Science.gov

Sample records for cationic amino acid

  1. Photosensitizing effect of cations on amino acids and peptides.

    PubMed

    Bogdanova, N P; Khenokh, M A

    1969-01-01

    In connection with a study of the chemical evolution of abiogenically synthesized organic compounds on primitive Earth and the physical conditions of other planets, this paper reports the experimental results obtained by the photolysis of solutions of aliphatic amino acids (glycine, alanine, valine, leucine, n. leucine) and peptides in the atmosphere of the air, N2, Ar and CO2 in the presence of the most simple photocatalyzers-cations of sulphates. The evidence shows that the photochemical conversion of NH2 acids depends on the content of the atmosphere. The decay of NH2-group is most active in air. N2 and Ar exert no significant influence on deamination, whereas in the atmosphere of CO2 the formation of ammonia in valine, for example, was only 29 per cent of its total amount during photolysis in the air. Cu2+ and Fe2+ catalyzed while Al3+ inhibited the ammonia excretion. The formation of acetaldehyde during alanine photolysis was actually independent from the atmosphere of N2 and was inhibited in Ar and CO2. Oxydative processes inducing the formation of glyoxalic acid and formaldehyde were sharply inhibited in Ar, N2 and CO2. Under the influence of ultraviolet light of the decay of NH2-acids is also accompanied by the formation of new NH2-acids. The photosensitizing effect of cations induces a rupture of -CO-NH-bonds in peptides and, provided heavy radiation doses, prevents the formation of new NH2-acids. The longer the dipeptide chain, the more significant the quantum yield of its decomposition. The photolysis of dipeptides, leading to their decay, does not necessarily induce a hydrolytic rupture of -CO-NH-bonds resulting in the formation of three amino acids. The results obtained permit approaching problems concerning the effect of the gas content of the atmosphere and various cations (photocatalyzers) on photolytic conversion of abiogenically synthesized and biogenically significant substances, amino acids for example, at the action of ultraviolet light. PMID

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

    PubMed Central

    Yang, Huaiyu; Stierhof, York-Dieter; Ludewig, Uwe

    2015-01-01

    Amino acids are major primary metabolites. Their uptake, translocation, compartmentation, and re-mobilization require a diverse set of cellular transporters. Here, the broadly expressed gene product of CATIONIC AMINO ACID TRANSPORTER 9 (CAT9) was identified as mainly localized to vesicular membranes that are involved in vacuolar trafficking, including those of the trans-Golgi network. In order to probe whether and how these compartments are involved in amino acid homeostasis, a loss-of-function cat9-1 mutant and ectopic over-expressor plants were isolated. Under restricted nitrogen supply in soil, cat9-1 showed a chlorotic phenotype, which was reversed in the over-expressors. The total soluble amino acid pools were affected in the mutants, but this was only significant under poor nitrogen supply. Upon nitrogen starvation, the soluble amino acid leaf pools were lower in the over-expressor, compared with cat9-1. Over-expression generally affected total soluble amino acid concentrations, slightly delayed development, and finally improved the survival upon severe nitrogen starvation. The results potentially identify a novel function of vesicular amino acid transport mediated by CAT9 in the cellular nitrogen-dependent amino acid homeostasis. PMID:25883600

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

    PubMed

    Yang, Huaiyu; Stierhof, York-Dieter; Ludewig, Uwe

    2015-01-01

    Amino acids are major primary metabolites. Their uptake, translocation, compartmentation, and re-mobilization require a diverse set of cellular transporters. Here, the broadly expressed gene product of CATIONIC AMINO ACID TRANSPORTER 9 (CAT9) was identified as mainly localized to vesicular membranes that are involved in vacuolar trafficking, including those of the trans-Golgi network. In order to probe whether and how these compartments are involved in amino acid homeostasis, a loss-of-function cat9-1 mutant and ectopic over-expressor plants were isolated. Under restricted nitrogen supply in soil, cat9-1 showed a chlorotic phenotype, which was reversed in the over-expressors. The total soluble amino acid pools were affected in the mutants, but this was only significant under poor nitrogen supply. Upon nitrogen starvation, the soluble amino acid leaf pools were lower in the over-expressor, compared with cat9-1. Over-expression generally affected total soluble amino acid concentrations, slightly delayed development, and finally improved the survival upon severe nitrogen starvation. The results potentially identify a novel function of vesicular amino acid transport mediated by CAT9 in the cellular nitrogen-dependent amino acid homeostasis. PMID:25883600

  4. Root uptake of cationic amino acids by Arabidopsis depends on functional expression of amino acid permease 5.

    PubMed

    Svennerstam, Henrik; Ganeteg, Ulrika; Näsholm, Torgny

    2008-01-01

    * Specific transporters mediate uptake of amino acids by plant roots. Earlier studies have indicated that the lysine histidine transporter 1 and amino acid permease 1 participate in this process, but although plant roots have been shown to absorb cationic amino acids with high affinity, neither of these transporters seems to mediate transport of L-arginine (L-Arg) or L-lysine (L-Lys). * Here, a collection of T-DNA knockout mutants were screened for alterations in Arabidopsis root uptake rates of L-Arg and it was found that only the AAP5 mutant displayed clear phenotypic divergence on high concentrations of L-Arg. A second screen using low concentrations of (15)N-labelled L-Arg in the growth media also identified AAP5 as being involved in L-Arg acquisition. * Momentaneous root uptake of basic amino acids was strongly affected in AAP5 mutant lines, but their uptake of other types of amino acids was only marginally affected. Comparisons of the root uptake characteristics of AAP5 and LHT1 mutants corroborated the hypothesis that the two transporters have distinct affinity spectra in planta. * Root uptake of all tested amino acids, except L-aspartic acid (L-Asp), was significantly affected in double AAP5*LHT1 mutants, suggesting that these two transporters account for a major proportion of roots' uptake of amino acids at low concentrations. PMID:18681934

  5. The adsorption of amino acids and cations onto goethite: a prebiotic chemistry experiment.

    PubMed

    Farias, Ana Paula S F; Carneiro, Cristine E A; de Batista Fonseca, Inês C; Zaia, Cássia T B V; Zaia, Dimas A M

    2016-06-01

    Few prebiotic chemistry experiments have assessed the adsorption of biomolecules by iron oxide-hydroxides. The present work investigated the effects of cations in artificial seawaters on the adsorption of Gly, α-Ala and β-Ala onto goethite, and vice versa. Goethite served to concentrate K and Mg cations from solution; these effects could have played important roles in peptide nucleoside formation. Goethite showed low adsorption of Gly and α-Ala. On the other hand, β-Ala (a non-protein amino acid) was highly adsorbed by goethite. Because Gly and α-Ala are the most common amino acids in living beings, and iron oxide-hydroxides are widespread on Earth, additional iron oxides should be studied. Increased ionic strength in artificial seawaters decreased the adsorption of amino acids by goethite. Because Na was highly abundant in the artificial seawater, it showed the highest effect on amino acid adsorption. β-Ala increased the adsorption of K and Ca by goethite, this effect could have been important for peptide synthesis. PMID:26984319

  6. Amino acids

    MedlinePlus

    Amino acids are organic compounds that combine to form proteins . Amino acids and proteins are the building blocks of life. When proteins are digested or broken down, amino acids are left. The human body uses amino acids ...

  7. Amino acid-based cationic lipids with α-tocopherol hydrophobic tail for efficient gene delivery.

    PubMed

    Yi, Wen-Jing; Zheng, Li-Ting; Su, Rong-Chuan; Liu, Qiang; Zhao, Zhi-Gang

    2015-11-01

    In this work, three amino acid-based cationic lipids L1-L3 bearing the same α-tocopherol moiety and biodegradable ester bond linkage, but differing in the polar head-group, were prepared and applied as non-viral gene delivery vectors. The physicochemical properties such as size, zeta-potential, stability, and cellular uptake of the lipoplexes formed from lipids L1-L3 as well as the transfection efficacy (TE) were investigated. The results showed that the chemical composition of the cationic head-group clearly affects the physicochemical parameters of the amino acid-based lipids, especially the TE. Besides their low cytotoxicity, these lipoplexes also showed comparable TE to commercially available lipofectamine 2000. In particular, dipeptide lipid L3 gave excellent TE, which was 1.8 times higher than bPEI 25k in the presence of 10% serum in Hela cells. These results demonstrate the promising use of novel dipeptide lipids for safe and efficient gene delivery. PMID:25973654

  8. Effects of endotoxin exposure on cationic amino acid transporter function in ovine peripheral blood mononuclear cells.

    PubMed

    Clark, Megan F; Reade, Michael C; Boyd, C A R; Young, J Duncan

    2003-03-01

    Rodent models of sepsis differ from clinical human disease in that humans make substantially less whole-body nitric oxide and have different cellular responses to endotoxin. Sheep, when exposed to endotoxin, behave in a manner more similar to humans. Many studies of rodent peripheral blood mononuclear cells (PBMCs) exposed to endotoxin demonstrate increased cationic amino acid transporter function (particularly through the y+ transporter) to supply arginine substrate to upregulated nitric oxide synthase. Whether this is true in sheep is not known. We have studied cationic amino acid transport in sheep PBMCs stimulated with endotoxin, using labelled lysine. PBMCs stimulated both in vitro and in vivo show an initial reduction in total and y+ lysine transport (after 1-2 h exposure to endotoxin): a previously undescribed effect of endotoxin. In in vitro activated cells, the reduction in y+ transport was prevented by the lipoxygenase inhibitor, nordihydroguaretic acid (NDGA), and the phospholipase inhibitor 4-bromophenacyl bromide (4-BPAB), but not cyclohexamide or a number of other inhibitors of intracellular second-messenger pathways. In contrast after 14 h incubation, the expected increase in total and y+ lysine transport was seen. The increase in y+ transport could be prevented by cyclohexamide, dexamethasone, ibuprofen, the protein kinase C inhibitor sphingosine, NDGA and 4-BPAB. These results suggest that in response to endotoxin exposure there is an initial decrease in y+ activity mediated by a lipoxygenase product, followed by a substantial increase in y+ activity mediated by the products of either cyclo-oxygenase or lipoxygenase. Cyclo-oxygenase and/or lipoxygenase inhibition might be useful in reducing arginine transport, and hence nitric oxide production, in these cells. PMID:12621525

  9. Hyponatremic Chloride-depletion Metabolic Alkalosis Successfully Treated with High Cation-gap Amino Acid.

    PubMed

    Ryuge, Akihiro; Matsui, Katsuomi; Shibagaki, Yugo

    2016-01-01

    Chloride (Cl)-depletion alkalosis (CDA) develops due to the loss of Cl-rich body fluid, i.e., vomiting or diuretics use, and is typically treated with a chloride-rich solution such as normal saline (NS). Although NS is one of the most utilized Cl-rich solutions, high cation-gap amino acid (HCG-AA) predominantly comprises Cl and less sodium, making HCG-AA more efficient in correcting CDA. We herein report a case of CDA with chronic hyponatremia after frequent vomiting, which was successfully treated with HCG-AA without overcorrecting hyponatremia or causing hypervolemia. HCG-AA may be more beneficial than NS for treating hyponatremic or hypervolemic metabolic alkalosis. PMID:27374680

  10. Amino acid analysis

    NASA Technical Reports Server (NTRS)

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

    1974-01-01

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

  11. Amino acids

    MedlinePlus

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

  12. Real-time functional characterization of cationic amino acid transporters using a new FRET sensor.

    PubMed

    Vanoaica, Liviu; Behera, Alok; Camargo, Simone M R; Forster, Ian C; Verrey, François

    2016-04-01

    L-arginine is a semi-essential amino acid that serves as precursor for the production of urea, nitric oxide (NO), polyamines, and other biologically important metabolites. Hence, a fast and reliable assessment of its intracellular concentration changes is highly desirable. Here, we report on a genetically encoded Förster resonance energy transfer (FRET)-based arginine nanosensor that employs the arginine repressor/activator ahrC gene from Bacillus subtilis. This new nanosensor was expressed in HEK293T cells, and experiments with cell lysate showed that it binds L-arginine with high specificity and with a K d of ∼177 μM. Live imaging experiments showed that the nanosensor was expressed throughout the cytoplasm and displayed a half maximal FRET increase at an extracellular L-arginine concentration of ∼22 μM. By expressing the nanosensor together with SLC7A1, SLC7A2B, or SLC7A3 cationic amino acid transporters (CAT1-3), it was shown that L-arginine was imported at a similar rate via SLC7A1 and SLC7A2B and slower via SLC7A3. In contrast, upon withdrawal of extracellular L-arginine, intracellular levels decreased as fast in SLC7A3-expressing cells compared with SLC7A1, but the efflux was slower via SLC7A2B. SLC7A4 (CAT4) could not be convincingly shown to transport L-arginine. We also demonstrated the impact of membrane potential on L-arginine transport and showed that physiological concentrations of symmetrical and asymmetrical dimethylarginine do not significantly interfere with L-arginine transport through SLC7A1. Our results demonstrate that the FRET nanosensor can be used to assess L-arginine transport through plasma membrane in real time. PMID:26555760

  13. Expression Profile of Cationic Amino Acid Transporters in Rats with Endotoxin-Induced Uveitis

    PubMed Central

    Chang, Shu-Wen; Lee, Yi-An; Kao, Tzu-Yun

    2016-01-01

    Purpose. The transcellular arginine transportation via cationic amino acid transporter (CAT) is the rate-limiting step in nitric oxide (NO) synthesis, which is crucial in intraocular inflammation. In this study, CAT isoforms and inducible nitric oxide synthase (iNOS) expression was investigated in endotoxin-induced uveitis (EIU). Methods. EIU was induced in Lewis rats by lipopolysaccharide (LPS) injection. In the treatment group, the rats were injected intraperitoneally with the proteasome inhibitor bortezomib before EIU induction. After 24 hours, leukocyte quantification, NO measurement of the aqueous humor, and histopathological examination were evaluated. The expression of CAT isoforms and iNOS was determined by reverse transcription-polymerase chain reaction, western blotting, and immunofluorescence staining. Nuclear factor-kappa B (NF-κB) binding activity was evaluated by electrophoretic mobility shift assay. The mouse macrophage cell line RAW 264.7 was used to validate the in vivo findings. Results. LPS significantly stimulated iNOS, CAT-2A, and CAT-2B mRNA and protein expression but did not affect CAT-1 in EIU rats and RAW 264.7 cells. Bortezomib attenuated inflammation and inhibited iNOS, CAT-2A, and CAT-2B expression through NF-κB inhibition. Conclusions. CAT-2 and iNOS, but not CAT-1, are specifically involved in EIU. NF-κB is essential in the induction of CAT-2 and iNOS in EIU. PMID:27413255

  14. Cationic Amino Acid Transporter-2 Regulates Immunity by Modulating Arginase Activity

    PubMed Central

    Thompson, Robert W.; Pesce, John T.; Ramalingam, Thirumalai; Wilson, Mark S.; White, Sandy; Cheever, Allen W.; Ricklefs, Stacy M.; Porcella, Stephen F.; Li, Lili; Ellies, Lesley G.; Wynn, Thomas A.

    2008-01-01

    Cationic amino acid transporters (CAT) are important regulators of NOS2 and ARG1 activity because they regulate L-arginine availability. However, their role in the development of Th1/Th2 effector functions following infection has not been investigated. Here we dissect the function of CAT2 by studying two infectious disease models characterized by the development of polarized Th1 or Th2-type responses. We show that CAT2−/− mice are significantly more susceptible to the Th1-inducing pathogen Toxoplasma gondii. Although T. gondii infected CAT2−/− mice developed stronger IFN-γ responses, nitric oxide (NO) production was significantly impaired, which contributed to their enhanced susceptibility. In contrast, CAT2−/− mice infected with the Th2-inducing pathogen Schistosoma mansoni displayed no change in susceptibility to infection, although they succumbed to schistosomiasis at an accelerated rate. Granuloma formation and fibrosis, pathological features regulated by Th2 cytokines, were also exacerbated even though their Th2 response was reduced. Finally, while IL-13 blockade was highly efficacious in wild-type mice, the development of fibrosis in CAT2−/− mice was largely IL-13-independent. Instead, the exacerbated pathology was associated with increased arginase activity in fibroblasts and alternatively activated macrophages, both in vitro and in vivo. Thus, by controlling NOS2 and arginase activity, CAT2 functions as a potent regulator of immunity. PMID:18369473

  15. Spontaneous formation of biocompatible vesicles in aqueous mixtures of amino acid-based cationic surfactants and SDS/SDBS.

    PubMed

    Shome, Anshupriya; Kar, Tanmoy; Das, Prasanta K

    2011-02-01

    The spontaneous formation of vesicles by six amino acid-based cationic surfactants and two anionic surfactants (sodium dodecylbenzene sulfonate (SDBS) and sodium dodecyl sulfate (SDS)) is reported. The head-group structure of the cationic surfactants is minutely altered to understand their effect on vesicle formation. To establish the regulatory role of the aromatic group in self-aggregation, both aliphatic and aromatic side-chain-substituted amino acid-based cationic surfactants are used. The presence of aromaticity in any one of the constituents favors the formation of vesicles by cationic/anionic surfactant mixtures. The formation of vesicles is primarily dependent on the balance between the hydrophobicity and hydrophilicity of both cationic and anionic surfactants. Vesicle formation is characterized by surface tension, fluorescence anisotropy, transmission electron microscopy, dynamic light scattering, and phase diagrams. These vesicles are thermally stable up to 65 °C, determined by temperature-dependent fluorescence anisotropy. According to the MTT assay, these catanionic vesicles are nontoxic to NIH3T3 cells, thus indicating their wider applicability as delivery vehicles to cells. Among the six cationic surfactants examined, tryptophan- and tyrosine-based surfactants have the ability to reduce HAuCl(4) to gold nanoparticles (GNPs), which is utilized to obtain in-situ-synthesized GNPs entrapped in vesicles without the need for any external reducing agent. PMID:21275029

  16. Metabolic and secretory responses of parotid cells to cationic amino acids. Oxidation of the amino acids and interference with the oxidation of D-glucose or endogenous nutrients.

    PubMed

    Sener, A; Mourtada, A; Blachier, F; Malaisse, W J

    1990-09-01

    Cationic amino acids were recently found to stimulate amylase release from rat parotid cells. The possible relevance of their oxidative catabolism to such a secretory stimulation was investigated. D-Glucose, which was efficiently metabolized in parotid cells and which augmented O2 uptake above basal value, failed to affect basal or stimulated amylase release. L-Arginine, L-lysine and L-histidine failed to stimulate the oxidation of either exogenous D-[6-14C]glucose or endogenous nutrients in cells pre-labelled with [U-14C]palmitate or L-[U-14C]glutamine. The oxidation of L-[U-14C]arginine, L-[U-14C]ornithine, L-[U-14C]lysine and L-[U-14C]histidine, all tested at a 10 mM concentration, was much lower than that of D-[U-14C]glucose (5.6 mM). These findings argue against the view that the stimulation of amylase release by cationic amino acids would be related to their role as a source of energy in the parotid cells. PMID:1703792

  17. Dysfunction in macrophage toll-like receptor signaling caused by an inborn error of cationic amino acid transport.

    PubMed

    Kurko, Johanna; Vähä-Mäkilä, Mari; Tringham, Maaria; Tanner, Laura; Paavanen-Huhtala, Sari; Saarinen, Maiju; Näntö-Salonen, Kirsti; Simell, Olli; Niinikoski, Harri; Mykkänen, Juha

    2015-10-01

    Amino acids, especially arginine, are vital for the well-being and activity of immune cells, and disruption of amino acid balance may weaken immunity and predispose to infectious and autoimmune diseases. We present here a model of an inborn aminoaciduria, lysinuric protein intolerance (LPI), in which a single mutation in y(+)LAT1 cationic amino acid transporter gene SLC7A7 leads to a multisystem disease characterized by immunological complications, life-threatening pulmonary alveolar proteinosis and nephropathy. Macrophages are suggested to play a central role in LPI in the development of these severe secondary symptoms. We thus studied the effect of the Finnish y(+)LAT1 mutation on monocyte-derived macrophages where toll-like receptors (TLRs) act as the key molecules in innate immune response against external pathogens. The function of LPI patient and control macrophage TLR signaling was examined by stimulating the TLR2/1, TLR4 and TLR9 pathways with their associated pathogen-associated molecular patterns. Downregulation in expression of TLR9, IRF7, IRF3 and IFNB1 and in secretion of IFN-α was detected, suggesting an impaired response to TLR9 stimulation. In addition, secretion of TNF-α, IL-12 and IL-1RA by TLR2/1 stimulation and IL-12 and IL-1RA by TLR4 stimulation was increased in the LPI patients. LPI macrophages secreted significantly less nitric oxide than control macrophages, whereas plasma concentrations of inflammatory chemokines CXCL8, CXCL9 and CXCL10 were elevated in the LPI patients. In conclusion, our results strengthen the relevance of macrophages in the pathogenesis of LPI and, furthermore, suggest that cationic amino acid transport plays an important role in the regulation of innate immune responses. PMID:26210182

  18. Competition between pi and non-pi cation-binding sites in aromatic amino acids: a theoretical study of alkali metal cation (Li+, Na+, K+)-phenylalanine complexes.

    PubMed

    Siu, Fung Ming; Ma, Ngai Ling; Tsang, Chun Wai

    2004-04-19

    To understand the cation-pi interaction in aromatic amino acids and peptides, the binding of M(+) (where M(+) = Li(+), Na(+), and K(+)) to phenylalanine (Phe) is studied at the best level of density functional theory reported so far. The different modes of M(+) binding show the same order of binding affinity (Li(+)>Na(+)>K(+)), in the approximate ratio of 2.2:1.5:1.0. The most stable binding mode is one in which the M(+) is stabilized by a tridentate interaction between the cation and the carbonyl oxygen (O[double bond]C), amino nitrogen (--NH(2)), and aromatic pi ring; the absolute Li(+), Na(+), and K(+) affinities are estimated theoretically to be 275, 201, and 141 kJ mol(-1), respectively. Factors affecting the relative stabilities of various M(+)-Phe binding modes and conformers have been identified, with ion-dipole interaction playing an important role. We found that the trend of pi and non-pi cation bonding distances (Na(+)-pi>Na(+)-N>Na(+)-O and K(+)-pi>K(+)-N>K(+)-O) in our theoretical Na(+)/K(+)-Phe structures are in agreement with the reported X-ray crystal structures of model synthetic receptors (sodium and potassium bound lariat ether complexes), even though the average alkali metal cation-pi distance found in the crystal structures is longer. This difference between the solid and the gas-phase structures can be reconciled by taking the higher coordination number of the cations in the lariat ether complexes into account. PMID:15079836

  19. First-principles data set of 45,892 isolated and cation-coordinated conformers of 20 proteinogenic amino acids.

    PubMed

    Ropo, Matti; Schneider, Markus; Baldauf, Carsten; Blum, Volker

    2016-01-01

    We present a structural data set of the 20 proteinogenic amino acids and their amino-methylated and acetylated (capped) dipeptides. Different protonation states of the backbone (uncharged and zwitterionic) were considered for the amino acids as well as varied side chain protonation states. Furthermore, we studied amino acids and dipeptides in complex with divalent cations (Ca(2+), Ba(2+), Sr(2+), Cd(2+), Pb(2+), and Hg(2+)). The database covers the conformational hierarchies of 280 systems in a wide relative energy range of up to 4 eV (390 kJ/mol), summing up to a total of 45,892 stationary points on the respective potential-energy surfaces. All systems were calculated on equal first-principles footing, applying density-functional theory in the generalized gradient approximation corrected for long-range van der Waals interactions. We show good agreement to available experimental data for gas-phase ion affinities. Our curated data can be utilized, for example, for a wide comparison across chemical space of the building blocks of life, for the parametrization of protein force fields, and for the calculation of reference spectra for biophysical applications. PMID:26881946

  20. First-principles data set of 45,892 isolated and cation-coordinated conformers of 20 proteinogenic amino acids

    PubMed Central

    Ropo, Matti; Schneider, Markus; Baldauf, Carsten; Blum, Volker

    2016-01-01

    We present a structural data set of the 20 proteinogenic amino acids and their amino-methylated and acetylated (capped) dipeptides. Different protonation states of the backbone (uncharged and zwitterionic) were considered for the amino acids as well as varied side chain protonation states. Furthermore, we studied amino acids and dipeptides in complex with divalent cations (Ca2+, Ba2+, Sr2+, Cd2+, Pb2+, and Hg2+). The database covers the conformational hierarchies of 280 systems in a wide relative energy range of up to 4 eV (390 kJ/mol), summing up to a total of 45,892 stationary points on the respective potential-energy surfaces. All systems were calculated on equal first-principles footing, applying density-functional theory in the generalized gradient approximation corrected for long-range van der Waals interactions. We show good agreement to available experimental data for gas-phase ion affinities. Our curated data can be utilized, for example, for a wide comparison across chemical space of the building blocks of life, for the parametrization of protein force fields, and for the calculation of reference spectra for biophysical applications. PMID:26881946

  1. Cationic Amino Acid Uptake Constitutes a Metabolic Regulation Mechanism and Occurs in the Flagellar Pocket of Trypanosoma cruzi

    PubMed Central

    Bouvier, León A.; Cámara, María de los Milagros; Montserrat, Javier; Pereira, Claudio A.

    2012-01-01

    Trypanosomatids' amino acid permeases are key proteins in parasite metabolism since they participate in the adaptation of parasites to different environments. Here, we report that TcAAP3, a member of a Trypanosoma cruzi multigene family of permeases, is a bona fide arginine transporter. Most higher eukaryotic cells incorporate cationic amino acids through a single transporter. In contrast, T. cruzi can recognize and transport cationic amino acids by mono-specific permeases since a 100-fold molar excess of lysine could not affect the arginine transport in parasites that over-express the arginine permease (TcAAP3 epimastigotes). In order to test if the permease activity regulates downstream processes of the arginine metabolism, the expression of the single T. cruzi enzyme that uses arginine as substrate, arginine kinase, was evaluated in TcAAP3 epimastigotes. In this parasite model, intracellular arginine concentration increases 4-folds and ATP level remains constant until cultures reach the stationary phase of growth, with decreases of about 6-folds in respect to the controls. Interestingly, Western Blot analysis demonstrated that arginine kinase is significantly down-regulated during the stationary phase of growth in TcAAP3 epimastigotes. This decrease could represent a compensatory mechanism for the increase in ATP consumption as a consequence of the displacement of the reaction equilibrium of arginine kinase, when the intracellular arginine concentration augments and the glucose from the medium is exhausted. Using immunofluorescence techniques we also determined that TcAAP3 and the specific lysine transporter TcAAP7 co-localize in a specialized region of the plasma membrane named flagellar pocket, staining a single locus close to the flagellar pocket collar. Taken together these data suggest that arginine transport is closely related to arginine metabolism and cell energy balance. The clinical relevance of studying trypanosomatids' permeases relies on the

  2. Supplemental leucine and isoleucine affect expression of cationic amino acid transporters and myosin, serum concentration of amino acids, and growth performance of pigs.

    PubMed

    Cervantes-Ramírez, M; Mendez-Trujillo, V; Araiza-Piña, B A; Barrera-Silva, M A; González-Mendoza, D; Morales-Trejo, A

    2013-01-01

    Leucine (Leu) participates in the activity of cationic amino acid (aa) transporters. Also, branched-chain aa [Leu, isoleucine (Ile), and valine (Val)] share intestinal transporters for absorption. We conducted an experiment with 16 young pigs (body weight of about 16 kg) to determine whether Leu and Ile affect expression of aa transporters b(0,+) and CAT-1 in the jejunum and expression of myosin in muscle, as well as serum concentration of essential aa, and growth performance in pigs. Dietary treatments were: wheat-based diets fortified with Lys, Thr, and Met; basal diet plus 0.50% Leu; basal diet plus 0.50% Ile, and basal diet plus 0.50% Leu and 0.50% Ile. After 28 days, the pigs were sacrificed to collect blood, jejunum, and semitendinosus and longissimus muscle samples. The effects of single and combined addition of Leu and Ile were analyzed. Leu alone or combined with Ile significantly decreased daily weight gain and reduced feed conversion. Leu and Ile, alone or in combination, significantly decreased expression of b(0,+) and significantly increased CAT-1. Ile alone or combined with Leu significantly decreased myosin expression in semitendinosus and significantly decreased it in longissimus muscle. Leu alone significantly decreased Lys, Ile and Thr serum concentrations; Ile significantly decreased Thr serum concentration; combined Leu and Ile significantly decreased Thr and significantly increased Val serum concentration. We conclude that dietary levels of Leu and Ile affect growth performance, expression of aa transporters and myosin, and aa serum concentrations in pigs. PMID:23408397

  3. Expression of cationic amino acid transporters, carcass traits, and performance of growing pigs fed low-protein amino acid-supplemented versus high protein diets.

    PubMed

    Morales, A; Grageola, F; García, H; Araiza, A; Zijlstra, R T; Cervantes, M

    2013-01-01

    Free amino acids (AA) appear to be absorbed faster than protein-bound AA (PB-AA). We conducted an experiment to assess the effect of feeding pigs with a partially free (F-AA) or totally PB-AA diet on expression of selected genes and performance of pigs. The expression of cationic AA transporters b(0,+) and CAT-1 in intestinal mucosa, liver, and longissimus (LM) and semitendinosus (SM) muscles, as well as that of myosin in LM and SM, was analyzed. Twelve pigs (31.7 ± 2.7 kg) were used. The F-AA diet was based on wheat, supplemented with 0.59% L-Lys, 0.33% L-Thr, and 0.10% DL-Met. The PB-AA diet was formulated with wheat-soybean meal. Average daily feed intake was 1.53 kg per pig. The expression of b(0,+) and CAT-1 was analyzed in jejunal and ileal mucosa, liver, LM, and SM; myosin expression was also analyzed in both muscles. Pigs fed the PB-AA diet tended to have higher weight gain and feed efficiency (P < 0.10), and had thinner back fat (P = 0.02). The expression of b(0,+) was higher (P < 0.01) in jejunum but lower (P < 0.01) in the liver of pigs fed the F-AA diet; CAT-1 tended to be lower in liver but higher in LM of PB-AA pigs. Myosin expression was not affected. Intestinal AA absorption was faster in pigs fed the F-AA diet, but AA uptake by the liver seemed to be faster in pigs fed the PB-AA. Performance and expression of AA transporters and myosin suggest that the dietary content of free or protein-bound AA does not affect their availability for protein synthesis in pigs. PMID:24222247

  4. Cationic permethylated 6-monoamino-6-monodeoxy-β-cyclodextrin as chiral selector of dansylated amino acids in capillary electrophoresis.

    PubMed

    Németh, Krisztina; Domonkos, Celesztina; Sarnyai, Virág; Szemán, Julianna; Jicsinszky, László; Szente, Lajos; Visy, Júlia

    2014-10-01

    The resolution power of permethylated 6-monoamino-6-monodeoxy-βCD (PMMABCD) - a single isomer, cationic CD derivative - developed previously for chiral analyses in capillary electrophoresis was further studied here. Dansylated amino acids (Dns-AA) were chosen as amphoteric chiral model compounds. Changes in the resolutions of Dns-AAs by varying pH and selector concentrations were investigated and correlated with their structures and chemical properties (isoelectric point and lipophilicity). Maximal resolutions could be achieved at pH 6 or pH 4. The separations improved with increasing concentration of the selector. Baseline or substantially better resolution for 8 pairs of these Dns-AAs could be achieved. Low CD concentration was enough for the separation of the most apolar Dns-AAs. Chiral discrimination ability of PMMABCD was demonstrated by the separation of an artificial mixture of 8 Dns-AA pairs. PMID:25044151

  5. Ruminal and Abomasal Starch Hydrolysate Infusions Selectively Decrease the Expression of Cationic Amino Acid Transporter mRNA by Small Intestinal Epithelia of Forage-fed Beef Steers

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Although cationic amino acids (CAA) are consid-ered essential to maximize optimal growth of cattle, transporters responsible for CAA absorption by bovine small intestinal epithelia have not been described. This study was conducted to test 2 hypotheses: 1) the duo¬denal, jejunal, and ileal epithelia ...

  6. Mass spectrometry of analytical derivatives. 1. Cyanide cations in the spectra of N- alkyl-N-perfluoroacyl- α-amino acids and their methyl esters.

    PubMed

    Todua, Nino G; Tretyakov, Kirill V; Mikaia, Anzor I

    2015-01-01

    The central mission for the development of the National Institute of Standards and Technology/National Institutes of Health/Environmental Protection Agency Mass Spectral Library is the acquisition of reference gas chromatography-mass spectrometry data for important compounds and their chemical modification products. The addition of reliable reference data of various derivatives of amino acids to The Library, and the study of their behavior under electron ionization conditions may be useful for their identification, structure elucidation and a better understanding of the data obtained when the same derivatives are subjected to other ionization methods. N-Alkyl-N-perfluoroacyl derivatives of amino acids readily produce previously unreported alkylnitrilium cations of composition [HC≡N-alkyl](+). Homologous [HC≡N-aryl](+) cations are typical for corresponding N-aryl analogs. The formation of other ions characteristic for these derivatives involves oxygen rearrangement giving rise to ions [C(n)F(2n+1)-C≡N(+)C(n)H(2n+1)] and [CnF(2n+1)-C≡N(+)-aryl]. The introduction of an N-benzyl substituent in a molecule favors a process producing benzylidene iminium cations. L-Threonine and L-cysteine derivatives exhibit more fragmentation pathways not typical for other α-amino acids; additionally, the N(ω)- amino group in L-lysine directs the dissociation process and provides structural information on the substitution at the amino functions in the molecule. PMID:26307698

  7. Synthesis of cationic single-isomer cyclodextrins for the chiral separation of amino acids and anionic pharmaceuticals.

    PubMed

    Tang, Weihua; Ng, Siu-Choon

    2007-01-01

    We describe a protocol for the synthesis of mono-6(A)-(1-butyl-3-imidazolium)-6(A)-deoxy-beta-cyclodextrin chloride (BIMCD), a cationic, water-soluble cyclodextrin used in the chiral separation of amino acids and anionic pharmaceuticals by capillary electrophoresis. Starting from commercially available chemicals, BIMCD is synthesized in five steps. The first step involves a nucleophilic substitution between p-toluenesulfonyl chloride and imidazole to afford 1-(p-toluenesulfonyl)imidazole (A). In the second step, a nucleophilic substitution between beta-cyclodextrin and A affords mono-6(A)-(p-toluenesulfonyl)-6(A)-deoxy-beta-cyclodextrin (B). In the third step, a nucleophilic substitution between 1-bromobutane and imidazole affords 1-butylimidazole (C). In the fourth step, a nucleophilic addition between A and C affords BIMCD tosylate. In the final step, anion exchange using an ion-exchange resin yields BIMCD as a highly water-soluble solid. Each step takes up to 2 d, including the time required for product purification. The overall protocol requires approximately 6 d. PMID:18079719

  8. Amino Acid Metabolism Disorders

    MedlinePlus

    ... defects & other health conditions > Amino acid metabolism disorders Amino acid metabolism disorders E-mail to a friend Please ... baby’s newborn screening may include testing for certain amino acid metabolism disorders. These are rare health conditions that ...

  9. Plasma amino acids

    MedlinePlus

    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 ...

  10. How Cation-Pi Interactions Enhance and Structure the Binding of Metal Ions to Amino Acids and Peptides. Dialanine Probed by Irmpd Spectroscopy as a Prime Example

    NASA Astrophysics Data System (ADS)

    Dunbar, Robert C.; Steill, Jeffrey; Oomens, Jos

    2010-06-01

    Spectroscopic examination of metalated amino acids and model peptides in the infrared region gives incisive conformational information. The role of cation-pi interactions of the metal ions with aromatic amino acids in structuring the complexes and enforcing particular architectures is being clarified by such experiments using IRMPD action spectroscopy as the experimental probe. The presence of multiple aromatic groups as in dialanine gives particularly stringent conformational stabilization. Comparing spectroscopic peak shifts across a range of alkali and alkaline earth metal ions, ranging from lithium to cesium, and from calcium to barium, allows us to view the systematic relations between normal mode frequencies and ion/peptide interactions. The spectra of the ions were acquired by irradiating the cell of the Fourier-transform ion cyclotron resonance mass spectrometer with infrared light from the FELIX free electron laser at wavelengths in the approximate range 500 to 1900 cm-1.

  11. [Amino acids in saliva].

    PubMed

    Klinger, G; Gruhn, K

    1984-01-01

    Total amino acids in saliva and free and peptide-bound amino acids from 21 saliva samples were determined. The contents of amino acids was 25 mmol/1; total nitrogen content was 78-80 mmol/1. Amino acids consist of Prolin in 25%. Some patients were examined before and after application of the depot estrogen ethinyl estradiosulfonat, which stimulates the assimilation of protein. After application, amino acids increased and the authors found a shift between the single amino acids. Estrogen medication induced an increase in proteins with the character of collagens. Clinical effects are discussed. (author's modified) PMID:6240853

  12. Susceptibility of muridae cell lines to ecotropic murine leukemia virus and the cationic amino acid transporter 1 viral receptor sequences: implications for evolution of the viral receptor.

    PubMed

    Kakoki, Katsura; Shinohara, Akio; Izumida, Mai; Koizumi, Yosuke; Honda, Eri; Kato, Goro; Igawa, Tsukasa; Sakai, Hideki; Hayashi, Hideki; Matsuyama, Toshifumi; Morita, Tetsuo; Koshimoto, Chihiro; Kubo, Yoshinao

    2014-06-01

    Ecotropic murine leukemia viruses (Eco-MLVs) infect mouse and rat, but not other mammalian cells, and gain access for infection through binding the cationic amino acid transporter 1 (CAT1). Glycosylation of the rat and hamster CAT1s inhibits Eco-MLV infection, and treatment of rat and hamster cells with a glycosylation inhibitor, tunicamycin, enhances Eco-MLV infection. Although the mouse CAT1 is also glycosylated, it does not inhibit Eco-MLV infection. Comparison of amino acid sequences between the rat and mouse CAT1s shows amino acid insertions in the rat protein near the Eco-MLV-binding motif. In addition to the insertion present in the rat CAT1, the hamster CAT1 has additional amino acid insertions. In contrast, tunicamycin treatment of mink and human cells does not elevate the infection, because their CAT1s do not have the Eco-MLV-binding motif. To define the evolutionary pathway of the Eco-MLV receptor, we analyzed CAT1 sequences and susceptibility to Eco-MLV infection of other several murinae animals, including the southern vole (Microtus rossiaemeridionalis), large Japanese field mouse (Apodemus speciosus), and Eurasian harvest mouse (Micromys minutus). Eco-MLV infection was enhanced by tunicamycin in these cells, and their CAT1 sequences have the insertions like the hamster CAT1. Phylogenetic analysis of mammalian CAT1s suggested that the ancestral CAT1 does not have the Eco-MLV-binding motif, like the human CAT1, and the mouse CAT1 is thought to be generated by the amino acid deletions in the third extracellular loop of CAT1. PMID:24469466

  13. Proteins and Amino Acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Proteins are the most abundant substances in living organisms and cells. All proteins are constructed from the same twenty amino acids that are linked together by covalent bonds. Shorter chains of two or more amino acids can be linked by covalent bonds to form polypeptides. There are twenty amino...

  14. Transport in Halobacterium Halobium: Light-Induced Cation-Gradients, Amino Acid Transport Kinetics, and Properties of Transport Carriers

    NASA Technical Reports Server (NTRS)

    Lanyi, Janos K.

    1977-01-01

    Cell envelope vesicles prepared from H. halobium contain bacteriorhodopsin and upon illumination protons are ejected. Coupled to the proton motive force is the efflux of Na(+). Measurements of Na-22 flux, exterior pH change, and membrane potential, Delta(psi) (with the dye 3,3'-dipentyloxadicarbocyanine) indicate that the means of Na(+) transport is sodium/proton exchange. The kinetics of the pH changes and other evidence suggests that the antiport is electrogenic (H(+)/Na(++ greater than 1). The resulting large chemical gradient for Na(+) (outside much greater than inside), as well as the membrane potential, will drive the transport of 18 amino acids. The I9th, glutamate, is unique in that its accumulation is indifferent to Delta(psi): this amino acid is transported only when a chemical gradient for Na(+) is present. Thus, when more and more NaCl is included in the vesicles glutamate transport proceeds with longer and longer lags. After illumination the gradient of H+() collapses within 1 min, while the large Na(+) gradient and glutamate transporting activity persists for 10- 15 min, indicating that proton motive force is not necessary for transport. A chemical gradient of Na(+), arranged by suspending vesicles loaded with KCl in NaCl, drives glutamate transport in the dark without other sources of energy, with V(sub max) and K(sub m) comparable to light-induced transport. These and other lines of evidence suggest that the transport of glutamate is facilitated by symport with Na(+), in an electrically neutral fashion, so that only the chemical component of the Na(+) gradient is a driving force.

  15. Amino Acid Crossword Puzzle

    ERIC Educational Resources Information Center

    Sims, Paul A.

    2011-01-01

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

  16. Cationic amino acids specific biomimetic silicification in ionic liquid: a quest to understand the formation of 3-D structures in diatoms.

    PubMed

    Ramanathan, Rajesh; Campbell, Jos L; Soni, Sarvesh K; Bhargava, Suresh K; Bansal, Vipul

    2011-01-01

    The intricate, hierarchical, highly reproducible, and exquisite biosilica structures formed by diatoms have generated great interest to understand biosilicification processes in nature. This curiosity is driven by the quest of researchers to understand nature's complexity, which might enable reproducing these elegant natural diatomaceous structures in our laboratories via biomimetics, which is currently beyond the capabilities of material scientists. To this end, significant understanding of the biomolecules involved in biosilicification has been gained, wherein cationic peptides and proteins are found to play a key role in the formation of these exquisite structures. Although biochemical factors responsible for silica formation in diatoms have been studied for decades, the challenge to mimic biosilica structures similar to those synthesized by diatoms in their natural habitats has not hitherto been successful. This has led to an increasingly interesting debate that physico-chemical environment surrounding diatoms might play an additional critical role towards the control of diatom morphologies. The current study demonstrates this proof of concept by using cationic amino acids as catalyst/template/scaffold towards attaining diatom-like silica morphologies under biomimetic conditions in ionic liquids. PMID:21408611

  17. Disorders of Amino Acid Metabolism

    MedlinePlus

    ... Aspiration Syndrome Additional Content Medical News Disorders of Amino Acid Metabolism By Lee M. Sanders, MD, MPH NOTE: ... Metabolic Disorders Disorders of Carbohydrate Metabolism Disorders of Amino Acid Metabolism Disorders of Lipid Metabolism Amino acids are ...

  18. Amino Acid Metabolism Disorders

    MedlinePlus

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

  19. Amino Acids and Chirality

    NASA Technical Reports Server (NTRS)

    Cook, Jamie E.

    2012-01-01

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

  20. Deletion of cationic amino acid transporter 2 exacerbates dextran sulfate sodium colitis and leads to an IL-17-predominant T cell response.

    PubMed

    Singh, Kshipra; Coburn, Lori A; Barry, Daniel P; Asim, Mohammad; Scull, Brooks P; Allaman, Margaret M; Lewis, Nuruddeen D; Washington, M Kay; Rosen, Michael J; Williams, Christopher S; Chaturvedi, Rupesh; Wilson, Keith T

    2013-08-01

    L-Arginine (L-Arg) is a semiessential amino acid that has altered availability in human ulcerative colitis (UC), a form of inflammatory bowel disease, and is beneficial in murine colitis induced by dextran sulfate sodium (DSS), a model with similarity to UC. We assessed the role of cationic amino acid transporter 2 (CAT2), the inducible transporter of L-Arg, in DSS colitis. Expression of CAT2 was upregulated in tissues from colitic mice and localized predominantly to colonic macrophages. CAT2-deficient (CAT2-/-) mice exposed to DSS exhibited worsening of survival, body weight loss, colon weight, and histological injury. These effects were associated with increased serum L-Arg and decreased tissue L-Arg uptake and inducible nitric oxide synthase protein expression. Clinical benefits of L-Arg supplementation in wild-type mice were lost in CAT2-/- mice. There was increased infiltration of macrophages, dendritic cells, granulocytes, and T cells in colitic CAT2-/- compared with wild-type mice. Cytokine profiling revealed increases in proinflammatory granulocyte colony-stimulating factor, macrophage inflammatory protein-1α, IL-15, and regulated and normal T cell-expressed and -secreted and a shift from an IFN-γ- to an IL-17-predominant T cell response, as well as an increase in IL-13, in tissues from colitic CAT2-/- mice. However, there were no increases in other T helper cell type 2 cytokines, nor was there a global increase in macrophage-derived proinflammatory cytokines. The increase in IL-17 derived from both CD4 and γδ T cells and was associated with colonic IL-6 expression. Thus CAT2 plays an important role in controlling inflammation and IL-17 activation in an injury model of colitis, and impaired L-Arg availability may contribute to UC pathogenesis. PMID:23703655

  1. Hydrogen Bonding, (1)H NMR, and Molecular Electron Density Topographical Characteristics of Ionic Liquids Based on Amino Acid Cations and Their Ester Derivatives.

    PubMed

    Rao, Soniya S; Bejoy, Namitha Brijit; Gejji, Shridhar P

    2015-08-13

    Amino acid ionic liquids (AAILs) have attracted significant attention in the recent literature owing to their ubiquitous applications in diversifying areas of modern chemistry, materials science, and biosciences. The present work focuses on unraveling the molecular interactions underlying AAILs. Electronic structures of ion pairs consisting of amino acid cations ([AA(+)], AA = Gly, Ala, Val, Leu, Ile, Pro, Ser, Thr) and their ester substituted derivatives [AAE(+)] interacting with nitrate anion [NO3(-)] have been obtained from the dispersion corrected M06-2x density functional theory. The formation of ion pair is accompanied by the transfer of proton from quaternary nitrogen to anion facilitated via hydrogen bonding. The [Ile], [Pro], [Ser], and [Thr] and their esters reveal relatively strong inter- as well as intramolecular hydrogen-bonding interactions. Consequently, the hierarchy in binding energies of [AA][NO3] ion pairs and their ester analogues turns out to be [Gly] > [Ala] > [Ser] ∼ [Val] ∼ [Ile] > [Leu] ∼ [Thr] > [Pro]. The work underlines how the interplay of intra- as well as intermolecular hydrogen-bonding interactions in [AA]- and [AAE]-based ILs manifest in their infrared and (1)H NMR spectra. Substitution of -OCH3 functional group in [AA][NO3] ILs lowers the melting point attributed to weaker hydrogen-bonding interactions, making them suitable for room temperature applications. As opposed to gas phase structures, the presence of solvent (DMSO) does not bring about any proton transfer in the ion pairs or their ester analogues. Calculated (1)H NMR chemical shifts of the solvated structures agree well with those from experiment. Correlations of decomposition temperatures in [AA]- and [AAE]-based ILs with binding energies and electron densities at the bond critical point(s) in molecular electron density topography, have been established. PMID:26192454

  2. Effect of excess levels of lysine and leucine in wheat-based, amino acid-fortified diets on the mRNA expression of two selected cationic amino acid transporters in pigs.

    PubMed

    Morales, A; Barrera, M A; Araiza, A B; Zijlstra, R T; Bernal, H; Cervantes, M

    2013-04-01

    An experiment was conducted to evaluate the effect of excess levels of Leu and Lys on the expression of b(0,+) and CAT-1 mRNA in jejunum, liver and the muscles Longissimus dorsi (LDM) and Semitendinosus (STM). Twenty pigs with an average initial BW of 16.4 ± 1.7 kg were used in a Randomized Complete Block. Dietary treatments (T) were as follows: T1, basal diet; T2, basal plus 3.5 g l-Lys/kg diet; T3, basal plus 1.5 g l-Leu/kg diet; T4, basal plus 3.5 g l-Lys plus 1.5 g l-Leu/kg diet. Diets in T1 and T3 met 100% the requirement of Lys for pigs within the 10 to 20 kg body weight range; diets in T2 and T4 contained 35% excess of Lys. Also, diets in T1 and T2 supplied 104%, whereas diets in T3 and T4 supplied 116% the requirement of Leu. The expression of b(0,+) in jejunum was reduced (p = 0.002) because of the supplementation of l-Leu, but l-Lys supplementation had no effect (p = 0.738). In contrast, the expression of b(0,+) in STM (p = 0.012) and liver (p = 0.095) was reduced by the high level of Lys, but Leu had no effect (p > 0.100). CAT-1 expression in STM increased by high Lys (p = 0.023) and Leu (p = 0.007) levels. In liver, the expression of CAT-1 substantially increased (p = 0.001) because of Lys. In conclusion, excess levels of dietary Lys and Leu affect the expression of cationic amino acid transporters, and this effect varies depending on the studied tissue. PMID:22211733

  3. Brain amino acid sensing.

    PubMed

    Tsurugizawa, T; Uneyama, H; Torii, K

    2014-09-01

    The 20 different amino acids, in blood as well as in the brain, are strictly maintained at the same levels throughout the day, regardless of food intake. Gastric vagal afferents only respond to free glutamate and sugars, providing recognition of food intake and initiating digestion. Metabolic control of amino acid homeostasis and diet-induced thermogenesis is triggered by this glutamate signalling in the stomach through the gut-brain axis. Rats chronically fed high-sugar and high-fat diets do not develop obesity when a 1% (w/v) monosodium glutamate (MSG) solution is available in a choice paradigm. Deficiency of the essential amino acid lysine (Lys) induced a plasticity in rats in response to Lys. This result shows how the body is able to identify deficient nutrients to maintain homeostasis. This plastic effect is induced by activin A activity in the brain, particularly in certain neurons in the lateral hypothalamic area (LHA) which is the centre for amino acid homeostasis and appetite. These neurons respond to glutamate signalling in the oral cavity by which umami taste is perceived. They play a quantitative role in regulating ingestion of deficient nutrients, thereby leading to a healthier life. After recovery from malnutrition, rats prefer MSG solutions, which serve as biomarkers for protein nutrition. PMID:25200295

  4. The structure of the gene ATRC1 coding for a cationic amino acid transport system in man: Molecular studies in lysinuric protein intolerance

    SciTech Connect

    Incerti, B.; Sebastio, G.; Parenti, G.

    1994-09-01

    The human cDNA (ATRC1) homologue of a murine gene encoding for a transporter specific for cationic amino acid (CAA) has been isolated. ATRC1 stimulates the uptake of CAA and shows the kinetic properties of system y+ when expressed in frog oocytes. To characterize the organization of the ATRC1 gene, a {lambda} phages genomic DNA library has been screened using an ATRC1 full length cDNA clone as a probe. Nine positive phages have been subcloned in plasmids and sequenced using cDNA specific primers to identify intron-exon junctions. The ATRC1 gene consists of 13 exons with an alternative first exon. Analysis of the intron/exon boundaries showed canonical sequences at the splice junction sites. ATRC1 expression pattern has been analyzed by RT-PCR. ATRC1 is expressed in adult fibroblasts and enterocytes, in fetal kidney, brain and heart, and in lymphoblastoid cell lines. The knowledge of structure and organization of ATRC1 can help in studying inborn errors of CAA transport. The best characterized among these diseases is Lysinuric Protein Intolerance (LPI) a multisystem disorder with impaired formation of urea and hyperammonemia after protein ingestion. Linkage analysis performed on 10 LPI patients from 9 Italian families using two intragenic RFLPs revealed 3 informative families and no recombinations. Using the CA-repeat microsatellite D12S120 (2 cM far from ATRC-1 locus) we found 7 informative families and 3 recombinational events. The sequence of the entire coding region of an LPI patient failed to show mutations. The data so far obtained do not seem to support the hypothesis that ATRC1 is the LPI gene.

  5. Amino acid analysis.

    PubMed

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

    2001-05-01

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

  6. Amino acid imbalance in cystinuria

    PubMed Central

    Asatoor, A. M.; Freedman, P. S.; Gabriel, J. R. T.; Milne, M. D.; Prosser, D. I.; Roberts, J. T.; Willoughby, C. P.

    1974-01-01

    After oral ingestion of a free amino acid mixture by three cystinuric patients, plasma increments of lysine and arginine were lower and those of many other amino acids were significantly higher than those found in control subjects. Similar results were obtained in control subjects after amino acid imbalance had been artificially induced by the omission of cystine, lysine, and arginine from the amino acid mixture. Especially high increments of alanine and proline provided the best evidence of amino acid imbalance caused by a temporary lysine and, to a lesser extent, arginine and cystine deficit. No such amino acid imbalance was found to occur in the cystinuric patients after ingestion of whole protein, indicating that absorption of oligopeptides produced by protein digestion provided a balanced physiological serum amino acid increment. This is considered to explain the lack of any unequivocal nutritional deficit in cystinuric patients despite poor absorption of the essential free amino acid, lysine. PMID:4411931

  7. Amino acids in Arctic aerosols

    NASA Astrophysics Data System (ADS)

    Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

    2012-11-01

    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 and 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 volcanic emissions.

  8. Amino acids in Arctic aerosols

    NASA Astrophysics Data System (ADS)

    Scalabrin, E.; Zangrando, R.; Barbaro, E.; Kehrwald, N. M.; Gabrieli, J.; Barbante, C.; Gambaro, A.

    2012-07-01

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

  9. Synthesis of amino acids

    DOEpatents

    Davis, J.W. Jr.

    1979-09-21

    A method is described for synthesizing amino acids preceding through novel intermediates of the formulas: R/sub 1/R/sub 2/C(OSOC1)CN, R/sub 1/R/sub 2/C(C1)CN and (R/sub 1/R/sub 2/C(CN)O)/sub 2/SO wherein R/sub 1/ and R/sub 2/ are each selected from hydrogen and monovalent hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  10. Excited triplet state of N-(9-methylpurin-6-yl)pyridinium cation as an efficient photosensitizer in the oxidation of sulfur-containing amino acids. Laser flash and steady-state photolysis studies

    SciTech Connect

    Marciniak, B. Univ. of Notre Dame, IN ); Hug, G.L.; Bobrowski, K. ); Rozwadowski, J. )

    1995-01-11

    In this paper, we present and discuss the results of a detailed mechanistic study of the photosensitized oxidation of sulfur-containing amino acids by N-(9-methylpurin-6-yl)pyridinium cations in aqueous solution. The results provide data on the photoreactivity of the pyridinium salts (derived from the purine bases) in the presence of the electron donors such as sulfur-containing organic compounds and give new experimental evidence for the general mechanism of the sensitized photooxidation of thioethers proposed previously. 39 refs., 6 figs., 2 tabs.

  11. Effect of Baicalin-loaded PEGylated cationic solid lipid nanoparticles modified by OX26 antibody on regulating the levels of baicalin and amino acids during cerebral ischemia-reperfusion in rats.

    PubMed

    Liu, Zhidong; Zhang, Li; He, Qiansong; Liu, Xiaolei; Okeke, Chukwunweike Ikechukwu; Tong, Ling; Guo, Lili; Yang, Hongyun; Zhang, Qian; Zhao, Hainan; Gu, Xing

    2015-07-15

    Baicalin has many pharmacological activities, including neuroprotective function against ischemia and neurodegeneration. In our previous study, we found that Baicalin-loaded PEGylated cationic solid lipid nanoparticles modified by OX26 antibody (OX26-PEG-CSLN) might be a promising carrier to deliver drugs across the blood-brain barrier for the treatment of brain diseases. So, the aim of this present study was to further elucidate the mechanisms of OX26-PEG-CSLN cerebral ischemia protection by monitoring the changes of extracellular amino acids. In addition, we investigated the effect of OX26-PEG-CSLN on the excitotoxic neuronal injury as well as the pharmacokinetic profiles of baicalin in cerebrospinal fluid during ischemia-reperfusion period. The cerebrospinal fluid was collected by a microdialysis technique and divided into two parts - one part for pharmacokinetic study of baicalin using LC-MS/MS method and the other for pharmacodynamic study which was done by pre- column derivatization of the amino acids and analysis using a high-performance liquid chromatography with fluorescence detector (HPLC-FLD). The pharmacokinetic study showed that the AUC value of OX26-PEG-CSLN was 5.69-fold higher than that of the baicalin solution (Sol) (P<0.05) and the Cmax value of OX26-PEG-CSLN was 6.84-fold higher than that of the Sol (P<0.05). Moreover, the extracellular levels of glutamate (Glu), aspartic acid (Asp), glycine (Gly), taurine (Tau) and γ-aminobutyric acid (GABA) were measured for monitoring the imbalance of amino acids caused by ischemia and reperfusion. The excitotoxic index (EI) was also calculated for evaluating the imbalance between excitatory amino acid and inhibitory amino acid. The pharmacodynamic study showed that OX26-PEG-CSLN had stronger effect than Sol in reducing the content of aspartic, glutamic acid and increasing the concentrations of glycine, taurine and γ-aminobutyric acid during ischemia-reperfusion period. In conclusion, OX26-PEG-CSLN improved

  12. Hair and amino acids: the interactions and the effects.

    PubMed

    Oshimura, Eiko; Abe, Hiroshi; Oota, Rina

    2007-01-01

    The interaction and the function of some amino acids in hair care applications are discussed. When amino acids are applied to hair in the form of simple aqueous solution, uptake of the amino acids is mainly controlled by ionic equilibrium. When amino acids were incorporated in a hair conditioner, the result was quite different, suggesting the importance of interaction between the amino acids and the cationic surfactants. Uptake of pyrrolidone carboxylic acid (PCA), a derivative of glutamic acid, is enhanced by combining with arginine, an amino with strong affinity towards hair. Effects of some amino acids on bleached/dyed hair are described. A hair conditioner incorporated with alanine improves hair surface hydrophobicity of bleach-damaged hair. Histidine and phenylalanine improve tensile strength. PCA was proved to be effective to improve color-retention of dyed hair. PMID:17728935

  13. Microfluidics in amino acid analysis.

    PubMed

    Pumera, Martin

    2007-07-01

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

  14. Self-Assembled Cationic Biodegradable Nanoparticles from pH-Responsive Amino-Acid-Based Poly(Ester Urea Urethane)s and Their Application As a Drug Delivery Vehicle.

    PubMed

    He, Mingyu; Potuck, Alicia; Kohn, Julie C; Fung, Katharina; Reinhart-King, Cynthia A; Chu, Chih-Chang

    2016-02-01

    The objective of this study is to develop a new family of biodegradable and biologically active copolymers and their subsequent self-assembled cationic nanoparticles as better delivery vehicles for anticancer drugs to achieve the synergism between the cytotoxicity effects of the loaded drugs and the macrophage inflammatory response of the delivery vehicle. This family of cationic nanoparticles was formulated from a new family of amphiphilic cationic Arginine-Leucine (Arg-Leu)-based poly(ester urea urethane) (Arg-Leu PEUU) synthesized from four building blocks (amino acids, diols, glycerol α-monoallyl ether, and 1,6 hexamethylene diisocyanate). The chemical, physical, and biological properties of Arg-Leu PEUU biomaterials can be tuned by controlling the feed ratio of the four building blocks. The Arg-Leu PEUU copolymers have weight-average molecular weights from 13.4 to 16.8 kDa and glass-transition temperatures from -3.4 to -4.6 °C. The self-assembled cationic nanoparticles (Arg-Leu PEUU NPs) were prepared using a facile dialysis method. Arg-Leu PEUU NPs have average diameters ranging from 187 to 272 nm, show good biocompatibility with 3T3 fibroblasts, and they support bovine aortic endothelial cell (BAEC) proliferation and adhesion. Arg-Leu PEUU NPs also enhanced the macrophages' production of tumor necrosis factor-α (TNF-α) and nitric oxide (NO), but produced relatively low levels of interleukin-10 (IL-10), and therefore, the antitumor activity of macrophages might be enhanced. Arg-Leu PEUU NPs were taken up by HeLa cells after 4 h of incubation. The in vitro hemolysis assay showed the cationic Arg-Leu PEUU NPs increased their chance of endosomal escape at a more acidic pH. Doxorubicin (DOX) was successfully incorporated into the Arg-Leu PEUU NPs, and the DOX-loaded Arg-Leu PEUU NPs exhibited a pH-dependent drug release profile with accelerated release kinetics in a mild acidic condition. The DOX-loaded 6-Arg-4-Leu-4 A/L-2/1 NPs showed higher HeLa cell

  15. Amino Acids from a Comet

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elisla

    2009-01-01

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

  16. Treatment of Amino Acid Metabolism Disorders

    MedlinePlus

    ... Treatment of amino acid metabolism disorders Treatment of amino acid metabolism disorders E-mail to a friend Please ... this page It's been added to your dashboard . Amino acid metabolism disorders are rare health conditions that affect ...

  17. Cationic lipid-mediated nucleic acid delivery: beyond being cationic.

    PubMed

    Rao, N Madhusudhana

    2010-03-01

    Realization of the potential of nucleic acids as drugs is intricately linked to their in vivo delivery. Cationic lipids demonstrated tremendous potential as safe, efficient and scalable in vitro carriers of nucleic acids. For in vivo delivery of nucleic acids, the extant two component liposomal preparations consisting of cationic lipids and nucleic acids have been largely found to be insufficient. Being a soft matter, liposomes readily respond to many physiological variables leading to complex component and morphological changes, thus confounding the efforts in a priori identification of a "competent" formulation. In the recent past many chemical moieties that provide advantage in facing the challenges of barriers in vivo, were incorporated into cationic lipids to improve the transfection efficiency. The cationic lipids, essential for DNA condensation and protection, definitely require additional components to be efficient in vivo. In addition, formulations of cationic lipid carriers with non-lipidic components, mainly peptides, have demonstrated success in in vivo transfection. The present review describes some recent successes of in vivo nucleic acid delivery by cationic lipids. PMID:20060819

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

    NASA Technical Reports Server (NTRS)

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

    1994-01-01

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

  19. Binding of cationic peptides (KX)4K to DPPG bilayers. Increasing the hydrophobicity of the uncharged amino acid X drives formation of membrane bound β-sheets: A DSC and FT-IR study.

    PubMed

    Hädicke, André; Blume, Alfred

    2016-06-01

    The binding of cationic peptides of the sequence (KX)4K to lipid vesicles of negatively charged dipalmitoyl-phosphatidylglycerol (DPPG) was investigated by differential scanning calorimetry (DSC) and temperature dependent Fourier-transformed infrared (FT-IR) spectroscopy. The hydrophobicity of the uncharged amino acid X was changed from G (glycine) over A (alanine), Abu (α-aminobutyric acid), V (valine) to L (leucine). The binding of the peptides caused an increase of the phase transition temperature (Tm) of DPPG by up to 20°C. The shift depended on the charge ratio and on the hydrophobicity of the amino acid X. Unexpectedly, the upward shift of Tm increased with increasing hydrophobicity of X. FT-IR spectroscopy showed a shift of the CH2 stretching vibrations of DPPG to lower frequency, particularly for bilayers in the liquid-crystalline phase, indicating an ordering of the hydrocarbon chains when the peptides were bound. Changes in the lipid C=O vibrational band indicated a dehydration of the lipid headgroup region after peptide binding. (KG)4K was bound in an unordered structure at all temperatures. All other peptides formed intermolecular antiparallel β-sheets, when bound to gel phase DPPG. However, for (KA)4K and (KAbu)4K, the β-sheets converted into an unordered structure above Tm. In contrast, the β-sheet structures of (KV)4K and (KL)4K remained stable even at 80°C when bound to the liquid-crystalline phase of DPPG. Strong aggregation of DPPG vesicles occurred after peptide binding. For the aggregates, we suggest a structure, where aggregated single β-sheets are sandwiched between opposing DPPG bilayers with a dehydrated interfacial region. PMID:26903220

  20. DNA pre-condensation with an amino acid-based cationic amphiphile. A viable approach for liposome-based gene delivery.

    PubMed

    Rosa, Mónica; Penacho, Nuno; Simöes, Sérgio; Lima, Maria C P; Lindman, Björn; Miguel, Maria G

    2008-01-01

    A study related to the development and characterization of a new gene delivery system was performed. The approach consists in both the pre-condensation of plasmid DNA with an arginine-based cationic surfactant, arginine-N-lauroyl amide dihydrochloride (ALA), which was found not to be toxic, and the incorporation of the blood protein transferrin (Tf) into the formulations. Two cationic liposome formulations were used, one composed of a mixture of dioleoyl trimethylammoniopropane and cholesterol (DOTAP:Chol) and the other a pH sensitive formulation constituted of DOTAP, Chol, Dioleoyl phosphatidylethanolamine (DOPE) and cholesteryl hemisuccinate (CHEMS). Particles with different ALA/DNA and cationic lipid/DNA charge ratios were produced and a physicochemical characterization of the systems developed was performed. DNA conformational changes in the presence of ALA were studied by Circular Dichroism (CD) and the ALA binding to DNA was followed by surface tension measurements. Insight into the structure and morphology of the various ALA-complexes (complexes composed of ALA, DNA, Tf and liposomes) was obtained by cryogenic-Transmission Electron Microscopy (cryo-TEM) and the sizes of the ALA-complexes were determined through Photon Correlation Spectroscopy (PCS). We found that the transfection capacity of these systems is directly related with the presence of ALA and the lipidic composition. Complexes based on the pH sensitive liposome formulation present better transfection profiles. The correlation between the inner structure, density and size of the ALA-complexes and their biological activity is discussed. Overall, we demonstrate that the presence of ALA improves the transfection efficiency when conjugated with cationic liposome systems. PMID:18097953

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

    PubMed Central

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

    2015-01-01

    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. PMID:25915115

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

    PubMed

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

    2015-01-01

    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. PMID:25915115

  3. Combinatorics of aliphatic amino acids.

    PubMed

    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. PMID:21120449

  4. Amino Acid Transport in Pseudomonas aeruginosa

    PubMed Central

    Kay, W. W.; Gronlund, Audrey F.

    1969-01-01

    Properties of the transport systems for amino acids in Pseudomonas aeruginosa were investigated. Exogenous 14C-labeled amino acids were shown to equilibrate with the internal native amino acid pool prior to incorporation into protein. When added at low external concentrations, the majority of the amino acids examined entered the protein of the cell unaltered. The rates of amino acid transport, established at low concentrations with 18 commonly occurring amino acids, varied as much as 40-fold. The transport process became saturated at high external amino acid concentrations, was temperature-sensitive, and was inhibited by sodium azide and iodoacetamide. Intracellular to extracellular amino acid ratios of 100- to 300-fold were maintained during exponential growth of the population in a glucose minimal medium. When the medium became depleted of glucose, neither extracellular nor intracellular amino acids could be detected. PMID:4974392

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

    NASA Technical Reports Server (NTRS)

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

    1983-01-01

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

  6. Nonprotein Amino Acids in the Murchison Meteorite

    PubMed Central

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

    1971-01-01

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

  7. [Inherited amino acid transport disorders].

    PubMed

    Igarashi, Y; Tada, K

    1992-07-01

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

  8. Amino acids in sheep production.

    PubMed

    McCoard, Susan A; Sales, Francisco A; Sciascia, Quentin L

    2016-01-01

    Increasing production efficiency with a high standard of animal welfare and respect for the environment is a goal of sheep farming systems. Substantial gains in productivity have been achieved through improved genetics, nutrition and management changes; however the survival and growth performance of multiple-born lambs still remains a problem. This is a significant production efficiency and animal well-being issue. There is a growing body of evidence that some amino acids have a role in regulating growth, reproduction and immunity through modulation of metabolic and cell signaling pathways. The purpose of this review is to provide an overview of what is currently known about the role of amino acids in sheep production and the potential for supplementation strategies to influence on-farm survival and growth of lambs. PMID:26709661

  9. Intestinal metabolism of sulfur amino acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gastrointestinal tract (GIT) serves a key function in the digestion of dietary protein and absorption of amino acids. However, the GIT is also an important site of amino acid metabolism in the body. Methionine is an indispensable amino acid and must be supplied in the diet. In addition, consider...

  10. Amino acid analyses of Apollo 14 samples.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    Detection limits were between 300 pg and 1 ng for different amino acids, in an analysis by gas-liquid chromatography of water extracts from Apollo 14 lunar fines in which amino acids were converted to their N-trifluoro-acetyl-n-butyl esters. Initial analyses of water and HCl extracts of sample 14240 and 14298 samples showed no amino acids above background levels.

  11. Unnatural reactive amino acid genetic code additions

    SciTech Connect

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

    2011-08-09

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

  12. Unnatural reactive amino acid genetic code additions

    SciTech Connect

    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.

  13. Unnatural reactive amino acid genetic code additions

    SciTech Connect

    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.

  14. Unnatural reactive amino acid genetic code additions

    SciTech Connect

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

    2011-02-15

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

  15. Amino acids as antioxidants for frying oil

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  16. Symmetry scheme for amino acid codons

    NASA Astrophysics Data System (ADS)

    Balakrishnan, J.

    2002-02-01

    Group theoretical concepts are invoked in a specific model to explain how only twenty amino acids occur in nature out of a possible sixty four. The methods we use enable us to justify the occurrence of the recently discovered 21st amino acid selenocysteine, and also enables us to predict the possible existence of two more, as yet undiscovered amino acids.

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

    PubMed

    Mitsuhashi, Satoshi

    2014-04-01

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

  18. Pairwise amino acid secondary structural propensities

    NASA Astrophysics Data System (ADS)

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

    2015-04-01

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

  19. Molecular cloning of mouse amino acid transport system B0, a neutral amino acid transporter related to Hartnup disorder.

    PubMed

    Bröer, Angelika; Klingel, Karin; Kowalczuk, Sonja; Rasko, John E J; Cavanaugh, Juleen; Bröer, Stefan

    2004-06-01

    Resorption of amino acids in kidney and intestine is mediated by transporters, which prefer groups of amino acids with similar physico-chemical properties. It is generally assumed that most neutral amino acids are transported across the apical membrane of epithelial cells by system B(0). Here we have characterized a novel member of the Na(+)-dependent neurotransmitter transporter family (B(0)AT1) isolated from mouse kidney, which shows all properties of system B(0). Flux experiments showed that the transporter is Na(+)-dependent, electrogenic, and actively transports most neutral amino acids but not anionic or cationic amino acids. Superfusion of mB(0)AT1-expressing oocytes with neutral amino acids generated inward currents, which were proportional to the fluxes observed with labeled amino acids. In situ hybridization showed strong expression in intestinal microvilli and in the proximal tubule of the kidney. Expression of mouse B(0)AT1 was restricted to kidney, intestine, and skin. It is generally assumed that mutations of the system B(0) transporter underlie autosomal recessive Hartnup disorder. In support of this notion mB(0)AT1 is located on mouse chromosome 13 in a region syntenic to human chromosome 5p15, the locus of Hartnup disorder. Thus, the human homologue of this transporter is an excellent functional and positional candidate for Hartnup disorder. PMID:15044460

  20. Sugar amino acids in designing new molecules.

    PubMed

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

    2005-03-01

    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. This article describes some of our works on various sugar amino acids and many other related building blocks, like furan amino acids, pyrrole amino acids etc. used in wide-ranging peptidomimetic studies. PMID:16133829

  1. miR-122, a mammalian liver-specific microRNA, is processed from hcr mRNA and may downregulate the high affinity cationic amino acid transporter CAT-1.

    PubMed

    Chang, Jinhong; Nicolas, Emmanuelle; Marks, Debora; Sander, Chris; Lerro, Anthony; Buendia, Marie Annick; Xu, Chunxiao; Mason, William S; Moloshok, Thomas; Bort, Roque; Zaret, Kenneth S; Taylor, John M

    2004-07-01

    These studies show that miR-122, a 22-nucleotide microRNA, is derived from a liver-specific noncoding polyadenylated RNA transcribed from the gene hcr. The exact sequence of miR-122 as well as the adjacent secondary structure within the hcr mRNA are conserved from mammalian species back to fish. Levels of miR-122 in the mouse liver increase to half maximal values around day 17 of embryogenesis, and reach near maximal levels of 50,000 copies per average cell before birth. Lewis et al. (2003) predicted the cationic amino acid transporter (CAT-1 or SLC7A1) as a miR-122 target. CAT-1 protein and its mRNA are expressed in all mammalian tissues but with lower levels in adult liver. Furthermore, during mouse liver development CAT-1 mRNA decreases in an almost inverse correlation with miR-122. Eight potential miR-122 target sites were predicted within the human CAT-1 mRNA, with six in the 3'-untranslated region. Using a reporter construct it was found that just three of the predicted sites, linked in a 400-nucleotide sequence from human CAT-1, acted with synergy and were sufficient to strongly inhibit protein synthesis and reduce mRNA levels. In summary, these studies followed the accumulation during development of miR-122 from its mRNA precursor, hcr, through to identification of what may be a specific mRNA target, CAT-1. PMID:17179747

  2. Recombinant adeno-associated virus-mediated high-efficiency, transient expression of the murine cationic amino acid transporter (ecotropic retroviral receptor) permits stable transduction of human HeLa cells by ecotropic retroviral vectors.

    PubMed Central

    Bertran, J; Miller, J L; Yang, Y; Fenimore-Justman, A; Rueda, F; Vanin, E F; Nienhuis, A W

    1996-01-01

    Adeno-associated virus has a broad host range, is nonpathogenic, and integrates into a preferred location on chromosome 19, features that have fostered development of recombinant adeno-associated viruses (rAAV) as gene transfer vectors for therapeutic applications. We have used an rAAV to transfer and express the murine cationic amino acid transporter which functions as the ecotropic retroviral receptor, thereby rendering human cells conditionally susceptible to infection by an ecotropic retroviral vector. The proportion of human HeLa cells expressing the receptor at 60 h varied as a function of the multiplicity of infection (MOI) with the rAAV. Cells expressing the ecotropic receptor were efficiently transduced with an ecotropic retroviral vector encoding a nucleus-localized form of beta-galactosidase. Cells coexpressing the ecotropic receptor and nucleus-localized beta-galactosidase were isolated by fluorescence-activated cell sorting, and cell lines were recovered by cloning at limiting dilution. After growth in culture, all clones contained the retroviral vector genome, but fewer than 10% (3 of 47) contained the rAAV genome and continued to express the ecotropic receptor. The ecotropic receptor coding sequences in the rAAV genome were under the control of a tetracycline-modulated promoter. In the presence of tetracycline, receptor expression was low and the proportion of cells transduced by the ecotropic retroviral vector was decreased. Modulation of receptor expression was achieved with both an episomal and an integrated form of the rAAV genome. These data establish that functional gene expression from an rAAV genome can occur transiently without genome integration. PMID:8794313

  3. Amino-acid contamination of aqueous hydrochloric acid.

    NASA Technical Reports Server (NTRS)

    Wolman, Y.; Miller, S. L.

    1971-01-01

    Considerable amino-acid contamination in commercially available analytical grade hydrochloric acid (37% HCl) was found. One bottle contained 8,300 nmol of amino-acids per liter. A bottle from another supplier contained 6,700 nmol per liter. The contaminants were mostly protein amino-acids and several unknowns. Data on the volatility of the amino-acids during HCl distillation were also obtained.

  4. Cationic Lipid-Based Nucleic Acid Vectors.

    PubMed

    Jubeli, Emile; Goldring, William P D; Pungente, Michael D

    2016-01-01

    The delivery of nucleic acids into cells remains an important laboratory cell culture technique and potential clinical therapy, based upon the initial cellular uptake, then translation into protein (in the case of DNA), or gene deletion by RNA interference (RNAi). Although viral delivery vectors are more efficient, the high production costs, limited cargo capacity, and the potential for clinical adverse events make nonviral strategies attractive. Cationic lipids are the most widely applied and studied nonviral vectors; however, much remains to be solved to overcome limitations of these systems. Advances in the field of cationic lipid-based nucleic acid (lipoplex) delivery rely upon the development of robust and reproducible lipoplex formulations, together with the use of cell culture assays. This chapter provides detailed protocols towards the formulation, delivery, and assessment of in vitro cationic lipid-based delivery of DNA. PMID:27436310

  5. Enantiomeric excesses in meteoritic amino acids

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Pizzarello, S.

    1997-01-01

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

  6. Amino acids in the Tagish Lake Meteorite

    NASA Technical Reports Server (NTRS)

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

    2002-01-01

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

  7. Amino acids precursors in lunar finds

    NASA Technical Reports Server (NTRS)

    Fox, S. W.; Harada, K.; Hare, P. E.; Hinsch, G.; Mueller, G.

    1975-01-01

    The consistent pattern is discussed of amino acids found in lunar dust from Apollo missions. The evidence indicates that compounds yielding amino acids were implanted into the surface of the moon by the solar wind, and the kind and amounts of amino acids found on the moon are closely similar to those found in meteorites. It is concluded that there is a common cosmochemical pattern for the moom and meteorites, and this offers evidence of a common course of cosmochemical reactions for carbon.

  8. Regulation of the proteome by amino acids.

    PubMed

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

    2016-03-01

    Besides their main contribution as substrates for protein synthesis, amino acids as signaling molecules could exert some regulatory functions on protein synthesis and/or proteolysis that have been emphasized in a number of recent studies. Several publications have highlighted supplemental roles of those amino acids in protein metabolism as well as in immunity, heat shock response, or apoptosis processes. In this way, via their regulatory properties, selected amino acids (such as leucine, glutamine, arginine, citrulline, or methionine) directly influence the proteome. In this review, we are proposing an overview of the regulation of the proteome by amino acids in mammals. PMID:26786846

  9. α-Amino Acid-Isosteric α-Amino Tetrazoles.

    PubMed

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

    2016-02-24

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

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

    PubMed

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

    2015-02-25

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

  11. Orientation preferences of backbone secondary amide functional groups in peptide nucleic acid complexes: quantum chemical calculations reveal an intrinsic preference of cationic D-amino acid-based chiral PNA analogues for the P-form.

    PubMed

    Topham, Christopher M; Smith, Jeremy C

    2007-02-01

    Geometric descriptions of nonideal interresidue hydrogen bonding and backbone-base water bridging in the minor groove are established in terms of polyamide backbone carbonyl group orientation from analyses of residue junction conformers in experimentally determined peptide nucleic acid (PNA) complexes. Two types of interresidue hydrogen bonding are identified in PNA conformers in heteroduplexes with nucleic acids that adopt A-like basepair stacking. Quantum chemical calculations on the binding of a water molecule to an O2 base atom in glycine-based PNA thymine dimers indicate that junctions modeled with P-form backbone conformations are lower in energy than a dimer comprising the predominant conformation observed in A-like helices. It is further shown in model systems that PNA analogs based on D-lysine are better able to preorganize in a conformation exclusive to P-form helices than is glycine-based PNA. An intrinsic preference for this conformation is also exhibited by positively charged chiral PNA dimers carrying 3-amino-D-alanine or 4-aza-D-leucine residue units that provide for additional rigidity by side-chain hydrogen bonding to the backbone carbonyl oxygen. Structural modifications stabilizing P-form helices may obviate the need for large heterocycles to target DNA pyrimidine bases via PNA.DNA-PNA triplex formation. Quantum chemical modeling methods are used to propose candidate PNA Hoogsteen strand designs. PMID:17071666

  12. Regulation of renal amino acid transporters during metabolic acidosis.

    PubMed

    Moret, Caroline; Dave, Mital H; Schulz, Nicole; Jiang, Jean X; Verrey, Francois; Wagner, Carsten A

    2007-02-01

    The kidney plays a major role in acid-base homeostasis by adapting the excretion of acid equivalents to dietary intake and metabolism. Urinary acid excretion is mediated by the secretion of protons and titratable acids, particularly ammonia. NH(3) is synthesized in proximal tubule cells from glutamine taken up via specific amino acid transporters. We tested whether kidney amino acid transporters are regulated in mice in which metabolic acidosis was induced with NH(4)Cl. Blood gas and urine analysis confirmed metabolic acidosis. Real-time RT-PCR was performed to quantify the mRNAs of 16 amino acid transporters. The mRNA of phosphoenolpyruvate carboxykinase (PEPCK) was quantified as positive control for the regulation and that of GAPDH, as internal standard. In acidosis, the mRNA of kidney system N amino acid transporter SNAT3 (SLC38A3/SN1) showed a strong induction similar to that of PEPCK, whereas all other tested mRNAs encoding glutamine or glutamate transporters were unchanged or reduced in abundance. At the protein level, Western blotting and immunohistochemistry demonstrated an increased abundance of SNAT3 and reduced expression of the basolateral cationic amino acid/neutral amino acid exchanger subunit y(+)-LAT1 (SLC7A7). SNAT3 was localized to the basolateral membrane of the late proximal tubule S3 segment in control animals, whereas its expression was extended to the earlier S2 segment of the proximal tubule during acidosis. Our results suggest that the selective regulation of SNAT3 and y(+)LAT1 expression may serve a major role in the renal adaptation to acid secretion and thus for systemic acid-base balance. PMID:17003226

  13. Research for amino acids in lunar samples.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

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

  14. Amino acid regulation of gene expression.

    PubMed Central

    Fafournoux, P; Bruhat, A; Jousse, C

    2000-01-01

    The impact of nutrients on gene expression in mammals has become an important area of research. Nevertheless, the current understanding of the amino acid-dependent control of gene expression is limited. Because amino acids have multiple and important functions, their homoeostasis has to be finely maintained. However, amino-acidaemia can be affected by certain nutritional conditions or various forms of stress. It follows that mammals have to adjust several of their physiological functions involved in the adaptation to amino acid availability by regulating the expression of numerous genes. The aim of the present review is to examine the role of amino acids in regulating mammalian gene expression and protein turnover. It has been reported that some genes involved in the control of growth or amino acid metabolism are regulated by amino acid availability. For instance, limitation of several amino acids greatly increases the expression of the genes encoding insulin-like growth factor binding protein-1, CHOP (C/EBP homologous protein, where C/EBP is CCAAT/enhancer binding protein) and asparagine synthetase. Elevated mRNA levels result from both an increase in the rate of transcription and an increase in mRNA stability. Several observations suggest that the amino acid regulation of gene expression observed in mammalian cells and the general control process described in yeast share common features. Moreover, amino acid response elements have been characterized in the promoters of the CHOP and asparagine synthetase genes. Taken together, the results discussed in the present review demonstrate that amino acids, by themselves, can, in concert with hormones, play an important role in the control of gene expression. PMID:10998343

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 n...

  16. Alkaline earth cation extraction from acid solution

    DOEpatents

    Dietz, Mark; Horwitz, E. Philip

    2003-01-01

    An extractant medium for extracting alkaline earth cations from an aqueous acidic sample solution is described as are a method and apparatus for using the same. The separation medium is free of diluent, free-flowing and particulate, and comprises a Crown ether that is a 4,4'(5')[C.sub.4 -C.sub.8 -alkylcyclohexano]18-Crown-6 dispersed on an inert substrate material.

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

    PubMed

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

    2016-09-01

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

  18. Human Protein and Amino Acid Requirements.

    PubMed

    Hoffer, L John

    2016-05-01

    Human protein and amino acid nutrition encompasses a wide, complex, frequently misunderstood, and often contentious area of clinical research and practice. This tutorial explains the basic biochemical and physiologic principles that underlie our current understanding of protein and amino acid nutrition. The following topics are discussed: (1) the identity, measurement, and essentiality of nutritional proteins; (2) the definition and determination of minimum requirements; (3) nutrition adaptation; (4) obligatory nitrogen excretion and the minimum protein requirement; (5) minimum versus optimum protein intakes; (6) metabolic responses to surfeit and deficient protein intakes; (7) body composition and protein requirements; (8) labile protein; (9) N balance; (10) the principles of protein and amino acid turnover, including an analysis of the controversial indicator amino acid oxidation technique; (11) general guidelines for evaluating protein turnover articles; (12) amino acid turnover versus clearance; (13) the protein content of hydrated amino acid solutions; (14) protein requirements in special situations, including protein-catabolic critical illness; (15) amino acid supplements and additives, including monosodium glutamate and glutamine; and (16) a perspective on the future of protein and amino acid nutrition research. In addition to providing practical information, this tutorial aims to demonstrate the importance of rigorous physiologic reasoning, stimulate intellectual curiosity, and encourage fresh ideas in this dynamic area of human nutrition. In general, references are provided only for topics that are not well covered in modern textbooks. PMID:26796095

  19. 6th Amino Acid Assessment Workshop

    Technology Transfer Automated Retrieval System (TEKTRAN)

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

  20. The Apollo Program and Amino Acids

    ERIC Educational Resources Information Center

    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. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Amino acids. 172.320 Section 172.320 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO FOOD FOR HUMAN CONSUMPTION Special Dietary and Nutritional Additives § 172.320 Amino acids. The food additive...

  2. Protein biosynthesis with conformationally restricted amino acids

    SciTech Connect

    Mendel, D. Lawrence Berkeley Lab., CA ); Ellman, J.; Schultz, P.G. )

    1993-05-19

    The incorporation of conformationally constrained amino acids into peptides is a powerful approach for generating structurally defined peptides as conformational probes and bioactive agents. The ability to site-specifically introduce constrained amino acids into large polypeptide chains would provide a similar opportunity to probe the flexibility, conformation, folding and stability of proteins. To this end, we have examined the competence of the Escherichia coli protein biosynthetic machinery to incorporate a number of these unnatural amino acids into the 164 residue protein T4 lysozyme (T4L). Results clearly demonstrate that the protein biosynthetic machinery can accommodate a wide variety of conformationally constrained amino acids. The expansion of structural motifs that can be biosynthetically incorporated into proteins to include a large number of conformationally constrained amino acids significantly increases the power of mutagenesis methods as probes of protein structure and function and provides additional insights into the steric requirements of the translational machinery. 13 refs., 2 figs.

  3. Animal models of human amino acid responses.

    PubMed

    Baker, David H

    2004-06-01

    The principal differences between experimental animals and humans with regard to amino acid responses are 1) growing animals partition most of their amino acid intake to protein accretion, whereas growing children partition most of their intake to maintenance; 2) invasive assessment procedures are common in animals but very limited in humans; and 3) humans can describe how they feel in response to amino acid levels or balances, whereas animals cannot. New (pharmacologic) uses of amino acids have been and are being discovered (e.g., cysteine, arginine, leucine, glutamine), and this makes it imperative that tolerance limits be established. Work with pigs suggests that excessive intake of methionine and tryptophan present the biggest problems, whereas excessive intake of threonine, glutamate, and the branched-chain amino acids seems to be well tolerated. PMID:15173445

  4. Amino acids in the Martian meteorite Nakhla

    PubMed Central

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

    1999-01-01

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

  5. Amino acids in the Martian meteorite Nakhla

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  6. Genetics of Amino Acid Taste and Appetite.

    PubMed

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

    2016-07-01

    The consumption of amino acids by animals is controlled by both oral and postoral mechanisms. We used a genetic approach to investigate these mechanisms. Our studies have shown that inbred mouse strains differ in voluntary amino acid consumption, and these differences depend on sensory and nutritive properties of amino acids. Like humans, mice perceive some amino acids as having a sweet (sucrose-like) taste and others as having an umami (glutamate-like) taste. Mouse strain differences in the consumption of some sweet-tasting amino acids (d-phenylalanine, d-tryptophan, and l-proline) are associated with polymorphisms of a taste receptor, type 1, member 3 gene (Tas1r3), and involve differential peripheral taste responsiveness. Strain differences in the consumption of some other sweet-tasting amino acids (glycine, l-alanine, l-glutamine, and l-threonine) do not depend on Tas1r3 polymorphisms and so must be due to allelic variation in other, as yet unknown, genes involved in sweet taste. Strain differences in the consumption of l-glutamate may depend on postingestive rather than taste mechanisms. Thus, genes and physiologic mechanisms responsible for strain differences in the consumption of each amino acid depend on the nature of its taste and postingestive properties. Overall, mouse strain differences in amino acid taste and appetite have a complex genetic architecture. In addition to the Tas1r3 gene, these differences depend on other genes likely involved in determining the taste and postingestive effects of amino acids. The identification of these genes may lead to the discovery of novel mechanisms that regulate amino acid taste and appetite. PMID:27422518

  7. Exogenous amino acids as fuel in shock.

    PubMed

    Daniel, A M; Kapadia, B; MacLean, L D

    1982-01-01

    It has been suggested that in shock branched-chain amino acids are preferentially oxidized resulting in continued proteolysis and stimulated gluconeogenesis. To determine if exogenous amino acids could be used as fuel in shock, dogs rendered hypotensive by controlled cardiac tamponade and normotensive controls were infused with amino acid mixtures and individual amino acids. When Nephramine, a mixture rich in branched-chain amino acids, was infused, plasma alpha-amino nitrogen levels rose but urea output did not increase in either the control state or in shock, suggesting that these amino acids were not rapidly deaminated to serve as fuels. Travasol, which in addition contained large amounts of alanine and glycine, tripled urea output in the controls and doubled it in shock. The limit of urea production was reached in both groups at 35 mumoles urea/minute/kg. In the Travasol-infused animals plasma alpha-amino nitrogen levels were maintained in normotension but rose sharply in shock. When glycine alone was infused into five dogs in shock urea production rate was 30.6 + 2.1 mumoles/minute/kg; with alanine the same value was 22.5 + 2.2 mumoles/minute/kg. In both cases plasma alpha-amino nitrogen levels were high, suggesting that transport of these amino acids into the cell was slow in shock. In four dogs in shock glycine-14C was added to the glycine infusate as a tracer. At radioactive equilibrium 28% of the label infused appeared in CO2; another 22% appeared in glucose. It is concluded that of all the amino acids tested only glycine and alanine are deaminated rapidly enough to serve as exogenous fuels in shock. PMID:6814205

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

    PubMed

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

    2016-10-15

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

  9. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-09-15

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

  10. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, Mark M.; Shoup, Timothy

    1998-10-06

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

  11. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-09-15

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

  12. Amino acid analogs for tumor imaging

    DOEpatents

    Goodman, M.M.; Shoup, T.

    1998-10-06

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

  13. Amino acid transporters: roles in amino acid sensing and signalling in animal cells.

    PubMed Central

    Hyde, Russell; Taylor, Peter M; Hundal, Harinder S

    2003-01-01

    Amino acid availability regulates cellular physiology by modulating gene expression and signal transduction pathways. However, although the signalling intermediates between nutrient availability and altered gene expression have become increasingly well documented, how eukaryotic cells sense the presence of either a nutritionally rich or deprived medium is still uncertain. From recent studies it appears that the intracellular amino acid pool size is particularly important in regulating translational effectors, thus, regulated transport of amino acids across the plasma membrane represents a means by which the cellular response to amino acids could be controlled. Furthermore, evidence from studies with transportable amino acid analogues has demonstrated that flux through amino acid transporters may act as an initiator of nutritional signalling. This evidence, coupled with the substrate selectivity and sensitivity to nutrient availability classically associated with amino acid transporters, plus the recent discovery of transporter-associated signalling proteins, demonstrates a potential role for nutrient transporters as initiators of cellular nutrient signalling. Here, we review the evidence supporting the idea that distinct amino acid "receptors" function to detect and transmit certain nutrient stimuli in higher eukaryotes. In particular, we focus on the role that amino acid transporters may play in the sensing of amino acid levels, both directly as initiators of nutrient signalling and indirectly as regulators of external amino acid access to intracellular receptor/signalling mechanisms. PMID:12879880

  14. The immunogenicity of dinitrophenyl amino acids.

    PubMed

    Frey, J R; de Weck, A L; Geleick, H; Lergier, W

    1969-11-01

    Numerous dinitrophenyl amino acid preparations injected intradermally induced contact hypersensitivity to dinitrochlorobenzene, delayed type skin reactions to DNP-amino acids, and anti-DNP antibodies in guinea pigs. Some DNP-amino adds induced precipitating anti-DNP antibodies in rabbits as well. Some of the DNP-ammo acids studied were regularly immunogenic, possible immunogenic impurities having been excluded by extensive purification procedures. Others were either constantly nonimmunogenic or irregularly immunogenic, e.g., their immunogenicity varying from one preparation lot to another. By means of extensive chemical analyses and the establishment of dose-response curves, we were able to demonstrate in most cases that the immunogenicity was not due to contamination with unreacted dinitrofluorobenzene or other DNP derivatives, to photodecomposition or other degradation products, or to DNP-protein contaminants. Nevertheless, the irregular immunogenicity of several DNP-amino acid preparations can only be explained by a highly immunogenic impurity (or impurities) which we were unable to detect analytically. The regular immunogenicity of some other DNP-amino acids (e.g. di-DNP-L-histidine) appears to be based on a "transconjugation" phenomenon, the DNP group being able to split off from its amino acid carrier and to conjugate secondarily with proteins in vivo and in vitro. Accordingly, the interpretation of some recent data concerning the immunogenicity of low molecular weight hapten-amino acids may have to be reevaluated. PMID:4981513

  15. Amino acids in human and animal nutrition.

    PubMed

    Karau, Andreas; Grayson, Ian

    2014-01-01

    Amino acids are key components of human and animal nutrition, both as part of a protein-containing diet, and as supplemented individual products. In the last 10 years there has been a marked move away from the extraction of amino acids from natural products, which has been replaced by efficient fermentation processes using nonanimal carbon sources. Today several amino acids are produced in fermentation plants with capacities of more than 100,000 tonnes to serve the requirements of animal feed and human nutrition. The main fermentative amino acids for animal nutrition are L-lysine, L-threonine, and L-tryptophan. DL-Methionine continues to be manufactured for animal feed use principally by chemical synthesis, and a pharmaceutical grade is manufactured by enzymatic resolution. Amino acids play an important role in medical nutrition, particularly in parenteral nutrition, where there are high purity requirements for infusion grade products. Amino acids are also appearing more often in dietary supplements, initially for performance athletes, but increasingly for the general population. As the understanding of the effects of the individual amino acids on the human metabolism is deepened, more specialized product mixtures are being offered to improve athletic performance and for body-building. PMID:24676880

  16. Distribution of Amino Acids in Lunar Regolith

    NASA Technical Reports Server (NTRS)

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

    2014-01-01

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

  17. Amino Acid Stability in the Early Oceans

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

  18. Amino Acid Degradation after Meteoritic Impact Simulation

    NASA Technical Reports Server (NTRS)

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

    2008-01-01

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

  19. Amino acid analysis for pharmacopoeial purposes.

    PubMed

    Wahl, Oliver; Holzgrabe, Ulrike

    2016-07-01

    The impurity profile of amino acids depends strongly on the production process. Since there are many different production methods (e.g. fermentation, protein hydrolysis or chemical synthesis) universal, state of the art methods are required to determine the impurity profile of amino acids produced by all relevant competitors. At the moment TLC tests provided by the Ph. Eur. are being replaced by a very specific amino acid analysis procedure possibly missing out on currently unknown process related impurities. Production methods and possible impurities as well as separation and detection methods suitable for said impurities are subject to this review. PMID:27154660

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

    MedlinePlus

    ... aromatic l-amino acid decarboxylase deficiency aromatic l-amino acid decarboxylase deficiency Enable Javascript to view the expand/ ... PDF Open All Close All Description Aromatic l-amino acid decarboxylase (AADC) deficiency is an inherited disorder that ...

  1. Rag GTPase in amino acid signaling.

    PubMed

    Kim, Joungmok; Kim, Eunjung

    2016-04-01

    Rag small GTPases were identified as the sixth subfamily of Ras-related GTPases. Compelling evidence suggests that Rag heterodimer (RagA/B and RagC/D) plays an important role in amino acid signaling toward mechanistic target of rapamycin complex 1 (mTORC1), which is a central player in the control of cell growth in response to a variety of environmental cues, including growth factors, cellular energy/oxygen status, and amino acids. Upon amino acid stimulation, active Rag heterodimer (RagA/B(GTP)-RagC/D(GDP)) recruits mTORC1 to the lysosomal membrane where Rheb resides. In this review, we provide a current understanding on the amino acid-regulated cell growth control via Rag-mTORC1 with recently identified key players, including Ragulator, v-ATPase, and GATOR complexes. Moreover, the functions of Rag in physiological systems and in autophagy are discussed. PMID:26781224

  2. D-amino acids trigger biofilm disassembly.

    PubMed

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

    2010-04-30

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

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

    PubMed Central

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

    2014-01-01

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

  4. Genetically encoded fluorescent coumarin amino acids

    DOEpatents

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

    2010-10-05

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

  5. Genetically encoded fluorescent coumarin amino acids

    DOEpatents

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

    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.

  6. Nonprotein Amino Acids from Spark Discharges and Their Comparison with the Murchison Meteorite Amino Acids

    PubMed Central

    Wolman, Yecheskel; Haverland, William J.; Miller, Stanley L.

    1972-01-01

    All the nonprotein amino acids found in the Murchison meteorite are products of the action of electric discharge on a mixture of methane, nitrogen, and water with traces of ammonia. These amino acids include α-amino-n-butyric acid, α-aminoisobutyric acid, norvaline, isovaline, pipecolic acid, β-alanine, β-amino-n-butyric acid, β-aminoisobutyric acid, γ-aminobutyric acid, sarcosine, N-ethylglycine, and N-methylalanine. In addition, norleucine, alloisoleucine, N-propylglycine, N-isopropylglycine, N-methyl-β-alanine, N-ethyl-β-alanine α,β-diaminopropionic acid, isoserine, α,γ-diaminobutyric acid, and α-hydroxy-γ-aminobutyric acid are produced by the electric discharge, but have not been found in the meteorite. PMID:16591973

  7. Nonprotein amino acids from spark discharges and their comparison with the murchison meteorite amino acids.

    PubMed

    Wolman, Y; Haverland, W J; Miller, S L

    1972-04-01

    All the nonprotein amino acids found in the Murchison meteorite are products of the action of electric discharge on a mixture of methane, nitrogen, and water with traces of ammonia. These amino acids include alpha-amino-n-butyric acid, alpha-aminoisobutyric acid, norvaline, isovaline, pipecolic acid, beta-alanine, beta-amino-n-butyric acid, beta-aminoisobutyric acid, gamma-aminobutyric acid, sarcosine, N-ethylglycine, and N-methylalanine. In addition, norleucine, alloisoleucine, N-propylglycine, N-isopropylglycine, N-methyl-beta-alanine, N-ethyl-beta-alanine alpha,beta-diaminopropionic acid, isoserine, alpha,gamma-diaminobutyric acid, and alpha-hydroxy-gamma-aminobutyric acid are produced by the electric discharge, but have not been found in the meteorite. PMID:16591973

  8. Amino acid composition and amino acid-metabolic network in supragingival plaque.

    PubMed

    Washio, Jumpei; Ogawa, Tamaki; Suzuki, Keisuke; Tsukiboshi, Yosuke; Watanabe, Motohiro; Takahashi, Nobuhiro

    2016-01-01

    Dental plaque metabolizes both carbohydrates and amino acids. The former can be degraded to acids mainly, while the latter can be degraded to various metabolites, including ammonia, acids and amines, and associated with acid-neutralization, oral malodor and tissue inflammation. However, amino acid metabolism in dental plaque is still unclear. This study aimed to elucidate what kinds of amino acids are available as metabolic substrates and how the amino acids are metabolized in supragingival plaque, by a metabolome analysis. Amino acids and the related metabolites in supragingival plaque were extracted and quantified comprehensively by CE-TOFMS. Plaque samples were also incubated with amino acids, and the amounts of ammonia and amino acid-related metabolites were measured. The concentration of glutamate was the highest in supragingival plaque, while the ammonia-production was the highest from glutamine. The obtained metabolome profile revealed that amino acids are degraded through various metabolic pathways, including deamination, decarboxylation and transamination and that these metabolic systems may link each other, as well as with carbohydrate metabolic pathways in dental plaque ecosystem. Moreover, glutamine and glutamate might be the main source of ammonia production, as well as arginine, and contribute to pH-homeostasis and counteraction to acid-induced demineralization in supragingival plaque. PMID:27545001

  9. Amino acids in modern and fossil woods

    NASA Technical Reports Server (NTRS)

    Lee, C.; Bada, J. L.; Peterson, E.

    1976-01-01

    The amino acid composition and the extent of racemization in several modern and fossil woods are reported. The method of analysis is described, and data are presented on the total amino acid concentration, the amino acid ratios, and the enantiomeric ratios in each sample. It is found that the amino acid concentration per gram of dry wood decreases with age of the sample, that the extent of racemization increases with increasing age, and that the amounts of aspartic acid, threonine, and serine decrease relative to valine with increasing age. The relative racemization rates of amino acids in wood, bone, and aqueous solution are compared, and it is shown that racemization in wood is much slower than in bone or aqueous solution. Racemization results for woods from the Kalambo Falls area of Zambia are used to calculate a minimum age of 110,000 years for the transition between the Sangoan and Acheulian industries at that site. This result is shown to be consistent with numerous radiometric dates for older Acheulian sites in Africa and to compare well with geologically inferred dates for the beginning of the Eemian and the end of the Acheulian industry in southern Africa.

  10. Amino acid survival in large cometary impacts

    NASA Astrophysics Data System (ADS)

    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.

  11. Amino acid isotopic analysis in agricultural systems

    Technology Transfer Automated Retrieval System (TEKTRAN)

    A relatively new approach to stable isotopic analysis—referred to as compound-specific isotopic analysis (CSIA)—has emerged, centering on the measurement of 15N:14N ratios in amino acids (glutamic acid and phenylalanine). CSIA has recently been used to generate trophic position estimates among anima...

  12. Amino acids in the Yamato carbonaceous chrondrite from Antarctica

    NASA Technical Reports Server (NTRS)

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

    1979-01-01

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

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

    NASA Technical Reports Server (NTRS)

    Shapshak, P.; Okaji, M.

    1972-01-01

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

  14. Amino Acids Profiles in Biological Media

    SciTech Connect

    Iordache, A.; Horj, E.; Morar, S.; Cozar, O.; Culea, M.; Ani, A. R.; Mesaros, C.

    2010-08-04

    An accurate analytical method was developed to determine amino acids in some biological specimens by GC/MS technique. Stable isotopes provide useful tools for a variety of studies, offering ideal internal standards in quantitative information. Isotopic dilution gas chromatography--mass spectrometry (ID-GC/MS) is the techniques used for quantitative analysis of compounds labeled with stable isotopes. A Trace DSQ Thermo Finnigan quadrupole mass spectrometer coupled with a Trace GC was used. Amino acids were separated on a Rtx-5 MS capillary column, 30 mx0.25 mm, 0.25 {mu}m film thickness, using a temperature program from 50 deg. C, 1 min, 6 deg. C/min at 100 deg. C, 4 deg. C/min at 200 deg. C, 20 deg. C/min at 300 deg. C, (3 min). The transfer line temperature was 250 deg. C, the injector temperature 200 deg. C and ion source temperature 250 deg. C; splitter: 10:1. Electron energy was 70 eV and emission current, 100 {mu}A. The amino acids were purified on a Dowex 50W-W8 exchange resin and were derivatized in a procedure following two steps to obtain trifluoroacetyl butyl esters. The identification of amino acids was obtained by using NIST library but also by using amino acid standards.

  15. Distinguishing Proteins From Arbitrary Amino Acid Sequences

    PubMed Central

    Yau, Stephen S.-T.; Mao, Wei-Guang; Benson, Max; He, Rong Lucy

    2015-01-01

    What kinds of amino acid sequences could possibly be protein sequences? From all existing databases that we can find, known proteins are only a small fraction of all possible combinations of amino acids. Beginning with Sanger's first detailed determination of a protein sequence in 1952, previous studies have focused on describing the structure of existing protein sequences in order to construct the protein universe. No one, however, has developed a criteria for determining whether an arbitrary amino acid sequence can be a protein. Here we show that when the collection of arbitrary amino acid sequences is viewed in an appropriate geometric context, the protein sequences cluster together. This leads to a new computational test, described here, that has proved to be remarkably accurate at determining whether an arbitrary amino acid sequence can be a protein. Even more, if the results of this test indicate that the sequence can be a protein, and it is indeed a protein sequence, then its identity as a protein sequence is uniquely defined. We anticipate our computational test will be useful for those who are attempting to complete the job of discovering all proteins, or constructing the protein universe. PMID:25609314

  16. Amino Acids Profiles in Biological Media

    NASA Astrophysics Data System (ADS)

    Iordache, A.; Horj, E.; Ani, A. R.; Mesaros, C.; Morar, S.; Cozar, O.; Culea, M.

    2010-08-01

    An accurate analytical method was developed to determine amino acids in some biological specimens by GC/MS technique. Stable isotopes provide useful tools for a variety of studies, offering ideal internal standards in quantitative information. Isotopic dilution gas chromatography—mass spectrometry (ID-GC/MS) is the techniques used for quantitative analysis of compounds labeled with stable isotopes. A Trace DSQ Thermo Finnigan quadrupole mass spectrometer coupled with a Trace GC was used. Amino acids were separated on a Rtx-5 MS capillary column, 30 m×0.25 mm, 0.25 μm film thickness, using a temperature program from 50 °C, 1 min, 6 °C/min at 100 °C, 4 °C/min at 200 °C, 20 °C/min at 300 °C, (3 min). The transfer line temperature was 250 °C, the injector temperature 200 °C and ion source temperature 250 °C; splitter: 10:1. Electron energy was 70 eV and emission current, 100 μA. The amino acids were purified on a Dowex 50W-W8 exchange resin and were derivatized in a procedure following two steps to obtain trifluoroacetyl butyl esters. The identification of amino acids was obtained by using NIST library but also by using amino acid standards.

  17. Environmental roles of microbial amino acid racemases.

    PubMed

    Hernández, Sara B; Cava, Felipe

    2016-06-01

    Enzymes catalysing the stereo-chemical inter-conversion of amino acids are known as amino acid racemases. In bacteria, these enzymes are fundamental to synthesize the D-Ala and D-Glu that are critical components of the peptidoglycan. In addition to this structural function in cell wall assembly, D-amino acids produced by microbial amino acid racemases have been described as relevant constituents in other prokaryotic structures (e.g. capsule, non-ribosomal peptides) and have been associated to growth fitness and to processes such as biofilm development, spore germination and signalling. The recent discovery of broad spectrum racemases able to produce and release several D-amino acids to the environment suggests that these enzymes might have a great impact in microbial ecology. Consequently, new data on the biochemistry and regulation of racemases is key to understand the biological significance of D-enantiomers in nature, in particular their effect on microbial social networks. This review summarizes current knowledge on the environmental roles of bacterial racemases with an emphasis on the potential roles of the new broad spectrum enzymes in natural environments. PMID:26419727

  18. The amino acid sequence of chymopapain from Carica papaya.

    PubMed Central

    Watson, D C; Yaguchi, M; Lynn, K R

    1990-01-01

    Chymopapain is a polypeptide of 218 amino acid residues. It has considerable structural similarity with papain and papaya proteinase omega, including conservation of the catalytic site and of the disulphide bonding. Chymopapain is like papaya proteinase omega in carrying four extra residues between papain positions 168 and 169, but differs from both papaya proteinases in the composition of its S2 subsite, as well as in having a second thiol group, Cys-117. Some evidence for the amino acid sequence of chymopapain has been deposited as Supplementary Publication SUP 50153 (12 pages) at the British Library Document Supply Centre, Boston Spa., Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1990) 265, 5. The information comprises Supplement Tables 1-4, which contain, in order, amino acid compositions of peptides from tryptic, peptic, CNBr and mild acid cleavages, Supplement Fig. 1, showing re-fractionation of selected peaks from Fig. 2 of the main paper. Supplement Fig. 2, showing cation-exchange chromatography of the earliest-eluted peak of Fig. 3 of the main paper, Supplement Fig. 3, showing reverse-phase h.p.l.c. of the later-eluted peak from Fig. 3 of the main paper, and Supplement Fig. 4, showing the separation of peptides after mild acid hydrolysis of CNBr-cleavage fragment CB3. PMID:2106878

  19. The amino acid sequence of chymopapain from Carica papaya.

    PubMed

    Watson, D C; Yaguchi, M; Lynn, K R

    1990-02-15

    Chymopapain is a polypeptide of 218 amino acid residues. It has considerable structural similarity with papain and papaya proteinase omega, including conservation of the catalytic site and of the disulphide bonding. Chymopapain is like papaya proteinase omega in carrying four extra residues between papain positions 168 and 169, but differs from both papaya proteinases in the composition of its S2 subsite, as well as in having a second thiol group, Cys-117. Some evidence for the amino acid sequence of chymopapain has been deposited as Supplementary Publication SUP 50153 (12 pages) at the British Library Document Supply Centre, Boston Spa., Wetherby, West Yorkshire LS23 7BQ, U.K., from whom copies may be obtained on the terms indicated in Biochem. J. (1990) 265, 5. The information comprises Supplement Tables 1-4, which contain, in order, amino acid compositions of peptides from tryptic, peptic, CNBr and mild acid cleavages, Supplement Fig. 1, showing re-fractionation of selected peaks from Fig. 2 of the main paper. Supplement Fig. 2, showing cation-exchange chromatography of the earliest-eluted peak of Fig. 3 of the main paper, Supplement Fig. 3, showing reverse-phase h.p.l.c. of the later-eluted peak from Fig. 3 of the main paper, and Supplement Fig. 4, showing the separation of peptides after mild acid hydrolysis of CNBr-cleavage fragment CB3. PMID:2106878

  20. Amino acids of the Murchison meteorite. III - Seven carbon acyclic primary alpha-amino alkanoic acids

    NASA Technical Reports Server (NTRS)

    Cronin, John R.; Pizzarello, Sandra

    1986-01-01

    All of the eighteen possible seven-carbon acyclic primary alpha-amino alkanoic acids have been positively identified in a hot-water extract of the Murchison meteorite by the combined use of gas chromatography-mass spectrometry, ion exchange chromatography and reversed-phase chromatography. None of these amino acids has previously been found in meteorites or in any other natural material. They range in concentration from less than or equal to 0.5 to 5.3 nmol/g. Configuration assignments were made for 2-amino-3,4-dimethylpentanoic acid and allo-2-amino-3,4-dimethylpentanoic acid and the diasteromer ratio was determined. Fifty-five amino acids have now been positively identified in the Murchison meteorite, 36 of which are unknown in terrestrial materials. This unique suite of amino acids is characterized by the occurrence of all structural isomers within the two major classes of amino acids represented, by the predominance of branched chain isomers, and by an exponential decline in amount with increasing carbon chain length within homologous series. These characteristics of the Murchison amino acids are suggestive of synthesis before incorporation into a parent body.

  1. Economic aspects of amino acids production.

    PubMed

    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

  2. Temperature dependence of amino acid hydrophobicities

    PubMed Central

    Wolfenden, Richard; Lewis, Charles A.; Yuan, Yang; Carter, Charles W.

    2015-01-01

    The hydrophobicities of the 20 common amino acids are reflected in their tendencies to appear in interior positions in globular proteins and in deeply buried positions of membrane proteins. To determine whether these relationships might also have been valid in the warm surroundings where life may have originated, we examined the effect of temperature on the hydrophobicities of the amino acids as measured by the equilibrium constants for transfer of their side-chains from neutral solution to cyclohexane (Kw>c). The hydrophobicities of most amino acids were found to increase with increasing temperature. Because that effect is more pronounced for the more polar amino acids, the numerical range of Kw>c values decreases with increasing temperature. There are also modest changes in the ordering of the more polar amino acids. However, those changes are such that they would have tended to minimize the otherwise disruptive effects of a changing thermal environment on the evolution of protein structure. Earlier, the genetic code was found to be organized in such a way that—with a single exception (threonine)—the side-chain dichotomy polar/nonpolar matches the nucleic acid base dichotomy purine/pyrimidine at the second position of each coding triplet at 25 °C. That dichotomy is preserved at 100 °C. The accessible surface areas of amino acid side-chains in folded proteins are moderately correlated with hydrophobicity, but when free energies of vapor-to-cyclohexane transfer (corresponding to size) are taken into consideration, a closer relationship becomes apparent. PMID:26034278

  3. L-amino acid oxidases with specificity for basic L-amino acids in cyanobacteria.

    PubMed

    Gau, Achim E; Heindl, Achim; Nodop, Anke; Kahmann, Uwe; Pistorius, Elfriede K

    2007-01-01

    The two closely related fresh water cyanobacteria Synechococcus elongatus PCC 6301 and Synechococcus elongatus PCC 7942 have previously been shown to constitutively express a FAD-containing L-amino acid oxidase with high specificity for basic L-amino acids (L-arginine being the best substrate). In this paper we show that such an enzyme is also present in the fresh water cyanobacterium Synechococcus cedrorum PCC 6908. In addition, an improved evaluation of the nucleotide/amino acid sequence of the L-amino acid oxidase of Synechococcus elongatus PCC 6301 (encoded by the aoxA gene) with respect to the FAD-binding site and a translocation pathway signal sequence will be given. Moreover, the genome sequences of 24 cyanobacteria will be evaluated for the occurrence of an aoxA-similar gene. In the evaluated cyanobacteria 15 genes encoding an L-amino acid oxidase-similar protein will be found. PMID:17542496

  4. Amino acid precursors in lunar samples.

    NASA Technical Reports Server (NTRS)

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

    1972-01-01

    The use of hot water to extract lunar samples, followed by the hydrolysis of the aqueous extract, appears to be the method of choice for identification and quantitation of amino acid precursors in extraterrestrial sources. The net inferences from the analyses to date are (1) that amino acid precursors are verifiably present in lunar dust, and (2) that they are quite certainly not the consequence of contamination by terrestrial organisms, including man. It is suggested that prebiotic evolutionary pathways such as have been traversed on the earth were terminated on the moon for lack of sufficient water. Although some or all of the amino acid precursors may be indigenous, the low level observed suggests that they may also result from onfall of organic compounds from interstellar matter, comets, tails, solar wind, or meteorites.

  5. Antibody conjugates with unnatural amino acids.

    PubMed

    Hallam, Trevor J; Wold, Erik; Wahl, Alan; Smider, Vaughn V

    2015-06-01

    Antibody conjugates are important in many areas of medicine and biological research, and antibody-drug conjugates (ADCs) are becoming an important next generation class of therapeutics for cancer treatment. Early conjugation technologies relied upon random conjugation to multiple amino acid side chains, resulting in heterogeneous mixtures of labeled antibody. Recent studies, however, strongly support the notion that site-specific conjugation produces a homogeneous population of antibody conjugates with improved pharmacologic properties over randomly coupled molecules. Genetically incorporated unnatural amino acids (uAAs) allow unique orthogonal coupling strategies compared to those used for the 20 naturally occurring amino acids. Thus, uAAs provide a novel paradigm for creation of next generation ADCs. Additionally, uAA-based site-specific conjugation could also empower creation of additional multifunctional conjugates important as biopharmaceuticals, diagnostics, or reagents. PMID:25898256

  6. Terahertz broadband spectroscopic investigations of amino acid

    NASA Astrophysics Data System (ADS)

    Zhu, De-chong; Zhang, Liang-liang; Zhong, Hua; Zhang, Cun-lin

    2011-08-01

    We present an experimental terahertz (THz) spectroscopic investigation of amino acid using an air-breakdown-coherent detection (ABCD) system. The strong and ultra-broadband (0.1 to 10THz) terahertz radiations generated by two-color laser induced air plasma and measured by coherent heterodyne detection. The broadband THz reflection spectra of L-Lysine (C6H14N2O2) and L-Arginine (C6H14N2O2) are obtained. To solve the phase-retrieval problem in RTDS, the absorption signatures of the materials are extracted directly from the first derivative of the relative reflectance with respect to frequency. The absorption features of the two amino acids are characterized in the 0.5~6 THz region. It is found that both the two amino acids have an absorption peak at 1.10 THz.

  7. Probing protein stability with unnatural amino acids

    SciTech Connect

    Mendel, D.; Ellman, J.A.; Zhiyuh Chang; Veenstra, D.L.; Kollman, P.A.; Schultz, P.G. )

    1992-06-26

    Unnatural amino acid mutagenesis, in combination with molecular modeling and simulation techniques, was used to probe the effect of side chain structure on protein stability. Specific replacements at position 133 in T4 lysozyme included (1) leucine (wt), norvaline, ethylglycine, and alanine to measure the cost of stepwise removal of methyl groups from the hydrophobic core, (2) norvaline and O-methyl serine to evaluate the effects of side chain solvation, and (3) leucine, S,S-2-amino-4-methylhexanoic acid, and S-2-amino-3-cyclopentylpropanoic acid to measure the influence of packing density and side chain conformational entropy on protein stability. All of these factors (hydrophobicity, packing, conformational entropy, and cavity formation) significantly influence protein stability and must be considered when analyzing any structural change to proteins.

  8. Cometary Amino Acids from the STARDUST Mission

    NASA Technical Reports Server (NTRS)

    Cook, Jamie Elsila

    2009-01-01

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

  9. Amino-Acid Sequence of Porcine Pepsin

    PubMed Central

    Tang, J.; Sepulveda, P.; Marciniszyn, J.; Chen, K. C. S.; Huang, W-Y.; Tao, N.; Liu, D.; Lanier, J. P.

    1973-01-01

    As the culmination of several years of experiments, we propose a complete amino-acid sequence for porcine pepsin, an enzyme containing 327 amino-acid residues in a single polypeptide chain. In the sequence determination, the enzyme was treated with cyanogen bromide. Five resulting fragments were purified. The amino-acid sequence of four of the fragments accounted for 290 residues. Because the structure of a 37-residue carboxyl-terminal fragment was already known, it was not studied. The alignment of these fragments was determined from the sequence of methionyl-peptides we had previously reported. We also discovered the locations of activesite aspartyl residues, as well as the pairing of the three disulfide bridges. A minor component of commercial crystalline pepsin was found to contain two extra amino-acid residues, Ala-Leu-, at the amino-terminus of the molecule. This minor component was apparently derived from a different site of cleavage during the activation of porcine pepsinogen. PMID:4587252

  10. Biosynthesis of the Aromatic Amino Acids.

    PubMed

    Pittard, James; Yang, Ji

    2008-09-01

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

  11. Protein and amino Acid supplementation in athletes.

    PubMed

    Armsey, Thomas D; Grime, Todd E

    2002-08-01

    Amino acid supplementation is practiced by numerous individuals with the hope of increasing muscle mass and function by increasing available proteins. Theoretically, this makes a great deal of sense; the scientific facts, however, fail to conclusively prove that ingesting more than the recommended dietary allowance of protein has any effect on otherwise healthy adults. Athletes may be the exception to this rule. This review examines the most current literature pertaining to amino acid supplementation, and reports on the potential benefits and risks of this common practice. PMID:12831703

  12. Apical transporters for neutral amino acids: physiology and pathophysiology.

    PubMed

    Bröer, Stefan

    2008-04-01

    Absorption of amino acids in kidney and intestine involves a variety of transporters for different groups of amino acids. This is illustrated by inherited disorders of amino acid absorption, such as Hartnup disorder, cystinuria, iminoglycinuria, dicarboxylic aminoaciduria, and lysinuric protein intolerance, affecting separate groups of amino acids. Recent advances in the molecular identification of apical neutral amino acid transporters has shed a light on the molecular basis of Hartnup disorder and iminoglycinuria. PMID:18400692

  13. Improving impurities clearance by amino acids addition to buffer solutions for chromatographic purifications of monoclonal antibodies.

    PubMed

    Ishihara, Takashi; Hosono, Mareto

    2015-07-15

    The performance of amino acids in Protein A affinity chromatography, anion exchange chromatography and cation exchange chromatography for monoclonal antibody purification was investigated. Glycine, threonine, arginine, glutamate, and histidine were used as buffer components in the equilibration, washing, and elution steps of these chromatographies. Improved clearance of impurity, high molecular weight species (HMW) and host cell proteins (HCP) was observed in the purification processes when using the amino acids as base-buffer constituents, additives or eluents compared with that of buffers without these amino acids. In addition, we designed a buffer system in which the mobile phases were composed of only a single amino acid, histidine, and applied it to the above three chromatographies. Effective HMW and HCP clearance was also obtained in this manner. These results suggest that amino acids may enhance impurity clearance during the purification of monoclonal antibodies. PMID:26057847

  14. Polymerization of amino acids containing nucleotide bases

    NASA Technical Reports Server (NTRS)

    Ben Cheikh, Azzouz; Orgel, Leslie E.

    1990-01-01

    The nucleoamino acids 1-(3'-amino,3'-carboxypropyl)uracil (3) and 9-(3'-amino,3'-carboxypropyl)adenine (4) have been prepared as (L)-en-antiomers and as racemic mixtures. When 3 or 4 is suspended in water and treated with N,N'-carbon-yldiimidazole, peptides are formed in good yield. The products formed from the (L)-enantiomers are hydrolyzed to the monomeric amino acids by pronase. Attempts to improve the efficiency of these oligomerizations by including a polyuridylate template in the reaction mixture were not successful. Similarly, oligomers derived from the (L)-enantiomer of 3 did not act as templates to facilitate the oligomerization of 4.

  15. The Exchangeability of Amino Acids in Proteins

    PubMed Central

    Yampolsky, Lev Y.; Stoltzfus, Arlin

    2005-01-01

    The comparative analysis of protein sequences depends crucially on measures of amino acid similarity or distance. Many such measures exist, yet it is not known how well these measures reflect the operational exchangeability of amino acids in proteins, since most are derived by methods that confound a variety of effects, including effects of mutation. In pursuit of a pure measure of exchangeability, we present (1) a compilation of data on the effects of 9671 amino acid exchanges engineered and assayed in a set of 12 proteins; (2) a statistical procedure to combine results from diverse assays of exchange effects; (3) a matrix of “experimental exchangeability” values EXij derived from applying this procedure to the compiled data; and (4) a set of three tests designed to evaluate the power of an exchangeability measure to (i) predict the effects of amino acid exchanges in the laboratory, (ii) account for the disease-causing potential of missense mutations in the human population, and (iii) model the probability of fixation of missense mutations in evolution. EX not only captures useful information on exchangeability while remaining free of other effects, but also outperforms all measures tested except for the best-performing alignment scoring matrix, which is comparable in performance. PMID:15944362

  16. 21 CFR 172.320 - Amino acids.

    Code of Federal Regulations, 2010 CFR

    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 §...

  17. Intestinal metabolism of sulfur amino acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    The gastrointestinal tract (GIT) is a metabolically significant site of sulfur amino acid (SAA) metabolism in the body and metabolizes approx. 20% of the dietary methionine intake that is mainly transmethylated to homocysteine and transsulfurated to cysteine. The GIT accounts for approx. 25% of the ...

  18. [Plasma amino acid concentrations in aggressive dogs].

    PubMed

    Juhr, Norbert-Christian; Brand, Ulrike; Riedel, Eberhard

    2005-01-01

    Following the hypothesis that metabolic screens may be useful tools in the diagnosis of canine aggression we have investigated the blood plasma amino acid levels of dogs which have been found aggressive (N = 10) against dogs or men in comparison to non-aggressive dogs (N = 10). In summary, the aggressive dogs showed elevated plasma concentrations of the neurophysiological active aromatic amino acids tryptophan (46/171 micromol/l, p < 0,001), tyrosine (38/67 micromol/l, p < 0.01) and histidine (74/91 micromol/l, p < 0.01) and lower lysine concentrations (175/151 micromol/l, p < 0.05), which seems to point to a stress situation of these dogs. The nitrogen metabolism is impaired in the urea-cycle in the conversion of ornithine (17/34 micromol/l, p < 0.01) to citrulline (64/47 micromol/l). Higher levels of branched chain amino acids, especially leucine (122/150 micromol/l, p < 0.01), mainly metabolized in muscles, and isoleucin (60/71 micromol/l, p < 0.05) show a high energy potential. The acidose-stimulator methionine (48/78 micromol/l, p < 0.01) proved elevated. The results show that the changed behavior in the aggressive dogs is also reflected in their free amino acid plasma concentrations, independent of the question whether these data are the cause or the result of the aggressivity. PMID:15803756

  19. Amino acid composition of humic substances in tundra soils

    NASA Astrophysics Data System (ADS)

    Vasilevich, R. S.; Beznosikov, V. A.

    2015-06-01

    Peripheral amino acid fragments of humic and fulvic acid molecules from tundra soils have been identified and quantified. A significant weight fraction of amino acids has been found in humic acid preparations, which exceeds their content in fulvic acids. Features of the amino acid composition of humic substances along the soil profile and depending on the degree of hydromorphism and the proportions of different (neutral, basic, acidic, cyclic) groups in amino acids have been revealed. The molar ratio between the hydroxy and heterocyclic amino acids reflects the degree of humification of the soil.

  20. D-Amino Acids in Living Higher Organisms

    NASA Astrophysics Data System (ADS)

    Fujii, Noriko

    2002-04-01

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

  1. Adsorption of amino acids and glucose by sediments of Resurrection Bay, Alaska, USA: Functional group effects

    NASA Astrophysics Data System (ADS)

    Henrichs, Susan M.; Sugai, Susan F.

    1993-02-01

    The adsorption of amino acids and glucose was investigated in sediments from Resurrection Bay, Alaska. Adsorption of the basic amino acid lysine was greater than adsorption of glutamic acid, alanine, leucine, or glucose. Formaldehyde and heat treatments were used to separate adsorption from biological uptake, but can alter adsorption significantly; formaldehyde treatment, followed by a seawater rinse, was the most satisfactory. Much of the rapid amino acid adsorption by these sediments was due to the formation of ionic bonds, since adsorbed amino acids could be extracted using concentrated solutions of amino acid, cesium chloride, sodium citrate, ammonium chloride, or sodium acetate. However, most amino acid adsorption was not reversible by ion exchange solutions, indicating that additional processes or chemical reactions occur which result in irreversible binding to sediment. Consistent with literature reports of the negative surface charge of marine particulate matter, lysine (with a net positive charge) was adsorbed to the greatest extent and had the largest cation-exchangeable adsorption. However, negatively charged amino acid functional groups also influenced adsorption. Chemical modification of sediments with reagents reactive with aldehydes decreased lysine adsorption. This suggests that reactive functional groups of sediment organic matter contribute to adsorption, consistent with a melanoidintype reaction. An estimate of the rate of amino acid adsorption indicates that adsorption could produce a significant amount of the total refractory sediment organic nitrogen.

  2. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  3. 40 CFR 721.10126 - Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with...

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... substituted benezenesulfonic acid reaction product with naphthalenesulfonato azo substituted phenyl azo... CHEMICAL SUBSTANCES Significant New Uses for Specific Chemical Substances § 721.10126 Alkyl amino substituted triazine amino substituted benezenesulfonic acid reaction product with naphthalenesulfonato...

  4. Permeability of lipid bilayers to amino acids and phosphate

    NASA Technical Reports Server (NTRS)

    Chakrabarti, A. C.; Deamer, D. W.

    1992-01-01

    Permeability coefficients for amino acid classes, including neutral, polar, hydrophobic, and charged species, were measured and compared with values for other ionic solutes such as phosphate. The rates of efflux of glycine, lysine, phenylalanine, serine and tryptophan were determined after they were passively entrapped in large unilamellar vesicles (LUVs) composed of egg phosphatidylcholine (EPC) or dimyristoylphosphatidylcholine (DMPC). The following permeability coefficients were obtained for: glycine, 5.7 x 10(-12) cm s-1 (EPC), 2.0 x 10(-11) cm s-1 (DMPC); serine, 5.5 x 10(-12) cm s-1 (EPC), 1.6 x 10(-11) cm s-1 (DMPC); lysine, 5.1 x 10(-12) cm s-1 (EPC), 1.9 x 10(-11) cm s-1 (DMPC); tryptophan, 4.1 x 10(-10) cm s-1 (EPC); and phenylalanine, 2.5 x 10(-10) cm s-1 (EPC). Decreasing lipid chain length increased permeability slightly, while variations in pH had only minor effects on the permeability coefficients of the amino acids tested. Phosphate permeability was in the range of 10(-12)-10(-13) cm s-1 depending on the pH of the medium. The values for the polar and charged amino acids were surprisingly similar to those previously measured for monovalent cations such as sodium and potassium, which are in the range of 10(-12)-10(-13) cm s-1, depending on conditions and the lipid species used. This observation suggests that the permeation rates for the neutral, polar and charged amino acids are controlled by bilayer fluctuations and transient defects, rather than partition coefficients and Born energy barriers. The results are relevant to the permeation of certain peptides into lipid bilayers during protein translocation and membrane biogenesis.

  5. Amino acids of the Murchison meteorite. I - Six carbon acyclic primary alpha-amino alkanoic acids

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Gandy, W. E.; Pizzarello, S.

    1981-01-01

    Six of the seven chain isomers of six-carbon acyclic primary alpha-amino alkanoic acids (leucine isomers) have been either identified or confirmed in hot-water extracts of the Murchison meteorite using combined gas chromatography-mass spectrometry (GC-MS) and ion exchange chromatography. 2-Amino-2-ethylbutyric acid, 2-amino-2,3-dimethylbutyric acid, pseudoleucine, and 2-methylnorvaline were positively identified by GC-MS. These amino acids have not been previously reported to occur in natural materials and may be uniquely meteoritic in origin. The presence of leucine and isoleucine (including the diastereoisomer, alloisoleucine) was confirmed. Peaks corresponding to norleucine were seen by ion-exchange and gas chromatography but characteristic mass spectra were not obtained. The alpha-branched chain isomers in this series are quantitatively the most significant. These results are compared with literature data on amino acid synthesis by electrical discharge and Fischer-Tropsch-type catalysis. Neither model system produces an amino acid suite that is completely comparable to that found in the Murchison meteorite.

  6. Roles of phytochemicals in amino acid nutrition.

    PubMed

    Kong, Xiangfeng; Wu, Guoyao; Yin, Yinlong

    2011-01-01

    Chinese herbal medicine (CHM) is often used as dietary supplements to maintain good health in animals and humans. Here, we review the current knowledge about effects of CHM (including ultra-fine Chinese herbal powder, Acanthopanax senticosus extracts, Astragalus polysaccharide, and glycyrrhetinic acid) as dietary additives on physiological and biochemical parameters in pigs, chickens and rodents. Additionally, we propose possible mechanisms for the beneficial effects of CHM on the animals. These mechanisms include (a) increased digestion and absorption of dietary amino acids; (b) altered catabolism of amino acids in the small intestine and other tissues; (c) enhanced synthesis of functional amino acids (e.g., arginine, glutamine and proline) and polyamines; and (d) improved metabolic control of nutrient utilization through cell signaling. Notably, some phytochemicals and glucocorticoids share similarities in structure and physiological actions. New research findings provide a scientific and clinical basis for the use of CHM to improve well-being in livestock species and poultry, while enhancing the efficiency of protein accretion. Results obtained from animal studies also have important implications for human nutrition and health. PMID:21196382

  7. Fatty acid-amino acid conjugates diversification in Lepidopteran caterpillars

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Fatty acid amino acid conjugates (FACs) have been found in Noctuid as well as Sphingid caterpillar oral secretions and especially volicitin [N-(17-hydroxylinolenoyl)-L-Glutamine] and its biochemical precursor, N-linolenoyl-L-glutamine, are known elicitors of induced volatile emissions in corn plants...

  8. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

  9. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

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

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid and... Significant New Uses for Specific Chemical Substances § 721.1705 Benzoic acid, 3-amino-, diazotized,...

  11. Amino acid analyses of R and CK chondrites

    NASA Astrophysics Data System (ADS)

    Burton, Aaron S.; McLain, Hannah; Glavin, Daniel P.; Elsila, Jamie E.; Davidson, Jemma; Miller, Kelly E.; Andronikov, Alexander V.; Lauretta, Dante; Dworkin, Jason P.

    2015-03-01

    Exogenous delivery of amino acids and other organic molecules to planetary surfaces may have played an important role in the origins of life on Earth and other solar system bodies. Previous studies have revealed the presence of indigenous amino acids in a wide range of carbon-rich meteorites, with the abundances and structural distributions differing significantly depending on parent body mineralogy and alteration conditions. Here we report on the amino acid abundances of seven type 3-6 CK chondrites and two Rumuruti (R) chondrites. Amino acid measurements were made on hot water extracts from these meteorites by ultrahigh-performance liquid chromatography with fluorescence detection and time-of-flight mass spectrometry. Of the nine meteorites analyzed, four were depleted in amino acids, and one had experienced significant amino acid contamination by terrestrial biology. The remaining four, comprised of two R and two CK chondrites, contained low levels of amino acids that were predominantly the straight chain, amino-terminal (n-ω-amino) acids β-alanine, and γ-amino-n-butyric acid. This amino acid distribution is similar to what we reported previously for thermally altered ureilites and CV and CO chondrites, and these n-ω-amino acids appear to be indigenous to the meteorites and not the result of terrestrial contamination. The amino acids may have been formed by Fischer-Tropsch-type reactions, although this hypothesis needs further testing.

  12. Rotational Study of Natural Amino Acid Glutamine

    NASA Astrophysics Data System (ADS)

    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.

  13. Allied Health Chemistry Laboratory: Amino Acids, Insulin, Proteins, and Skin

    ERIC Educational Resources Information Center

    Dever, David F.

    1975-01-01

    Presents a laboratory experiment specifically designed for allied health students. The students construct molecular models of amino acids, extract amino acids from their skin with hot water, and chromatographically analyze the skin extract and hydrolyzed insulin. (MLH)

  14. Single amino acid supplementation in aminoacidopathies: a systematic review

    PubMed Central

    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 protein substitution with all amino acids except the amino acids prior to the metabolic block and enriched with the amino acid that has become essential by the enzymatic defect. For some aminoacidopathies, supplementation of one or two amino acids, that have not become essential by the enzymatic defect, has been suggested. This so-called single amino acid supplementation can serve different treatment objectives, but evidence is limited. The aim of the present article is to provide a systematic review on the reasons for applications of single amino acid supplementation in aminoacidopathies treated with natural protein restriction and synthetic amino acid mixtures. PMID:24422943

  15. Amino acid synthesis in Europa's subsurface environment

    NASA Astrophysics Data System (ADS)

    Abbas, Sam H.; Schulze-Makuch, Dirk

    2008-10-01

    It has been suggested that Europa's subsurface environment may provide a haven for prebiotic evolution and the development of exotic biotic systems. The detection of hydrogen peroxide, sulfuric acid, water, hydrates and related species on the surface, coupled with observed mobility of icebergs, suggests the presence of a substantial subsurface liquid reservoir that actively exchanges materials with the surface environment. The atmospheric, surface and subsurface environments are described with their known chemistry. Three synthetic schemes using hydrogen peroxide, sulfuric acid and hydrocyanic acid leading to the production of larger biologically important molecules such as amino acids are described. Metabolic pathways based on properties of the subsurface ocean environment are detailed. Tidal heating, osmotic gradients, chemical cycling, as well as hydrothermal vents, provide energy and materials that may support a course of prebiotic evolution leading to the development or sustenance of simple biotic systems. Putative organisms may employ metabolic pathways based on chemical oxidation reduction cycles occurring in the putative subsurface ocean environment.

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

    NASA Astrophysics Data System (ADS)

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

    2016-04-01

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

  17. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2010 CFR

    2010-07-01

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

  18. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting...

  19. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting...

  20. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No....

  1. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2013 CFR

    2013-07-01

    ... 40 Protection of Environment 32 2013-07-01 2013-07-01 false Benzenesulfonic acid, amino... Specific Chemical Substances § 721.1643 Benzenesulfonic acid, amino substituted phenylazo-. (a) Chemical... as a benzenesulfonic acid, amino substituted phenylazo- (PMN P-95-86) is subject to reporting...

  2. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2012 CFR

    2012-07-01

    ... 40 Protection of Environment 32 2012-07-01 2012-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No....

  3. 40 CFR 721.2584 - Dodecanoic acid, 12-amino-.

    Code of Federal Regulations, 2014 CFR

    2014-07-01

    ... 40 Protection of Environment 31 2014-07-01 2014-07-01 false Dodecanoic acid, 12-amino-. 721.2584... Substances § 721.2584 Dodecanoic acid, 12-amino-. (a) Chemical substance and significant new uses subject to reporting. (1) The chemical substance identified as dodecanoic acid, 12-amino- (PMN P-98-0823; CAS No....

  4. 40 CFR 721.1643 - Benzenesulfonic acid, amino substituted phenylazo-.

    Code of Federal Regulations, 2011 CFR

    2011-07-01

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

  5. Nutritional and medicinal aspects of D-amino acids

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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 nu...

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

    Technology Transfer Automated Retrieval System (TEKTRAN)

    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...

  7. Amino acid sequence of Salmonella typhimurium branched-chain amino acid aminotransferase.

    PubMed

    Feild, M J; Nguyen, D C; Armstrong, F B

    1989-06-13

    The complete amino acid sequence of the subunit of branched-chain amino acid aminotransferase (transaminase B, EC 2.6.1.42) of Salmonella typhimurium was determined. An Escherichia coli recombinant containing the ilvGEDAY gene cluster of Salmonella was used as the source of the hexameric enzyme. The peptide fragments used for sequencing were generated by treatment with trypsin, Staphylococcus aureus V8 protease, endoproteinase Lys-C, and cyanogen bromide. The enzyme subunit contains 308 residues and has a molecular weight of 33,920. To determine the coenzyme-binding site, the pyridoxal 5-phosphate containing enzyme was treated with tritiated sodium borohydride prior to trypsin digestion. Peptide map comparisons with an apoenzyme tryptic digest and monitoring radioactivity incorporation allowed identification of the pyridoxylated peptide, which was then isolated and sequenced. The coenzyme-binding site is the lysyl residue at position 159. The amino acid sequence of Salmonella transaminase B is 97.4% identical with that of Escherichia coli, differing in only eight amino acid positions. Sequence comparisons of transaminase B to other known aminotransferase sequences revealed limited sequence similarity (24-33%) when conserved amino acid substitutions are allowed and alignments were forced to occur on the coenzyme-binding site. PMID:2669973

  8. 2-Chlorotrityl chloride resin. Studies on anchoring of Fmoc-amino acids and peptide cleavage.

    PubMed

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

    1991-06-01

    The esterification of 2-chlorotrityl chloride resin with Fmoc-amino acids in the presence of DIEA is studied under various conditions. High esterification yields are obtained using 0.6 equiv. Fmoc-amino acid/mmol resin in DCM or DCE, in 25 min, at room temperature. The reaction proceeds without by product formation even in the case of Fmoc-Asn and Fmoc-Gln. The quantitative and easy cleavage of amino acids and peptides from 2-chlorotrityl resin, by using AcOH/TFE/DCM mixtures, is accomplished within 15-60 min at room temperature, while t-butyl type protecting groups remain unaffected. Under these exceptionally mild conditions 2-chlorotrityl cations generated during the cleavage of amino acids and peptides from resin do not attack the nucleophilic side chains of Trp, Met, and Tyr. PMID:1917309

  9. Interaction and dynamics of ionic liquids based on choline and amino acid anions

    SciTech Connect

    Campetella, M.; Bodo, E. Caminiti, R. Martino, A.; Gontrani, L.; D’Apuzzo, F.; Lupi, S.

    2015-06-21

    The combination of amino acid anions with the choline cation gives origin to a new and potentially important class of organic ionic liquids that might represent a viable and bio-compatible alternative with respect to the traditional ones. We present here a detailed study of the bulk phase of the prototype system composed of the simplest amino acid (alanine) anion and the choline cation, based on ab initio and classical molecular dynamics. Theoretical findings have been validated by comparing with accurate experimental X-ray diffraction data and infrared spectra. We find that hydrogen bonding (HB) features in these systems are crucial in establishing their local geometric structure. We have also found that these HBs once formed are persistent and that the proton resides exclusively on the choline cation. In addition, we show that a classical force field description for this particular ionic liquid can be accurately performed by using a slightly modified version of the generalized AMBER force field.

  10. Interaction and dynamics of ionic liquids based on choline and amino acid anions

    NASA Astrophysics Data System (ADS)

    Campetella, M.; Bodo, E.; Caminiti, R.; Martino, A.; D'Apuzzo, F.; Lupi, S.; Gontrani, L.

    2015-06-01

    The combination of amino acid anions with the choline cation gives origin to a new and potentially important class of organic ionic liquids that might represent a viable and bio-compatible alternative with respect to the traditional ones. We present here a detailed study of the bulk phase of the prototype system composed of the simplest amino acid (alanine) anion and the choline cation, based on ab initio and classical molecular dynamics. Theoretical findings have been validated by comparing with accurate experimental X-ray diffraction data and infrared spectra. We find that hydrogen bonding (HB) features in these systems are crucial in establishing their local geometric structure. We have also found that these HBs once formed are persistent and that the proton resides exclusively on the choline cation. In addition, we show that a classical force field description for this particular ionic liquid can be accurately performed by using a slightly modified version of the generalized AMBER force field.

  11. Biosynthesis of amino acids in Clostridium pasteurianum

    PubMed Central

    Dainty, R. H.; Peel, J. L.

    1970-01-01

    1. Clostridium pasteurianum was grown on a synthetic medium with the following carbon sources: (a) 14C-labelled glucose, alone or with unlabelled aspartate or glutamate, or (b) unlabelled glucose plus 14C-labelled aspartate, glutamate, threonine, serine or glycine. The incorporation of 14C into the amino acids of the cell protein was examined. 2. In both series of experiments carbon from exogenous glutamate was incorporated into proline and arginine; carbon from aspartate was incorporated into glutamate, proline, arginine, lysine, methionine, threonine, isoleucine, glycine and serine. Incorporations from the other exogenous amino acids indicated the metabolic sequence: aspartate → threonine → glycine ⇌ serine. 3. The following activities were demonstrated in cell-free extracts of the organism: (a) the formation of aspartate by carboxylation of phosphoenolpyruvate or pyruvate, followed by transamination; (b) the individual reactions of the tricarboxylic acid route to 2-oxoglutarate from oxaloacetate; glutamate dehydrogenase was not detected; (c) the conversion of aspartate into threonine via homoserine; (d) the conversion of threonine into glycine by a constitutive threonine aldolase; (e) serine transaminase, phosphoserine transaminase, glycerate dehydrogenase and phosphoglycerate dehydrogenase. This last activity was abnormally high. 4. The combined evidence indicates that in C. pasteurianum the biosynthetic role of aspartate and glutamate is generally similar to that in aerobic and facultatively aerobic organisms, but that glycine is synthesized from glucose via aspartate and threonine. PMID:5419750

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

    PubMed Central

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

    2015-01-01

    Disruptions in gut microbiota composition and function are increasingly implicated in the pathogenesis of obesity, insulin resistance, and type 2 diabetes mellitus. The functional output of the gut microbiota, including short-chain fatty acids and amino acids, are thought to be important modulators underlying the development of these disorders. Gut bacteria can alter the bioavailability of amino acids by utilization of several amino acids originating from both alimentary and endogenous proteins. In turn, gut bacteria also provide amino acids to the host. This could have significant implications in the context of insulin resistance and type 2 diabetes mellitus, conditions associated with elevated systemic concentrations of certain amino acids, in particular the aromatic and branched-chain amino acids. Moreover, several amino acids released by gut bacteria can serve as precursors for the synthesis of short-chain fatty acids, which also play a role in the development of obesity. In this review, we aim to compile the available evidence on the contribution of microbial amino acids to host amino acid homeostasis, and to assess the role of the gut microbiota as a determinant of amino acid and short-chain fatty acid perturbations in human obesity and type 2 diabetes mellitus. PMID:25894657

  13. Organic geochemistry of amino acids: Precambrian to recent

    SciTech Connect

    Engel, M.H.; Macko, S.A.

    1985-01-01

    Since the discovery of amino acids in fossils (Abelson, 1954), considerable effort has been made to elucidate the origin and distribution of amino acids in geologic materials. Racemization and decomposition reactions of amino acids and peptides derived via the natural hydrolysis of protein constituents of organisms have been extensively studied. While the ubiquity of amino acids presents a challenge for discerning their indigeneity in geologic samples, careful analyses have resulted in successful applications of amino acid racemization and decomposition reactions for investigations of geochronologic, paleoclimatic, stratigraphic, diagenetic and chemotaxonomic problems for Quaternary age samples. An investigation of amino acids in sediments from Baffin Island fjords indicates that their distribution may also provide data with respect to the relative contributions of marine and terrigenous organic matter to recent sediments. While the absence of unstable amino acids and the presence of racemic amino acids in a sample may preclude very recent contamination, the possibility of retardation of amino acid racemization rates subsequent to geopolymer formation must also be considered. Studies of amino acids in Paleozoic, Mesozoic and early Cenozoic age samples are limited. Precambrian samples, however, have received much attention, given the potential (however slight) for isolating compounds representative of the earliest living systems. A future approach for elucidating the origin(s) of amino acids in ancient samples may be analyses of their individual stable isotopic compositions.

  14. Dissolved amino acids in oceanic basaltic basement fluids

    NASA Astrophysics Data System (ADS)

    Lin, Huei-Ting; Amend, Jan P.; LaRowe, Douglas E.; Bingham, Jon-Paul; Cowen, James P.

    2015-09-01

    The oceanic basaltic basement contains the largest aquifer on Earth and potentially plays an important role in the global carbon cycle as a net sink for dissolved organic carbon (DOC). However, few details of the organic matter cycling in the subsurface are known because great water depths and thick sediments typically hinder direct access to this environment. In an effort to examine the role of water-rock-microorganism interaction on organic matter cycling in the oceanic basaltic crust, basement fluid samples collected from three borehole observatories installed on the eastern flank of the Juan de Fuca Ridge were analyzed for dissolved amino acids. Our data show that dissolved free amino acids (1-13 nM) and dissolved hydrolyzable amino acids (43-89 nM) are present in the basement. The amino acid concentrations in the ridge-flank basement fluids are at the low end of all submarine hydrothermal fluids reported in the literature and are similar to those in deep seawater. Amino acids in recharging deep seawater, in situ amino acid production, and diffusional input from overlying sediments are potential sources of amino acids in the basement fluids. Thermodynamic modeling shows that amino acid synthesis in the basement can be sustained by energy supplied from inorganic substrates via chemolithotrophic metabolisms. Furthermore, an analysis of amino acid concentrations and compositions in basement fluids support the notion that heterotrophic activity is ongoing. Similarly, the enrichment of acidic amino acids and depletion of hydrophobic ones relative to sedimentary particulate organic matter suggests that surface sorption and desorption also alters amino acids in the basaltic basement. In summary, although the oceanic basement aquifer is a net sink for deep seawater DOC, similar amino acid concentrations in basement aquifer and deep seawater suggest that DOC is preferentially removed in the basement over dissolved amino acids. Our data also suggest that organic carbon

  15. Protein and Amino Acid Requirements during Pregnancy.

    PubMed

    Elango, Rajavel; Ball, Ronald O

    2016-07-01

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

  16. Isotope composition of carbon in amino acids of solid bitumens

    NASA Astrophysics Data System (ADS)

    Shanina, S. N.; Bushnev, D. A.

    2014-06-01

    Primary data are presented on the isotope composition of carbon in individual amino acids from solid bitumens and several biological objects. The amino acids of biological objects are characterized by wide variations of the isotope composition of carbon. This fact occurs owing to the difference in biochemical paths of metabolism resulting in the synthesis of individual amino acids. The δ13C values are somewhat decreased for individual amino acids in asphaltenes, varying from -7.7 to -31.7‰. The carbon of amino acids is weighted in kerits from Bad'el' compared to asphaltenes. All the natural bitumens retain the characteristic trend for natural substances: the isotopically heavy and light amino acids by carbon are glycine and leucine, respectively. The isotope composition of amino-acid carbon is lightened compared to natural bitumens in the samples formed under a pronounced thermal impact (asphalt-like crust and kirishite).

  17. Intermolecular Vibrations of Hydrophobic Amino Acids

    NASA Astrophysics Data System (ADS)

    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

  18. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the snythesis methods of the prior art.

  19. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  20. Synthesis of alpha-amino acids

    DOEpatents

    Davis, Jr., Jefferson W.

    1983-01-01

    A method for synthesizing alpha amino acids proceding through novel intermediates of the formulas: R.sub.1 R.sub.2 C(OSOCl)CN, R.sub.1 R.sub.2 C(Cl)CN and [R.sub.1 R.sub.2 C(CN)O].sub.2 SO wherein R.sub.1 and R.sub.2 are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 12 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art.

  1. Interactions of amino acids with oxidized guanine in the gas phase associated with the protection of damaged DNA.

    PubMed

    Zhao, Jing; Yang, Hongfang; Zhang, Meng; Bu, Yuxiang

    2013-04-01

    Density functional theory calculations were employed to study the stabilization process of the guanine radical cation through amino acid interactions as well as to understand the protection mechanisms. On the basis of our calculations, several protection mechanisms are proposed in this work subject to the type of the amino acid. Our results indicate that a series of three-electron bonds can be formed between the amino acids and the guanine radical cation which may serve as relay stations supporting hole transport. In the three-electron-bonded, π-π-stacked, and H-bonded modes, amino acids can protect guanine from oxidation or radiation damage by sharing the hole, while amino acids with reducing properties can repair the guanine radical cation through proton-coupled electron transfer or electron transfer. Another important finding is that positively charged amino acids (ArgH(+), LysH(+), and HisH(+)) can inhibit ionization of guanine through raising its ionization potential. In this situation, a negative dissociation energy for hydrogen bonds in the hole-trapped and positively charged amino acid-Guanine dimer is observed, which explains the low hole-trapping efficiency. We hope that this work provides valuable information on how to protect DNA from oxidation- or radiation-induced damages in biological systems. PMID:23427004

  2. Skeletal muscle amino acid transporter expression is increased in young and older adults following resistance exercise

    PubMed Central

    Fry, Christopher S.; Glynn, Erin L.; Timmerman, Kyle L.; Dickinson, Jared M.; Walker, Dillon K.; Gundermann, David M.; Volpi, Elena; Rasmussen, Blake B.

    2011-01-01

    Amino acid transporters and mammalian target of rapamycin complex 1 (mTORC1) signaling are important contributors to muscle protein anabolism. Aging is associated with reduced mTORC1 signaling following resistance exercise, but the role of amino acid transporters is unknown. Young (n = 13; 28 ± 2 yr) and older (n = 13; 68 ± 2 yr) subjects performed a bout of resistance exercise. Skeletal muscle biopsies (vastus lateralis) were obtained at basal and 3, 6, and 24 h postexercise and were analyzed for amino acid transporter mRNA and protein expression and regulators of amino acid transporter transcription utilizing real-time PCR and Western blotting. We found that basal amino acid transporter expression was similar in young and older adults (P > 0.05). Exercise increased L-type amino acid transporter 1/solute-linked carrier (SLC) 7A5, CD98/SLC3A2, sodium-coupled neutral amino acid transporter 2/SLC38A2, proton-assisted amino acid transporter 1/SLC36A1, and cationic amino acid transporter 1/SLC7A1 mRNA expression in both young and older adults (P < 0.05). L-type amino acid transporter 1 and CD98 protein increased only in younger adults (P < 0.05). eukaryotic initiation factor 2 α-subunit (S52) increased similarly in young and older adults postexercise (P < 0.05). Ribosomal protein S6 (S240/244) and activating transcription factor 4 nuclear protein expression tended to be higher in the young, while nuclear signal transducer and activator of transcription 3 (STAT3) (Y705) was higher in the older subjects postexercise (P < 0.05). These results suggest that the rapid upregulation of amino acid transporter expression following resistance exercise may be regulated differently between the age groups, but involves a combination of mTORC1, activating transcription factor 4, eukaryotic initiation factor 2 α-subunit, and STAT3. We propose an increase in amino acid transporter expression may contribute to enhanced amino acid sensitivity following exercise in young and older

  3. Sodium-coupled sugar and amino acid transport in an acidic microenvironment.

    PubMed

    Ahearn, G A; Clay, L P

    1988-01-01

    1. Nutrient transport mechanisms of lobster hepatopancreatic epithelial brush border membrane vesicles (BBMV) are strongly influenced by the acidic nature of the tubular lumen. 2. Sodium-dependent glucose uptake by BBMV was electrogenic and was stimulated at low pH by reducing sugar transport Ki, without affecting JM. 3. Glutamate was largely transported in zwitterionic form at pH 4.0 by an electrically silent cotransport mechanism with both Na and Cl. 4. Increased H+ concentration tripled the apparent membrane permeability to glutamate as well as the amino acid transport JM. 5. At pH 4.0 leucine was transported as a cation by two dissimilar carrier systems: a Na-independent process shared by polar amino acids, and an electroneutral Na-2Cl-dependent mechanism shared with non-polar amino acids. 6. A model is proposed for hepatopancreatic BBMV at acidic pH which employs ionic chemical gradients and membrane potential as nutrient transport driving forces. PMID:2902970

  4. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    NASA Technical Reports Server (NTRS)

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

    2010-01-01

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

  5. Extraterrestrial amino acids in the Almahata Sitta meteorite

    NASA Astrophysics Data System (ADS)

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

    2010-10-01

    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, β-amino-n-butyric acid, 2-amino-2-methylbutanoic acid (isovaline), and 2-aminopentanoic acid (norvaline) in the meteorite were racemic (D/L ˜ 1), indicating that these amino acids are indigenous to the meteorite and not terrestrial contaminants. Several other nonprotein amino acids were also identified in the meteorite above background levels including α-aminoisobutyric acid (α-AIB), 4-amino-2-methylbutanoic acid, 4-amino-3-methylbutanoic acid, and 3-, 4-, and 5-aminopentanoic acid. The total abundances of isovaline and α-AIB in Almahata Sitta are approximately 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 CI, 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, or introduced as a contaminant from unrelated meteorite clasts and chemically altered by α-decarboxylation.

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

    PubMed

    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. PMID:26807980

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

    NASA Technical Reports Server (NTRS)

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

    1999-01-01

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

  8. Physiological Adaptation to the Loss of Amino Acid Transport Ability

    PubMed Central

    DeBusk, Ruth M.; Ogilvie-Villa, Susan

    1982-01-01

    A strain of Neurospora crassa devoid of constitutive amino acid transport ability can utilize arginine as the sole nitrogen source. Nitrogen starvation, presence of arginine, and mutational inactivation of the general permease are key factors in signaling production of an extracellular enzyme which removes the alpha-amino group from the amino acid. PMID:6214547

  9. Accumulated analyses of amino acid precursors in returned lunar samples

    NASA Technical Reports Server (NTRS)

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

    1973-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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

  11. Conformational properties of oxazoline-amino acids

    NASA Astrophysics Data System (ADS)

    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.

  12. Capillary electrophoresis analysis of organic amines and amino acids in saline and acidic samples using the Mars organic analyzer.

    PubMed

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

    2009-11-01

    The Mars Organic Analyzer (MOA) has enabled the sensitive detection of amino acid and amine biomarkers in laboratory standards and in a variety of field sample tests. However, the MOA is challenged when samples are extremely acidic and saline or contain polyvalent cations. Here, we have optimized the MOA analysis, sample labeling, and sample dilution buffers to handle such challenging samples more robustly. Higher ionic strength buffer systems with pK(a) values near pH 9 were developed to provide better buffering capacity and salt tolerance. The addition of ethylaminediaminetetraacetic acid (EDTA) ameliorates the negative effects of multivalent cations. The optimized protocol utilizes a 75 mM borate buffer (pH 9.5) for Pacific Blue labeling of amines and amino acids. After labeling, 50 mM (final concentration) EDTA is added to samples containing divalent cations to ameliorate their effects. This optimized protocol was used to successfully analyze amino acids in a saturated brine sample from Saline Valley, California, and a subcritical water extract of a highly acidic sample from the Río Tinto, Spain. This work expands the analytical capabilities of the MOA and increases its sensitivity and robustness for samples from extraterrestrial environments that may exhibit pH and salt extremes as well as metal ions. PMID:19968460

  13. Morphology and Structure of Amino-fatty Acid Intercalated Montmorillonite

    NASA Astrophysics Data System (ADS)

    Reyes, Larry; Sumera, Florentino

    2015-04-01

    Natural clays and its modified forms have been studied for their wide range of applications, including polymer-layered silicate, catalysts and adsorbents. For nanocomposite production, montmorillonite (MMT) clays are often modified with organic surfactants to favor its intermixing with the polymer matrix. In the present study, Na+-montmorillonite (Na+-MMT) was subjected to organo-modification with a protonated 12-aminolauric acid (12-ALA). The amount of amino fatty acid surfactants loaded was 25, 50, 100 and 200% the cation exchange capacity (CEC) of Na+-MMT (25CEC-AMMT, 50CEC-AMMT, 100CEC-AMMT and 200CEC-AMMT). Fatty acid-derived surfactants are an attractive resource of intercalating agents for clays due to their renewability and abundance. X-ray diffraction (XRD) and Fourier Transform Infrared Spectroscopy (FTIR) were performed to determine the occurrence of intercalation of 12-ALA and their molecular structure in the clay's silicates. XRD analysis revealed that the interlayer spacing between the alumino-silicate layers increased from 1.25 nm to 1.82 nm with increasing ALA content. The amino fatty acid chains were considered to be in a flat monolayer structure at low surfactant loading, and a bilayered to a pseudotrilayered structure at high surfactant loading. On the other hand, FTIR revealed that the alkyl chains adopt a gauche conformation, indicating their disordered state based on their CH2symmetric and asymmetric vibrations. Thermogravimetric analyses (TGA) allows the determination of the moisture and organic content in clays. Here, TGA revealed that the surfactant in the clay was thermally stable, with Td ranging from 353° C to 417° C. The difference in the melting behavior of the pristine amino fatty acids and confined fatty acids in the interlayer galleries of the clay were evaluated by Differential Scanning Calorimerty (DSC). The melting temperatures (Tm) of the amino fatty acid in the clay were initially found to be higher than those of the free

  14. Amino acids of the Nogoya and Mokoia carbonaceous chondrites

    NASA Technical Reports Server (NTRS)

    Cronin, J. R.; Moore, C. B.

    1976-01-01

    Amino acids were found in acid hydrolyzed, hot water extracts of the Nogoya (C2) and Mokoia (C3V) chondrites. About 40 n moles/g of amino acids were found in the Nogoya extract while Mokoia contained less than 1 n mole/g. The amino acid composition of Nogoya differs from that of other C2 chondrites studied earlier. The results from Mokoia are similar to previous data obtained from the C3V chondrite Allende.

  15. Design assembly of an inexpensive, automated microbore amino acid analyzer: separation and quantitation of amino acids in physiological fluids.

    PubMed

    Beecher, G R

    1978-01-01

    An amino acid analyzer capable of separating and quantitating 0.5 to 20 n moles of each ninhydrin-positive compound in physiological fluids has been designed and assembled from commercially available components. The buffer sequence, column temperature change and sample application are controlled by an automatic programmer constructed from a series of timers. The liquid delivery protion of the instrument consists of a series of polystyrene and stainless steel chambers pressurized with argon and connected through valves and manifolds to conventional positive displacement pumps. The column is highly polished stainless steel tubing (0.21-cm ID) packed with 9-mu cation exchange resin. Micro colorimeters, equipped with appropriate interference filters and small-volume (2-8 mu 1) flow cells, are used as detectors. The sample loader is a dual 20-port automatic valve containing 25-mu1 sample loops. Small-bore teflon tubing (32 AWG), interconnected with tubing adapters and connectors, is used for buffer lines and reaction coil (100 degree C); ninhydrin lines are 1/16-inch stainless steel tubing. Separation of 42 ninhydrin positive compounds, including column equilibration, is accomplished in 5 hours. Procedures for the extraction of amino acids from physiological fluids and tissues as well as the preliminary clean-up of these extracts are also described. PMID:727032

  16. Prebiotic Synthesis of Hydrophobic and Protein Amino Acids

    PubMed Central

    Ring, David; Wolman, Yecheskel; Friedmann, Nadav; Miller, Stanley L.

    1972-01-01

    The formation of amino acids by the action of electric discharges on a mixture of methane, nitrogen, and water with traces of ammonia was studied in detail. The presence of glycine, alanine, α-amino-n-butyric acid, α-aminoisobutyric acid, valine, norvaline, isovaline, leucine, isoleucine, alloisoleucine, norleucine, proline, aspartic acid, glutamic acid, serine, threonine, allothreonine, α-hydroxy-γ-aminobutyric acid, and α,γ-diaminobutyric acid was confirmed by ion-exchange chromatography and gas chromatography-mass spectrometry. All of the primary α-amino acids found in the Murchison Meteorite have been synthesized by this electric discharge experiment. PMID:4501592

  17. A reexamination of amino acids in lunar soil

    NASA Astrophysics Data System (ADS)

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

    1993-03-01

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

  18. A reexamination of amino acids in lunar soil

    NASA Technical Reports Server (NTRS)

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

    1993-01-01

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

  19. High-performance liquid chromatography of amino acids in urine and cerebrospinal fluid.

    PubMed

    Lam, S; Azumaya, H; Karmen, A

    1984-10-19

    Two different methods for analyzing amino acids by reversed-phase high-performance liquid chromatography (HPLC), both of which can separate D- and L- stereoisomers, have been used for studying the amino acid composition of cerebrospinal fluid (CSF) and urine. One method, by which Dns derivatives of amino acids are separated as mixed chelate complexes with Cu(II) and a single stereoisomer of a second amino acid, was used to analyze CSF. CSF contains ca. 10 mumole/l per amino acid, compared to 100 mumole/l in serum. The high sensitivity of fluorescence detection enabled complete analysis, starting with 50 microliter of fluid. The second method, which uses lower concentrations of both the copper and the second amino acid and detects amino acids by the change in absorbance of the copper complex, was used to measure the urine concentration of the lysine metabolite, pipecolic acid (piperidine-2-carboxylic acid), a secondary amino acid that is difficult to detect by the more usual detection methods. Our procedure involves passing urine through a cation-exchange column, collecting the fraction containing pipecolic acid, and chromatographing it on a reversed-phase HPLC column with a mobile phase containing L-aspartame and Cu(II). To assess the utility of the method, urine samples from a patient given loading doses of D- or L-isomers were analyzed. When either isomer was administered, both D- and L-isomers were detected, but in different proportions. Varying proportions and concentrations of both isomers were also detected in the urines of patients with hyperpipecolatemia from different metabolic abnormalities. PMID:6501504

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

    NASA Astrophysics Data System (ADS)

    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.

  1. Cationic RAFT polymerization using ppm concentrations of organic acid.

    PubMed

    Uchiyama, Mineto; Satoh, Kotaro; Kamigaito, Masami

    2015-02-01

    A metal-free, cationic, reversible addition-fragmentation chain-transfer (RAFT) polymerization was proposed and realized. A series of thiocarbonylthio compounds were used in the presence of a small amount of triflic acid for isobutyl vinyl ether to give polymers with controlled molecular weight of up to 1×10(5) and narrow molecular-weight distributions (Mw /Mn <1.1). This "living" or controlled cationic polymerization is applicable to various electron-rich monomers including vinyl ethers, p-methoxystyrene, and even p-hydroxystyrene that possesses an unprotected phenol group. A transformation from cationic to radical RAFT polymerization enables the synthesis of block copolymers between cationically and radically polymerizable monomers, such as vinyl ether and vinyl acetate or methyl acrylate. PMID:25511364

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

    EPA Science Inventory

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

  3. Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

    NASA Technical Reports Server (NTRS)

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

    2009-01-01

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

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

    SciTech Connect

    Unkefer, C.J.; Martinez, R.A.; Silks, L.A. III; Lodwig, S.N.

    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.

  5. Geochemistry of amino acids in shells of the clam Saxidomus

    USGS Publications Warehouse

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

    1980-01-01

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

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

    NASA Technical Reports Server (NTRS)

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

    2015-01-01

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

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

    NASA Astrophysics Data System (ADS)

    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. Survival of Amino Acids in Micrometeorites During Atmospheric Entry

    NASA Technical Reports Server (NTRS)

    Glavin, Daniel P.; Bada, Jeffrey L.

    2003-01-01

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

  9. Trophic spectra under the lens of amino acid isotopic analysis

    Technology Transfer Automated Retrieval System (TEKTRAN)

    Recent advances in compound specific isotopic ratio analysis (CSIRA) have allowed researchers to measure trophic fractionation of 15N in specific amino acids, namely glutamic acid and phenylalanine. These amino acids have proven useful in food web studies because of the wide and consistent disparity...

  10. The Origin of Amino Acids in Lunar Regolith Samples

    NASA Technical Reports Server (NTRS)

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

    2016-01-01

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

  11. Roles of urea production, ammonium excretion, and amino acid oxidation in acid-base balance.

    PubMed

    Mackenzie, W

    1986-02-01

    Atkinson and colleagues recently proposed several concepts that contrast with traditional views: first, that acid-base balance is regulated chiefly by the reactions leading to urea production in the liver; second, that ammonium excretion by the kidney plays no role in acid-base homeostasis; and third, that ammonium does not stimulate ureagenesis (except indirectly). To examine these concepts, plasma ions other than bicarbonate are categorized as 1) fixed cations (Na+, K+, Ca2+, and Mg2+, symbolized M+) and anions (Cl-), 2) buffer anions (A-), 3) other anions (X-), and 4) ammonium plus charged amino groups (N+). Since electroneutrality dictates that M+ + N+ = Cl- + HCO3- + A- + X-, it follows that delta HCO3- = delta(M+ - Cl-) - delta A- - delta X- + delta N+. Therefore acid-base disturbances (changes in HCO3-) can be categorized as to how they affect bodily content and hence plasma concentration of each of these four types of ions. The stoichiometry of ureagenesis, glutamine hydrolysis, ammonium and titratable acid excretion, oxidation of neutral, acidic, and basic amino acids, and oxidation of methionine, phosphoserine, and protein are examined to see how they alter these quantities. It is concluded that 1) although ureagenesis is pH dependent and also counteracts a tendency of amino acid oxidation to cause alkalosis, this tendency is inherently limited by the hyperammonemia (delta N+) that necessarily accompanies it, 2) ammonium excretion is equivalent to hydrogen excretion in its effects on acid-base balance if, and only if, it occurs in exchange for sodium or is accompanied by chloride excretion and only when the glutamate generated by glutamine hydrolysis is oxidized.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3511732

  12. Kinetic Trapping of Metastable Amino Acid Polymorphs

    PubMed Central

    2015-01-01

    Second harmonic generation (SHG) microscopy measurements indicate that inkjet-printed racemic solutions of amino acids can produce nanocrystals trapped in metastable polymorph forms upon rapid solvent evaporation. Polymorphism impacts the composition, distribution, and physico-kinetic properties of organic solids, with energetic arguments favoring the most stable polymorph. In this study, unfavored noncentrosymmetric crystal forms were observed by SHG microscopy. Polarization-dependent SHG measurement and synchrotron X-ray microdiffraction analysis of individual printed drops are consistent with formation of homochiral crystal production. Fundamentally, these results provide evidence supporting the ubiquity of Ostwald’s Rule of Stages, describing the hypothesized transitioning of crystals between metastable polymorphic forms in the early stages of crystal formation. Practically, the presence of homochiral metastable forms has implications on chiral resolution and on solid form preparations relying on rapid solvent evaporation. PMID:24451055

  13. Synthesis of alpha-amino acids

    DOEpatents

    Davis, J.W. Jr.

    1983-01-25

    A method is described for synthesizing alpha amino acids proceeding through novel intermediates of the formulas: R[sub 1]R[sub 2]C(OSOCl)CN, R[sub 1]R[sub 2]C(Cl)CN and [R[sub 1]R[sub 2]C(CN)O][sub 2]SO wherein R[sub 1] and R[sub 2] are each selected from hydrogen monovalent substituted and unsubstituted hydrocarbon radicals of 1 to 10 carbon atoms. The use of these intermediates allows the synthesis steps to be exothermic and results in an overall synthesis method which is faster than the synthesis methods of the prior art. No Drawings

  14. Kinetic trapping of metastable amino acid polymorphs.

    PubMed

    Chowdhury, Azhad U; Dettmar, Christopher M; Sullivan, Shane Z; Zhang, Shijie; Jacobs, Kevin T; Kissick, David J; Maltais, Thora; Hedderich, Hartmut G; Bishop, Patricia A; Simpson, Garth J

    2014-02-12

    Second harmonic generation (SHG) microscopy measurements indicate that inkjet-printed racemic solutions of amino acids can produce nanocrystals trapped in metastable polymorph forms upon rapid solvent evaporation. Polymorphism impacts the composition, distribution, and physico-kinetic properties of organic solids, with energetic arguments favoring the most stable polymorph. In this study, unfavored noncentrosymmetric crystal forms were observed by SHG microscopy. Polarization-dependent SHG measurement and synchrotron X-ray microdiffraction analysis of individual printed drops are consistent with formation of homochiral crystal production. Fundamentally, these results provide evidence supporting the ubiquity of Ostwald's Rule of Stages, describing the hypothesized transitioning of crystals between metastable polymorphic forms in the early stages of crystal formation. Practically, the presence of homochiral metastable forms has implications on chiral resolution and on solid form preparations relying on rapid solvent evaporation. PMID:24451055

  15. Understanding and identifying amino acid repeats.

    PubMed

    Luo, Hong; Nijveen, Harm

    2014-07-01

    Amino acid repeats (AARs) are abundant in protein sequences. They have particular roles in protein function and evolution. Simple repeat patterns generated by DNA slippage tend to introduce length variations and point mutations in repeat regions. Loss of normal and gain of abnormal function owing to their variable length are potential risks leading to diseases. Repeats with complex patterns mostly refer to the functional domain repeats, such as the well-known leucine-rich repeat and WD repeat, which are frequently involved in protein–protein interaction. They are mainly derived from internal gene duplication events and stabilized by ‘gate-keeper’ residues, which play crucial roles in preventing inter-domain aggregation. AARs are widely distributed in different proteomes across a variety of taxonomic ranges, and especially abundant in eukaryotic proteins. However, their specific evolutionary and functional scenarios are still poorly understood. Identifying AARs in protein sequences is the first step for the further investigation of their biological function and evolutionary mechanism. In principle, this is an NP-hard problem, as most of the repeat fragments are shaped by a series of sophisticated evolutionary events and become latent periodical patterns. It is not possible to define a uniform criterion for detecting and verifying various repeat patterns. Instead, different algorithms based on different strategies have been developed to cope with different repeat patterns. In this review, we attempt to describe the amino acid repeat-detection algorithms currently available and compare their strategies based on an in-depth analysis of the biological significance of protein repeats. PMID:23418055

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

    NASA Technical Reports Server (NTRS)

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

    1985-01-01

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

  17. Gas-Phase Acidities of Phosphorylated Amino Acids.

    PubMed

    Stover, Michele L; Plummer, Chelsea E; Miller, Sean R; Cassady, Carolyn J; Dixon, David A

    2015-11-19

    Gas-phase acidities and heats of formation have been predicted at the G3(MP2)/SCRF-COSMO level of theory for 10 phosphorylated amino acids and their corresponding amides, including phospho-serine (pSer), -threonine (pThr), and -tyrosine (pTyr), providing the first reliable set of these values. The gas-phase acidities (GAs) of the three named phosphorylated amino acids and their amides have been determined using proton transfer reactions in a Fourier transform ion cyclotron mass spectrometer. Excellent agreement was found between the experimental and predicted GAs. The phosphate group is the deprotonation site for pSer and pThr and deprotonation from the carboxylic acid generated the lowest energy anion for pTyr. The infrared spectra were calculated for six low energy anions of pSer, pThr, and pTyr. For deprotonated pSer and pThr, good agreement is found between the experimental IRMPD spectra and the calculated spectra for our lowest energy anion structure. For pTyr, the IR spectra for a higher energy phosphate deprotonated structure is in good agreement with experiment. Additional experiments tested electrospray ionization (ESI) conditions for pTyr and determined that variations in solvent, temperature, and voltage can result in a different experimental GA value, indicating that ESI conditions affect the conformation of the pTyr anion. PMID:26492552

  18. Amino acids in the cultivation of mammalian cells.

    PubMed

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

    2016-05-01

    Amino acids are crucial for the cultivation of mammalian cells. This importance of amino acids was realized soon after the development of the first cell lines, and a solution of a mixture of amino acids has been supplied to cultured cells ever since. The importance of amino acids is further pronounced in chemically defined mammalian cell culture media, making the consideration of their biological and chemical properties necessary. Amino acids concentrations have been traditionally adjusted to their cellular consumption rates. However, since changes in the metabolic equilibrium of amino acids can be caused by changes in extracellular concentrations, metabolomics in conjunction with flux balance analysis is being used in the development of culture media. The study of amino acid transporters is also gaining importance since they control the intracellular concentrations of these molecules and are influenced by conditions in cell culture media. A better understanding of the solubility, stability, dissolution kinetics, and interactions of these molecules is needed for an exploitation of these properties in the development of dry powdered chemically defined media for mammalian cells. Due to the complexity of these mixtures however, this has proven to be challenging. Studying amino acids in mammalian cell culture media will help provide a better understanding of how mammalian cells in culture interact with their environment. It would also provide insight into the chemical behavior of these molecules in solutions of complex mixtures, which is important in the understanding of the contribution of individual amino acids to protein structure. PMID:26832172

  19. Analysis of amino acid and codon usage in Paramecium bursaria.

    PubMed

    Dohra, Hideo; Fujishima, Masahiro; Suzuki, Haruo

    2015-10-01

    The ciliate Paramecium bursaria harbors the green-alga Chlorella symbionts. We reassembled the P. bursaria transcriptome to minimize falsely fused transcripts, and investigated amino acid and codon usage using the transcriptome data. Surface proteins preferentially use smaller amino acid residues like cysteine. Unusual synonymous codon and amino acid usage in highly expressed genes can reflect a balance between translational selection and other factors. A correlation of gene expression level with synonymous codon or amino acid usage is emphasized in genes down-regulated in symbiont-bearing cells compared to symbiont-free cells. Our results imply that the selection is associated with P. bursaria-Chlorella symbiosis. PMID:26341535

  20. Analysis of amino acids network based on distance matrix

    NASA Astrophysics Data System (ADS)

    Ali, Tazid; Akhtar, Adil; Gohain, Nisha

    2016-06-01

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

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

    PubMed

    Hu, C; Wang, J

    2016-01-01

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

  2. Amino acid metabolism and protein synthesis in malarial parasites*

    PubMed Central

    Sherman, I. W.

    1977-01-01

    Malaria-infected red cells and free parasites have limited capabilities for the biosynthesis of amino acids. Therefore, the principal amino acid sources for parasite protein synthesis are the plasma free amino acids and host cell haemoglobin. Infected cells and plasmodia incorporate exogenously supplied amino acids into protein. However, the hypothesis that amino acid utilization (from an external source) is related to availability of that amino acid in haemoglobin is without universal support: it is true for isoleucine and for Plasmodium knowlesi and P. falciparum, but not for methionine, cysteine, and other amino acids, and it does not apply to P. lophurae. More by default than by direct evidence, haemoglobin is believed to be the main amino acid reservoir available to the intraerythrocytic plasmodium. Haemoglobin, ingested via the cytostome, is held in food vacuoles where auto-oxidation takes place. As a consequence, haem is released and accumulates in the vacuole as particulate haemozoin (= malaria pigment). Current evidence favours the view that haemozoin is mainly haematin. Acid and alkaline proteases (identified in crude extracts from mammalian and avian malarias) are presumably secreted directly into the food vacuole. They then digest the denatured globin and the resulting amino acids are incorporated into parasite protein. Cell-free protein synthesizing systems have been developed using P. knowlesi and P. lophurae ribosomes. In the main these systems are typically eukaryotic. Studies of amino acid metabolism are exceedingly limited. Arginine, lysine, methionine, and proline are incorporated into protein, whereas glutamic acid is metabolized via an NADP-specific glutamic dehydrogenase. Glutamate oxidation generates NADPH and auxiliary energy (in the form of α-ketoglutarate). The role of red cell glutathione in the economy of the parasite remains obscure. Important goals for future research should be: quantitative assessment of the relative importance of

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

    PubMed

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

    2013-07-28

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

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

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... diazotized 2,5-diethoxybenzenamine. (a) Chemical substance and significant new uses subject to reporting. (1... 40 Protection of Environment 31 2011-07-01 2011-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid...

  5. 40 CFR 721.1705 - Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid...

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... diazotized 2,5-diethoxybenzenamine. (a) Chemical substance and significant new uses subject to reporting. (1... 40 Protection of Environment 30 2010-07-01 2010-07-01 false Benzoic acid, 3-amino-, diazotized, coupled with 6-amino-4-hydroxy-2-naphthalenesulfonic acid, diazotized, (3-aminophenyl)phosphonic acid...

  6. Trifluoroselenomethionine: A New Unnatural Amino Acid.

    PubMed

    Block, Eric; Booker, Squire J; Flores-Penalba, Sonia; George, Graham N; Gundala, Sivaji; Landgraf, Bradley J; Liu, Jun; Lodge, Stephene N; Pushie, M Jake; Rozovsky, Sharon; Vattekkatte, Abith; Yaghi, Rama; Zeng, Huawei

    2016-09-15

    Trifluoroselenomethionine (TFSeM), a new unnatural amino acid, was synthesized in seven steps from N-(tert-butoxycarbonyl)-l-aspartic acid tert-butyl ester. TFSeM shows enhanced methioninase-induced cytotoxicity, relative to selenomethionine (SeM), toward HCT-116 cells derived from human colon cancer. Mechanistic explanations for this enhanced activity are computationally and experimentally examined. Comparison of TFSeM and SeM by selenium EXAFS and DFT calculations showed them to be spectroscopically and structurally very similar. Nonetheless, when two different variants of the protein GB1 were expressed in an Escherichia coli methionine auxotroph cell line in the presence of TFSeM and methionine (Met) in a 9:1 molar ratio, it was found that, surprisingly, 85 % of the proteins contained SeM residues, even though no SeM had been added, thus implying loss of the trifluoromethyl group from TFSeM. The transformation of TFSeM into SeM is enzymatically catalyzed by E. coli extracts, but TFSeM is not a substrate of E. coli methionine adenosyltransferase. PMID:27383291

  7. Amino acid fermentation at the origin of the genetic code

    PubMed Central

    2012-01-01

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

  8. Mechanisms for stimulation of rat anterior pituitary cells by arginine and other amino acids.

    PubMed Central

    Villalobos, C; Núñez, L; García-Sancho, J

    1997-01-01

    1. Arginine and other amino acids are secretagogues for growth hormone and prolactin in the intact animal, but the mechanism of action is unclear. We have studied the effects of amino acids on cytosolic free calcium concentration ([Ca2+]i) in single rat anterior pituitary (AP) cells. Arginine elicited a large increase of [Ca2+]i) in about 40% of all the AP cells, suggesting that amino acids may modulate hormone secretion by acting directly on the pituitary. 2. Cell typing by immunofluorescence of the hormone the cells store showed that the arginine-sensitive cells are distributed uniformly within all the five AP cell types. The arginine-sensitive cells overlapped closely with the subpopulation of cells sensitive to thyrotrophin-releasing hormone. 3. Other cationic as well as several neutral (dipolar) amino acids had the same effect as arginine. The increase of [Ca2+]i was dependent on extracellular Ca2+ and blocked by dihydropyridine, suggesting that it is due to Ca2+ influx through L-type voltage-gated Ca2+ channels. The [Ca2+]i increase was also blocked by removal of extracellular Na+ but not by tetrodotoxin. The substrate specificity for stimulation of AP cells resembled closely that of the amino acid transport system B0+. We propose that electrogenic amino acid influx through this pathway depolarizes the plasma membrane with the subsequent activation of voltage-gated Ca2+ channels and Ca2+ entry. 4. Amino acids also stimulated prolactin secretion in vitro with a similar substrate specificity to that found for the [Ca2+]i increase. Existing data on the stimulation of secretion of other hormones by amino acids suggest that a similar mechanism could apply to other endocrine glands. PMID:9263921

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

    SciTech Connect

    Standaert, Robert F; Park, Dr Seung Bum

    2006-01-01

    Photoisomerizable amino acids provide a direct avenue to the experimental manipulation of bioactive polypeptides, potentially allowing real-time, remote control of biological systems and enabling useful applications in nanobiotechnology. Herein, we report a new class of photoisomerizable amino acids intended to cause pronounced expansion and contraction in the polypeptide backbone, i.e., to be photoelastic. These compounds, termed Abc amino acids, employ a photoisomerizable azobiphenyl chromophore to control the relative disposition of aminomethyl and carboxyl substituents. Molecular modeling of nine Abc isomers led to the identification of one with particularly attractive properties, including the ability to induce contractions up to 13A 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. Influence of glyphosate on amino acid composition of Egyptian broomrape.

    PubMed

    Nandula, V K; Westwood, J H; Foster, J G; Foy, C L

    2001-03-01

    The parasitic plant broomrape is entirely dependent on its host for reduced carbon and nitrogen and is also susceptible to inhibition by glyphosate that is translocated to the parasite through a host. Studies were conducted to examine the effect of broomrape parasitism on amino acid concentrations of two hosts: common vetch that is tolerant of low levels of glyphosate and oilseed rape that has been genetically engineered for glyphosate resistance. The influence of glyphosate on the amino acid content of broomrape and the two hosts was also examined. Amino acid concentrations in leaves and roots of parasitized common vetch plants were generally similar to those of the corresponding tissues of nonparasitized plants. Amino acid concentrations in broomrape were lower than those of the parasitized common vetch root. For common vetch, glyphosate applied at rates that selectively inhibited broomrape growth did not alter individual amino acid concentrations in the leaves, but generally increased amino acid levels at 0.18 kg ha-1. Glyphosate application also increased the amino acid concentrations, with the exception of arginine, of broomrape growing on common vetch and did not generally influence concentrations in leaves or roots of common vetch. In oilseed rape, parasitization by broomrape generally led to higher amino acid concentrations in leaves but lower concentrations in roots of parasitized plants. Broomrape had higher amino acid concentrations than roots of the parasitized oilseed rape. Glyphosate applied at 0.25 and 0.5 kg ha-1 generally increased the amino acid concentrations in oilseed rape leaves, but the 0.75 kg ha-1 application caused the amino acid concentrations to decrease compared to those of untreated plants. In oilseed rape root the general trend was an increase in the concentration of amino acids at the two highest rates of glyphosate. Individual amino acid concentrations in broomrape attachments growing on oilseed rape were generally increased