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Sample records for aromatic amino acids

  1. Side Chain Cyclized Aromatic Amino Acids

    DEFF Research Database (Denmark)

    Van der Poorten, Olivier; Knuhtsen, Astrid; Sejer Pedersen, Daniel

    2016-01-01

    Constraining the conformation of flexible peptides is a proven strategy to increase potency, selectivity, and metabolic stability. The focus has mostly been on constraining the backbone dihedral angles; however, the correct orientation of the amino acid side chains (χ-space) that constitute...... the peptide pharmacophore is equally important. Control of χ-space utilizes conformationally constrained amino acids that favor, disfavor, or exclude the gauche (-), the gauche (+), or the trans conformation. In this review we focus on cyclic aromatic amino acids in which the side chain is connected...... to the peptide backbone to provide control of χ(1)- and χ(2)-space. The manifold applications for cyclized analogues of the aromatic amino acids Phe, Tyr, Trp, and His within peptide medicinal chemistry are showcased herein with examples of enzyme inhibitors and ligands for G protein-coupled receptors....

  2. 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.

  3. 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.

  4. 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.

  5. [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.

  6. Structural insights into the regulation of aromatic amino acid hydroxylation

    OpenAIRE

    Fitzpatrick, Paul F.

    2015-01-01

    The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are homotetramers, with each subunit containing a homologous catalytic domain and a divergent regulatory domain. The solution structure of the regulatory domain of tyrosine hydroxylase establishes that it contains a core ACT domain similar to that in phenylalanine hydroxylase. The isolated regulatory domain of tyrosine hydroxylase forms a stable dimer, while that of phenylalanine h...

  7. The Nature of Intermolecular Interactions Between Aromatic Amino Acid Residues

    Energy Technology Data Exchange (ETDEWEB)

    Gervasio, Francesco; Chelli, Riccardo; Procacci, Piero; Schettino, Vincenzo

    2002-05-01

    The nature of intermolecular interactions between aromatic amino acid residues has been investigated by a combination of molecular dynamics and ab initio methods. The potential energy surface of various interacting pairs, including tryptophan, phenilalanine, and tyrosine, was scanned for determining all the relevant local minima by a combined molecular dynamics and conjugate gradient methodology with the AMBER force field. For each of these minima, single-point correlated ab initio calculations of the binding energy were performed. The agreement between empirical force field and ab initio binding energies of the minimum energy structures is excellent. Aromatic-aromatic interactions can be rationalized on the basis of electrostatic and van der Waals interactions, whereas charge transfer or polarization phenomena are small for all intermolecular complexes and, particularly, for stacked structures.

  8. 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)

  9. Adsorption of aromatic amino acids in a fixed bed column

    Directory of Open Access Journals (Sweden)

    M.A. Cremasco

    2003-09-01

    Full Text Available Phenylalanine (Phe and tyrosine (Tyr are two of the twenty amino acids in proteins; they are classified as aromatic amino acids, because both have a benzene ring in their structures. These amino acids are important in the synthesis of several biologically active amines, such as beta-endorphin, a neurotransmitter. Amino acids can be separated by ion-exchange chromatography. In this case, it is important that fixed-bed adsorber design adequately predict the breakthrough curve. This work presents a mathematical model for both fluid and porous phases. In the solution proposed for this model the liquid-phase concentration inside the particles is solved analytically and is related to the liquid-phase concentration in the bed using Duhamel's theorem. The solution for liquid-phase concentration in the bed is then solved numerically instead of analytically. The basic mass transfer parameters are from the literature. The results from the model are compared with those obtained experimentally using Phe and Tyr diluted in aqueous solutions in a fixed bed of PVP (poly-4-vinylpyridine resin.

  10. 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.

  11. Multicenter bond index analysis of influence of metal cations on the aromaticity of aromatic amino acids: Phenylalanine and tyrosine

    Science.gov (United States)

    Pakiari, A. H.; Farrokhnia, M.; Azami, S. M.

    2008-05-01

    In order to provide insight into the influence of metal cations on the aromaticity of amino acids, evaluation of six-center delocalization indices is accomplished in the context of quantum theory of atoms in molecules (QTAIM). Aromaticity of two amino acids, phenylalanine and tyrosine, is investigated as typical amino acids containing aromatic ring in their isolated state and complexed by some metal cations. The results showed that the metal cations affect the most important three connectivities differently. Also, it is shown that the existence of metal cations can increase two-center delocalization in certain parts of the aromatic rings.

  12. Structural insights into the regulation of aromatic amino acid hydroxylation.

    Science.gov (United States)

    Fitzpatrick, Paul F

    2015-12-01

    The aromatic amino acid hydroxylases phenylalanine hydroxylase, tyrosine hydroxylase, and tryptophan hydroxylase are homotetramers, with each subunit containing a homologous catalytic domain and a divergent regulatory domain. The solution structure of the regulatory domain of tyrosine hydroxylase establishes that it contains a core ACT domain similar to that in phenylalanine hydroxylase. The isolated regulatory domain of tyrosine hydroxylase forms a stable dimer, while that of phenylalanine hydroxylase undergoes a monomer-dimer equilibrium, with phenylalanine stabilizing the dimer. These solution properties are consistent with the regulatory mechanisms of the two enzymes, in that phenylalanine hydroxylase is activated by phenylalanine binding to an allosteric site, while tyrosine hydroxylase is regulated by binding of catecholamines in the active site.

  13. Metabolic engineering for microbial production of aromatic amino acids and derived compounds.

    Science.gov (United States)

    Bongaerts, J; Krämer, M; Müller, U; Raeven, L; Wubbolts, M

    2001-10-01

    Metabolic engineering to design and construct microorganisms suitable for the production of aromatic amino acids and derivatives thereof requires control of a complicated network of metabolic reactions that partly act in parallel and frequently are in rapid equilibrium. Engineering the regulatory circuits, the uptake of carbon, the glycolytic pathway, the pentose phosphate pathway, and the common aromatic amino acid pathway as well as amino acid importers and exporters that have all been targeted to effect higher productivities of these compounds are discussed.

  14. PcMtr, an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum

    OpenAIRE

    Trip, H; EVERS, ME; Driessen, AJM

    2004-01-01

    The gene encoding an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum was cloned, functionally expressed and characterized in Saccharomyces cerevisiae M4276. The permease, designated PcMtr, is structurally and functionally homologous to Mtr of Neurospora crassa, and unrelated to the Amino Acid Permease (AAP) family which includes most amino acid permeases in fungi. Database searches of completed fungal genome sequences reveal that Mtr type permeases are not widely...

  15. [Asymmetric synthesis of aromatic L-amino acids catalyzed by transaminase].

    Science.gov (United States)

    Xia, Wenna; Sun, Yu; Min, Cong; Han, Wei; Wu, Sheng

    2012-11-01

    Aromatic L-Amino acids are important chiral building blocks for the synthesis of many drugs, pesticides, fine chemicals and food additives. Due to the high activity and steroselectivity, enzymatic synthesis of chiral building blocks has become the main research direction in asymmetric synthesis field. Guided by the phylogenetic analysis of transaminases from different sources, two representative aromatic transaminases TyrB and Aro8 in type I subfamily, from the prokaryote Escherichia coli and eukaryote Saccharomyces cerevisia, respectively, were applied for the comparative study of asymmetric transamination reaction process and catalytic efficiency of reversely converting keto acids to the corresponding aromatic L-amino acid. Both TyrB and Aro8 could efficiently synthesize the natural aromatic amino acids phenylalanine and tyrosine as well as non-natural amino acid phenylglycine. The chiral HPLC analysis showed the produced amino acids were L-configuration and the e.e value was 100%. L-alanine was the optimal amino donor, and the transaminase TyrB and Aro8 could not use D-amino acids as amino donor. The optimal molar ratio of amino donor (L-alanine) and amino acceptor (aromatic alpha-keto acids) was 4:1. Both of the substituted group on the aromatic ring and the length of fatty acid carbon chain part in the molecular structure of aromatic substrate alpha-keto acid have the significant impact on the enzyme-catalyzed transamination efficiency. In the experiments of preparative-scale transamination synthesis of L-phenylglycine, L-phenylalanine and L-tyrosine, the specific production rate catalyzed by TryB were 0.28 g/(g x h), 0.31 g/(g x h) and 0.60 g/(g x h) and the specific production rate catalyzed by Aro8 were 0.61 g/(g x h), 0.48 g/(g x h) and 0.59 g/(g x h). The results obtained here were useful for applying the transaminases to asymmetric synthesis of L-amino acids by reversing the reaction balance in industry.

  16. Evidence that phenylalanine may not provide the full needs for aromatic amino acids in children.

    Science.gov (United States)

    Hsu, Jean W C; Ball, Ronald O; Pencharz, Paul B

    2007-03-01

    Phenylalanine is nutritionally classified as an indispensable amino acid and can be converted to tyrosine by phenylalanine hydroxylation. The initial goal of the present study was to determine the aromatic amino acid (phenylalanine plus tyrosine) requirements in healthy children fed a diet without tyrosine by using the indicator amino acid oxidation (IAAO) method using lysine as the indicator amino acid. Healthy school-age children (n = 5) were fed in random order a diet with eight graded intakes of phenylalanine without tyrosine. The requirement was determined by the rate of recovery of CO2 from L-[1-C]lysine oxidation (FCO2). Phenylalanine (total aromatic amino acid) requirement, in the absence of tyrosine, for children was determined to be 28 mg/kg/d, which was only 64% of the adult requirement, which is biologically absurd. A possible reason for the lower estimate of phenylalanine requirement could be lower phenylalanine hydroxylation rate in children, which is supported by the finding of lower urinary tyrosine/phenylalanine ratios in children compared with adults. In conclusion, this study indicates that phenylalanine may not provide the total needs for aromatic amino acids in children fed an amino acid-based diet without tyrosine.

  17. Branched-chain and aromatic amino acid catabolism into aroma volatiles in Cucumis melo L. fruit.

    Science.gov (United States)

    Gonda, Itay; Bar, Einat; Portnoy, Vitaly; Lev, Shery; Burger, Joseph; Schaffer, Arthur A; Tadmor, Ya'akov; Gepstein, Shimon; Giovannoni, James J; Katzir, Nurit; Lewinsohn, Efraim

    2010-02-01

    The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty acids, carotenoids, amino acids, and terpenes. Although amino acids are known precursors of aroma compounds in the plant kingdom, the initial steps in the catabolism of amino acids into aroma volatiles have received little attention. Incubation of melon fruit cubes with amino acids and alpha-keto acids led to the enhanced formation of aroma compounds bearing the side chain of the exogenous amino or keto acid supplied. Moreover, L-[(13)C(6)]phenylalanine was also incorporated into aromatic volatile compounds. Amino acid transaminase activities extracted from the flesh of mature melon fruits converted L-isoleucine, L-leucine, L-valine, L-methionine, or L-phenylalanine into their respective alpha-keto acids, utilizing alpha-ketoglutarate as the amine acceptor. Two novel genes were isolated and characterized (CmArAT1 and CmBCAT1) encoding 45.6 kDa and 42.7 kDa proteins, respectively, that displayed aromatic and branched-chain amino acid transaminase activities, respectively, when expressed in Escherichia coli. The expression of CmBCAT1 and CmArAT1 was low in vegetative tissues, but increased in flesh and rind tissues during fruit ripening. In addition, ripe fruits of climacteric aromatic cultivars generally showed high expression of CmBCAT1 and CmArAT1 in contrast to non-climacteric non-aromatic fruits. The results presented here indicate that in melon fruit tissues, the catabolism of amino acids into aroma volatiles can initiate through a transamination mechanism, rather than decarboxylation or direct aldehyde synthesis, as has been demonstrated in other plants.

  18. Oxidation of aromatic alcohols on zeolite-encapsulated copper amino acid complexes

    Energy Technology Data Exchange (ETDEWEB)

    Ernst, S.; Teixeira Florencio, J.M. [Kaiserslautern Univ. (Germany). Dept. of Chemistry, Chemical Technology

    1998-12-31

    Copper complexes of the amino acids histidine, arginine and lysine have been introduced into the supercages of zeolite Y and, for the first time, into the large intracrystalline cavities of zeolites EMT and MCM-22. The resulting host/guest compounds are characterized by X-ray powder diffraction, UV/VIS-spectroscopy in the diffuse reflectance mode and by catalytic tests in the liquid-phase oxidation of aromatic alcohols (viz. benzyl alcohol, 2- and 3-methylbenzyl alcohol and 2,5-dimethylbenzyl alcohol) with tertiary-butylhydroperoxide as oxidant. It was observed that intracrystalline copper-amino acid complexes possess remarkable catalytic activity, yielding the corresponding aromatic aldehydes and acids. (orig.)

  19. Equivalent Isopropanol Concentrations of Aromatic Amino Acids Interactions with Lipid Vesicles.

    Science.gov (United States)

    Johnson, Merrell A; Ray, Bruce D; Wassall, Stephen R; Petrache, Horia I

    2015-08-01

    We show that the interaction of aromatic amino acids with lipid bilayers can be characterized by conventional 1D [Formula: see text]H NMR spectroscopy using reference spectra obtained in isopropanol-d8/D[Formula: see text]O solutions. We demonstrate the utility of this method with three different peptides containing tyrosine, tryptophan, or phenylalanine amino acids in the presence of 1,2-dioleoyl-sn-glycero-3-phosphocholine or 1,2-dioleoyl-sn-glycero-3-phosphoserine lipid membranes. In each case, we determine an equivalent isopropanol concentration (EIC) for each hydrogen site of aromatic groups, in essence constructing a map of the chemical environment. These EIC maps provide information on relative affinities of aromatic side chains for either PC or PS bilayers and also inform on amino acid orientation preference when bound to membranes.

  20. EXTRACTION-CHROMATOGRAPHIC DETERMINATION OF GLUCOSE AND FRUCTOSE IN THE PRESENCE OF AROMATIC AMINO ACIDS

    Directory of Open Access Journals (Sweden)

    Y. I. Korenman

    2012-01-01

    Full Text Available The extraction of glucose and fructose from aqueous salt solutions containing aromatic amino acids (phenylalanine, tryptophan, tyrosine, hydrophilic solvents (aliphatic alcohols, alkyl acetates, ketones have been studied. The quantitative characteric of the process (the distribution coefficients, the degree of extraction, separation factors are calculeted. The dependence of distribution ratios of monosaccharides from the amino acid content in the solution has been established. A mobile phase for analysis of the concentrate by ascending thin layer chromatography have been developed.

  1. Production of dopamine by aromatic L-amino acid decarboxylase cells after spinal cord injury

    DEFF Research Database (Denmark)

    Ren, Liqun; Wienecke, Jacob; Hultborn, Hans;

    2016-01-01

    Aromatic L-amino acid decarboxylase (AADC) cells are widely distributed in the spinal cord and their functions are largely unknown. We have previously found that AADC cells in the spinal cord could increase their ability to produce serotonin from 5-hydroxytryptophan after spinal cord injury (SCI)...

  2. Regulation of aromatic amino acid biosynthesis in the ribulose monophosphate cycle methylotroph Nocardia sp. 239

    NARCIS (Netherlands)

    Boer, L. de; Vrijbloed, J.W.; Grobben, G.; Dijkhuizen, L.

    1989-01-01

    The regulation of aromatic amino acid biosynthesis in Nocardia sp. 239 was studied. In cell-free extracts 3-deoxy-D-arabinoheptulosonate 7-phosphate (DAHP) synthase activity was inhibited in a cumulative manner by tryptophan, phenylalanine and tyrosine. Chorismate mutase was inhibited by both phenyl

  3. Clinical and biochemical features of aromatic L-amino acid decarboxylase deficiency.

    NARCIS (Netherlands)

    Brun, L.; Ngu, L.H.; Keng, W.T.; Ch'ng, G.S.; Choy, Y.S.; Hwu, W.L.; Lee, W.T.; Willemsen, M.A.A.P.; Verbeek, M.M.; Wassenberg, T.; Regal, L.; Orcesi, S.; Tonduti, D.; Accorsi, P.; Testard, H.; Abdenur, J.E.; Tay, S.; Allen, G.F.; Heales, S.; Kern, I.; Kato, M.; Burlina, A.; Manegold, C.; Hoffmann, G.F.; Blau, N.

    2010-01-01

    OBJECTIVE: To describe the current treatment; clinical, biochemical, and molecular findings; and clinical follow-up of patients with aromatic l-amino acid decarboxylase (AADC) deficiency. METHOD: Clinical and biochemical data of 78 patients with AADC deficiency were tabulated in a database of pediat

  4. PcMtr, an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum

    NARCIS (Netherlands)

    Trip, H; Evers, ME; Driessen, AJM

    2004-01-01

    The gene encoding an aromatic and neutral aliphatic amino acid permease of Penicillium chrysogenum was cloned, functionally expressed and characterized in Saccharomyces cerevisiae M4276. The permease, designated PcMtr, is structurally and functionally homologous to Mtr of Neurospora crassa, and unre

  5. Protein Quantification by Derivatization-Free High-Performance Liquid Chromatography of Aromatic Amino Acids

    Science.gov (United States)

    Hesse, Almut

    2016-01-01

    Amino acid analysis is considered to be the gold standard for quantitative peptide and protein analysis. Here, we would like to propose a simple HPLC/UV method based on a reversed-phase separation of the aromatic amino acids tyrosine (Tyr), phenylalanine (Phe), and optionally tryptophan (Trp) without any derivatization. The hydrolysis of the proteins and peptides was performed by an accelerated microwave technique, which needs only 30 minutes. Two internal standard compounds, homotyrosine (HTyr) and 4-fluorophenylalanine (FPhe) were used for calibration. The limit of detection (LOD) was estimated to be 0.05 µM (~10 µg/L) for tyrosine and phenylalanine at 215 nm. The LOD for a protein determination was calculated to be below 16 mg/L (~300 ng BSA absolute). Aromatic amino acid analysis (AAAA) offers excellent accuracy and a precision of about 5% relative standard deviation, including the hydrolysis step. The method was validated with certified reference materials (CRM) of amino acids and of a pure protein (bovine serum albumin, BSA). AAAA can be used for the quantification of aromatic amino acids, isolated peptides or proteins, complex peptide or protein samples, such as serum or milk powder, and peptides or proteins immobilized on solid supports. PMID:27559481

  6. Aromatic Amino Acids-Guanidinium Complexes through Cation-π Interactions

    Directory of Open Access Journals (Sweden)

    Cristina Trujillo

    2015-05-01

    Full Text Available Continuing with our interest in the guanidinium group and the different interactions than can establish, we have carried out a theoretical study of the complexes formed by this cation and the aromatic amino acids (phenylalanine, histidine, tryptophan and tyrosine using DFT methods and PCM-water solvation. Both hydrogen bonds and cation-π interactions have been found upon complexation. These interactions have been characterized by means of the analysis of the molecular electron density using the Atoms-in-Molecules approach as well as the orbital interactions using the Natural Bond Orbital methodology. Finally, the effect that the cation-π and hydrogen bond interactions exert on the aromaticity of the corresponding amino acids has been evaluated by calculating the theoretical NICS values, finding that the aromatic character was not heavily modified upon complexation.

  7. Engineering Escherichia coli to overproduce aromatic amino acids and derived compounds.

    Science.gov (United States)

    Rodriguez, Alberto; Martínez, Juan A; Flores, Noemí; Escalante, Adelfo; Gosset, Guillermo; Bolivar, Francisco

    2014-09-09

    The production of aromatic amino acids using fermentation processes with recombinant microorganisms can be an advantageous approach to reach their global demands. In addition, a large array of compounds with alimentary and pharmaceutical applications can potentially be synthesized from intermediates of this metabolic pathway. However, contrary to other amino acids and primary metabolites, the artificial channelling of building blocks from central metabolism towards the aromatic amino acid pathway is complicated to achieve in an efficient manner. The length and complex regulation of this pathway have progressively called for the employment of more integral approaches, promoting the merge of complementary tools and techniques in order to surpass metabolic and regulatory bottlenecks. As a result, relevant insights on the subject have been obtained during the last years, especially with genetically modified strains of Escherichia coli. By combining metabolic engineering strategies with developments in synthetic biology, systems biology and bioprocess engineering, notable advances were achieved regarding the generation, characterization and optimization of E. coli strains for the overproduction of aromatic amino acids, some of their precursors and related compounds. In this paper we review and compare recent successful reports dealing with the modification of metabolic traits to attain these objectives.

  8. Liquid-liquid distribution of aromatic α-amino acids in multicomponent systems

    Science.gov (United States)

    Korenman, Ya. I.; Mokshina, N. Ya.; Pakhomova, O. A.

    2010-02-01

    Distribution coefficients and recovery factors of phenylalanine, tyrosine, and tryptophan are measured in extraction systems with butanol, pentanol, acetone, and ethyl acetate, their binary and ternary mixtures, and water-soluble polymers. Extraction conditions—extractant composition, salting-out agents, and pH—are optimized. Efficient systems providing maximum quantitative characteristics of the process of liquid-liquid distribution of aromatic α-amino acids are proposed.

  9. Prediction of Intramolecular Polarization of Aromatic Amino Acids Using Kriging Machine Learning.

    Science.gov (United States)

    Fletcher, Timothy L; Davie, Stuart J; Popelier, Paul L A

    2014-09-09

    Present computing power enables novel ways of modeling polarization. Here we show that the machine learning method kriging accurately captures the way the electron density of a topological atom responds to a change in the positions of the surrounding atoms. The success of this method is demonstrated on the four aromatic amino acids histidine, phenylalanine, tryptophan, and tyrosine. A new technique of varying training set sizes to vastly reduce training times while maintaining accuracy is described and applied to each amino acid. Each amino acid has its geometry distorted via normal modes of vibration over all local energy minima in the Ramachandran map. These geometries are then used to train the kriging models. Total electrostatic energies predicted by the kriging models for previously unseen geometries are compared to the true energies, yielding mean absolute errors of 2.9, 5.1, 4.2, and 2.8 kJ mol(-1) for histidine, phenylalanine, tryptophan, and tyrosine, respectively.

  10. Biomolecular interactions of emerging two-dimensional materials with aromatic amino acids

    Science.gov (United States)

    Mallineni, Sai Sunil Kumar; Karakaya, Mehmet; Podila, Ramakrishna; Rao, Apparao

    The present work experimentally investigates the interaction of aromatic amino acids, viz., tyrosine, tryptophan, and phenylalanine with novel two-dimensional (2D) materials including graphene (G), graphene oxide (GO), and boron nitride (BN). Photoluminescence, micro-Raman spectroscopy and cyclic voltammetry were employed to investigate the nature of interactions and possible charge transfer between 2D materials and amino acids. Consistent with previous theoretical studies, graphene and BN were observed to interact with amino acids through π- π interactions. Furthermore, we found that GO exhibits strong interactions with tryptophan and tyrosine as compared to graphene and BN, which we attribute to the formation of H-bonds between tryptophan and GO as shown theoretically in Ref. 2. On the other hand, phenylalanine did not exhibit much difference in interactions with G, GO, and BN. Clemson Nanomaterials Center, Clemson University, Clemson, SC, USA.

  11. 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.

  12. Relevance of Aromatic Amino Acids for Electron Conduction along Geobacter Pili Protein

    Science.gov (United States)

    Adhikari, Ramesh; Malvankar, Nikhil; Tuominen, Mark; Lovley, Derek

    It has been proposed that the charge transport though Geobacter sulfurreducens pili protein occurs through the aromatic amino acids forming helical conducting chain within pili. X-ray studies of pili show that the aromatic amino acids are packed close enough (3-4 Å) for pi-stacking to occur. Conductivity of the pili network increases with lowering temperature indicating metallic-like transport mechanism. However due to the complexity of charge percolation path in 3D network, the intrinsic conductivity of an individual pili was not known. Here, we report transport measurements of individual pili of G. sulfurreducens. The conductivity, similar to that of organic polymers, shows that the pili may have implications in materials research. In addition, the conductivity value is sufficient to explain the respiration rate of the G. sulfurreducens. Further studies of pili from different natural and genetically modified species with varying amount of aromatic amino acid density demonstrate that it can play a decisive role on the magnitude of the conductivity. This research was supported by the Office of Naval Research (ONR) and National Science Foundation (NSF) Center for Hierarchical Manufacturing (CHM). Nikhil S. Malvankar holds a Career Award from the Burroughs Wellcome Fund.

  13. Cloning and expression of Chromobacterium violaceum phenylalanine hydroxylase in Escherichia coli and comparison of amino acid sequence with mammalian aromatic amino acid hydroxylases.

    Science.gov (United States)

    Onishi, A; Liotta, L J; Benkovic, S J

    1991-10-05

    The complete amino acid sequence (296 amino acids) of Chromobacterium violaceum phenylalanine hydroxylase (PAH) was determined by nucleotide analysis of a DNA clone isolated using both a synthetic oligonucleotide probe based on the NH2-terminal amino acid sequence and an antibody against this enzyme. The ApaL I fragment (approximately 1.9 kilobase pairs) containing the entire PAH gene was subcloned in pBluescript II and induced by isopropyl-beta-D-thiogalactopyranoside. In order to eliminate fusion proteins the XbaI/ClaI fragment which contained the PAH gene from the Bluescript construct was subcloned into pMAC 5-8 containing the TAC promoter. The recombinant protein reacts with antibody raised to authentic C. violaceum PAH and its NH2-terminal 20-amino acid sequence and COOH-terminal amino acid residue were identical with the wild-type protein. Key physical and chemical characteristics of the recombinant protein, i.e. its copper content and Michaelis-Menten parameters, were the same as wild-type. Comparison of amino acid sequences revealed a highly conserved region between C. violaceum PAH and three different mammalian aromatic amino acid hydroxylases. This conserved area may well be a catalytically important domain of these pterin- and metal-requiring aromatic amino acid hydroxylases. The over-expression of C. violaceum PAH in Escherichia coli will facilitate the analysis of the enzyme mechanism by various spectroscopic methods.

  14. Electronic structure of aromatic amino acids studied by soft x-ray spectroscopy

    Science.gov (United States)

    Zhang, Wenhua; Carravetta, Vincenzo; Plekan, Oksana; Feyer, Vitaliy; Richter, Robert; Coreno, Marcello; Prince, Kevin C.

    2009-07-01

    The electronic structure of phenylalanine, tyrosine, tryptophan, and 3-methylindole in the gas phase was investigated by x-ray photoemission spectroscopy (XPS) and near edge x-ray absorption fine structure (NEXAFS) spectroscopy at the C, N, and O K-edges. The XPS spectra have been calculated for the four principal conformers of each amino acid, and the spectra weighted by the Boltzmann population ratios calculated from published free energies. Instead of the single peaks expected from the stoichiometry of the compounds, the N 1s core level spectra of phenylalanine and tryptophan show features indicating that more than one conformer is present. The calculations reproduce the experimental features. The C and O 1s spectra do not show evident effects due to conformational isomerism. The calculations predict that such effects are small for carbon, and for oxygen it appears that only broadening occurs. The carbon K-edge NEXAFS spectra of these aromatic amino acids are similar to the published data of the corresponding molecules in the solid state, but show more structure due to the higher resolution in the present study. The N K-edge spectra of tryptophan and 3-methylindole differ from phenylalanine and tyrosine, as the first two both contain a nitrogen atom located in a pyrrole ring. The nitrogen K-edge NEXAFS spectra of aromatic amino acids do not show any measurable effects due to conformational isomerism, in contrast to the photoemission results. Calculations support this result and show that variations of the vertical excitation energies of different conformers are small, and cannot be resolved in the present experiment. The O NEXAFS spectra of these three aromatic compounds are very similar to other, simpler amino acids, which have been studied previously.

  15. A Novel Synthetic Pathway Enables Microbial Production of Polyphenols Independent from the Endogenous Aromatic Amino Acid Metabolism.

    Science.gov (United States)

    Kallscheuer, Nicolai; Vogt, Michael; Marienhagen, Jan

    2016-12-14

    Numerous plant polyphenols have potential applications as pharmaceuticals or nutraceuticals. Stilbenes and flavonoids as most abundant polyphenols are synthesized from phenylpropanoids, which are exclusively derived from aromatic amino acids in nature. Several microorganisms were engineered for the synthesis of biotechnologically interesting plant polyphenols; however, low activity of heterologous ammonia lyases, linking endogenous microbial aromatic amino acid biosynthesis to phenylpropanoid synthesis, turned out to be the limiting step during microbial synthesis. We here developed an alternative strategy for polyphenol production from cheap benzoic acids by reversal of a β-oxidative phenylpropanoid degradation pathway avoiding any ammonia lyase activity. The synthetic pathway running in the non-natural direction is feasible with respect to thermodynamics and involved reaction mechanisms. Instantly, product titers of 5 mg/L resveratrol could be achieved in recombinant Corynebacterium glutamicum strains indicating that phenylpropanoid synthesis from 4-hydroxybenzoic acid can in principle be implemented independently from aromatic amino acids and ammonia lyase activity.

  16. Selectivity and affinity determinants for ligand binding to the aromatic amino acid hydroxylases.

    Science.gov (United States)

    Teigen, Knut; McKinney, Jeffrey Alan; Haavik, Jan; Martínez, Aurora

    2007-01-01

    Hydroxylation of the aromatic amino acids phenylalanine, tyrosine and tryptophan is carried out by a family of non-heme iron and tetrahydrobiopterin (BH4) dependent enzymes, i.e. the aromatic amino acid hydroxylases (AAHs). The reactions catalyzed by these enzymes are important for biomedicine and their mutant forms in humans are associated with phenylketonuria (phenylalanine hydroxylase), Parkinson's disease and DOPA-responsive dystonia (tyrosine hydroxylase), and possibly neuropsychiatric and gastrointestinal disorders (tryptophan hydroxylase 1 and 2). We attempt to rationalize current knowledge about substrate and inhibitor specificity based on the three-dimensional structures of the enzymes and their complexes with substrates, cofactors and inhibitors. In addition, further insights on the selectivity and affinity determinants for ligand binding in the AAHs were obtained from molecular interaction field (MIF) analysis. We applied this computational structural approach to a rational analysis of structural differences at the active sites of the enzymes, a strategy that can help in the design of novel selective ligands for each AAH.

  17. Glyceryl ether monooxygenase resembles aromatic amino acid hydroxylases in metal ion and tetrahydrobiopterin dependence.

    Science.gov (United States)

    Watschinger, Katrin; Keller, Markus A; Hermetter, Albin; Golderer, Georg; Werner-Felmayer, Gabriele; Werner, Ernst R

    2009-01-01

    Glyceryl ether monooxygenase is a tetrahydrobiopterin-dependent membrane-bound enzyme which catalyses the cleavage of lipid ethers into glycerol and the corresponding aldehyde. Despite many different characterisation and purification attempts, so far no gene and primary sequence have been assigned to this enzyme. The seven other tetrahydrobiopterin-dependent enzymes can be divided in the family of aromatic amino acid hydroxylases - comprising phenylalanine hydroxylase, tyrosine hydroxylase and the two tryptophan hydroxylases - and into the three nitric oxide synthases. We tested the influences of different metal ions and metal ion chelators on glyceryl ether monooxygenase, phenylalanine hydroxylase and nitric oxide synthase activity to elucidate the relationship of glyceryl ether monooxygenase to these two families. 1,10-Phenanthroline, an inhibitor of non-heme iron-dependent enzymes, was able to potently block glyceryl ether monooxygenase as well as phenylalanine hydroxylase, but had no effect on inducible nitric oxide synthase. Two tetrahydrobiopterin analogues, N(5)-methyltetrahydrobiopterin and 4-aminotetrahydrobiopterin, had a similar impact on glyceryl ether monooxygenase activity, as has already been shown for phenylalanine hydroxylase. These observations point to a close analogy of the role of tetrahydrobiopterin in glyceryl ether monooxygenase and in aromatic amino acid hydroxylases and suggest that glyceryl ether monooxygenase may require a non-heme iron for catalysis.

  18. Extended Electron-Transfer in Animal Cryptochromes Mediated by a Tetrad of Aromatic Amino Acids.

    Science.gov (United States)

    Nohr, Daniel; Franz, Sophie; Rodriguez, Ryan; Paulus, Bernd; Essen, Lars-Oliver; Weber, Stefan; Schleicher, Erik

    2016-07-26

    The cryptochrome/photolyase protein family possesses a conserved triad of tryptophans that may act as a molecular wire to transport electrons from the protein surface to the FAD cofactor for activation and/or signaling-state formation. Members from the animal (and animal-like) cryptochrome subclade use this process in a light-induced fashion in a number of exciting responses, such as the (re-)setting of circadian rhythms or magnetoreception; however, electron-transfer pathways have not been explored in detail yet. Therefore, we present an in-depth time-resolved optical and electron-paramagnetic resonance spectroscopic study of two cryptochromes from Chlamydomonas reinhardtii and Drosophila melanogaster. The results do not only reveal the existence of a fourth, more distant aromatic amino acid that serves as a terminal electron donor in both proteins, but also show that a tyrosine is able to fulfill this very role in Chlamydomonas reinhardtii cryptochrome. Additionally, exchange of the respective fourth aromatic amino acid to redox-inactive phenylalanines still leads to light-induced radical pair formation; however, the lifetimes of these species are drastically reduced from the ms- to the μs-range. The results presented in this study open up a new chapter, to our knowledge, in the diversity of electron-transfer pathways in cryptochromes. Moreover, they could explain unique functions of animal cryptochromes, in particular their potential roles in magnetoreception because magnetic-field effects of light-induced radical pairs strongly depend on distance and orientation parameters.

  19. Unexpectedly Enhanced Solubility of Aromatic Amino Acids and Peptides in an Aqueous Solution of Divalent Transition-Metal Cations

    Science.gov (United States)

    Shi, Guosheng; Dang, Yaru; Pan, Tingting; Liu, Xing; Liu, Hui; Li, Shaoxian; Zhang, Lijuan; Zhao, Hongwei; Li, Shaoping; Han, Jiaguang; Tai, Renzhong; Zhu, Yiming; Li, Jichen; Ji, Qing; Mole, R. A.; Yu, Dehong; Fang, Haiping

    2016-12-01

    We experimentally observed considerable solubility of tryptophan (Trp) in a CuCl2 aqueous solution, which could reach 2-5 times the solubility of Trp in pure water. Theoretical studies show that the strong cation-π interaction between Cu2 + and the aromatic ring in Trp modifies the electronic distribution of the aromatic ring to enhance significantly the water affinity of Trp. Similar solubility enhancement has also been observed for other divalent transition-metal cations (e.g., Zn2 + and Ni2 + ), another aromatic amino acid (phenylalanine), and three aromatic peptides (Trp-Phe, Phe-Phe, and Trp-Ala-Phe).

  20. EXTRACTION OF AROMATIC AMINO ACIDS BY POLY-N-VINYLPYRROLIDONE-3500

    Directory of Open Access Journals (Sweden)

    N. Ia. Mokshina

    2014-01-01

    Full Text Available The extraction of phenylalanine, tyrosine and tryptophan from aqueous salt solutions by water soluble polymer - poly-N-vinylpyrrolidone having a molecular weight of 3,500 has been studied. Under identical conditions set quantitative characteristics extraction has been established, general scheme of analysis has been developed. Effect the volume ratio of aqueous and organic phases to the recovery of phenylalanine, tryptophan and tyrosine has been studied. The dependence of solution viscosity of the polymer and the speed of lamination systems the molecular weight and concentration of the extractant has been set. It was established that the most studied aromatic amino fully extracted solution of PVP-3500 at a concentration of 0,12 g/cm3, while the ratio of the equilibrium amounts of aqueous and organic phases 10:4. Optimized conditions for the almost complete extraction of phenylalanine, tyrosine and tryptophan from aqueous salt solutions. The technique of extraction-spectrophotometer determination of aromatic amino acids in aqueous solution. Based highs proposed scheme of interaction with PVP-3500 extractable substances. We have developed a technique characterized by express (analysis time 30 - 40 min, accuracy (relative error within 7%, ecology (and lack of toxic extragants "green extraction". Learned extraction systems applicable to practically complete extraction of phenylalanine, tyrosine and tryptophan from aqueous solutions.

  1. The role of aromatic L-amino acid decarboxylase in bacillamide C biosynthesis by Bacillus atrophaeus C89

    OpenAIRE

    Lei Yuwen; Feng-Li Zhang; Qi-Hua Chen; Shuang-Jun Lin; Yi-Lei Zhao; Zhi-Yong Li

    2013-01-01

    For biosynthesis of bacillamide C by Bacillus atrophaeus C89 associated with South China sea sponge Dysidea avara, it is hypothesized that decarboxylation from L-tryptophan to tryptamine could be performed before amidation by the downstream aromatic L-amino acid decarboxylase (AADC) to the non-ribosomal peptide synthetases (NRPS) gene cluster for biosynthesizing bacillamide C. The structural analysis of decarboxylases' known substrates in KEGG database and alignment analysis of amino acid seq...

  2. Understanding Pathway Complexity of Organic Micro/Nanofiber Growth in Hydrogen Bonded Co-Assembly of Aromatic Amino Acids.

    Science.gov (United States)

    Xing, Pengyao; Li, Peizhou; Chen, Hongzhong; Hao, Aiyou; Zhao, Yanli

    2017-04-03

    Rational engineering of one-dimensional (1D) self-assembled aggregates to produce desired materials for versatile functions remains a challenge. In this work, we report the noncovalent modulation of 1D aggregates at micro/nanoscale using a co-assembly protocol. Aromatic amino acids were employed as the model building blocks, and melamine (Mm) behaves as a modulator to form co-assembly arrays with aromatic amino acids selectively. The selective self-assembly behavior between aromatic amino acids and Mm allows distinguishing and detecting Mm and aromatic amino acids from their analogues in macroscopic and microscopic scales. Dimensions and sizes of fibrous aggregates prepared from different amino acids show two opposite pathways from pristine assemblies to co-assemblies induced by the addition of Mm. This pathway complexity could be controlled by the molecular conformation determined by α-positioned substituents. The developed hypothesis presents an excellent expansibility to other substrates, which may guide us to rationally design and screen 1D materials with different dimensions and sizes including the production of high-quality self-standing hydrogels.

  3. Asymmetric synthesis of aromatic β-amino acids using ω-transaminase: Optimizing the lipase concentration to obtain thermodynamically unstable β-keto acids.

    Science.gov (United States)

    Mathew, Sam; Jeong, Seong-Su; Chung, Taeowan; Lee, Sang-Hyeup; Yun, Hyungdon

    2016-01-01

    Synthesized aromatic β-amino acids have recently attracted considerable attention for their application as precursors in many pharmacologically relevant compounds. Previous studies on asymmetric synthesis of aromatic β-amino acids using ω-transaminases could not be done efficiently due to the instability of β-keto acids. In this study, a strategy to circumvent the instability problem of β-keto acids was utilized to generate β-amino acids efficiently via asymmetric synthesis. In this work, thermodynamically stable β-ketoesters were initially converted to β-keto acids using lipase, and the β-keto acids were subsequently aminated using ω-transaminase. By optimizing the lipase concentration, we successfully overcame the instability problem of β-keto acids and enhanced the production of β-amino acids. This strategy can be used as a general approach to efficiently generate β-amino acids from β-ketoesters.

  4. Self-assembly of short peptides composed of only aliphatic amino acids and a combination of aromatic and aliphatic amino acids.

    Science.gov (United States)

    Subbalakshmi, Chilukuri; Manorama, Sunkara V; Nagaraj, Ramakrishnan

    2012-05-01

    The morphology of structures formed by the self-assembly of short N-terminal t-butyloxycarbonyl (Boc) and C-terminal methyl ester (OMe) protected and Boc-deprotected hydrophobic peptide esters was investigated. We have observed that Boc-protected peptide esters composed of either only aliphatic hydrophobic amino acids or aliphatic hydrophobic amino acids in combination with aromatic amino acids, formed highly organized structures, when dried from methanol solutions. Transmission and scanning electron microscopic images of the peptides Boc-Ile-Ile-OMe, Boc-Phe-Phe-Phe-Ile-Ile-OMe and Boc-Trp-Ile-Ile-OMe showed nanotubular structures. Removal of the Boc group resulted in disruption of the ability to form tubular structures though spherical aggregates were formed. Both Boc-Leu-Ile-Ile-OMe and H-Leu-Ile-Ile-OMe formed only spherical nanostructures. Dynamic light scattering studies showed that aggregates of varying dimensions were present in solution suggesting that self-assembly into ordered structures is facilitated by aggregation in solution. Fourier transform infrared spectroscopy and circular dichroism spectroscopy data show that although all four of the protected peptides adopt well-defined tertiary structures, upon removal of the Boc group, only H-Phe-Phe-Phe-Ile-Ile-OMe had the ability to adopt β-structure. Our results indicate that hydrophobic interaction is a very important determinant for self-assembly and presence of charged and aromatic amino acids in a peptide is not necessary for self-assembly.

  5. Metal-organic complex-functionalized protein nanopore sensor for aromatic amino acids chiral recognition.

    Science.gov (United States)

    Guo, Yanli; Niu, Aihua; Jian, Feifei; Wang, Ying; Yao, Fujun; Wei, Yongfeng; Tian, Lei; Kang, Xiaofeng

    2017-03-27

    Chiral recognition at single-molecule level for small active molecules is important, as exhibited by many nanostructures and molecular assemblies in biological systems, but it presents a significant challenge. We report a simple and rapid sensing strategy to discriminate all enantiomers of natural aromatic amino acids (AAA) using a metal-organic complex-functionalized protein nanopore, in which a chiral recognition element and a chiral recognition valve were equipped. A trifunctional molecule, heptakis-(6-deoxy-6-amino)-β-cyclodextrin (am7βCD), was non-covalently lodged within the nanopore of an α-hemolysin (αHL) mutant, (M113R)7-αHL. Copper(ii) ion reversibly bonds to the amino group of am7βCD to form an am7βCD-Cu(II) complex, which allowed chiral recognition for each enantiomer in the mixture of AAA by distinct current signals. The Cu(II) plugging valve plays a crucial rule that holds chiral molecules in the nanocavity for a sufficient registering time. Importantly, six enantiomers of all nature AAA could be simultaneously recognized at one time. Enantiomeric excess (ee) could also be accurately detected by this approach. It should be possible to generalize this approach for sensing of other chiral molecules.

  6. Bioactive compounds derived from the yeast metabolism of aromatic amino acids during alcoholic fermentation.

    Science.gov (United States)

    Mas, Albert; Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Cerezo, Ana B; Troncoso, Ana M; Garcia-Parrilla, M Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

  7. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    Science.gov (United States)

    Guillamon, Jose Manuel; Torija, Maria Jesus; Beltran, Gemma; Troncoso, Ana M.; Garcia-Parrilla, M. Carmen

    2014-01-01

    Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements. PMID:24895623

  8. Photoionization of aromatic amino acid at different pH values

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    The photoioization of aromatic amino acid in solutions of different pH values were investigated by 248 nm laser flash photolysis. The results showed that the photoionizations of tyrosine and tryptophan were affected by pH value of solution, but phenylalanine was not. The ionization was in favor of monophotonic process at high pH value and of biphotonic process at low pH value. The mechanisms of pH effect on photoionization of tyrosine and tryptophan were the deprotonation of phenolic hydroxyl group and the deprotonation of>NH on the indole ring respectively. Our results explain the discrepancy of values for the yield of hydrated electron obtained by other investigators.

  9. The phylogeny of the aromatic amino acid hydroxylases revisited by characterizing phenylalanine hydroxylase from Dictyostelium discoideum.

    Science.gov (United States)

    Siltberg-Liberles, Jessica; Steen, Ida Helene; Svebak, Randi M; Martinez, Aurora

    2008-12-31

    The social amoeba Dictyostelium discoideum contains only one aromatic amino acid hydroxylase (AAAH) gene compared to at least three in metazoans. As shown in this work this gene codes for a phenylalanine hydroxylase (DictyoPAH) and phylogenetic analysis places this enzyme close to the precursor AAAHs, aiding to define the evolutionary history of the AAAH family. DictyoPAH shows significant similarities to other eukaryote PAH, but it exhibits higher activity with tetrahydrodictyopterin (DH4) than with tetrahydrobiopterin (BH4) as cofactor. DH4 is an abundant tetrahydropterin in D. discoideum while BH4 is the natural cofactor of the AAAHs in mammals. Moreover, DictyoPAH is devoid of the characteristic regulatory mechanisms of mammalian PAH such as positive cooperativity for L-Phe and activation by preincubation with the substrate. Analysis of the few active site substitutions between DictyoPAH and mammalian PAH, including mutant expression analysis, reveals potential structural determinants for allosteric regulation.

  10. Characterization of transient species in laser photolysis of aromatic amino acids using acetone as photosensitizer

    Institute of Scientific and Technical Information of China (English)

    宋钦华; 徐业平; 俞书勤; 陈从香; 马兴孝; 王文锋; 姚思德; 林念芸

    1999-01-01

    The photochemical processes of aromatic amino acids were investigated in aqueous solution using acetone as photosensitizer by KrF (248 nm) laser flash photolysis. Laser-induced transient species were characterized according to kinetic analysis and quenching experiments. The intermediates recorded were assigned to the excited triplet state of tryptophan, the radicals of tryptophan and tyrosine. The excited triplet state of tryptophan produced via a triplet-triplet excitation transfer and the radicals arising from electron transfer reaction has been identified. Neither electron transfer nor energy transfer between triplet acetone and phenylalanine can occur in photolysis of phenylalanine aqueous solution which contains acetone. Furthermore, triplet acetone-induced radical transformation: Trp/N-Tyr→Trp-Tyr/O was observed directly in photolysis of dipeptide (Trp-Tyr) aqueous solution containing acetone, and the transformation resulting from intramolecular electron transfer was suggested.

  11. Bioactive Compounds Derived from the Yeast Metabolism of Aromatic Amino Acids during Alcoholic Fermentation

    Directory of Open Access Journals (Sweden)

    Albert Mas

    2014-01-01

    Full Text Available Metabolites resulting from nitrogen metabolism in yeast are currently found in some fermented beverages such as wine and beer. Their study has recently attracted the attention of researchers. Some metabolites derived from aromatic amino acids are bioactive compounds that can behave as hormones or even mimic their role in humans and may also act as regulators in yeast. Although the metabolic pathways for their formation are well known, the physiological significance is still far from being understood. The understanding of this relevance will be a key element in managing the production of these compounds under controlled conditions, to offer fermented food with specific enrichment in these compounds or even to use the yeast as nutritional complements.

  12. Branched-chain and aromatic amino acid catabolism into aroma volatiles in Cucumis melo L. fruit

    Science.gov (United States)

    The unique aroma of melons (Cucumis melo L., Cucurbitaceae) is composed of many volatile compounds biosynthetically derived from fatty-acids, carotenoids, amino-acids as well as terpenes. Incubation of melon fruit cubes with amino- and a-keto acids led to the enhanced formation of aroma compounds be...

  13. The antifungal eugenol perturbs dual aromatic and branched-chain amino acid permeases in the cytoplasmic membrane of yeast.

    Science.gov (United States)

    Darvishi, Emad; Omidi, Mansoor; Bushehri, Ali Akbar Shahnejat; Golshani, Ashkan; Smith, Myron L

    2013-01-01

    Eugenol is an aromatic component of clove oil that has therapeutic potential as an antifungal drug, although its mode of action and precise cellular target(s) remain ambiguous. To address this knowledge gap, a chemical-genetic profile analysis of eugenol was done using ∼4700 haploid Saccharomyces cerevisiae gene deletion mutants to reveal 21 deletion mutants with the greatest degree of susceptibility. Cellular roles of deleted genes in the most susceptible mutants indicate that the main targets for eugenol include pathways involved in biosynthesis and transport of aromatic and branched-chain amino acids. Follow-up analyses showed inhibitory effects of eugenol on amino acid permeases in the yeast cytoplasmic membrane. Furthermore, phenotypic suppression analysis revealed that eugenol interferes with two permeases, Tat1p and Gap1p, which are both involved in dual transport of aromatic and branched-chain amino acids through the yeast cytoplasmic membrane. Perturbation of cytoplasmic permeases represents a novel antifungal target and may explain previous observations that exposure to eugenol results in leakage of cell contents. Eugenol exposure may also contribute to amino acid starvation and thus holds promise as an anticancer therapeutic drug. Finally, this study provides further evidence of the usefulness of the yeast Gene Deletion Array approach in uncovering the mode of action of natural health products.

  14. Amino acids

    Science.gov (United States)

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

  15. Deletion of the Saccharomyces cerevisiae ARO8 gene, encoding an aromatic amino acid transaminase, enhances phenylethanol production from glucose.

    Science.gov (United States)

    Romagnoli, Gabriele; Knijnenburg, Theo A; Liti, Gianni; Louis, Edward J; Pronk, Jack T; Daran, Jean-Marc

    2015-01-01

    Phenylethanol has a characteristic rose-like aroma that makes it a popular ingredient in foods, beverages and cosmetics. Microbial production of phenylethanol currently relies on whole-cell bioconversion of phenylalanine with yeasts that harbour an Ehrlich pathway for phenylalanine catabolism. Complete biosynthesis of phenylethanol from a cheap carbon source, such as glucose, provides an economically attractive alternative for phenylalanine bioconversion. In this study, synthetic genetic array (SGA) screening was applied to identify genes involved in regulation of phenylethanol synthesis in Saccharomyces cerevisiae. The screen focused on transcriptional regulation of ARO10, which encodes the major decarboxylase involved in conversion of phenylpyruvate to phenylethanol. A deletion in ARO8, which encodes an aromatic amino acid transaminase, was found to underlie the transcriptional upregulation of ARO10 during growth, with ammonium sulphate as the sole nitrogen source. Physiological characterization revealed that the aro8Δ mutation led to substantial changes in the absolute and relative intracellular concentrations of amino acids. Moreover, deletion of ARO8 led to de novo production of phenylethanol during growth on a glucose synthetic medium with ammonium as the sole nitrogen source. The aro8Δ mutation also stimulated phenylethanol production when combined with other, previously documented, mutations that deregulate aromatic amino acid biosynthesis in S. cerevisiae. The resulting engineered S. cerevisiae strain produced >3 mm phenylethanol from glucose during growth on a simple synthetic medium. The strong impact of a transaminase deletion on intracellular amino acid concentrations opens new possibilities for yeast-based production of amino acid-derived products.

  16. Induction of aromatic-L-amino acid decarboxylase by decarboxylase inhibitors in idiopathic parkinsonism.

    Science.gov (United States)

    Boomsma, F; Meerwaldt, J D; Man in 't Veld, A J; Hovestadt, A; Schalekamp, M A

    1989-06-01

    We evaluated the effect of administration of L-dopa, alone or in combination with a peripheral decarboxylase inhibitor, on plasma levels of aromatic-L-amino acid decarboxylase (ALAAD). After single-dose administration of L-dopa plus benserazide (Madopar) in healthy subjects and in chronically treated patients with parkinsonism, plasma ALAAD followed for 2 to 3 hours fell, but returned to predosing levels within 90 minutes. Four groups of patients with idiopathic parkinsonism were studied during chronic treatment: Group I, no L-dopa treatment (n = 31); Group II, L-dopa alone (n = 15); Group III, L-dopa plus benserazide (n = 28); and Group IV, L-dopa plus carbidopa (Sinemet, n = 30). Plasma ALAAD 2 hours after dosing was normal in Groups I and II. ALAAD was increased threefold in Groups III and IV, suggesting induction of ALAAD by the coadministration of a peripheral decarboxylase inhibitor. In a study of 3 patients in whom L-dopa/benserazide was started, plasma ALAAD rose gradually over 3 to 4 weeks. Further detailed pharmacokinetic studies of L-dopa, dopamine, and ALAAD in plasma and cerebrospinal fluid are required to determine if the apparent ALAAD induction by a peripheral decarboxylase inhibitor may be related to the loss of clinical efficacy of combination therapy in some patients and how it is related to end-of-dose deterioration and on-off phenomena.

  17. Aromatic L-amino acid decarboxylase deficiency diagnosed by clinical metabolomic profiling of plasma.

    Science.gov (United States)

    Atwal, Paldeep S; Donti, Taraka R; Cardon, Aaron L; Bacino, C A; Sun, Qin; Emrick, L; Reid Sutton, V; Elsea, Sarah H

    2015-01-01

    Aromatic L-amino acid decarboxylase (AADC) deficiency is an inborn error of metabolism affecting the biosynthesis of serotonin, dopamine, and catecholamines. We report a case of AADC deficiency that was detected using the Global MAPS platform. This is a novel platform that allows for parallel clinical testing of hundreds of metabolites in a single plasma specimen. It uses a state-of-the-art mass spectrometry platform, and the resulting spectra are compared against a library of ~2500 metabolites. Our patient is now a 4 year old boy initially seen at 11 months of age for developmental delay and hypotonia. Multiple tests had not yielded a diagnosis until exome sequencing revealed compound heterozygous variants of uncertain significance (VUS), c.286G>A (p.G96R) and c.260C>T (p.P87L) in the DDC gene, causal for AADC deficiency. CSF neurotransmitter analysis confirmed the diagnosis with elevated 3-methoxytyrosine (3-O-methyldopa). Metabolomic profiling was performed on plasma and revealed marked elevation in 3-methoxytyrosine (Z-score +6.1) consistent with the diagnosis of AADC deficiency. These results demonstrate that the Global MAPS platform is able to diagnose AADC deficiency from plasma. In summary, we report a novel and less invasive approach to diagnose AADC deficiency using plasma metabolomic profiling.

  18. Characterization of π-stacking interactions between aromatic amino acids and quercetagetin

    Science.gov (United States)

    Akher, Farideh Badichi; Ebrahimi, Ali; Mostafavi, Najmeh

    2017-01-01

    In the present study, the π-stacking interactions between quercetagetin (QUE), which is one of the most representative flavonol compounds with biological and chemical activities, and some aromatic amino acid (AA) residues has been investigated by the quantum mechanical calculations. The trend in the absolute value of stacking interaction energy |ΔE| with respect to AAs is HIS > PHE > TYR > TPR. The results show that the sum of donor-acceptor interaction energy between AAs and QUE (∑E2) and the sum of electron densities ρ calculated at BCPs and CCPs between the rings (∑ρBCPs and ∑ρCCP) can be useful descriptors for prediction of the ΔE values of the complexes. The Osbnd H bond dissociation enthalpy (BDE) slightly decreases by the π-stacking interaction, which confirms the positive effect of that interaction on the antioxidant activity of QUE. A reverse trend is observed for BDE when is compared with the |ΔE| values. A reliable relationship is also observed between the Muliken spin density (MSD) distributions of the radical species and the most convenient Osbnd H bond dissociations. In addition, reactivity is in good correlation with the antioxidant activity of the complexes.

  19. An amino acid at position 142 in nitrilase from Rhodococcus rhodochrous ATCC 33278 determines the substrate specificity for aliphatic and aromatic nitriles.

    Science.gov (United States)

    Yeom, Soo-Jin; Kim, Hye-Jung; Lee, Jung-Kul; Kim, Dong-Eun; Oh, Deok-Kun

    2008-11-01

    Nitrilase from Rhodococcus rhodochrous ATCC 33278 hydrolyses both aliphatic and aromatic nitriles. Replacing Tyr-142 in the wild-type enzyme with the aromatic amino acid phenylalanine did not alter specificity for either substrate. However, the mutants containing non-polar aliphatic amino acids (alanine, valine and leucine) at position 142 were specific only for aromatic substrates such as benzonitrile, m-tolunitrile and 2-cyanopyridine, and not for aliphatic substrates. These results suggest that the hydrolysis of substrates probably involves the conjugated pi-electron system of the aromatic ring of substrate or Tyr-142 as an electron acceptor. Moreover, the mutants containing charged amino acids such as aspartate, glutamate, arginine and asparagine at position 142 displayed no activity towards any nitrile, possibly owing to the disruption of hydrophobic interactions with substrates. Thus aromaticity of substrate or amino acid at position 142 in R. rhodochrous nitrilase is required for enzyme activity.

  20. Self-assembly of aromatic α-amino acids into amyloid inspired nano/micro scaled architects.

    Science.gov (United States)

    Singh, Prabhjot; Brar, Surinder K; Bajaj, Manish; Narang, Nikesh; Mithu, Venus S; Katare, Om P; Wangoo, Nishima; Sharma, Rohit K

    2017-03-01

    In the pursuit for design of novel bio inspired materials, aromatic α-amino acids (phenylalanine, tyrosine, tryptophan and histidine) have been investigated for the generation of well-ordered self-assembled architects such as fibrils, rods, ribbons and twisted nanosheets in varying solvent systems. These nano/micro scaled architects were thoroughly characterized using FE-SEM, confocal microscopy, optical microscopy, (1)H NMR, FTIR, XRD and TGA. These self-assembled architects were histologically stained with Congo red and thioflavin T dyes for investigation of amyloid morphology which revealed that the deposited state of ordered assemblies exhibit specific characteristic of amyloid deposits. The self-assembly of aromatic amino acids was observed to be driven by non-covalent forces such as π-π stacking, van der Waals and electrostatic interaction.

  1. Aromatic Amino Acid Decarboxylase Deficiency Not Responding to Pyridoxine and Bromocriptine Therapy: Case Report and Review of Response to Treatment

    OpenAIRE

    2014-01-01

    Aromatic L-amino acid decarboxylase (AADC) deficiency (MIM #608643) is an autosomal recessive inborn error of monoamines. It is caused by a mutation in the DDC gene that leads to a deficiency in the AADC enzyme. The clinical features of this condition include a combination of dopamine, noradrenaline, and serotonin deficiencies, and a patient may present with hypotonia, oculogyric crises, sweating, hypersalivation, autonomic dysfunction, and progressive encephalopathy with severe developmental...

  2. Decreased serum essential and aromatic amino acids in patients with chronic pancreatitis

    Institute of Scientific and Technical Information of China (English)

    Krystian; Adrych; Marian; Smoczynski; Magdalena; Stojek; Tomasz; Sledzinski; Ewa; Slominska; Elzbieta; Goyke; Ryszard; Tomasz; Smolenski; Julian; Swierczynski

    2010-01-01

    AIM:To investigate the influence of chronic pancreatitis(CP) on serum concentrations of amino acids.METHODS:Thirty-five male patients with alcoholic CP and 21 healthy male subjects were examined.Serum concentrations of amino acids were assayed by ionpair high-performance liquid chromatography with mass detection.RESULTS:Serum glutamate concentration was increased in CP patients as compared to controls.In contrast,serum concentrations of glutamine,histidine,tyrosine,proline,tryptophan and threonine were sign...

  3. Establishment of a yeast platform strain for production of p-coumaric acid through metabolic engineering of aromatic amino acid biosynthesis

    DEFF Research Database (Denmark)

    Rodriguez Prado, Edith Angelica; Kildegaard, Kanchana Rueksomtawin; Li, Mingji;

    2015-01-01

    Aromatic amino acids are precursors of numerous plant secondary metabolites with diverse biological functions. Many of these secondary metabolites are already being used as active pharmaceutical or nutraceutical ingredients, and there are numerous exploratory studies of other compounds...... with promising applications. p-Coumaric acid is derived from aromatic amino acids and, besides being a valuable chemical building block, it serves as precursor for biosynthesis of many secondary metabolites, such as polyphenols, flavonoids, and some polyketides. Here we developed a p-coumaric acid...... was obtained, when overexpressing tyrosine ammonia-lyase TAL from Flavobacterium johnsoniaeu, DAHP synthase ARO4K229L, chorismate mutase ARO7G141S and E. coli shikimate kinase II (aroL) in Δpdc5Δaro10 strain background. To our knowledge this is the highest reported titer of an aromatic compound produced...

  4. Functional characterization of aromatic amino acid aminotransferase involved in 2-phenylethanol biosynthesis in isolated rose petal protoplasts.

    Science.gov (United States)

    Hirata, Hiroshi; Ohnishi, Toshiyuki; Ishida, Haruka; Tomida, Kensuke; Sakai, Miwa; Hara, Masakazu; Watanabe, Naoharu

    2012-03-15

    In rose flowers, 2-phenylethanol (2PE) is biosynthesized from l-phenylalanine (l-Phe) via phenylacetaldehyde (PAld) by the actions of two enzymes, pyridoxal-5'-phosphate (PLP)-dependent aromatic amino acid decarboxylase (AADC) and phenylacetaldehyde reductase (PAR). We here report that Rosa 'Yves Piaget' aromatic amino acid aminotransferase produced phenylpyruvic acid (PPA) from l-Phe in isolated petal protoplasts. We have cloned three full length cDNAs (RyAAAT1-3) of aromatic amino acid aminotransferase families based on rose EST database and homology regions. The RyAAATs enzymes were heterogeneously expressed in Escherichia coli and characterized biochemically. The recombinant RyAAAT3 showed the highest activity toward l-Phe in comparison with l-tryptophan, l-tyrosine, d-Phe, glycine, and l-alanine, and showed 9.7-fold higher activity with l-Phe rather than PPA as a substrate. RyAAAT3 had an optimal activity at pH 9 and at 45-55°C with α-ketoglutaric acid, and was found to be a PLP dependent enzyme based on the inhibition test using Carbidopa, an inhibitor of PLP-dependent enzymes. The transcript of RyAAAT3 was expressed in flowers as well as other organs of R. 'Yves Piaget'. RNAi suppression of RyAAAT3 decreased 2PE production, revealing the involvement of RyAAAT3 in 2PE biosynthesis in rose protoplasts and indicating that rose protoplasts have potentially two different 2PE biosynthetic pathways, the AADC route and the new route via PPA from l-Phe.

  5. Vibrational analysis of amino acids and short peptides in hydrated media. VIII. Amino acids with aromatic side chains: L-phenylalanine, L-tyrosine, and L-tryptophan.

    Science.gov (United States)

    Hernández, Belén; Pflüger, Fernando; Adenier, Alain; Kruglik, Sergei G; Ghomi, Mahmoud

    2010-11-25

    Four out of the 20 natural α-amino acids (α-AAs) contain aromatic rings in their side chains. In a recent paper (J. Phys. Chem. B 2010, 114, 9072-9083), we have analyzed the structural and vibrational features of l-histidine, one of the potent elements of this series. Here, we report on the three remaining members of this family, i.e., l-phenylalanine, l-tyrosine, and l-tryptophan. Their solution (H(2)O and D(2)O) Raman scattering and Fourier transform infrared absorption attenuated total reflection (FT-IR ATR) spectra were measured at room temperature from the species corresponding to those existing at physiological conditions. Because of the very low water solubility of tyrosine, special attention was paid to avoid any artifact concerning the report of the vibrational spectra corresponding to nondissolved powder of this AA in aqueous solution. Finally, we could obtain for the first time the Raman and FT-IR spectra of tyrosine at very low concentration (2.3 mM) upon long accumulation time. To clarify this point, those vibrational spectra of tyrosine recorded either in the solid phase or in a heterogeneous state, where dissolved and nondissolved species of this AA coexist in aqueous solution, are also provided as Supporting Information . To carry out a discussion on the general geometrical and vibrational behavior of these AAs, we resorted to quantum mechanical calculations at the DFT/B3LYP/6-31++G* level, allowing (i) determination of potential energy surfaces of these AAs in a continuum solvent as a function of the torsion angles χ(1) and χ(2), defining the conformation of each aromatic side chain around C(α)-C(β) and C(β)-C(γ) bonds, respectively; (ii) analysis of geometrical features of the AAs surrounded by clusters of n explicit (n = 5-7) water molecules interacting with the backbone and aromatic rings; and (iii) assignment of the observed vibrational modes by means of the theoretical data provided by the lowest energy conformers of explicitly

  6. A theoretical study on the interaction of aromatic amino acids with graphene and single walled carbon nanotube

    Science.gov (United States)

    Rajesh, Chinagandham; Majumder, Chiranjib; Mizuseki, Hiroshi; Kawazoe, Yoshiyuki

    2009-03-01

    In this study we have investigated the interaction of phenylalanine (Phe), histidine (His), tyrosine (Tyr), and tryptophan (Tryp) molecules with graphene and single walled carbon nanotubes (CNTs) with an aim to understand the effect of curvature on the non-covalent interaction. The calculations are performed using density functional theory and the Møller-Plesset second-order perturbation theory (MP2) within linear combination of atomic orbitals-molecular orbital (LCAO-MO) approach. Using these methods, the equilibrium configurations of these complexes were found to be very similar, i.e., the aromatic rings of the amino acids prefer to orient in parallel with respect to the plane of the substrates, which bears the signature of weak π-π interactions. The binding strength follows the trend: Hisaromatic motifs of the amino acids. Remarkably, we find excellent correlation between the polarizability and the strength of the interaction; the higher the polarizability, greater is the binding strength. Moreover, we have analyzed the electronic densities of state spectrum before and after adsorption of the amino acid moieties. The results reveal that the Fermi level of the free CNT is red-shifted by the adsorption of the amino acids and the degree of shift is consistent with the trend in polarizability of these molecules.

  7. NCA nucleophilic radiofluorination on substituted benzaldehydes for the preparation of [18F]fluorinated aromatic amino acids

    Energy Technology Data Exchange (ETDEWEB)

    Wadsak, Wolfgang [Department of Nuclear Medicine, Medical University of Vienna (Austria)]. E-mail: wolfgang.wadsak@meduniwien.ac.at; Wirl-Sagadin, Barbara [Department of Nuclear Medicine, Medical University of Vienna (Austria); Department of Inorganic Chemistry, University of Vienna (Austria); Mitterhauser, Markus [Department of Nuclear Medicine, Medical University of Vienna (Austria); Department of Pharmaceutical Technology and Biopharmaceuticals, University of Vienna (Austria); Hospital Pharmacy of the General Hospital of Vienna (Austria); Mien, Leonhard-Key [Department of Nuclear Medicine, Medical University of Vienna (Austria); Department of Pharmaceutical Technology and Biopharmaceuticals, University of Vienna (Austria); Department of Psychiatry, Medical University of Vienna (Austria); Ettlinger, Dagmar E. [Department of Nuclear Medicine, Medical University of Vienna (Austria); Keppler, Bernhard K. [Department of Inorganic Chemistry, University of Vienna (Austria); Dudczak, Robert [Department of Nuclear Medicine, Medical University of Vienna (Austria); Kletter, Kurt [Department of Nuclear Medicine, Medical University of Vienna (Austria)

    2006-03-15

    Nucleophilic aromatic substitution is a challenging task in radiochemistry. Therefore, a thorough evaluation and optimisation of this step is needed to provide a satisfactory tool for the routine preparation of [{sup 18}F]fluorinated aromatic amino acids. Two methods, already proposed elsewhere, were evaluated and improved. The yields for the radiofluorination were increased whereas activity loss during solid phase extraction was observed. Radiochemical yields for the two methods were 92.7{+-}5.5% (method 1) and 92.1{+-}12.3% (method 2) for conversion and 11.1{+-}2.8% (method 1) and 34.8{+-}0.6% (method 2) for purification, respectively. In total, we demonstrate an optimised method for the preparation of this important class of [{sup 18}F]fluorinated synthons for PET.

  8. Polycyclic aromatic hydrocarbons and amino acids in meteorites and ice samples from LaPaz Icefield, Antarctica

    Science.gov (United States)

    Botta, O.; Martins, Z.; Emmenegger, C.; Dworkin, J. P.; Glavin, D. P.; Harvey, R. P.; Zenobi, R.; Bada, J. L.; Ehrenfreund, P.

    2008-11-01

    We have analyzed ice samples and meteorites from the LaPaz region of Antarctica to investigate the composition of polycyclic aromatic hydrocarbons (PAHs) and amino acids with the goal to understand whether or not there is a compositional relationship between the two reservoirs. Four LL5 ordinary chondrites (OCs) and one CK carbonaceous chondrite were collected as part of the 2003/2004 ANSMET season. Ice samples collected from directly underneath the meteorites were extracted. In addition, exhaust particles from the snowmobiles used during the expedition were collected to investigate possible contributions from this source. The meteorite samples, the particulate matter and solid-state extracts of the ice samples and the exhaust filters were subjected to two-step laser mass spectrometry (L2MS) to investigate the PAH composition. For amino acids analysis, the meteorites were extracted with water and acid hydrolyzed, and the extracts were analyzed with offline OPA/NAC derivatization combined with liquid chromatography with UV fluorescence detection and time of flight mass spectrometry (LC-FD/ToF-MS). PAHs in the particulate matter of the ice were found to be qualitatively similar to the meteorite samples, indicating that micron-sized grains of the meteorite may be embedded in the ice samples. The concentration levels of dissolved PAHs in all the ice samples were found to be below the detection limit of the L2MS. The PAH composition of the snowmobile exhaust is significantly different to the one in particulate matter, making it an unlikely source of contamination for Antarctic meteorites. The amino acids glycine, β-alanine and γ-amino-n-butyric acid that were detected at concentrations of 3 to 19 parts per billion (ppb) are probably indigenous to the Antarctic meteorites. Some of the LaPaz ice samples were also found to contain amino acids at concentration levels of 1 to 33 parts per trillion (ppt), in particular α-aminoisobutyric acid (AIB), an abundant non

  9. A role for plasma aromatic amino acids in injurious pecking behavior in laying hens.

    Science.gov (United States)

    Birkl, Patrick; Franke, Leonora; Bas Rodenburg, T; Ellen, Ester; Harlander-Matauschek, Alexandra

    2017-03-29

    Injurious pecking, including feather pecking (FP), is one of the most prevalent causes of mortality for commercial laying hens. The underlying biological mechanisms of FP are not yet fully understood, but they could be related to alterations in the serotonin (5-HT) and/or dopamine (DA) circuits within the brain. In the past, the central synthesis of 5-HT and DA was found to be influenced by the availability of their precursors, aromatic amino acids (AAA) such as tryptophan (TRP), phenylalanine (PHE), and tyrosine (TYR), in blood plasma, which are transported across the blood-brain-barrier into the brain. Because knowledge about plasma levels of AAA in laying hens is very limited, the present study compared the AAA profiles of a large sample of laying hens from two genetic lines: one selected for low mortality (LM) due to injurious pecking (n=129 birds) and one high production line (HP) selected for high egg-production only (n=132 birds). Head, comb, and feather covering were scored at the end of the experiment. Blood samples were collected at weeks 24 and 29 of age and were analysed for AAA using high performance liquid chromatography. Neither FP nor feather damage was observed in the present study, but aggressive pecking directed at the head/neck area occurred in several groups with an onset of this aberrant behavior between weeks 22 and 29. Eight HP pens and seven LM pens were affected by severe head/comb injuries inflicted via aggressive pecking. Therefore, our exploratory data analysis focused upon the possible interplay between the variability of our outcome measures (absolute levels of AAA in plasma as well as the ratios PHE/TYR and TRP/(PHE+TYR) and the aggressive head/comb pecking as an expression of social stress within the pens. We found significantly lower TRP availability relative to PHE and TYR (TRP/(PHE+TYR) ratio) and higher TYR concentrations at week 24 in pens with an early onset of injurious aggressive behavior at weeks 22-23. This was most

  10. Spinal cord hemisection facilitates aromatic L-amino acid decarboxylase cells to produce serotonin in the subchronic but not the chronic phase

    DEFF Research Database (Denmark)

    Azam, Bushra; Wienecke, Jacob; Jensen, Dennis Bo

    2015-01-01

    Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce...

  11. Effect of thenardite on the direct detection of aromatic amino acids: implications for the search for life in the solar system

    Science.gov (United States)

    Doc Richardson, C.; Hinman, Nancy W.; Scott, Jill R.

    2009-10-01

    With the discovery of Na-sulphate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization in conjunction with a Fourier transform ion cyclotron resonance mass spectrometry. This technique is based on the ability of a mineral host to facilitate desorption and ionization of bio/organic molecules for detection. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali ion affinity of their aromatic side chains. In addition, substitution of the carboxyl group hydrogen by sodium led to formation of [M-H+Na]Na+ peaks. In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ attachment. Understanding how co-deposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

  12. Effect of Thenardite on the Direct Detection of Aromatic Amino Acids: Implications for the Search for Life in the Solar System

    Energy Technology Data Exchange (ETDEWEB)

    C. Doc Richardson; Nancy W. Hinman; Jill R. Scott

    2009-10-01

    With the discovery of Na-sulfate minerals on Mars and Europa, recent studies using these minerals have focused on their ability to assist in the detection of bio/organic signatures. This study further investigates the ability of thenardite (Na2SO4) to effectively facilitate the ionization and identification of aromatic amino acids (phenylalanine, tyrosine, and tryptophan) using a technique called geomatrix-assisted laser desorption/ionization (GALDI) in conjunction with a Fourier transform mass spectrometry (FTICR-MS). This technique is based on the ability of a mineral host to facilitate the ionization and detection of bio/organic molecules. Spectra obtained from each aromatic amino acid alone and in combination with thenardite show differences in ionization mechanism and fragmentation patterns. These differences are due to chemical and structural differences between the aromatic side chains of their respective amino acid. Tyrosine and tryptophan when combined with thenardite were observed to undergo cation-attachment ([M+Na]+), due to the high alkali affinity of their aromatic side chains. Subsequent cation substitution of the carboxyl group led to formation double cation-attached peaks ([M-H+Na]Na+). In contrast, phenylalanine mixed with thenardite showed no evidence of Na+ interaction. Understanding how codeposition of amino acids with thenardite can affect the observed mass spectra is important for future exploration missions that are likely to use laser desorption mass spectrometry to search for bio/organic compounds in extraterrestrial environments.

  13. TyrR, the regulator of aromatic amino acid metabolism, is required for mice infection of Yersinia pestis

    Directory of Open Access Journals (Sweden)

    Zhongliang eDeng

    2015-02-01

    Full Text Available Yersinia pestis, the causative agent of plague, poses a serious health threat to rodents and human beings. TyrR is a transcriptional regulator that controls the metabolism of aromatic amino acids in Escherichia coli. In this paper, TyrR played an important role in Y. pestis virulence. Inactivation of tyrR did not seem to affect the in vitro growth of this organism, but resulted in at least 10,000-fold attenuation compared with the wild-type (WT strain upon subcutaneous infection to mice. In addition, loads of tyrR mutant within mice livers and spleens significantly decreased compared with the WT strain. Transcriptome analysis revealed that TyrR, directly or indirectly, regulated 29 genes encoded on Y. pestis chromosome or plasmids under in vitro growth condition. Similar to the regulatory function of this protein in E. coli, five aromatic-pathway genes (aroF-tyrA, aroP, aroL, and tyrP were significantly reduced upon deletion of the tyrR gene. Two genes (glnL and glnG that encode sensory histidine kinase and regulator in a two-component regulatory system involved in nitrogen assimilation were downregulated in the tyrR mutant. Several genes encoding type III secretion proteins were transcribed by 2.0- to 4.2-fold in a tyrR mutant relative to the WT strain. Interestingly, the acid-stressed genes, hdeB and hdeD, were downregulated, and such downregulation partly accounted for the decrease in tolerance of the tyrR mutant under acidic conditions. In conclusion, regulation of TyrR in Y. pestis is similar to, but distinct from, that in E. coli. TyrR is a metabolic virulence determinant in Y. pestis that is important for extracellular survival and/or proliferation.

  14. High levels of aromatic amino acids in gastric juice during the early stages of gastric cancer progression.

    Directory of Open Access Journals (Sweden)

    Kai Deng

    Full Text Available BACKGROUND: Early-stage gastric cancer is mostly asymptomatic and can easily be missed easily by conventional gastroscopy. Currently, there are no useful biomarkers for the early detection of gastric cancer, and their identification of biomarkers is urgently needed. METHODS: Gastric juice was obtained from 185 subjects that were divided into three groups: non-neoplastic gastric disease (NGD, advanced gastric cancer and early gastric cancer (EGC. The levels of aromatic amino acids in the gastric juice were quantitated using high-performance liquid chromatography. RESULTS: The median values (25th to 75th percentile of tyrosine, phenylalanine and tryptophan in the gastric juice were 3.8 (1.7-7.5 µg/ml, 5.3 (2.3-9.9 µg/ml and 1.0 (0.4-2.8 µg/ml in NGD; 19.4 (5.8-72.4 µg/ml, 24.6 (11.5-73.7 µg/ml and 8.3 (2.1-28.0 µg/ml in EGC. Higher levels of tyrosine, phenylalanine and tryptophan in the gastric juice were observed in individuals of EGC groups compared those of the NGD group (NGD vs. EGC, P<0.0001. For the detection of EGC, the areas under the receiver operating characteristic curves (AUCs of each biomarker were as follows: tyrosine, 0.790 [95% confidence interval (CI, 0.703-0.877]; phenylalanine, 0.831 (95% CI, 0.750-0.911; and tryptophan, 0.819 (95% CI, 0.739-0.900. The sensitivity and specificity of phenylalanine were 75.5% and 81.4%, respectively, for detection of EGC. A multiple logistic regression analysis showed that high levels of aromatic amino acids in the gastric juice were associated with gastric cancer (adjusted β coefficients ranged from 1.801 to 4.414, P<0.001. CONCLUSION: Increased levels of tyrosine, phenylalanine and tryptophan in the gastric juice samples were detected in the early phase of gastric carcinogenesis. Thus, tyrosine, phenylalanine and tryptophan in gastric juice could be used as biomarkers for the early detection of gastric cancer. A gastric juice analysis is an efficient, economical and convenient method for

  15. Characterization of novel perylene diimides containing aromatic amino acid side chains

    Science.gov (United States)

    Farooqi, Mohammed J.; Penick, Mark A.; Burch, Jessica; Negrete, George R.; Brancaleon, Lorenzo

    2016-01-01

    Perylene diimide derivatives have attracted initial interest as industrial dyes. Recently, much attention has been focused on their strong π- π stacks resulting from the large PDI aromatic core. These PDI stacks have distinct optical properties, and provide informative models that could mimic light-harvesting systems and initial charge transfer typical of photosynthetic systems. The absorption property of PDI derivatives may be tuned from visible to near-infrared region by peripheral substitution. We have studied a new class of PDI derivatives with aryl substituents derived from the side chains of aromatic aminoacids (Tyrosine, Tryptophan and Phenylalanine). We have investigated their absorption and the fluorescence properties in a set of organic solvents and established their different tendencies to aggregate in solution despite their solubility. Most aggregation appears to be unordered. One PDI analogue (the one formed from Tyr) in Methanol, however, appears to form J-type aggregates. Based on our results the compounds appear to be promising for future investigations regarding the interaction of these dyes with biomolecules.

  16. Aromatic amino acids providing characteristic motifs in the Raman and SERS spectroscopy of peptides.

    Science.gov (United States)

    Wei, Fang; Zhang, Dongmao; Halas, Naomi J; Hartgerink, Jeffrey D

    2008-07-31

    Raman and surface-enhanced Raman spectroscopies (SERS) are potentially important tools in the characterization of biomolecules such as proteins and DNA. In this work, SERS spectra of three cysteine-containing aromatic peptides: tryptophan-cysteine, tyrosine-cysteine, and phenylalanine-cysteine, bound to Au nanoshell substrates, were obtained, and compared to their respective normal Raman spectra. While the linewidths of the SERS peaks are significantly broadened (up to 70%), no significant spectral shifts (features in the Raman and SERS spectra of peptides and proteins when present. It follows that the Raman modes of these three small constructed peptides may likely apply to the assignment of Raman and SERS features in the spectra of other peptides and proteins.

  17. Transcriptome profiling and physiological studies reveal a major role for aromatic amino acids in mercury stress tolerance in rice seedlings.

    Directory of Open Access Journals (Sweden)

    Yun-An Chen

    Full Text Available Mercury (Hg is a serious environmental pollution threat to the planet. The accumulation of Hg in plants disrupts many cellular-level functions and inhibits growth and development, but the mechanism is not fully understood. To gain more insight into the cellular response to Hg, we performed a large-scale analysis of the rice transcriptome during Hg stress. Genes induced with short-term exposure represented functional categories of cell-wall formation, chemical detoxification, secondary metabolism, signal transduction and abiotic stress response. Moreover, Hg stress upregulated several genes involved in aromatic amino acids (Phe and Trp and increased the level of free Phe and Trp content. Exogenous application of Phe and Trp to rice roots enhanced tolerance to Hg and effectively reduced Hg-induced production of reactive oxygen species. Hg induced calcium accumulation and activated mitogen-activated protein kinase. Further characterization of the Hg-responsive genes we identified may be helpful for better understanding the mechanisms of Hg in plants.

  18. A promoter melting region in the primary sigma factor of Bacillus subtilis. Identification of functionally important aromatic amino acids.

    Science.gov (United States)

    Juang, Y L; Helmann, J D

    1994-02-04

    Sigma factor (sigma) is a dissociable subunit of bacterial RNA polymerase that determines promoter recognition. It has been proposed that a cluster of highly conserved aromatic amino acids in bacterial sigma factors (region 2.3) defines a melting motif that functions in strand-separation during open complex formation. We demonstrate that many alterations in region 2.3 of the Bacillus subtilis sigma A protein specifically impair open complex formation. The region 2.3 mutations can be grouped in three classes: (1) mutations that do not significantly affect promoter recognition or melting; (2) mutations that lead to cold-sensitive transcription of linear templates; and (3) mutations that lead to little activity on linear templates but retain activity at high temperatures on supercoiled templates. RNA polymerase holoenzymes containing sigma factor melting mutants (classes 2 and 3) form predominantly closed complexes at 40 degrees C and are defective for RNA synthesis when initiation is rate-limiting. The melting defect of these mutant sigma factors is suppressed by template supercoiling, but further enhanced by inclusion of the auxiliary RNA polymerase subunit delta. Consequently, in the presence of the delta polypeptide, the mutant holoenzymes display cold-sensitive transcription on supercoiled templates: conditions which mimic the in vivo situation. A subset of these mutations also affects promoter selectivity, suggesting that region 2.3 may participate in both -10 recognition and DNA melting.

  19. 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 ...

  20. Rapid and precise measurement of serum branched-chain and aromatic amino acids by isotope dilution liquid chromatography tandem mass spectrometry.

    Directory of Open Access Journals (Sweden)

    Ruiyue Yang

    Full Text Available BACKGROUND: Serum branched-chain and aromatic amino acids (BCAAs and AAAs have emerged as predictors for the future development of diabetes and may aid in diabetes risk assessment. However, the current methods for the analysis of such amino acids in biological samples are time consuming. METHODS: An isotope dilution liquid chromatography tandem mass spectrometry (ID-LC/MS/MS method for serum BCAAs and AAAs was developed. The serum was mixed with isotope-labeled BCAA and AAA internal standards and the amino acids were extracted with acetonitrile, followed by analysis using LC/MS/MS. The LC separation was performed on a reversed-phase C18 column, and the MS/MS detection was performed via the positive electronic spray ionization in multiple reaction monitoring mode. RESULTS: Specific analysis of the amino acids was achieved within 2 min. Intra-run and total CVs for the amino acids were less than 2% and 4%, respectively, and the analytical recoveries ranged from 99.6 to 103.6%. CONCLUSION: A rapid and precise method for the measurement of serum BCAAs and AAAs was developed and may serve as a quick tool for screening serum BCAAs and AAAs in studies assessing diabetes risk.

  1. Predicting the side-chain dihedral angle distributions of nonpolar, aromatic, and polar amino acids using hard sphere models.

    Science.gov (United States)

    Zhou, Alice Qinhua; O'Hern, Corey S; Regan, Lynne

    2014-10-01

    The side-chain dihedral angle distributions of all amino acids have been measured from myriad high-resolution protein crystal structures. However, we do not yet know the dominant interactions that determine these distributions. Here, we explore to what extent the defining features of the side-chain dihedral angle distributions of different amino acids can be captured by a simple physical model. We find that a hard-sphere model for a dipeptide mimetic that includes only steric interactions plus stereochemical constraints is able to recapitulate the key features of the back-bone dependent observed amino acid side-chain dihedral angle distributions of Ser, Cys, Thr, Val, Ile, Leu, Phe, Tyr, and Trp. We find that for certain amino acids, performing the calculations with the amino acid of interest in the central position of a short α-helical segment improves the match between the predicted and observed distributions. We also identify the atomic interactions that give rise to the differences between the predicted distributions for the hard-sphere model of the dipeptide and that of the α-helical segment. Finally, we point out a case where the hard-sphere plus stereochemical constraint model is insufficient to recapitulate the observed side-chain dihedral angle distribution, namely the distribution P(χ₃) for Met.

  2. Computer-aided discovery of aromatic L-α-amino acids as agonists of the orphan G protein-coupled receptor GPR139

    DEFF Research Database (Denmark)

    Ísberg, Vignir; Andersen, Kirsten Bayer; Bisig, Christoph;

    2014-01-01

    GPR139 is an orphan G protein-coupled receptor expressed mainly in the central nervous system. We developed a pharmacophore model based on known GPR139 surrogate agonists which led us to propose aromatic-containing dipeptides as potential ligands. Upon testing, the dipeptides demonstrated agonism...... in the Gq pathway. Next, testing all 20 proteinogenic L-α-amino acids; L-tryptophan and L-phenylalanine were found to have EC50 values of 220 µM and 320 µM, respectively, making them the first putative endogenous agonists for GPR139....

  3. ESI/MS of N-(O, O-Diisopropyl) Phosphoryl Aromatic Amino Acids and their Stability Investigation Using HPLC/UV/ESI/MS

    Institute of Scientific and Technical Information of China (English)

    Hong Xia LIU; Shu Sheng ZHANG; Jian Chen ZHANG; Xiao YANG; Ling Bo QU; Yu Fen ZHAO

    2005-01-01

    The full scan ESI/MS and ESI/MS2 of N-(O, O-diisopropyl) phosphoryl aromatic amino acids (DIPPAAAs), N-(O, O-diisopropyl) phosphoryl phenylalanine, N-(O, O-diisopropyl)phosphoryl tryptophan and N-(O, O-diisopropyl) phosphoryl tyrosine, were obtained. The specific ions for them were found. Their stability in the LC mobile phase was investigated using developed HPLC/UV/ESI/MS and the results demonstrated that the DIPPAAAs were stable in the mobile phase (5 mmol/L NH4Ac-MeCN (80:20,v/v, pH7.5) within 48 h.

  4. Transcriptome sequencing revealed the transcriptional organization at ribosome-mediated attenuation sites in Corynebacterium glutamicum and identified a novel attenuator involved in aromatic amino acid biosynthesis.

    Science.gov (United States)

    Neshat, Armin; Mentz, Almut; Rückert, Christian; Kalinowski, Jörn

    2014-11-20

    The Gram-positive bacterium Corynebacterium glutamicum belongs to the order Corynebacteriales and is used as a producer of amino acids at industrial scales. Due to its economic importance, gene expression and particularly the regulation of amino acid biosynthesis has been investigated extensively. Applying the high-resolution technique of transcriptome sequencing (RNA-seq), recently a vast amount of data has been generated that was used to comprehensively analyze the C. glutamicum transcriptome. By analyzing RNA-seq data from a small RNA cDNA library of C. glutamicum, short transcripts in the known transcriptional attenuators sites of the trp operon, the ilvBNC operon and the leuA gene were verified. Furthermore, whole transcriptome RNA-seq data were used to elucidate the transcriptional organization of these three amino acid biosynthesis operons. In addition, we discovered and analyzed the novel attenuator aroR, located upstream of the aroF gene (cg1129). The DAHP synthase encoded by aroF catalyzes the first step in aromatic amino acid synthesis. The AroR leader peptide contains the amino acid sequence motif F-Y-F, indicating a regulatory effect by phenylalanine and tyrosine. Analysis by real-time RT-PCR suggests that the attenuator regulates the transcription of aroF in dependence of the cellular amount of tRNA loaded with phenylalanine when comparing a phenylalanine-auxotrophic C. glutamicum mutant fed with limiting and excess amounts of a phenylalanine-containing dipeptide. Additionally, the very interesting finding was made that all analyzed attenuators are leaderless transcripts.

  5. Dissociations of copper(II)-containing complexes of aromatic amino acids: radical cations of tryptophan, tyrosine, and phenylalanine.

    Science.gov (United States)

    Siu, Chi-Kit; Ke, Yuyong; Guo, Yuzhu; Hopkinson, Alan C; Siu, K W Michael

    2008-10-14

    The dissociations of two types of copper(II)-containing complexes of tryptophan (Trp), tyrosine (Tyr), or phenylalanine (Phe) are described. The first type is the bis-amino acid complex, [Cu(II)(M)(2)].(2+), where M = Trp, Tyr, or Phe; the second [Cu(II)(4Cl-tpy)(M)].(2+), where 4Cl-tpy is the tridendate ligand 4'-chloro-2,2':6',2''-terpyridine. Dissociations of the Cu(ii) bis-amino acid complexes produce abundant radical cation of the amino acid, M.(+), and/or its secondary products. By contrast, dissociations of the 4Cl-tpy-bearing ternary complexes give abundant M.(+) only for Trp. Density functional theory (DFT) calculations show that for Tyr and Phe, amino-acid displacement reactions by H(2)O and CH(3)OH (giving [Cu(II)(4Cl-tpy)(H(2)O)].(2+) and [Cu(II)(4Cl-tpy)(CH(3)OH)].(2+)) are energetically more favorable than dissociative electron transfer (giving M.(+) and [Cu(I)(4Cl-tpy)](+)). The fragmentation pathway common to all these [Cu(II)(4Cl-tpy)(M)].(2+) ions is the loss of NH(3). DFT calculations show that the loss of NH(3) proceeds via a "phenonium-type" intermediate. Dissociative electron transfer in [Cu(II)(4Cl-tpy)(M-NH(3))].(2+) results in [M-NH(3)].(+). The [Phe-NH(3)] (+) ion dissociates facilely by eliminating CO(2) and giving a metastable phenonium-type ion that rearranges readily into the styrene radical cation.

  6. Amino Acid Metabolism Disorders

    Science.gov (United States)

    ... this process. One group of these disorders is amino acid metabolism disorders. They include phenylketonuria (PKU) and maple syrup urine disease. Amino acids are "building blocks" that join together to form ...

  7. Induction of aromatic amino acids and phenylpropanoid compounds in Scrophularia striata Boiss. cell culture in response to chitosan-induced oxidative stress.

    Science.gov (United States)

    Kamalipourazad, Maryam; Sharifi, Mohsen; Maivan, Hassan Zare; Behmanesh, Mehrdad; Chashmi, Najmeh Ahmadian

    2016-10-01

    Manipulation of cell culture media by elicitors is one of most important strategies to inducing secondary metabolism for the production of valuable metabolites. In this investigation, inducing effect of chitosan on physiological, biochemical, and molecular parameters were investigated in cell suspension cultures of Scrophularia striata Boiss. The results showed that chitosan concentration and time of elicitation are determinants of the effectiveness of the elicitor. Accumulation of aromatic amino acids (phenylalanine [Phe] and tyrosine [Tyr]), phenylpropanoid compounds (phenolic acids [PAs] and echinacoside [ECH]), hydrogen peroxide (H2O2) production, phenylalanine ammonia-lyase (PAL) activity and gene expression, and antioxidant enzymes (superoxide dismutase [SOD], peroxidase [POX], catalase [CAT]) activities were altered by changing the exposure time of elicitation. Results showed that, upon elicitation with chitosan, oxidative events were induced, antioxidant responses of S. striata cells were boosted through enhanced activity of an effective series of scavenging enzymes (SOD, CAT, and POX), and biosynthesis of non-enzymatic antioxidants (ECH and PAs [cinnamic, p-coumaric and, caffeic acids]). The increase in amino acid content and PAL activity at early days of exposure to chitosan was related with rises in phenolic compounds. These results provide evidence that chitosan by up-regulation of PAL gene differentially improves the production of phenylpropanoid compounds, which are of medical commercial value with good biotechnological prospects.

  8. Spinal cord hemisection facilitates aromatic L-amino acid decarboxylase cells to produce serotonin in the subchronic but not the chronic phase

    DEFF Research Database (Denmark)

    Azam, Bushra; Wienecke, Jacob; Jensen, Dennis Bo;

    2015-01-01

    12) were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were......Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT) and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC) cells to produce...... 5-HT from its precursor (5-hydroxytryptophan, 5-HTP) is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T...

  9. Parenteral Nutrition: Amino Acids

    Science.gov (United States)

    Hoffer, Leonard John

    2017-01-01

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness. PMID:28287411

  10. Parenteral Nutrition: Amino Acids.

    Science.gov (United States)

    Hoffer, Leonard John

    2017-03-10

    There is growing interest in nutrition therapies that deliver a generous amount of protein, but not a toxic amount of energy, to protein-catabolic critically ill patients. Parenteral amino acids can achieve this goal. This article summarizes the biochemical and nutritional principles that guide parenteral amino acid therapy, explains how parenteral amino acid solutions are formulated, and compares the advantages and disadvantages of different parenteral amino acid products with enterally-delivered whole protein products in the context of protein-catabolic critical illness.

  11. Eucalyptus ESTs associated with resistance to herbicide inhibitors of aromatic and branched-chain amino acid synthesis

    Directory of Open Access Journals (Sweden)

    Edivaldo Domingues Velini

    2005-01-01

    Full Text Available Herbicides inhibit enzymatic systems of plants. Acetolactate synthase (ALS, EC = 4.1.3.18 and 5-enolpyruvylshikimate-3-phosphate synthase (EPSPS, EC 2.5.1.19 are key enzymes for herbicide action. Hundreds of compounds inhibit ALS. This enzyme is highly variable, enabling the selective control of weeds in a number of crops. Glyphosate, the only commercial herbicide inhibiting EPSPS is widely used for non-selective control of weeds in many crops. Recently, transgenic crops resistant to glyphosate were developed and have been used by farmers. The aim of this study was the data mining of eucalypt expressed sequence tags (ESTs in the FORESTs Genome Project database (https://forests.esalq.usp.br related to these enzymes. Representative amino acid sequences from the NCBI database associated with ALS and EPSPS were blasted with ESTs from the FORESTs database using the tBLASTx option of the blast tool. The best blasting reads and clusters from FORESTs, represented as nucleotide sequences, were blasted back with the NCBI database to evaluate the level of similarity with available sequences from different species. One and seven clusters were identified as showing high similarity with EPSPS and ALS sequences from the literature, respectively. The alignment of EPSPS sequences allowed the identification of conserved regions that can be used to design specific primers for additional sequencings.

  12. 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;…

  13. Noncovalent chirality sensing ensembles for the detection and reaction monitoring of amino acids, peptides, proteins, and aromatic drugs.

    Science.gov (United States)

    Biedermann, Frank; Nau, Werner M

    2014-05-26

    Ternary complexes between the macrocyclic host cucurbit[8]uril, dicationic dyes, and chiral aromatic analytes afford strong induced circular dichroism (ICD) signals in the near-UV and visible regions. This allows for chirality sensing and peptide-sequence recognition in water at low micromolar analyte concentrations. The reversible and noncovalent mode of binding ensures an immediate response to concentration changes, which allows the real-time monitoring of chemical reactions. The introduced supramolecular method is likely to find applications in bioanalytical chemistry, especially enzyme assays, for drug-related analytical applications, and for continuous monitoring of enantioselective reactions, particularly asymmetric catalysis.

  14. Catalysis by amino acid-derived tetracoordinate complexes: enantioselective addition of dialkylzincs to aliphatic and aromatic aldehydes.

    Science.gov (United States)

    Dangel, B D; Polt, R

    2000-09-21

    Me(2)Zn and Et(2)Zn added to aromatic and aliphatic aldehydes in the presence of 3 mol % of 2. (S)-1-Phenylethanol (91% ee) and (S)-1-phenylpropanol (86% ee) were synthesized from benzaldehyde and (S)-1-furan-2-yl-1-propanol (86% ee) from 2-furaldehyde. Nonanal and 3-phenylpropanal provided (S)-3-undecanol (96% ee) and (S)-1-phenyl-3-pentanol (94% ee). A solid-phase variant was effective with reduced ee's (e.g., 86% ee --> 79% ee) for (S)-1-phenylpropanol.

  15. 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.

  16. Amino Acids and Chirality

    Science.gov (United States)

    Cook, Jamie E.

    2012-01-01

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

  17. 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.

  18. First hyperpolarizability of the natural aromatic amino acids tryptophan, tyrosine, and phenylalanine and the tripeptide lysine-tryptophan-lysine determined by hyper-Rayleigh scattering.

    Science.gov (United States)

    Duboisset, J; Matar, G; Russier-Antoine, I; Benichou, E; Bachelier, G; Jonin, Ch; Ficheux, D; Besson, F; Brevet, P F

    2010-11-01

    We report the first hyperpolarizability of tryptophan (Trp) and tyrosine (Tyr) and an upper limit for that of phenylalanine (Phe), three natural aromatic amino acids. The measurements were performed with hyper-Rayleigh scattering in an aqueous Tris buffer solution at a pH of 8.5 and 150 mM salt concentration with a fundamental wavelength of 780 nm. A value of (4.7 ± 0.7) × 10(-30) esu is found for Trp and (4.1 ± 0.7) × 10(-30) esu for Tyr whereas the upper limit of 1.4 × 10(-30) esu is found for that of Phe due to its limited solubility. The influence of the presence of lysine (Lys) in close vicinity of Trp is investigated with a measurement of the first hyperpolarizabilty of Trp in an excess of Lys and compared to the first hyperpolarizability obtained for the tripeptide Lys-Trp-Lys. The clear decrease of the values measured in these two cases indicates that the first hyperpolarizabilty of Trp is very sensitive to its local environment.

  19. Spinal Cord Hemisection Facilitates Aromatic L-Amino Acid Decarboxylase Cells to Produce Serotonin in the Subchronic but Not the Chronic Phase

    Directory of Open Access Journals (Sweden)

    Bushra Azam

    2015-01-01

    Full Text Available Neuromodulators, such as serotonin (5-hydroxytryptamine, 5-HT and noradrenalin, play an essential role in regulating the motor and sensory functions in the spinal cord. We have previously shown that in the rat spinal cord the activity of aromatic L-amino acid decarboxylase (AADC cells to produce 5-HT from its precursor (5-hydroxytryptophan, 5-HTP is dramatically increased following complete spinal cord transection. In this study, we investigated whether a partial loss of 5-HT innervation could similarly increase AADC activity. Adult rats with spinal cord hemisected at thoracic level (T11/T12 were used with a postoperation interval at 5 days or 60 days. Using immunohistochemistry, first, we observed a significant reduction in the density of 5-HT-immunoreactive fibers in the spinal cord below the lesion on the injured side for both groups. Second, we found that the AADC cells were similarly expressed on both injured and uninjured sides in both groups. Third, increased production of 5-HT in AADC cells following 5-HTP was seen in 5-day but not in 60-day postinjury group. These results suggest that plastic changes of the 5-HT system might happen primarily in the subchronic phase and for longer period its function could be compensated by plastic changes of other intrinsic and/or supraspinal modulation systems.

  20. Induction of aromatic L-amino acid decarboxylase mRNA by interleukin-1 beta and prostaglandin E2 in PC12 cells.

    Science.gov (United States)

    Li, X M; Juorio, A V; Boulton, A A

    1994-05-01

    Aromatic 1-amino acid decarboxylase (AADC) is involved in the synthesis of the putative neurotransmitters dopamine (DA), norepinephrine (NA) and 5-hydroxytryptamine (5-HT). We report here that the gene expression of AADC can be regulated by interleukin (IL) 1-beta and prostaglandin (PG) E2 in PC12 cells. The cells were treated with different doses of IL 1-beta and PGE2 for 3 days. Slot blot hybridization was performed to detect AADC mRNA and Western immunoblot to detect AADC protein. The cDNA probe for rat AADC was generated by the PCR method. IL 1-beta and PGE2 produced a dose- and time-dependent up-regulation in AADC mRNA levels (up to 200% of the control values) which was followed by a stable increase in AADC protein. The data further support the suggestion that AADC is a regulated enzyme and that the regulation occurs at the level of gene expression. Because IL-1 is synthesized, and acts locally, within the brain to influence neuronal and glial functions, it has been proposed to be a mediator with both beneficial and detrimental responses to inflammation and injury. The regulation of AADC by IL-1 may indicate a possible involvement for AADC in neuronal injury and recovery. Since IL-1 promotes PGE2 formation, its effects may be occurring by increasing level of PGE2.

  1. Synthesis, characterization and biological evaluation of bile acid-aromatic/heteroaromatic amides linked via amino acids as anti-cancer agents.

    Science.gov (United States)

    Agarwal, Devesh S; Anantaraju, Hasitha Shilpa; Sriram, Dharmarajan; Yogeeswari, Perumal; Nanjegowda, Shankara H; Mallu, P; Sakhuja, Rajeev

    2016-03-01

    A series of bile acid (Cholic acid and Deoxycholic acid) aryl/heteroaryl amides linked via α-amino acid were synthesized and tested against 3 human cancer cell-lines (HT29, MDAMB231, U87MG) and 1 human normal cell line (HEK293T). Some of the conjugates showed promising results to be new anticancer agents with good in vitro results. More specifically, Cholic acid derivatives 6a (1.35 μM), 6c (1.41 μM) and 6m (4.52 μM) possessing phenyl, benzothiazole and 4-methylphenyl groups showed fairly good activity against the breast cancer cell line with respect to Cisplatin (7.21 μM) and comparable with respect to Doxorubicin (1 μM), while 6e (2.49μM), 6i (2.46 μM) and 6m (1.62 μM) showed better activity against glioblastoma cancer cell line with respect to both Cisplatin (2.60 μM) and Doxorubicin (3.78 μM) drugs used as standards. Greater than 65% of the compounds were found to be safer on human normal cell line.

  2. The novel R347g pathogenic mutation of aromatic amino acid decarboxylase provides additional molecular insights into enzyme catalysis and deficiency.

    Science.gov (United States)

    Montioli, Riccardo; Paiardini, Alessandro; Kurian, Manju A; Dindo, Mirco; Rossignoli, Giada; Heales, Simon J R; Pope, Simon; Voltattorni, Carla Borri; Bertoldi, Mariarita

    2016-06-01

    We report here a clinical case of a patient with a novel mutation (Arg347→Gly) in the gene encoding aromatic amino acid decarboxylase (AADC) that is associated with AADC deficiency. The variant R347G in the purified recombinant form exhibits, similarly to the pathogenic mutation R347Q previously studied, a 475-fold drop of kcat compared to the wild-type enzyme. In attempting to unravel the reason(s) for this catalytic defect, we have carried out bioinformatics analyses of the crystal structure of AADC-carbidopa complex with the modelled catalytic loop (residues 328-339). Arg347 appears to interact with Phe103, as well as with both Leu333 and Asp345. We have then prepared and characterized the artificial F103L, R347K and D345A mutants. F103L, D345A and R347K exhibit about 13-, 97-, and 345-fold kcat decrease compared to the wild-type AADC, respectively. However, unlike F103L, the R347G, R347K and R347Q mutants as well as the D345A variant appear to be more defective in catalysis than in protein folding. Moreover, the latter mutants, unlike the wild-type protein and the F103L variant, share a peculiar binding mode of dopa methyl ester consisting of formation of a quinonoid intermediate. This finding strongly suggests that their catalytic defects are mainly due to a misplacement of the substrate at the active site. Taken together, our results highlight the importance of the Arg347-Leu333-Asp345 hydrogen-bonds network in the catalysis of AADC and reveal the molecular basis for the pathogenicity of the variants R347. Following the above results, a therapeutic treatment for patients bearing the mutation R347G is proposed.

  3. Azetidinic amino acids

    DEFF Research Database (Denmark)

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

    2005-01-01

    of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...

  4. Amino Acid Catabolism in Plants.

    Science.gov (United States)

    Hildebrandt, Tatjana M; Nunes Nesi, Adriano; Araújo, Wagner L; Braun, Hans-Peter

    2015-11-02

    Amino acids have various prominent functions in plants. Besides their usage during protein biosynthesis, they also represent building blocks for several other biosynthesis pathways and play pivotal roles during signaling processes as well as in plant stress response. In general, pool sizes of the 20 amino acids differ strongly and change dynamically depending on the developmental and physiological state of the plant cell. Besides amino acid biosynthesis, which has already been investigated in great detail, the catabolism of amino acids is of central importance for adjusting their pool sizes but so far has drawn much less attention. The degradation of amino acids can also contribute substantially to the energy state of plant cells under certain physiological conditions, e.g. carbon starvation. In this review, we discuss the biological role of amino acid catabolism and summarize current knowledge on amino acid degradation pathways and their regulation in the context of plant cell physiology.

  5. 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....

  6. 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.

  7. Protein and amino acid nutrition

    Science.gov (United States)

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

  8. Racemization of Meteoritic Amino Acids

    Science.gov (United States)

    Cohen, Barbara A.; Chyba, Christopher F.

    2000-05-01

    Meteorites may have contributed amino acids to the prebiotic Earth, affecting the global ratio of right-handed to left-handed (D/L) molecules. We calculate D/L ratios for seven biological, α-hydrogen, protein amino acids over a variety of plausible parent body thermal histories, based on meteorite evidence and asteroid modeling. We show that amino acids in meteorites do not necessarily undergo complete racemization by the time they are recovered on Earth. If the mechanism of amino acid formation imposes some enantiomeric preference on the amino acids, a chiral signature can be retained through the entire history of the meteorite. Original enantiomeric excesses in meteorites such as Murchison, which have undergone apparently short and cool alteration scenarios, should have persisted to the present time. Of the seven amino acids for which relevant data are available, we expect glutamic acid, isoleucine, and valine, respectively, to be the most likely to retain an initial enantiomeric excess, and phenylalanine, aspartic acid, and alanine the least. Were the D/L ratio initially identical in each amino acid, final D/L ratios could be used to constrain the initial ratio and the thermal history experienced by the whole suite.

  9. Introduction of Deuterated Aromatic Amino Acids  [2,3,4,5,6-2H5]phenylalanine, [3,5-2H2]tyrosine and [2,4,5,6,7-2H5]tryptophan into a Molecule of Photochrome Trans-membrane Protein Bacteriorhodopsin

    Directory of Open Access Journals (Sweden)

    Oleg Mosin

    2015-09-01

    Full Text Available It was carried out the introduction of functionally important deuterated aromatic amino acids  [2,3,4,5,6-2H5]phenylalanine, [3,5-2H2]tyrosine and [2,4,5,6,7-2H5]tryptophan into a molecule of photochrome trans-membrane protein bacteriorhodopsin, synthesized by a photo-organotrophic halobacterium Halobacterium halobium ET 1001. The deuterated protein (output 810 mg was isolated from purple membranes by cellular autolysis by distilled water, processing of bacterial biomass by ultrasound at 22 KHz, alcohol extraction of low and high-weight molecular impurities, cellular RNA, carotenoids and lipids, with the subsequent solubilization of final product with 0,5 % (w/v SDS-Na and fractionation by methanol, gel filtration chromatography on Sephadex G-200, reverse-phase HPLC and EI impact mass-spectrometry of methyl esters of N-Dns-[2H]derivatives of amino acids. Deuterium was detected in all residues of aromatic amino acids. However, the presence in the EI mass spectrum of the BR hydrolysate the peaks [M]+ of semi-deuterated analogues of aromatic amino acids  phenylalanine with [M]+ at m/z = 413418, tyrosine  with [M]+ at m/z = 428430 and tryptophan  with [M]+ at m/z = 453457 with different levels of contributions to the deuterium enrichment of molecules testifies about the conservation of the minor pathways of biosynthesis of aromatic amino acids de novo.

  10. 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.

  11. Effect of water coordination on competition between π and non-π cation binding sites in aromatic amino acids: L-phenylalanine, L-tyrosine, and L-tryptophan Li+, Na +, and K+ complexes.

    Science.gov (United States)

    Remko, Milan; Šoralová, Stanislava

    2012-04-01

    Quantum chemistry methods have been applied to charged complexes of the alkali metals Li(+), Na(+), and K(+) with the aromatic amino acids (AAAs) phenylalanine (Phe), tyrosine (Tyr), and tryptophan (Trp). The geometries of 72 different complexes (Phe·M, Tyr·M, Trp·M, M is Li(+), Na(+), or K(+)) were completely optimized at the B3LYP/6-311+G(d,p) level of density functional theory. The solvent effect on the geometry and stability of individual complexes was studied by making use of a microsolvation model. The interaction enthalpies, entropies, and Gibbs energies of nine different complexes of the systems Phe·M, Tyr·M, and Trp·M (M is Li(+), Na(+), or K(+)) were also determined at the B3LYP density functional level of theory. The calculated Gibbs binding energies of the M(+)-AAA complexes follow the order Phe < Tyr < Trp for all three metal cations studied. Among the three AAAs studied, the indole ring of Trp is the best π donor for alkali metal cations. Our calculations demonstrated the existence of strong cation-π interactions between the alkali metals and the aromatic side chains of the three AAAs. These AAAs comprise about 8% of all known protein sequences. Thus, besides the potential for hydrogen-bond interaction, aromatic residues of Phe, Tyr, and Trp show great potential for π-donor interactions. The existence of cation-π interaction in proteins has also been demonstrated experimentally. However, more complex experimental studies of metal cation-π interaction in diverse biological systems will no doubt lead to more exact validation of these investigations.

  12. (-)-Hydroxycitric Acid Nourishes Protein Synthesis via Altering Metabolic Directions of Amino Acids in Male Rats.

    Science.gov (United States)

    Han, Ningning; Li, Longlong; Peng, Mengling; Ma, Haitian

    2016-08-01

    (-)-Hydroxycitric acid (HCA), a major active ingredient of Garcinia Cambogia extracts, had shown to suppress body weight gain and fat accumulation in animals and humans. While, the underlying mechanism of (-)-HCA has not fully understood. Thus, this study was aimed to investigate the effects of long-term supplement with (-)-HCA on body weight gain and variances of amino acid content in rats. Results showed that (-)-HCA treatment reduced body weight gain and increased feed conversion ratio in rats. The content of hepatic glycogen, muscle glycogen, and serum T4 , T3 , insulin, and Leptin were increased in (-)-HCA treatment groups. Protein content in liver and muscle were significantly increased in (-)-HCA treatment groups. Amino acid profile analysis indicated that most of amino acid contents in serum and liver, especially aromatic amino acid and branched amino acid, were higher in (-)-HCA treatment groups. However, most of the amino acid contents in muscle, especially aromatic amino acid and branched amino acid, were reduced in (-)-HCA treatment groups. These results indicated that (-)-HCA treatment could reduce body weight gain through promoting energy expenditure via regulation of thyroid hormone levels. In addition, (-)-HCA treatment could promote protein synthesis by altering the metabolic directions of amino acids. Copyright © 2016 John Wiley & Sons, Ltd.

  13. 芳香族氨基酸对沼泽红假单胞菌合成CoQ10的影响%Effects of aromatic amino acids on the biosynthesis of CoQ10 in Rhodopseudomonas palustris

    Institute of Scientific and Technical Information of China (English)

    蒋世云; 余龙江; 申晓林; 熊欣; 简艳

    2008-01-01

    CoQ10 has been used not only as a drug but also as a food supplement because of its various Dhysi ological and biochemical activities.Microbial fermentation is a main way for the commercial production of CoQ10.The quinoid nucleus of CoQ10 and aromatic amino acids are synthesized from the shikimate pathway in bacteria and there are some effects of them on another biosynthesis.The impacts of aromatic amino acids on the biosynthesis of CoQ10 in Rhodopseudomnas palustris J001 were investigated with feeding aromatic amino acids at the end of the logarithmic phase during incubation.The results showed that the feeding of tryptophan(above 15 mg/L) strongly repressed the biosynthesis of CoQ10.There were also some slightly unfavorable effects of feeding of phenylalanine(50 mg/L)and tyrosine(above 200 rag/L)on the biosynthesis of CoQl0.However,the biosynthe sis of CoQ10 could be enhanced by feeding phenylalanine(above 75 mg/L)Or tyrosine(from 75 to 1 75 mg/L).The content of CoQ10 in the strain was found to be the highest up tO(25.6±1.3)mg CoQ10/g dried biomass when feeding phenylalanine(1 00 mg/L)+tyrosine(1 50 mg/L),which was 52.2% higher than that in the control with no additional amino acids in the medium.The results indicated that the biosynthesis of CoqIo was affected by the three aromatic amino acids.It can be concluded that the biosynthesis of CoQ10 in strain is favorable by feeding appropriate amount of phenylalanien and tyrosine without tryptophan.%CoQ10具有呼吸链电子传递者、抗氧化性、调控基因表达等多种生理生化功能.目前不仅用作药物也用作食品添加剂.微生物发酵法是当前生产CoQ10的主要方法.在细菌中,芳香族氨基酸和CoQ10的苯核环都是通过莽草酸途径合成;它们在生物体中各自的合成存在着相互调控作用.本试验通过在培养过程中添加芳香族氨基酸来考察了其对沼泽红假单胞菌J001合成CoQ10的影响.结果表明:当色氨酸添加量≥15 mg/L时对CoQ10

  14. 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.

  15. 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...

  16. Unnatural reactive amino acid genetic code additions

    Science.gov (United States)

    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.

  17. 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.

  18. 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...

  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. Bacterial conversion of phenylalanine and aromatic carboxylic acids into dihydrodiols.

    Science.gov (United States)

    Wegst, W; Tittmann, U; Eberspächer, J; Lingens, F

    1981-03-15

    Strain E of chloridazon-degrading bacteria, when grown on L-phenylalanine accumulates cis-2,3-dihydro-2,3-dihydroxyphenylalanine. In experiments with resting cells and during growth the bacterium converts the aromatic carboxylic acids phenylacetate, phenylpropionate, phenylbutyrate and phenyl-lactate into the corresponding cis-2,3-dihydrodiol compounds. The amino acids L-phenylalanine, N-acetyl-L-phenylalanine and t-butyloxycarbonyl-L-phenylalanine were also transformed into dihydrodiols. All seven dihydrodiols, thus obtained, were characterized both by conventional analytical techniques and by the ability to serve as substrates for a cis-dihydrodiol dehydrogenase.

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

    Science.gov (United States)

    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. Concentrations of plasma isoleucine, valine and phenylalanine subsequently decreased after ingestion, and those of methionine and tyrosine tended to decrease. The effects of ingested leucine on other plasma amino acids were biphasic, being higher at lower doses (10-20 mg/kg body weight). Isoleucine or valine intake also caused corresponding plasma amino acid concentrations to rapidly elevate, and peaks at 30-40 min after ingestion were much higher than that of plasma leucine after leucine ingestion. However, the increase in plasma isoleucine and valine concentrations essentially did not affect those of other plasma amino acids. The rate of decline among peak plasma BCAA concentrations was the highest for leucine, followed by isoleucine and valine. Oral mixed BCAAs promoted the decline in plasma isoleucine and valine concentrations. These results suggest that plasma leucine is a regulator of the plasma concentrations of BCAAs, methionine and aromatic amino acids.

  2. 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).

  3. 芳香族氨基酸添加提高井冈霉素产量的研究%Enhanced validamycin production by addition of aromatic amino acid

    Institute of Scientific and Technical Information of China (English)

    魏振华; 钟建江

    2013-01-01

    目的 通过添加芳香族氨基酸促进井冈霉素生物合成起始单位的供应,提高其发酵产量.方法 优化苯丙氨酸添加时间和浓度确定最优添加条件,分析前体代谢相关的酶活考察其影响机制.结果 确定苯丙氨酸最佳添加条件为在发酵第24h添加0.1g/L.发现37℃时苯丙氨酸的添加提高了井冈霉素A产量,但在42℃条件下提高幅度大大降低.通过分析6-磷酸葡萄糖脱氢酶酶活,发现芳香族氨基酸添加并未影响其酶活.结论 苯丙氨酸的添加能有效提高井冈霉素发酵产量近60%.苯丙氨酸的添加可能通过反馈抑制降低了戊糖磷酸途径中中间体的消耗,从而为井冈霉素合成提供了更加充足的7-磷酸景天庚酮糖.%Objective To enhance validamycin production, aromatic amino acid was added to the medium to increase the supply of precursor for validamycin. Methods Phenylalanine, tryptophan and tyrosine were added to the medium to study the effect of aromatic amino acids on validamycin production. Addition time and concentration of phenylalanine were optimized to find out the optimal condition. The glucose-6-phosphate dehydrogenase (G6PDH) activity which related to validanycin precursor metabolism was analyzed to study its mechanism. Results The results showed that phenylalanine had the best effect on validamycin production. The optimal condition was 0.1 g/L phenylalanine added at 24h, which enhanced validamycin production by 60%. The addition of phenylalanine enhanced validamycin production greatly at 37℃, but not so much at 42 ℃. G6PDH activity was higher at 42 ℃ than 37℃, and it was found that the addition of phenylalanine had no significant effect on glucose-6-phosphate dehydrogenase activity. Conclusion Validamycin production was enhanced 60% by addition of phenylalanine. The addition of phenylalanine might inhibited the consumption of intermediates in pentose phosphate pathway, which resaved precursor for validamycin

  4. 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.

  5. Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans

    DEFF Research Database (Denmark)

    Berg, Ronan Mg; Taudorf, Sarah; Bailey, Damian M;

    2010-01-01

    Alterations in circulating large neutral amino acids (LNAAs), leading to a decrease in the plasma ratio between branched-chain and aromatic amino acids (BCAA/AAA ratio), may be involved in sepsis-associated encephalopathy. We hypothesised that a decrease in the BCAA/AAA ratio occurs along with a ...

  6. Cerebral net exchange of large neutral amino acids after lipopolysaccharide infusion in healthy humans

    DEFF Research Database (Denmark)

    2010-01-01

    Alterations in circulating large neutral amino acids (LNAAs), leading to a decrease in the plasma ratio between branched-chain and aromatic amino acids (BCAA/AAA ratio), may be involved in sepsis-associated encephalopathy. We hypothesised that a decrease in the BCAA/AAA ratio occurs along...

  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. Microbial production of amino acids in Japan.

    Science.gov (United States)

    Kumagai, H

    2000-01-01

    The microbial biotechnology of amino acids production which was developed and industrialized in Japan have been summarized. The amino acids include L-glutamic acid, L-lysine, L-threonine, L-aspartic acid, L-alanine, L-cysteine, L-dihydroxyphenylalanine, D-p-hydroxyphenyl-glycine, and hydroxy-L-proline.

  9. 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...

  10. 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.

  11. 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.

  12. Effect of domoic acid on brain amino acid levels.

    Science.gov (United States)

    Durán, R; Arufe, M C; Arias, B; Alfonso, M

    1995-03-01

    The administration of Domoic Acid (Dom) in a 0.2 mg/kg i.p. dose induces changes in the levels of amino acids of neurochemical interest (Asp, Glu, Gly, Tau, Ala, GABA) in different rat brain regions (hypothalamus, hippocampus, amygdala, striatum, cortex and midbrain). The most affected amino acid is the GABA, the main inhibitory amino acid neurotransmitter, whereas glutamate, the main excitatory amino acid, is not affected. The rat brain regions that seem to be the main target of the Dom action belong to the limbic system (hippocampus, amygdala). The possible implication of the amino acids in the actions of Dom is also discussed.

  13. Study on Reduction of β-Aromatic Amino Substituted Triazolyl Ketene Compounds

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A series of β-aromatic amino substituted triazolyl ketenes were reduced at different conditions to enols and saturated alcohols, respectively.The preliminary biological tests showed that some of them exhibit good fungicidal activities.

  14. 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.

  15. 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.

  16. Nutritional value of D-amino acids, D-peptides, and amino acid derivatives in mice.

    Science.gov (United States)

    Friedman, Mendel; Levin, Carol E

    2012-01-01

    This paper describes 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 for such determinations may be preferable to protein-based diets.

  17. Enantioselective binding of amino acids and amino alcohols by self-assembled chiral basket-shaped receptors

    NARCIS (Netherlands)

    Escuder, B.; Rowan, A.E.; Feiters, M.C.; Nolte, R.J.M.

    2004-01-01

    Amino acid appended diphenylglycoluril-based chiral molecular receptors 2 and 3 have been prepared and their aggregation has been studied in water at various pH's and in chloroform. The binding of several biologically relevant guests with aromatic moieties to these aggregates has been studied with U

  18. 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.

  19. 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.

  20. 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)

  1. 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

  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. Differential distribution of amino acids in plants.

    Science.gov (United States)

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

    2017-03-15

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

  4. 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...

  5. Highly Energetic, Low Sensitivity Aromatic Peroxy Acids.

    Science.gov (United States)

    Gamage, Nipuni-Dhanesha H; Stiasny, Benedikt; Stierstorfer, Jörg; Martin, Philip D; Klapötke, Thomas M; Winter, Charles H

    2016-02-18

    The synthesis, structure, and energetic materials properties of a series of aromatic peroxy acid compounds are described. Benzene-1,3,5-tris(carboperoxoic) acid is a highly sensitive primary energetic material, with impact and friction sensitivities similar to those of triacetone triperoxide. By contrast, benzene-1,4-bis(carboperoxoic) acid, 4-nitrobenzoperoxoic acid, and 3,5-dinitrobenzoperoxoic acid are much less sensitive, with impact and friction sensitivities close to those of the secondary energetic material 2,4,6-trinitrotoluene. Additionally, the calculated detonation velocities of 3,5-dinitrobenzoperoxoic acid and 2,4,6-trinitrobenzoperoxoic acid exceed that of 2,4,6-trinitrotoluene. The solid-state structure of 3,5-dinitrobenzoperoxoic acid contains intermolecular O-H⋅⋅⋅O hydrogen bonds and numerous N⋅⋅⋅O, C⋅⋅⋅O, and O⋅⋅⋅O close contacts. These attractive lattice interactions may account for the less sensitive nature of 3,5-dinitrobenzoperoxoic acid.

  6. Gemini surfactants from natural amino acids.

    Science.gov (United States)

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

    2014-03-01

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

  7. 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.

  8. 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.

  9. 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.

  10. 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.

  11. Amino Acids in the Martian Meteorite Nakhla

    Science.gov (United States)

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

    1999-08-01

    A suite of protein and nonprotein amino acids were detected with high-performance liquid chromatography in the water- and acid-soluble components of an interior fragment of the Martian meteorite Nakhla, which fell in Egypt in 1911. Aspartic and glutamic acids, glycine, alanine, β -alanine, and γ -amino-n-butyric acid (γ -ABA) were the most abundant amino acids detected and were found primarily in the 6 M HCl-hydrolyzed, hot water extract. The concentrations ranged from 20 to 330 parts per billion of bulk meteorite. The amino acid distribution in Nakhla, including the D/L ratios (values range from contamination of Martian meteorites after direct exposure to the terrestrial environment has important implications for Mars sample-return missions and the curation of the samples from the time of their delivery to Earth.

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

    Science.gov (United States)

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

    1973-01-01

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

  13. Metabolic Effects of Dietary Proteins, Amino Acids and The Other Amine Consisting Compounds on Cardiovascular System.

    Directory of Open Access Journals (Sweden)

    Elif Uğur

    2017-02-01

    Full Text Available During the prevention and treatment of cardiovascular diseases, first cause of deaths in the world, diet has a vital role. While nutrition programs for the cardiovascular health generally focus on lipids and carbohydrates, effects of proteins are not well concerned. Thus this review is written in order to examine effect of proteins, amino acids, and the other amine consisting compounds on cardiovascular system. Because of that animal or plant derived proteins have different protein composition in different foods such as dairy products, egg, meat, chicken, fish, pulse and grains, their effects on blood pressure and regulation of lipid profile are unlike. In parallel amino acids made up proteins have different effect on cardiovascular system. From this point, sulfur containing amino acids, branched chain amino acids, aromatic amino acids, arginine, ornithine, citrulline, glycine, and glutamine may affect cardiovascular system in different metabolic pathways. In this context, one carbon metabolism, synthesis of hormone, stimulation of signaling pathways and effects of intermediate and final products that formed as a result of amino acids metabolism is determined. Despite the protein and amino acids, some other amine consisting compounds in diet include trimethylamine N-oxide, heterocyclic aromatic amines, polycyclic aromatic hydrocarbons and products of Maillard reaction. These amine consisting compounds generally increase the risk for cardiovascular diseases by stimulating oxidative stress, inflammation, and formation of atherosclerotic plaque.

  14. 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.

  15. 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.

  16. 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.

  17. 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.

  18. Amino acids in the Martian meteorite Nakhla.

    Science.gov (United States)

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

    1999-08-03

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

  19. 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}.

  20. 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.

  1. An astrophysically-relevant mechanism for amino acid enantiomer enrichment

    NARCIS (Netherlands)

    P. Fletcher, S.; B. C. Jagt, R.; Feringa, B.L.

    2007-01-01

    The sublimation of low ee amino acids was examined while exploring simple mechanisms by which high ee amino acids can be generated under conditions that exist in space; significant enantioenrichment of a variety of amino acids by sublimation was achieved.

  2. 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.

  3. Chlorine dioxide reaction with selected amino acids in water

    Energy Technology Data Exchange (ETDEWEB)

    Navalon, Sergio; Alvaro, Mercedes [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain); Garcia, Hermenegildo, E-mail: hgarcia@qim.upv.es [Department of Chemistry, Universidad Politecnica de Valencia, Camino de Vera S/N, 46022 Valencia (Spain)

    2009-05-30

    Chlorine dioxide is a hypochlorite alternative disinfectant agent. In this context, we have determined the products formed in the reaction of ClO{sub 2} 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 ClO{sub 2} 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 ClO{sub 2} 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 ClO{sub 2} with ubiquitous amino acids present in natural waters.

  4. Chemical modification of amino acids by atmospheric-pressure cold plasma in aqueous solution

    Science.gov (United States)

    Takai, Eisuke; Kitamura, Tsuyoshi; Kuwabara, Junpei; Ikawa, Satoshi; Yoshizawa, Shunsuke; Shiraki, Kentaro; Kawasaki, Hideya; Arakawa, Ryuichi; Kitano, Katsuhisa

    2014-07-01

    Plasma medicine is an attractive new research area, but the principles of plasma modification of biomolecules in aqueous solution remain elusive. In this study, we investigated the chemical effects of atmospheric-pressure cold plasma on 20 naturally occurring amino acids in aqueous solution. High-resolution mass spectrometry revealed that chemical modifications of 14 amino acids were observed after plasma treatment: (i) hydroxylation and nitration of aromatic rings in tyrosine, phenylalanine and tryptophan; (ii) sulfonation and disulfide linkage formation of thiol groups in cysteine; (iii) sulfoxidation of methionine and (iv) amidation and ring-opening of five-membered rings in histidine and proline. A competitive reaction experiment using 20 amino acids demonstrated that sulfur-containing and aromatic amino acids were preferentially decreased by the plasma treatment. These data provide fundamental information for elucidating the mechanism of protein inactivation for biomedical plasma applications.

  5. 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.

  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. Evaluation of amino acids as turfgrass nematicides.

    Science.gov (United States)

    Zhang, Yun; Luc, John E; Crow, William T

    2010-12-01

    Laboratory experiments revealed that DL-methionine, sodium methionate, potassium methionate, and methionine hydroxyl analog at rates of 224 and 448 kg amino acid/ha reduced the number of Belonolaimus longicaudatus mixed life-stages and Meloidogyne incognita J2 in soil, whereas L-threonine and lysine were not effective in reducing the number of either nematode. Futhermore, greenhouse experiments demonstrated that DL-methionine, sodium methionate, potassium methionate, and methionine hydroxyl analog were equally effective against B. longicaudatus at rates of 112, 224, and 448 kg amino acid/ha, and the highest rate (448 kg amino acid/ha) of all amino acids was more effective in reducing the number of B. longicaudatus than the lower rate. However, phytotoxicity was observed on creeping bentgrass (Agrostis palustris) treated with 448 kg amino acid/ha of methionine hydroxyl analog and DL methionine. In addition, in one of two field experiments on bermudagrass (Cynodon dactylon × C. transvaalensis) turf percentage green cover was increased and the number of B. longicaudatus was reduced by 224 kg amino acid/ha of DL-methionine and potassium methionate compared to untreated controls in one of two trials.

  8. 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.

  9. Synthesis of L-2-amino-8-oxodecanoic acid: an amino acid component of apicidins

    OpenAIRE

    Linares de la Morena, María Lourdes; Agejas Chicharro, Francisco Javier; Alajarín Ferrández, Ramón; Vaquero López, Juan José; Álvarez-Builla Gómez, Julio

    2001-01-01

    The synthesis Of L-2-amino-8-oxodecanoic acid (Aoda) is described. This is a rare amino acid component of apicidins, a family of new cyclic tetrapeptides, inhibitors of histone deacetylase. Aoda was synthesised in seven steps from L-glutamic acid along with some derivatives. Universidad de Alcalá Fundación General de la Universidad de Alcalá FEDER

  10. Lactococcal aminotransferases AraT and BcaT are key enzymes for the formation of aroma compounds from amino acids in cheese

    NARCIS (Netherlands)

    Rijnen, L.; Yvon, M.; Kranenburg, van R.; Courtin, P.; Verheul, A.; Chambellon, E.; Smit, G.

    2003-01-01

    Amino acid catabolism plays a major role in cheese aroma development. Previously, we showed that the lactococcal aminotransferases AraT and BcaT initiate the conversion of aromatic amino acids, branched-chain amino acids and methionine to aroma compounds. In this study, we evaluated the importance o

  11. 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 ...

  12. 2-Amino-5-fluorobenzoic acid

    Directory of Open Access Journals (Sweden)

    K. Gunasekaran

    2013-03-01

    Full Text Available In the title compound, C7H6FNO2, the molecule is almost planar (r.m.s. deviation for the non-H atoms = 0.015 Å and an intramolecular N—H...O hydrogen bond closes an S(6 ring. In the crystal, inversion dimers linked by pairs of O—H...O hydrogen bonds generate R22(8 loops. Weak N—H...F hydrogen bonds, short F...F contacts [2.763 (2 Å] and aromatic π–π stacking interactions [centroid–centroid separation = 3.5570 (11 Å] are also observed in the crystal structure.

  13. 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.

  14. 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.

  15. 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...

  16. 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.

  17. 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

  18. 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......-isoxazolyl]propionic acid (AMOA). Using these AMPA receptor ligands as leads, a series of compounds have been developed as tools for further elucidation of the structural requirements for activation and blockade of AMPA receptors. The synthesized compounds have been tested for activity at ionotropic...... excitatory amino acid (EAA) receptors using receptor binding and electrophysiological techniques, and for activity at metabotropic EAA receptors using second messenger assays. Compounds 1 and 4 were essentially inactive. (RS)-2-Amino-3-[3-(2-carboxyethyl)-5-methyl-4-isoxazolyl]propionic acid (ACMP, 2...

  19. Regulation of indole-3-acetic acid biosynthesis by branched-chain amino acids in Enterobacter cloacae UW5.

    Science.gov (United States)

    Parsons, Cassandra V; Harris, Danielle M M; Patten, Cheryl L

    2015-09-01

    The soil bacterium Enterobacter cloacae UW5 produces the rhizosphere signaling molecule indole-3-acetic acid (IAA) via the indolepyruvate pathway. Expression of indolepyruvate decarboxylase, a key pathway enzyme encoded by ipdC, is upregulated by the transcription factor TyrR in response to aromatic amino acids. Some members of the TyrR regulon may also be controlled by branched-chain amino acids and here we show that expression from the ipdC promoter and production of IAA are downregulated by valine, leucine and isoleucine. Regulation of the IAA synthesis pathway by both aromatic and branched-chain amino acids suggests a broader role for this pathway in bacterial physiology, beyond plant interactions.

  20. Cytokines: muscle protein and amino acid metabolism

    DEFF Research Database (Denmark)

    van Hall, Gerrit

    2012-01-01

    raises TNF-α and IL-6 to moderate levels, has only identified IL-6 as a potent cytokine, decreasing systemic amino acid levels and muscle protein metabolism. The marked decrease in circulatory and muscle amino acid concentrations was observed with a concomitant reduction in both the rates of muscle...... protein synthesis and breakdown, that is, reduced turnover with a minor increase in net muscle degradation. Very similar observations have been made in models of acute inflammation, induced by high-dose endotoxin injection. However, these changes were suggested not to be attributed to a direct effect...... 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...

  1. 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.

  2. 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.

  3. Large neutral amino acids in daily practice

    DEFF Research Database (Denmark)

    Ahring, Kirsten Kiær

    2010-01-01

    At the Kennedy Centre for Phenylketonuria, Denmark, large neutral amino acids (LNAAs) are being used to treat adult and adolescent patients who are nonadherent to dietary treatment for phenylketonuria (PKU). At the start of treatment, a patient must undergo dietary analysis and regular blood...... 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...

  4. Microbial degradation of poly(amino acid)s.

    Science.gov (United States)

    Obst, Martin; Steinbüchel, Alexander

    2004-01-01

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

  5. 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...

  6. Amino Acid Formation on Interstellar Dust Particles

    Science.gov (United States)

    Meierhenrich, U. J.; Munoz Caro, G. M.; Barbier, B.; Brack, A.; Thiemann, W.; Goesmann, F.; Rosenbauer, H.

    2003-04-01

    In the dense interstellar medium dust particles accrete ice layers of known molecular composition. In the diffuse interstellar medium these ice layers are subjected to energetic UV-irradiation. Here, photoreactions form complex organic molecules. The interstellar processes were recently successfully simulated in two laboratories. At NASA Ames Research Center three amino acids were detected in interstellar ice analogues [1], contemporaneously, our European team reported on the identification of 16 amino acids therein [2]. Amino acids are the molecular building blocks of proteins in living organisms. The identification of amino acids on the simulated icy surface of interstellar dust particles strongly supports the assumption that the precursor molecules of life were delivered from interstellar and interplanetary space via (micro-) meteorites and/or comets to the earyl Earth. The results shall be verified by the COSAC experiment onboard the ESA cometary mission Rosetta [3]. [1] M.P. Bernstein, J.P. Dworkin, S.A. Sandford, G.W. Cooper, L.J. Allamandola: itshape Nature \\upshape 416 (2002), 401-403. [2] G.M. Muñoz Caro, U.J. Meierhenrich, W.A. Schutte, B. Barbier, A. Arcones Sergovia, H. Rosenbauer, W.H.-P. Thiemann, A. Brack, J.M. Greenberg: itshape Nature \\upshape 416 (2002), 403-406. [3] U. Meierhenrich, W.H.-P. Thiemann, H. Rosenbauer: itshape Chirality \\upshape 11 (1999), 575-582.

  7. 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.

  8. 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.

  9. [Sublicons containing amino acids and nucleotides].

    Science.gov (United States)

    Kaĭmakov, E A

    1979-01-01

    Sublicons have been obtained. Sublicons are threadlike structures appearing during sublimation of frozen solutions of small concentrations, containing racemate mixture of amino acids and nucleotides. It is suggested that close location of chains and their zonal distribution by the section of helix spire forming sublicon wall, should provide the formation of stereohomogenous and complementary successions of biomonomers of different clases.

  10. 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.

  11. 21 CFR 172.320 - Amino acids.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Amino acids. 172.320 Section 172.320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives §...

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

    Directory of Open Access Journals (Sweden)

    Renwu Zhou

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

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

    Science.gov (United States)

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

    2016-01-01

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

  14. Affinity labelling enzymes with esters of aromatic sulfonic acids

    Science.gov (United States)

    Wong, Show-Chu; Shaw, Elliott

    1977-01-01

    Novel esters of aromatic sulfonic acids are disclosed. The specific esters are nitrophenyl p- and m-amidinophenylmethanesulfonate. Also disclosed is a method for specific inactivation of the enzyme, thrombin, employing nitrophenyl p-amidinophenylmethanesulfonate.

  15. Amino acid quality indices of the leaves of Clerodendrum volubile

    Directory of Open Access Journals (Sweden)

    Ochuko Lucky Erukainure

    2016-04-01

    Full Text Available Objective: To evaluate the amino acid profile and quality indices of Clerodendrum volubile (C. volubile leaves. Methods: Dried leaves of C. 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 of C. volubile as a potential source of amino acids in the human diet as portrayed by its amino acids profile and qualities.

  16. Biosynthesis of natural products containing β-amino acids.

    Science.gov (United States)

    Kudo, Fumitaka; Miyanaga, Akimasa; Eguchi, Tadashi

    2014-08-01

    Covering: up to January, 2014. We focus here on β-amino acids as components of complex natural products because the presence of β-amino acids produces structural diversity in natural products and provides characteristic architectures beyond those of ordinary α-L-amino acids, thus generating significant and unique biological functions in nature. In this review, we first survey the known bioactive β-amino acid-containing natural products including nonribosomal peptides, macrolactam polyketides, and nucleoside-β-amino acid hybrids. Next, the biosynthetic enzymes that form β-amino acids from α-amino acids and the de novo synthesis of β-amino acids are summarized. Then, the mechanisms of β-amino acid incorporation into natural products are reviewed. Because it is anticipated that the rational swapping of the β-amino acid moieties with various side chains and stereochemistries by biosynthetic engineering should lead to the creation of novel architectures and bioactive compounds, the accumulation of knowledge regarding β-amino acid-containing natural product biosynthetic machinery could have a significant impact in this field. In addition, genome mining of characteristic β-amino acid biosynthetic genes and unique β-amino acid incorporation machinery could lead to the discovery of new β-amino acid-containing natural products.

  17. 手性氨基酸酰胺催化二乙基锌与芳香醛不对称加成反应%Enantioselective Addition of Diethylzinc to Aromatic Aldehydes Catalyzed by Modular Amino Acids and Phenylethanamine Based Chiral Ligands

    Institute of Scientific and Technical Information of China (English)

    苟绍华; 叶仲斌; 蔡潇潇; 刘曼; 蒋文超

    2012-01-01

    Enantioselective addition of diethylzinc to a series of aromatic aldehydes was developed by chiral ligand (5)-N-(4-methoxyphenethyl)-3-phenyl-2-(tosylamino)propanamide (Id), which was derivatived from a modular amino acids and long chain amine containg OMe. The catalytic system employing 15 mol% of Id without using titanium complex was found to promote the addition of diethylzinc (ZnEt2) to a wide range of aromatic aldehydes with electron-donating and electron-withdrawing substituents, giving up to 87% ee of the corresponding secondary alcohol under mild conditions.%将由磺酰化氨基酸和长链的含甲氧基官能团的胺制备的(S)-N-(4-甲氧基苯乙基)-3-苯基-2-(对甲基苯磺酰胺)丙酰胺(1d)手性配体用于催化二乙基锌与系列芳香醛对映选择性加成反应.15mol%该催化剂能够对含有吸电子基团、供电子基团及不同位阻的芳香醛均有较好的效果,能够在比较温和的条件下获得高达87%ee和中等程度的产率.

  18. Microbial Production of Amino Acid-Related Compounds.

    Science.gov (United States)

    Wendisch, Volker F

    2016-11-22

    Corynebacterium glutamicum is the workhorse of the production of proteinogenic amino acids used in food and feed biotechnology. After more than 50 years of safe amino acid production, C. glutamicum has recently also been engineered for the production of amino acid-derived compounds, which find various applications, e.g., as synthons for the chemical industry in several markets including the polymer market. The amino acid-derived compounds such as non-proteinogenic ω-amino acids, α,ω-diamines, and cyclic or hydroxylated amino acids have similar carbon backbones and functional groups as their amino acid precursors. Decarboxylation of amino acids may yield ω-amino acids such as β-alanine, γ-aminobutyrate, and δ-aminovalerate as well as α,ω-diamines such as putrescine and cadaverine. Since transamination is the final step in several amino acid biosynthesis pathways, 2-keto acids as immediate amino acid precursors are also amenable to production using recombinant C. glutamicum strains. Approaches for metabolic engineering of C. glutamicum for production of amino acid-derived compounds will be described, and where applicable, production from alternative carbon sources or use of genome streamline will be referred to. The excellent large-scale fermentation experience with C. glutamicum offers the possibility that these amino acid-derived speciality products may enter large-volume markets.

  19. Amino acids regulate the intracellular trafficking of the general amino acid permease of Saccharomycescerevisiae.

    Science.gov (United States)

    Chen, Esther J; Kaiser, Chris A

    2002-11-12

    The delivery to the plasma membrane of the general amino acid permease, Gap1p, of Saccharomyces cerevisiae is regulated by the quality of the nitrogen source in the growth medium. In an effort to define how different nitrogen sources control Gap1p sorting, we find that mutations in GDH1 and GLN1 that decrease the flux through the glutamate and glutamine synthesis pathways result in increased Gap1p sorting to the plasma membrane. Conversely, deletion of MKS1, which increases glutamate and glutamine synthesis, decreases Gap1p sorting to the plasma membrane. Glutamate and glutamine are not unusual in their ability to regulate Gap1p sorting, because the addition of all natural amino acids and many amino acid analogs to the growth medium results in increased Gap1p sorting to the vacuole. Importantly, amino acids have the capacity to signal Gap1p sorting to the vacuole regardless of whether they can be used as a source of nitrogen. Finally, we show that rapamycin does not affect Gap1p sorting, indicating that Gap1p sorting is not directly influenced by the TOR pathway. Together, these data show that amino acids are a signal for sorting Gap1p to the vacuole and imply that the nitrogen-regulated Gap1p sorting machinery responds to amino acid-like compounds rather than to the overall nutritional status associated with growth on a particular nitrogen source.

  20. Recent advances in amino acid production by microbial cells.

    Science.gov (United States)

    Hirasawa, Takashi; Shimizu, Hiroshi

    2016-12-01

    Amino acids have been utilized for the production of foods, animal feeds and pharmaceuticals. After the discovery of the glutamic acid-producing bacterium Corynebacterium glutamicum by Japanese researchers, the production of amino acids, which are primary metabolites, has been achieved using various microbial cells as hosts. Recently, metabolic engineering studies on the rational design of amino acid-producing microbial cells have been successfully conducted. Moreover, the technology of systems biology has been applied to metabolic engineering for the creation of amino acid-producing microbial cells. Currently, new technologies including synthetic biology, single-cell analysis, and evolutionary engineering have been utilized to create amino acid-producing microbial cells. In addition, useful compounds from amino acids have been produced by microbial cells. Here, current researches into the metabolic engineering of microbial cells toward production of amino acids and amino acid-related compounds are reviewed.

  1. Biosynthesis of 'essential' amino acids by scleractinian corals.

    Science.gov (United States)

    Fitzgerald, L M; Szmant, A M

    1997-02-15

    Animals rely on their diet for amino acids that they are incapable either of synthesizing or of synthesizing in sufficient quantities to meet metabolic needs. These are the so-called 'essential amino acids'. This set of amino acids is similar among the vertebrates and many of the invertebrates. Previously, no information was available for amino acid synthesis by the most primitive invertebrates, the Cnidaria. The purpose of this study was to examine amino acid synthesis by representative cnidarians within the Order Scleractinia. Three species of zooxanthellate reef coral, Montastraea faveolata, Acropora cervicornis and Porites divaricata, and two species of non-zooxanthellate coral, Tubastrea coccinea and Astrangia poculata, were incubated with 14C-labelled glucose or with the 14C-labelled amino acids glutamic acid, lysine or valine. Radiolabel tracer was followed into protein amino acids. A total of 17 amino acids, including hydroxyproline, were distinguishable by the techniques used. Of these, only threonine was not found radiolabelled in any of the samples. We could not detect tryptophan or cysteine, nor distinguish between the amino acid pairs glutamic acid and glutamine, or aspartic acid and asparagine. Eight amino acids normally considered essential for animals were made by the five corals tested, although some of them were made only in small quantities. These eight amino acids are valine, isoleucine, leucine, tyrosine, phenylalanine histidine, methionine and lysine. The ability of cnidarians to synthesize these amino acids could be yet another indicator of a separate evolutionary history of the cnidarians from the rest of the Metazoa.

  2. Effects of insulin and glucagon on serum amino acid concentrations in liver disease.

    Directory of Open Access Journals (Sweden)

    Watanabe,Akiharu

    1982-12-01

    Full Text Available The effects of insulin and glucagon administration on serum amino acid levels were investigated in patients with severe liver disease, since simultaneous injection of pancreatic hormones has been recently introduced as a therapeutic approach. The changes in serum amino acid concentrations, as observed 3 h after ceasing a 3 h infusion of insulin and glucagon in 500 ml glucose solution, were an elevation of serum branched chain amino acid (BACA levels and of the molar ratio of BCAA/aromatic amino acid (AAA levels in patients with liver cirrhosis. Similar increases of serum BCAA levels during the infusion were also observed in patients with fulminant hepatitis. The results suggest that insulin-glucagon therapy for severe liver disease has no harmful side effects at least with respect to alterations in the serum aminogram.

  3. Amino acids allosterically regulate the thiamine diphosphate-dependent alpha-keto acid decarboxylase from Mycobacterium tuberculosis.

    Science.gov (United States)

    Werther, Tobias; Spinka, Michael; Tittmann, Kai; Schütz, Anja; Golbik, Ralph; Mrestani-Klaus, Carmen; Hübner, Gerhard; König, Stephan

    2008-02-29

    The gene rv0853c from Mycobacterium tuberculosis strain H37Rv codes for a thiamine diphosphate-dependent alpha-keto acid decarboxylase (MtKDC), an enzyme involved in the amino acid degradation via the Ehrlich pathway. Steady state kinetic experiments were performed to determine the substrate specificity of MtKDC. The mycobacterial enzyme was found to convert a broad spectrum of branched-chain and aromatic alpha-keto acids. Stopped-flow kinetics showed that MtKDC is allosterically activated by alpha-keto acids. Even more, we demonstrate that also amino acids are potent activators of this thiamine diphosphate-dependent enzyme. Thus, metabolic flow through the Ehrlich pathway can be directly regulated at the decarboxylation step. The influence of amino acids on MtKDC catalysis was investigated, and implications for other thiamine diphosphate-dependent enzymes are discussed.

  4. 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

  5. Direct amino acid analyses of mozzarella cheese.

    Science.gov (United States)

    Hoskins, M N

    1985-12-01

    The amino acid content of mozzarella (low moisture, part skim milk) and asadero cheeses was determined by the column chromatographic method. Data from the direct analyses of the mozzarella cheeses were compared with the calculated amino acid composition reported in tables in Agriculture Handbook No. 8-1. Phenylalanine and tyrosine contents were found to be higher in the direct analyses than in the calculated data in Handbook No. 8-1 (1.390 gm and 1.127 gm for phenylalanine, and 1.493 gm and 1.249 gm for tyrosine per 100 gm edible portion, respectively). That is of particular concern in the dietary management of phenylketonuria, in which accuracy in computing levels of phenylalanine and tyrosine is essential.

  6. 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.

  7. 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.

  8. 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.

  9. 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.

  10. Amino acids and hydrocarbons approximately 3,800-Myr old in the Isua rocks, southwestern Greenland

    Science.gov (United States)

    Nagy, B.; Engel, M. H.; Zumberge, J. E.; Ogino, H.; Chang, S. Y.

    1981-01-01

    Results of an analysis of amino acids and hydrocarbons found in the Isua banded iron formation, which contains the oldest known rocks on earth, are discussed. Similarities are pointed out between the relative amino acid abundances of the Isua rocks and those of lichens found on their surfaces, and a lack of substantial racemization indicated by the low D/L ratios in the 3800-million year old rock samples is noted. Experimental results showing the possibility of amino acid diffusion from lichens into the rocks are presented. Comparisons of the Isua rock amino acid D/L ratios with those reported for samples from other regions indicates that none of the Isua amino acids are older than a few tens of thousands to a few hundred thousand years. Analyses of the saturated hydrocarbons of the Isua samples reveals no odd carbon number preference, which may indicate antiquity, however laboratory experiments have shown that amino acids and aromatic and saturated aliphatic hydrocarbons could not have survived the metamorphic history of the Isua rocks. The evidence presented thus suggests that the amino acids and hydrocarbons found are not of the age of the sediments.

  11. Heterodimeric l-amino acid oxidase enzymes from Egyptian Cerastes cerastes venom: Purification, biochemical characterization and partial amino acid sequencing

    Directory of Open Access Journals (Sweden)

    A.E. El Hakim

    2015-12-01

    Full Text Available Two l-amino acid oxidase enzyme isoforms, Cc-LAAOI and Cc-LAAOII were purified to apparent homogeneity from Cerastes cerastes venom in a sequential two-step chromatographic protocol including; gel filtration and anion exchange chromatography. The native molecular weights of the isoforms were 115 kDa as determined by gel filtration on calibrated Sephacryl S-200 column, while the monomeric molecular weights of the enzymes were, 60, 56 kDa and 60, 53 kDa for LAAOI and LAAOII, respectively. The tryptic peptides of the two isoforms share high sequence homology with other snake venom l-amino acid oxidases. The optimal pH and temperature values of Cc-LAAOI and Cc-LAAOII were 7.8, 50 °C and 7, 60 °C, respectively. The two isoenzymes were thermally stable up to 70 °C. The Km and Vmax values were 0.67 mM, 0.135 μmol/min for LAAOI and 0.82 mM, 0.087 μmol/min for LAAOII. Both isoenzymes displayed high catalytic preference to long-chain, hydrophobic and aromatic amino acids. The Mn2+ ion markedly increased the LAAO activity for both purified isoforms, while Na+, K+, Ca2+, Mg2+ and Ba2+ ions showed a non-significant increase in the enzymatic activity of both isoforms. Furthermore, Zn2+, Ni2+, Co2+, Cu2+ and AL3+ ions markedly inhibited the LAAOI and LAAOII activities. l-Cysteine and reduced glutathione completely inhibited the LAAO activity of both isoenzymes, whereas, β-mercaptoethanol, O-phenanthroline and PMSF completely inhibited the enzymatic activity of LAAOII. Furthermore, iodoacitic acid inhibited the enzymatic activity of LAAOII by 46% and had no effect on the LAAOI activity.

  12. 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...

  13. 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

  14. Differential diagnosis of (inherited) amino acid metabolism or transport disorders

    NARCIS (Netherlands)

    W. Blom (W.); J.G.M. Huijmans (Jan)

    1992-01-01

    markdownabstract__Abstract__ Disorders of amino acid metabolism or transport are most clearly expressed in urine. Nevertheless the interpretation of abnormalities in urinary amino acid excretion remains difficult. An increase or decrease of almost every amino acid in urine can be due to various eti

  15. Effect of amino acids on the formation of 2-amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) in creatinine/phenylalanine and creatinine/phenylalanine/4-oxo-2-nonenal reaction mixtures.

    Science.gov (United States)

    Zamora, Rosario; Alcón, Esmeralda; Hidalgo, Francisco J

    2013-12-15

    2-Amino-1-methyl-6-phenylimidazo[4,5-b]pyridine (PhIP) formation in mixtures of creatinine, phenylalanine, amino acids and 4-oxo-2-nonenal was studied, to analyse the role of amino acids on the generation of this heterocyclic aromatic amine. When oxidised lipid was absent, cysteine, serine, aspartic acid, threonine, asparagine, tryptophan, tyrosine, proline, and methionine increased significantly (p amino acids produced reactive carbonyls that converted phenylalanine into phenylacetaldehyde as a key step in the formation of PhIP. When oxidised lipid was present, amino acids competed with phenylalanine for the lipid, and amino acid degradation products were formed, among which alpha-keto acids seemed to play a role in these reactions. These results suggest that PhIP can be produced by several alternative reaction pathways from all major food components, including amino acids and lipids, in addition to carbohydrates.

  16. Computational model of abiogenic amino acid condensation to obtain a polar amino acid profile.

    Science.gov (United States)

    Polanco, Carlos; Buhse, Thomas; Samaniego, José Lino; Castañón González, Jorge Alberto; Arias Estrada, Miguel

    2014-01-01

    In accordance with the second law of thermodynamics, the Universe as a whole tends to higher entropy. However, the sequence of far-from-equilibrium events that led to the emergence of life on Earth could have imposed order and complexity during the course of chemical reactions in the so-called primordial soup of life. Hence, we may expect to find characteristic profiles or biases in the prebiotic product mixtures, as for instance among the first amino acids. Seeking to shed light on this hypothesis, we have designed a high performance computer program that simulates the spontaneous formation of the amino acid monomers in closed environments. The program was designed in reference to a prebiotic scenario proposed by Sydney W. Fox. The amino acid abundances and their polarities as the two principal biases were also taken into consideration. We regarded the computational model as exhaustive since 200,000 amino acid dimers were formed by simulation, subsequently expressed in a vector and compared with the corresponding amino acid dimers that were experimentally obtained by Fox. We found a very high similarity between the experimental results and our simulations.

  17. 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.

  18. Radical-cationic gaseous amino acids: a theoretical study.

    Science.gov (United States)

    Sutherland, Kailee N; Mineau, Philippe C; Orlova, Galina

    2007-08-16

    Three major forms of gaseous radical-cationic amino acids (RCAAs), keto (COOH), enolic (C(OH)OH), and zwitterionic (COO(-)), as well as their tautomers, are examined for aliphatic Ala(.+), Pro(.+), and Ser(.+), sulfur-containing Cys(.+), aromatic Trp(.+), Tyr(.+), and Phe(.+), and basic His(.+). The hybrid B3LYP exchange-correlation functional with various basis sets along with the highly correlated CCSD(T) method is used. For all RCAAs considered, the main stabilizing factor is spin delocalization; for His(.+), protonation of the basic side chain is equally important. Minor stabilizing factors are hydrogen bonding and 3e-2c interactions. An efficient spin delocalization along the N-C(alpha)-C(O-)O moiety occurs upon H-transfer from C(alpha) to the carboxylic group to yield the captodative enolic form, which is the lowest-energy isomer for Ala(.+), Pro(.+), Ser(.+), Cys(.+), Tyr(.+), and Phe(.+). This H-transfer occurs in a single step as a 1,3-shift through the sigma-system. For His(.+), the lowest-energy isomer is formed upon H-transfer from C(alpha) to the basic side chain, which results in a keto form, with spin delocalized along the N-C(alpha)-C=O fragment. Trp(.+) is the only RCAA that favors spin delocalization over an aromatic system given the low ionization energy of indole. The lowest-energy isomer of Trp(.+) is a keto form, with no H-transfer.

  19. Neighbor preferences of amino acids and context-dependent effects of amino acid substitutions in human, mouse, and dog.

    Science.gov (United States)

    Fu, Mingchuan; Huang, Zhuoran; Mao, Yuanhui; Tao, Shiheng

    2014-09-10

    Amino acids show apparent propensities toward their neighbors. In addition to preferences of amino acids for their neighborhood context, amino acid substitutions are also considered to be context-dependent. However, context-dependence patterns of amino acid substitutions still remain poorly understood. Using relative entropy, we investigated the neighbor preferences of 20 amino acids and the context-dependent effects of amino acid substitutions with protein sequences in human, mouse, and dog. For 20 amino acids, the highest relative entropy was mostly observed at the nearest adjacent site of either N- or C-terminus except C and G. C showed the highest relative entropy at the third flanking site and periodic pattern was detected at G flanking sites. Furthermore, neighbor preference patterns of amino acids varied greatly in different secondary structures. We then comprehensively investigated the context-dependent effects of amino acid substitutions. Our results showed that nearly half of 380 substitution types were evidently context dependent, and the context-dependent patterns relied on protein secondary structures. Among 20 amino acids, P elicited the greatest effect on amino acid substitutions. The underlying mechanisms of context-dependent effects of amino acid substitutions were possibly mutation bias at a DNA level and natural selection. Our findings may improve secondary structure prediction algorithms and protein design; moreover, this study provided useful information to develop empirical models of protein evolution that consider dependence between residues.

  20. Neighbor Preferences of Amino Acids and Context-Dependent Effects of Amino Acid Substitutions in Human, Mouse, and Dog

    Directory of Open Access Journals (Sweden)

    Mingchuan Fu

    2014-09-01

    Full Text Available Amino acids show apparent propensities toward their neighbors. In addition to preferences of amino acids for their neighborhood context, amino acid substitutions are also considered to be context-dependent. However, context-dependence patterns of amino acid substitutions still remain poorly understood. Using relative entropy, we investigated the neighbor preferences of 20 amino acids and the context-dependent effects of amino acid substitutions with protein sequences in human, mouse, and dog. For 20 amino acids, the highest relative entropy was mostly observed at the nearest adjacent site of either N- or C-terminus except C and G. C showed the highest relative entropy at the third flanking site and periodic pattern was detected at G flanking sites. Furthermore, neighbor preference patterns of amino acids varied greatly in different secondary structures. We then comprehensively investigated the context-dependent effects of amino acid substitutions. Our results showed that nearly half of 380 substitution types were evidently context dependent, and the context-dependent patterns relied on protein secondary structures. Among 20 amino acids, P elicited the greatest effect on amino acid substitutions. The underlying mechanisms of context-dependent effects of amino acid substitutions were possibly mutation bias at a DNA level and natural selection. Our findings may improve secondary structure prediction algorithms and protein design; moreover, this study provided useful information to develop empirical models of protein evolution that consider dependence between residues.

  1. Methanogenic degradation of (amino)aromatic compounds by anaerobic microbial communities

    NARCIS (Netherlands)

    Linkova, Y.V.; Stams, A.J.M.

    2011-01-01

    Degradation of a range of aromatic substrates by anaerobic microbial communities was studied. Active methanogenic microbial communities decomposing aminoaromatic acids and azo dyes into CH4 and CO2 were isolated. Products of primary conversion were found to be 2-hydroxybenzyl and benzyl alcohols gra

  2. [Bound amino acids in local strains of Trichomonas vaginalis].

    Science.gov (United States)

    Tsvetkova, A; Osinovski, E; Vasilevska, M

    1990-01-01

    Amino acid composition of water-soluble and water-insoluble proteins of 8 strains of Tr. vaginalis is studied. 17 amino acids are found in both protein hydrolyzates. Despite the complete coincidence of their qualitative compositions there are reliable differences in the quantitative contents of some amino acids. Differences in the contents of main amino acids of water-soluble proteins of different strains reflect the belonging of the latter to different sero-groups. No reliable differences in the quantitative contents of amino acids of both water-soluble and water-insoluble proteins in strains belonging to one sero-group are recognised.

  3. Characterization of amino acids using Raman spectroscopy

    Science.gov (United States)

    Jenkins, Amanda L.; Larsen, Richard A.; Williams, Timothy B.

    2005-05-01

    A key process in the development of new drugs is elucidation of the interaction between the drug molecule and the target protein. Such knowledge then makes it possible to make systematic structural modifications of the drug molecule to optimize the interaction. Many analytical techniques can be applied to proteins in solution such as circular dichroism, ultraviolet, and fluorescence spectroscopy but these all have limitations. In this paper, we investigate the feasibility of using relatively simple, visible light Raman spectroscopic methods to investigate amino acids and related biopolymers.

  4. Probing the interaction of individual amino acids with inorganic surfaces using atomic force spectroscopy.

    Science.gov (United States)

    Razvag, Yair; Gutkin, Vitaly; Reches, Meital

    2013-08-13

    This article describes single-molecule force spectroscopy measurements of the interaction between individual amino acid residues and inorganic surfaces in an aqueous solution. In each measurement, there is an amino acid residue, lysine, glutamate, phenylalanine, leucine, or glutamine, and each represents a class of amino acids (positively or negatively charged, aromatic, nonpolar, and polar). Force-distance curves measured the interaction of the individual amino acid bound to a silicon atomic force microscope (AFM) tip with a silcon substrate, cut from a single-crystal wafer, or mica. Using this method, we were able to measure low adhesion forces (below 300 pN) and could clearly determine the strength of interactions between the individual amino acid residues and the inorganic substrate. In addition, we observed how changes in the pH and ionic strength of the solution affected the adsorption of the residues to the substrates. Our results pinpoint the important role of hydrophobic interactions among the amino acids and the substrate, where hydrophobic phenylalanine exhibited the strongest adhesion to a silicon substrate. Additionally, electrostatic interactions also contributed to the adsorption of amino acid residues to inorganic substrates. A change in the pH or ionic strength values of the buffer altered the strength of interactions among the amino acids and the substrate. We concluded that the interplay between the hydrophobic forces and electrostatic interactions will determine the strength of adsorption among the amino acids and the surface. Overall, these results contribute to our understanding of the interaction at the organic-inorganic interface. These results may have implications for our perception of the specificity of peptide binding to inorganic surfaces. Consequently, it would possibly lead to a better design of composite materials and devices.

  5. Local softness, softness dipole and polarizabilities of functional groups: application to the side chains of the twenty amino acids

    CERN Document Server

    Krishta, Alisa; Van Alsenoy, Christian; 10.1063/1.3185349

    2010-01-01

    The values of molecular polarizabilities and softnesses of the twenty amino acids were computed ab initio (MP2). By using the iterative Hirshfeld scheme to partition the molecular electronic properties, we demonstrate that the values of the softness of the side chain of the twenty amino acid are clustered in groups reflecting their biochemical classification, namely: aliphatic, basic, acidic, sulfur containing, and aromatic amino acids . The present findings are in agreement with previous results using different approximations and partitioning schemes [P. Senet and F. Aparicio, J. Chem. Phys. 126,145105 (2007)]. In addition, we show that the polarizability of the side chain of an amino acid depends mainly on its number of electrons (reflecting its size) and consequently cannot be used to cluster the amino acids in different biochemical groups, in contrast to the local softness. Our results also demonstrate that the global softness is not simply proportional to the global polarizability in disagreement with th...

  6. 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.

  7. Ribosomal Synthesis of Peptides with Multiple β-Amino Acids.

    Science.gov (United States)

    Fujino, Tomoshige; Goto, Yuki; Suga, Hiroaki; Murakami, Hiroshi

    2016-02-17

    The compatibility of β-amino acids with ribosomal translation was studied for decades, but it has been still unclear whether the ribosome can accept various β-amino acids, and whether the ribosome can introduce multiple β-amino acids in a peptide. In the present study, by using the Escherichia coli reconstituted cell-free translation system with a reprogramed genetic code, we screened β-amino acids that give high single incorporation efficiency and used them to synthesize peptides containing multiple β-amino acids. The experiments of single β-amino acid incorporation into a peptide revealed that 13 β-amino acids are compatible with ribosomal translation. Six of the tested β-amino acids (βhGly, l-βhAla, l-βhGln, l-βhPhg, l-βhMet, and d-βhPhg) showed high incorporation efficiencies, and seven (l-βhLeu, l-βhIle, l-βhAsn, l-βhPhe, l-βhLys, d-βhAla, and d-βhLeu) showed moderate incorporation efficiencies; whereas no full-length peptide was produced using other β-amino acids (l-βhPro, l-βhTrp, and l-βhGlu). Subsequent double-incorporation experiments using β-amino acids with high single incorporation efficiency revealed that elongation of peptides with successive β-amino acids is prohibited. Efficiency of the double-incorporation of the β-amino acids was restored by the insertion of Tyr or Ile between the two β-amino acids. On the basis of these experiments, we also designed mRNA sequences of peptides, and demonstrated the ribosomal synthesis of peptides containing different types of β-amino acids at multiple positions.

  8. 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

  9. Phenylalanine Aminomutase-Catalyzed Addition of Ammonia to Substituted Cinnamic Acids : a Route to Enantiopure alpha- and beta-Amino Acids

    NARCIS (Netherlands)

    Szymanski, Wiktor; Wu, Bian; Weiner, Barbara; de Wildeman, Stefaan; Feringa, B.L.; B. Janssen, Dick

    2009-01-01

    An approach is described for the synthesis of aromatic alpha- and beta-amino acids that Uses phenylalanine aminomutase to catalyze a highly enantioselective addition of ammonia to substituted cinnamic acids. The reaction has a broad scope and yields Substituted alpha- and beta-phenylalanines with ex

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

    OpenAIRE

    Csilla Albert; Gabriella Pohn; Katalin Lóki; Szidónia Salamon; Beáta Albert; P. Sára; Z. Mándoki; Jánosné Csapó; Csapó, J.

    2007-01-01

    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 particula...

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

    Science.gov (United States)

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

    2012-10-01

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

  12. 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.

  13. Formation and transformation of amino acids and amino acid precursors by high-velocity impacts

    Science.gov (United States)

    Kaneko, T.; Kobayashi, K.; Yamori, A.

    A wide variety of organic compounds have been found in extraterrestrial bodies such as comets and carbonaceous chondrites. It is plausible that these extraterrestrial bodies carried organic compounds such as amino acids or their precursors to the early Earth. It is claimed, however, that these extraterrestrial organics were destroyed during impacts to the Earth. We therefore examined possible transformation of amino acids and their precursors during high-velocity impacts by using a rail gun "HYPAC" in ISAS. Starting materials used in the impact experiments were (i) aqueous solution of glycine (10 mM or 1.0 M), and (ii) a mixture of ammonia, methanol and water. The target materials were sealed in stainless steel capsules, and shocked by impact with a polycarbonate projectile accelerated with "HYPAC" to the velocities of 2.5 - 7.0 km/s. A part of the products was acid-hydrolyzed. Both hydrolyzed an unhydrolyzed products were analyzed by mass spectrometry, high performance liquid chromatography and capillary electrophoresis and chromatography. When an aqueous solution containing ammonia, methanol and water was shocked by impact at the velocity of 6.4 km/s, a number of amino acids (e.g., serine and glycine) were detected after hydrolysis. The present results suggest that amino acid precursors could be formed during cometary impacts. When glycine solution was used as a starting material, about 40 % of glycine was recovered even after 6 km/s impact. Methylamine and ammonia, which are known as pyrolytic products of glycine, were detected, besides them, diketopiperazine and an unidentified product whose molecular weight was 134, were detected, while no glycine peptides were identified in them. It was shown that the impact processes resulted in the formation of amino acid condensates. Thermal stability of glycine precursor is comparable with glycine. The present results suggest that organic material could survive and/or formed during an impact process. Most of organic

  14. Inadequacy of prebiotic synthesis as origin of proteinous amino acids.

    Science.gov (United States)

    Wong, J T; Bronskill, P M

    1979-07-18

    The production of some nonproteinous, and lack of production of other proteinous, amino acids in model prebiotic synthesis, along with the instability of glutamine and asparagine, suggest that not all of the 20 present day proteinous amino acids gained entry into proteins directly from the primordial soup. Instead, a process of active co-evolution of the genetic code and its constituent amino acids would have to precede the final selection of these proteinous amono acids.

  15. Development of N-ferrocenyl(benzoyl)amino-acid esters stationary phase for high performance liquid chromatography.

    Science.gov (United States)

    Zhou, Xiaohua; Li, Xiaole; Cao, Aijuan; Lijun, Qiao; Yu, Ajuan; Zhang, Shusheng; Wu, Yangjie

    2015-11-01

    A new stationary phase for high-performance liquid chromatography was prepared by covalently bonding N-ferrocenyl(benzoyl)amino-acid esters (L(1)) onto silica gel using 3-aminopropyltriethoxysilane as coupling reagent. The structure of new material was characterized by infrared spectroscopy, elemental analysis and thermogravimetric analysis. The chromatographic behavior of the phase was illustrated in reversed-phase (RP) and normal-phase (NP) modes using polycyclic aromatic hydrocarbons (PAHs), aromatics positional isomers, amines, 5-nitroimidazoles, organophosphorus pesticides and phenols as probes. Multiple mechanisms including hydrophobic, hydrogen bonding, π-π, dipole-dipole, charge-transfer and acid-base equilibrium interactions are involved. Thus, multi-interaction mechanisms and mixed-mode separation of the new phase can very likely guarantee its excellent chromatographic performance for the analysis of complex samples. The L(1) AminoSil column was successfully employed for the analysis of organophosphorus pesticides in vegetable.

  16. 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.

  17. The prebiotic synthesis of amino acids - interstellar vs. atmospheric mechanisms

    Science.gov (United States)

    Meierhenrich, U. J.; Muñoz Caro, G. M.; Schutte, W. A.; Barbier, B.; Arcones Segovia, A.; Rosenbauer, H.; Thiemann, W. H.-P.; Brack, A.

    2002-11-01

    Until very recently, prebiotic amino acids were believed to have been generated in the atmosphere of the early Earth, as successfully simulated by the Urey-Miller experiments. Two independent studies now identified ice photochemistry in the interstellar medium as a possible source of prebiotic amino acids. Ultraviolet irradiation of ice mixtures containing identified interstellar molecules (such as H2O, CO2, CO, CH3OH, and NH3) in the conditions of vacuum and low temperature found in the interstellar medium generated amino acid structures including glycine, alanine, serine, valine, proline, and aspartic acid. After warmup, hydrolysis and derivatization, our team was able to identify 16 amino acids as well as furans and pyrroles. Enantioselective analyses of the amino acids showed racemic mixtures. A prebiotic interstellar origin of amino acid structures is now discussed to be a plausible alternative to the Urey-Miller mechanism.

  18. Transfer of Asymmetry between Proteinogenic Amino Acids under Harsh Conditions.

    Science.gov (United States)

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

    2017-03-31

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

  19. Synthesis and biological evaluation of new salvinorin A analogues incorporating natural amino acids.

    Science.gov (United States)

    Fichna, Jakub; Lewellyn, Kevin; Yan, Feng; Roth, Bryan L; Zjawiony, Jordan K

    2011-01-01

    The synthesis and in vitro evaluation of a new series of salvinorin A analogues substituted at the C(2) position with natural amino acids is reported. Compound 12, containing Val, displayed high affinity and full agonist activity at the kappa-opioid receptor. Analogues with bulky and/or aromatic residues were inactive, showing the importance of size and electronegativity of C(2)-substituents for binding affinity of salvinorin A derivatives.

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

    Science.gov (United States)

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

    2015-01-12

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

  1. 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.

  2. 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.

  3. Twenty natural amino acids identification by a photochromic sensor chip.

    Science.gov (United States)

    Qin, Meng; Li, Fengyu; Huang, Yu; Ran, Wei; Han, Dong; Song, Yanlin

    2015-01-20

    All 20 natural amino acids identification shows crucial importance in biochemistry and clinical application while it is still a challenge due to highly similarity in molecular configuration of the amino acids. Low efficiency, complicated sensing molecules and environment hindered the successful identification. Here, we developed a facile sensor chip composed of one photochromic molecule with metal ions spotted to form spirooxazine-metallic complexes, and successfully recognized all the 20 natural amino acids as well as their mixtures. The sensor chip gives distinct fluorescent fingerprint pattern of each amino acid, based on multistate of spirooxazine under different light stimulations and discriminated interaction between various metal ions and amino acids. The sensor chip demonstrates powerful capability of amino acids identification, which promotes sensing of biomolecules.

  4. Modulatory Effects of Dietary Amino Acids on Neurodegenerative Diseases.

    Science.gov (United States)

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

    2016-01-01

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

  5. Surface Propensity of Atmospherically Relevant Amino Acids Studied by XPS.

    Science.gov (United States)

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

    2017-03-30

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

  6. Distribution and Origin of Amino Acids in Lunar Regolith Samples

    Science.gov (United States)

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

    2015-01-01

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

  7. 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.

  8. Preference for and learning of amino acids in larval Drosophila

    Directory of Open Access Journals (Sweden)

    Nana Kudow

    2017-03-01

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

  9. Preference for and learning of amino acids in larval Drosophila.

    Science.gov (United States)

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

    2017-03-15

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

  10. 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.

  11. Evolution of the biosynthesis of the branched-chain amino acids

    Science.gov (United States)

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

    1995-06-01

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

  12. Evolution of the biosynthesis of the branched-chain amino acids

    Science.gov (United States)

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

    1995-01-01

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

  13. 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 ...

  14. SIFT: predicting amino acid changes that affect protein function

    OpenAIRE

    Ng, Pauline C.; Henikoff, Steven

    2003-01-01

    Single nucleotide polymorphism (SNP) studies and random mutagenesis projects identify amino acid substitutions in protein-coding regions. Each substitution has the potential to affect protein function. SIFT (Sorting Intolerant From Tolerant) is a program that predicts whether an amino acid substitution affects protein function so that users can prioritize substitutions for further study. We have shown that SIFT can distinguish between functionally neutral and deleterious amino acid changes in...

  15. 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.

  16. 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

  17. Mycosporine-like amino acids from coral dinoflagellates.

    Science.gov (United States)

    Rosic, Nedeljka N; Dove, Sophie

    2011-12-01

    Coral reefs are one of the most important marine ecosystems, providing habitat for approximately a quarter of all marine organisms. Within the foundation of this ecosystem, reef-building corals form mutualistic symbioses with unicellular photosynthetic dinoflagellates of the genus Symbiodinium. Exposure to UV radiation (UVR) (280 to 400 nm) especially when combined with thermal stress has been recognized as an important abiotic factor leading to the loss of algal symbionts from coral tissue and/or a reduction in their pigment concentration and coral bleaching. UVR may damage biological macromolecules, increase the level of mutagenesis in cells, and destabilize the symbiosis between the coral host and their dinoflagellate symbionts. In nature, corals and other marine organisms are protected from harmful UVR through several important photoprotective mechanisms that include the synthesis of UV-absorbing compounds such as mycosporine-like amino acids (MAAs). MAAs are small (<400-Da), colorless, water-soluble compounds made of a cyclohexenone or cyclohexenimine chromophore that is bound to an amino acid residue or its imino alcohol. These secondary metabolites are natural biological sunscreens characterized by a maximum absorbance in the UVA and UVB ranges of 310 to 362 nm. In addition to their photoprotective role, MAAs act as antioxidants scavenging reactive oxygen species (ROS) and suppressing singlet oxygen-induced damage. It has been proposed that MAAs are synthesized during the first part of the shikimate pathway, and recently, it has been suggested that they are synthesized in the pentose phosphate pathway. The shikimate pathway is not found in animals, but in plants and microbes, it connects the metabolism of carbohydrates to the biosynthesis of aromatic compounds. However, both the complete enzymatic pathway of MAA synthesis and the extent of their regulation by environmental conditions are not known. This minireview discusses the current knowledge of MAA

  18. 40 CFR 721.9620 - Aromatic sulfonic acid compound with amine.

    Science.gov (United States)

    2010-07-01

    ... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Aromatic sulfonic acid compound with... Specific Chemical Substances § 721.9620 Aromatic sulfonic acid compound with amine. (a) Chemical substance... aromatic sulfonic acid compound with amine (PMN P-93-832) is subject to reporting under this section...

  19. Amino Acid transport in protoplasts isolated from soybean leaves.

    Science.gov (United States)

    Vernooy, C D; Lin, W

    1986-05-01

    We isolated large quantities of mesophyll protoplasts from source and sink leaves of soybean plants and examined them for amino acid uptake. Accumulation of amino acids in isolated protoplasts was linear for at least 40 minutes. Uptake kinetics revealed the presence of both saturable and linear components. Increasing external pH decreases the uptake. The uncoupler, carbonyl cyanide p-trifluoromethoxyphenylhydrazone at 15 micromolar inhibited and fusicoccin at 10 micromolar stimulated amino acid uptake. Our data are consistent with a proton-cotransport mechanism for the uptake of l-glutamine and alpha-amino isobutyric acid into soybean mesophyll cells.

  20. 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.

  1. 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.

  2. 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...

  3. Propensity of salicylamide and ethenzamide cocrystallization with aromatic carboxylic acids.

    Science.gov (United States)

    Przybyłek, Maciej; Ziółkowska, Dorota; Mroczyńska, Karina; Cysewski, Piotr

    2016-03-31

    The cocrystallization of salicylamide (2-hydroxybenzamide, SMD) and ethenzamide (2-ethoxybenzamide, EMD) with aromatic carboxylic acids was examined both experimentally and theoretically. The supramolecular synthesis taking advantage of the droplet evaporative crystallization (DEC) technique was combined with powder diffraction and vibrational spectroscopy as the analytical tools. This led to identification of eleven new cocrystals including pharmaceutically relevant coformers such as mono- and dihydroxybenzoic acids. The cocrystallization abilities of SMD and EMD with aromatic carboxylic acids were found to be unexpectedly divers despite high formal similarities of these two benzamides and ability of the R2,2(8) heterosynthon formation. The source of diversities of the cocrystallization landscapes is the difference in the stabilization of possible conformers by adopting alternative intramolecular hydrogen boding patterns. The stronger intramolecular hydrogen bonding the weaker affinity toward intermolecular complexation potential. The substituent effects on R2,2(8) heterosynthon properties are also discussed.

  4. 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.

  5. 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.

  6. 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.

  7. Synthesis, photophysical properties of triazolyl-donor/acceptor chromophores decorated unnatural amino acids: Incorporation of a pair into Leu-enkephalin peptide and application of triazolylperylene amino acid in sensing BSA.

    Science.gov (United States)

    Bag, Subhendu Sekhar; Jana, Subhashis; Pradhan, Manoj Kumar

    2016-08-15

    The research in the field of design and synthesis of unnatural amino acids is growing at a fast space for the increasing demand of proteins of potential therapeutics and many other diversified novel functional applications. Thus, we report herein the design and synthesis of microenvironment sensitive fluorescent triazolyl unnatural amino acids (UNAA) decorated with donor and/or acceptor aromatic chromophores via click chemistry. The synthesized fluorescent amino acids show interesting solvatochromic characteristic and/or intramolecular charge transfer (ICT) feature as is revealed from the UV-visible, fluorescence photophysical properties and DFT/TDDFT calculation. HOMO-LUMO distribution shows that the emissive states of some of the amino acids are characterized with more significant electron redistribution between the triazolyl moiety and the aromatic chromophores linked to it leading to modulated emission property. A pair of donor-acceptor amino acid shows interesting photophysical interaction property indicating a FRET quenching event. Furthermore, one of the amino acid, triazolyl-perylene amino acid, has been exploited for studying interaction with BSA and found that it is able to sense BSA with an enhancement of fluorescence intensity. Finally, we incorporated a pair of donor/acceptor amino acids into a Leu-enkephalin analogue pentapeptide which was found to adopt predominantly type II β-turn conformation. We envisage that our investigation is of importance for the development of new fluorescent donor-acceptor unnatural amino acids a pair of which can be exploited for generating fluorescent peptidomimetic probe of interesting photophysical property for applications in studying peptide-protein interaction.

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

    Science.gov (United States)

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

    2009-10-16

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

  9. 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.

  10. Sodium borohydride reduction of aromatic carboxylic acids via methyl esters

    Indian Academy of Sciences (India)

    Aamer Saeed; Zaman Ashraf

    2006-09-01

    A number of important aromatic carboxylic acids precursors, or intermediates in the syntheses of natural products, are converted into methyl esters and reduced to the corresponding primary alcohols using a sodium borohydride-THF-methanol system. The alcohols are obtained in 70-92% yields in 2-5 hours, in a pure state. This two-step procedure not only provides a better alternative to aluminum hydride reduction of acids but also allows the selective reduction of esters in presence of acids, amides, nitriles or nitro functions which are not affected under these conditions.

  11. 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.

  12. Gas-phase Acidities of Aspartic Acid, Glutamic Acid, and their Amino Acid Amides.

    Energy Technology Data Exchange (ETDEWEB)

    Li, Zhong; Matus, Myrna H; Velazquez, Hector A; Dixon, David A; Cassady, Carolyn J

    2007-02-14

    Gas-phase acidities (GA or ΔGacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage’s importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3–4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  13. Vibrational and photoionization spectroscopy of biomolecules: aliphatic amino acid structures.

    Science.gov (United States)

    Hu, Yongjun; Bernstein, Elliot R

    2008-04-28

    The aliphatic amino acids glycine, valine, leucine, and isoleucine are thermally placed into the gas phase and expanded into a vacuum system for access by time of flight mass spectroscopy and infrared (IR) spectroscopy in the energy range of 2500-4000 cm(-1) (CH, NH, OH, and stretching vibrations). The isolated neutral amino acids are ionized by a single photon of 10.5 eV energy (118 nm), which exceeds by less than 2 eV their reported ionization thresholds. As has been reported for many hydrogen bonded acid-base systems (e.g., water, ammonia, alcohol, acid clusters, and acid molecules), the amino acids undergo a structural rearrangement in the ion state (e.g., in simplest form, a proton transfer) that imparts sufficient excess vibrational energy to the ion to completely fragment it. No parent ions are observed. If the neutral ground state amino acids are exposed to IR radiation prior to ionization, an IR spectrum of the individual isomers for each amino acid can be determined by observation of the ion intensity of the different fragment mass channels. Both the IR spectrum and fragmentation patterns for individual isomers can be qualitatively identified and related to a particular isomer in each instance. Thus, each fragment ion detected presents an IR spectrum of its particular parent amino acid isomer. In some instances, the absorption of IR radiation by the neutral amino acid parent isomer increases a particular fragmentation mass channel intensity, while other fragmentation mass channel intensities decrease. This phenomenon can be rationalized by considering that with added energy in the molecule, the fragmentation channel populations can be modulated by the added vibrational energy in the rearranged ions. This observation also suggests that the IR absorption does not induce isomerization in the ground electronic state of these amino acids. These data are consistent with theoretical predictions for isolated amino acid secondary structures and can be related to

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

    Science.gov (United States)

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

    2014-05-16

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

  15. 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.

  16. Polysulfone affinity membranes for the treatment of amino acid mixtures.

    Science.gov (United States)

    Rodemann, K; Staude, E

    1995-06-20

    Affinity membranes for the treatment of solutions containing amino acids were obtained via lithiating polysulfone that was subsequently converted with glycidylether. From this polymer asymmetric ultrafiltration membranes were cast. The membranes were reacted with iminodiacetic acid yielding membranes fitted out with bidentate chelates. The same reaction path was applied to commercially available symmetric microfiltration membranes. The chelate-bearing membranes were complexed with Cu, Ni, and Zn ions. For the experiments with amino acids only the Cu-complexed membranes were used. The complexation constants for histidine and tryptophan for six different membranes were determined. Because of the affinity of these two amino acids for the complexed Cu ions, they could easily be separated from solutions containing amino acids such as alanine, glycine, and valine. Also, concentrating very dilute amino acid solutions was carried out successfully.

  17. Synthesis of gold nanoparticles using various amino acids.

    Science.gov (United States)

    Maruyama, Tatsuo; Fujimoto, Yuhei; Maekawa, Tetsuya

    2015-06-01

    Gold nanoparticles (4-7nm) were synthesized from tetraauric acid using various amino acids as reducing and capping agents. The gold nanoparticles were produced from the incubation of a AuCl4(-) solution with an amino acid at 80°C for 20min. Among the twenty amino acids tested, several amino acids produced gold nanoparticles. The color of the nanoparticle solutions varied with the amino acids used for the reduction. We adopted l-histidine as a reducing agent and investigated the effects of the synthesis conditions on the gold nanoparticles. The His and AuCl4(-) concentrations affected the size of the gold nanoparticles and their aggregates. The pH of the reaction solution also affected the reaction yields and the shape of the gold nanoparticles.

  18. Free amino acids in botanicals and botanical preparations.

    Science.gov (United States)

    Carratù, B; Boniglia, C; Giammarioli, S; Mosca, M; Sanzini, E

    2008-06-01

    Numerous studies were carried out about aminoacidic composition of vegetable proteins, but information about the free amino acid pool and the role of these substances is very incomplete. The aim of this paper was to contribute to the scarce knowledge concerning the composition of free amino acids in botanicals and botanical preparations widely used as food, in dietary supplements, and in pharmaceutical products. This work studied the composition of free amino acids, identified the major components of 19 species of plants, and evaluated the influence of different types of extraction on the amino acid profile. Amino acids were determined using an automatic precolumn derivatization with fluorenylmethyl-chloroformate and reversed-phase liquid chromatography with fluorescence and ultraviolet detection. The amounts of total free amino acids varied widely between plants, from approximately 12 g in 100 g of Echinacea pallida extract to less than 60 mg in the same amount of Coleus forskohlii, Garcinia cambogia, and Glycine max. In 13 plants arginine, asparagine, glutamine, proline, and gamma-aminobutyric acid were the free amino acids found in preponderant quantities. The levels of free amino acids above the quantification limit in 36 assayed samples of botanicals, extracts, and supplements are shown.

  19. Silver-catalyzed arylation of (hetero)arenes by oxidative decarboxylation of aromatic carboxylic acids.

    Science.gov (United States)

    Kan, Jian; Huang, Shijun; Lin, Jin; Zhang, Min; Su, Weiping

    2015-02-09

    A long-standing challenge in Minisci reactions is achieving the arylation of heteroarenes by oxidative decarboxylation of aromatic carboxylic acids. To address this challenge, the silver-catalyzed intermolecular Minisci reaction of aromatic carboxylic acids was developed. With an inexpensive silver salt as a catalyst, this new reaction enables a variety of aromatic carboxylic acids to undergo decarboxylative coupling with electron-deficient arenes or heteroarenes regardless of the position of the substituents on the aromatic carboxylic acid, thus eliminating the need for ortho-substituted aromatic carboxylic acids, which were a limitation of previously reported methods.

  20. Enzymatic tRNA acylation by acid and alpha-hydroxy acid analogues of amino acids.

    Science.gov (United States)

    Owczarek, Alina; Safro, Mark; Wolfson, Alexey D

    2008-01-08

    Incorporation of unnatural amino acids with unique chemical functionalities has proven to be a valuable tool for expansion of the functional repertoire and properties of proteins as well as for structure-function analysis. Incorporation of alpha-hydroxy acids (primary amino group is substituted with hydroxyl) leads to the synthesis of proteins with peptide bonds being substituted by ester bonds. Practical application of this modification is limited by the necessity to prepare corresponding acylated tRNA by chemical synthesis. We investigated the possibility of enzymatic incorporation of alpha-hydroxy acid and acid analogues (lacking amino group) of amino acids into tRNA using aminoacyl-tRNA synthetases (aaRSs). We studied direct acylation of tRNAs by alpha-hydroxy acid and acid analogues of amino acids and corresponding chemically synthesized analogues of aminoacyl-adenylates. Using adenylate analogues we were able to enzymatically acylate tRNA with amino acid analogues which were otherwise completely inactive in direct aminoacylation reaction, thus bypassing the natural mechanisms ensuring the selectivity of tRNA aminoacylation. Our results are the first demonstration that the use of synthetic aminoacyl-adenylates as substrates in tRNA aminoacylation reaction may provide a way for incorporation of unnatural amino acids into tRNA, and consequently into proteins.

  1. Ammonia and amino acid profiles in liver cirrhosis: effects of variables leading to hepatic encephalopathy.

    Science.gov (United States)

    Holecek, Milan

    2015-01-01

    Hyperammonemia and severe amino acid imbalances play central role in hepatic encephalopathy (HE). In the article is demonstrated that the main source of ammonia in cirrhotic subjects is activated breakdown of glutamine (GLN) in enterocytes and the kidneys and the main source of GLN is ammonia detoxification to GLN in the brain and skeletal muscle. Branched-chain amino acids (BCAA; valine, leucine, and isoleucine) decrease due to activated GLN synthesis in muscle. Aromatic amino acids (AAA; phenylalanine, tyrosine, and tryptophan) and methionine increase due to portosystemic shunts and reduced ability of diseased liver. The effects on aminoacidemia of the following variables that may affect the course of liver disease are discussed: nutritional status, starvation, protein intake, inflammation, acute hepatocellular damage, bleeding from varices, portosystemic shunts, hepatic cancer, and renal failure. It is concluded that (1) neither ammonia nor amino acid concentrations correlate closely with the severity of liver disease; (2) BCAA/AAA ratio could be used as a good index of liver impairment and for early detection of derangements in amino acid metabolism; (3) variables potentially leading to overt encephalopathy exert substantial but uneven effects; and (4) careful monitoring of ammonia and aminoacidemia may discover important break points in the course of liver disease and indicate appropriate therapeutic approach. Of special importance might be isoleucine deficiency in bleeding from varices, arginine deficiency in sepsis, and a marked rise of GLN and ammonia levels that may appear in all events leading to HE.

  2. Gas-phase acidities of aspartic acid, glutamic acid, and their amino acid amides

    Science.gov (United States)

    Li, Zhong; Matus, Myrna H.; Velazquez, Hector Adam; Dixon, David A.; Cassady, Carolyn J.

    2007-09-01

    Gas-phase acidities (GA or [Delta]Gacid) for the two most acidic common amino acids, aspartic acid and glutamic acid, have been determined for the first time. Because of the amide linkage's importance in peptides and as an aid in studying side chain versus main chain deprotonation, aspartic acid amide and glutamic acid amide were also studied. Experimental GA values were measured by proton transfer reactions in an electrospray ionization/Fourier transform ion cyclotron resonance mass spectrometer. Calculated GAs were obtained by density functional and molecular orbital theory approaches. The best agreement with experiment was found at the G3MP2 level; the MP2/CBS and B3LYP/aug-cc-pVDZ results are 3-4 kcal/mol more acidic than the G3MP2 results. Experiment shows that aspartic acid is more acidic than glutamic acid by ca. 3 kcal/mol whereas the G3MP2 results show a smaller acidity difference of 0.2 kcal/mol. Similarly, aspartic acid amide is experimentally observed to be ca. 2 kcal/mol more acidic than glutamic acid amide whereas the G3MP2 results show a correspondingly smaller energy difference of 0.7 kcal/mol. The computational results clearly show that the anions are all ring-like structures with strong hydrogen bonds between the OH or NH2 groups and the CO2- group from which the proton is removed. The two amino acids are main-chain deprotonated. In addition, use of the COSMO model for the prediction of the free energy differences in aqueous solution gave values in excellent agreement with the most recent experimental values for pKa. Glutamic acid is predicted to be more acidic than aspartic acid in aqueous solution due to differential solvation effects.

  3. 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.

  4. Selective production of aromatics from alkylfurans over solid acid catalysts

    DEFF Research Database (Denmark)

    Wang, Dong; Dumesic, James A.; Taarning, Esben

    2013-01-01

    Solid acid catalysts were studied at temperatures near 523K for the production of benzene, toluene, and p-xylene by the reaction of ethylene with furan, 2-methylfuran, and 2,5-dimethylfuran, respectively, through the combination of cycloaddition and dehydrative aromatization reactions. Catalysts ...... that the high reactivity of WOx-ZrO2 is mainly associated with the presence of subnanometer WOx clusters mixed with zirconium, which reach a maximum surface concentration at intermediate tungsten coverage....

  5. A unique dual activity amino acid hydroxylase in Toxoplasma gondii.

    Directory of Open Access Journals (Sweden)

    Elizabeth A Gaskell

    Full Text Available The genome of the protozoan parasite Toxoplasma gondii was found to contain two genes encoding tyrosine hydroxylase; that produces L-DOPA. The encoded enzymes metabolize phenylalanine as well as tyrosine with substrate preference for tyrosine. Thus the enzymes catabolize phenylalanine to tyrosine and tyrosine to L-DOPA. The catalytic domain descriptive of this class of enzymes is conserved with the parasite enzyme and exhibits similar kinetic properties to metazoan tyrosine hydroxylases, but contains a unique N-terminal extension with a signal sequence motif. One of the genes, TgAaaH1, is constitutively expressed while the other gene, TgAaaH2, is induced during formation of the bradyzoites of the cyst stages of the life cycle. This is the first description of an aromatic amino acid hydroxylase in an apicomplexan parasite. Extensive searching of apicomplexan genome sequences revealed an ortholog in Neospora caninum but not in Eimeria, Cryptosporidium, Theileria, or Plasmodium. Possible role(s of these bi-functional enzymes during host infection are discussed.

  6. 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...

  7. 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....

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

    DEFF Research Database (Denmark)

    Andersen, C.A.F.; Brunak, Søren

    2004-01-01

    -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...

  9. Origin of Homochirality of Amino Acids in the Biosphere

    Directory of Open Access Journals (Sweden)

    Shosuke Kojo

    2010-05-01

    Full Text Available Discussions are made concerning realistic mechanisms for the origin of L-amino acids in the biosphere. As the most plausible mechanism, it is proposed that a mixture of racemic amino acids in the prebiotic sea caused spontaneous and effective optical resolution through self crystallization, even if asymmetric synthesis of a single amino acid has never occurred without the aid of an optically active molecule. This hypothesis is based on recrystallization of a mixture of D,L-amino acids in the presence of excess of D,L-asparagine (Asn. The enantiomeric excess (ee of each amino acid in the resulting crystals indicates that crystallization of co-existing amino acids with the configuration same as that of Asn took place, although it was incidental whether the enrichment occurred in L- or D-amino acids. In addition, the resulting ee was sufficiently high (up to 100% to account for the predominance of L-amino acids on the earth.

  10. 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

  11. 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

  12. Amino acid determination in some edible Mexican insects.

    Science.gov (United States)

    Ladrón de Guevara, O; Padilla, P; García, L; Pino, J M; Ramos-Elorduy, J

    1995-06-01

    The amino acid contents of edible insects from different provinces of Mexico and reference proteins were analysed by reversed-phase high-performance liquid chromatography and ion exchange chromatography. The insect amino acid contents were higher than the adult requirements indicated by the WHO/FAO pattern.

  13. 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

  14. Site specific incorporation of keto amino acids into proteins

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter G [La Jolla, CA; Wang, Lei [San Diego, CA

    2012-02-14

    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.

  15. Site specific incorporation of keto amino acids into proteins

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter G. (La Jolla, CA); Wang, Lei (San Diego, CA)

    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.

  16. Site specific incorporation of keto amino acids into proteins

    Energy Technology Data Exchange (ETDEWEB)

    Schultz, Peter G [La Jolla, CA; Wang, Lei [San Diego, CA

    2011-12-06

    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.

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

    Science.gov (United States)

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

    2008-12-01

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

  18. Amino acids: metabolism, functions, and nutrition.

    Science.gov (United States)

    Wu, Guoyao

    2009-05-01

    Recent years have witnessed the discovery that amino acids (AA) are not only cell signaling molecules but are also regulators of gene expression and the protein phosphorylation cascade. Additionally, AA are key precursors for syntheses of hormones and low-molecular weight nitrogenous substances with each having enormous biological importance. Physiological concentrations of AA and their metabolites (e.g., nitric oxide, polyamines, glutathione, taurine, thyroid hormones, and serotonin) are required for the functions. However, elevated levels of AA and their products (e.g., ammonia, homocysteine, and asymmetric dimethylarginine) are pathogenic factors for neurological disorders, oxidative stress, and cardiovascular disease. Thus, an optimal balance among AA in the diet and circulation is crucial for whole body homeostasis. There is growing recognition that besides their role as building blocks of proteins and polypeptides, some AA regulate key metabolic pathways that are necessary for maintenance, growth, reproduction, and immunity. They are called functional AA, which include arginine, cysteine, glutamine, leucine, proline, and tryptophan. Dietary supplementation with one or a mixture of these AA may be beneficial for (1) ameliorating health problems at various stages of the life cycle (e.g., fetal growth restriction, neonatal morbidity and mortality, weaning-associated intestinal dysfunction and wasting syndrome, obesity, diabetes, cardiovascular disease, the metabolic syndrome, and infertility); (2) optimizing efficiency of metabolic transformations to enhance muscle growth, milk production, egg and meat quality and athletic performance, while preventing excess fat deposition and reducing adiposity. Thus, AA have important functions in both nutrition and health.

  19. 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).

  20. Amino Acid Analyses of Acid Hydrolysates in Desert Varnish

    Science.gov (United States)

    Perry, Randall S.; Staley, James T.; Dworkin, Jason P.; Engel, Mike

    2001-01-01

    There has long been a debate as to whether rock varnish deposits are microbially mediated or are deposited by inorganic processes. Varnished rocks are found throughout the world primarily in arid and semi-arid regions. The varnish coats are typically up to 200 microns thick and are composed of clays and alternating layers enriched in manganese and iron oxides. The individual layers range in thickness from 1 micron to greater than 10 microns and may continue laterally for more than a 100 microns. Overlapping botryoidal structures are visible in thin section and scanning electron micrographs. The coatings also include small amounts of organic mater and detrital grains. Amino-acid hydrolysates offer a means of assessing the organic composition of rock varnish collected from the Sonoran Desert, near Phoenix, AZ. Chromatographic analyses of hydrolysates from powdered samples of rock varnish suggest that the interior of rock varnish is relatively enriched in amino acids and specifically in d-alanine and glutamic acid. Peptidoglycan (murein) is the main structural component of gram-positive bacterial cell walls. The d-enantiomer of alanine and glutamic acid are specific to peptidoglycan and are consequently an indicator for the presence of bacteria. D-alanine is also found in teichoic acid which is only found in gram-positive bacteria. Several researchers have cultured bacteria from the surface of rock varnish and most have been gram-positive, suggesting that gram-positive bacteria are intimately associated with varnish coatings and may play a role in the formation of varnish coatings.

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

    Science.gov (United States)

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

    1983-01-01

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

  2. 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.

  3. 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...... carbon (%TAAC: 7-14%) and total nitrogen (%TAAN: 23-38%) in surface sediments decreased with increasing water depth (from 126 to 1350 m) indicating that organic matter becomes increasingly decomposed in surface sediments at greater water depth. Changes in the ratio between the protein amino acid...... aspartate and its non-protein degradation product β-alanine confirmed this observation. Furthermore, estimates of THAA mineralization showed that sedimentary amino acid reactivity decreased with both increasing water depth as well as progressive degradation status of the organic matter that was incorporated...

  4. 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.

  5. 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.

  6. 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.

  7. 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.

  8. 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.

  9. Biodegradation of Aromatic Hydrocarbons in an Extremely Acidic Environment

    Science.gov (United States)

    Stapleton, Raymond D.; Savage, Dwayne C.; Sayler, Gary S.; Stacey, Gary

    1998-01-01

    The potential for biodegradation of aromatic hydrocarbons was evaluated in soil samples recovered along gradients of both contaminant levels and pH values existing downstream of a long-term coal pile storage basin. pH values for areas greatly impacted by runoff from the storage basin were 2.0. Even at such a reduced pH, the indigenous microbial community was metabolically active, showing the ability to oxidize more than 40% of the parent hydrocarbons, naphthalene and toluene, to carbon dioxide and water. Treatment of the soil samples with cycloheximide inhibited mineralization of the aromatic substrates. DNA hybridization analysis indicated that whole-community nucleic acids recovered from these samples did not hybridize with genes, such as nahA, nahG, nahH, todC1C2, and tomA, that encode common enzymes from neutrophilic bacteria. Since these data suggested that the degradation of aromatic compounds may involve a microbial consortium instead of individual acidophilic bacteria, experiments using microorganisms isolated from these samples were initiated. While no defined mixed cultures were able to evolve 14CO2 from labeled substrates in these mineralization experiments, an undefined mixed culture including a fungus, a yeast, and several bacteria successfully metabolized approximately 27% of supplied naphthalene after 1 week. This study shows that biodegradation of aromatic hydrocarbons can occur in environments with extremely low pH values. PMID:9797263

  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. 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.

  13. Determination and Correlation for Solubility of Aromatic Acids in Solvents

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Solubility of benzoic acid, terephthalic acid and 2,6-naphthalene dicarboxylic acid in water, acetic acid, N,N-dimethyfformamide, N,N-dimethylacetamide, dimethyl sulphoxide and N-methyl-2-ketopyrrolidine were measured by dynamic method. The solubilities were calculated by UNIFAC group contribution method, in which new groups, BCCOOH and NCCOOH, were introduced to express the activity coefficients of aromatic acids and new interaction parameters of the new groups were expressed as the function of temperature, which were determined from the experimental data. The new interaction parameters provided good calculated result. The experimental data were also correlated with Wilson and λ-h models, and results were compared with present UNIFAC model.

  14. Fluorescence Quenching Method for the Determination of Analgin and Metabolin with Some Aromatic Amino Acids as Probes%某些芳香族氨基酸作探针荧光猝灭法测定安乃近及其代谢产物

    Institute of Scientific and Technical Information of China (English)

    甘晓娟; 刘绍璞; 刘忠芳; 王亚琼; 崔志平; 胡小莉

    2012-01-01

    在pH 3.2的缓冲介质中,安乃近(ANG)及其代谢产物4-甲氨基安替比林(MAA)、4-乙酰氨基安替比林(AAA)与色氨酸(Trp)、酪氨酸(Tyr)和苯丙氨酸(Phe)等芳香族氨基酸反应并形成结合产物,引起上述氨基酸的荧光发生猝灭,最大猝灭波长分别位于352 nm(ANG-Trp体系)、304 nm(ANG-Tyr,MAA-Tyr和AAA-Tyr体系)和284 nm(ANG-Phe体系).其荧光猝灭值(ΔF)在一定范围内与ANG,MAA和AAA成正比.荧光猝灭反应具有较高灵敏度,对于ANG,MAA和AAA的检出限为13.3 ng/mL(ANG-Trp体系)、15.8 ng/mL(ANG-Tyr体系)、64.5 ng/mL(ANG-Phe体系)、150.0 ng/mL(MAA-Tyr体系)和230.8 ng/mL(AAA-Tyr体系).实验研究了荧光猝灭反应的适宜条件和影响因素,考察了共存物质的影响,表明方法具有良好的选择性,可用于ANG片剂及其代谢物尿药浓度的快速测定.从吸收光谱的变化、温度的影响以及Stern-Volmer作图,判断该反应为静态猝灭反应,氨基酸和安乃近通过静电引力和芳基堆积作用而形成1∶1的复合物.%In pH 3.2 Britton-Robinson(BR) buffer medium,analgin(ANG) and metabolin of 4-methylaminoantipyrine(MAA) and 4-acetylaminoantipyrine(AAA) can react with some aromatic amino acids such as tryptophane(Trp),tyrosine(Tyr) and phenylalanine(Phe) to form complexes,which lead to fluorescence quenching of above amino acids,and the maximum quenching wavelength is at 352 nm(ANG-Trp system),304 nm(ANG-Tyr,MAA-Tyr and AAA-Tyr system),284 nm(ANG-Phe system),re-spectively.Fluorescence quenching value(ΔF) is proportional to the concentration of ANG,MAA and AAA in a certain range.Fluorescence quenching methods for the determination of ANG,MAA and AAA have high sensitivity with the detection limits of 13.3 ng/mL(Trp-ANG system),15.8 ng/mL(Tyr-ANG system),64.5 ng/mL(Phe-ANG system),150.0 ng/mL(MAA-Tyr system) and 230.8 ng

  15. 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.

  16. 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.

  17. D-Amino acids in the brain and mutant rodents lacking D-amino-acid oxidase activity.

    Science.gov (United States)

    Yamanaka, Masahiro; Miyoshi, Yurika; Ohide, Hiroko; Hamase, Kenji; Konno, Ryuichi

    2012-11-01

    D-Amino acids are stereoisomers of L-amino acids. They are often called unnatural amino acids, but several D-amino acids have been found in mammalian brains. Among them, D-serine is abundant in the forebrain and functions as a co-agonist of NMDA receptors to enhance neurotransmission. D-Amino-acid oxidase (DAO), which degrades neutral and basic D-amino acids, is mainly present in the hindbrain. DAO catabolizes D-serine and, therefore, modulates neurotransmission. In the brains of mutant mice and rats lacking DAO activity, the amounts of D-serine and other D-amino acids are markedly increased. Mutant mice manifested behavioral changes characteristic of altered NMDA receptor activity, likely due to increased levels of D-serine. D-Serine and DAO have been demonstrated to play important roles in cerebellar development and synaptic plasticity. They have also implicated in amyotrophic lateral sclerosis and pain response. There have also been several lines of evidence correlating DAO with schizophrenia. Taken together, the experiments indicate that D-amino acids and DAO have pivotal functions in the central nervous system.

  18. Enantioseparation of Amino Acids by Micelle-Enhanced Ultrafiltration : Experimental and Theoretical Studies of Copper(II) Amino Acid Interactions

    NARCIS (Netherlands)

    Bruin, de T.J.M.

    2000-01-01

    A micelle-enhanced ultrafiltration system, which can potentially be used for large scale separations, has been used to investigate the resolution of amino acid enantiomers. For this purpose amino acid derivatives were synthesized, which in combination with copper(II) ions were used as chiral selecto

  19. 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.

  20. 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.

  1. 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.

  2. Evaluation of methods to estimate the essential amino acids requirements of fish from the muscle amino acid profile

    Directory of Open Access Journals (Sweden)

    Álvaro José de Almeida Bicudo

    2014-03-01

    Full Text Available Many methods to estimate amino acid requirement based on amino acid profile of fish have been proposed. This study evaluates the methodology proposed by Meyer & Fracalossi (2005 and by Tacon (1989 to estimate amino acids requirement of fish, which do exempt knowledge on previous nutritional requirement of reference amino acid. Data on amino acid requirement of pacu, Piaractus mesopotamicus, were used to validate de accuracy of those methods. Meyer & Fracalossi's and Tacon's methodology estimated the lysine requirement of pacu, respectively, at 13 and 23% above requirement determined using dose-response method. The values estimated by both methods lie within the range of requirements determined for other omnivorous fish species, the Meyer & Fracalossi (2005 method showing better accuracy.

  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. Theoretical study of the NLO responses of some natural and unnatural amino acids used as probe molecules.

    Science.gov (United States)

    Derrar, S N; Sekkal-Rahal, M; Derreumaux, P; Springborg, M

    2014-08-01

    The first hyperpolarizabilities β of the natural aromatic amino acids tryptophan and tyrosine have been investigated using several methods and basis sets. Some of the theoretical results obtained were compared to the only experimental hyper-Rayleigh scattering data available. The sensitivity of tryptophan to its local environment was analyzed by constructing two-dimensional potential energy plots around the dipeptide tryptophan-lysine. Static hyperpolarizabilities β(0) of the found minima were calculated by a second-order Møller-Plesset (MP2) method in combination with the 6-31+G(d) basis set. Moreover, the efficiency of tryptophan and those of a series of unnatural amino acids as endogenous probe molecules were tested by calculating the nonlinear responses of some peptides. Impressive results were obtained for the amino acid ALADAN, which shows significantly improved nonlinear performance compared to other amino acids with weak nonlinear responses.

  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. Prolonged maternal amino acid infusion in late-gestation pregnant sheep increases fetal amino acid oxidation.

    Science.gov (United States)

    Rozance, Paul J; Crispo, Michelle M; Barry, James S; O'Meara, Meghan C; Frost, Mackenzie S; Hansen, Kent C; Hay, William W; Brown, Laura D

    2009-09-01

    Protein supplementation during human pregnancy does not improve fetal growth and may increase small-for-gestational-age birth rates and mortality. To define possible mechanisms, sheep with twin pregnancies were infused with amino acids (AA group, n = 7) or saline (C group, n = 4) for 4 days during late gestation. In the AA group, fetal plasma leucine, isoleucine, valine, and lysine concentrations were increased (P < 0.05), and threonine was decreased (P < 0.05). In the AA group, fetal arterial pH (7.365 +/- 0.007 day 0 vs. 7.336 +/- 0.012 day 4, P < 0.005), hemoglobin-oxygen saturation (46.2 +/- 2.6 vs. 37.8 +/- 3.6%, P < 0.005), and total oxygen content (3.17 +/- 0.17 vs. 2.49 +/- 0.20 mmol/l, P < 0.0001) were decreased on day 4 compared with day 0. Fetal leucine disposal did not change (9.22 +/- 0.73 vs. 8.09 +/- 0.63 micromol x min(-1) x kg(-1), AA vs. C), but the rate of leucine oxidation increased 43% in the AA group (2.63 +/- 0.16 vs. 1.84 +/- 0.24 micromol x min(-1) x kg(-1), P < 0.05). Fetal oxygen utilization tended to be increased in the AA group (327 +/- 23 vs. 250 +/- 29 micromol x min(-1) x kg(-1), P = 0.06). Rates of leucine incorporation into fetal protein (5.19 +/- 0.97 vs. 5.47 +/- 0.89 micromol x min(-1) x kg(-1), AA vs. C), release from protein breakdown (4.20 +/- 0.95 vs. 4.62 +/- 0.74 micromol x min(-1) x kg(-1)), and protein accretion (1.00 +/- 0.30 vs. 0.85 +/- 0.25 micromol x min(-1) x kg(-1)) did not change. Consistent with these data, there was no change in the fetal skeletal muscle ubiquitin ligases MaFBx1 or MuRF1 or in the protein synthesis regulators 4E-BP1, eEF2, eIF2alpha, and p70(S6K). Decreased concentrations of certain essential amino acids, increased amino acid oxidation, fetal acidosis, and fetal hypoxia are possible mechanisms to explain fetal toxicity during maternal amino acid supplementation.

  7. 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.

  8. Metabolism of amino acids, dipeptides and tetrapeptides by Lactobacillus sakei.

    Science.gov (United States)

    Sinz, Quirin; Schwab, Wilfried

    2012-04-01

    The microbial degradation of proteins, peptides and amino acids generates volatiles involved in the typical flavor of dry fermented sausage. The ability of three Lactobacillus sakei strains to form aroma compounds was investigated. Whole resting cells were fermented in phosphate buffer with equimolar amounts of substrates consisting of dipeptides, tetrapeptides and free amino acids, respectively. Dipeptides disappeared quickly from the solutions whereas tetrapeptides were only partially degraded. In both approaches the concentration of free amino acids increased in the reaction mixture but did not reach the equimolar amount of the initial substrates. When free amino acids were fed to the bacteria their levels decreased only slightly. Although peptides were more rapidly degraded and/or transported into the cells, free amino acids produced higher amounts of volatiles. It is suggested, that after transport into the cell peptides are only partially hydrolyzed to their amino acids, while the rest is metabolized via alternative metabolic pathways. The three L. sakei strains differed to some extend in their ability to metabolize the substrates to volatile compounds. In a few cases this was due to the position of the amino acids within the peptides. Compared to other starter cultures used for the production of dry fermented sausages, the metabolic impact of the L. sakei strains on the formation of volatiles was very low.

  9. Amino Acid Catabolism in Alzheimer's Disease Brain: Friend or Foe?

    Science.gov (United States)

    2017-01-01

    There is a dire need to discover new targets for Alzheimer's disease (AD) drug development. Decreased neuronal glucose metabolism that occurs in AD brain could play a central role in disease progression. Little is known about the compensatory neuronal changes that occur to attempt to maintain energy homeostasis. In this review using the PubMed literature database, we summarize evidence that amino acid oxidation can temporarily compensate for the decreased glucose metabolism, but eventually altered amino acid and amino acid catabolite levels likely lead to toxicities contributing to AD progression. Because amino acids are involved in so many cellular metabolic and signaling pathways, the effects of altered amino acid metabolism in AD brain are far-reaching. Possible pathological results from changes in the levels of several important amino acids are discussed. Urea cycle function may be induced in endothelial cells of AD patient brains, possibly to remove excess ammonia produced from increased amino acid catabolism. Studying AD from a metabolic perspective provides new insights into AD pathogenesis and may lead to the discovery of dietary metabolite supplements that can partially compensate for alterations of enzymatic function to delay AD or alleviate some of the suffering caused by the disease. PMID:28261376

  10. Differential diagnosis of (inherited) amino acid metabolism or transport disorders.

    Science.gov (United States)

    Blom, W; Huijmans, J G

    1992-02-01

    Disorders of amino acid metabolism or transport are most clearly expressed in urine. Nevertheless the interpretation of abnormalities in urinary amino acid excretion remains difficult. An increase or decrease of almost every amino acid in urine can be due to various etiology. To differentiate between primary and secondary aminoacido-pathies systematic laboratory investigation is necessary. Early diagnosis of disorders of amino acid metabolism or transport is very important, because most of them can be treated, leading to the prevention of (further) clinical abnormalities. In those disorders, which cannot be treated, early diagnosis in an index-patient may prevent the birth of other siblings by means of genetic counseling and prenatal diagnosis.Primary aminoacidopathies can be due to genetically determined transport disorders and enzyme deficiencies in amino acid metabolism or degradation. Secondary aminoacidopathies are the result of abnormal or deficient nutrition, intestinal dysfunction, organ pathology or other metabolic diseases like organic acidurias.A survey of amino acid metabolism and transport abnormalities will be given, illustrated with metabolic pathways and characteristic abnormal amino acid chromatograms.

  11. Distribution of soluble amino acids in maize endosperm mutants

    Directory of Open Access Journals (Sweden)

    Toro Alejandro Alberto

    2003-01-01

    Full Text Available For human nutrition the main source of vegetable proteins are cereal and legume seeds. The content of total soluble amino acids in mature endosperm of wild-type, opaque and floury maize (Zea mays L. mutants were determined by HPLC. The total absolute concentration of soluble amino acids among the mutants varied depending on the mutant. The o11 and o13 mutants exhibited the highest average content, whereas o10, fl3 and fl1 exhibited the lowest average content. In general, the mutants exhibited similar concentrations of total soluble amino acids when compared to the wild-type lines, with the clear exception of mutants o11 and fl1, with the o11 mutant exhibiting a higher concentration of total soluble amino acids when compared to its wild-type counterpart W22 and the fl1 mutant a lower concentration when compared to its wild-type counterpart Oh43. For methionine, the mutants o2 and o11 and wild-type Oh43 exhibited the highest concentrations of this amino acid. Significant differences were not observed between mutants for other amino acids such as lysine and threonine. The high lysine concentrations obtained originally for these mutants may be due to the amino acids incorporated into storage proteins, but not those present in the soluble form.

  12. Genetics Home Reference: aromatic l-amino acid decarboxylase deficiency

    Science.gov (United States)

    ... the limbs (athetosis). They may be lacking in energy (lethargic), feed poorly, startle easily, and have sleep disturbances. People with AADC deficiency may also experience episodes called oculogyric crises that involve abnormal rotation of the eyeballs; extreme ...

  13. 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

  14. 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.

  15. A common periodic table of codons and amino acids.

    Science.gov (United States)

    Biro, J C; Benyó, B; Sansom, C; Szlávecz, A; Fördös, G; Micsik, T; Benyó, Z

    2003-06-27

    A periodic table of codons has been designed where the codons are in regular locations. The table has four fields (16 places in each) one with each of the four nucleotides (A, U, G, C) in the central codon position. Thus, AAA (lysine), UUU (phenylalanine), GGG (glycine), and CCC (proline) were placed into the corners of the fields as the main codons (and amino acids) of the fields. They were connected to each other by six axes. The resulting nucleic acid periodic table showed perfect axial symmetry for codons. The corresponding amino acid table also displaced periodicity regarding the biochemical properties (charge and hydropathy) of the 20 amino acids and the position of the stop signals. The table emphasizes the importance of the central nucleotide in the codons and predicts that purines control the charge while pyrimidines determine the polarity of the amino acids. This prediction was experimentally tested.

  16. 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

  17. PROTEINS, PEPTIDES AND AMINO ACIDS AS MARKERS OF BRONCHOPULMONARY DISEASES

    Directory of Open Access Journals (Sweden)

    V. I. Fyodorov

    2013-01-01

    Full Text Available The article is a review of current literature on a content of proteins, peptides and amino acids in human exhaled breath. The results of proteomics and metabolomics applying for selective detection of individual proteins, peptides and amino acids are described. The study of exhaled breath condensate and exhaled endogenous particles contained lung proteins are considered. The peculiarities of protein, peptide and amino acid content in exhaled breath at various respiratory diseases are described. It is shown that the detectable substances may be specific markers of individual diseases.

  18. 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.

  19. SIFT: Predicting amino acid changes that affect protein function.

    Science.gov (United States)

    Ng, Pauline C; Henikoff, Steven

    2003-07-01

    Single nucleotide polymorphism (SNP) studies and random mutagenesis projects identify amino acid substitutions in protein-coding regions. Each substitution has the potential to affect protein function. SIFT (Sorting Intolerant From Tolerant) is a program that predicts whether an amino acid substitution affects protein function so that users can prioritize substitutions for further study. We have shown that SIFT can distinguish between functionally neutral and deleterious amino acid changes in mutagenesis studies and on human polymorphisms. SIFT is available at http://blocks.fhcrc.org/sift/SIFT.html.

  20. 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.

  1. Ambient cure polyimide foams prepared from aromatic polyisocyanates, aromatic polycarboxylic compounds, furfuryl alcohol, and a strong inorganic acid

    Science.gov (United States)

    Sawko, Paul M. (Inventor); Riccitiello, Salvatore R. (Inventor); Hamermesh, Charles L. (Inventor)

    1980-01-01

    Flame and temperature resistant polyimide foams are prepared by the reaction of an aromatic dianhydride, e.g., pyromellitic dianhydride, with an aromatic polyisocyanate, e.g., polymethylene polyphenylisocyanate (PAPI) in the presence of an inorganic acid and a lower molecular weight alcohol, e.g., dilute sulfuric acid or phosphoric acid and furfuryl alcohol. The exothermic reaction between the acid and the alcohol provides the heat necessary for the other reactants to polymerize without the application of any external heat. Such mixtures, therefore, are ideally suited for in situ foam formation, especially where the application of heat is not practical or possible.

  2. Transport of amino acids and GABA analogues via the human proton-coupled amino acid transporter, hPAT1

    DEFF Research Database (Denmark)

    Larsen, Mie; Larsen, Birger Brodin; Frølund, Bente;

    2008-01-01

    The objective of this study was to investigate transepithelial amino acid transport as a function of Caco-2 cell culture time. Furthermore, the objective was to investigate apical uptake characteristics of hPAT1-mediated transport under various experimental conditions. Apical amino acid uptake......, which has been shown to function as a carboxylic acid bioisostere for substrates of the GABA receptor and transport systems....

  3. 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.

  4. 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.

  5. The shikimate pathway: review of amino acid sequence, function and three-dimensional structures of the enzymes.

    Science.gov (United States)

    Mir, Rafia; Jallu, Shais; Singh, T P

    2015-06-01

    The aromatic compounds such as aromatic amino acids, vitamin K and ubiquinone are important prerequisites for the metabolism of an organism. All organisms can synthesize these aromatic metabolites through shikimate pathway, except for mammals which are dependent on their diet for these compounds. The pathway converts phosphoenolpyruvate and erythrose 4-phosphate to chorismate through seven enzymatically catalyzed steps and chorismate serves as a precursor for the synthesis of variety of aromatic compounds. These enzymes have shown to play a vital role for the viability of microorganisms and thus are suggested to present attractive molecular targets for the design of novel antimicrobial drugs. This review focuses on the seven enzymes of the shikimate pathway, highlighting their primary sequences, functions and three-dimensional structures. The understanding of their active site amino acid maps, functions and three-dimensional structures will provide a framework on which the rational design of antimicrobial drugs would be based. Comparing the full length amino acid sequences and the X-ray crystal structures of these enzymes from bacteria, fungi and plant sources would contribute in designing a specific drug and/or in developing broad-spectrum compounds with efficacy against a variety of pathogens.

  6. Formic-acid-induced depolymerization of oxidized lignin to aromatics.

    Science.gov (United States)

    Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J; Stahl, Shannon S

    2014-11-13

    Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

  7. Formic-acid-induced depolymerization of oxidized lignin to aromatics

    Science.gov (United States)

    Rahimi, Alireza; Ulbrich, Arne; Coon, Joshua J.; Stahl, Shannon S.

    2014-11-01

    Lignin is a heterogeneous aromatic biopolymer that accounts for nearly 30% of the organic carbon on Earth and is one of the few renewable sources of aromatic chemicals. As the most recalcitrant of the three components of lignocellulosic biomass (cellulose, hemicellulose and lignin), lignin has been treated as a waste product in the pulp and paper industry, where it is burned to supply energy and recover pulping chemicals in the operation of paper mills. Extraction of higher value from lignin is increasingly recognized as being crucial to the economic viability of integrated biorefineries. Depolymerization is an important starting point for many lignin valorization strategies, because it could generate valuable aromatic chemicals and/or provide a source of low-molecular-mass feedstocks suitable for downstream processing. Commercial precedents show that certain types of lignin (lignosulphonates) may be converted into vanillin and other marketable products, but new technologies are needed to enhance the lignin value chain. The complex, irregular structure of lignin complicates chemical conversion efforts, and known depolymerization methods typically afford ill-defined products in low yields (that is, less than 10-20wt%). Here we describe a method for the depolymerization of oxidized lignin under mild conditions in aqueous formic acid that results in more than 60wt% yield of low-molecular-mass aromatics. We present the discovery of this facile C-O cleavage method, its application to aspen lignin depolymerization, and mechanistic insights into the reaction. The broader implications of these results for lignin conversion and biomass refining are also considered.

  8. Supramolecular Adducts of Cucurbit[7]uril and Amino Acids in the Gas Phase

    Science.gov (United States)

    Kovalenko, Ekaterina; Vilaseca, Marta; Díaz-Lobo, Mireia; Masliy, A. N.; Vicent, Cristian; Fedin, Vladimir P.

    2016-02-01

    The complexation of the macrocyclic cavitand cucurbit[7]uril (Q7) with a series of amino acids (AA) with different side chains (Asp, Asn, Gln, Ser, Ala, Val, and Ile) is investigated by ESI-MS techniques. The 1:1 [Q7 + AA + 2H]2+ adducts are observed as the base peak when equimolar Q7:AA solutions are electrosprayed, whereas the 1:2 [Q7 + 2AA + 2H]2+ dications are dominant when an excess of the amino acid is used. A combination of ion mobility mass spectrometry (IM-MS) and DFT calculations of the 1:1 [Q7 + AA + 2H]2+ (AA = Tyr, Val, and Ser) adducts is also reported and proven to be unsuccessful at discriminating between exclusion or inclusion-type conformations in the gas phase. Collision induced dissociation (CID) revealed that the preferred dissociation pathways of the 1:1 [Q7 + AA + 2H]2+ dications are strongly influenced by the identity of the amino acid side chain, whereas ion molecule reactions towards N-butylmethylamine displayed a common reactivity pattern comprising AA displacement. Special emphasis is given on the differences between the gas-phase behavior of the supramolecular adducts with amino acids (AA = Asp, Asn, Gln, Ser, Ala, Val, and Ile) and those featuring basic (Lys and Arg) and aromatic (Tyr and Phe) side chains.

  9. Comprehensive radiolabeling, stability, and tissue distribution studies of technetium-99m single amino acid chelates (SAAC).

    Science.gov (United States)

    Maresca, Kevin P; Hillier, Shawn M; Femia, Frank J; Zimmerman, Craig N; Levadala, Murali K; Banerjee, Sangeeta R; Hicks, Justin; Sundararajan, Chitra; Valliant, John; Zubieta, Jon; Eckelman, William C; Joyal, John L; Babich, John W

    2009-08-19

    Technetium tricarbonyl chemistry has been a subject of interest in radiopharmaceutical development over the past decade. Despite the extensive work done on developing chelates for Tc(I), a rigorous investigation of the impact of changing donor groups and labeling conditions on radiochemical yields and/or distribution has been lacking. This information is crucially important if these platforms are going to be used to develop molecular imaging probes. Previous studies on the coordination chemistry of the {M(CO)(3)}(+) core have established alkylamine, aromatic nitrogen heterocycles, and carboxylate donors as effective chelating ligands. These observations led to the design of tridentate ligands derived from the amino acid lysine. Such amino acid analogues provide a tridentate donor set for chelation to the metal and an amino acid functionality for conjugation to biomolecules. We recently developed a family of single amino acid chelates (SAAC) that serve this function and can be readily incorporated into peptides via solid-phase synthesis techniques. As part of these continuing studies, we report here on the radiolabeling with technetium-99m ((99m)Tc) and stability of a series of SAAC analogues of lysine. The complexes studied include cationic, neutral, and anionic complexes. The results of tissue distribution studies with these novel complexes in normal rats demonstrate a range of distribution in kidney, liver, and intestines.

  10. Structure of the ordered hydration of amino acids in proteins: analysis of crystal structures

    Energy Technology Data Exchange (ETDEWEB)

    Biedermannová, Lada, E-mail: lada.biedermannova@ibt.cas.cz; Schneider, Bohdan [Institute of Biotechnology CAS, Videnska 1083, 142 20 Prague (Czech Republic)

    2015-10-27

    The hydration of protein crystal structures was studied at the level of individual amino acids. The dependence of the number of water molecules and their preferred spatial localization on various parameters, such as solvent accessibility, secondary structure and side-chain conformation, was determined. Crystallography provides unique information about the arrangement of water molecules near protein surfaces. Using a nonredundant set of 2818 protein crystal structures with a resolution of better than 1.8 Å, the extent and structure of the hydration shell of all 20 standard amino-acid residues were analyzed as function of the residue conformation, secondary structure and solvent accessibility. The results show how hydration depends on the amino-acid conformation and the environment in which it occurs. After conformational clustering of individual residues, the density distribution of water molecules was compiled and the preferred hydration sites were determined as maxima in the pseudo-electron-density representation of water distributions. Many hydration sites interact with both main-chain and side-chain amino-acid atoms, and several occurrences of hydration sites with less canonical contacts, such as carbon–donor hydrogen bonds, OH–π interactions and off-plane interactions with aromatic heteroatoms, are also reported. Information about the location and relative importance of the empirically determined preferred hydration sites in proteins has applications in improving the current methods of hydration-site prediction in molecular replacement, ab initio protein structure prediction and the set-up of molecular-dynamics simulations.

  11. Ab initio Calculations of the Linear and Nonlinear Optical Properties of Amino Acids

    Energy Technology Data Exchange (ETDEWEB)

    Tokarz, D; Tuer, A; Cisek, R; Krouglov, S; Barzda, V, E-mail: virgis.barzda@utoronto.ca [Department of Chemical and Physical Sciences, Department of Chemistry, Department of Physics, and Institute for Optical Sciences, University of Toronto, 3359 Mississauga Road North, Mississauga, ON L5L 1C6 (Canada)

    2010-11-01

    A number of proteins can assemble into chiral structures that display strong nonlinear optical activity. For instance, proteins such as myosin and collagen exhibit intense second harmonic generation (SHG). A large number of experimental studies on the SHG of proteins have been conducted; however few predictive models have been proposed that reliably relate the macroscopic SHG properties to the amino acids present in the peptidic chain. In this study, the linear polarizability ({alpha}), first ({beta}) and second hyperpolarizability ({gamma}) of all twenty amino acids was investigated by time-dependent Hartree-Fock calculations under physiological conditions. Ab initio calculations were performed using the GAMESSUS computational chemistry package. We have found that the aromatic amino acids give rise to the largest mean {alpha}, {beta} and {gamma} values. With this finding, we hope to apply this method to protein structures in order to understand how second harmonic signal is generated from individual amino acids, as well as, recognize how manipulation of the secondary structure of proteins might enhance SHG and third harmonic generation (THG).

  12. Factors Influencing the Synonymous Codon and Amino Acid Usage Bias in AT-rich Pseudomonas aeruginosa Phage PhiKZ

    Institute of Scientific and Technical Information of China (English)

    K. SAU; S. SAU; S. C. MANDAL; T. C. GHOSH

    2005-01-01

    To reveal how the AT-rich genome of bacteriophage PhiKZ has been shaped in order to carry out its growth in the GC-rich host Pseudomonas aeruginosa, synonymous codon and amino acid usage bias of PhiKZ was investigated and the data were compared with that of P. aeruginosa. It was found that synonymous codon and amino acid usage of PhiKZ was distinct from that of P. aeruginosa. In contrast to P. aeruginosa, the third codon position of the synonymous codons of PhiKZ carries mostly A or T base; codon usage bias in PhiKZ is dictated mainly by mutational bias and, to a lesser extent, by translational selection. A cluster analysis of the relative synonymous codon usage values of 16 myoviruses including PhiKZ shows that PhiKZ is evolutionary much closer to Escherichia coli phage T4. Further analysis reveals that the three factors of mean molecular weight, aromaticity and cysteine content are mostly responsible for the variation of amino acid usage in PhiKZ proteins, whereas amino acid usage of P. aeruginosa proteins is mainly governed by grand average of hydropathicity, aromaticity and cysteine content. Based on these observations, we suggest that codons of the phage-like PhiKZ have evolved to preferentially incorporate the smaller amino acid residues into their proteins during translation, thereby economizing the cost of its development in GC-rich P. aeruginosa.

  13. 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.

  14. Updates on industrial production of amino acids using Corynebacterium glutamicum.

    Science.gov (United States)

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

    2016-06-01

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

  15. 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.

  16. 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.

  17. Capping β-hairpin with N-terminal d-amino acid stabilizes peptide scaffold.

    Science.gov (United States)

    Makwana, Kamlesh M; Mahalakshmi, Radhakrishnan

    2016-05-01

    Various strategies exist to stabilize de novo designed synthetic peptide β-hairpins or β-sheets structures, especially at the non-hydrogen bonding position. However, strategies to stabilize strand termini, which are affected by fraying, are highly limited. Here, by substituting N-terminal aliphatic amino acid with its mirror image counterpart, we achieve a significant increase in scaffold stabilization, resulting from the formation of a terminal aliphatic-aromatic hydrophobic CH…pi cluster. Our extensive solution NMR studies support the incorporation of an N-terminal d-aliphatic amino acid in the design of short β-hairpins, while successfully retaining the overall structural scaffold. © 2016 Wiley Periodicals, Inc. Biopolymers (Pept Sci) 106: 260-266, 2016.

  18. L-tyrosine on Ag(111): universality of the amino acid 2D zwitterionic bonding scheme?

    Energy Technology Data Exchange (ETDEWEB)

    Reichert, Joachim; Barth, Johannes V. [Physik Department E20, TU Muenchen (Germany); Department of Physics and Astronomy, University of British Columbia, Vancouver (Canada); Schiffrin, Agustin [Max-Planck-Institut fuer Quantenoptik, Garching (Germany); Auwaerter, Willi; Marschall, Matthias [Physik Department E20, TU Muenchen (Germany); Weber-Bargioni, Alexander [Department of Physics and Astronomy, University of British Columbia, Vancouver (Canada); Dell' Angela, Martina; Cvetko, Dean; Bavdek, Gregor; Cossaro, Albano; Morgante, Alberto [C.N.R.-INFM, Laboratorio Nazionale TASK, Trieste (Italy)

    2010-07-01

    We present a combined study of the adsorption and ordering of the L-tyrosine amino acid on close-packed noble-metal surfaces in ultra-high vacuum by means of low-temperature STM, XPS and NEXAFS spectroscopy. Our high resolution topographical STM data reveal noncovalent molecular dimerization within the highly ordered one-dimensional nanostructures, which recalls the geometrical pattern already seen in the L-methionine/Ag(111) system and supports a universal bonding scheme for amino acids on the Ag(111) surface. XPS measurements reveal a zwitterionic adsorption, whereas NEXAFS experiments show a tilted adsorption configuration of the phenol moiety. This enables the interdigitation between aromatic side-chains of adjacent molecules via parallel-displaced {pi}-{pi} interactions which, along with the hydrogen-bonding capability of the hydroxyl functionality, could provide an explanation for the emergence of the self-assembled supramolecular nanoribbons.

  19. Survival of gas phase amino acids and nucleobases in space radiation conditions

    Science.gov (United States)

    Pilling, S.; Andrade, D. P. P.; de Castilho, R. B.; Cavasso-Filho, R. L.; Lago, A. F.; Coutinho, L. H.; de Souza, G. G. B.; Boechat-Roberty, H. M.; de Brito, A. Naves

    2008-10-01

    We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interpla-netary radiation analogs conditions. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using a photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70 80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.

  20. Survival of gas phase amino acids and nucleobases in space radiation conditions

    CERN Document Server

    Pilling, S; de Castilho, R B; Cavasso-Filho, R L; Lago, A F; Coutinho, L H; de Souza, G G B; Boechat-Roberty, H M; de Brito, A Naves

    2008-01-01

    We present experimental studies on the photoionization and photodissociation processes (photodestruction) of gaseous amino acids and nucleobases in interstellar and interplanetary radiation conditions analogs. The measurements have been undertaken at the Brazilian Synchrotron Light Laboratory (LNLS), employing vacuum ultraviolet (VUV) and soft X-ray photons. The experimental set up basically consists of a time-of-flight mass spectrometer kept under high vacuum conditions. Mass spectra were obtained using photoelectron photoion coincidence technique. We have shown that the amino acids are effectively more destroyed (up to 70-80%) by the stellar radiation than the nucleobases, mainly in the VUV. Since polycyclic aromatic hydrocarbons have the same survival capability and seem to be ubiquitous in the ISM, it is not unreasonable to predict that nucleobases could survive in the interstellar medium and/or in comets, even as a stable cation.

  1. 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.

  2. Protein evolution via amino acid and codon elimination

    DEFF Research Database (Denmark)

    Goltermann, Lise; Larsen, Marie Sofie Yoo; Banerjee, Rajat;

    2010-01-01

    BACKGROUND: Global residue-specific amino acid mutagenesis can provide important biological insight and generate proteins with altered properties, but at the risk of protein misfolding. Further, targeted libraries are usually restricted to a handful of amino acids because there is an exponential...... correlation between the number of residues randomized and the size of the resulting ensemble. Using GFP as the model protein, we present a strategy, termed protein evolution via amino acid and codon elimination, through which simplified, native-like polypeptides encoded by a reduced genetic code were obtained...... simultaneously), while retaining varying levels of activity. Combination of these substitutions to generate a Phe-free variant of GFP abolished fluorescence. Combinatorial re-introduction of five Phe residues, based on the activities of the respective single amino acid replacements, was sufficient to restore GFP...

  3. 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.

  4. 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...

  5. 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...

  6. Synthesis and catalytic application of amino acid based dendritic macromolecules

    NARCIS (Netherlands)

    Koten, G. van; Gossage, R.A.; Jastrzebski, J.T.B.H.; Ameijde, J. van; Mulders, S.J.E.; Brouwer, Arwin J.; Liskamp, R.M.J.

    1999-01-01

    The use of amino acid based dendrimers as molecular scaffolds for the attachment of catalytically active organometallic Ni ''pincer'' complexes, via a urea functionality, is described; the dendrimer catalysts have comparable activity to their mononuclear (NCN)NiX analogues.

  7. Chemical Approaches to Studying Labile Amino Acid Phosphorylation.

    Science.gov (United States)

    Marmelstein, Alan M; Moreno, Javier; Fiedler, Dorothea

    2017-04-01

    Phosphorylation of serine, threonine, and tyrosine residues is the archetypal posttranslational modification of proteins. While phosphorylation of these residues has become standard textbook knowledge, phosphorylation of other amino acid side chains is underappreciated and minimally characterized by comparison. This disparity is rooted in the relative instability of these chemically distinct amino acid side chain moieties, namely phosphoramidates, acyl phosphates, thiophosphates, and phosphoanhydrides. In the case of the O-phosphorylated amino acids, synthetic constructs were critical to assessing their stability and developing tools for their study. As the chemical biology community has become more aware of these alternative phosphorylation sites, methodology has been developed for the synthesis of well-characterized standards and close mimics of these phosphorylated amino acids as well. In this article, we review the synthetic chemistry that is a prerequisite to progress in this field.

  8. 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.

  9. Amyloid Aggregates Arise from Amino Acid Condensations under Prebiotic Conditions.

    Science.gov (United States)

    Greenwald, Jason; Friedmann, Michael P; Riek, Roland

    2016-09-12

    Current theories on the origin of life reveal significant gaps in our understanding of the mechanisms that allowed simple chemical precursors to coalesce into the complex polymers that are needed to sustain life. The volcanic gas carbonyl sulfide (COS) is known to catalyze the condensation of amino acids under aqueous conditions, but the reported di-, tri-, and tetra-peptides are too short to support a regular tertiary structure. Here, we demonstrate that alanine and valine, two of the proteinogenic amino acids believed to have been among the most abundant on a prebiotic earth, can polymerize into peptides and subsequently assemble into ordered amyloid fibers comprising a cross-β-sheet quaternary structure following COS-activated continuous polymerization of as little as 1 mm amino acid. Furthermore, this spontaneous assembly is not limited to pure amino acids, since mixtures of glycine, alanine, aspartate, and valine yield similar structures.

  10. 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.

  11. 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.

  12. Astrobionibbler: In Situ Microfluidic Subcritical Water Extraction of Amino Acids

    Science.gov (United States)

    Noell, A. C.; Fisher, A. M.; Takano, N.; Fors-Francis, K.; Sherrit, S.; Grunthaner, F.

    2016-10-01

    A fluidic-chip based instrument for subcritical water extraction (SCWE) of amino acids and other organics from powder samples has been developed. A variety of soil analog extractions have been performed to better understand SCWE capabilities.

  13. Synthesis of pyrazole containing α-amino acids via a highly regioselective condensation/aza-Michael reaction of β-aryl α,β-unsaturated ketones

    NARCIS (Netherlands)

    Gilfillan, Lynne; Artschwager, Raik; Harkiss, Alexander H.; Liskamp, Rob M J; Sutherland, Andrew

    2015-01-01

    A synthetic approach for the preparation of a new class of highly conjugated unnatural α-amino acids bearing a 5-arylpyrazole side-chain has been developed. Horner-Wadsworth-Emmons reaction of an aspartic acid derived β-keto phosphonate ester with a range of aromatic aldehydes gave β-aryl α,β-unsatu

  14. AMINO ACID BLOOD POOL OF CHILDREN WITH ALLERGIC DISEASES

    Directory of Open Access Journals (Sweden)

    Shmulich O. V.

    2014-01-01

    Full Text Available The amino acid blood pool of children with atopic dermatitis, bronchial asthma, urticaria, angioedema was investigated. The variability of blood plasma amino acid content (tryptophan, histidine, tyrosine, cysteine, methionine was observed. The changes of histidine and tryptophan levels might be connected with the formation of biogenic amines, such as histamine, serotonine, with take part in the development of allergic reactions and inflammatory processes in organism.

  15. 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.

  16. 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....

  17. 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.

  18. Synthesis and Characterization of Fatty Acid/Amino Acid Self-Assemblies

    Directory of Open Access Journals (Sweden)

    Joanna Gajowy

    2014-10-01

    Full Text Available In this paper, we discuss the synthesis and self-assembling behavior of new copolymers derived from fatty acid/amino acid components, namely dimers of linoleic acid (DLA and tyrosine derived diphenols containing alkyl ester pendent chains, designated as “R” (DTR. Specific pendent chains were ethyl (E and hexyl (H. These poly(aliphatic/aromatic-ester-amides were further reacted with poly(ethylene glycol (PEG and poly(ethylene glycol methyl ether of different molecular masses, thus resulting in ABA type (hydrophilic-hydrophobic-hydrophilic triblock copolymers. We used Fourier transform infrared (FTIR and nuclear magnetic resonance (NMR spectroscopies to evaluate the chemical structure of the final materials. The molecular masses were estimated by gel permeation chromatography (GPC measurements. The self-organization of these new polymeric systems into micellar/nanospheric structures in aqueous environment was evaluated using ultraviolet/visible (UV-VIS spectroscopy, dynamic light scattering (DLS and transmission electron microscopy (TEM. The polymers were found to spontaneously self-assemble into nanoparticles with sizes in the range 196–239 nm and critical micelle concentration (CMC of 0.125–0.250 mg/mL. The results are quite promising and these materials are capable of self-organizing into well-defined micelles/nanospheres encapsulating bioactive molecules, e.g., vitamins or antibacterial peptides for antibacterial coatings on medical devices.

  19. Amino acid modifiers in guayule rubber compounds

    Science.gov (United States)

    Tire producers are increasingly interested in biobased materials, including rubber but also as compounding chemicals. An alternative natural rubber for tire use is produced by guayule, a woody desert shrub native to North America. Alternative compounding chemicals include naturally-occurring amino a...

  20. Release of selected amino acids from zinc carriers

    Directory of Open Access Journals (Sweden)

    Dyja Renata

    2016-06-01

    Full Text Available The paper deals with the results of an investigation of the release of selected amino acids (histidine, tryptophan, tyrosine from model suspensions prepared by co-precipitation with zinc chloride. It has been proven that the influence of the Zn(II/amino acid molar ratio on dissolution profiles of the tested amino acids and dissolution half-life (t1/2 of histidine or tryptophan is significant. The amount of amino acid in the dispersed phase (supporting dose is a determinant of the amino acid release profile. There is a minimal supporting dose (30.0 μmol of histidine or 17.4 μmol of tryptophan that provides release of similar amounts of amino acid (4.1–4.6 μmol of histidine or 8.7–9.9 μmol of tryptophan after the same time intervals. The tyrosine release profiles follow first order kinetics since the supporting dose (0.9–11.2 μmol is limited by the tyrosine low solubility in water.

  1. Computational protein design quantifies structural constraints on amino acid covariation.

    Directory of Open Access Journals (Sweden)

    Noah Ollikainen

    Full Text Available Amino acid covariation, where the identities of amino acids at different sequence positions are correlated, is a hallmark of naturally occurring proteins. This covariation can arise from multiple factors, including selective pressures for maintaining protein structure, requirements imposed by a specific function, or from phylogenetic sampling bias. Here we employed flexible backbone computational protein design to quantify the extent to which protein structure has constrained amino acid covariation for 40 diverse protein domains. We find significant similarities between the amino acid covariation in alignments of natural protein sequences and sequences optimized for their structures by computational protein design methods. These results indicate that the structural constraints imposed by protein architecture play a dominant role in shaping amino acid covariation and that computational protein design methods can capture these effects. We also find that the similarity between natural and designed covariation is sensitive to the magnitude and mechanism of backbone flexibility used in computational protein design. Our results thus highlight the necessity of including backbone flexibility to correctly model precise details of correlated amino acid changes and give insights into the pressures underlying these correlations.

  2. D-Amino Acids in the Nervous and Endocrine Systems

    Directory of Open Access Journals (Sweden)

    Yoshimitsu Kiriyama

    2016-01-01

    Full Text Available Amino acids are important components for peptides and proteins and act as signal transmitters. Only L-amino acids have been considered necessary in mammals, including humans. However, diverse D-amino acids, such as D-serine, D-aspartate, D-alanine, and D-cysteine, are found in mammals. Physiological roles of these D-amino acids not only in the nervous system but also in the endocrine system are being gradually revealed. N-Methyl-D-aspartate (NMDA receptors are associated with learning and memory. D-Serine, D-aspartate, and D-alanine can all bind to NMDA receptors. H2S generated from D-cysteine reduces disulfide bonds in receptors and potentiates their activity. Aberrant receptor activity is related to diseases of the central nervous system (CNS, such as Alzheimer’s disease, amyotrophic lateral sclerosis, and schizophrenia. Furthermore, D-amino acids are detected in parts of the endocrine system, such as the pineal gland, hypothalamus, pituitary gland, pancreas, adrenal gland, and testis. D-Aspartate is being investigated for the regulation of hormone release from various endocrine organs. Here we focused on recent findings regarding the synthesis and physiological functions of D-amino acids in the nervous and endocrine systems.

  3. Cytokinin producing bacteria stimulate amino acid deposition by wheat roots.

    Science.gov (United States)

    Kudoyarova, Guzel R; Melentiev, Alexander I; Martynenko, Elena V; Timergalina, Leila N; Arkhipova, Tatiana N; Shendel, Galina V; Kuz'mina, Ludmila Yu; Dodd, Ian C; Veselov, Stanislav Yu

    2014-10-01

    Phytohormone production is one mechanism by which rhizobacteria can stimulate plant growth, but it is not clear whether the bacteria gain from this mechanism. The hypothesis that microbial-derived cytokinin phytohormones stimulate root exudation of amino acids was tested. The rhizosphere of wheat plants was drenched with the synthetic cytokinin trans-zeatin or inoculated with Bacillus subtilis IB-22 (which produces zeatin type cytokinins) or B. subtilis IB-21 (which failed to accumulate cytokinins). Growing plants in a split root system allowed spatial separation of zeatin application or rhizobacterial inoculation to one compartment and analyses of amino acid release from roots (rhizodeposition) into the other compartment (without either microbial inoculation or treatment with exogenous hormone). Supplying B. subtilis IB-22 or zeatin to either the whole root system or half of the roots increased concentrations of amino acids in the soil solution although the magnitude of the increase was greater when whole roots were treated. There was some similarity in amino acid concentrations induced by either bacterial or zeatin treatment. Thus B. subtilis IB-22 increased amino acid rhizodeposition, likely due to its ability to produce cytokinins. Furthermore, B. subtilis strain IB-21, which failed to accumulate cytokinins in culture media, did not significantly affect amino acid concentrations in the wheat rhizosphere. The ability of rhizobacteria to produce cytokinins and thereby stimulate rhizodeposition may be important in enhancing rhizobacterial colonization of the rhizoplane.

  4. 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.

  5. 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).

  6. 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...

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

    OpenAIRE

    2009-01-01

    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...

  8. 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...

  9. 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 (P< 0·05) in rice and lowest (P< 0·05) in rye and sorghum. The concentrations of SID indispensable AA in rice were less (P< 0·05) than in dehulled oats, but greater (P< 0·05) than in the other cereal grains, and the concentrations of SID indispensable AA in Nutridense maize were greater (P< 0·05) than in yellow dent maize and sorghum, but less (P< 0·05) than in the other cereal 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.

  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. 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.

  12. 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.

  13. 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.

  14. 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.

  15. 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.

  16. Alterations in amino acid status in cats with feline dysautonomia

    Science.gov (United States)

    Symonds, Herb W.; Knottenbelt, Clare; Cave, Tom A.; MacDonald, Susan J.; Stratton, Joanna; Leon, Irene; Turner, Judith A.; Pirie, R. Scott

    2017-01-01

    Feline dysautonomia (FD) is a multiple system neuropathy of unknown aetiology. An apparently identical disease occurs in horses (equine grass sickness, EGS), dogs, rabbits, hares, sheep, alpacas and llamas. Horses with acute EGS have a marked reduction in plasma concentrations of the sulphur amino acids (SAA) cyst(e)ine and methionine, which may reflect exposure to a neurotoxic xenobiotic. The aim of this study was to determine whether FD cats have alterations in amino acid profiles similar to those of EGS horses. Amino acids were quantified in plasma/serum from 14 FD cats, 5 healthy in-contact cats which shared housing and diet with the FD cats, and 6 healthy control cats which were housed separately from FD cats and which received a different diet. The adequacy of amino acids in the cats’ diet was assessed by determining the amino acid content of tinned and dry pelleted foods collected immediately after occurrences of FD. Compared with controls, FD cats had increased concentrations of many essential amino acids, with the exception of methionine which was significantly reduced, and reductions in most non-essential amino acids. In-contact cats also had inadequate methionine status. Artefactual loss of cysteine during analysis precluded assessment of the cyst(e)ine status. Food analysis indicated that the low methionine status was unlikely to be attributable to dietary inadequacy of methionine or cystine. Multi-mycotoxin screening identified low concentrations of several mycotoxins in dry food from all 3 premises. While this indicates fungal contamination of the food, none of these mycotoxins appears to induce the specific clinico-pathologic features which characterise FD and equivalent multiple system neuropathies in other species. Instead, we hypothesise that ingestion of another, as yet unidentified, dietary neurotoxic mycotoxin or xenobiotic, may cause both the characteristic disease pathology and the plasma SAA depletion. PMID:28333983

  17. A set of amino acids found to occur more frequently in human and fly than in plant and yeast proteomes consists of non-essential amino acids

    OpenAIRE

    2007-01-01

    We investigated the hypothesis that essential amino acids are being replaced in proteins by non-essential amino acids.We compared the amino acid composition in human, worm and fly proteomes, organisms that cannot synthesize all amino acids, with the amino acids of the proteomes of plant, bakers yeast and budding yeast, which are capable of synthesizing them. The analysis covered 460,737 proteins (212,197,907 amino acids). The data suggest a bias towards the usage of non-essential ami...

  18. 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...

  19. 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...

  20. Valuable biomolecules from nine North Atlantic red macroalgae: Amino acids, fatty acids, carotenoids, minerals and metals

    DEFF Research Database (Denmark)

    Razi Parjikolaei, Behnaz; Bruhn, Annette; Eybye, Karin Loft

    2016-01-01

    , glutamic acid, and arginine, respectively. The amino acid score of the nine algae varied from 44% to 92%, the most commonly first limiting amino acid being histidine. Lutein, β-carotene, and zeaxanthin were the identified carotenoids. Contents of all macro and trace minerals, with the exception...

  1. Effects of amino acid additives during hemodialysis of children.

    Science.gov (United States)

    Abitbol, C L; Mrozinska, K; Mandel, S; McVicar, M; Wapnir, R A

    1984-01-01

    The intradialytic losses into the dialysate of free amino acids (AA) and alpha-amino nitrogen were determined during the dialysis of three children. Variations in plasma AA were determined pre- and postdialysis. The effect of these losses with the addition of an Abbott General Amino Acid Mixture to the dialysate in concentrations of 8.5, 17, and 34 mg/100 ml was studied. The major determinant of AA losses was the plasma concentration of the AA before beginning the dialysis treatment. Dialysance of individual AA varied inversely with their molecular weights. A zero flux of alpha-amino nitrogen occurred at a derived concentration of 22 mg/100 ml of the AA additive in the dialysate. Plasma concentrations of nonessential amino acids were little affected by the dialysate additive. In contrast, total essential amino acid nitrogen which fell during baseline dialyses showed significant improvement when the AA solution was added to the dialysate. This study suggests that the addition of AA to the dialysate bath may be effective in decreasing AA nitrogen losses during dialysis.

  2. Fast mass spectrometry-based enantiomeric excess determination of proteinogenic amino acids.

    Science.gov (United States)

    Fleischer, Heidi; Thurow, Kerstin

    2013-03-01

    A rapid determination of the enantiomeric excess of proteinogenic amino acids is of great importance in various fields of chemical and biologic research and industries. Owing to their different biologic effects, enantiomers are interesting research subjects in drug development for the design of new and more efficient pharmaceuticals. Usually, the enantiomeric composition of amino acids is determined by conventional analytical methods such as liquid or gas chromatography or capillary electrophoresis. These analytical techniques do not fulfill the requirements of high-throughput screening due to their relative long analysis times. The method presented allows a fast analysis of chiral amino acids without previous time consuming chromatographic separation. The analytical measurements base on parallel kinetic resolution with pseudoenantiomeric mass tagged auxiliaries and were carried out by mass spectrometry with electrospray ionization. All 19 chiral proteinogenic amino acids were tested and Pro, Ser, Trp, His, and Glu were selected as model substrates for verification measurements. The enantiomeric excesses of amino acids with non-polar and aliphatic side chains as well as Trp and Phe (aromatic side chains) were determined with maximum deviations of the expected value less than or equal to 10ee%. Ser, Cys, His, Glu, and Asp were determined with deviations lower or equal to 14ee% and the enantiomeric excess of Tyr were calculated with 17ee% deviation. The total screening process is fully automated from the sample pretreatment to the data processing. The method presented enables fast measurement times about 1.38 min per sample and is applicable in the scope of high-throughput screenings.

  3. 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.

  4. 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.

  5. Amino acid catabolism by Lactobacillus helveticus in cheese

    DEFF Research Database (Denmark)

    Kananen, Soila Kaarina

    Amino acid catabolism is the final step in the conversion of caseins to flavour compounds and a part of a complex combination of biochemical pathways in cheese flavour formation. Lactobacillus helveticus is a thermophilic lactic acid bacterium that is used in cheese manufacture as a primary starter...... culture or as an adjunct culture. It has shown high proteolytic activities in conversion of caseins to peptides and further to amino acids and flavour compounds. Better understanding of the enzyme activity properties and the influence of different properties on final cheese flavour is favourable...... for developing new cheese products with enhanced flavour. The aim of this Ph.D. study was to investigate the importance of strain variation of Lb. helveticus in relation flavour formation in cheese related to amino acid catabolism. Aspects of using Lb. helveticus as starter as well as adjunct culture in cheese...

  6. Complete amino acid sequence of the Aspergillus cytotoxin mitogillin

    Energy Technology Data Exchange (ETDEWEB)

    Fernandez-Luna, J.L.; Lopez-Otin, C.; Soriano, F.; Mendez, E.

    1985-02-12

    The complete amino acid sequence of the cytotoxin mitogillin has been determined by sequencing the intact chain and peptide fragments produced by cleavage at methionyl, arginyl, lysyl, and tryptophanyl residues and at one aspartic acid-proline bond. The protein consists of 149 amino acid residues with alanine at the NH/sub 2/ terminus and histidine at the COOH terminus. The calculated Mr of the native mitogillin was 16,867. The native molecule presents two disulfide bridges, one between cysteine residues at positions 5 and 147 and another one between cysteine residues at positions 75 and 131. The amino acid sequence of mitogillin shows 86% homology with another cytotoxic protein called alpha-sarcin.

  7. 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.

  8. How Amino Acids and Peptides Shaped the RNA World

    Directory of Open Access Journals (Sweden)

    Peter T.S. van der Gulik

    2015-01-01

    Full Text Available 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.

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

    Science.gov (United States)

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

    2014-10-15

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

  10. 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.

  11. 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.

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

    Science.gov (United States)

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

    2014-05-20

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

  13. Industrial production of amino acids by coryneform bacteria.

    Science.gov (United States)

    Hermann, Thomas

    2003-09-04

    In the 1950s Corynebacterium glutamicum was found to be a very efficient producer of L-glutamic acid. Since this time biotechnological processes with bacteria of the species Corynebacterium developed to be among the most important in terms of tonnage and economical value. L-Glutamic acid and L-lysine are bulk products nowadays. L-Valine, L-isoleucine, L-threonine, L-aspartic acid and L-alanine are among other amino acids produced by Corynebacteria. Applications range from feed to food and pharmaceutical products. The growing market for amino acids produced with Corynebacteria led to significant improvements in bioprocess and downstream technology as well as in molecular biology. During the last decade big efforts were made to increase the productivity and to decrease the production costs. This review gives an overview of the world market for amino acids produced by Corynebacteria. Significant improvements in bioprocess technology, i.e. repeated fed batch or continuous production are summarised. Bioprocess technology itself was improved furthermore by application of more sophisticated feeding and automatisation strategies. Even though several amino acids developed towards commodities in the last decade, side aspects of the production process like sterility or detection of contaminants still have increasing relevance. Finally one focus of this review is on recent developments in downstream technology.

  14. Degradation of amino acids to short-chain fatty acids in humans. An in vitro study

    DEFF Research Database (Denmark)

    Rasmussen, H S; Holtug, K; Mortensen, P B

    1988-01-01

    Short-chain fatty acids (SCFA) originate mainly in the colon through bacterial fermentation of polysaccharides. To test the hypothesis that SCFA may originate from polypeptides as well, the production of these acids from albumin and specific amino acids was examined in a faecal incubation system....... Albumin was converted to all C2-C5-fatty acids, whereas amino acids generally were converted to specific SCFA, most often through the combination of a deamination and decarboxylation of the amino acids, although more complex processes also took place. This study indicates that a part of the intestinal...

  15. 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.

  16. 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.

  17. Regulation of uterine and umbilical amino acid uptakes by maternal amino acid concentrations.

    Science.gov (United States)

    Thureen, P J; Anderson, S M; Hay, W W

    2000-09-01

    We tested the hypothesis that decreased fetal amino acid (AA) supply, produced by maternal hypoaminoacidemia (low AA) during hyperglycemia (HG), is reversible with maternal AA infusion and regulates fetal insulin concentration ([I]). We measured net uterine and umbilical AA uptakes during maternal HG/low AA concentration ([AA]) and after maternal intravenous infusion of a mixed AA solution. After 5 days HG, all maternal [AA] except glycine were decreased >50%, particularly essential [AA] (P infusion increased net uterine uptakes of Val, Leu, Ile, Met, and Ser and net umbilical uptakes of Val, Leu, Ile, Met, Phe, and Arg but did not change net uteroplacental uptake of any AA. Fetal [I] increased 55 +/- 14%, P < 0.001, with correction of fetal [AA], despite the lack of change in fetal glucose concentration. Thus generalized maternal hypoaminoacidemia decreases uterine and umbilical uptakes of primarily the essential AA and decreases fetal branched-chain [AA]. These changes are reversed with correction of maternal [AA], which also increases fetal [I].

  18. Hidden thermodynamic information in protein amino acid mutation tables

    Science.gov (United States)

    Phillips, J. C.

    2017-03-01

    We combine the standard 1992 20 × 20 substitution matrix based on block alignment, BLOSUM62, with the standard 1982 amino acid hydropathicity scale KD as well as the modern 2007 hydropathicity scale MZ, and compare the results. The 20-parameter KD and MZ hydropathicity scales have different thermodynamic character, corresponding to first- and second-order transitions. The KD and MZ comparisons show that the mutation rates reflect quantitative iteration of qualitative amino acid-phobic and -philic binary 2 × 10 properties that define quaternary 4 × 5 subgroups (but not quinary 5 × 4 subgroups), with the modern MZ bioinformatic scale giving much better results. The quaternary 5-mer MZ 4 × 5 subgroups are called mutons (Mu5). Among all hydropathicity scales, the MZ scale uniquely exhibits a smooth, deep mutational minimum at its center associated with alanine, glycine, the smallest amino acid, and histidine.

  19. 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.

  20. Thermochemical study of amino acid imprinted polymer films.

    Science.gov (United States)

    Chai, Ziyi; BelBruno, Joseph J

    2015-11-01

    Molecularly imprinted polymers provide an alternative to traditional methods of amino acid analysis. The imprinted polymers are more robust and significantly less expensive than, for example, ELISA analysis. Amino acid imprinted nylon-6 thin films were studied by differential scanning calorimetry and scanning electron microscopy. Endothermic peaks were observed for imprinted films at temperatures higher than that for pure nylon, indicating the formation of a more-ordered, hydrogen bonded polymer. Removal of the amino acid from the imprinted film resulted in reversion to the peak observed for pure nylon-6. Additives, β-cyclodextrin and multiwalled carbon nanotubes, were added to the imprinted polymer solutions as a means to increase the porosity of the films. These studies resulted in alternative morphologies and calorimetric results that provide additional functionalities and applications for imprinted polymers.

  1. 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.

  2. Supernovae and the Chirality of the Amino Acids

    CERN Document Server

    Boyd, R N; Onaka, T

    2010-01-01

    A mechanism for creating amino acid enantiomerism that always selects the same global chirality is identified, and subsequent chemical replication and galactic mixing that would populate the galaxy with the predominant species is described. This involves: (1) the spin of the 14N 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 formed from the supernova selectively destroying one orientation of the 14N, and thus selecting the chirality associated with the other 14N orientation; (3) chemical evolution, by which the molecules replicate and evolve to more complex forms of a single chirality on a relatively short timescale; and (4) galactic mixing on a longer timescale mixing the selected molecules throughout the galaxy.

  3. 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.

  4. Analysis of amino acids and carbohydrates in green coffee.

    Science.gov (United States)

    Murkovic, Michael; Derler, Karin

    2006-11-30

    The analysis of carbohydrates and amino acids in green coffee is of the utmost importance since these two classes of compounds act as precursors of the Maillard reaction during which the colour and aroma are formed. During the course of the Maillard reaction potentially harmful substances like acrylamide or 5-hydroxymethyl-furfural accrue as well. The carbohydrates were analysed by anion-exchange chromatography with pulsed amperometric detection and the amino acids by reversed phase chromatography after derivatization with 6-amino-quinolyl-N-hydroxysuccinimidyl carbamate and fluorescence detection. Both methods had to be optimized to obtain a sufficient resolution of the analytes for identification and quantification. Sucrose is the dominant carbohydrate in green coffee with a concentration of up to 90 mg/g (mean = 73 mg/g) in arabica beans and significantly lower amounts in robusta beans (mean=45 mg/g). Alanine is the amino acid with the highest concentration (mean = 1200 microg/g) followed by asparagine (mean = 680 microg/g) in robusta and 800 microg/g and 360 microg/g in arabica respectively. In general, the concentration of amino acids is higher in robusta than in arabica.

  5. 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

  6. A Soluble, Folded Protein without Charged Amino Acid Residues

    DEFF Research Database (Denmark)

    Højgaard, Casper; Kofoed, Christian; Espersen, Roall;

    2016-01-01

    Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable...... side chains can maintain solubility, stability, and function. As a model, we used a cellulose-binding domain from Cellulomonas fimi, which, among proteins of more than 100 amino acids, presently is the least charged in the Protein Data Bank, with a total of only four titratable residues. We find...

  7. Control of immune response by amino acid metabolism.

    Science.gov (United States)

    Grohmann, Ursula; Bronte, Vincenzo

    2010-07-01

    The interaction between pathogenic microorganisms and their hosts is regulated by reciprocal survival strategies, including competition for essential nutrients. Though paradoxical, mammalian hosts have learned to take advantage of amino acid catabolism for controlling pathogen invasion and, at the same time, regulating their own immune responses. In this way, ancient catabolic enzymes have acquired novel functions and evolved into new structures with highly specialized functions, which go beyond the struggle for survival. In this review, we analyze the evidence supporting a critical role for the metabolism of various amino acids in regulating different steps of both innate and adaptive immunity.

  8. 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

  9. An experimental and theoretical study of the amino acid side chain Raman bands in proteins

    Science.gov (United States)

    Sjöberg, Béatrice; Foley, Sarah; Cardey, Bruno; Enescu, Mironel

    2014-07-01

    The Raman spectra of a series of tripeptides with the basic formula GlyAAGly where the central amino acid (AA) was tryptophan, tyrosine, phenylalanine, glycine, methionine, histidine, lysine and leucine were measured in H2O. The theoretical Raman spectra obtained using density functional theory (DFT) calculations at the B3LYP/6-311+G(2df,2pd) level of theory allows a precise attribution of the vibrational bands. The experimental results show that there is a blue shift in the frequencies of several bands of the amino acid side chains in tripeptides compared to free amino acids, especially in the case of AAs containing aromatic rings. On the other hand, a very good agreement was found between the Raman bands of AA residues in tripeptides and those measured on three model proteins: bovine serum albumin, β-lactoglobulin and lysozyme. The present analysis contributes to an unambiguous interpretation of the protein Raman spectra that is useful in monitoring the biological reactions involving AA side chains alteration.

  10. Effects of dietary protein and amino acid levels on the expression of selected cationic amino acid transporters and serum amino acid concentration in growing pigs.

    Science.gov (United States)

    García-Villalobos, Héctor; Morales-Trejo, Adriana; Araiza-Piña, Benedicto A; Htoo, John K; Cervantes-Ramírez, Miguel

    2012-08-01

    The absorption of lysine is facilitated by leucine, but there is no information regarding the effect of crude protein, lysine and leucine levels on the expression of cationic amino acid transporters in pigs. Therefore, an experiment was conducted with 20 pigs (14.9 +/- 0.62 kg initial body weight) to evaluate the effect of two protein levels, and the content of lysine, threonine, methionine and leucine in low crude protein diets on the expression of b(0,+) and CAT-1 mRNA in jejunum, Longissimus dorsi and Semitendinosus muscles and serum concentration of amino acids. Treatments were as follows: (i) wheat-soybean meal diet, 20% crude protein (Control); (ii) wheat diet deficient in lysine, threonine and methionine (Basal diet); (iii) Basal diet plus 0.70% L-lysine, 0.27% L-threonine, 0.10% DL-methionine (Diet LTM); (iv) Diet LTM plus 0.80% L-leucine (Diet LTM + Leu). Despite the Basal diet, all diets were formulated to meet the requirements of lysine, threonine and methionine; Diet LTM + Leu supplied 60% excess of leucine. The addition of lysine, threonine and methionine in Diet LTM increased the expression of b(0,+) in jejunum and CAT-1 in the Semitendinosus and Longissiums muscles and decreased CAT-1 in jejunum; the serum concentration of lysine was also increased (p Pigs fed the Control diet expressed less b(0,+) in jejunum, and CAT-1 in the Semitendinosus and Longissiums muscles expressed more CAT-1 in jejunum (p dietary amino acids, affect the expression of cationic amino acid transporters in pigs fed wheat-based diets.

  11. Enzymatic synthesis of enantiopure alpha- and beta-amino acids by phenylalanine aminomutase-catalysed amination of cinnamic acid derivatives.

    Science.gov (United States)

    Wu, Bian; Szymanski, Wiktor; Wietzes, Piet; de Wildeman, Stefaan; Poelarends, Gerrit J; Feringa, Ben L; Janssen, Dick B

    2009-01-26

    The phenylalanine aminomutase (PAM) from Taxus chinensis catalyses the conversion of alpha-phenylalanine to beta-phenylalanine, an important step in the biosynthesis of the N-benzoyl phenylisoserinoyl side-chain of the anticancer drug taxol. Mechanistic studies on PAM have suggested that (E)-cinnamic acid is an intermediate in the mutase reaction and that it can be released from the enzyme's active site. Here we describe a novel synthetic strategy that is based on the finding that ring-substituted (E)-cinnamic acids can serve as a substrate in PAM-catalysed ammonia addition reactions for the biocatalytic production of several important beta-amino acids. The enzyme has a broad substrate range and a high enantioselectivity with cinnamic acid derivatives; this allows the synthesis of several non-natural aromatic alpha- and beta-amino acids in excellent enantiomeric excess (ee >99 %). The internal 5-methylene-3,5-dihydroimidazol-4-one (MIO) cofactor is essential for the PAM-catalysed amination reactions. The regioselectivity of amination reactions was influenced by the nature of the ring substituent.

  12. 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.

  13. Uptake of 3-[{sup 125}I]iodo-{alpha}-methyl-L-tyrosine into colon cancer DLD-1 cells: characterization and inhibitory effect of natural amino acids and amino acid-like drugs

    Energy Technology Data Exchange (ETDEWEB)

    Shikano, Naoto [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan)], E-mail: sikano@ipu.ac.jp; Ogura, Masato [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Okudaira, Hiroyuki [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan); Nakajima, Syuichi; Kotani, Takashi [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kobayashi, Masato [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan); Nakazawa, Shinya [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Baba, Takeshi; Yamaguchi, Naoto [Center for Medical Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kubota, Nobuo [Department of Radiological Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Iwamura, Yukio [Center for Humanities and Sciences, Ibaraki Prefectural University of Health Sciences, Ami-machi, Inashiki-gun, Ibaraki 300-0394 (Japan); Kawai, Keiichi [School of Health Sciences, Faculty of Medicine, Kanazawa University, Kanazawa 920-0942 (Japan)

    2010-02-15

    Introduction: We examined 3-[{sup 123}I]iodo-{alpha}-methyl-L-tyrosine ([{sup 123}I]IMT) uptake and inhibition by amino acids and amino acid-like drugs in the human DLD-1 colon cancer cell line, to discuss correlation between the inhibition effect and structure. Methods: Expression of relevant neutral amino acid transporters was examined by real-time PCR with DLD-1 cells. The time course of [{sup 125}I]IMT uptake, contributions of transport systems, concentration dependence and inhibition effects by amino acids and amino acid-like drugs (1 mM) on [{sup 125}I]IMT uptake were examined. Results: Expression of system L (4F2hc, LAT1 and LAT2), system A (ATA1, ATA2) and system ASC (ASCT1) was strongly detected; system L (LAT3, LAT4) and MCT8 were weakly detected; and B{sup 0}AT was not detected. [{sup 125}I]IMT uptake in DLD-1 cells involved Na{sup +}-independent system L primarily and Na{sup +}-dependent system(s). Uptake of [{sup 125}I]IMT in Na{sup +}-free buffer followed Michaelis-Menten kinetics, with a K{sub m} of 78 {mu}M and V{sub max} of 333 pmol/10{sup 6} cells per minute. Neutral D- and L-amino acids with branched or aromatic large side chains inhibited [{sup 125}I]IMT uptake. Tyrosine analogues, tryptophan analogues, L-phenylalanine and p-halogeno-L-phenylalanines, and gamma amino acids [including 3,4-dihydroxy-L-phenylalanine (L-DOPA), DL-threo-{beta}-(3,4-dihydroxyphenyl)serine (DOPS), 4-[bis(2-chloroethyl)amino]-L-phenylalanine and 1-(aminomethyl)-cyclohexaneacetic acid] strongly inhibited [{sup 125}I]IMT uptake, but L-tyrosine methyl ester and R(+)/S(-)-baclofen weakly inhibited uptake. The substrates of system ASC and A did not inhibit [{sup 125}I]IMT uptake except L-serine and D/L-cysteine. Conclusions: [{sup 125}I]IMT uptake in DLD-1 cells involves mostly LAT1 and its substrates' (including amino acid-like drugs derived from tyrosine, tryptophan and phenylalanine) affinity to transport via LAT1. Whether transport of gamma amino acid analogues is

  14. Fate of microbial nitrogen, carbon, hydrolysable amino acids, monosaccharides, and fatty acids in sediment

    OpenAIRE

    Veuger, Bart; van Oevelen, Dick; Middelburg, Jack J.

    2012-01-01

    The fate of microbial carbon, nitrogen, hydrolysable amino acids (HAAs), monosaccharides, and fatty acids in sediment was investigated experimentally. The microbial community of a tidal flat sediment was labeled with C-13-enriched glucose and N-15-enriched ammonium, and sediment was incubated for up to 371 days. Analysis of total concentrations and C-13- and N-15 content of bulk sediment, hydrolysable amino acids (including D-alanine), monosaccharides, total fatty acids (TFAs), and phospholip...

  15. 3-{[(Benzyloxycarbonyl]amino}butanoic acid

    Directory of Open Access Journals (Sweden)

    Isao Fujii

    2011-10-01

    Full Text Available In the title compound, C12H15NO4, the butyric acid group has a stretched trans conformation. The dihedral angle between the phenyl ring and the oxycarboxyamino N—(C=O—O—C plane is 56.6 (2°. In the crystal, an inversion dimer is formed by a pair of O—H...O hydrogen bonds. The dimers are further linked by N—H...O hydrogen bonds between amide groups, forming a tape along the b axis.

  16. Unique roles of acidic amino acids in phase transformation of calcium phosphates.

    Science.gov (United States)

    Chu, Xiaobin; Jiang, Wenge; Zhang, Zhisen; Yan, Yang; Pan, Haihua; Xu, Xurong; Tang, Ruikang

    2011-02-10

    Although phase transformation is suggested as a key step in biomineralization, the chemical scenario about how organic molecules mediate inorganic phase transformations is still unclear. The inhibitory effect of amino acids on hydroxyapatite (HAP, the main inorganic component of biological hard tissues such as bone and enamel) formation was concluded by the previous biomimetic modeling based upon direct solution crystallization. Here we demonstrate that acidic amino acids, Asp and Glu, could promote HAP crystallization from its precursor crystal, brushite (DCPD). However, such a promotion effect could not be observed when the nonacidic amino acids were applied in the transformation-based HAP formation. We found that the specific modification of acidic amino acid on crystal-solution interfaces played a key role in the phase transition. The distinct properties between DCPD and HAP in the solution resulted in an interfacial energy barrier to suppress the spontaneous formation of HAP phase on DCPD phase. Different from the other amino acids, the carboxylate-rich amino acids, Asp and Glu, could modify the interfacial characteristics of these two calcium phosphate crystals to make them similar to each other. The experiments confirmed that the involvement of Asp or Glu reduced the interfacial energy barrier between DCPD and HAP, leading to a trigger effect on the phase transformation. An in-depth understanding about the unique roles of acidic amino acids may contribute to understanding phase transformation controls druing biomineralization.

  17. {omicron}-iodoxybenzoic acid in water: optimized green alternative for multicomponent one-pot synthesis of 2-amino-3,5-dicarbonitrile-6-thiopyridines

    Energy Technology Data Exchange (ETDEWEB)

    Takale, Santosh; Patil, Jaidas; Pisal, Rajaram, E-mail: achaskar25@gmail.com [Changu Kana Thakur Research Centre, Mumbai (India); Padalkar, Vikas [Institute of Chemical Technology, Matunga, Mumbai (India); Chaskar, Atul [Department of Chemistry, National Taiwan University, Taipei (China)

    2012-05-15

    A multicomponent one-pot reaction of aromatic aldehyde, malononitrile and thiophenol in the presence of iodoxybenzoic acid (IBX) in aqueous media furnished 2-amino-3,5-dicarbonitrile- 6-thiopyridine in good to excellent yield. Eventually, a catalyst could be easily recovered and reused without loss of its catalytic property. (author)

  18. 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...

  19. 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....

  20. Altered amino acid excretion in children with autism.

    Science.gov (United States)

    Evans, Craig; Dunstan, R Hugh; Rothkirch, Tony; Roberts, Tim K; Reichelt, Karl L; Cosford, Robyn; Deed, Gary; Ellis, Libby B; Sparkes, Diane L

    2008-02-01

    Autism is a complex and life-long behavioural disorder of unknown aetiology. Recent reports have indicated the involvement of digestive tract dysfunction and possible complications from inadequate nutrition. In this study, 34 autistic children (12 untreated and 22 receiving therapeutic treatments related to digestive function and nutritional uptake) and 29 control subjects (all 5-15 years of age) were investigated to determine whether there were any anomalies in the urinary excretion of amino acids, glucose, sucrose, arabinose and tartaric acid using GC/FID and GC/MS analysis techniques. Significantly lower relative urinary levels of essential amino acids were revealed for both the untreated (mean +/- SEM, 32.53 +/- 3.09%) and treated (31.98 +/- 2.87%) autistic children compared with the controls (37.87 +/- 1.50%). There were no significant differences in measured excretions of sugars or tartaric acid. It was concluded that the untreated autistic children had evidence of altered metabolic homeostasis.

  1. Chiral Recognition of Amino Acids by Magnetoelectrodeposited Cu Film Electrodes

    Directory of Open Access Journals (Sweden)

    Iwao Mogi

    2011-01-01

    Full Text Available Chiral behavior of magnetoelectrodeposited (MED Cu film electrodes was investigated for the electrochemical reactions of amino acids. The Cu films were electrodeposited under a magnetic field of 5 T perpendicular to the electrode surface. Such MED Cu films were employed as an electrode, and cyclic voltammograms were measured for the electrochemical reactions of several kinds of amino acids. Chiral behavior was clearly observed as oxidation current difference between the enantiomers of alanine, aspartic acid, and glutamic acid. The MED film electrodes with the thickness of 50~500 nm exhibited such chiral behavior, and their surface morphologies had network structures, which could be induced by the micro-MHD effect.

  2. Amino acid transport by prosthecae of Asticcacaulis biprosthecum: evidence for a broad-range transport system.

    Science.gov (United States)

    Tam, E; Pate, J L

    1985-10-01

    Prosthecae purified from cells of Asticcaulis biprosthecum possess active transport systems that transport all 20 amino acids tested. Using ascorbate-reduced phenazine methosulphate in the presence of oxygen, all 20 amino acids are accumulated against a concentration gradient by isolated prosthecae. Results of experiments testing the inhibition of transport of one amino acid by another, and of experiments testing the exchange of exogenous amino acids with those preloaded in prosthecae, along with characteristics of mutants defective in amino acid transport, suggest the presence in prosthecae of three amino acid transport systems. One, the general or G system, transports at least 18 of the 20 amino acids tested. Another system, referred to as the proline or P system, transports seven amino acids (including proline) that are also transported by the G system. The third system transports only glutamate and aspartate, and is referred to as the acidic amino acid transport system or A system.

  3. Distribution of D-amino acids in vinegars and involvement of lactic acid bacteria in the production of D-amino acids.

    Science.gov (United States)

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

    2013-01-01

    Levels of free D-amino acids were compared in 11 vinegars produced from different sources or through different manufacturing processes. To analyze the D- and L-amino acids, the enantiomers were initially converted into diastereomers using pre-column derivatization with o-phthaldialdehyde plus N-acethyl-L-cysteine or N-tert-butyloxycarbonyl-L-cysteine. This was followed by separation of the resultant fluorescent isoindol derivatives on an octadecylsilyl stationary phase using ultra-performance liquid chromatography. The analyses showed that the total D-amino acid level in lactic fermented tomato vinegar was very high. Furthermore, analysis of the amino acids in tomato juice samples collected after alcoholic, lactic and acetic fermentation during the production of lactic fermented tomato vinegar showed clearly that lactic fermentation is responsible for the D-amino acids production; marked increases in D-amino acids were seen during lactic fermentation, but not during alcoholic or acetic fermentation. This suggests lactic acid bacteria have a greater ability to produce D-amino acids than yeast or acetic acid bacteria.

  4. The Synthesis and Evaluation of Arctigenin Amino Acid Ester Derivatives.

    Science.gov (United States)

    Cai, En-Bo; Yang, Li-Min; Jia, Cai-Xia; Zhang, Wei-Yuan; Zhao, Yan; Li, Wei; Song, Xing-Zhuo; Zheng, Man-Ling

    2016-10-01

    The use of arctigenin (ARG), a traditional medicine with many pharmacological activities, has been restricted due to its poor solubility in water. Five amino acid derivatives of ARG have been synthesized using glycine, o-alanine, valine, leucine, and isoleucine, which have t-butyloxy carbonyl (BOC) as a protective group. In this study, we examined the effects of removing these protective groups. The results showed that the amino acid derivatives have better solubility and nitrite-clearing ability than ARG. Among the compounds tested, the amino acid derivatives without protective group were the best. Based on these results, ARG and its two amino acid derivatives without protective group (ARG8, ARG10) were selected to evaluate their anti-tumor activity in vivo at a dosage of 40 mg/kg. The results indicated that ARG8 and ARG10 both exhibit more anti-tumor activity than ARG in H22 tumor-bearing mice. The tumor inhibition rates of ARG8 and ARG10 were 69.27 and 43.58%, which was much higher than ARG. Furthermore, the mice treated with these compounds exhibited less damage to the liver, kidney and immune organs compared with the positive group. Furthermore, ARG8 and ARG10 improved the serum cytokine levels significantly compared to ARG. In brief, this study provides a method to improve the water solubility of drugs, and we also provide a reference basis for new drug development.

  5. 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

  6. 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 a...

  7. Amino acid nutrition beyond methionine and lysine for milk protein

    Science.gov (United States)

    Amino acids are involved in many important physiological processes affecting the production, health, and reproduction of high-producing dairy cows. Most research and recommendations for lactating dairy cows has focused on methionine and lysine for increasing milk protein yield. This is because these...

  8. Integrated Micro-Chip Amino Acid Chirality Detector for MOD

    Science.gov (United States)

    Glavin, D. P.; Bada, J. L.; Botta, O.; Kminek, G.; Grunthaner, F.; Mathies, R.

    2001-01-01

    Integration of a micro-chip capillary electrophoresis analyzer with a sublimation-based extraction technique, as used in the Mars Organic Detector (MOD), for the in-situ detection of amino acids and their enantiomers on solar system bodies. Additional information is contained in the original extended abstract.

  9. Stereoselective synthesis of amino acid derivatives using carbohydrates as templates

    OpenAIRE

    Kunz, Horst; Sager, Wilfried; Pfrengle, Waldemar; Laschat, Sabine; Schanzenbach, Dirk

    1993-01-01

    Glycosylamines contain the easily cleavable semi-aminal-type N-glycosidic bond. O-Protected glycosylamines, therefore, can advantageously be used as a form of "asymmetric ammonia", for instance, in Strecker syntheses and in Ugi reactions to give amino acid amides as well as in modifications of the Mannich reaction.

  10. Syntrophic degradation of amino acids by thermophilic methanogenic consortia

    NARCIS (Netherlands)

    Plugge, C.M.

    2001-01-01

    Waste water usually contains large amounts of different organic compounds. A variety of microbial processes are involved in the anaerobic methanogenic treatment of waste water, such as hydrolysis of lipids, polysaccharides and proteins, fermentation of sugars and amino acids, acetogenic conversion o

  11. 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

  12. 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.

  13. A Soluble, Folded Protein without Charged Amino Acid Residues

    DEFF Research Database (Denmark)

    Højgaard, Casper; Kofoed, Christian; Espersen, Roall;

    2016-01-01

    Charges are considered an integral part of protein structure and function, enhancing solubility and providing specificity in molecular interactions. We wished to investigate whether charged amino acids are indeed required for protein biogenesis and whether a protein completely free of titratable ...

  14. 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.

  15. 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

  16. 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

  17. 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.

  18. 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...

  19. Branched-chain amino acids for people with hepatic encephalopathy

    DEFF Research Database (Denmark)

    Gluud, Lise Lotte; Dam, Gitte; Les, Iñigo;

    2015-01-01

    -chain amino acids (BCAA) versus control interventions has evaluated if BCAA may benefit people with hepatic encephalopathy. OBJECTIVES: To evaluate the beneficial and harmful effects of BCAA versus any control intervention for people with hepatic encephalopathy. SEARCH METHODS: We identified trials through...

  20. 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.

  1. 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

  2. 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...

  3. Child stunting is associated with low circulating essential amino acids

    Science.gov (United States)

    Stunting affects about one-quarter of children under five worldwide. The pathogenesis of stunting is poorly understood. Nutritional interventions have had only modest effects in reducing stunting. We hypothesized that insufficiency in essential amino acids may be limiting the linear growth of childr...

  4. 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.

  5. 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.

  6. Predictable conformational diversity in foldamers of sugar amino acids.

    Science.gov (United States)

    Menyhard, Dora K; Hudaky, Ilona; Jákli, Imre; Juhász, György; Perczel, András

    2017-03-27

    Systematic conformational search was carried out for monomers and homohexamers of furanoid β-amino acids: cis-(S,R) and trans-(S,S) stereoisomers of aminocyclopentane carboxylic acid (ACPC), two different aminofuranuronic-acids (AFU(α) and AFU(β)), their isopropylidene derivatives (AFU(ip)) as well as the key intermediate β-aminotetrahydrofurancarboxylic acid (ATFC). Stereochemistry of the building blocks was chosen to match with that of natural sugar amino acid (xylose and ribose) precursors. Results show that hexamers of cis furanoid β-amino acids show great variability: while hydrophobic cyclopentane (cis(ACPC)6), and hydrophilic (cisXylAFU(α/β))6 foldamers favor two different zigzagged conformation as hexamers, the backbone fold turns into a helix in case of (cisATFC)6 (10-helix) and (cisAFU(ip))6 (14-helix). Trans stereochemistry resulted in hexamers exclusively of right-handed helix conformation, (H12(P))6, regardless of their polarity. We found that the preferred oligomeric structure of cis/(S,R)AFU(α/β) is conformationally compatible with β-pleated sheets, while that of the trans/(S,S) units match with α-helices of α-proteins.

  7. Defective intestinal amino acid absorption in Ace2 null mice.

    Science.gov (United States)

    Singer, Dustin; Camargo, Simone M R; Ramadan, Tamara; Schäfer, Matthias; Mariotta, Luca; Herzog, Brigitte; Huggel, Katja; Wolfer, David; Werner, Sabine; Penninger, Josef M; Verrey, François

    2012-09-15

    Mutations in the main intestinal and kidney luminal neutral amino acid transporter B(0)AT1 (Slc6a19) lead to Hartnup disorder, a condition that is characterized by neutral aminoaciduria and in some cases pellagra-like symptoms. These latter symptoms caused by low-niacin are thought to result from defective intestinal absorption of its precursor L-tryptophan. Since Ace2 is necessary for intestinal B(0)AT1 expression, we tested the impact of intestinal B(0)AT1 absence in ace2 null mice. Their weight gain following weaning was decreased, and Na(+)-dependent uptake of B(0)AT1 substrates measured in everted intestinal rings was defective. Additionally, high-affinity Na(+)-dependent transport of L-proline, presumably via SIT1 (Slc6a20), was absent, whereas glucose uptake via SGLT1 (Slc5a1) was not affected. Measurements of small intestine luminal amino acid content following gavage showed that more L-tryptophan than other B(0)AT1 substrates reach the ileum in wild-type mice, which is in line with its known lower apparent affinity. In ace2 null mice, the absorption defect was confirmed by a severalfold increase of L-tryptophan and of other neutral amino acids reaching the ileum lumen. Furthermore, plasma and muscle levels of glycine and L-tryptophan were significantly decreased in ace2 null mice, with other neutral amino acids displaying a similar trend. A low-protein/low-niacin diet challenge led to differential changes in plasma amino acid levels in both wild-type and ace2 null mice, but only in ace2 null mice to a stop in weight gain. Despite the combination of low-niacin with a low-protein diet, plasma niacin concentrations remained normal in ace2 null mice and no pellagra symptoms, such as photosensitive skin rash or ataxia, were observed. In summary, mice lacking Ace2-dependent intestinal amino acid transport display no total niacin deficiency nor clear pellagra symptoms, even under a low-protein and low-niacin diet, despite gross amino acid homeostasis alterations.

  8. Synthesis and antiproliferative activity of aromatic and aliphatic bis[aminomethylidene(bisphosphonic)] acids.

    Science.gov (United States)

    Goldeman, Waldemar; Nasulewicz-Goldeman, Anna

    2014-08-01

    A series of aromatic and aliphatic bis[aminomethylidene(bisphosphonic)] acids was synthesized in the reaction of triethylphosphite with isonitriles followed by hydrolysis or dealkylation. The in vitro anti-proliferative effect of all synthesized tetraphosphonic acids against MCF-7 breast cancer cells, J774E macrophages and HL-60 promyelocytic leukemia cells was determined. Three aromatic derivatives (5a, 5f and 5j) showed a similar or higher anti-proliferative activity than zoledronic acid.

  9. Modulating the electronic structure of amino acids: interaction of model lewis acids with anthranilic acid

    Directory of Open Access Journals (Sweden)

    Tareq Irshaidat

    2014-01-01

    Full Text Available On the basis of theoretical B3LYP calculations, Yáñez and co-workers (J. Chem. Theory Comput. 2012, 8, 2293 illustrated that beryllium ions are capable of significantly modulating (changing the electronic structures of imidazole. In this computational organic chemistry study, the interaction of this β-amino acid and five model Lewis acids (BeF1+, Be2+, AlF2(1+, AlF2+, and Al3+ were investigated. Several aspects were addressed: natural bond orbitals, including second order perturbation analysis of intra-molecular charge delocalization and the natural population analysis atomic charges; molecular geometries; selected infrared stretching frequencies (C-N, C-O, and N-H, and selected ¹H-NMR chemical shifts. The data illustrate that this interaction can weaken the H-O bond and goes beyond strengthening the intra-molecular hydrogen bond (N...H-O to cause a spontaneous transfer of the proton to the nitrogen atom in five cases generating zwitterion structures. Many new features are observed. Most importantly, the zwitterion structures include a stabilizing hydrogen bond (N-H...O that varies in relative strength according to the Lewis acid. These findings explain the experimental observations of α-amino acids (for example: J. Am. Chem. Soc. 2001, 123, 3577 and are the first reported fundamental electronic structure characterization of β-amino acids in zwitterion form.

  10. Quantitative measurement of endogenous amino acid absorption in unanaesthetized pigs.

    Science.gov (United States)

    Rerat, A; Vaissade, P; Vaugelade, P

    1988-06-01

    The present experiment was carried out with 11 pigs (mean body weight: 53.9 +/- 1.3 kg) fitted with permanent catheters in the portal vein and carotid artery and with an electromagnetic flow probe around the portal vein. They were each subjected to 2 or 3 trials at 3 to 4-day intervals. During each trial the animals received after a previous fasting of 20 h a given amount of a protein-free diet (200 to 1200 g). The blood was collected either continuously for a quantitative determination of amino nitrogen, reducing sugars, urea and ammonia (number of meals 12, mean intake: 727 +/- 60 g) or discontinuously every 30 min between 0 and 8 h after the meal for amino acid analysis (number of meals 8; mean intake 709 +/- 105 g). A rather constant appearance (2 g/h) of amino acids in the portal blood was observed throughout the postprandial period. The intestinal absorption of each amino acid was however variable and represented between 10 and 50% of the daily requirements of the animal during the measuring period (8 h). Glutamine and to a less extent glutamic acid were exceptions as they were taken up by the gut wall from the arterial blood. There was also a marked synthesis of ornithine and citrulline by the latter. Because of the low blood level of urea, there were no apparent exchanges of urea between the blood and the intestine; in contrast, the ammonia absorption represented about 70% of that observed after ingestion of normal protein diets. Most amino acids are largely taken up by the liver and peripheral tissues, but in the case of alanine the syntheses exceed the uptake.

  11. Utilization of milk amino acids for body gain in suckling mink (Mustela vison) kits

    DEFF Research Database (Denmark)

    Tauson, Anne-Helene; Fink, Rikke; Hansen, Niels E;

    2005-01-01

    The efficiency of utilization of milk amino acids for body gain in suckling mink kits from small (n = 3), medium (n = 6) and large litters (n = 9) was investigated by using 36 mink dams and their litters for measurements during lactation weeks 1 through 4. Measurements on each dam and litter were...... performed once, hence three dams per litter size each week (n = 9). Individual milk intake of kits was determined, milk samples were collected and kits were killed for determination of amino acid composition. The most abundant amino acids in milk were glutamate, leucine and aspartate making up about 40......% of total amino acids. Branched chained amino acids made up slightly more than 20% and sulphur containing amino acids less than 5% of total milk amino acids. In kit bodies the sum of glutamate, aspartate and leucine made up about 32% of amino acids, branched chain amino acids about 16% and sulphur...

  12. Equilibrium studies of ternary systems containing some selected transition metal ions, triazoles and aromatic carboxylic acids

    Energy Technology Data Exchange (ETDEWEB)

    Khalil, Mohamed Magdy; Radalla, Abd-Elatty; Qasem, Fatma; Khaled, Rehab [Beni-Suef University, Beni-Suef (Egypt)

    2014-01-15

    Solution equilibria of the binary and ternary complex systems of the divalent transition metal ions Cu{sup 2+}, Ni{sup 2+}, Zn{sup 2+}, and Co{sup 2+} with 1,2,4-triazole (TRZ), 3-mercapto-1,2,4-triazole (TRZSH), and 3-amino-1,2,4-triazole (TRZAM) and aromatic carboxylic acids (phthalic, anthranilic, salicylic, and 5-sulfosalicylic acid) have been studied pH-metrically at (25.0±0.1) .deg. C, and a constant ionic strength I=1x10{sup -1} mol L{sup -1} NaNO{sub 3} in an aqueous medium. The potentiometric titration curves show that binary and ternary complexes of these ligands are formed in solution. The stability constants of the different binary and ternary complexes formed were calculated on the basis of computer analysis of the titration data. The relative stability of the different ternary complex species is expressed in terms of Δ log K values, log X and R. S.% parameters. The effect of temperature of the medium on both the proton-ligand equilibria for TRZAM and phthalic acid and their metal-ligand equilibria with Cu{sup 2+}, Ni{sup 2+}, and Co{sup 2+} has been studied along with the corresponding thermodynamic parameters. The complexation behavior of ternary complexes is ascertained using conductivity measurements. In addition, the formation of ternary complexes in solution has been confirmed by using UV-visible spectrophotometry.

  13. 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.

  14. Selective esterification of non-conjugated carboxylic acids in the presence of conjugated or aromatic carboxylic acids over active carbon supported methanesulfonic acid

    Institute of Scientific and Technical Information of China (English)

    FENG ZeWang; ZHAO XinQi; BI Hua

    2008-01-01

    Non-conjugated carboxylic acids are selectively esterified in good yields in the presence of conjugated or aromatic carboxylic acids by stirring over active carbon supported methanesulfonic acid in dichloromethane at room temperature.

  15. Selective esterification of non-conjugated carboxylic acids in the presence of conjugated or aromatic carboxylic acids over active carbon supported methanesulfonic acid

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Non-conjugated carboxylic acids are selectively esterified in good yields in the presence of conjugated or aromatic carboxylic acids by stirring over active carbon supported methanesulfonic acid in di-chloromethane at room temperature.

  16. The antimicrobial activities of the cinnamaldehyde adducts with amino acids.

    Science.gov (United States)

    Wei, Qing-Yi; Xiong, Jia-Jun; Jiang, Hong; Zhang, Chao; Wen Ye

    2011-11-01

    Cinnamaldehyde is a well-established natural antimicrobial compound. It is probable for cinnamaldehyde to react with amino acid forming Schiff base adduct in real food system. In this paper, 9 such kind of adducts were prepared by the direct reaction of amino acids with cinnamaldehyde at room temperature. Their antimicrobial activities against Bacillus subtilis, Escherichia coli and Saccharomyces cerevisiae were evaluated with benzoic acid as a reference. The adducts showed a dose-dependent activities against the three microbial strains. Both cinnamaldehyde and their adducts were more active against B. subtilis than on E. coli, and their antimicrobial activities were higher at lower pH. Both cinnamaldehyde and its adducts were more active than benzoic acid at the same conditions. The adduct compound A was non-toxic by primary oral acute toxicity study in mice. However, in situ effect of the adduct compound A against E. coli was a little lower than cinnamaldehyde in fish meat. This paper for the first time showed that the cinnamaldehyde adducts with amino acids had similar strong antimicrobial activities as cinnamaldehyde, which may provide alternatives to cinnamaldehyde in food to avoid the strong unacceptable odor of cinnamaldehyde.

  17. 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.

  18. Regulation of adipose branched chain amino acid catabolism enzyme expression and cross-adipose amino acid flux in human obesity

    Science.gov (United States)

    Elevated blood branched chain amino acids (BCAA) are often associated with insulin resistance and type 2 diabetes. One possibility is that under these conditions there is a reduced cellular utilization and/or lower complete oxidation of BCAAs. White adipose tissue (WAT) has become appreciated as a...

  19. 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.

  20. 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.

  1. Protein and amino acid metabolism in skeletal muscle

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Guoyao.

    1989-01-01

    Isolated chick extensor digitorum communis (EDC) muscles and, in some experiments, rat skeletal muscles were used to study a number of aspects of protein and amino acid metabolism. (1) Chick EDC muscles synthesize and release large amounts of alanine and glutamine, which indirectly obtain their amino groups from branched-chain amino acids (BCAA). (2) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) decrease (P < 0.01) alanine synthesis and BCAA transamination in EDC muscles from 24-h fasted chicks by decreasing (P < 0.01) intracellular concentrations of pyruvate due to inhibition of glycolysis. (3) Glutamine is extensively degraded in skeletal muscles from both chicks and rats, thus challenging the traditional view that glutamine oxidation is negligible in skeletal muscle. The cytosolic glutamine aminotransferases L and K in the rat and the mitochondrial phosphate-activated glutaminase in the chick play important roles in the conversion of glutamine to {alpha}-ketoglutarate for further oxidation. (4) Although methionine has been reported to be extensively transaminated in rat skeletal muscle preparations in the absence of other amino acids, transamination of methionine is absent or negligible in chick and rat skeletal muscles in the presence of physiological concentrations of amino acids. (5) Glutamine at 1.0-15 mM increases (P < 0.01) protein synthesis ({sup 3}H-phenylalanine incorporation), and at 10.0-15.0 mM decreases (P < 0.05) protein degradation ({sup 3}H-phenylalanine release from prelabelled protein in vivo) in EDC muscles from fed chicks as compared to muscles incubated in the absence of glutamine. (6) Acetoacetate or DL-{beta}-hydroxybutyrate (4 mM) has a small but significant inhibitory effect (P < 0.05) on the rate of protein synthesis, but has no effect (P > 0.05) on the rate of protein degradation in EDC muscles from fed chicks.

  2. Synthesis and Biological Activity of 3-[Phenyl(1,3-thiazol-2-yl-amino]propanoic Acids and Their Derivatives

    Directory of Open Access Journals (Sweden)

    Vytautas Mickevičius

    2013-12-01

    Full Text Available New N,N-disubstituted β-amino acids and their derivatives with thiazole, aromatic, and heterocyclic substituents were synthesized from N-phenyl-N-thiocarbamoyl-β-alanine by the Hantzsch method; derivatives with hydrazone fragments were also obtained. Some of the synthesized compounds exhibited discrete antimicrobial activity, and 3-[(4-oxo-4,5-dihydro-1,3-thiazol-2-yl(phenylamino]propanoic acid was found to promote rapeseed growth and to increase seed yield and oil content.

  3. 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....

  4. 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.

  5. 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.

  6. Glucagon and Amino Acids Are Linked in a Mutual Feedback Cycle

    DEFF Research Database (Denmark)

    Holst, Jens J; Wewer Albrechtsen, Nicolai J; Pedersen, Jens

    2017-01-01

    acid administration. In patients with receptor mutations (and in knockout mice), pancreatic swelling is due to α-cell hyperplasia with gross hypersecretion of glucagon, which according to recent groundbreaking research may result from elevated amino acid levels. Additionally, solid evidence indicates...... that ureagenesis, and thereby amino acid levels, is critically controlled by glucagon. Together, this constitutes a complete endocrine system; feedback regulation involving amino acids regulates α-cell function and secretion, while glucagon, in turn, regulates amino acid turnover....

  7. Amino acid rejection behaviour as a function of concentration.

    Science.gov (United States)

    Shirley, Jason; Mandale, Stephen; Williams, Paul M

    2011-05-11

    The solute rejection versus concentration behaviour of five different amino acids has been investigated using a Nitto Denko NTR7450 nanofiltration membrane. The experimental data for amino acid rejection was also compared against a combined steric and charge rejection model. At its isoelectric point, lysine was effectively neutral and its behaviour was well described by the model incorporating a steric function only. For phenylalanine, the combined model was found to fit the data well. In contrast there was poor agreement between the model and rejection data for glutamine, glutamic acid and glycine whose rejection values at first increased with concentration. This result implied that another governing process was in operation. Dimerisation as an explanation for the observed phenomena was also investigated. Size analysis of amino acid molecules as a function of the prevailing concentration using dynamic light scattering was limited but showed no evidence of dimerisation. This data was supported by osmotic pressure measurements which demonstrated no evidence of non-linearity in the relation between osmotic pressure and concentration.

  8. Oxidative aromatization of Hantzsch 1,4-dihydropyridines by aqueous hydrogen peroxide-acetic acid

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    A simple method for the oxidative aromatization of Hantzsch 1,4-dihydropyridines to the corresponding pyridines is achieved by using hydrogen peroxide as green oxidant and acetic acid as catalyst in aqueous solution.

  9. 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 amino 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.

  10. 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...

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

    Science.gov (United States)

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

    2016-03-15

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

  12. 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.

  13. 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.

  14. [Amino acid exchange in paeci lomycosis-complicated echinococcosis].

    Science.gov (United States)

    Streliaeva, A V; Akhmedov, Iu M; Gasparian, É R; Lazareva, N B; Samylina, I A; Chebyshev, N V; Polzikov, V V; Prokina, E S; Kurilov, D V; Zuev, S S; Shcheglova, T A; Gabchenko, A K; Sadykov, V M

    2011-01-01

    The authors have detected atypical paecilomycosis-associated myocarditis with impaired amino acid exchange and pain syndrome for the first time. At first, pain occurs in the chest and radiates into the axilla, to the left arm to the finger tips, by paralyzing the arm. In some patients, pain manifests itself in both arms with radiation to the belly, by accompanying by fainting. The skin is wet, cold; the pulse is frequent and of poor volume and difficult-to-count. Heart pain spreads into the armpit and down the arm, by making the fingers numb. Attempts to use current analgesics (movalis, sirdalud, nimesil, morphine) in combination with fungicides (diflucan, mycosist, orungal) have failed to yield positive results. The homeopathic drug Latrodectus mactans, prepared from caracurt venom, in combination with the authors' designed diet and other homeopathic agents have relieved pain syndrome and normalized amino acid exchange, which offered possibilities for successful surgical treatment for echinococcosis with later recovery.

  15. 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.

  16. 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.

  17. Amino acids conferring herbicide resistance in tobacco acetohydroxyacid synthase.

    Science.gov (United States)

    Le, Dung Tien; Choi, Jung-Do; Tran, Lam-Son Phan

    2010-01-01

    Acetohydroxyacid synthase (AHAS) (EC 4.1.3.18) is a target of commercially available herbicides such as sulfonylurea, imidazolinone, and triazolopyrimidine. In plants and microorganisms, AHAS catalyzes the first common reaction in the biosynthesis pathways leading to leucine, isoleucine and valine. Intensive studies using different approaches - including site-directed mutagenesis, molecular modeling and structural analysis - on plant AHAS-s have contributed to the understanding of the herbicide-AHAS interaction. Knowledge of the critical roles of amino acid residues of plant AHAS in conferring herbicide resistance will enable the creation of new herbicide-tolerant AHAS which could be used to develop herbicide-resistant transgenic plants. Moreover, such information will also elucidate design strategies for more efficient herbicides that could also kill weeds resistant to previously used AHAS-inhibiting herbicides. In this review, we summarize the results of intensive searches for amino acid residues and their substitutions that confer herbicide resistance in tobacco AHAS.

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

    Science.gov (United States)

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

    2017-04-01

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

  19. 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,...

  20. 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...... sites in PGK resulted in a less discriminating test, yielding a marked increase in the number of reported positives at both contact and non-contact sites....