full Text Available The ratios of d- versus l-amino acids can be used to infer the sources and composition of sedimentary organic matter. Such inferences, however, rely on knowing the rates at which amino acids in sedimentary organic matter racemize abiotically between the d- and the l-forms. Based on a heating experiment, we report kinetic parameters for racemization of aspartic acid, glutamic acid, serine, and alanine in bulk sediment from Aarhus Bay, Denmark, taken from the surface, 30 cm, and 340 cm depth below seafloor. Extrapolation to a typical cold deep sea sediment temperature of 3°C suggests racemization rate constants of 0.50×10(-5-11×10(-5 yr(-1. These results can be used in conjunction with measurements of sediment age to predict the ratio of d:l amino acids due solely to abiotic racemization of the source material, deviations from which can indicate the abundance and turnover of active microbial populations.

  20. Tuning hardness in calcite by incorporation of amino acids

    Science.gov (United States)

    Kim, Yi-Yeoun; Carloni, Joseph D.; Demarchi, Beatrice; Sparks, David; Reid, David G.; Kunitake, Miki E.; Tang, Chiu C.; Duer, Melinda J.; Freeman, Colin L.; Pokroy, Boaz; Penkman, Kirsty; Harding, John H.; Estroff, Lara A.; Baker, Shefford P.; Meldrum, Fiona C.

    2016-08-01

    Structural biominerals are inorganic/organic composites that exhibit remarkable mechanical properties. However, the structure-property relationships of even the simplest building unit--mineral single crystals containing embedded macromolecules--remain poorly understood. Here, by means of a model biomineral made from calcite single crystals containing glycine (0-7 mol%) or aspartic acid (0-4 mol%), we elucidate the origin of the superior hardness of biogenic calcite. We analysed lattice distortions in these model crystals by using X-ray diffraction and molecular dynamics simulations, and by means of solid-state nuclear magnetic resonance show that the amino acids are incorporated as individual molecules. We also demonstrate that nanoindentation hardness increased with amino acid content, reaching values equivalent to their biogenic counterparts. A dislocation pinning model reveals that the enhanced hardness is determined by the force required to cut covalent bonds in the molecules.

  1. Extraction Behavior and Wastewater Treatment of Amino Sulfonic Acid with Alamine 336

    Institute of Scientific and Technical Information of China (English)

    秦炜; 李振宇; 汪敏; 戴猷元

    2004-01-01

    p-Amino benzene sulfonic acid (PABSA) is selected as the solute with amphoteric functional group, Lewis acid and Lewis base, to be separated from its dilute solutions. An aliphatic, straight chain amine, Alamine 336, is used as the extractant, and kerosene, 1-octanol, chloroform, butyl acetate and benzene as the diluent. The effects of pH value of solution, extractant concentration, salt and types of diluent on the distribution coefficient, D, are studied. There is a peak of D value with pH value of solution, the polar diluents are favorable for extracting PABSA, and the salt in aqueous phase reduces values of D apparently. The extraction equilibrium is described using the mass action law, and the calculated data according to the proposed model agree with the experimental data well. Further, the extraction behavior for other amino benzene sulfonic acids, 1-amino-8-naphtol-3,6-disulfonic acid (H acid) and 4,4′-diaminostilbene-2,2′-disulfonic acid (DSD acid), is investigated in a wide pH value region. Finally. H acid and DSD acid are successfully removed from wastewater by the extraction with Alamine 336.

  2. Reactions of Hot Tritiúm Atoms with Amino Acids

    International Nuclear Information System (INIS)

    In the existing literature there is a lack of systematic data on the interaction of tritium recoil atoms with amino acids, yet such data, in conjunction with results already obtained for organic acids and amines, could help in determining the mechanism of hot reactions in relation to the structure of compounds (chain length, functional substitutes). A study was made of the yields from the reaction of hot tritium atoms: (1) with amino acids having lengthened chains, and (2) with amino acids having a carbon chain of constant length, but with various functional substitutes. For this purpose mixtures of lithium carbonate and the acids under study were irradiated for 15 min with a slow neutron flux of 0.87 x 1013 cm2/s. Analysis was carried out on a gas chromatography unit with interchangeable columns (molecular sieves, and liquid petrolatum on kieselguhr) and with paper chromatography. Although the data obtained for the radiation survival capacity of amino acids as a function of carbon chain length were at variance with a basic tenet of radiation chemistry according to which the conservation of molecules increases in proportion to the length of their chains, the data can be explained in terms of an intramolecular transfer of energy along the carbon chain from the collision site of the hot atom to the hydroxyl group, and subsequent ''de-excitation''; on the other hand, although the energy, of tritium recoil atoms is greater than that of the chemical bond, the latter nevertheless exerts an influence on the radiation conservation of molecules with a carbon chain of constant length but with various substitutes. (author)

  3. Studies of 3-amino-4-hydroxyl benzoic acid phosphate

    International Nuclear Information System (INIS)

    3-amino-4-hydroxyl benzoic acid phosphate was synthesized from 4-chloro benzoic acid through three steps, the whole process was cost-effective in which the materials in each step were reused. More importantly, phosphoric acid medium did no harm to Pd-C catalyst in the hydrogenation and the Pd-C catalyst could be recycled for ten times at least without decrease in catalytic activity. In addition, product could meet the requirement of polymerization reaction of producing poly(2,5-benzoxazole) without dehydrochlorogenation. In this process, good conversion, high overall yield (79.28%) and high purity (99.30% by HPLC) were achieved. (author)

  4. Probing the Specificity Determinants of Amino Acid Recognition by Arginase

    Energy Technology Data Exchange (ETDEWEB)

    Shishova, E.; Di Costanzo, L; Emig, F; Ash, D; Christianson, D

    2009-01-01

    Arginase is a binuclear manganese metalloenzyme that serves as a therapeutic target for the treatment of asthma, erectile dysfunction, and atherosclerosis. In order to better understand the molecular basis of inhibitor affinity, we have employed site-directed mutagenesis, enzyme kinetics, and X-ray crystallography to probe the molecular recognition of the amino acid moiety (i.e., the ?-amino and ?-carboxylate groups) of substrate l-arginine and inhibitors in the active site of arginase I. Specifically, we focus on (1) a water-mediated hydrogen bond between the substrate ?-carboxylate and T135, (2) a direct hydrogen bond between the substrate ?-carboxylate and N130, and (3) a direct charged hydrogen bond between the substrate ?-amino group and D183. Amino acid substitutions for T135, N130, and D183 generally compromise substrate affinity as reflected by increased KM values but have less pronounced effects on catalytic function as reflected by minimal variations of kcat. As with substrate KM values, inhibitor Kd values increase for binding to enzyme mutants and suggest that the relative contribution of intermolecular interactions to amino acid affinity in the arginase active site is water-mediated hydrogen bond < direct hydrogen bond < direct charged hydrogen bond. Structural comparisons of arginase with the related binuclear manganese metalloenzymes agmatinase and proclavaminic acid amidinohydrolase suggest that the evolution of substrate recognition in the arginase fold occurs by mutation of residues contained in specificity loops flanking the mouth of the active site (especially loops 4 and 5), thereby allowing diverse guanidinium substrates to be accommodated for catalysis.

  5. The Crystal Structure of the Adenylation Enzyme VinN Reveals a Unique β-Amino Acid Recognition Mechanism*

    Science.gov (United States)

    Miyanaga, Akimasa; Cieślak, Jolanta; Shinohara, Yuji; Kudo, Fumitaka; Eguchi, Tadashi

    2014-01-01

    Adenylation enzymes play important roles in the biosynthesis and degradation of primary and secondary metabolites. Mechanistic insights into the recognition of α-amino acid substrates have been obtained for α-amino acid adenylation enzymes. The Asp residue is invariant and is essential for the stabilization of the α-amino group of the substrate. In contrast, the β-amino acid recognition mechanism of adenylation enzymes is still unclear despite the importance of β-amino acid activation for the biosynthesis of various natural products. Herein, we report the crystal structure of the stand-alone adenylation enzyme VinN, which specifically activates (2S,3S)-3-methylaspartate (3-MeAsp) in vicenistatin biosynthesis. VinN has an overall structure similar to that of other adenylation enzymes. The structure of the complex with 3-MeAsp revealed that a conserved Asp230 residue is used in the recognition of the β-amino group of 3-MeAsp similar to α-amino acid adenylation enzymes. A mutational analysis and structural comparison with α-amino acid adenylation enzymes showed that the substrate-binding pocket of VinN has a unique architecture to accommodate 3-MeAsp as a β-amino acid substrate. Thus, the VinN structure allows the first visualization of the interaction of an adenylation enzyme with a β-amino acid and provides new mechanistic insights into the selective recognition of β-amino acids in this family of enzymes. PMID:25246523

  6. The crystal structure of the adenylation enzyme VinN reveals a unique β-amino acid recognition mechanism.

    Science.gov (United States)

    Miyanaga, Akimasa; Cieślak, Jolanta; Shinohara, Yuji; Kudo, Fumitaka; Eguchi, Tadashi

    2014-11-01

    Adenylation enzymes play important roles in the biosynthesis and degradation of primary and secondary metabolites. Mechanistic insights into the recognition of α-amino acid substrates have been obtained for α-amino acid adenylation enzymes. The Asp residue is invariant and is essential for the stabilization of the α-amino group of the substrate. In contrast, the β-amino acid recognition mechanism of adenylation enzymes is still unclear despite the importance of β-amino acid activation for the biosynthesis of various natural products. Herein, we report the crystal structure of the stand-alone adenylation enzyme VinN, which specifically activates (2S,3S)-3-methylaspartate (3-MeAsp) in vicenistatin biosynthesis. VinN has an overall structure similar to that of other adenylation enzymes. The structure of the complex with 3-MeAsp revealed that a conserved Asp(230) residue is used in the recognition of the β-amino group of 3-MeAsp similar to α-amino acid adenylation enzymes. A mutational analysis and structural comparison with α-amino acid adenylation enzymes showed that the substrate-binding pocket of VinN has a unique architecture to accommodate 3-MeAsp as a β-amino acid substrate. Thus, the VinN structure allows the first visualization of the interaction of an adenylation enzyme with a β-amino acid and provides new mechanistic insights into the selective recognition of β-amino acids in this family of enzymes. PMID:25246523

  7. Amino acids attached to 2'-amino-LNA: Synthesis of DNA mixmer oligonucleotides with increased duplex stability

    DEFF Research Database (Denmark)

    Johannsen, Marie Willaing; Wengel, Jesper; Wamberg, Michael Chr.;

    2010-01-01

    The synthesis of 2'-amino-LNA (locked nucleic acid) opens up exciting possibilities for modification of nucleic acids by conjugation to the 2'-nitrogen. Incorporation of unmodified and N-functionalized 2'-amino-LNA nucleotides improve duplex stability compared to unmodified DNA. 2'-Amino......-LNA nucleosides derivatized with amino acids have been synthesized and incorporated into DNA oligonucleotides. Following oligonucleotide synthesis, peptides have been added using solid phase peptide coupling chem. Modification of oligonucleotides with pos. charged residues greatly improves thermal stability....

  8. The cysteine, total sulfur amino acid, tyrosine, phenylalanine + tyrosine, and non-essential amino acid maintenance requirements of broiler breeders.

    Science.gov (United States)

    Ekmay, R D; Mei, S J; Sakomura, N K; Coon, C N

    2016-06-01

    Two hundred and fifty Cobb-Vantress broiler breeders were used to determine the maintenance requirement and efficiency of utilization of dietary Cys, Tyr, and non-essential amino acids (AA) in a 21-day experiment. The breeders were fed crystalline amino acid diets containing graded levels of Cys or Tyr representing 0, 10, 20, 30, and 40% of their suggested requirement level with all other amino acids maintained at 40% of their suggested requirement level. To determine the non-essential AA maintenance requirement, graded levels of non-essential AA were provided by glutamic acid to represent 12, 19, 26, 33, and 40% of the ideal level of glutamic acid with all other amino acids maintained at their maintenance requirement level. The total sulfur amino acid (TSAA) and Phe + Tyr requirements were calculated by combining Cys and Tyr results, respectively, with previously determined Met and Phe, respectively. The slope of Cys, Tyr, and non-essential AA accretion regression line indicated that 29% Cys, 24% TSAA, 21% Tyr, 20% Phe + Tyr, and 9% non-essential AA of crystalline amino acids were retained. The Cys requirement for zero protein accretion was calculated to be 30.48 mg/d or 17.006 mg/ kgBW(0.75)/d or 75.426 mg/kgCP/d. The TSAA requirement for zero accretion was calculated to be 132.25 mg/b/d, 71.48 mg/kgBW(0.75)/d, and 307.55 mg/kgCP/d. The Tyr requirement for zero protein accretion was calculated to be 65.907 mg/d or 37.233 mg/ kgBW(0.75)/d or 175.566 mg/kgCP/d. The Phe + Tyr requirement for zero protein accretion was calculated to be 352.18 mg/b/d, 190.37 mg/kgBW(0.75)/d, and 749.33 mg/kgCP/d. The non-essential AA requirement for zero protein accretion was calculated to be 3715.194 mg/d or 2003.155 mg/kgBW(0.75)/d or 9452.954 mg/kgCP/d.

  9. Photo-CIDNP studies of amino acids and proteins

    Energy Technology Data Exchange (ETDEWEB)

    Lopez, J.J

    2001-07-01

    The ultimate aim of the research described in this thesis is the development of methods with which ope may study the structure and function of proteins on a molecular level. This is done with the help of a combination of NMR (Nuclear Magnetic Resonance) and flash photolysis, in which light initiated reactions between a chromophore and an amino acid induce abnormal NMR intensities. Chapters 1, 2 and 3: In the first chapter, a brief introduction of CIDNP and its application to proteins is given, followed by a short description of each chapter. The second chapter is an introductory review, covering the basics of the NMR experiment in the first part, and the theory behind the CIDNP phenomenon in the second. Chapter three describes the experimental apparatus and methods. Chapter 4: Photosensitization The light initiated chemical reaction between photosensitizer and amino acid residue is studied in detail for the case of FMN (flavinmononucleotide) and the amino acids tyrosine, tryptophan and histidine. An introduction is given of further sensitizers which have been found to generate CIDNP on amino acids, and which are used in later chapters. Chapter 5: CIDNP of Amino Acids and Proteins The typical CIDNP spectra of the amino acids tyrosine, tryptophan and histidine are introduced and elucidated in the first half of this chapter. Photo-CIDNP on the proteins ribonuclease A and Hen Egg White Lysozyme with the photosensitizers FMN, thionin and eosin Y are described in the second half. Chapter 6: CIDNP in Micellar Solutions The presence of detergent, below and above the critical micelle concentration, is shown to affect CIDNP intensities, due to electrostatic interactions between charged dye and detergent molecules. In the last part of this chapter, photo-CIDNP experiments with the membrane protein gramicidin A, incorporated in detergent and lipid micelles, are described. Chapter 7: CIDNP Study of the Tryptophan Radical CIDNP spectra are characteristic of the transient radical

  10. LC/ESI-MS analysis of underivatized amino acids and mass spectrum

    CERN Document Server

    Takano, Yoshinori; Ohkouchi, Naohiko

    2016-01-01

    We report the method of LC/ESI-MS analysis of underivatized amino acids with corresponding mass spectrum and fragmentation patterns. Diagnostic product ions determined by mass spectrometry can support the qualitative identification and quantitative estimation of individual amino acids. Therefore, the optimization of chromatographic separation using the ion-pairing reagent (i.e., Nonafluoropentanoic acid, NFPA) is useful for the evaluation of target amino acid and for further compound-specific nitrogen isotope studies of amino acids.

  11. Branched-chain amino acid supplementation during bed rest: effect on recovery

    Science.gov (United States)

    Stein, T. P.; Donaldson, M. R.; Leskiw, M. J.; Schluter, M. D.; Baggett, D. W.; Boden, G.

    2003-01-01

    Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced (P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

  12. Generation of deviation parameters for amino acid singlets, doublets and triplets from three-dimensional structures of proteins and its implications for secondary structure prediction from amino acid sequences

    Indian Academy of Sciences (India)

    S A Mugilan; K Veluraja

    2000-03-01

    We present a new method, secondary structure prediction by deviation parameter (SSPDP) for predicting the secondary structure of proteins from amino acid sequence. Deviation parameters (DP) for amino acid singlets, doublets and triplets were computed with respect to secondary structural elements of proteins based on the dictionary of secondary structure prediction (DSSP)-generated secondary structure for 408 selected non-homologous proteins. To the amino acid triplets which are not found in the selected dataset, a DP value of zero is assigned with respect to the secondary structural elements of proteins. The total number of parameters generated is 15,432, in the possible parameters of 25,260. Deviation parameter is complete with respect to amino acid singlets, doublets, and partially complete with respect to amino acid triplets. These generated parameters were used to predict secondary structural elements from amino acid sequence. The secondary structure predicted by our method (SSPDP) was compared with that of single sequence (NNPREDICT) and multiple sequence (PHD) methods. The average value of the percentage of prediction accuracy for α-helix by SSPDP, NNPREDICT and PHD methods was found to be 57%, 44% and 69% respectively for the proteins in the selected dataset. For -strand the prediction accuracy is found to be 69%, 21% and 53% respectively by SSPDP, NNPREDICT and PHD methods. This clearly indicates that the secondary structure prediction by our method is as good as PHD method but much better than NNPREDICT method.

  13. (Amino acid + silica) adsorption thermodynamics: Effects of temperature

    International Nuclear Information System (INIS)

    Highlights: • High resolution, low concentration Gly, Lys and Glu solution adsorption isotherms. • All isotherms fitted with Langmuir–Freundlich isotherm model. • Gly, Lys and Glu show exothermic adsorption processes. • Isosteric heat analyses reveal changes in interaction strength with surface coverage. - Abstract: A thorough understanding of amino acid adsorption by mineral and oxide surfaces has a major impact on a variety of industrial and biomedical applications. Little information currently exists regarding temperature effects on most of these adsorption processes. Deeper thermodynamic analyses of their multiple temperature adsorption isotherms would aid the interpretation of the interfacial interactions. Low solution concentration adsorption isotherms for glycine, lysine and glutamic acid on a silica adsorbent were generated for T = (291, 298 and 310) K. Data analysis via the Clausius–Clapeyron method yielded the isosteric heat of adsorption as a function of fractional monolayer coverage for each adsorptive. Each amino acid showed an exothermic adsorption response. Glycine and lysine experienced a greater negative effect of increased temperature compared with glutamic acid, indicating a greater number of adsorbed molecules than glutamic acid, with the former undergoing intermolecular clustering within the adsorbed phase. Isosteric heat analyses suggest ionic interactions for lysine and hydrogen bonding for glutamic acid, both weakening with increased coverage. In contrast, initial hydrogen bonding led to ionic bonding for glycine with increasing coverage

  14. INTERACTION OF AMINO ACID WITH ION EXCHANGE RESIN Ⅲ.FURTHER INVESTIGA TION OF SUPEREQUIVALENT ADSORPTION MECHANISM OF AMINO ACID ON ION EXCHANGE RESIN

    Institute of Scientific and Technical Information of China (English)

    ZHANGHui; SHAOTong; 等

    1994-01-01

    The adsorption isotherms of glycine,alanine and oxidized glutathion on strong acid cation and strong base anion exchange resins from aqueous solutions were measured and the superequivalent adsorptions of glycine and alanine observed.The infrared spectra of glycine adsorbed on the cation and the anion exchange resins,001×7 and 201×7,were measured.From these results,it is concluded that the amino acid adsorption on the ion exchange resin proceeds not only through ion exchange and proton transfer mechanisms,but also through aminecarboxylate interaction between the adsorbed amino acid molecules,and the formation of second layer of amino acid molecules is the mechanism of superequivalent adsorption of amino acid,the carboxylate or amine groups of the first layer of amino acid molecules on the ion exchange resin act as the exchange sites for the second layer of amino acid molecules.

  15. Topological features of proteins from amino acid residue networks

    CERN Document Server

    Alves, N A; Alves, Nelson Augusto; Martinez, Alexandre Souto

    2006-01-01

    Topological properties of native folds are obtained from statistical analysis of 160 low homology proteins covering the four structural classes. This is done analysing one, two and three-vertex joint distribution of quantities related to the corresponding network of amino acid residues. Emphasis on the amino acid residue hydrophobicity leads to the definition of their center of mass as vertices in this contact network model with interactions represented by edges. The network analysis helps us to interpret experimental results such as hydrophobic scales and fraction of buried accessible surface area in terms of the network connectivity. To explore the vertex type dependent correlations, we build a network of hydrophobic and polar vertices. This procedure presents the wiring diagram of the topological structure of globular proteins leading to the following attachment probabilities between hydrophobic-hydrophobic 0.424(5), hydrophobic-polar 0.419(2) and polar-polar 0.157(3) residues.

  16. Informational Way to Protein Alphabet: Entropic Classification of Amino Acids

    CERN Document Server

    Gorban, A N; Popova, T

    2007-01-01

    What are proteins made from, as the working parts of the living cells protein machines? To answer this question, we need a technology to disassemble proteins onto elementary func-tional details and to prepare lumped description of such details. This lumped description might have a multiple material realization (in amino acids). Our hypothesis is that informational approach to this problem is possible. We propose a way of hierarchical classification that makes the primary structure of protein maximally non-random. The first steps of the suggested research program are realized: the method and the analysis of optimal informational protein binary alphabet. The general method is used to answer several specific questions, for example: (i) Is there a syntactic difference between Globular and Membrane proteins? (ii) Are proteins random sequences of amino acids (a long discussion)? For these questions, the answers are as follows: (i) There exists significant syntactic difference between Globular and Membrane proteins,...

  17. Amino Acids Catalyzed Direct Aldol Reactions in Aqueous Micelles

    Institute of Scientific and Technical Information of China (English)

    PENG Yi-Yuan; WANG Qi; DING Qiu-Ping; HE Jia-Qi; CHENG Jin-Pei

    2003-01-01

    @@ Since the discovery of its roles as a good small-organic-molecule catalyst in intramolecular aldol reactions, pro line has drawn considerable attention in synthetic chemistry due to its similarity to the type-Ⅰ aldolases. Recently,List and others have reported some new direct asymmetric intermolecular reactions catalyzed by proline, including aldol, Mannich, Michael, and other analogous reactions. Except for two recent examples, [1,2] proline catalyzed aldol reactions in aqueous micelles have not been reported, nor have other amino acids as organocatalysts in directly catalyzing aldol reaction been reported. Herein we wish to present our recent results regarding environmentally be nign direct aldol reactions catalyzed by amino acids including proline, histidine and arginine in aqueous media.

  18. Energy Absorption and Exposure Buildup Factors of Essential Amino Acids

    Directory of Open Access Journals (Sweden)

    Ertuğrul Bursalıoğlu

    2014-01-01

    Full Text Available The effective atomic number and effective electron density in amino acids are of significant interest due to their use in various applications. The energy absorption buildup factors, exposure buildup factors, effective atomic numbers, and electron densities of essential amino acids such as Leucine (C6H13NO2, Lysine (C6H14N2O2, Methionine (C5H11NO2S, Phenylalanine (C9H11NO2, Threonine (C4H9NO3, Tryptophan (C11H12N2O2, Valine (C5H11NO2, Arginine (C6H14N4O2, and Histidine (C6H9N3O2 were determined theoretically in the energy range 0.015–15 MeV.

  19. Recent advances in amino acid analysis by capillary electrophoresis.

    Science.gov (United States)

    Poinsot, Véréna; Carpéné, Marie-Anne; Bouajila, Jalloul; Gavard, Pierre; Feurer, Bernard; Couderc, François

    2012-01-01

    This paper describes the most important articles that have been published on amino acid analysis using CE during the period from June 2009 to May 2011 and follows the format of the previous articles of Smith (Electrophoresis 1999, 20, 3078-3083), Prata et al. (Electrophoresis 2001, 22, 4129-4138) and Poinsot et al. (Electrophoresis 2003, 24, 4047-4062; Electrophoresis 2006, 27, 176-194; Electrophoresis 2008, 29, 207-223; Electrophoresis 2010, 31, 105-121). We present new developments in amino acid analysis with CE, which are reported describing the use of lasers or light emitting diodes for fluorescence detection, conductimetry electrochemiluminescence detectors, mass spectrometry applications, and lab-on-a-chip applications using CE. In addition, we describe articles concerning clinical studies and neurochemical applications of these techniques.

  20. Correlation between fibroin amino acid sequence and physical silk properties.

    Science.gov (United States)

    Fedic, Robert; Zurovec, Michal; Sehnal, Frantisek

    2003-09-12

    The fiber properties of lepidopteran silk depend on the amino acid repeats that interact during H-fibroin polymerization. The aim of our research was to relate repeat composition to insect biology and fiber strength. Representative regions of the H-fibroin genes were sequenced and analyzed in three pyralid species: wax moth (Galleria mellonella), European flour moth (Ephestia kuehniella), and Indian meal moth (Plodia interpunctella). The amino acid repeats are species-specific, evidently a diversification of an ancestral region of 43 residues, and include three types of regularly dispersed motifs: modifications of GSSAASAA sequence, stretches of tripeptides GXZ where X and Z represent bulky residues, and sequences similar to PVIVIEE. No concatenations of GX dipeptide or alanine, which are typical for Bombyx silkworms and Antheraea silk moths, respectively, were found. Despite different repeat structure, the silks of G. mellonella and E. kuehniella exhibit similar tensile strength as the Bombyx and Antheraea silks. We suggest that in these latter two species, variations in the repeat length obstruct repeat alignment, but sufficiently long stretches of iterated residues get superposed to interact. In the pyralid H-fibroins, interactions of the widely separated and diverse motifs depend on the precision of repeat matching; silk is strong in G. mellonella and E. kuehniella, with 2-3 types of long homogeneous repeats, and nearly 10 times weaker in P. interpunctella, with seven types of shorter erratic repeats. The high proportion of large amino acids in the H-fibroin of pyralids has probably evolved in connection with the spinning habit of caterpillars that live in protective silk tubes and spin continuously, enlarging the tubes on one end and partly devouring the other one. The silk serves as a depot of energetically rich and essential amino acids that may be scarce in the diet. PMID:12816957

  1. Chiroptical Properties of Amino Acids: A Density Functional Theory Study

    OpenAIRE

    Martine Adrian-Scotto; Serge Antonczak; Jan Hendrik Bredehöft; Hoffmann, Søren V.; Meierhenrich, Uwe J.

    2010-01-01

    Amino acids are involved in many scientific theories elucidating possible origins of life on Earth. One of the challenges when discussing the evolutionary origin of biopolymers such as proteins and oligonucleotides in living organisms is the phenomenon that these polymers implement monomers of exclusively one handedness, a feature called biomolecular homochirality. Many attempts have been made to understand this process of racemic symmetry breaking. Assuming an extraterrestrial origin of the ...

  2. Evaluation of Physiological Amino Acids Profiling by Tandem Mass Spectrometry

    OpenAIRE

    Filee, Romain; Schoos, Roland; Boemer, François

    2013-01-01

    Background: Nowadays, the most conventional method to quantify physiological amino acids consists in ion exchange chromatography (IEC) followed by post-column ninhydrin derivatization and UV detection at two wavelengths. Unfortunately, the technique presents some drawbacks such as long run time, large sample volume, and specific costs associated to the maintenance of a dedicated instrument. Therefore, we aimed to switch towards a mass spectrometry approach.

  3. Amino acid-sensing ion channels in plants

    Energy Technology Data Exchange (ETDEWEB)

    Spalding, Edgar P.

    2014-08-12

    The title of our project is “Amino acid-sensing ion channels in plants”. Its goals are two-fold: to determine the molecular functions of glutamate receptor-like (GLR) proteins, and to elucidate their biological roles (physiological or developmental) in plants. Here is our final technical report. We were highly successful in two of the three aims, modestly successful in the third.

  4. Addicting diverse bacteria to a noncanonical amino acid.

    Science.gov (United States)

    Tack, Drew S; Ellefson, Jared W; Thyer, Ross; Wang, Bo; Gollihar, Jimmy; Forster, Matthew T; Ellington, Andrew D

    2016-03-01

    Engineered orthogonal translation systems have greatly enabled the expansion of the genetic code using noncanonical amino acids (NCAAs). However, the impact of NCAAs on organismal evolution remains unclear, in part because it is difficult to force the adoption of new genetic codes in organisms. By reengineering TEM-1 β-lactamase to be dependent on a NCAA, we maintained bacterial NCAA dependence for hundreds of generations without escape. PMID:26780407

  5. Dynamics of human whole body amino acid metabolism

    International Nuclear Information System (INIS)

    The mechanism of regulation of the nitrogen metabolism in humans under various nutritional and physiological states was examined using stable isotopes. In the simultaneous continuous infusion of 1- [13] - leucine and α- [15N]- lysine, their fluxed decreased when individuals received lower protein intake. The rates of oxidation and incorporation into body proteins of leucine changed in parallel with the protein intake. Such effects of diet on whole body leucine kinetics were modified by the energy state and dietary energy level. The nitrogen balance was also improved by an excess level of dietary energy. When the intake of dietary protein was lowered below the maintenance level, the whole body flux and de novo synthesis of glycine were lowered, but alanine synthesis was clearly increased. The intravenous infusion of glucose at 4 mg/kg.min, which causes increase in excess blood sugar and plasma insulin, increased the alanine flux, but had no effect on the glycine flux. The rate of albumin synthesis, determined by giving 15N-glycine orally every 3 hr, decreased with the lowered intake of dietary protein in young men, but not in elderly men. This explains why the serum albumin synthesis increases with the increase in the intake of dietary protein in young men, but not in elderly men. The rate of whole body protein synthesis in young men receiving the L-amino acid diets providing with the required intake of specific amino acid was much lower than that in the men receiving the diets providing with generous intake of specific amino acid. Thus the control mechanism to maintain the homeostasis of body nitrogen and amino acids is related in some unknown way to the nutritional requirement of the hosts. (Kaihara, S.)

  6. Excitatory amino acid transporters as potential drug targets

    DEFF Research Database (Denmark)

    Bunch, Lennart; Erichsen, Mette Navy; Jensen, Anders Asbjørn

    2009-01-01

    BACKGROUND: Excitatory amino acid transporters (EAATs) are transmembrane proteins responsible for the uptake of (S)-glutamate (Glu) from the synaptic cleft, thereby terminating the glutamatergic neurotransmitter signal. Today five subtypes have been identified. Except for EAAT2, their individual...... and detailed understanding of EAATs be obtained. Thus we encourage collaboration between organic chemists and molecular pharmacologists, who, together, may pave the way for new EAAT ligands of importance....

  7. Direct amidation of amino acid derivatives catalyzed by arylboronic acids : applications in dipeptide synthesis.

    OpenAIRE

    Liu, S.; Yang, Y.; Liu, X.; Ferdousi, F. K.; Batsanov, A.S.; Whiting, A

    2013-01-01

    The direct amidation of amino acid derivatives catalyzed by arylboronic acids has been examined. The reaction was generally slow relative to simple amine-carboxylic acid combinations though proceeded at 65–68 °C generally avoiding racemization. 3,4,5-Trifluorophenylboronic and o-nitrophenylboronic acids were found to be the best catalysts, though for slower dipeptide formations, high catalyst loadings were required and an interesting synergistic catalytic effect between two arylboronic acids ...

  8. Synthesis of alkynes and alkynyl iodides bearing a protected amino alcohol moiety as functionalized amino acids precursors

    Institute of Scientific and Technical Information of China (English)

    AYED; Charfedinne; PICARD; Julien; LUBIN-GERMAIN; Nadège; UZIEL; Jacques; AUGE; Jacques

    2010-01-01

    Amino acid precursors in protected amino alcohol form are important synthons that can be used as building-blocks for the hemisynthesis of non-natural amino acids.Serine can be used as a common starting material for the synthesis of such compounds differently protected.Particularly,protected amino alcohols bearing an ethynyl and/or an iodoethynyl group can be used in cross-couplings,in 1,3-dipolar cycloadditions and/or in Nozaki-Hiyama-Kishi type reactions.We thus demonstrated that the efficiently protected amino alcohols derived from serine can be coupled to a sugar derivative by an indium mediated alkynylation reaction.The conditions of this coupling are compatible with such functionalized derivatives and allow envisaging an access to C-glycosylated amino acids.

  9. Hydration of protonated aromatic amino acids: phenylalanine, tryptophan, and tyrosine.

    Science.gov (United States)

    Gao, Bing; Wyttenbach, Thomas; Bowers, Michael T

    2009-04-01

    The first steps of hydration of the protonated aromatic amino acids phenylalanine, tryptophan, and tyrosine were studied experimentally employing a mass spectrometer equipped with a drift cell to examine the sequential addition of individual water molecules in equilibrium experiments and theoretically by a combination of molecular mechanics and electronic structure calculations (B3LYP/6-311++G**) on the three amino acid systems including up to five water molecules. It is found that both the ammonium and carboxyl groups offer good water binding sites with binding energies of the order of 13 kcal/mol for the first water molecule. Subsequent water molecules bind less strongly, in the range of 7-11 kcal/mol for the second through fifth water molecules. The ammonium group is able to host up to three water molecules and the carboxyl group one water molecule before additional water molecules bind either to the amino acid side chain as in tyrosine or to already-bound water in a second solvation shell around the ammonium group. Reasons for the surprisingly high water affinity of the neutral carboxyl group, comparable to that of the charge-carrying ammonium group, are found to be high intrinsic hydrophilicity, favorable charge-dipole alignment, and--for the case of multiply hydrated species--favorable dipole-dipole interaction among water molecules and the lack of alternative fully exposed hydration sites.

  10. Phase Chemistry of the Complexes of RE Amino Acids

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Forty-three phase diagrams of ternary system concerning rare earth salts, α-amino acids and water, which were constructed by phase equilibrium methods, were expounded. The influences of the factors such as cations, anions, the structure of amino acids, temperature on the phase diagrams were discussed. Under the guidance of phase equilibrium results, over 150 new solid complexes were prepared. IR, reflecting, UV, FS, and Raman spectra for these complexes were investigated and the regularity of “tripartite effect”, “tetrad effect”, “Nephelanxetic effect”, “Oddo-Harkins” was observed. Thermal decomposition processes of the complexes were confirmed. Based on the comparison with the known crystal structures of rare earth-amino acid-complexes, an estimation method for predicting the crystal structure data of series complexes was founded. The constant volume combustion energies of the complexes were determined by RBC-1 type rotating bomb calorimeter. The standard enthalpies of combustion and standard enthalpies of formation were calculated for these complexes.

  11. Metabolic regulation of amino acid uptake in marine waters

    Energy Technology Data Exchange (ETDEWEB)

    Kirchman, D.L.; Hodson, R.E.

    1986-03-01

    To determine the relationships among the processes of uptake, intracellular pool formation, and incorporation of amino acids into protein, the authors measured the uptake of dipeptides and free amino acids by bacterial assemblages in estuarine and coastal waters of the southeast US. The dipeptide phenylalanyl-phenylalanine (phe-phe) lowered V/sub max/ of phenylalanine uptake when the turnover rate of phenylalanine was relatively high. When the turnover rate was relatively low, phe-phe either had no effect or increased V/sub max/ of phenylalanine uptake. An analytical model was developed and tested to measure the turnover time of the intracellular pool of phenylalanine. The results suggested that the size of the intracellular pool is regulated, which precludes high assimilation rates of both phenylalanine and phe-phe. In waters with relatively low phenylalanine turnover rates, bacterial assemblages appear to have a greater capacity to assimilate phenylalanine and phe-phe simultaneously. Marine bacterial assemblages do not substantially increase the apparent respiration of amino acids when concentrations increase. The authors conclude that sustained increases in uptake rates and mineralization by marine bacterial assemblages in response to an increase in the concentrations of dissolved organic nitrogen is determined by the rate of protein synthesis.

  12. Proteins, Peptides and Amino Acids: Role in Infant Nutrition.

    Science.gov (United States)

    Nutten, Sophie

    2016-01-01

    Proteins are polymers composed of 30 or more amino acids; some of them are essential dietary components, since they are not synthetized by human metabolic processes. They are crucial for healthy growth and development and influence major functions of the body. The infant's first year is a critical time of rapid growth and development, which must be supported by a high rate of protein synthesis. Breast milk, as a single specific food source in the first months of life, is providing the total protein and essential amino acids required. Infant formulas have been designed for infants who cannot be breastfed. They should be similar to breast milk in their composition and their functional outcomes, insuring appropriate growth, optimal development, maturation of the immune system, easy digestion and healthy metabolic programming. By modifying their protein components, specific infant formulas have also been developed for specific needs. For example, partially hydrolyzed (prevention of atopic dermatitis) and extensively hydrolyzed or amino-acid-based infant formulas (reduction in allergy symptoms) have been designed for the management of cow's milk protein allergy. In conclusion, proteins provided via breast milk or infant formula are essential components of the infant's diet; therefore, the specific quality, quantity and conformation of proteins are of utmost importance for healthy growth and development.

  13. On the Maillard reaction of meteoritic amino acids

    Science.gov (United States)

    Kolb, Vera M.; Bajagic, Milica; Liesch, Patrick J.; Philip, Ajish; Cody, George D.

    2006-08-01

    We have performed the Maillard reaction of a series of meteoritic amino acids with sugar ribose under simulated prebiotic conditions, in the solid state at 65°C and at the room temperature. Many meteoritic amino acids are highly reactive with ribose, even at the room temperature. We have isolated high molecular weight products that are insoluble in water, and have studied their structure by the IR (infrared) and solid-state C-13 NMR (nuclear magnetic resonance) spectroscopic methods. The functional groups and their distribution were similar among these products, and were comparable to the previously isolated insoluble organic materials from the Maillard reaction of the common amino acids with ribose. In addition, there were some similarities with the insoluble organic material that is found on Murchison. Our results suggest that the Maillard products may contribute to the composition of the part of the insoluble organic material that is found on Murchison. We have also studied the reaction of sodium silicate solution with the Maillard mixtures, to elucidate the process by which the organic compounds are preserved under prebiotic conditions.

  14. Towards a Mathematical Foundation of Immunology and Amino Acid Chains

    CERN Document Server

    Shen, Wen-Jun; Xiao, Quan-Wu; Guo, Xin; Smale, Stephen

    2012-01-01

    We attempt to set a mathematical foundation of immunology and amino acid chains. To measure the similarities of these chains, a kernel on strings is defined using only the sequence of the chains and a good amino acid substitution matrix (e.g. BLOSUM62). The kernel is used in learning machines to predict binding affinities of peptides to human leukocyte antigens DR (HLA-DR) molecules. On both fixed allele (Nielsen and Lund 2009) and pan-allele (Nielsen et.al. 2010) benchmark databases, our algorithm achieves the state-of-the-art performance. The kernel is also used to define a distance on an HLA-DR allele set based on which a clustering analysis precisely recovers the serotype classifications assigned by WHO (Nielsen and Lund 2009, and Marsh et.al. 2010). These results suggest that our kernel relates well the chain structure of both peptides and HLA-DR molecules to their biological functions, and that it offers a simple, powerful and promising methodology to immunology and amino acid chain studies.

  15. Proteins, Peptides and Amino Acids: Role in Infant Nutrition.

    Science.gov (United States)

    Nutten, Sophie

    2016-01-01

    Proteins are polymers composed of 30 or more amino acids; some of them are essential dietary components, since they are not synthetized by human metabolic processes. They are crucial for healthy growth and development and influence major functions of the body. The infant's first year is a critical time of rapid growth and development, which must be supported by a high rate of protein synthesis. Breast milk, as a single specific food source in the first months of life, is providing the total protein and essential amino acids required. Infant formulas have been designed for infants who cannot be breastfed. They should be similar to breast milk in their composition and their functional outcomes, insuring appropriate growth, optimal development, maturation of the immune system, easy digestion and healthy metabolic programming. By modifying their protein components, specific infant formulas have also been developed for specific needs. For example, partially hydrolyzed (prevention of atopic dermatitis) and extensively hydrolyzed or amino-acid-based infant formulas (reduction in allergy symptoms) have been designed for the management of cow's milk protein allergy. In conclusion, proteins provided via breast milk or infant formula are essential components of the infant's diet; therefore, the specific quality, quantity and conformation of proteins are of utmost importance for healthy growth and development. PMID:27336588

  16. PHARMACOLOGICAL EFFECTS OF SNAKE VENOM L- AMINO ACID OXIDASES

    Directory of Open Access Journals (Sweden)

    Joseph Baby

    2011-02-01

    Full Text Available L-Amino acid oxidases are flavoenzymes which catalyze the stereospecific oxidative deamination of an L-amino acid substrate to a corresponding a-ketoacid with hydrogen peroxide and ammonia production. These enzymes, which are widely distributed in many different organisms, exhibit a marked affinity for hydrophobic amino acids, including phenylalanine, tryptophan, tyrosine, and leucine. Snake venom LAAO induces platelet aggregation and cytotoxicity in various cancer cell lines. The enzyme has antibacterial activity inhibiting the growth of Gram-positive (Bacillus subtilis and Gram-negative (Escherichia coli bacteria. Specific substrates for the isolated protein are L-phenylalanine, L-tryptophan, L-methionine and L-leucine. The enzyme is stable at low temperatures (−20 ºC, −70 ºC and loses its activity by heating at 70 ºC. These enzymes are postulated to be toxins that may be involved in the allergic inflammatory response and specifically associated with mammalian endothelial cells damage. However, in the last decade these enzymes have become an interesting subject for pharmacological, structural and molecular characterizations. Structural and functional investigations of these enzymes can contribute to the advancement of toxinology and to the elaboration of novel therapeutic agents.

  17. Serum amino acid profiles and their alterations in colorectal cancer.

    Science.gov (United States)

    Leichtle, Alexander Benedikt; Nuoffer, Jean-Marc; Ceglarek, Uta; Kase, Julia; Conrad, Tim; Witzigmann, Helmut; Thiery, Joachim; Fiedler, Georg Martin

    2012-08-01

    Mass spectrometry-based serum metabolic profiling is a promising tool to analyse complex cancer associated metabolic alterations, which may broaden our pathophysiological understanding of the disease and may function as a source of new cancer-associated biomarkers. Highly standardized serum samples of patients suffering from colon cancer (n = 59) and controls (n = 58) were collected at the University Hospital Leipzig. We based our investigations on amino acid screening profiles using electrospray tandem-mass spectrometry. Metabolic profiles were evaluated using the Analyst 1.4.2 software. General, comparative and equivalence statistics were performed by R 2.12.2. 11 out of 26 serum amino acid concentrations were significantly different between colorectal cancer patients and healthy controls. We found a model including CEA, glycine, and tyrosine as best discriminating and superior to CEA alone with an AUROC of 0.878 (95% CI 0.815-0.941). Our serum metabolic profiling in colon cancer revealed multiple significant disease-associated alterations in the amino acid profile with promising diagnostic power. Further large-scale studies are necessary to elucidate the potential of our model also to discriminate between cancer and potential differential diagnoses. In conclusion, serum glycine and tyrosine in combination with CEA are superior to CEA for the discrimination between colorectal cancer patients and controls.

  18. A single amino acid gates the KcsA channel

    Energy Technology Data Exchange (ETDEWEB)

    Hirano, Minako, E-mail: hirano37@gpi.ac.jp [Bio Photonics Laboratory, The Graduate School for the Creation of New Photonics Industries, 1955-1 Kurematsu Nishi-ku Hamamatsu, Shizuoka 431-1202 (Japan); Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Okuno, Daichi, E-mail: dokuno@riken.jp [Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Onishi, Yukiko, E-mail: yonishi@riken.jp [Laboratory for Cell Dynamics Observation, Quantitative Biology Center, RIKEN, 6-2-3 Furue-dai Suita, Osaka 565-0874 (Japan); Ide, Toru, E-mail: ide@okayama-u.ac.jp [Graduate School of Natural Science and Technology, Okayama University, 3-1-1 Tsushima-naka Kita-ku Okayama-shi, Okayama 700-8530 (Japan)

    2014-08-08

    Highlights: • pH-dependent gating of the KcsA channel is regulated by the CPD. • E146 is the most essential amino acid for pH sensing by the KcsA. • The protonated-mimicking mutant, E146Q, is constitutively open independent of pH. • Minimal rearrangement of the CPD is sufficient for opening of the KcsA. - Abstract: The KcsA channel is a proton-activated potassium channel. We have previously shown that the cytoplasmic domain (CPD) acts as a pH-sensor, and the charged states of certain negatively charged amino acids in the CPD play an important role in regulating the pH-dependent gating. Here, we demonstrate the KcsA channel is constitutively open independent of pH upon mutating E146 to a neutrally charged amino acid. In addition, we found that rearrangement of the CPD following this mutation was not large. Our results indicate that minimal rearrangement of the CPD, particularly around E146, is sufficient for opening of the KcsA channel.

  19. Amino acids as co-amorphous stabilizers for poorly water-soluble drugs - Part 2

    DEFF Research Database (Denmark)

    Löbmann, K.; Laitinen, R.; Strachan, C.;

    2013-01-01

    spectroscopy. Molecular interactions of the drugs carbamazepine and indomethacin with the amino acids arginine, phenylalanine, and tryptophan were investigated. The amino acids were chosen from the biological target site of both drugs and prepared as co-amorphous formulations together with the drugs...... by vibrational ball milling. A detailed analysis of the FTIR spectra of these formulations revealed specific peak shifts in the vibrational modes of functional groups of drug and amino acid, as long as one amino acid from the biological target site was present in the blends. These peak shifts indicate...... that the drugs formed specific molecular interactions (hydrogen bonding and π-π interactions) with the amino acids. In the drug-amino acid mixtures that contained amino acids which were not present at the biological target site, no such interactions were identified. This study shows the potential of amino acids...

  20. In vivo unnatural amino acid expression in the methylotrophic yeast Pichia pastoris

    Science.gov (United States)

    Young, Travis [San Diego, CA; Schultz, Peter G [La Jolla, CA

    2014-02-11

    The invention provides orthogonal translation systems for the production of polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris. Methods for producing polypeptides comprising unnatural amino acids in methyltrophic yeast such as Pichia pastoris are also provided.

  1. Age-related changes of muscle and plasma amino acids in healthy children.

    Science.gov (United States)

    Hammarqvist, Folke; Angsten, Gertrud; Meurling, Staffan; Andersson, Kerstin; Wernerman, Jan

    2010-07-01

    The aim of the study was to explore if changes in muscle and plasma amino acid concentrations developed during growth and differed from levels seen in adults. The gradient and concentrations of free amino acids in muscle and plasma were investigated in relation to age in metabolic healthy children. Plasma and specimens from the abdominal muscle were obtained during elective surgery. The children were grouped into three groups (group 1: amino acids analysed increased with age, namely taurine, aspartate, threonine, alanine, valine, isoleucine, leucine, histidine, as well as the total sums of branched chain amino acids (BCAA), basic amino acids (BAA) and total sum of amino acids (P amino acids correlated with age (P < 0.05). These results indicate that there is an age dependency of the amino acid pattern in skeletal muscle and plasma during growth.

  2. The Synthesis of Some Novel N-[a-(Isoflavone-7-O-)Acetyl ] Amino Acid Derivatives

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    A series of novel N-[(α)-(isoflavone-7-O-)acetyl] amino acid methyl esters were prepared from the efficient and regioselective alkylation of isoflavones with chloroacetyl amino acid derivatives under mild condition.

  3. Effect of gamma irradiation on the amino acid contents of seafood cooking drips

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Ju Woon; Kim, Yeon Joo; Choi, Jong Il; Kim, Yun Joo; Kim, Jae Hun; Kim, Jin Kyu; Byun, Myung Woo [Advanced Radiation Technology Institute, Korea Atomic Energy Research Institute, Jeongeup (Korea, Republic of); Kwon, Joong Ho [Dept. of Food Science and Technology, Kyungpook National University, Daegu (Korea, Republic of); Ahn, Dong Hyun; Chun, Byung Soo [Faculty of Food Science and Biotechnology, Pukyung Nationol University, Busan (Korea, Republic of)

    2008-11-15

    In this study, the effects of gamma irradiation on the change of structural and free amino acids contents of cooking drips from Hizikia fusiformis (HF) and Enteroctopus dofleini (ED) were investigated. The main structural amino acids were glutamic acid in HF cooking drip, and glutamic acid, glycine, arginine and aspartic acid in ED cooking drip, respectively. The concentrations of structural amino acids in both cooking drip extracts were decreased by the gamma irradiation at the dose of 10 kGy. Especially, the sulfur-containing amino acids were severely degraded by the irradiation. In free amino acid, ED cooking drip extract was contained the larger amount of free amino acid than that of HF cooking drip affecting its rich flavor. The free amino acid concentrations of cooking drips extracts from HF and ED were both increased by irradiation, and it explained the higher protein content by the irradiation.

  4. Effect of amino acids on the interaction between cobalamin(II) and dehydroascorbic acid

    Science.gov (United States)

    Dereven'kov, I. A.; Thi, Thu Thuy Bui; Salnikov, D. S.; Makarov, S. V.

    2016-03-01

    The kinetics of the reaction between one-electron-reduced cobalamin (cobalamin(II), Cb(II)) and the two-electron-oxidized form of vitamin C (dehydroascorbic acid, DHA) with amino acids in an acidic medium is studied by conventional UV-Vis spectroscopy. It is shown that the oxidation of Cbl(II) by dehydroascorbic acid proceeds only in the presence of sulfur-containing amino acids (cysteine, acetylcysteine). A proposed reaction mechanism includes the step of amino acid coordination on the Co(II)-center through the sulfur atom, along with that of the interaction between this complex and DHA molecules, which results in the formation of ascorbyl radical and the corresponding Co(III) thiolate complex.

  5. Use of Attenuated Total Reflectance Mid-Infrared Spectroscopy for Rapid Prediction of Amino Acids in Chinese Rice Wine.

    Science.gov (United States)

    Wu, Zhengzong; Xu, Enbo; Long, Jie; Wang, Fang; Xu, Xueming; Jin, Zhengyu; Jiao, Aiquan

    2015-08-01

    The high content of amino acids of Chinese rice wine (CRW), especially essential amino acids makes it a food increasingly demanded by consumers. Rapid detection technique of amino acid content, which is an important quality and function index of CRW, is highly desirable for consumers, producers as well as administrative authorities. In this study, the potential of Fourier transform infrared spectroscopy (FT-IR) as a novel and rapid analytical technique to determine 17 free amino acids in CRW were investigated. Genetic algorithms (GA) and synergy interval partial least squares (SiPLS) were used to select the most efficient spectral variables to improve the prediction precision of the classic partial least squares (PLS) model constructed on the full-spectrum. The results demonstrated that compared with the PLS model using all wavelengths of FT-IR spectra, the prediction precision of model based on the spectral variables selected by GA and SiPLS was significantly improved, especially for arginine and proline. After systemic comparison and discussion, it was found that GA-SiPLS model achieved the best performance, with the correlation coefficient in calibration (R(2) (cal)) higher than 0.80 and the residual predictive deviation higher than 2.00 for all of the free amino acids analyzed in this study. The overall results confirmed that FT-IR combined with efficient variable selection algorithms is a method that may be useful to replace the traditional methods for routine analysis of free amino acids in CRW.

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

    Science.gov (United States)

    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).

  7. Quantification of glycated N-terminal peptide of hemoglobin using derivatization for multiple functional groups of amino acids followed by liquid chromatography/tandem mass spectrometry.

    Science.gov (United States)

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

    2016-02-01

    A novel method of amino acid analysis using derivatization of multiple functional groups (amino, carboxyl, and phenolic hydroxyl groups) was applied to measure glycated amino acids in order to quantify glycated peptides and evaluate the degree of glycation of peptide. Amino and carboxyl groups of amino acids were derivatized with 1-bromobutane so that the hydrophobicities and basicities of the amino acids, including glycated amino acids, were improved. These derivatized amino acids could be detected with high sensitivity using LC-MS/MS. In this study, 1-deoxyfructosyl-VHLTPE and VHLTPE, which are N-terminal peptides of the β-chains of hemoglobin, were selected as target compounds. After reducing the peptide sample solution with sodium borohydride, the obtained peptides were hydrolyzed with hydrochloric acid. The released amino acids were then derivatized with 1-bromobutane and analyzed with LC-MS/MS. The derivatized amino acids, including glycated amino acids, could be separated using an octadecyl silylated silica column and good sharp peaks were detected. We show a confirmatory experiment that the proposed method can be applied to evaluate the degree of glycation of peptides, using mixtures of glycated and non-glycated peptide.

  8. Effects of Eimeria acervulina infection severity on growth performance, apparent ileal amino acid digestibility, and plasma concentrations of amino acids, carotenoids, and α1-acid glycoprotein in broilers.

    Science.gov (United States)

    Rochell, S J; Parsons, C M; Dilger, R N

    2016-07-01

    An experiment was conducted to evaluate growth performance, apparent ileal digestibility (AID) of amino acids, and plasma concentrations of amino acids, carotenoids, and α1-acid glycoprotein, an acute-phase protein, in broilers inoculated with graded doses of E. acervulina oocysts. Ross 308 male broilers (400 total) were housed in battery cages from 1 to 21 d post-hatch and received common corn-soybean meal-based diets throughout the experiment. At 9 d post-hatch, birds were individually weighed and allotted to 4 treatment groups with 10 replicate cages of 10 birds per cage. At 15 d post-hatch, all birds were inoculated with 1 mL of distilled water that contained 0, 2.5 × 10(5), 5.0 × 10(5), or 1.0 × 10(6) sporulated E. acervulina oocysts. At 21 d, birds were euthanized for collection of blood and ileal digesta. Body weight gain and feed efficiency decreased linearly (P acids by an average of 2.6 percentage units for birds inoculated with 1.0 × 10(6) oocysts compared with uninfected birds. Infection with E. acervulina caused a quadratic decrease (P acid glycoprotein of broilers was not influenced (P > 0.05) by E. acervulina infection. In conclusion, E. acervulina challenge adversely impacted growth performance, plasma carotenoids, and AID of amino acids in a dose-dependent manner. However, plasma amino acid responses to graded E. acervulina inoculation doses varied considerably among amino acids. Thus, these results indicated that alterations in amino acid metabolism caused by E. acervulina infection extended beyond reduced amino acid digestibility.

  9. Amino acid uptake in the skeletal muscle measured using [11C]methylaminoisobutyrate (MEAIB) and PET

    International Nuclear Information System (INIS)

    An amino acid analogue, [11C]MeAIB, recently introduced for oncological positron emission tomography (PET) studies, is a highly selective substrate for insulin-sensitive amino acid transport system A. The aim of this study was to study the uptake kinetics of [11C]MeAIB in skeletal muscle in the fasting state and during insulin stimulation. Two dynamic PET studies were carried out in 11 healthy subjects, once in the fasting state and once during euglycaemic hyperinsulinaemia (serum insulin 67±12 mU l-1). Graphical analysis was used to calculate the fractional [11C]MeAIB uptake rate (Ki). Amino acid uptake was estimated by multiplying Ki by the serum amino acid concentration. After tracer injection, rapid uptake in muscle tissue was detected both in the fasting state and during insulin stimulation and femoral muscles were clearly visualised in both studies. In the graphical analysis, the volume of distribution of [11C]MeAIB plotted against normalised plasma time yielded a linear curve (the slope of which = Ki). The fractional [11C]MeAIB uptake rate (Ki) in the femoral muscle regions increased from 0.0070±0.0018 min-1 (mean±SD) in the fasting state to 0.0079±0.0020 min-1 (P-1 (P-1 (P=0.0001) during hyperinsulinaemia. The calculated skeletal muscle total amino acid uptake and the uptake of the six amino acids typically using system A were similar in the fasting state and during insulin clamp (17.1±3.2 vs 17.7±3.7 μmol kg-1 min-1, NS, and 5.0±1.3 vs 5.0±1.4 μmol kg-1 min-1, NS, respectively). The uptake rates correlated with perfusion both in the fasting state and during hyperinsulinaemia (P11C]MeAIB PET appears to be a feasible method for measurement of amino acid uptake in human skeletal muscle. As a tracer that is not metabolised in the tissues, [11C]MeAIB provides simple modelling and robust data analysis and thus provides a means to investigate amino acid uptake into muscle tissue in various disease conditions known to affect protein metabolism. (orig.)

  10. Application of environmental forensics to identify the sources of ground water contamination using amino acid "finger print"

    Science.gov (United States)

    Choi, J.; Kim, J.; Park, J.; Nam, Y.; Lee, J.; Yoo, E.; Kim, H.; Lee, W.; Choe, S.; Han, J.

    2011-12-01

    The analysis of patterns of amino acids of the leachate from livestock burial site and the wastewater from the manure treatment plant was performed to trace the source of NO3-N contamination in groundwater near mass burial sites. Amino acid was analyzed with LC-MSMS using ODS-II column after the derivatiztion with PITC (phenylisothiocyanate) by following Edman Method. The average concentration of amino acid in the burial leachate was 531.90 mg/L and livestock wastewater was 1.75 mg/L. The concentration of burial leachate is about 300 times higher than that of livestock wastewater. The order of the concentration of each amino acid which were commonly detected in leachate was Valin > Leucine > Isoleucin. On the other hands, livestock wastewater showed different trend (Alanine > Lysine > Valine). Six amino acids among 20 amino acids which were stably detected in leachate and livestock wastewater were selected and compared with peak pattern. By determining the relative ratio of concentrations of amino acids (Ile/Val, Leu/Trp, Val/Trp, Lys/Leu, Lys/Ile, Met/Lys) in the same sample, the sources of the contamination was concluded. Based on this analysis using those indicators, samples affected by livestock wastewater were 43.0% (324 samples) and samples influenced by fertilizer or compost were 57.0% (470 samples) among 754 samples. Any sample among 754 samples didn't seem to be effected by leachate of nearby burial site.

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

    Energy Technology Data Exchange (ETDEWEB)

    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.

  12. A Facile Method for Asymmetric Synthesis of β-Hydroxy-α-amino Acids

    Institute of Scientific and Technical Information of China (English)

    LI,Shuo; LI,Lei; ZHANG,Zhi-Hui; XU,Peng-Fei

    2004-01-01

    @@ β-Hydroxy-a-amino acids are an important class of amino acids due to their inherent biological investigations[1] and as structural components of more complex biomolecules.[2] β-Hydroxy-a-amino acids have been used as intermediates in the asymmetric synthesis of other compounds.[3] An efficient and convenient concise method for the preparation of optically pure enantiomers of β-hydroxy-α-amino acids would be of general interest.

  13. Branched-chain amino acids for hepatic encephalopathy. Protocol for Cochrane Review

    DEFF Research Database (Denmark)

    Gluud, C; Koretz, RL

    2000-01-01

    Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy....

  14. Structure Determination of Cisplatin-Amino Acid Analogues by Infrared Multiple Photon Dissociation Action Spectroscopy

    Science.gov (United States)

    He, Chenchen; Bao, Xun; Zhu, Yanlong; Strobehn, Stephen; Kimutai, Bett; Nei, Y.-W.; Chow, C. S.; Rodgers, M. T.; Gao, Juehan; Oomens, J.

    2015-06-01

    To gain a better understanding of the binding mechanism and assist in the optimization of relevant drug and chemical probe design, both experimental and theoretical studies were performed on a series of amino acid-linked cisplatin derivatives, including glycine-, lysine-, and ornithine-linked cisplatin, Gplatin, Kplatin, and Oplatin, respectively. Cisplatin, the first FDA-approved platinum-based anticancer drug, has been widely used in cancer chemotherapy. Its pharmacological mechanism has been identified as its ability to coordinate to genomic DNA, and guanine is its major target. In previous reports, cisplatin was successfully utilized as a chemical probe to detect solvent accessible sites in ribosomal RNA (rRNA). Among the amino-acid-linked cisplatin derivatives, Oplatin exhibits preference for adenine over guanine. The mechanism behind its different selectivity compared to cisplatin may relate to its potential of forming a hydrogen bond between the carboxylate group in Pt (II) complex and the 6-amino moiety of adenosine stabilizes A-Oplatin products. Tandem mass spectrometry analysis also indicates that different coordination sites of Oplatin on adenosine affect glycosidic bond stability. Infrared multiple photon dissociation (IRMPD) action spectroscopy experiments were performed on all three amino acid-linked cisplatin to characterize their structures. An extensive theoretical study has been performed on Gplatin to guide the selection of the most effective theory and basis set based on its geometric information. The results for Gplatin provide the foundation for characterization of the more complex amino acid-linked cisplatin derivatives, Oplatin and Kplatin. Structural and energetic information elucidated for these compounds, particularly Oplatin reveal the reason for its alternative selectivity compared to cisplatin.

  15. Finding coevolving amino acid residues using row and column weighting of mutual information and multi-dimensional amino acid representation

    DEFF Research Database (Denmark)

    Oliveira, Rodrigo Gouveia; Pedersen, Anders Gorm

    2007-01-01

    ABSTRACT: BACKGROUND: Some amino acid residues functionally interact with each other. This interaction will result in an evolutionary co-variation between these residues - coevolution. Our goal is to find these coevolving residues. RESULTS: We present six new methods for detecting coevolving...... residues. Among other things, we suggest measures that are variants of Mutual Information, and measures that use a multidimensional representation of each residue in order to capture the physico-chemical similarities between amino acids. We created a benchmarking system, in silico, able to evaluate...... these methods through a wide range of realistic conditions. Finally, we use the combination of different methods as a way of improving performance. CONCLUSION: Our best method (Row and Column Weighed Mutual Information) has an estimated accuracy increase of 63% over Mutual Information. Furthermore, we show...

  16. Free amino acids in atmospheric particulate matter of Venice, Italy

    Science.gov (United States)

    Barbaro, Elena; Zangrando, Roberta; Moret, Ivo; Barbante, Carlo; Cescon, Paolo; Gambaro, Andrea

    2011-09-01

    The concentrations of free amino acids were determined in atmospheric particulate matter from the city of Venice (Italy) in order to better understand their origin. The analysis of aerosol samples was carried out via high-performance liquid chromatography coupled to a triple quadrupole tandem mass spectrometric detector (HPLC/ESI-MS/MS). The internal standard method was used and the analytical procedure was validated by evaluating the trueness, the precision, the recovery, the detection and the quantification limits. The particulate matter was collected using quartz fiber filters and extracted in methanol; after filtration the extract was directly analyzed. Forty samples were collected from April to October 2007 and the average concentrations of free amino acids in the aerosol were: alanine 35.6 pmol m -3, aspartic acid 31.1 pmol m -3, glycine 30.1 pmol m -3, glutamic acid 32.5 pmol m -3, isoleucine 2.4 pmol m -3, leucine 2.7 pmol m -3, methionine, cystine and 3-hydroxy-proline below the limit of detection, phenylalanine 2.8 pmol m -3, proline 43.3 pmol m -3, serine 8.6 pmol m -3, threonine 2.8 pmol m -3, tyrosine 1.7 pmolm -3, valine 3.8 pmol m -3, asparagine 70.2 pmol m -3, glutamine 38.0 pmol m -3, 4-hydroxy-proline 2.5 pmol m -3, methionine sulfoxide 1.1 pmol m -3, and methionine sulfone 0.1 pmol m -3. The total average concentration of these free amino acids in aerosol samples of Venice Lagoon was 334 pmol m -3. The temporal evolution and multivariate analysis indicated the photochemical origin of 4-hydroxy-proline and methionine sulfoxide and for other compounds an origin further away from the site of sampling, presumably reflecting transport from terrestrial sources.

  17. Thermodynamics of Ion Pair Formations Between Charged Poly(Amino Acid)s.

    Science.gov (United States)

    Petrauskas, Vytautas; Maximowitsch, Eglė; Matulis, Daumantas

    2015-09-17

    Electrostatic interactions between the positively and negatively charged amino acids in proteins play an important role in macromolecular stability, binding, and recognition. Numerous amino acids in proteins are ionizable and may exist in negatively (e.g., Glu, Asp, Cys, Tyr) or positively (e.g., Arg, Lys, His, Orn) charged form dependent on pH and their pKas. In this work, isothermal titration calorimetry was used to determine the average standard values of thermodynamic parameters (the Gibbs free energy, enthalpy, entropy, and the heat capacity) of interaction between the positively charged amino acid homopolymers (polyarginine, polylysine, and polyornithine) and the negatively charged homopolymers (polyaspartic and polyglutamic acids). These values are of potential use in the computational models of interacting proteins and other biological macromolecules. The study showed that oppositely charged poly(amino acid)s bound each other with the stoichiometry of one positive to one negative charge. Arginine bound to the negatively charged amino acids with exothermic enthalpy and higher affinity than lysine. This result also suggests that positive charges in proteins should not be considered entirely equivalent if carried by lysine or arginine. The difference in binding energy of arginine and lysine association with the negatively charged amino acids was attributed to the enthalpy of the second ionic hydrogen bond formation between the guanidine and carboxylic groups. Despite the favorable enthalpic contribution, all such ion pair formation reactions were largely entropy-driven. Consistent with previously observed ionic interactions, the positive heat capacity was always observed during the amino acid ion pair formation.

  18. Inhibitory and excitatory amino acids in the cerebrospinal fluid of children with two types of cerebral palsy

    Institute of Scientific and Technical Information of China (English)

    Haibin Yuan; Li Wang; Fei Yin; Li Li; Jing Peng

    2008-01-01

    BACKGROUND: Under normal conditions, excitatory amino acids are dynamically balanced with inhibitory amino acids. Excitatory amino acids have been implicated in perinatal brain injury. OBJECTIVE: To investigate differences in the levels of the excitatory amino acids glutamic acid and aspartic acid, and the inhibitory amino acid gamma-aminobutyric acid (GABA) in the cerebrospinal fluid (CSF) of children with spastic cerebral palsy or athetotic cerebral palsy. DESIGN, TIME AND SETTING: Case-control exploratory observation of neurotransmitter in patients. The experiment was performed in the Pediatrics Department of the Second Affiliated Hospital of Changsba Medical College, the Cerebral Palsy Center of Xiangtan Affiliated Hospital of South China University and the Pediatrics Department of Xiangya Hospital, between February 2006 and May 2007. PARTICIPANTS: We selected 27 children with cerebral palsy, including 13 with spastic cerebral palsy and 14 with athetotic cerebral palsy. We selected 10 patients who were not affected by any neurological disease as controls. METHODS: Two mL blood-free CSF was harvested between the third and fourth lumbar vertebrae of each patient after anesthesia, and stored at 70℃. One mL CSF was mixed with 10 mg sulfosalicylic acid and placed in ice-bath for 10 minutes, then centrifuged 2 000 g for 10 minutes. The supernatant was collected for amino acid quantitation. MAIN OUTCOME MEASURES: The concentrations of glutamic acid, aspartic acid and GABA in the CSF were determined by high-performance liquid chromatography and fluorometric method. The correlation of glutamie acid, aspartic acid and GABA levels with muscular tension in children with cerebral palsy was analyzed using linear dependence. RESULTS: The concentration of GABA was significantly lower in both spastic cerebral palsy and athetotic cerebral palsy patients than in the control group (P 0.05). CONCLUSION: Spastic cerebral palsy and athetotic cerebral palsy patients exhibit an

  19. Chemical composition and ruminal degradation kinetics of crude protein and amino acids, and intestinal digestibility of amino acids from tropical forages

    Directory of Open Access Journals (Sweden)

    Lidia Ferreira Miranda

    2012-03-01

    Full Text Available The objective of this research was to determine the chemical composition and ruminal degradation of the crude protein (CP, total and individual amino acids of leaves from tropical forages: perennial soybean (Neonotonia wightii, cassava (Manihot esculenta, leucaena (Leucaena leucocephala and ramie (Boehmeria nivea, and to estimate the intestinal digestibility of the rumen undegradable protein (RUDP and individual amino acids of leaves from the tropical forages above cited, but including pigeon pea (Cajanus cajan. Three nonlactating Holstein cows were used to determine the in situ ruminal degradability of protein and amino acids from leaves (6, 18 and 48 hours of ruminal incubation. For determination of the intestinal digestibility of RUDP, the residue from ruminal incubation of the materials was used for 18 hours. A larger concentration of total amino acids for ramie and smaller for perennial soybean were observed; however, they were very similar in leucaena and cassava. Leucine was the essential amino acid of greater concentration, with the exception of cassava, which exhibited a leucine concentration 40.45% smaller. Ramie showed 14.35 and 22.31% more lysine and methionine, respectively. The intestinal digestibility of RUDP varied from 23.56; 47.87; 23.48; 25.69 and 10.86% for leucaena, perennial soybean, cassava, ramie and pigeon pea, respectively. The individual amino acids of tropical forage disappeared in different extensions in the rumen. For the correct evaluation of those forages, one should consider their composition of amino acids, degradations and intestinal digestibility, once the amino acid composition of the forage does not reflect the amino acid profiles that arrived in the small intestine. Differences between the degradation curves of CP and amino acids indicate that degradation of amino acids cannot be estimated through the degradation curve of CP, and that amino acids are not degraded in a similar degradation profile.

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

    Energy Technology Data Exchange (ETDEWEB)

    Cobb, Alyssa K.; Pudritz, Ralph E., E-mail: cobbak@mcmaster.ca, E-mail: pudritz@physics.mcmaster.ca [Origins Institute, McMaster University, ABB 241, 1280 Main Street, Hamilton, ON L8S 4M1 (Canada)

    2014-03-10

    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 and 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.