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

Science.gov (United States)

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

2017-08-01

Amino acid composition of the grape berry at harvest is important for wine making. The present study investigates the complex interplay between tissue, cultivar and light conditions that determine berry amino acid content. Twenty amino acids were assessed in the berry skin and pulp of two grape cultivars (Gamay Noir and Gamay Fréaux), grown under either light exposure or cluster shading conditions. In all samples, cluster shading significantly reduced most amino acids, except gamma-aminobutyric acid (GABA) and phenylalanine. However, the magnitude of the decrease was stronger in the skin (67.0% decrease) than in the pulp (30.4%) and stronger in cv. Gamay Noir (69.7%) than in Gamay Fréaux (30.7%). Cluster shading also significantly modified amino acid composition by decreasing the proline content while increasing the GABA content. These results are of oenological interest for shaping the amino acid composition of the must and improving wine quality. Copyright © 2017 Elsevier Ltd. All rights reserved.

Studies on the distribution of radioactivity in the organism and rate of incorporation of radioactivity into the tissue proteins of monogastric animals after intravenous injection of tracer amino acids

International Nuclear Information System (INIS)

Simon, O.; Muenchmeyer, R.; Bergner, H.; Zebrowska, T.

1976-01-01

Radioactive amino acids ( 14 C leucine and 3 H lysine) were administrated to pigs by means of a catheter tube into the jugular vein. Subsequently, the time pattern of the distribution of the specific amino acid radioactivity was followed in the TCE soluble and TCE precipitable fractions of the blood plasma (TCE = trichloroacetic acid). Rats were injected 14 C into the portal vein. The animals were killed after incorporation periods of 2 to 60 minutes, and the levels of specific radioactivity were estimated in the TCE soluble and TCE precipitable fractions of the blood plasma, in the liver and in the skeletal muscles. The experimental results indicated that the specific radioactivity of the tracer amino acids and the rate of incorporation of radioactivity into tissue proteins were influenced by the size of the free amino acid pool within the range of distribution of the tracer. An estimation of the magnitude of the pool of free amino acids within the distribution range of the tracer can be obtained from the curve pattern for the decline of specific radioactivity of the corresponding free amino acid in the blood plasma. This pool exhibits a high rate of turnover. In all studies made to evaluate in vivo processes of protein synthesis using radioactive tracer amino acids it will be particularly important that consideration is given to the specific radioactivity of the amino acid in the precursor pool for protein synthesis. (author)

Residue-specific incorporation of noncanonical amino acids for protein engineering

NARCIS (Netherlands)

van Eldijk, Mark B.; van Hest, Jan C.M.; Lemke, E.A.

2018-01-01

The incorporation of noncanonical amino acids has given protein chemists access to an expanded repertoire of amino acids. This methodology has significantly broadened the scope of protein engineering allowing introduction of amino acids with non-native functionalities, such as bioorthogonal reactive

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

Science.gov (United States)

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

2014-05-20

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

Chloroformate derivatization for tracing the fate of Amino acids in cells and tissues by multiple stable isotope resolved metabolomics (mSIRM).

Science.gov (United States)

Yang, Ye; Fan, Teresa W-M; Lane, Andrew N; Higashi, Richard M

2017-07-11

applied this method to profile amino acids and their labeling patterns in 13 C and 2 H doubly labeled PC9 cell extracts, cancerous and non-cancerous tissue extracts from a lung cancer patient and their protein hydrolysates as well as plasma extracts from mice fed with a liquid diet containing 13 C 6 -glucose (Glc). The multi-element isotopologue distributions provided key insights into amino acid metabolism and intracellular pools in human lung cancer tissues in high detail. The 13 C labeling of Asp and Glu revealed de novo synthesis of these amino acids from 13 C 6 -Glc via the Krebs cycle, specifically the elevated level of 13 C 3 -labeled Asp and Glu in cancerous versus non-cancerous lung tissues was consistent with enhanced pyruvate carboxylation. In addition, tracking the fate of double tracers, ( 13 C 6 -Glc +  2 H 2 -Gly or 13 C 6 -Glc +  2 H 3 -Ser) in PC9 cells clearly resolved pools of Ser and Gly synthesized de novo from 13 C 6 -Glc ( 13 C 3 -Ser and 13 C 2 -Gly) versus Ser and Gly derived from external sources ( 2 H 3 -Ser, 2 H 2 -Gly). Moreover the complex 2 H labeling patterns of the latter were results of Ser and Gly exchange through active Ser-Gly one-carbon metabolic pathway in PC9 cells. Copyright © 2017 Elsevier B.V. All rights reserved.

The distribution of tritium among the amino acids of proteins obtained from mice exposed to tritiated water

International Nuclear Information System (INIS)

Commerford, S.L.; Carsten, A.L.; Cronkite, E.P.

1983-01-01

The distribution of tritium among the amino acids of serum proteins in mice chronically exposed to tritiated water was determined by ion exchange chromatography of the protein hydrolysate. The specific activity of nonexchangeable tritium in these amino acids relative to the specific activity of tritium in the tissue water of mice ranged from 0.04 for phenylalanine and threonine to 1.0 for glycine and alanine. Since tritium from tissue water can enter the nonexchangeable positions of amino acids only as the result of metabolic processing, the relative specific activity of tritium in each amino acid is an indicator of the extent of such processing. The tritium content of tyrosine and all the amino acids required in the diet for survival is quite low, except for histidine, and can be entirely accounted for by transamination or, in the case of methionine, by transmethylation. The tritium content of the other amino acids is too high to result from such minor processing and must reflect primarily the fraction synthesized de novo. The implications of these findings with respect to the radiobiological consequences of a diet containing tritiated proteins are discussed

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

Science.gov (United States)

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

2008-07-15

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

Measurement of L-[1-14C]leucine kinetics in splanchnic and leg tissues in humans. Effect of amino acid infusion

International Nuclear Information System (INIS)

Gelfand, R.A.; Glickman, M.G.; Castellino, P.; Louard, R.J.; DeFronzo, R.A.

1988-01-01

Although whole-body leucine flux is widely measured to study body protein turnover in humans, the contribution of specific tissues to the total-body measurement remains unknown. By combining the organ-balance technique with the systemic infusion of L-[1-14C]leucine, we quantitated leucine production and disposal by splanchnic and leg tissues and by the whole body, simultaneously, in six normal men before and during amino acid infusion. At steady state, disposal of arterial leucine by splanchnic and leg tissues was calculated from the percent extraction (E) of L-[1-14C]leucine counts: uptake = E x [Leu]a x flow. Tissue release of cold leucine (from protein turnover) into vein was calculated as the difference between leucine uptake and the net tissue leucine balance. In the postabsorptive state, despite substantial (P less than .01) extraction of L-[1-14C]leucine by splanchnic (23 +/- 1%) and leg (18 +/- 2%) tissues, net leucine balance across both tissue beds was small, indicating active simultaneous disposal and production of leucine at nearly equivalent rates. Splanchnic tissues accounted for approximately 50% of the measured total-body leucine flux. During amino acid infusion, the net leucine balance across splanchnic and leg tissues became positive, reflecting not only an increase in leucine uptake but also a marked suppression (by approximately 50%, P less than .02) of cold leucine release. This reduction in splanchnic and leg leucine release was indicated by a sharp decline in whole-body endogenous leucine flux

Both dietary supplementation with monosodium L-glutamate and fat modify circulating and tissue amino acid pools in growing pigs, but with little interactive effect.

Directory of Open Access Journals (Sweden)

Zemeng Feng

Full Text Available The Chinese population has undergone rapid transition to a high-fat diet. Furthermore, monosodium L-glutamate (MSG is widely used as a daily food additive in China. Little information is available on the effects of oral MSG and dietary fat supplementation on the amino acid balance in tissues. The present study aimed to determine the effects of both dietary fat and MSG on amino acid metabolism in growing pigs, and to assess any possible interactions between these two nutrients.Four iso-nitrogenous and iso-caloric diets (basal diet, high fat diet, basal diet with 3% MSG and high fat diet with 3% MSG were provided to growing pigs. The dietary supplementation with fat and MSG used alone and in combination were found to modify circulating and tissue amino acid pools in growing pigs. Both dietary fat and MSG modified the expression of gene related to amino acid transport in jejunum.Both dietary fat and MSG clearly influenced amino acid content in tissues but in different ways. Both dietary fat and MSG enhance the absorption of amino acids in jejunum. However, there was little interaction between the effects of dietary fat and MSG.

Isolation and complete amino acid sequence of human thymopoietin and splenin

International Nuclear Information System (INIS)

Audhya, T.; Schlesinger, D.H.; Goldstein, G.

1987-01-01

Human thymopoietin and splenin were isolated from human thymus and spleen, respectively, by monitoring tissue fractionation with a bovine thymopoietin RIA cross-reactive with human thymopoietin and splenin. Bovine thymopoietin and splenin are 49-amino acid polypeptides that differ by only 2 amino acids at positions 34 and 43; the change at position 34 in the active-site region changes the receptor specificities and biological activities. The complete amino acid sequences of purified human thymopoietin and splenin were determined and shown to be 48-amino acid polypeptides differing at four positions. Ten amino acids, constant within each species for thymopoietin and splenin, differ between the human and bovine polypeptides. The pentapeptide active side of thymopoietin (residues 32-36) is constant between the human and bovine thymopoietins, but position 34 in the active site of splenin has changed from glutamic acid in bovine splenin to alanine in human splenin, accounting for the biological activity of the human but not the bovine splenin on the human T-cell line MOLT-4

Genetic regulation by amino acids of specific membrane protein biosynthesis in isolated rat hepatocytes

International Nuclear Information System (INIS)

Chiles, T.C.; Handlogten, M.E.; Kilberg, M.S.

1986-01-01

Rat Hepatocytes in primary culture were incubated in amino acid-free (AAF) medium or amino acid-supplemented (AAS) medium for 2-6 hr. The effect of amino acid starvation on the synthesis of specific membrane proteins was monitored by including 3 H-leucine during the incubation. A crude plasma membrane fraction was prepared and then analyzed by 2-D gel electrophoresis followed by fluorography. Amino acid deprivation caused an induction of the synthesis of 5 of the 30 proteins studied. The ratio (AAF/-AAS) of cpm incorporated into the remaining 25 proteins was 0.8 +/- 0.2, whereas the ratio for the 5 proteins that showed amino acid-dependent synthesis ranged from 1.5 to 2.5. The presence of 4 μM actinomycin in the AAF medium completely blocked the starvation-induced synthesis of the 5 proteins tested, but did not alter significantly the ratio of cpm incorporated into the other 25 proteins. Binding studies involving ConA suggested a plasma membrane location for the 5 proteins. The molecular weight values of the starvation-induced proteins are 70, 66, 66, 67, and 45kD. Surface-labelling of intact cells and preparation of antibodies against the 5 proteins will be used to establish the subcellular location and to describe the amino acid-dependent synthesis of each in more detail

Supplementation of branched-chain amino acids in protein-restricted diets modulates the expression levels of amino acid transporters and energy metabolism associated regulators in the adipose tissue of growing pigs

Directory of Open Access Journals (Sweden)

Yinghui Li

2016-03-01

Full Text Available This experiment was conducted to investigate the effects of branched-chain amino acids (BCAA supplemented in protein-restricted diets on the growth performance and the expression profile of amino acid transporters and energy metabolism related regulators in the white adipose tissue (WAT of different regional depots including dorsal subcutaneous adipose (DSA and abdominal subcutaneous adipose (ASA. A total of 24 crossbred barrows (7.40 ± 0.70 kg were randomly divided into 4 groups and were fed the following isocaloric diets for 33 days: 1 a recommended adequate protein diet (AP, 20% CP, as a positive control; 2 a low protein diet (LP, 17% CP; 3 the LP diet supplemented with BCAA (LP + B, 17% CP to reach the same level of the AP diet group; 4 the LP diet supplemented with 2 times the amount of BCAA (LP + 2B, 17% CP. The daily gain and daily feed intake of the LP diet group were the lowest among all the treatments (P  0.05. Moreover, BCAA supplementation down-regulated the expression levels of amino acid transporters including L-type amino acid transporter 1 and sodium-coupled neutral amino acid transporter 2 in DSA, but up-regulated the expression level of L-type amino acid transporter 4 in ASA (P < 0.05. Meanwhile, the energy sensor AMP-activated protein kinase α was activated in the DSA of pigs fed LP diet and in the ASA of the pigs fed AP or LP + 2B diets (P < 0.05. The mRNA expression profile of the selected mitochondrial component and mitochondrial biogenesis associated regulators in DSA and ASA also responded differently to dietary BCAA supplementation. These results suggested that the growth performance of growing pigs fed protein restricted diets supplemented with BCAA could catch up to that of the pigs fed AP diets. The results also partly demonstrated that the regulation mechanisms of BCAA are different in the adipose tissues of different depots.

Site specific incorporation of keto amino acids into proteins

Science.gov (United States)

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

2008-10-07

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

Serum Neuron-Specific Enolase, Biogenic Amino-Acids and Neurobehavioral Function in Lead-Exposed Workers from Lead-Acid Battery Manufacturing Process

OpenAIRE

K Ravibabu; T Barman; HR Rajmohan

2015-01-01

Background: The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). Methods: In a c...

Adipose Tissue Dysfunction and Altered Systemic Amino Acid Metabolism Are Associated with Non-Alcoholic Fatty Liver Disease.

Directory of Open Access Journals (Sweden)

Sulin Cheng

Full Text Available Fatty liver is a major cause of obesity-related morbidity and mortality. The aim of this study was to identify early metabolic alterations associated with liver fat accumulation in 50- to 55-year-old men (n = 49 and women (n = 52 with and without NAFLD.Hepatic fat content was measured using proton magnetic resonance spectroscopy (1H MRS. Serum samples were analyzed using a nuclear magnetic resonance (NMR metabolomics platform. Global gene expression profiles of adipose tissues and skeletal muscle were analyzed using Affymetrix microarrays and quantitative PCR. Muscle protein expression was analyzed by Western blot.Increased branched-chain amino acid (BCAA, aromatic amino acid (AAA and orosomucoid were associated with liver fat accumulation already in its early stage, independent of sex, obesity or insulin resistance (p<0.05 for all. Significant down-regulation of BCAA catabolism and fatty acid and energy metabolism was observed in the adipose tissue of the NAFLD group (p<0.001for all, whereas no aberrant gene expression in the skeletal muscle was found. Reduced BCAA catabolic activity was inversely associated with serum BCAA and liver fat content (p<0.05 for all.Liver fat accumulation, already in its early stage, is associated with increased serum branched-chain and aromatic amino acids. The observed associations of decreased BCAA catabolism activity, mitochondrial energy metabolism and serum BCAA concentration with liver fat content suggest that adipose tissue dysfunction may have a key role in the systemic nature of NAFLD pathogenesis.

On the Evolution of Specificity in Members of the Yeast Amino Acid Transporter Family as Parts of Specific Metabolic Pathways

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Christos Gournas

2018-05-01

Full Text Available In the recent years, molecular modeling and substrate docking, coupled with biochemical and genetic analyses have identified the substrate-binding residues of several amino acid transporters of the yeast amino acid transporter (YAT family. These consist of (a residues conserved across YATs that interact with the invariable part of amino acid substrates and (b variable residues that interact with the side chain of the amino acid substrate and thus define specificity. Secondary structure sequence alignments showed that the positions of these residues are conserved across YATs and could thus be used to predict the specificity of YATs. Here, we discuss the potential of combining molecular modeling and structural alignments with intra-species phylogenetic comparisons of transporters, in order to predict the function of uncharacterized members of the family. We additionally define some orphan branches which include transporters with potentially novel, and to be characterized specificities. In addition, we discuss the particular case of the highly specific l-proline transporter, PrnB, of Aspergillus nidulans, whose gene is part of a cluster of genes required for the utilization of proline as a carbon and/or nitrogen source. This clustering correlates with transcriptional regulation of these genes, potentially leading to the efficient coordination of the uptake of externally provided l-Pro via PrnB and its enzymatic degradation in the cell.

Partition of radiolabeled amino acids in detached wheat heads in culture

International Nuclear Information System (INIS)

Inwood, W.; Bernardin, J.

1990-01-01

The concentration of a particular amino acid supplied to a detached wheat head affected the ultimate distribution of that amino acid among the tissues of the head. Detached wheat heads (Triticum aestivum L. cv Cheyenne) were supplied with a pulse of [ 3 H]leucine in the culture medium and were chased with medium that contained glutamine as the sole nitrogen source. When the amount of radiolabel was held constant, an increasing concentration of unlabeled leucine in the pulse medium led to an increased partition of the radiolabel into the grain tissues of the head. When the concentration of unlabeled leucine was increased from zero to radiolabeled leucine was partitioned to endosperm tissue and twice as much to seedcoat tissues. An effect of amino acid concentration on radiolabel partition was also found for methionine and proline, but the effect was not as dramatic. These results suggest the existence of an amino acid transport system between the transpiration stream of the wheat head and the grain that exhibits cooperative kinetics or amino acid activation

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

Science.gov (United States)

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

2011-02-01

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

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

Science.gov (United States)

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

2004-01-01

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

Comparison of amino acids interaction with gold nanoparticle.

Science.gov (United States)

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

2014-04-01

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

Amino acid analogs for tumor imaging

International Nuclear Information System (INIS)

Goodman, M.M.; Shoup, T.

1998-01-01

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 [ 18 F]-1-amino-3-fluorocyclobutane-1-carboxylic acid (FACBC). In another aspect, the invention features pharmaceutical compositions comprised of an α-amino acid moiety attached to either a four, five, or a six member carbon-chain ring. In addition, the invention features analogs of α-aminoisobutyric acid

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

Science.gov (United States)

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

2017-03-15

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

Effects of Arginine Supplementation on Amino Acid Profiles in Blood and Tissues in Fed and Overnight-Fasted Rats

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Milan Holecek

2016-04-01

Full Text Available Chronic arginine intake is believed to have favorable effects on the body. However, it might be hypothesized that excessive consumption of an individual amino acid exerts adverse effects on distribution and metabolism of other amino acids. We evaluated the effect of chronic intake of arginine on amino acid concentrations in blood plasma, liver, kidneys, and soleus and extensor digitorum longus muscles. Rats were fed a standard diet or a high-arginine diet (HAD for two months. Half of the animals in each group were sacrificed in the fed state, and the other half after fasting overnight. HAD increased blood plasma concentrations of urea, creatinine, arginine, and ornithine and decreased most other amino acids. Arginine and ornithine also increased in muscles and kidneys; an increase of lysine was observed in both muscle types. Methionine, phenylalanine, threonine, asparagine, glycine, serine, and taurine decreased in most tissues of HAD fed animals. Most of the effects of HAD disappeared after overnight fasting. It is concluded that (i enhanced dietary arginine intake alters distribution of almost all amino acids; and (ii to attain a better assessment of the effects of various nutritional interventions, an appropriate number of biochemical measurements must be performed in both postprandial and postabsorptive states.

Stereoselective synthesis of stable-isotope-labeled amino acids

Energy Technology Data Exchange (ETDEWEB)

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

1994-12-01

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

Stereoselective synthesis of stable-isotope-labeled amino acids

International Nuclear Information System (INIS)

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

1994-01-01

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 α-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

Site-specific incorporation of redox active amino acids into proteins

Science.gov (United States)

Alfonta, Lital [San Diego, CA; Schultz, Peter G [La Jolla, CA; Zhang, Zhiwen [San Diego, CA

2009-02-24

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

Site-specific incorporation of redox active amino acids into proteins

Energy Technology Data Exchange (ETDEWEB)

Alfonta, Lital; Schultz, Peter G.; Zhang, Zhiwen

2017-10-10

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

Alteration of putative amino acid levels and morphological findings in neural tissues of methylmercury-intoxicated mice

Energy Technology Data Exchange (ETDEWEB)

Hirayama, K.; Inouye, M.; Fujisaki, T.

1985-04-01

Methylmercury chloride was administered PO to male Kud:ddY mice at a dose of 5 mg/kg/day for 20 days. The contents of taurine, aspartate, glutamate, glycine, and ..gamma..-aminobutyric acid were determined in tissue and crude synaptosomal (P/sub 2/) fraction of cerebellum, cerebral cortex, and spinal cord of methylmercury-treated mice with or without ataxia. In the cerebellum of ataxic mice, increased levels of taurine and glycine were found in the tissue and P/sub 2/ fraction, and increased levels of glutamate were found in the P/sub 2/ fraction. In the cerebral cortex, the levels of ..gamma..-aminobutylic acid decreased in the tissue and in the P/sub 2/ fraction of ataxic mice, but increased levels were found in the tissue of non-ataxic mice. A decreased asparate level in the cerebral cortex of ataxic mice and an increased taurine level in the cerebral cortex of non-ataxic mice were also found. In the spinal cord of ataxic mice, taurine increased in the tissue and in the P/sub 2/ fraction. Glutamate level decreased in the spinal cord of ataxic mice, but increased in the P/sub 2/ fraction of non-ataxic mice. Increased glycine levels in the P/sub 2/ fraction of the spinal cord were also found in non-axtaxic mice. Histologically, some degenerative changes were demonstrated in the cerebral and cerebellar cortices of ataxic mice. Such changes were also present to a mild degree in non-ataxic mice. In conclusion, methylmercury treatment altered the levels of putative neurotransmitter amino acids in neutral tissue of mice. These alterations might be caused by specific neural cell dysfunction and could be related to the appearance of ataxia.

Free amino acids in spider hemolymph.

Science.gov (United States)

Tillinghast, Edward K; Townley, Mark A

2008-11-01

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

Transport of acidic amino acids by human jejunal brush-border membrane vesicles

International Nuclear Information System (INIS)

Rajendran, V.M.; Harig, J.M.; Adams, M.B.; Ramaswamy, K.

1987-01-01

This study characterizes the transport of radiolabeled acidic amino acids into brush-border membrane vesicles prepared from human jejunum. The uptakes of L-glutamic, L-aspartic, and D-aspartic acids were stimulated by a Na + gradient. Concentrative uptake (resulting in an overshoot phenomenon) of these dicarboxylic amino acids occurred when there was an outward K + gradient. In addition, increasing K + gradients resulted in enhanced uptake of L-glutamic acid. This K + requirement is somewhat specific as Rb + and Cs + could enhance uptake to a limited extent, whereas Li + and choline + showed no enhancement. The presence of a K + gradient did not affect the affinity of the carrier system for L-glutamic acid but it did increase the V/sub max/. The presence of extravesicular anions having differing membrane permeabilities did not altar L-glutamic acid uptake indicating an absence of an effect of membrane potential on the transport process. Finally, the human transport system for L-glutamic acid appears to be specific for acidic amino acids as demonstrated by inhibition studies. The studies demonstrate a transport system in human jejunum specific for acidic amino acids that is energized by an inward Na + gradient and an outward K + gradient

Amino acid compositions in heated carbonaceous chondrites and their compound-specific nitrogen isotopic ratios

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Chan, Queenie Hoi Shan; Chikaraishi, Yoshito; Takano, Yoshinori; Ogawa, Nanako O.; Ohkouchi, Naohiko

2016-01-01

A novel method has been developed for compound-specific nitrogen isotope compositions with an achiral column which was previously shown to offer high precision for nitrogen isotopic analysis. We applied the method to determine the amino acid contents and stable nitrogen isotopic compositions of individual amino acids from the thermally metamorphosed (above 500 °C) Antarctic carbonaceous chondrites Ivuna-like (CI)1 (or CI-like) Yamato (Y) 980115 and Ornans-like (CO)3.5 Allan Hills (ALH) A77003 with the use of gas chromatography/combustion/isotope ratio mass spectrometry. ALHA77003 was deprived of amino acids due to its extended thermal alteration history. Amino acids were unambiguously identified in Y-980115, and the δ15N values of selected amino acids (glycine +144.8 ‰; α-alanine +121.2 ‰) are clearly extraterrestrial. Y-980115 has experienced an extended period of aqueous alteration as indicated by the presence of hydrous mineral phases. It has also been exposed to at least one post-hydration short-lived thermal metamorphism. Glycine and alanine were possibly produced shortly after the accretion event of the asteroid parent body during the course of an extensive aqueous alteration event and have abstained from the short-term post-aqueous alteration heating due to the heterogeneity of the parent body composition and porosity. These carbonaceous chondrite samples are good analogs that offer important insights into the target asteroid Ryugu of the Hayabusa-2 mission, which is a C-type asteroid likely composed of heterogeneous materials including hydrated and dehydrated minerals.

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

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Rafael Pernil

2015-04-01

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

Plasma amino acids

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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 ...

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

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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.

Use of Shark Dental Protein to Estimate Trophic Position via Amino Acid Compound-Specific Isotope Analysis

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Hayes, M.; Herbert, G.; Ellis, G.

2017-12-01

The diets of apex predators such as sharks are expected to change in response to overfishing of their mesopredator prey, but pre-anthropogenic baselines necessary to test for such changes are lacking. Stable isotope analysis (SIA) of soft tissues is commonly used to study diets in animals based on the bioaccumulation of heavier isotopes of carbon and nitrogen with increasing trophic level. In specimens representing pre-anthropogenic baselines, however, a modified SIA approach is needed to deal with taphonomic challenges, such as loss of soft tissues or selective loss of less stable amino acids (AAs) in other sources of organic compounds (e.g., teeth or bone) which can alter bulk isotope values. These challenges can be overcome with a compound-specific isotope analysis of individual AAs (AA-CSIA), but this first requires a thorough understanding of trophic enrichment factors for individual AAs within biomineralized tissues. In this study, we compare dental and muscle proteins of individual sharks via AA-CSIA to determine how trophic position is recorded within teeth and whether that information differs from that obtained from soft tissues. If skeletal organics reliably record information about shark ecology, then archaeological and perhaps paleontological specimens can be used to investigate pre-anthropogenic ecosystems. Preliminary experiments show that the commonly used glutamic acid/phenylalanine AA pairing may not be useful for establishing trophic position from dental proteins, but that estimated trophic position determined from alternate AA pairs are comparable to those from muscle tissue within the same species.

Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid

International Nuclear Information System (INIS)

Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang

2016-01-01

In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu"2"+ through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10"−"3–10"−"6 M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. - Highlights: • A novel task-specific ionic liquid functionalized gold nanoparticle was successfully prepared. • This material was successfully applied to recognizing five amino acids with Cu(II) through distinctive color changes. • The proposed strategy was successfully used to analyze the histidine in real samples.

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

Science.gov (United States)

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

2009-07-01

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

Amino acids

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

Amino Acid Patterns around Disulfide Bonds

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Brett Drury

2010-11-01

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

Amino acid properties conserved in molecular evolution.

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Witold R Rudnicki

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

New Functions and Potential Applications of Amino Acids.

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Uneyama, Hisayuki; Kobayashi, Hisamine; Tonouchi, Naoto

Currently, several types of amino acids are being produced and used worldwide. Nevertheless, several new functions of amino acids have been recently discovered that could result in other applications. For example, oral stimulation by glutamate triggers the cephalic phase response to prepare for food digestion. Further, the stomach and intestines have specific glutamate-recognizing systems in their epithelial mucosa. Regarding clinical applications, addition of monosodium glutamate to the medicinal diet has been shown to markedly enhance gastric secretion in a vagus-dependent manner. Branched-chain amino acids (BCAAs) are the major components of muscles, and ingestion of BCAAs has been found to be effective for decreasing muscle pain. BCAAs are expected to be a solution for the serious issue of aging. Further, ingestion of specific amino acids could be beneficial. Glycine can be ingested for good night's sleep: glycine ingestion before bedtime significantly improved subjective sleep quality. Ingestion of alanine and glutamine effectively accelerates alcohol metabolism, and ingestion of cystine and theanine effectively prevents colds. Finally, amino acids could be used in a novel clinical diagnostic method: the balance of amino acids in the blood could be an indicator of the risk of diseases such as cancer. These newly discovered functions of amino acids are expected to contribute to the resolution of various issues.

Review: Taurine: A “very essential” amino acid

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Shen, Wen

2012-01-01

Taurine is an organic osmolyte involved in cell volume regulation, and provides a substrate for the formation of bile salts. It plays a role in the modulation of intracellular free calcium concentration, and although it is one of the few amino acids not incorporated into proteins, taurine is one of the most abundant amino acids in the brain, retina, muscle tissue, and organs throughout the body. Taurine serves a wide variety of functions in the central nervous system, from development to cytoprotection, and taurine deficiency is associated with cardiomyopathy, renal dysfunction, developmental abnormalities, and severe damage to retinal neurons. All ocular tissues contain taurine, and quantitative analysis of ocular tissue extracts of the rat eye revealed that taurine was the most abundant amino acid in the retina, vitreous, lens, cornea, iris, and ciliary body. In the retina, taurine is critical for photoreceptor development and acts as a cytoprotectant against stress-related neuronal damage and other pathological conditions. Despite its many functional properties, however, the cellular and biochemical mechanisms mediating the actions of taurine are not fully known. Nevertheless, considering its broad distribution, its many cytoprotective attributes, and its functional significance in cell development, nutrition, and survival, taurine is undoubtedly one of the most essential substances in the body. Interestingly, taurine satisfies many of the criteria considered essential for inclusion in the inventory of neurotransmitters, but evidence of a taurine-specific receptor has yet to be identified in the vertebrate nervous system. In this report, we present a broad overview of the functional properties of taurine, some of the consequences of taurine deficiency, and the results of studies in animal models suggesting that taurine may play a therapeutic role in the management of epilepsy and diabetes. PMID:23170060

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

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

2009-01-01

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

Specific ionic effect for simple and rapid colorimetric sensing assays of amino acids using gold nanoparticles modified with task-specific ionic liquid

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Wu, Datong; Cai, Pengfei; Tao, Zhihao; Pan, Yuanjiang, E-mail: panyuanjiang@zju.edu.cn

2016-01-01

In this study, a novel task-specific ionic liquid functionalized gold nanoparticle (TSIL-GNP) was successfully prepared and applied in the recognition of amino acids. Particularly, the surface of GNP was modified with the ionic liquid containing carbamido and ester group via thiol, which was characterized by Fourier transform infrared spectroscopy (FTIR) and transmission electron microscopy (TEM). The stability of this material in aqueous solution improves apparently and can remain unchanged for more than three months. The effect of pH was also discussed in this study. Attractive ionic interaction would effectively weaken intensity of the covalent coupling between the metal ion and the functional groups of amino acids. Thus, TSIL-GNP was successfully applied to recognizing serine, aspartic acid, lysine, arginine, and histidine in the presence of Cu{sup 2+} through distinctive color changes. Suspension would be generated once a spot of cysteine was added into the GNPs solution. Results indicated that it had a good linear relationship between extinction coefficients and concentration of amino acids in a wide range of 10{sup −3}–10{sup −6} M. Moreover, the proposed strategy was successfully used to analyze the histidine in urinary samples. In brief, TSIL-GNP is a suitable substrate for discrimination of five amino acids in a rapid and simple way without sophisticated instruments. - Highlights: • A novel task-specific ionic liquid functionalized gold nanoparticle was successfully prepared. • This material was successfully applied to recognizing five amino acids with Cu(II) through distinctive color changes. • The proposed strategy was successfully used to analyze the histidine in real samples.

Reactions of tritium atoms with amino acids, deuterated amino acids and mixtures of amino acids. Additivity property and isotope effect

International Nuclear Information System (INIS)

Badun, G.A.; Filatov, Eh.S.

1988-01-01

Interaction of tritium atoms with glycine (1) and leucine (2) amino acids, deuterated amino acids, their mixtures and glycylleucine (3) peptide in the 77-300 K temperature range is studied in isothermal and gradient regimes. Tagged amino acids were separated from targets after conducting the reaction. At T 150 K are associated with intermolecular transmission of free valence in the mixture of amino acids. Regularities of the reaction found for the mixture of amino acids are conserved for (3) as well, i.e. the peptide bond does not essentially affect the reaction of isotopic exchange conditioned by atomic tritium

Comparative analysis of amino acids and amino-acid derivatives in protein crystallization

International Nuclear Information System (INIS)

Ito, Len; Shiraki, Kentaro; Yamaguchi, Hiroshi

2010-01-01

New types of aggregation suppressors, such as amino acids and their derivatives, were focused on as fourth-component additives. Data were obtained that indicated that the additives promote protein crystallization. Optimal conditions for protein crystallization are difficult to determine because proteins tend to aggregate in saturated solutions. This study comprehensively evaluates amino acids and amino-acid derivatives as additives for crystallization. This fourth component of the solution increases the probability of crystallization of hen egg-white lysozyme in various precipitants owing to a decrease in aggregation. These results suggest that the addition of certain types of amino acids and amino-acid derivatives, such as Arg, Lys and esterified and amidated amino acids, is a simple method of improving the success rate of protein crystallization

Distribution of Amino Acids in Lunar Regolith

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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.

Cutting back on the essentials: Can manipulating intake of specific amino acids modulate health and lifespan?

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Brown-Borg, Holly M; Buffenstein, Rochelle

2017-10-01

With few exceptions, nutritional and dietary interventions generally impact upon both old-age quality of life and longevity. The life prolonging effects, commonly observed with dietary restriction reportedly are linked to alterations in protein intake and specifically limiting the dietary intake of certain essential amino acids. There is however a paucity of data methodically evaluating the various essential amino acids on health- and lifespan and the mechanisms involved. Rodent diets containing either lower methionine content, or tryptophan, than that found in commercially available chow, appear to elicit beneficial effects. It is unclear whether all of these favorable effects associated with restricted intake of methionine and tryptophan are due to their specific unique properties or if restriction of other essential amino acids, or proteins in general, may produce similar results. Considerably more work remains to be done to elucidate the mechanisms by which limiting these vital molecules may delay the onset of age-associated diseases and improve quality of life at older ages. Copyright © 2016 Elsevier B.V. All rights reserved.

Compound-Specific Isotopic Analysis of Meteoritic Amino Acids as a Tool for Evaluating Potential Formation Pathways

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

2012-01-01

Measurements of stable hydrogen, carbon, and nitrogen isotopic ratios (delta D, delta C-13, delta N-15) of organic compounds can reveal information about their origin and formation pathways. Several formation mechanisms and environments have been postulated for the amino acids detected in carbonaceous chondrites. As each proposed mechanism utilizes different precursor molecules, the isotopic signatures of the resulting amino acids may point towards the most likely of these proposed pathways. The technique of gas chromatography coupled with mass spectrometry and isotope ratio mass spectrometry provides compound-specific structural and isotopic information from a single splitless injection, enhancing the amount of information gained from small amounts of precious samples such as carbonaceous chondrites. We have applied this technique to measure the compound-specific C, N, and H isotopic ratios of amino acids from seven CM and CR carbonaceous chondrites. We are using these measurements to evaluate predictions of expected isotopic enrichments from potential formation pathways and environments, leading to a better understanding of the origin of these compounds.

Effects of hippocampal high-frequency electrical stimulation in memory formation and their association with amino acid tissue content and release in normal rats.

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Luna-Munguía, Hiram; Meneses, Alfredo; Peña-Ortega, Fernando; Gaona, Andres; Rocha, Luisa

2012-01-01

Hippocampal high frequency electrical stimulation (HFS) at 130 Hz has been proposed as a therapeutical strategy to control neurological disorders such as intractable temporal lobe epilepsy (TLE). This study was carried out to determine the effects of hippocampal HFS on the memory process and the probable involvement of amino acids. Using the autoshaping task, we found that animals receiving hippocampal HFS showed augmented short-term, but not long-term memory formation, an effect blocked by bicuculline pretreatment and associated with enhanced tissue levels of amino acids in hippocampus. In addition, microdialysis experiments revealed high extracellular levels of glutamate, aspartate, glycine, taurine, and alanine during the application of hippocampal HFS. In contrast, GABA release augmented during HFS and remained elevated for more than 1 h after the stimulation was ended. HFS had minimal effects on glutamine release. The present results suggest that HFS has an activating effect on specific amino acids in normal hippocampus that may be involved in the enhanced short-term memory formation. These data further provide experimental support for the concept that hippocampus may be a promising target for focal stimulation to treat intractable seizures in humans. Copyright © 2010 Wiley Periodicals, Inc., Inc.

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

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

2017-02-08

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

Developmental changes in aspartate-family amino acid biosynthesis in pea chloroplasts

International Nuclear Information System (INIS)

Mills, W.R.; Cato, L.W.; Stephens, B.W.; Reeves, M.

1990-01-01

Isolated chloroplasts are known to synthesize the asp-derived amino acids (ile, hse, lys and thr) from [ 14 C]asp (Mills et al, 1980, Plant Physiol. 65, 1166). Now, we have studied the influence of tissue age on essential amino acid biosynthesis in pea (Pisum sativum) plastids. Chloroplasts from the younger (third and fourth) leaves of 12 day old plants, were 2-3 times more active in synthesizing lys and thr from [ 14 C]asp than those from older (first or second) leaves. We also examined two key pathway enzymes (aspartate kinase and homoserine dehydrogenase); with each enzyme,a activity in younger leaves was about 2 times that in plastids from older tissue. Both lys- and thr-sensitive forms of aspartate kinase are known in plants; in agreement with earlier work, we found that lys-sensitive activity was about 4 times higher in the younger tissues, while the thr-sensitive activity changed little during development (Davies and Miflin, 1977, Plant Sci. Lett. 9, 323). Recently the role of aspartate kinase and homoserine dehydrogenase in controlling asp-family amino acid synthesis has been questioned (Giovanelli et al, 1989, Plant Physiol. 90, 1584); we hope that measurements of amino acid levels in chloroplasts as well as further enzyme studies will help us to better understand the regulation of asp-family amino acid synthesis

Studies on the distribution of radioactivity in the organism during constant intravenous infusion of tracer amino acids and on the calculation of the rate of tissue protein synthesis in rats

International Nuclear Information System (INIS)

Simon, O.; Bergner, H.; Wolf, E.

1978-01-01

Male wistar rats (100 p body weight) were infused into the tail vein with 14 C-leucine and 14 C-lysine simultaneously for 0.5; 1.0; 2.0; 3.0; 4.5; 6.0 and 7.0 hours. At the end of the infusion the specific radioactivity was determined of the free leucine and lysine in the blood plasma, liver, M. gastrocnemius, small intestine, and colon as well as of the protein-bound leucine and lysine. In all the tissues tested the specific radioactivity of the free amino acids attained a plateau during the 6-hour and 7-hour infusions. The rate constants for the increase were calculated for each organ tested. The two amino acids used are suitable for calculating the fractional rate of protein synthesis in tissues. The values of the fractional rate of protein synthesis calculated on the basis of the 6-hour and 7-hour infusions were: 54+-7.7%/day for the liver, 9.4+-1.2%/day for the muscles, 89+-12.2%/day for the small intestine, and 42+-5.9%/day for the colon. The simultaneous application of two tracer amino acids is recommendable for estimating the precursor pool of the protein synthesis and the more accurate calculation of the rate of protein synthesis. (author)

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

Science.gov (United States)

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

2014-09-01

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

Possible site-specific reagent for the general amino acid transport system of Saccharomyces cerevisiae.

Science.gov (United States)

Larimore, F S; Roon, R J

1978-02-07

The general amino acid transport system of Saccharomyces cerevisiae functions in the uptake of neutral, basic, and acidic amino acids. The amino acid analogue N-delta-chloroacetyl-L-ornithine (NCAO) has been tested as potential site specific reagent for this system. L-Tryptophan, which is transported exclusively by the general transport system, was used as a substrate. In the presence of glucose as an energy source, NCAO inhibited tryptophan transport competitively (Ki = 80 micrometer) during short time intervals (1-2 min), but adding 100 micrometer NCAO to a yeast cell suspension resulted in a time-dependent activation of tryptophan transport during the first 15 min of treatment. Following the activation a time-dependent decay of tryptophan transport activity occurred. Approximately 80% inactivation of the system was observed after 90 min. When a yeast cell suspension was treated with NCAO in the absence of an energy source, an 80% inactivation of tryptophan transport occurred in 90 min. The inactivation was noncompetitive (Ki congruent to 60 micrometer) and could not be reversed by the removal of the NCAO. Addition of a five-fold excess of L-lysine during NCAO treatment or prevented inactivation of tryptophan transport. Under parallel conditions of incubation, other closely related transport systems were not inhibited by NCAO.

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

Science.gov (United States)

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

2010-06-15

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

Distribution and Origin of Amino Acids in Lunar Regolith Samples

Science.gov (United States)

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

2015-01-01

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

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

DEFF Research Database (Denmark)

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

1988-01-01

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

Amino Acid Content of the Gamma Irradiated Cotton Leaf-Worm, Spodoptera Littoralis (Boisd.)

International Nuclear Information System (INIS)

Sobeiha, A.K.; Sallam, H.A.; El-Shall, S.S.A.

2000-01-01

The effects of gamma irradiation on amino acid content of the cotton leaf worm Spodoptera Littoralis was studied.The identified amino acids in the total body tissue of male moths were Theronine, Serine, Glutamic, Glycine, Alanine, Valine, Cystine, Methionine, Isoleucine, Leucine, Tyrosine, Phenylalanine, Lysine, Histidine and Arginine. The irradiation of full grown male pupae with doses 100,200 and 300 Gy decreased the total quantity of amino acids and the amount of most individual amino acids in male moths of P 1 or F 1 generations with some exceptions for Threonine, Alanine, Glycine, Serine, Valine, Cystine and Methionine which were increased.The effect of irradiation on amino acid content of the reproductive system tissues for each male or female were also studied.The results indicated that irradiation decreased the total quantity of amino acid content of both sexes by increasing the dose and males were more radiosensitive than females. Also, irradiation decreased the amount of individual amino acids in both sexes with certain exceptions, e.g. Alanine, Methionine and Tyrosine which increased in the reproductive system of male, and Methionine which increased by more than four times as control.The amino acid content was determined as well in F 1 egg progeny, which was produced from irradiated males Irradiation doses (100, 200 and 300 Gy) decreased the total quantity of amino acids, and all individual ones except Cystine.The greatest reduction (54.9% was observed with Lysine at 300 Gy as compared to control

Amino Acid Permeases and Virulence in Cryptococcus neoformans.

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Kevin Felipe Cruz Martho

Full Text Available Fungal opportunistic pathogens colonize various environments, from plants and wood to human and animal tissue. Regarding human pathogens, one great challenge during contrasting niche occupation is the adaptation to different conditions, such as temperature, osmolarity, salinity, pressure, oxidative stress and nutritional availability, which may constitute sources of stress that need to be tolerated and overcome. As an opportunistic pathogen, C. neoformans faces exactly these situations during the transition from the environment to the human host, encountering nutritional constraints. Our previous and current research on amino acid biosynthetic pathways indicates that amino acid permeases are regulated by the presence of the amino acids, nitrogen and temperature. Saccharomyces cerevisiae and Candida albicans have twenty-four and twenty-seven genes encoding amino acid permeases, respectively; conversely, they are scarce in number in Basidiomycetes (C. neoformans, Coprinopsis cinerea and Ustilago maydis, where nine to ten permease genes can be found depending on the species. In this study, we have demonstrated that two amino acid permeases are essential for virulence in C. neoformans. Our data showed that C. neoformans uses two global and redundant amino acid permeases, Aap4 and Aap5 to respond correctly to thermal and oxidative stress. Double deletion of these permeases causes growth arrest in C. neoformans at 37°C and in the presence of hydrogen peroxide. The inability to uptake amino acid at a higher temperature and under oxidative stress also led to virulence attenuation in vivo. Our data showed that thermosensitivity caused by the lack of permeases Aap4 and Aap5 can be remedied by alkaline conditions (higher pH and salinity. Permeases Aap4 and Aap5 are also required during fluconazole stress and they are the target of the plant secondary metabolite eugenol, a potent antifungal inhibitor that targets amino acid permeases. In summary, our work

Incorporation of radioactive amino acids into protein in isolated rat hepatocytes

International Nuclear Information System (INIS)

Seglin, P.O.

1976-01-01

The incorporation of radioactivity from a 14 C-labelled amino acid mixture (algal protein hydrolysate) into protein in isolated rat hepatocytes has been studied. The incorporation rate declined with increasing cell concentration, an effect which could be explained by isotope consumption, partly (and largely) by isotope dilution due to the formation of non-labelled amino acids by the cells. At a high extracellular amino acid concentration, the rate of incorporation into protein became independent of cell concentration because the isotope dilution effect was now quantitatively insignificant. The time course of protein labelling at various cell concentrations correlated better with the intracellular than with the extracellular amino acid specific activity, suggesting that amino acids for protein synthesis were taken from an intracellular pool. With increasing extracellular amino acid concentrations, both the intracellular amino acid concentration, the intracellular radioactivity and the rate of incorporation into protein increased. Protein labelling exhibited a distinct time lag at high amino acid concentrations, presumable reflecting the time-dependent expansion of the intracellular amino acid pool. The gradual increase in the rate of protein labelling could be due either to an increased intracellular specific activity, or to a real stimulation of protein synthesis by amino acids, depending on whether the total intracellular amino acid pool or just the expandable compartment is the precursor pool for protein synthesis

Method Development for Efficient Incorporation of Unnatural Amino Acids

KAUST Repository

Harris, Paul D.

2014-04-01

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

Method Development for Efficient Incorporation of Unnatural Amino Acids

KAUST Repository

Harris, Paul D.

2014-01-01

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

Regional amino acid transport into brain during diabetes: Effect of plasma amino acids

International Nuclear Information System (INIS)

Mans, A.M.; DeJoseph, M.R.; Davis, D.W.; Hawkins, R.A.

1987-01-01

Transport of phenylalanine and lysine into the brain was measured in 4-wk streptozotocin-diabetic rats to assess the effect on the neutral and basic amino acid transport systems at the blood-brain barrier. Amino acid concentrations in plasma and brain were also measured. Regional permeability-times-surface area (PS) products and influx were determined using a continuous infusion method and quantitative autoradiography. The PS of phenylalanine was decreased by an average of 40% throughout the entire brain. Influx was depressed by 35%. The PS of lysine was increased by an average of 44%, but the influx was decreased by 27%. Several plasma neutral amino acids (branched chain) were increased, whereas all basic amino acids were decreased. Brain tryptophan, phenylalanine, tyrosine, methionine, and lysine contents were markedly decreased. The transport changes were almost entirely accounted for by the alterations in the concentrations of the plasma amino acids that compete for the neutral and basic amino acid carriers. The reduced influx could be responsible for the low brain content of some essential amino acids, with possibly deleterious consequences for brain functions

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

International Nuclear Information System (INIS)

Rosenspire, K.C.; Gelbard, A.S.

1986-01-01

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

substantiation of the standards for tritium amino acids intake by human organism

International Nuclear Information System (INIS)

Zhesko, T.V.; Balonov, M.I.

1984-01-01

Calculated values of β-irradiation tissue doses of bound tritium and tritium oxide absorbed by animals treated with different amino acids are given. The obtained dose values are compared with tritium water doses. The data obtained in animal studies are extrapolated to man in order to determine the dose equivalent to the incorporated 3 H-amino acids dose. It is assumed that the dose equivalent to 3 H-amino acids radiation is three times as high as the equivalent amount of tritium oxide. 9 mCi/yr is established as the maximum allowable blood intake of 3 H-amino acids. Due to their metabolic characteristics, air permissible concentrations of 3 H-amino acids and tritium oxide have approximately the same values. The value of 30 nCi/cm 2 is recommended as a standard for work clothing contamination with 3 H-amino acids

LAT1 acts as a crucial transporter of amino acids in human thymic carcinoma cells

Directory of Open Access Journals (Sweden)

Keitaro Hayashi

2016-11-01

Full Text Available L-type amino acid transporter 1 (LAT1, SLC7A5 incorporates essential amino acids into cells. Recent studies have shown that LAT1 is a predominant transporter in various human cancers. However, the function of LAT1 in thymic carcinoma remains unknown. Here we demonstrate that LAT1 is a critical transporter for human thymic carcinoma cells. LAT1 was strongly expressed in human thymic carcinoma tissues. LAT1-specific inhibitor significantly suppressed leucine uptake and growth of Ty82 human thymic carcinoma cell lines, suggesting that thymic carcinoma takes advantage of LAT1 as a quality transporter and that LAT1-specific inhibitor might be clinically beneficial in therapy for thymic carcinoma.

Specificity of the Acute Tryptophan and Tyrosine Plus Phenylalanine Depletion and Loading Tests I. Review of Biochemical Aspects and Poor Specificity of Current Amino Acid Formulations

Directory of Open Access Journals (Sweden)

Abdulla A.-B. Badawy

2010-06-01

Full Text Available The acute tryptophan or tyrosine plus phenylalanine depletion and loading tests are powerful tools for studying the roles of serotonin, dopamine and noradrenaline in normal subjects and those with behavioural disorders. The current amino acid formulations for these tests, however, are associated with undesirable decreases in ratios of tryptophan or tyrosine plus phenylalanine to competing amino acids resulting in loss of specificity. This could confound biochemical and behavioural findings. Compositions of current formulations are reviewed, the biochemical principles underpinning the tests are revisited and examples of unintended changes in the above ratios and their impact on monoamine function and behaviour will be demonstrated from data in the literature. The presence of excessive amounts of the 3 branched-chain amino acids Leu, Ile and Val is responsible for these unintended decreases and the consequent loss of specificity. Strategies for enhancing the specificity of the different formulations are proposed.

Specificity of the Acute Tryptophan and Tyrosine plus Phenylalanine Depletion and Loading Tests I. Review of Biochemical Aspects and Poor Specificity of Current Amino Acid Formulations

Directory of Open Access Journals (Sweden)

Abdulla A.-B. Badawy

2010-01-01

Full Text Available The acute tryptophan or tyrosine plus phenylalanine depletion and loading tests are powerful tools for studying the roles of serotonin, dopamine and noradrenaline in normal subjects and those with behavioural disorders. The current amino acid formulations for these tests, however, are associated with undesirable decreases in ratios of tryptophan or tyrosine plus phenylalanine to competing amino acids resulting in loss of specificity. This could confound biochemical and behavioural findings. Compositions of current formulations are reviewed, the biochemical principles underpinning the tests are revisited and examples of unintended changes in the above ratios and their impact on monoamine function and behaviour will be demonstrated from data in the literature. The presence of excessive amounts of the 3 branched-chain amino acids Leu, Ile and Val is responsible for these unintended decreases and the consequent loss of specificity. Strategies for enhancing the specificity of the different formulations are proposed.

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

International Nuclear Information System (INIS)

Ito, Len; Kobayashi, Toyoaki; Shiraki, Kentaro; Yamaguchi, Hiroshi

2008-01-01

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

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

Energy Technology Data Exchange (ETDEWEB)

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

2008-05-01

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

Amino acids and proteins

NARCIS (Netherlands)

van Goudoever, Johannes B.; Vlaardingerbroek, Hester; van den Akker, Chris H.; de Groof, Femke; van der Schoor, Sophie R. D.

2014-01-01

Amino acids and protein are key factors for growth. The neonatal period requires the highest intake in life to meet the demands. Those demands include amino acids for growth, but proteins and amino acids also function as signalling molecules and function as neurotransmitters. Often the nutritional

Incorporation of 14C-amino acids proteins by abomasa from cow, buffalo calves and goat kid in vitro

International Nuclear Information System (INIS)

Angelo, I.A.; Ganguli, N.C.

1975-01-01

The capability of abomasal tissue to incorporate 14 C-amino acids in vitro into its tissue protein complex was demonstrated. The tissues from younger animals manifested higher activity. Amongst the species, abomasa from cow and buffalo calves exhibited higher incorporation efficiency than that observed with kid abomasum. Mucous membrane of abomasum was more potent in respect of the uptake of amino acid than the whole tissue. The impact of additives on the incorporation of amino acid showed distinct variation when tested with whole tissue and its mucous membrane fraction. (author)

Multi-omics approach to study the growth efficiency and amino acid metabolism in Lactococcus lactis at various specific growth rates

Directory of Open Access Journals (Sweden)

Arike Liisa

2011-02-01

Full Text Available Abstract Background Lactococcus lactis is recognised as a safe (GRAS microorganism and has hence gained interest in numerous biotechnological approaches. As it is fastidious for several amino acids, optimization of processes which involve this organism requires a thorough understanding of its metabolic regulations during multisubstrate growth. Results Using glucose limited continuous cultivations, specific growth rate dependent metabolism of L. lactis including utilization of amino acids was studied based on extracellular metabolome, global transcriptome and proteome analysis. A new growth medium was designed with reduced amino acid concentrations to increase precision of measurements of consumption of amino acids. Consumption patterns were calculated for all 20 amino acids and measured carbon balance showed good fit of the data at all growth rates studied. It was observed that metabolism of L. lactis became more efficient with rising specific growth rate in the range 0.10 - 0.60 h-1, indicated by 30% increase in biomass yield based on glucose consumption, 50% increase in efficiency of nitrogen use for biomass synthesis, and 40% reduction in energy spilling. The latter was realized by decrease in the overall product formation and higher efficiency of incorporation of amino acids into biomass. L. lactis global transcriptome and proteome profiles showed good correlation supporting the general idea of transcription level control of bacterial metabolism, but the data indicated that substrate transport systems together with lower part of glycolysis in L. lactis were presumably under allosteric control. Conclusions The current study demonstrates advantages of the usage of strictly controlled continuous cultivation methods combined with multi-omics approach for quantitative understanding of amino acid and energy metabolism of L. lactis which is a valuable new knowledge for development of balanced growth media, gene manipulations for desired product

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

OpenAIRE

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

2009-01-01

Urinary amino acid analysis is typically done by cation-exchange chromatography followed by post-column derivatization with ninhydrin and UV detection. This method lacks throughput and specificity. Two recently introduced stable isotope ratio mass spectrometric methods promise to overcome those shortcomings. Using two blinded sets of urine replicates and a certified amino acid standard, we compared the precision and accuracy of gas chromatography/mass spectrometry (GC-MS) and liquid chromatog...

The effect of insulin on amino acid incorporation into exocrine pancreatic cells of the rat

International Nuclear Information System (INIS)

Kramer, M.F.; Poort, C.

1975-01-01

The rate of incorporation of radioactive leucine per cell in the acinar pancreatic cells of the rat increases by 50 per cent within one hour after subcutaneous administration of insulin, an effect that lasts for at least one more hour. The rate of incorporation has been measured by quantitative radioautography and by determination of the radioactivity per μg DNA in TCA-precipitable material from tissue homogenates. The capacity for amino acid (leucine and lysine) incorporation as measured by incubating pancreatic fragments in vitro is not enhanced by insulin treatment of the rat in vivo during one or more hours. Insulin was found to lower the serum concentration of most amino acids significantly, leucine by 50 per cent. The apparent effect of insulin on the incorporation of radioactive leucine in vivo can be explained by the difference in the specific radioactivity of the circulating amino acid in the treated rats as compared to the untreated ones. A change in amino acid concentration in the serum may likewise be the explanation of the decrease in amino acid incorporation rate in alloxan diabetic rats. (orig./GSE) [de

Dependence of the metabolic fecal amino acids on the amino acid content of the feed. 1

International Nuclear Information System (INIS)

Krawielitzki, K.; Schadereit, R.; Voelker, T.; Reichel, K.

1981-01-01

The amount of metabolic fecal amino acids (MFAA) in dependence on the amino acid intake was determined for graded maize rations in 15 N-labelled rats and the part of labelled endogenous amino acids in feces was calculated by the isotope dilution method. The excretion of amino acids and MFAA in feces are described as functions of the amino acid intake for 17 amino acids and calculated regressively. For all 17 amino acids investigated, there was a more or less steep increase of MFAA according to an increasing amino acid intake. In contrast to N-free feeding, the MFAA increase to the 2- to 4.5-fold value in feeding with pure maize (16.5% crude protein). The thesis of the constancy of the excretion of MFAA can consequently be no longer maintained. The true digestibility according to the conventional method is, on an average of all amino acids, 7.3 units below ascertained according to the 15 N method. The limiting amino acids lysine and threonine revealed the greatest difference. Tryptophane as first limiting amino acid could not be determined. The true digestibility of nearly all amino acids ascertained for maize by the isotope method is above 90%. (author)

GC/MS-based profiling of amino acids and TCA cycle-related molecules in ulcerative colitis.

Science.gov (United States)

Ooi, Makoto; Nishiumi, Shin; Yoshie, Tomoo; Shiomi, Yuuki; Kohashi, Michitaka; Fukunaga, Ken; Nakamura, Shiro; Matsumoto, Takayuki; Hatano, Naoya; Shinohara, Masakazu; Irino, Yasuhiro; Takenawa, Tadaomi; Azuma, Takeshi; Yoshida, Masaru

2011-09-01

The roles that amino acids play in immunity and inflammation are well defined, and the relationship between inflammatory bowel disease (IBD) and certain amino acids has recently attracted attention. In this study, the levels of amino acids and trichloroacetic acid (TCA) cycle-related molecules in the colonic tissues and sera of patients with ulcerative colitis (UC) were profiled by gas chromatography/mass spectrometry (GC/MS), with the aim of evaluating whether the clinical state induced by UC leads to variations in the amino acid profile. Colonic biopsy samples from 22 UC patients were used, as well as serum samples from UC patients (n = 13), Crohn's disease (CD) patients (n = 21), and healthy volunteers (n = 17). In the GC/MS-based profiling of amino acids and TCA cycle-related molecules, lower levels of 16 amino acids and 5 TCA cycle-related molecules were observed in the colonic lesion tissues of the UC patients, and the serum profiles of amino acids and TCA cycle-related molecules of the UC patients were different from those of the CD patients and healthy volunteers. Our study raises the possibility that GC/MS-based profiling of amino acids and TCA cycle-related molecules is a useful early diagnostic tool for UC.

Potential use of carbon-11 labeled alpha-aminoisobutyric acid (AIB) as an in vivo tracer of amino acid uptake in differing metabolic states

International Nuclear Information System (INIS)

Conti, P.S.; Starnes, H.F.; Brennan, M.F.

1986-01-01

AIB has been used as a model amino acid for the evaluation of alanine-preferring amino acid transport. Hormonal factors and starvation alter the tissue distribution of amino acids, particularly in liver and muscle. With positron emission tomography and labeling of biochemical tracers with C-11, (t1/2=20.4 min), it is now possible to study amino acid kinetics in vivo using external imaging. In order to investigate the utility of C-11 AIB as an in vivo tracer of altered tissue metabolism, C-14 AIB was studied in groups of rats with either streptozotocin-induced diabetes, insulin-induced hypoglycemia or starvation. The data suggest an increased amino acid uptake in liver in starvation, an increased uptake in muscle in response to insulin and associated hypoglycemia and decreased transport in muscle in starvation, as seen by other investigators. These results suggest that C-11 AIB may be useful as an in vivo monitor of metabolic changes in body tissues

Tissue-specific expression of type IX collagen

International Nuclear Information System (INIS)

Nishimura, I.; Muragaki, Y.; Ninomiya, Y.; Olsen, B.R.; Hayashi, M.

1990-01-01

This paper reports on the tissue-specific expression of type IX collagen, a major component of cartilage fibrils. It contains molecules with three genetically distinct subunits. The subunits form three triple-helical (CO) domains separated by non-triple-helical (NC) sequences. One of the subunits in cartilage, α1(IX), contains a large amino-terminal globular domain, NC4, while a second subunit, α2(IX), contains a covalently attached chondroitin sulfate chain. The site of attachment for this chain is located within the non-triple-helical sequence NC3, which separates the amino-terminal and central triple-helical domains of the type IX molecules. The NC3 region is 5 amino acid residues longer in the α2(IX) chain than in the α1(IX) and α3(IX) chains. This may explain why type IX molecules tend to show a sharp angle in the NC3 region, and why monoclonal antibody molecules that are specific for the stub left after chondroitinase ABC digestion of the chondroitin sulfate side chain always are located on the outside of the angle

In vitro quantitative analysis of Salmonella typhimurium preference for amino acids secreted by human breast tumor

Science.gov (United States)

Choi, Eunpyo; Maeng, Bohee; Lee, Jae-hun; Chang, Hyung-kwan; Park, Jungyul

2016-12-01

Bacterial therapies have been paid significant attentions by their ability to penetrate deep into the solid tumor tissue and its propensity to naturally accumulate in tumors of living animals. Understanding the actual mechanism for bacteria to target the tumor is therapeutically crucial but is poorly understood. We hypothesized that amino acids released from the specific tumors induced bacteria to those tumors and the experiments for chemotactic response of bacteria toward the cancer secreting amino acids was then performed by using the diffusion based multiple chemical gradient generator constructed by in situ self-assembly of microspheres. The quantitative analysis was carried out by comparison of intensity using green fluorescent protein (GFP) tagged Salmonella typhimurium ( S. typhimurium) in the gradient generator, which showed the clear preference to the released amino acids, especially from breast cancer patients. The understanding chemotaxis toward the cancer secreting amino acids is essential for controlling S. typhimurium targeting in tumors and will allow for the development of bacterial therapies.

A class frequency mixture model that adjusts for site-specific amino acid frequencies and improves inference of protein phylogeny

Directory of Open Access Journals (Sweden)

Li Karen

2008-12-01

Full Text Available Abstract Background Widely used substitution models for proteins, such as the Jones-Taylor-Thornton (JTT or Whelan and Goldman (WAG models, are based on empirical amino acid interchange matrices estimated from databases of protein alignments that incorporate the average amino acid frequencies of the data set under examination (e.g JTT + F. Variation in the evolutionary process between sites is typically modelled by a rates-across-sites distribution such as the gamma (Γ distribution. However, sites in proteins also vary in the kinds of amino acid interchanges that are favoured, a feature that is ignored by standard empirical substitution matrices. Here we examine the degree to which the pattern of evolution at sites differs from that expected based on empirical amino acid substitution models and evaluate the impact of these deviations on phylogenetic estimation. Results We analyzed 21 large protein alignments with two statistical tests designed to detect deviation of site-specific amino acid distributions from data simulated under the standard empirical substitution model: JTT+ F + Γ. We found that the number of states at a given site is, on average, smaller and the frequencies of these states are less uniform than expected based on a JTT + F + Γ substitution model. With a four-taxon example, we show that phylogenetic estimation under the JTT + F + Γ model is seriously biased by a long-branch attraction artefact if the data are simulated under a model utilizing the observed site-specific amino acid frequencies from an alignment. Principal components analyses indicate the existence of at least four major site-specific frequency classes in these 21 protein alignments. Using a mixture model with these four separate classes of site-specific state frequencies plus a fifth class of global frequencies (the JTT + cF + Γ model, significant improvements in model fit for real data sets can be achieved. This simple mixture model also reduces the long

Changes in brain amino acid content induced by hyposmolar stress and energy deprivation.

Science.gov (United States)

Haugstad, T S; Valø, E T; Langmoen, I A

1995-12-01

The changes in endogenous amino acids in brain extracellular and intracellular compartments evoked by hyposmotic stress and energy deprivation were compared. Tissue content and release of ten amino acids were measured simultaneously in rat hippocampal slices by means of high performance liquid chromatography. Hyposmotic stress induced a large release of taurine (25568 pmol mg-1 protein), and a smaller release of glutamate, accompanied by an inverse change in tissue content. Adding mannitol to correct osmolarity, blocked these changes. Energy deprivation caused an increase in the release of all amino acids except glutamine. The release was particularly large for glutamate and GABA (31141 and 13282 pmol mg-1, respectively). The intracellular concentrations were generally reduced, but the total amount of the released amino acids increased In contrast to the effect seen during hyposmolar stress, mannitol enhanced the changes due to energy deprivation. The results show that hyposmolar stress and energy deprivation cause different content and release profiles, suggesting that the mechanisms involved in the two situations are either different or modulated in different ways. The intracellular amino acid depletion seen during energy deprivation shows that increased outward transport is probably a primary event, and increased amino acid formation likely secondary to this release.

In vivo synthesized 34S enriched amino acid standards for species specific isotope dilution of proteins

DEFF Research Database (Denmark)

Hermann, Gerrit; Moller, Laura Hyrup; Gammelgaard, Bente

2016-01-01

(ICP-MS) combined to anion exchange showed that very high concentrated spike material could be produced with [small mu ]mol amounts of proteinogenic sulfur containing amino acids per g cell dry weight. An enrichment of 34S to 96.3 +/- 0.4% (n = 3) and 98.5 +/- 0.4% (n = 3) for cysteic acid...... with the concept of species specific isotope dilution analysis (IDA). The method relies on the determination of the two sulfur containing amino acids, cysteine and methionine by sulfur speciation analysis and is hence applicable to any protein containing sulfur. In vivo synthesis using 34S as sulfur source...... and methionine sulfone, respectively, was assessed. The established IDA method was validated for the absolute quantification of commercially available lysozyme and ceruloplasmin standards including the calculation of a total combined uncertainty budget....

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

Science.gov (United States)

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

2015-08-01

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

Amino acid metabolism in plant leaf, 1

International Nuclear Information System (INIS)

Ito, Osamu; Kumazawa, Kikuo

1977-01-01

14C-labelled sodium bicarbonate and 15N-labelled ammonium sulfate were simultaneously vacuum-infiltrated into detached sunflower leaves, and the incorporation of 14C and 15N into free amino acids was chased during 60-min period in the light and in the dark. In the light, the 14C specific activity of aspartic acid, alanine, serine and glycine rapidly increased for 5 min and thereafter decreased. On the other hand, that of glutamic acid continued to increase slowly during the entire 60-min period. In the dark, aspartic acid most actively incorporated 14C. The difference of changes in 14C specific activity between glutamic acid and other amino acids was also observed in the dark as in the light. These results suggest that the carbon skeleton of glutamic acid is synthesized from aspartic acid, alanine, serine and glycine. 15N content of glutamine was the highest of all amino acids investigated in the light, and it was followed by glutamic acid, alanine, aspartic acid, serine and glycine, in this order. In the dark, 15N content of glutamic acid fell remarkably and was lower than that of alanine up to 5 min. From these 15N tracer experiments, it is suggested that the incorporation of ammonium into glutamic acid is strictly dependent on light and that alanine incorporates ammonium by the direct animation besides the transamination from glutamic acid. (auth.)

Studies on radiolysis of amino acids, (4)

International Nuclear Information System (INIS)

Oku, Tadatake

1978-01-01

In order to elucidate the effect of adding methionine on the loss of amino acid by γ-irradiation in amino acid mixture, because methionine is one of the most radio-sensitive in amino acids, the remaining amino acids in γ-irradiated aqueous solution of amino acid mixture were studied by determining the total amount of each remaining amino acid. The mixture of 18 amino acids which contains methionine and that of 17 amino acids without methionine were used. Amino acids and the irradiation products were determined with an automatic amino acid analyzer. The total amount of remaining amino acids in the irradiated solution of 18 amino acid mixture was more than that of 17 amino acid mixture. The order of the total amount of each remaining amino acid by low-dose irradiation was Gly>Ala>Asp>Glu>Val>Ser, Pro>Ile, Leu>Thr>Lys>Tyr>Arg>His>Phe>Try>Cys>Met. In case of the comparison of amino acids of same kinds, the total remaining amount of each amino acid in amino acid mixture was more than that of individually irradiated amino acid. The total remaining amounts of glycine, alanine and aspartic acid in irradiated 17 amino acid mixture resulted in slight increase. Ninhydrin positive products formed from 18 amino acid mixture irradiated with 2.640 x 10 3 rad were ammonia, methionine sulfoxide and DOPA of 1.34, 0.001 and 0.25 μmoles/ml of the irradiated solution, respectively. (Kobake, H.)

Post-duplication charge evolution of phosphoglucose isomerases in teleost fishes through weak selection on many amino acid sites

Directory of Open Access Journals (Sweden)

Sato Yukuto

2007-10-01

Full Text Available Abstract Background The partitioning of ancestral functions among duplicated genes by neutral evolution, or subfunctionalization, has been considered the primary process for the evolution of novel proteins (neofunctionalization. Nonetheless, how a subfunctionalized protein can evolve into a more adaptive protein is poorly understood, mainly due to the limitations of current analytical methods, which can detect only strong selection for amino acid substitutions involved in adaptive molecular evolution. In this study, we employed a comparative evolutionary approach to this question, focusing on differences in the structural properties of a protein, specifically the electric charge, encoded by fish-specific duplicated phosphoglucose isomerase (Pgi genes. Results Full-length cDNA cloning, RT-PCR based gene expression analyses, and comparative sequence analyses showed that after subfunctionalization with respect to the expression organ of duplicate Pgi genes, the net electric charge of the PGI-1 protein expressed mainly in internal tissues became more negative, and that of PGI-2 expressed mainly in muscular tissues became more positive. The difference in net protein charge was attributable not to specific amino acid sites but to the sum of various amino acid sites located on the surface of the PGI molecule. Conclusion This finding suggests that the surface charge evolution of PGI proteins was not driven by strong selection on individual amino acid sites leading to permanent fixation of a particular residue, but rather was driven by weak selection on a large number of amino acid sites and consequently by steady directional and/or purifying selection on the overall structural properties of the protein, which is derived from many modifiable sites. The mode of molecular evolution presented here may be relevant to various cases of adaptive modification in proteins, such as hydrophobic properties, molecular size, and electric charge.

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

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

Protein evolution via amino acid and codon elimination

DEFF Research Database (Denmark)

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

2010-01-01

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

The Role of Amino Acids in Gluconeogenesis in Lactating Ruminants

Energy Technology Data Exchange (ETDEWEB)

Black, A. L.; Egan, A. R.; Anand, R. S.; Chapman, T. E. [Department of Physiological Sciences, School of Veterinary Medicine, University of California, Davis, CA (United States)

1968-07-01

Gluconeogenesis has an important metabolic role in all animals, but it is especially important in ruminants because of the paucity of their alimentary glucose. Several amino acids give rise to glucogenic precursors during metabolism and thus dietary or body protein represents an important source of potential glucogenic material that the ruminant can utilize to manufacture the glucose required for its physiological functions. The role of various amino acids as glucose precursors has been evaluated in lactating ruminants by making a single intravenous injection of several different amino acids uniformly labelled with {sup 14}C and following, with time, the rate and extent of incorporation of {sup 14}C into the plasma glucose. The time interval after injecting each {sup 14}C-amino acid until the specific activity maximum occurred in plasma glucose was found to vary widely among the different amino acids. Thus, the maximum specific activity in plasma glucose occurred 6 min after injection of L-aspartate-{sup 14}C and 15 min after injection of L-glutamate- {sup 14}C, while for L-valine-{sup 14}C and L-arginine-{sup 14}C the maximum specific activity in plasma glucose did not occur until 45 and 90 min, respectively, had elapsed. After injection of L-serine and L-alanine there were several maxima in the glucose specific activity. These maxima occurred between 12 and 24 min after injection of serine and during the first 30 min after injection of alanine indicating that carbon from these amino acids becomes available for glucose synthesis along diverse pathways which have different delays. Although only a few amino acids have been studied, the experimental results obtained clearly suggest an important metabolic role for protein in ruminants which has previously not been recognized. It appears that amino acids, released from protein, are utilized by the animal in a fashion which results in a prolonged availability of glucogenic precursors so that the animal can form glucose

Effect of dietary protein and GABA on food intake, growth and tissue amino acids in cats.

Science.gov (United States)

Tews, J K; Rogers, Q R; Morris, J G; Harper, A E

1984-02-01

GABA at 5%, but not 3%, of a low protein diet depressed food intake and growth of kittens. Adaptation to high protein prevented these effects. When cats adapted to low or high protein were fed a meal containing GABA, plasma GABA concentration after 2 hr was 8-fold higher in the low than in the high protein group; clearance was almost complete within 6 hr. Concentrations of proline, branched-chain, other large neutral and basic (especially ornithine) amino acids increased more when cats were fed a high rather than a low protein meal; glycine decreased. At 6 hr, concentrations had consistently returned to initial levels only in the low protein group. Feeding the high protein diet ad lib increased tissue concentrations of threonine, proline and the branched-chain amino acids. Hepatic or renal GABA-aminotransferase activity was not altered in kittens fed the high protein diet. Kidney activity was 10-fold that of liver, which may contribute to the better tolerance of GABA by cats than by rats.

Radiotracer studies on the synthesis of prorennin and rennin using 14C-amino acids

International Nuclear Information System (INIS)

Angelo, I.A.; Ganguli, N.C.

1976-01-01

In vivo incorporation of 14 C-amino acids into the prorennin and rennin fractions of the abomasal tissue of the intact animal (i.e. calf) has been investigated by : (1) intravenous injection of the label and subsequent isolation of rennin and prorennin fractions from the excised abomasum and (2) feeding. of milk whey fortified with the label to a fistulated kid and subsequent processing of the abomasal juice for rennet extraction. Prorennin incorporates more radioactivity than rennin. This indicates that abomasal tissue uses blood amino acids for prorennin synthesis, but amino acids fed through dietary channels may not be used for rennin synthesis. (M.G.B.)

Investigation on the pancreatic and stomach secretion in pigs by means of continuous infusion of 14C-amino acids

International Nuclear Information System (INIS)

Simon, O.; Bergner, H.; Muenchmeyer, R.; Zebrowska, T.

1983-01-01

2 pigs received a barley-soya bean meal diet and another 2 a casein-wheat starch diet. The specific radioactivity (SR = dpm/μmol) of leucine and phenylalanine in the TCA soluble fraction of plasma and in the TCA soluble and TCA precipitable fractions of pancreatic juice and of digesta leaving the stomach was determined during 6 hours of intravenous infusion of 14 C-leucine and 14 C-phenylalanine. At the end of the infusion the SR of both amino acids in both fractions of several tissues was measured and used for calculations of the rate of tissue protein synthesis. The results are that mainly amino acids derived from the extracellular space were used for synthesis that the process of synthesis, concentration and secretion of secretory proteins requires in pigs 120 to 180 minutes, and that TCA soluble amino acids in pancreatic juice are not free amino acids per se, but originate from processing of presecretory proteins. In the duodenal digesta labelled proteins appeared 3 to 4 hours after the beginning of the infusion. Both, secretion of proteins by the pancreas and by the stomach seemed to be more stimulated after feeding the barley-soya diet than the casein-starch diet. Of all tissues, the SR of amino acids in proteins was highest in the pancreas. However, proteins secreted by the pancreas were 3 to 4 times higher labelled than those retained in the tissue. The range of the fractional rate of protein synthesis was calculated for the sections of the gastrointestinal tract, the liver and skeletal muscles and discussed with other findings. (author)

Evaluation of [1-11C]-α-aminoisobutyric acid for tumor detection and amino acid transport measurement: Spontaneous canine tumor studies

International Nuclear Information System (INIS)

Bigler, R.E.; Zanzonico, P.B.; Schmall, B.; Conti, P.S.; Dahl, J.R.; Rothman, L.; Sgouros, G.

1985-01-01

Alpha-aminoisobutyric acid (AIB) or α-methyl alanine, is a nonmetabolized amino acid treansported into cells particularly malignant cells, predominantly by the ''A'' amino acid transport system. Since it is not metabolized, [1- 11 C]-AIB can be used to quantify A-type amino acid transport into cells using a relatively simple compartmental model and quantitative imaging procedures (e.g. positron tomography). The tissue distribution of [1- 11 C]-AIB was determined in six dogs bearing spontaneous tumors, including lymphosarcoma, osteogenic sarcoma, mammary carcinoma, and adenocarcinoma. Quantitative imaging with tissue radioassay confirmation at necropsy showed poor to excellent tumor localization. However, in all cases the concentrations achieved appear adequate for amino acid transport measurement at known tumor locations. The observed low normal brain (due to blood-brain barrier exclusion) and high (relative to brain) tumor concentrations of [1- 11 C]-AIB suggest that this agent may prove effective for the early detection of human brain tumors. (orig.)

Laser-based optical activity detection of amino acids and proteins

Energy Technology Data Exchange (ETDEWEB)

Reitsma, B.H.

1987-08-01

The optical activity detector (OAD) for HPLC is a selective detector for optically active substances including amino acids and proteins. Four free amino acids were resolved using cation-exchange chromatography followed by detection with refractive index detector (RI) for proline and threonine and the OAD to an ultraviolet absorbance detector (uv) for tyrosine and phenylalanine. Amino acid detection by refractive index is not sensitive and uv absorbance detects only three amino acids. Derivatization of amino acids to make them detectable by uv absorbance enhances the applicability of OA/uv for the determination of enantiomeric ratios. The separation of 16 dansyl-L-amino acids by RP-HPLC with detection by OA/uv is illustrated. Calculation of the specific rotation of 22 dansyl-L-amino acids shows that derivatization enhances the OA detectability of some amino acids but degrades that of others. RP-HPLC of proteins is a rapidly developing technique. Several researchers have reported the detection of multiple peaks when a pure protein is subjected to HPLC under certain conditions. These multiple peaks have been determined to be different conformations of the same protein. Since proteins are optically active, OA is a suitable detector. The RP-HPLC separation of conformers of soybean trypsin inhibitor is illustrated. Detection by OA/uv provides insights from the chromatogram unavailable from uv absorbance detection alone. In addition, identification of impurities is simplified with OA/uv. Specific rotations of the separated protein fractions show no significant change accompanying change in conformation. 163 refs., 13 figs., 9 tabs.

Dependence of the metabolic fecal amino acids on the amino acid content of the feed. 2

International Nuclear Information System (INIS)

Krawielitzki, K.; Schadereit, R.; Voelker, T.; Reichel, K.

1982-01-01

In an experiment with 20 15 N-labelled growing rats the excretion of amino acids as well as of metabolic fecal amino acids were investigated after feeding of soybean oil meal as sole protein source. A low, yet statistically significant increase of the excretion of amino acids and metabolic fecal amino acids was ascertained in accordance with a growing quota of soybean oil meal in the ration. The true digestibility of amino acids ascertained according to conventional methods is above 90% and, under consideration of the increase of metabolic fecal amino acids, on the average increases by 3.5 digestibility units (1.4 to 6.2). (author)

Branched-chain amino acid supplementation during bed rest: effect on recovery

Science.gov (United States)

Stein, T. P.; Donaldson, M. R.; Leskiw, M. J.; Schluter, M. D.; Baggett, D. W.; Boden, G.

2003-01-01

Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P BCAA supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

tRNAs: cellular barcodes for amino acids

DEFF Research Database (Denmark)

Banerjee, Rajat; Chen, Shawn; Dare, Kiley

2010-01-01

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

Inhibitors of amino acids biosynthesis as antifungal agents.

Science.gov (United States)

Jastrzębowska, Kamila; Gabriel, Iwona

2015-02-01

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

Laser-based optical activity detection of amino acids and proteins

Energy Technology Data Exchange (ETDEWEB)

Reitsma, B.H.

1987-01-01

The optical activity detector (OAD) for HPLC is a selective detector for optically active substances including amino acids and proteins. This study illustrates the use of the OAD in three related areas. Section I illustrates the separation of four free amino acids using cation-exchange chromatography. Detection by coupling the OAD to a refractive index detector (RI) for proline and threonine and the OAD to an ultraviolet absorbance detector (UV) for tyrosine and phenylalanine allows the calculation of enantiomeric (D/L) ratios of these amino acids without physical separation. Specific rotations of these four amino acids are also reported. Section II illustrates the separation of 16 dansyl-L-amino acids by RP-HPLC with detection by OA/UV. Section III illustrates the RP-HPLC separation of conformers of soybean trypsin inhibitor. Detection by OA/UV provides insights from the chromatogram unavailable for UV absorbance detection alone. In addition, identification of impurities is simplified with OA/UV. Specific rotations of the separated protein fractions show no significant change accompanying change in conformation.

Biodistribution of [11C] methylaminoisobutyric acid, a tracer for PET studies on system A amino acid transport in vivo

International Nuclear Information System (INIS)

Sutinen, E.; Jyrkkioe, S.; Groenroos, T.; Haaparanta, M.; Lehikoinen, P.; Naagren, K.

2001-01-01

[N-methyl- 11 C]α-Methylaminoisobutyric acid ( 11 C-MeAIB) is a potentially useful tracer for positron emission tomography (PET) studies on hormonally regulated system A amino acid transport. 11 C-MeAIB is a metabolically stable amino acid analogue specific for system A amino acid transport. We evaluated the biodistribution of 11 C-MeAIB in rats and humans to estimate the usefulness of the tracer for in vivo human PET studies, for example, on regulation of system A amino acid transport and on tumour imaging. Healthy Sprague-Dawley rats (n=14) were killed 5, 20, 40 or 60 min after the injection of 11 C-MeAIB, and the tissue samples were weighed and counted for 11 C radioactivity. Ten lymphoma patients with relatively limited tumour burden underwent whole-body (WB) PET imaging with 11 C-MeAIB. In addition, three other patients had dynamic PET scanning of the head and neck area, and the tracer uptake was quantitated by calculating the kinetic influx constants (K i values) for the tracer. In animal studies, the highest activity was detected in the kidney, pancreas, adrenal gland and intestines. In humans, the highest activity was found in the salivary glands, and after that in the kidney and pancreas, similar to the results in animal studies. Rapid uptake was also detected in the skeletal muscle. In the graphical analysis, linear plots were obtained, and the mean fractional tracer uptake values (K i ) of the parotid glands (n=3) and cervical muscles (n=3) were 0.039±0.008 min -1 and 0.013±0.006 min -1 , respectively. The K i value of the tumour (n=1) was 0.064 min -1 . Higher uptake of 11 C-MeAIB into the tumour tissue was encountered. These results encourage further 11 C-MeAIB PET studies in humans on the physiology and pathology of system A amino acid transport and on tumour detection. (orig.)

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

Science.gov (United States)

Zimmermann, Karel; Gibrat, Jean-François

2010-01-04

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

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

Directory of Open Access Journals (Sweden)

Zimmermann Karel

2010-01-01

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

Synthesis and properties of radiation stabilized poly(α-amino acid)

International Nuclear Information System (INIS)

Nakagawa, T.; Shibata, T.

1981-01-01

In previous papers, one of the authors reported that modified poly(vinyl chloride) containing dithiocarbamate group has an excellent antiradiation property against γ-irradiation from the viewpoint of a negligibly small gaseous product, especially hydrogen chloride which was generated by radiolysis. Our studies of antiradiation polymers have now been extended to examine the stability of modified poly(α-amino acid) against γ-irradiation. Poly(α-amino acid) membranes have already been shown to be biologically compatible with blood and tissue. However, for practical uses of synthetic biomaterials, they would be required to be stable in the sterilization processing. The sterilization by γ-irradiation is more profitable for poly(α-amino acid) membranes which are less thermally stable. On the other hand, the transport of oxygen through poly(α-amino acid) membranes is of special interest because of the importance as a biomaterial for artificial lungs, skin and corneas. The purpose of the present study is to synthesize the antiradiation poly(α-amino acid) membranes by dithiocarbamate substitution, as well as to study the effect of dithiocarbamate substitution on the transport property of gases. (author)

Amino Acids and Chirality

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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.

Amino Acid Metabolism Disorders

Science.gov (United States)

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

Proteins and amino acids are fundamental to optimal nutrition support in critically ill patients

NARCIS (Netherlands)

Weijs, P.J.M.; Cynober, L.; DeLegge, M.; Kreymann, G.; Wernerman, J.; Wolfe, R.R.

2014-01-01

Proteins and amino acids are widely considered to be subcomponents in nutritional support. However, proteins and amino acids are fundamental to recovery and survival, not only for their ability to preserve active tissue (protein) mass but also for a variety of other functions. Understanding the

Uptake and conversion of D-amino acids in Arabidopsis thaliana.

Science.gov (United States)

Gördes, Dirk; Kolukisaoglu, Üner; Thurow, Kerstin

2011-02-01

The D-enantiomers of proteinogenic amino acids fulfill essential functions in bacteria, fungi and animals. Just in the plant kingdom, the metabolism and role of D-amino acids (D-AAs) still remains unclear, although plants have to cope with significant amounts of these compounds from microbial decay in the rhizosphere. To fill this gap of knowledge, we tested the inhibitory effects of D-AAs on plant growth and established a method to quantitate 16 out of 19 proteinogenic amino acids and their D-enantiomers in plant tissue extracts. Therefore, the amino acids in the extracts were derivatized with Marfey's reagent and separated by HPLC-MS. We used two ecotypes (Col-0 and C24) and a mutant (lht1) of the model plant Arabidopsis thaliana to determine the influence and fate of exogenously applied D-AAs. All of them were found in high concentrations in the plant extracts after application, even in lht1, which points to additional transporters facilitating the import of D-AAs. The addition of particular amino acids (D-Trp, D-Phe, D-Met and D-His) led to the accumulation of the corresponding L-amino acid. In almost all cases, the application of a D-AA resulted in the accumulation of D-Ala and D-Glu. The presented results indicate that soil borne D-AAs can actively be taken up and metabolized via central metabolic routes.

Branched-Chain Amino Acids

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Matteo Ghiringhelli

2015-07-01

Full Text Available Our study is focused on evaluation and use of the most effective and correct nutrients. In particular, our attention is directed to the role of certain amino acids in cachectic patients. During parenteral nutrition in humans, physician already associates in the PN-bags different formulations including amino acids, lipids and glucose solutions or essential amino acids solution alone or exclusively branched-chain amino acids (BCAA. Studies investigated the effects of dietary BCAA ingestion on different diseases and conditions such as obesity and metabolic disorders, liver disease, muscle atrophy, cancer, impaired immunity or injuries (surgery, trauma, burns, and sepsis. BCAAs have been shown to affect gene expression, protein metabolism, apoptosis and regeneration of hepatocytes, and insulin resistance. They have also been shown to inhibit the proliferation of liver cancer cells in vitro, and are essential for lymphocyte proliferation and dendritic cell maturation. Oral or parenteral administration of these three amino acids will allow us to evaluate the real efficacy of these compounds during a therapy to treat malnutrition in subjects unable to feed themselves.

Investigation on the pancreatic and stomach secretion in pigs by means of continuous infusion of /sup 14/C-amino acids

Energy Technology Data Exchange (ETDEWEB)

Simon, O; Bergner, H; Muenchmeyer, R [Humboldt-Universitaet, Berlin (German Democratic Republic). Sektion Tierproduktion und Veterinaermedizin; Zebrowska, T [Polska Akademia Nauk, Warsaw

1983-01-01

2 pigs received a barley-soya bean meal diet and another 2 a casein-wheat starch diet. The specific radioactivity (SR = dpm/..mu..mol) of leucine and phenylalanine in the TCA soluble fraction of plasma and in the TCA soluble and TCA precipitable fractions of pancreatic juice and of digesta leaving the stomach was determined during 6 hours of intravenous infusion of /sup 14/C-leucine and /sup 14/C-phenylalanine. At the end of the infusion the SR of both amino acids in both fractions of several tissues was measured and used for calculations of the rate of tissue protein synthesis. The results are that mainly amino acids derived from the extracellular space were used for synthesis that the process of synthesis, concentration and secretion of secretory proteins requires in pigs 120 to 180 minutes, and that TCA soluble amino acids in pancreatic juice are not free amino acids per se, but originate from processing of presecretory proteins. In the duodenal digesta labelled proteins appeared 3 to 4 hours after the beginning of the infusion. Both, secretion of proteins by the pancreas and by the stomach seemed to be more stimulated after feeding the barley-soya diet than the casein-starch diet. Of all tissues, the SR of amino acids in proteins was highest in the pancreas. However, proteins secreted by the pancreas were 3 to 4 times higher labelled than those retained in the tissue. The range of the fractional rate of protein synthesis was calculated for the sections of the gastrointestinal tract, the liver and skeletal muscles and discussed with other findings.

Carbobenzoxy amino acids: Structural requirements for cholecystokinin receptor antagonist activity

International Nuclear Information System (INIS)

Maton, P.N.; Sutliff, V.E.; Jensen, R.T.; Gardner, J.D.

1985-01-01

The authors used dispersed acini prepared from guinea pig pancreas to examine 28 carbobenzoxy (CBZ) amino acids for their abilities to function as cholecystokinin receptor antagonists. All amino acid derivatives tested, except for CBZ-alanine, CBZ-glycine, and N alpha-CBZ- lysine, were able to inhibit the stimulation of amylase secretion caused by the C-terminal octapeptide of cholecystokinin. In general, there was a good correlation between the ability of a carbobenzoxy amino acid to inhibit stimulated amylase secretion and the ability of the amino acid derivative to inhibit binding of 125 I-cholecystokinin. The inhibition of cholecystokinin-stimulated amylase secretion was competitive, fully reversible, and specific for those secretagogues that interact with the cholecystokinin receptor. The potencies with which the various carbobenzoxy amino acids inhibited the action of cholecystokinin varied 100-fold and CBZ-cystine was the most potent cholecystokinin receptor antagonist. This variation in potency was primarily but not exclusively a function of the hydrophobicity of the amino acid side chain

Amino acid sequence of bovine muzzle epithelial desmocollin derived from cloned cDNA: a novel subtype of desmosomal cadherins.

Science.gov (United States)

Koch, P J; Goldschmidt, M D; Walsh, M J; Zimbelmann, R; Schmelz, M; Franke, W W

1991-05-01

Desmosomes are cell-type-specific intercellular junctions found in epithelium, myocardium and certain other tissues. They consist of assemblies of molecules involved in the adhesion of specific cell types and in the anchorage of cell-type-specific cytoskeletal elements, the intermediate-size filaments, to the plasma membrane. To explore the individual desmosomal components and their functions we have isolated DNA clones encoding the desmosomal glycoprotein, desmocollin, using antibodies and a cDNA expression library from bovine muzzle epithelium. The cDNA-deduced amino-acid sequence of desmocollin (presently we cannot decide to which of the two desmocollins, DC I or DC II, this clone relates) defines a polypeptide with a calculated molecular weight of 85,000, with a single candidate sequence of 24 amino acids sufficiently long for a transmembrane arrangement, and an extracellular aminoterminal portion of 561 amino acid residues, compared to a cytoplasmic part of only 176 amino acids. Amino acid sequence comparisons have revealed that desmocollin is highly homologous to members of the cadherin family of cell adhesion molecules, including the previously sequenced desmoglein, another desmosome-specific cadherin. Using riboprobes derived from cDNAs for Northern-blot analyses, we have identified an mRNA of approximately 6 kb in stratified epithelia such as muzzle epithelium and tongue mucosa but not in two epithelial cell culture lines containing desmosomes and desmoplakins. The difference may indicate drastic differences in mRNA concentration or the existence of cell-type-specific desmocollin subforms. The molecular topology of desmocollin(s) is discussed in relation to possible functions of the individual molecular domains.

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

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

2011-01-01

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

Labeling of unnatural amino acids with sup(99m)Tc and tissue distribution of the labeled products in mice

International Nuclear Information System (INIS)

Tamemasa, Osamu; Goto, Rensuke; Takeda, Atsushi

1981-01-01

The selective affinity of amino acids for pancreas, due to its high rate of protein synthesis, has prompted us to synthesize new radio-labeled amino acids for pancreatic imaging. Labeling of 19 unnatural amino acids with sup(99m)Tc was tried in the usual way, and 10 labeled products were obtained with low yields. The highest distribution of radioactivity from all these labeled amino acids, which had been injected intravenously into mice, was found in the kidney, whereas little activity was found in the pancreas. Their low distributions in stomach suggest little dissociation of the labeled amino acids into sup(99m)TcO 4 - in mice. It is presumed that these labeled amino acids behave unlike their original amino acids in the body. (author)

Mapping the Hydropathy of Amino Acids Based on Their Local Solvation Structure

KAUST Repository

Bonella, S.

2014-06-19

In spite of its relevant biological role, no general consensus exists on the quantitative characterization of amino acid\\'s hydropathy. In particular, many hydrophobicity scales exist, often producing quite different rankings for the amino acids. To make progress toward a systematic classification, we analyze amino acids\\' hydropathy based on the orientation of water molecules at a given distance from them as computed from molecular dynamics simulations. In contrast with what is usually done, we argue that assigning a single number is not enough to characterize the properties of an amino acid, in particular when both hydrophobic and hydrophilic regions are present in a residue. Instead we show that appropriately defined conditional probability densities can be used to map the hydrophilic and hydrophobic groups on the amino acids with greater detail than possible with other available methods. Three indicators are then defined based on the features of these probabilities to quantify the specific hydrophobicity and hydrophilicity of each amino acid. The characterization that we propose can be used to understand some of the ambiguities in the ranking of amino acids in the current scales. The quantitative indicators can also be used in combination with standard bioinformatics tools to predict the location of transmembrane regions of proteins. The method is sensitive to the specific environment of the amino acids and can be applied to unnatural and modified amino acids, as well as to other small organic molecules. © 2014 American Chemical Society.

Branched-chain amino acid supplementation during bed rest: effect on recovery

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Stein, T. P.; Donaldson, M. R.; Leskiw, M. J.; Schluter, M. D.; Baggett, D. W.; Boden, G.

2003-01-01

Bed rest is associated with a loss of protein from the weight-bearing muscle. The objectives of this study are to determine whether increasing dietary branched-chain amino acids (BCAAs) during bed rest improves the anabolic response after bed rest. The study consisted of a 1-day ambulatory period, 14 days of bed rest, and a 4-day recovery period. During bed rest, dietary intake was supplemented with either 30 mmol/day each of glycine, serine, and alanine (group 1) or with 30 mmol/day each of the three BCAAs (group 2). Whole body protein synthesis was determined with U-(15)N-labeled amino acids, muscle, and selected plasma protein synthesis with l-[(2)H(5)]phenylalanine. Total glucose production and gluconeogenesis from alanine were determined with l-[U-(13)C(3)]alanine and [6,6-(2)H(2)]glucose. During bed rest, nitrogen (N) retention was greater with BCAA feeding (56 +/- 6 vs. 26 +/- 12 mg N. kg(-1). day(-1), P < 0.05). There was no effect of BCAA supplementation on either whole body, muscle, or plasma protein synthesis or the rate of 3-MeH excretion. Muscle tissue free amino acid concentrations were increased during bed rest with BCAA (0.214 +/- 0.066 vs. 0.088 +/- 0.12 nmol/mg protein, P < 0.05). Total glucose production and gluconeogenesis from alanine were unchanged with bed rest but were significantly reduced (P < 0.05) with the BCAA group in the recovery phase. In conclusion, the improved N retention during bed rest is due, at least in part, to accretion of amino acids in the tissue free amino acid pools. The amount accreted is not enough to impact protein kinetics in the recovery phase but does improve N retention by providing additional essential amino acids in the early recovery phase.

Amino acid racemisation dating

International Nuclear Information System (INIS)

Murray-Wallace, C.V.

1999-01-01

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

Studies on radiolysis of amino acids, 1

International Nuclear Information System (INIS)

Oku, Tadatake

1977-01-01

In order to elucidate the radiolysis of amino acid, peptide, protein and enzyme, the radiolytic mechanisms of neutral amino acids (glycine, L-alanine, L-valine, L-leucine, L-isoleucine, L-serine, and L-threonine) and acidic amino acids (L-aspartic acid, L-glutamic acid and DL-amino-n-adipic acid) were studied in the presence of air or in the atmosphere nitrogen. An aqueous solution of 1 mM. of each amino acid was sealed in a glass ampoule under air or nitrogen. Irradiation of amino acid solutions was carried out with γ-rays of 60 Co at doses of 4.4-2,640x10 3 rads. The amino acids and the radiolytic products formed were determined by ion-exchange chromatography. From the results of determining amino acids and the radiolytic products formed and their G-values, the radiolytic mechanisms of the amino acids were discussed. (auth.)

Assimilate unloading from maize (Zea mays L.) pedicel tissues. II. Effects of chemical agents on sugar, amino acid, and 14C-assimilate unloading

International Nuclear Information System (INIS)

Porter, G.A.; Knievel, D.P.; Shannon, J.C.

1987-01-01

Sugar, amino acid, and 14 C-assimilate release from attached maize (Zea mays L.) pedicels was studied following treatment with several chemical inhibitors. In the absence of these agents, sugar release was nearly linear over a 7-hour period. At least 13 amino acids were released with glutamine comprising over 30% of the total. Release was not affected by potassium concentration, 10-minute pretreatments with p-chloromercuribenzene sulfonic acid (PCMBS) or dithiothreitol, and low concentrations of CaCl 2 . Three hours or more exposure to PCMBS, dinitrophenol, N-ethylmaleimide, or 2,4,6-trinitrobenzene sulfonic acid strongly inhibited 14 C-assimilate, sugar, and amino acid release from the pedicel. These treatments also reduced 14 C-assimilate movement into the kernel bases. It is, therefore, likely that reduced unloading, caused by these relatively long-term exposures to chemical inhibitors, was related to reduced translocation of assimilates into treated kernels. Whether this effect is due to disruption of kernel metabolism and sieve element function or reduced assimilate unloading and subsequent accumulation of unlabeled assimilates within the pedicel tissues cannot be determined at this time

Evolutionary systems biology of amino acid biosynthetic cost in yeast.

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Michael D Barton

2010-08-01

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

Azetidinic amino acids

DEFF Research Database (Denmark)

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

2005-01-01

A set of ten azetidinic amino acids, that can be envisioned as C-4 alkyl substituted analogues of trans-2-carboxyazetidine-3-acetic acid (t-CAA) and/or conformationally constrained analogues of (R)- or (S)-glutamic acid (Glu) have been synthesized in a diastereo- and enantiomerically pure form from...... of two diastereoisomers that were easily separated and converted in two steps into azetidinic amino acids. Azetidines 35-44 were characterized in binding studies on native ionotropic Glu receptors and in functional assays at cloned metabotropic receptors mGluR1, 2 and 4, representing group I, II and III...... beta-amino alcohols through a straightforward five step sequence. The key step of this synthesis is an original anionic 4-exo-tet ring closure that forms the azetidine ring upon an intramolecular Michael addition. This reaction was proven to be reversible and to lead to a thermodynamic distribution...

Could Mineral Surfaces have Oriented Amino Acid Polymerization Towards Useful Products?

Science.gov (United States)

Lambert, J. F.; Sakhno, Y.; Battistella, A.; Ribetto, B.; Mezzetti, A.; Georgelin, T.; Jaber, M.; Michot, L.

2017-07-01

We investigated selective amino acid polymerization on the surface of silicic minerals. Specific amino acid couples were deposited on silica or clays, thermally activated, and the oligomers formed were analyzed. Very different behaviors were observed.

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

Science.gov (United States)

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

2015-11-01

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

Specific Labeling of Zinc Finger Proteins using Non-canonical Amino Acids and Copper-free Click Chemistry

Science.gov (United States)

Kim, Younghoon; Kim, Sung Hoon; Ferracane, Dean; Katzenellenbogen, John A.

2012-01-01

Zinc finger proteins (ZFPs) play a key role in transcriptional regulation and serve as invaluable tools for gene modification and genetic engineering. Development of efficient strategies for labeling metalloproteins such as ZFPs is essential for understanding and controlling biological processes. In this work, we engineered ZFPs containing cysteine-histidine (Cys2-His2) motifs by metabolic incorporation of the unnatural amino acid azidohomoalanine (AHA), followed by specific protein labeling via click chemistry. We show that cyclooctyne promoted [3 + 2] dipolar cycloaddition with azides, known as copper-free click chemistry, provides rapid and specific labeling of ZFPs at high yields as determined by mass spectrometry analysis. We observe that the DNA-binding activity of ZFPs labeled by conventional copper-mediated click chemistry was completely abolished, whereas ZFPs labeled by copper-free click chemistry retain their sequence-specific DNA-binding activity under native conditions, as determined by electrophoretic mobility shift assays, protein microarrays and kinetic binding assays based on Förster resonance energy transfer (FRET). Our work provides a general framework to label metalloproteins such as ZFPs by metabolic incorporation of unnatural amino acids followed by copper-free click chemistry. PMID:22871171

Impact of Branched-Chain Amino Acid Catabolism on Fatty Acid and Alkene Biosynthesis in Micrococcus luteus.

Science.gov (United States)

Surger, Maximilian J; Angelov, Angel; Stier, Philipp; Übelacker, Maria; Liebl, Wolfgang

2018-01-01

Micrococcus luteus naturally produces alkenes, unsaturated aliphatic hydrocarbons, and represents a promising host to produce hydrocarbons as constituents of biofuels and lubricants. In this work, we identify the genes for key enzymes of the branched-chain amino acid catabolism in M. luteus , whose first metabolic steps lead also to the formation of primer molecules for branched-chain fatty acid and olefin biosynthesis, and demonstrate how these genes can be used to manipulate the production of specific olefins in this organism. We constructed mutants of several gene candidates involved in the branched-chain amino acid metabolism or its regulation and investigated the resulting changes in the cellular fatty acid and olefin profiles by GC/MS. The gene cluster encoding the components of the branched-chain α-keto acid dehydrogenase (BCKD) complex was identified by deletion and promoter exchange mutagenesis. Overexpression of the BCKD gene cluster resulted in about threefold increased olefin production whereas deletion of the cluster led to a drastic reduction in branched-chain fatty acid content and a complete loss of olefin production. The specificities of the acyl-CoA dehydrogenases of the branched amino acid degradation pathways were deduced from the fatty acid and olefin profiles of the respective deletion mutant strains. In addition, growth experiments with branched amino acids as the only nitrogen source were carried out with the mutants in order to confirm our annotations. Both the deletion mutant of the BCKD complex, responsible for the further degradation of all three branched-chain amino acids, as well as the deletion mutant of the proposed isovaleryl-CoA dehydrogenase (specific for leucine degradation) were not able to grow on leucine in contrast to the parental strain. In conclusion, our experiments allow the unambigous assignment of specific functions to the genes for key enzymes of the branched-chain amino acid metabolism of M. luteus . We also show how

Compositional changes of proteins and amino acids in germinating coffee seeds

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Milton Massao Shimizu

2000-01-01

Full Text Available Endosperm is the main reserve tissue in coffee seeds. Coffee (Coffea arabica L. seeds were germinated for six weeks and qualitative and quantitative changes in amino acids and proteins were investigated. The total content of free amino acids were reduced during germination, however, protein content remained constant. SDS-PAGE profiles showed that legumin-like proteins became less stained in the last weeks. Asparagine, glutamic acid, aspartic acid, alanine and lysine were the major free amino acids, although serine and glutamine were also significant. Except for tyrosine, which increased with germination, all other amino acids were reduced. Analysis of the amino acid composition of the total soluble protein showed glutamic acid/glutamine and glycine as the main amino acids. However, other amino acids such as leucine, aspartic acid/asparagine, alanine, lysine, serine were also found in reasonable amounts.Endosperma é o principal tecido de reserva em sementes de café. Sementes de café (Coffea arabica L. foram germinadas por seis semanas e as alterações qualitativas e quantitativas de aminoácidos e proteínas foram investigadas. O conteúdo total de aminoácidos livres reduziu durante a germinação, no entanto, o conteúdo de proteínas permaneceu constante. Perfis eletroforéticos de proteínas em SDS-PAGE mostraram que proteínas do tipo legumina foram menos coradas nas últimas semanas. Asparagina, ácido glutâmico, ácido aspártico, alanina e lisina foram os principais aminoácidos, apesar de que serina e glutamina também estavam presentes em quantidades significativas. Exceto tirosina, a qual aumentou durante a germinação, todos os outros aminoácidos tiveram redução em sua concentração. A análise aminoacídica da fração de proteína solúvel total mostrou que ácido glutâmico/glutamina e glicina eram os principais aminoácidos presentes. No entanto, outros aminoácidos, tais como leucina, ácido asp

Biochemical studies on the effect of fluoride on higher plants. I. Metabolism of carbohydrates, organic acids and amino acids. [Glycine max var. Hawkeye

Energy Technology Data Exchange (ETDEWEB)

Yang, S F; Miller, G W

1963-01-01

Metabolic processes associated with free sugars, organic acids and amino acids in higher plants subjected to fluoride fumigation were studied quantitatively. Fluoride-fumigated leaves contained more reducing sugars and less sucrose than the normal leaves. This result suggested inhibition of sucrose synthesis by fluoride. Necrotic leaves contained increased total concentrations of organic acids, which were mostly attributable to malic acid, malonic acid and citric acid. The greater increase in malic acid relative to that of citric acid was the reverse of results observed in chlorotic tissue. Necrotic leaves contained enhanced amounts of free amino acids. The greatest increase occurred in the concentration of asparagine and might be related to the increased respiratory rate of necrotic leaves. Pipecolic acid accumulated in large quantities in nicrotic tissue and was not detected in normal leaves. The accumulation of organic acids and amino acids in leaves during fluoride fumigation was evidenced by a lowered respiratory quotient.

Biochemical and physiological bases for utilization of dietary amino acids by young Pigs.

Science.gov (United States)

Rezaei, Reza; Wang, Weiwei; Wu, Zhenlong; Dai, Zhaolai; Wang, Junjun; Wu, Guoyao

2013-02-27

Protein is quantitatively the most expensive nutrient in swine diets. Hence it is imperative to understand the physiological roles played by amino acids in growth, development, lactation, reproduction, and health of pigs to improve their protein nutrition and reduce the costs of pork production. Due to incomplete knowledge of amino acid biochemistry and nutrition, it was traditionally assumed that neonatal, post-weaning, growing-finishing, and gestating pigs could synthesize sufficient amounts of all "nutritionally nonessential amino acids" (NEAA) to support maximum production performance. Therefore, over the past 50 years, much emphasis has been placed on dietary requirements of nutritionally essential amino acids as building blocks for tissue proteins. However, a large body of literature shows that NEAA, particularly glutamine, glutamate, arginine and proline regulate physiological functions via cell signaling pathways, such as mammalian target of rapamycin, AMP-activated protein kinase, extracellular signal-related kinase, Jun kinase, mitogen-activated protein kinase, and NEAA-derived gaseous molecules (e.g., nitric oxide, carbon monoxide, and hydrogen sulfide). Available evidence shows that under current feeding programs, only 70% and 55% of dietary amino acids are deposited as tissue proteins in 14-day-old sow-reared piglets and in 30-day-old pigs weaned at 21 days of age, respectively. Therefore, there is an urgent need to understand the roles and dietary requirements of NEAA in swine nutrition. This review highlights the basic biochemistry and physiology of absorption and utilization of amino acids in young pigs to enhance the efficacy of utilization of dietary protein and to minimize excretion of nitrogenous wastes from the body.

Unnatural amino acids increase activity and specificity of synthetic substrates for human and malarial cathepsin C.

Science.gov (United States)

Poreba, Marcin; Mihelic, Marko; Krai, Priscilla; Rajkovic, Jelena; Krezel, Artur; Pawelczak, Malgorzata; Klemba, Michael; Turk, Dusan; Turk, Boris; Latajka, Rafal; Drag, Marcin

2014-04-01

Mammalian cathepsin C is primarily responsible for the removal of N-terminal dipeptides and activation of several serine proteases in inflammatory or immune cells, while its malarial parasite ortholog dipeptidyl aminopeptidase 1 plays a crucial role in catabolizing the hemoglobin of its host erythrocyte. In this report, we describe the systematic substrate specificity analysis of three cathepsin C orthologs from Homo sapiens (human), Bos taurus (bovine) and Plasmodium falciparum (malaria parasite). Here, we present a new approach with a tailored fluorogenic substrate library designed and synthesized to probe the S1 and S2 pocket preferences of these enzymes with both natural and a broad range of unnatural amino acids. Our approach identified very efficiently hydrolyzed substrates containing unnatural amino acids, which resulted in the design of significantly better substrates than those previously known. Additionally, in this study significant differences in terms of the structures of optimal substrates for human and malarial orthologs are important from the therapeutic point of view. These data can be also used for the design of specific inhibitors or activity-based probes.

Contributions of basic amino acids in the autolysis loop of factor XIa to serpin specificity.

Science.gov (United States)

Rezaie, Alireza R; Sun, Mao-fu; Gailani, David

2006-08-08

The autolysis loops (amino acids 143-154, chymotrypsinogen numbering) of plasma serine proteases play key roles in determining the specificity of protease inhibition by plasma serpins. We studied the importance of four basic residues (Arg-144, Lys-145, Arg-147, and Lys-149) in the autolysis loop of the coagulation protease factor XIa (fXIa) for inhibition by serpins. Recombinant fXIa mutants, in which these residues were replaced individually or in combination with alanine, were prepared. The proteases were compared to wild-type fXIa (fXIa-WT) with respect to their ability to activate factor IX in a plasma clotting assay, to hydrolyze the chromogenic substrate S2366, and to undergo inhibition by the C1-inhibitor (C1-INH), protein Z dependent protease inhibitor (ZPI), antithrombin (AT), and alpha(1)-protease inhibitor (alpha(1)-PI). All mutants exhibited normal activity in plasma and hydrolyzed S2366 with catalytic efficiencies similar to that of fXIa-WT. Inhibition of mutants by C1-INH was increased to varying degrees relative to that of fXIa-WT, with the mutant containing alanine replacements for all four basic residues (fXIa-144-149A) exhibiting an approximately 15-fold higher rate of inhibition. In contrast, the inhibition by ZPI was impaired 2-3-fold for single amino acid substitutions, and fXIa-144-149A was essentially resistant to inhibition by ZPI. Alanine substitution for Arg-147 impaired inhibition by AT approximately 7-fold; however, other substitutions did not affect it or slightly enhanced inhibition. Arg-147 was also required for inhibition by alpha(1)-PI. Cumulatively, the results demonstrate that basic amino acids in the autolysis loop of fXIa are important determinants of serpin specificity.

Amino acid diversity on the basis of cytochrome b gene in Kacang and Ettawa Grade goats

Directory of Open Access Journals (Sweden)

D. A. Lestari

2017-08-01

Full Text Available The objectives of study were to identify and assess the amino acid diversity of Cytochrome b (Cyt b gene, genetic marker and characteristic of specific amino acid in Kacang and Ettawa Grade goat. Nineteen heads of Kacang goat (KG and twelve heads of Ettawa Grade goat (EG were purposively sampled. The genomic DNA was isolated by Genomic DNA Mini Kit (Geneaid and amplified Cyt b using PCR method with CytbCapF and CytbCapR primers and was sequenced. The results showed that there were two specific amino acids that distinguish KG and EG goat with C. hircus and C. aegagrus and four specific amino acids that distinguish KG and EG goat with C. falconeri, but there were no specific amino acids can be used as a genetic marker to distinguish between Kacang and EG goat. In conclusion, specific amino acids in Cyt b gene can be used as a genetic marker among KG and EG goat with 3 goat others comparator.

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

Science.gov (United States)

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

2014-05-16

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

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

International Nuclear Information System (INIS)

Bridges, R.J.; Meister, A.

1985-01-01

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

Amino acids in the sedimentary humic and fulvic acids

Digital Repository Service at National Institute of Oceanography (India)

Sardessai, S.

acids in the coastal Arabian Sea sediments: whereas amino acids content of fulvic acids was lower than that of humic acids in the coastal sediments of Bay of Bengal. Slope sedimentary humic acids were relatively enriched in amino acids as compared...

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

Directory of Open Access Journals (Sweden)

Kyle J. Hackney

2014-07-01

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

Role of sialic acid in synaptosomal transport of amino acid transmitters

International Nuclear Information System (INIS)

Zaleska, M.M.; Erecinska, M.

1987-01-01

Active, high-affinity, sodium-dependent uptake of [ 14 C]-aminobutyric acid and of the acidic amino acid D-[ 3 H]-aspartate was inhibited by pretreatment of synaptosomes with neuraminidase from Vibrio cholerae. Inhibition was of a noncompetitive type and was related to the amount of sialic acid released. The maximum accumulation ratios of both amino acids (intracellular [amino acid]/extracellular [amino acid]) remained largely unaltered. Treatment with neuraminidase affected neither the synaptosomal energy levels nor the concentration of internal potassium. It is suggested that the γ-aminobutyric acid and acidic amino acid transporters are glycosylated and that sialic acid is involved in the operation of the carrier proteins directly and not through modification of driving forces responsible for amino acid uptake

SHORT COMMUNICATION DETERMINATION OF AMINO ACIDS ...

African Journals Online (AJOL)

B. S. Chandravanshi

The purpose of this study was to assess the levels of free and total amino acid ... Gas chromatographic method with flame ionization detector (GC-FID) was ... Total amino acid analysis was done on acid hydrolysates of RJ samples by the ion-exchange ... The data of amino acids and protein content for all analyzed fresh and.

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

Science.gov (United States)

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

2012-01-01

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

The gut microbiota modulates host amino acid and glutathione metabolism in mice

DEFF Research Database (Denmark)

Mardinoglu, Adil; Shoaie, Saeed; Bergentall, Mattias

2015-01-01

, liver, and adipose tissues. We used these functional models to determine the global metabolic differences between CONV-R and GF mice. Based on gene expression data, we found that the gut microbiota affects the host amino acid (AA) metabolism, which leads to modifications in glutathione metabolism...... conventionally raised (CONV-R) and germ-free (GF) mice using gene expression data and tissue-specific genome-scale metabolic models (GEMs). We created a generic mouse metabolic reaction (MMR) GEM, reconstructed 28 tissue-specific GEMs based on proteomics data, and manually curated GEMs for small intestine, colon....... To validate our predictions, we measured the level of AAs and N-acetylated AAs in the hepatic portal vein of CONV-R and GF mice. Finally, we simulated the metabolic differences between the small intestine of the CONV-R and GF mice accounting for the content of the diet and relative gene expression differences...

Cadmium toxicity induced contrasting patterns of concentrations of free sarcosine, specific amino acids and selected microelements in two Noccaea species.

Science.gov (United States)

Zemanová, Veronika; Pavlík, Milan; Pavlíková, Daniela

2017-01-01

Cadmium (Cd) toxicity affects numerous metabolic processes in plants. In the presence of Cd, plants accumulate specific amino acids which may be beneficial to developing Cd tolerance. Our study aimed to characterize the changes in the metabolism of selected free amino acids that are associated with Cd tolerance, and investigate the levels of selected microelements in order to relate these changes to the adaptation strategies of two metallophytes-Noccaea caerulescens (Redlschlag, Austria) and Noccaea praecox (Mežica, Slovenia). The plants were exposed to Cd contamination (90 mg Cd/kg soil) for 120 days in a pot experiment. Our results showed higher Cd accumulation in N. praecox compared to N. caerulescens. Cadmium contamination reduced the zinc and nickel levels in both species and a mixed effect was determined for copper and manganese content. Differences in free amino acid metabolism were observed between the two metallophytes growing under Cd-free and Cd-loaded conditions. Under Cd-free conditions, aromatic amino acids (phenylalanine, tryptophan and tyrosine) and branched-chain amino acids (leucine, isoleucine and valine) were accumulated more in the leaves of N. praecox than in N. caerulescens. Cd stress increased the content of these amino acids in both species but this increase was significant only in N. caerulescens leaves. Marked differences in the responses of the two species to Cd stress were shown for alanine, phenylalanine, threonine and sarcosine. Cadmium contamination also induced an increase of threonine as alanine and sarcosine decrease, which was larger in N. caerulescens than in N. praecox. All these factors contribute to the higher adaptation of N. praecox to Cd stress.

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

DEFF Research Database (Denmark)

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

1996-01-01

The homologous series of acidic amino acids, ranging from aspartic acid (1) to 2-aminosuberic acid (5), and the corresponding series of 3-isoxazolol bioisosteres of these amino acids, ranging from (RS)-2-amino-2-(3-hydroxy-5-methylisoxazol-4-yl)acetic acid (AMAA, 6) to (RS)-2-amino-6-(3-hydroxy-5......-methylisoxazol-4-yl)hexanoic acid (10), were tested as ligands for metabotropic excitatory amino acid receptors (mGlu1 alpha, mGlu2, mGlu4a, and mGlu6). Whereas AMAA (6) and (RS)-2-amino-3-(3-hydroxy-5-methylisoxazol-4-yl)propinoic acid (AMPA, 7) are potent and highly selective agonists at N......-methyl-D-aspartic acid (NMDA) and AMPA receptors, respectively, the higher homologue of AMPA (7), (RS)-2-amino-4-(3-hydroxy-5-methylisoxazol-4-yl)butyric acid (homo-AMPA, 8), is inactive at ionotropic excitatory amino acid receptors. Homo-AMPA (8), which is a 3-isoxazolol bioisostere of 2-aminoadipic acid (3), was...

Nucleic acid labeling with [3H]orotic acid and nucleotide profile in rats in protein deprivation, enteral and parenteral essential amino acid administration, and 5-fluorouracil treatment

International Nuclear Information System (INIS)

Jakobsson, B.; el Hag, I.A.; Andersson, M.; Christensson, P.I.; Stenram, U.

1990-01-01

Rats were fed a 0% casein diet for 1 week, with or without enteral or parenteral administration of essential amino acids, or a 25% casein diet, in one group supplemented with 5-fluorouracil treatment. Ninety minutes before sacrifice the rats were given a tracer of [3H]orotic acid. Incorporation into the acid soluble fraction, RNA, and DNA was determined in liver, small intestine, bone marrow, and kidney. Nucleotide profile was examined in liver and intestine. Protein deficiency caused inter alia a decrease in body weight; a decrease in RNA/DNA ratio and an increase in the specific RNA labeling in liver and kidney; an altered nucleotide profile in the liver; an increase in the nucleotide/DNA and RNA/DNA ratios and a decrease in the specific labeling of the acid soluble fraction, RNA, and DNA in the bone marrow. These changes were prevented to the same extent by giving essential amino acids, either orally or intravenously. The minor changes in intestinal nucleotide profile in protein deprivation were prevented to a slightly larger extent by amino acids orally than parenterally. 5-Fluorouracil treatment gave a decrease in the RNA/DNA ratio in the liver and kidney but an increase in the nucleotide/DNA and RNA/DNA ratios in the bone marrow. Nucleotide profiles were unaltered. The amount of DNA per gram of tissue decreased in bone marrow and increased in kidney. Parenteral administration per se resulted in almost no changes

The amino acid sequence of snapping turtle (Chelydra serpentina) ribonuclease

NARCIS (Netherlands)

Beintema, Jacob; Broos, Jaap; Meulenberg, Janneke; Schüller, Cornelis

1985-01-01

Snapping turtle (Chelydra serpentina) ribonuclease was isolated from pancreatic tissue. Turtle ribonuclease binds much more weakly to the affinity chromatography matrix used than mammalian ribonucleases. The amino acid sequence was determined from overlapping peptides obtained from three different

Free amino acids of leaves and berries of Cabernet Sauvignon grapevines

Directory of Open Access Journals (Sweden)

Alberto Miele

2000-03-01

Full Text Available The composition of free amino acids was studied from leaves, pericarps, skins, musts and seeds of Vitis vinifera L. cv. Cabernet Sauvignon. Vineyards were in the Bordeaux region and the grapevines were conducted in espalier and lyre systems. Grapes were collected at maturity and lyophilized after sampling. Extraction of free amino acids was done with a hydroalcoholic solution and their analysis was performed with an autoanalyzer. A standard of 34 amino acids was utilized for the qualitative analysis. The results showed that, for both espalier and lyre training systems, respectively, the free amino acids were predominant in the pericarps (12.85 and 11.21 mg/g dw - 16.88 and 15.12 mg/g dw in skins and 3.29 and 2.88 g/l in musts -, followed by the seeds (2.37 and 2.32 mg/g dw and leaves (1.87 and 1.98 mg/g dw. The most abundant free amino acids in leaves were glutamic acid (23.8 and 28.8 p. cent, aspartic acid (8.8 and 11.1 p. cent, and glutamine (10.1 and 9.4 p. cent. Proline (41.8 and 41.5 p. cent and arginine (22.8 and 22.4 p. cent predominated in the pericarps. In seeds, the main amino acids were proline (14.5 and 15.8 p. cent, arginine (11.0 and 11.8 p. cent, histidine (11.2 and 8.7 p. cent, and glutamic acid (11.3 and 8.2 p. cent. Grapevine training system showed some differences in the total amount and in the percentages of each free amino acid, but the pattern of these compounds for each tissue was similar for both training systems.

Optimization of short amino acid sequences classifier

Science.gov (United States)

Barcz, Aleksy; Szymański, Zbigniew

This article describes processing methods used for short amino acid sequences classification. The data processed are 9-symbols string representations of amino acid sequences, divided into 49 data sets - each one containing samples labeled as reacting or not with given enzyme. The goal of the classification is to determine for a single enzyme, whether an amino acid sequence would react with it or not. Each data set is processed separately. Feature selection is performed to reduce the number of dimensions for each data set. The method used for feature selection consists of two phases. During the first phase, significant positions are selected using Classification and Regression Trees. Afterwards, symbols appearing at the selected positions are substituted with numeric values of amino acid properties taken from the AAindex database. In the second phase the new set of features is reduced using a correlation-based ranking formula and Gram-Schmidt orthogonalization. Finally, the preprocessed data is used for training LS-SVM classifiers. SPDE, an evolutionary algorithm, is used to obtain optimal hyperparameters for the LS-SVM classifier, such as error penalty parameter C and kernel-specific hyperparameters. A simple score penalty is used to adapt the SPDE algorithm to the task of selecting classifiers with best performance measures values.

Nickel deficiency disrupts metabolism of ureides, amino acids, and organic acids of young pecan foliage.

Science.gov (United States)

Bai, Cheng; Reilly, Charles C; Wood, Bruce W

2006-02-01

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan.

Genetic variation in food choice behaviour of amino acid-deprived Drosophila.

Science.gov (United States)

Toshima, Naoko; Hara, Chieko; Scholz, Claus-Jürgen; Tanimura, Teiichi

2014-10-01

To understand homeostatic regulation in insects, we need to understand the mechanisms by which they respond to external stimuli to maintain the internal milieu. Our previous study showed that Drosophila melanogaster exhibit specific amino acid preferences. Here, we used the D.melanogaster Genetic Reference Panel (DGRP), which is comprised of multiple inbred lines derived from a natural population, to examine how amino acid preference changes depending on the internal nutritional state in different lines. We performed a two-choice preference test and observed genetic variations in the response to amino acid deprivation. For example, a high-responding line showed an enhanced preference for amino acids even after only 1day of deprivation and responded to a fairly low concentration of amino acids. Conversely, a low-responding line showed no increased preference for amino acids after deprivation. We compared the gene expression profiles between selected high- and the low-responding lines and performed SNP analyses. We found several groups of genes putatively involved in altering amino acid preference. These results will contribute to future studies designed to explore how the genetic architecture of an organism evolves to adapt to different nutritional environments. Copyright © 2014 Elsevier Ltd. All rights reserved.

Impact of Sampling and Cellular Separation on Amino Acid Determinations in Drosophila Hemolymph.

Science.gov (United States)

Cabay, Marissa R; Harris, Jasmine C; Shippy, Scott A

2018-04-03

The fruit fly is a frequently used model system with a high degree of human disease-related genetic homology. The quantitative chemical analysis of fruit fly tissues and hemolymph uniquely brings chemical signaling and compositional information to fly experimentation. The work here explores the impact of measured chemical content of hemolymph with three aspects of sample collection and preparation. Cellular content of hemolymph was quantitated and removed to determine hemolymph composition changes for seven primary amine analytes. Hemolymph sampling methods were adapted to determine differences in primary amine composition of hemolymph collected from the head, antenna, and abdomen. Also, three types of anesthesia were employed with hemolymph collection to quantitate effects on measured amino acid content. Cell content was found to be 45.4 ± 22.1 cells/nL of hemolymph collected from both adult and larvae flies. Cell-concentrated fractions of adult, but not larvae, hemolymph were found to have higher and more variable amine content. There were amino acid content differences found between all three areas indicating a robust method to characterize chemical markers from specific regions of a fly, and these appear related to physiological activity. Methods of anesthesia have an impact on hemolymph amino acid composition related to overall physiological impact to fly including higher amino acid content variability and oxygen deprivation effects. Together, these analyses identify potential complications with Drosophila hemolymph analysis and opportunities for future studies to relate hemolymph content with model physiological activity.

Nutritional and medicinal aspects of D-amino acids.

Science.gov (United States)

Friedman, Mendel; Levin, Carol E

2012-05-01

This paper reviews and interprets a method for determining the nutritional value of D-amino acids, D-peptides, and amino acid derivatives using a growth assay in mice fed a synthetic all-amino acid diet. A large number of experiments were carried out in which a molar equivalent of the test compound replaced a nutritionally essential amino acid such as L-lysine (L-Lys), L-methionine (L-Met), L-phenylalanine (L-Phe), and L-tryptophan (L-Trp) as well as the semi-essential amino acids L-cysteine (L-Cys) and L-tyrosine (L-Tyr). The results show wide-ranging variations in the biological utilization of test substances. The method is generally applicable to the determination of the biological utilization and safety of any amino acid derivative as a potential nutritional source of the corresponding L-amino acid. Because the organism is forced to use the D-amino acid or amino acid derivative as the sole source of the essential or semi-essential amino acid being replaced, and because a free amino acid diet allows better control of composition, the use of all-amino-acid diets for such determinations may be preferable to protein-based diets. Also covered are brief summaries of the widely scattered literature on dietary and pharmacological aspects of 27 individual D-amino acids, D-peptides, and isomeric amino acid derivatives and suggested research needs in each of these areas. The described results provide a valuable record and resource for further progress on the multifaceted aspects of D-amino acids in food and biological samples.

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

DEFF Research Database (Denmark)

Madsen, U; Sløk, F A; Stensbøl, T B

2000-01-01

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

A putative role for amino acid permeases in sink-source communication of barley tissues uncovered by RNA-seq

Directory of Open Access Journals (Sweden)

Kohl Stefan

2012-08-01

Full Text Available Abstract Background The majority of nitrogen accumulating in cereal grains originates from proteins remobilised from vegetative organs. However, interactions between grain filling and remobilisation are poorly understood. We used transcriptome large-scale pyrosequencing of flag leaves, glumes and developing grains to identify cysteine peptidase and N transporter genes playing a role in remobilisation and accumulation of nitrogen in barley. Results Combination of already known and newly derived sequence information reduced redundancy, increased contig length and identified new members of cysteine peptidase and N transporter gene families. The dataset for N transporter genes was aligned with N transporter amino acid sequences of rice and Arabidopsis derived from Aramemnon database. 57 AAT, 45 NRT1/PTR and 22 OPT unigenes identified by this approach cluster to defined subgroups in the respective phylogenetic trees, among them 25 AAT, 8 NRT1/PTR and 5 OPT full-length sequences. Besides, 59 unigenes encoding cysteine peptidases were identified and subdivided into different families of the papain cysteine peptidase clade. Expression profiling of full-length AAT genes highlighted amino acid permeases as the group showing highest transcriptional activity. HvAAP2 and HvAAP6 are highly expressed in vegetative organs whereas HvAAP3 is grain-specific. Sequence similarities cluster HvAAP2 and the putative transporter HvAAP6 together with Arabidopsis transporters, which are involved in long-distance transfer of amino acids. HvAAP3 is closely related to AtAAP1 and AtAAP8 playing a role in supplying N to developing seeds. An important role in amino acid re-translocation can be considered for HvLHT1 and HvLHT2 which are specifically expressed in glumes and flag leaves, respectively. PCA and K-means clustering of AAT transcript data revealed coordinate developmental stages in flag leaves, glumes and grains. Phloem-specific metabolic compounds are proposed that

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

Energy Technology Data Exchange (ETDEWEB)

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

2014-12-15

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

Amino Acid Isotope Incorporation and Enrichment Factors in Pacific Bluefin Tuna, Thunnus orientalis

Science.gov (United States)

Bradley, Christina J.; Madigan, Daniel J.; Block, Barbara A.; Popp, Brian N.

2014-01-01

Compound specific isotopic analysis (CSIA) of amino acids has received increasing attention in ecological studies in recent years due to its ability to evaluate trophic positions and elucidate baseline nutrient sources. However, the incorporation rates of individual amino acids into protein and specific trophic discrimination factors (TDFs) are largely unknown, limiting the application of CSIA to trophic studies. We determined nitrogen turnover rates of individual amino acids from a long-term (up to 1054 days) laboratory experiment using captive Pacific bluefin tuna, Thunnus orientalis (PBFT), a large endothermic pelagic fish fed a controlled diet. Small PBFT (white muscle δ15N∼11.5‰) were collected in San Diego, CA and transported to the Tuna Research and Conservation Center (TRCC) where they were fed a controlled diet with high δ15N values relative to PBFT white muscle (diet δ15N∼13.9‰). Half-lives of trophic and source amino acids ranged from 28.6 to 305.4 days and 67.5 to 136.2 days, respectively. The TDF for the weighted mean values of amino acids was 3.0 ‰, ranging from 2.2 to 15.8 ‰ for individual combinations of 6 trophic and 5 source amino acids. Changes in the δ15N values of amino acids across trophic levels are the underlying drivers of the trophic 15N enrichment. Nearly all amino acid δ15N values in this experiment changed exponentially and could be described by a single compartment model. Significant differences in the rate of 15N incorporation were found for source and trophic amino acids both within and between these groups. Varying half-lives of individual amino acids can be applied to migratory organisms as isotopic clocks, determining the length of time an individual has spent in a new environment. These results greatly enhance the ability to interpret compound specific isotope analyses in trophic studies. PMID:24465724

Effect of nerve growth factor on the synthesis of amino acids in PC12 cells

International Nuclear Information System (INIS)

Zielke, H.R.; Tildon, J.T.; Kauffman, F.C.; Baab, P.J.

1989-01-01

Radioactive short-chain fatty acids preferentially label glutamine relative to glutamate in brain due to compartmentation of glutamine and glutamate. To determine whether this phenomenon occurs in a single cell culture model, we examined the effect of fatty acid chain length on the synthesis as well as pool size of selected amino acids in rat pheochromocytoma PC12 cells, a cell culture model of the large glutamate compartment in neurons. Intracellular 14C-amino acids were quantitated by HPLC, and the incorporation of [U-14C]-glucose, [1-14C]-butyrate, [1-14C]-octanoate, and [1-14C]-palmitate into five amino acids was measured in native and NGF-treated PC12 cells. NGF pretreatment decreased the intracellular concentration of amino acids as did addition of fatty acids but these effects were not additive. Specific activities of amino acids in native cells labelled by 14C-octanoate were 1,300 DPM/nmol, 490 DPM/nmol, 200 DPM/nmol, and 110 DPM/nmol for glutamate, aspartate, glutamine, and serine, respectively. No radioactivity was detected in alanine. Similar specific activities were noted when 14C-butyrate was the precursor; however, there was at least 5-fold less if 14C-palmitate was the precursor. Pretreatment of cells with NGF decreased the specific activity of amino acids by 25-65%. Specific activities of amino acids synthesized from 14C-glucose decreased in the following order: glutamate, 1,640 DPM/nmol; aspartate, 1,210 DPM/nmol; alanine, 580 DPM/nmol; glutamine, 275 DPM/nmol; and serine, 80 DPM/nmol for native cells. NGF pretreatment decreased the specific activities of glutamate and glutamine, but not of the other 3 amino acids. The preferred precursor for glutamate synthesis in native PC12 cells was glucose followed by octanoate, butyrate and palmitate (16:6:3:1)

Deuterium oxide as a tool for the study of amino acid metabolism

International Nuclear Information System (INIS)

Mitra, R.; Burton, J.; Varner, J.E.

1976-01-01

We have used deuterium oxide in nontoxic concentrations to study, in intact seedlings, the biosynthesis of amino acids. The extent and pattern of deuteration, as determined by a gas--liquid chromatograph--mass spectrometer system, permits conclusions about the biosynthesis of individual amino acids and also about their exposure to transaminases and other enzymes that might introduce deuterium into specific positions of the amino acid by exchange. This method could be used to study amino acid biogenesis in any organism that can tolerate 20 to 40 percent deuterium oxide for a period of a few hours to a few days

Synthesis of some labelled non-proteinogenic amino acids

International Nuclear Information System (INIS)

Adrianens, P.; Vanderhaeghe, H.

1987-01-01

The literature on the synthesis of labeled non-proteinogenic amino acids contains approximately 300 papers, whereas syntheses of labeled proteinogenic amino acids are dealt with in some 800-1000 publications. However, most of the methods described in this paper for the synthesis of non-proteinogenic amino acids are also used for the preparation of the essential amino acids addition, the first category also contains β, γ...amino acids, seleno amino acids, N-methyl and α-methyl amino acids and sometimes have atoms or groups which are not present in the protein building blocks. Furthermore the latter group is more easily available so that methods for synthesis of non-proteinogenic amino acids are more needed

Amino Acid Crossword Puzzle

Science.gov (United States)

Sims, Paul A.

2011-01-01

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

Amino acid composition of some Mexican foods.

Science.gov (United States)

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

2005-06-01

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

Present Global Situation of Amino Acids in Industry.

Science.gov (United States)

Tonouchi, Naoto; Ito, Hisao

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

"Facilitated" amino acid transport is upregulated in brain tumors.

Science.gov (United States)

Miyagawa, T; Oku, T; Uehara, H; Desai, R; Beattie, B; Tjuvajev, J; Blasberg, R

1998-05-01

The goal of this study was to determine the magnitude of "facilitated" amino acid transport across tumor and brain capillaries and to evaluate whether amino acid transporter expression is "upregulated" in tumor vessels compared to capillaries in contralateral brain tissue. Aminocyclopentane carboxylic acid (ACPC), a non-metabolized [14C]-labeled amino acid, and a reference molecule for passive vascular permeability, [67Ga]-gallium-diethylenetriaminepentaacetic acid (Ga-DTPA), were used in these studies. Two experimental rat gliomas were studied (C6 and RG2). Brain tissue was rapidly processed for double label quantitative autoradiography 10 minutes after intravenous injection of ACPC and Ga-DTPA. Parametric images of blood-to-brain transport (K1ACPC and K1Ga-DTPA, microL/min/g) produced from the autoradiograms and the histology were obtained from the same tissue section. These three images were registered in an image array processor; regions of interest in tumor and contralateral brain were defined on morphologic criteria (histology) and were transferred to the autoradiographic images to obtain mean values. The facilitated component of ACPC transport (deltaK1ACPC) was calculated from the K1ACPC and K1Ga-DTPA data, and paired comparisons between tumor and contralateral brain were performed. ACPC flux, K1ACPC, across normal brain capillaries (22.6 +/- 8.1 microL/g/min) was >200-fold greater than that of Ga-DTPA (0.09 +/- 0.04 microL/g/min), and this difference was largely (approximately 90%) due to facilitated ACPC transport. Substantially higher K1ACPC values compared to corresponding K1DTPA values were also measured in C6 and RG2 gliomas. The deltaK1ACPC values for C6 glioma were more than twice that of contralateral brain cortex. K1ACPC and deltaK1ACPC values for RG2 gliomas was not significantly higher than that of contralateral cortex, although a approximately 2-fold difference in facilitated transport is obtained after normalization for differences in capillary

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

OpenAIRE

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

2001-01-01

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

Synthesis and structure-activity studies on acidic amino acids and related diacids as NMDA receptor ligands

DEFF Research Database (Denmark)

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

1994-01-01

The 3-isoxazolol amino acids (S)-2-amino-3-(3-hydroxy-5-methyl-4- isoxazolyl)propionic acid [(S)-AMPA, 2] and (R,S)-2-amino-2-(3-hydroxy-5-methyl-4-isoxazolyl)acetic acid (AMAA, 5a) (Figure 1) are potent and specific agonists at the AMPA and N-methyl-D-aspartic acid (NMDA) subtypes, respectively......, of (S)-glutamic acid (1) receptors. A number of amino acids and diacids structurally related to AMAA were synthesized and tested electrophysiologically and in receptor-binding assays. The hydroxymethyl analogue 7c of AMAA was an NMDA agonist approximately equipotent with AMAA in the [3H...... by molecular mechanics calculations. Compound 7a possesses extra steric bulk and shows significant restriction of conformational flexibility compared to AMAA and 7c, which may be determining factors for the observed differences in biological activity. Although the nitrogen atom of quinolinic acid (6) has very...

carcass amino acid composition and utilization of dietary amino

African Journals Online (AJOL)

Maynard (1954), Fisher & Scott (1954), Forbes &. Rao (1959), Hartsook & Mitchell (1956). King (1963) showed that individual amino acids in the carcass could differ widely from the requirement by the anirnal for those particular amino acids used for purposes other than protein synthesis and subsequent retention. How-.

Serum neuron-specific enolase, biogenic amino-acids and neurobehavioral function in lead-exposed workers from lead-acid battery manufacturing process.

Science.gov (United States)

Ravibabu, K; Barman, T; Rajmohan, H R

2015-01-01

The interaction between serum neuron-specific enolase (NSE), biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin) levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs). In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests---simple reaction time (SRT), symbol digit substitution test (SDST), and serial digit learning test (SDLT). There was a significant correlation (r 0.199, pSDLT and SRT had also a significant positive correlation (r 0.238, p<0.01). NSE had a negative correlation (r -0.194, p<0.05) with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the "attention and perception" (SDST).

Post hoc analysis of plasma amino acid profiles: towards a specific pattern in autism spectrum disorder and intellectual disability.

Science.gov (United States)

Delaye, Jean-Baptiste; Patin, Franck; Lagrue, Emmanuelle; Le Tilly, Olivier; Bruno, Clement; Vuillaume, Marie-Laure; Raynaud, Martine; Benz-De Bretagne, Isabelle; Laumonnier, Frederic; Vourc'h, Patrick; Andres, Christian; Blasco, Helene

2018-01-01

Objectives Autism spectrum disorders and intellectual disability present a challenge for therapeutic and dietary management. We performed a re-analysis of plasma amino acid chromatography of children with autism spectrum disorders ( n = 22) or intellectual disability ( n = 29) to search for a metabolic signature that can distinguish individuals with these disorders from controls ( n = 30). Methods We performed univariate and multivariate analyses using different machine learning strategies, from the raw data of the amino acid chromatography. Finally, we analysed the metabolic pathways associated with discriminant biomarkers. Results Multivariate analysis revealed models to discriminate patients with autism spectrum disorders or intellectual disability and controls from plasma amino acid profiles ( P intellectual disability patients shared similar differences relative to controls, including lower glutamate ( P intellectual disability revealed the involvement of urea, 3-methyl-histidine and histidine metabolism. Biosigner analysis and univariate analysis confirmed the role of 3-methylhistidine ( P = 0.004), histidine ( P = 0.003), urea ( P = 0.0006) and lysine ( P = 0.002). Conclusions We revealed discriminant metabolic patterns between autism spectrum disorders, intellectual disability and controls. Amino acids known to play a role in neurotransmission were discriminant in the models comparing autism spectrum disorders or intellectual disability to controls, and histidine and b-alanine metabolism was specifically highlighted in the model.

Extraterrestrial Amino Acids in the Almahata Sitta Meteorite

Science.gov (United States)

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

2010-01-01

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

Amino Acid Stability in the Early Oceans

Science.gov (United States)

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

2015-01-01

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

Ultrasound-assisted extraction of amino acids from grapes.

Science.gov (United States)

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

2015-01-01

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

Optical Sensors for Detection of Amino Acids.

Science.gov (United States)

Pettiwala, Aafrin M; Singh, Prabhat K

2017-11-06

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

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

Science.gov (United States)

Mouw, M; Pintel, D J

1998-11-10

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

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

Science.gov (United States)

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

2015-10-01

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

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

Directory of Open Access Journals (Sweden)

Jumpei Sasabe

2018-05-01

Full Text Available Mammalian innate and adaptive immune systems use the pattern recognition receptors, such as toll-like receptors, to detect conserved bacterial and viral components. Bacteria synthesize diverse D-amino acids while eukaryotes and archaea generally produce two D-amino acids, raising the possibility that many of bacterial D-amino acids are bacteria-specific metabolites. Although D-amino acids have not been identified to bind to any known pattern recognition receptors, D-amino acids are enantioselectively recognized by some other receptors and enzymes including a flavoenzyme D-amino acid oxidase (DAO in mammals. At host–microbe interfaces in the neutrophils and intestinal mucosa, DAO catalyzes oxidation of bacterial D-amino acids, such as D-alanine, and generates H2O2, which is linked to antimicrobial activity. Intestinal DAO also modifies the composition of microbiota through modulation of growth for some bacteria that are dependent on host nutrition. Furthermore, regulation and recognition of D-amino acids in mammals have additional meanings at various host–microbe interfaces; D-phenylalanine and D-tryptophan regulate chemotaxis of neutrophils through a G-coupled protein receptor, D-serine has a bacteriostatic role in the urinary tract, D-phenylalanine and D-leucine inhibit innate immunity through the sweet taste receptor in the upper airway, and D-tryptophan modulates immune tolerance in the lower airway. This mini-review highlights recent evidence supporting the hypothesis that D-amino acids are utilized as inter-kingdom communication at host–microbe interface to modulate bacterial colonization and host defense.

[Effect of glucocorticoides on the release of amino acids in the perfused rat hindquarter (author's transl)].

Science.gov (United States)

Thienhaus, R; Tharandt, L; Zais, U; Staib, W

1975-06-01

The release of amino acids by skeletal muscle was studied in the isolated perfused rat hindquarter. Adrenalectomy depressed the formation of glutamine and alanine as well as the efflux of all other amino acids measured. Betamethasone--a synthetic glucocorticoid--caused a significant increase in the efflux of nearly all amino acids up to the level of normal controls. The release of amino acids was also increased in perfused hindquarters of diabetic rats. On the other hand, insulin exhibited a depressing effect on the release of amino acids by hindquarters of normal rats. The metabolic integrity of the muscle tissue was proved by measuring creatine phosphate, ATP, ADP and water content as well as by the significant insulin effect on glucose uptake and on [14C]leucine incorporation into muscle proteins.

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

Science.gov (United States)

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

2016-01-01

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

Specificity of the amino acid content of endogenous regulatory oligopeptides.

Science.gov (United States)

Zamyatnin, A A

1991-07-01

The amino acid residue content of endogenous regulatory oligopeptides possessing a certain spectrum of functional activity has been analyzed. It has been shown that compared to proteins, the oligopeptides contain a greater number of positively charged and cyclic radicals. All 579 oligopeptides contained in the EROP-Moscow data bank with the given spectrum of functional activity have been found to have common physicochemical characteristics.

Branched-chain amino acids for hepatic encephalopathy

DEFF Research Database (Denmark)

Als-Nielsen, B; Koretz, R L; Kjaergard, L L

2003-01-01

Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy.......Hepatic encephalopathy may be caused by a decreased plasma ratio of branched-chain amino acids (BCAA) to aromatic amino acids. Treatment with BCAA may therefore have a beneficial effect on patients with hepatic encephalopathy....

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

Science.gov (United States)

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

2018-03-01

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

Free amino acids in synaptic vesicles isolated from the cerebellum and cerebral hemispheres of control and neonatally X-irradiated rats

International Nuclear Information System (INIS)

Valcana, T.; Hudson, D.B.; Timiras, P.S.

1984-01-01

X-irradiation of the rat brain (1000R, at two days of age), suppresses the normal age-related increase in the weight of the cerebellum and cerebral hemispheres and influences amino acid levels. The decrease in glutamic acid concentration, particularly in the cerebellum, supports the previously advanced proposition that this amino acid may be associated with or may be the transmitter of, the rat cerebellar granule cells. Subfractionation of the cerebellar tissue reveals that the decrease in the glutamic acid level consequent to the loss of granule cells, is reflected in the cytoplasmic fraction but not in the synaptic vesicle subfraction, where glutamic acid was increased. The reduced weight gain in the cerebral hemispheres after irradiation, is accompanied by a significant decrease of aspartate in the cytoplasmic fraction, changes which suggest that a specific cell type, with aspartic acid as its neurotransmitter (possibly in the hippocampus), may also be radiosensitive in the early postnatal period. In contrast, in the synaptic vesicle fraction from cerebral hemispheres, all free amino acids, with the exception of glutamine, increased significantly. Overall, the changes in free amino acid concentration induced by X-irradiation in the cytoplasmic fraction in both brain regions studied are opposite to those found in the synaptic vesicle fraction and although they may indicate changes in specific cell populations, as proposed above, they could also reflect changes in cellular compartmentalization and metabolism or changes in the relative axonal arborization of the affected regions

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

Science.gov (United States)

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

2011-03-01

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

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

Directory of Open Access Journals (Sweden)

Sherine N. Khattab

2005-09-01

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

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

Science.gov (United States)

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

2017-12-01

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

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

Directory of Open Access Journals (Sweden)

Álvaro José de Almeida Bicudo

2014-03-01

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

Potential Biomarker of L type Amino Acid Transporter 1 in Breast Cancer Progression

International Nuclear Information System (INIS)

Liang, Zhongxing; Cho, Heidi T.; Williams, Larry; Zhu, Aizhi; Liang, Ke; Huang, Ke; Wu, Hui; Jiang, Chunsu; Hong, Samuel; Crowe, Ronald; Goodman, Mark M.; Shim, Hyunsuk

2011-01-01

L type amino acid transporter 1 (LAT1) is essential for the transport of large neutral amino acids. However, its role in breast cancer growth remains largely unknown. The purpose of the study is to investigate whether LAT1 is a potential biomarker for the diagnosis and treatment of breast cancer. LAT1 mRNA and protein levels in breast cancer cell lines and tissues were analyzed. In addition, the effects of targeting LAT1 for the inhibition of breast cancer cell tumorigenesis were assessed with soft agar assay. The imaging of xenograft with 1 amino 3 [ 18F ]fluorocyclo butane 1 carboxylic acid ([ 18F ]FACBC) PET was assessed for its diagnostic biomarker potential. Normal breast tissue or low malignant cell lines expressed low levels of LAT1 mRNA and protein, while highly malignant cancer cell lines and high grade breast cancer tissue expressed high levels of LAT1. In addition, higher expression levels of LAT1 in breast cancer tissues were consistent with advanced stage breast cancer. Furtermore, the blockade of LAT1 with its inhibitor, 2 amino bicyclo[2.2.1]heptane 2 carboxylic acid (BCH), or the knockdown of LAT1 with siRNA, inhibited proliferation and tumorigenesis of breast cancer cells. A leucine analog, [ 18F ]FACBC, has been demonstrated to be an excellent PET tracer for the non invasive imaging og malignant breast cancer using an orthotopic animal model. The overexpression of LAT1 is required for the progression of breast cancer. LAT1 represents a potential biomarker for therapy and diagnosis of breast cancer. [ 18F ]FACBC that correlates with LAT1 function is a potential PET tracer for malignant breast tumor imaging

Production of α-keto acids Part I. Immobilized cells ofTrigonopsis variabilis containing D-amino acid oxidase.

Science.gov (United States)

Brodelius, P; Nilsson, K; Mosbach, K

1981-12-01

Whole cells ofTrigonopsis variabilis were immobilized by entrapment in Ca(2+)-alginate and used for the production of α-keto acids from the corresponding D-amino acids. The D-amino acid oxidase within the immobilized cells has a broad substrate specificity. Hydrogen peroxide formed in the enzymatic reaction was efficiently hydrolyzed by manganese oxide co-immobilized with the cells. The amino acid oxidase activity was assayed with a new method based on reversed-phase HPLC. Oxygen requirements, bead size, concentration of cells in the beads, flow rate, and other factors were investigated in a " trickle-bed " reactor.

Discovery and History of Amino Acid Fermentation.

Science.gov (United States)

Hashimoto, Shin-Ichi

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

Serum Neuron-Specific Enolase, Biogenic Amino-Acids and Neurobehavioral Function in Lead-Exposed Workers from Lead-Acid Battery Manufacturing Process

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K Ravibabu

2015-01-01

Full Text Available Background: The interaction between serum neuron-specific enolase (NSE, biogenic amino-acids and neurobehavioral function with blood lead levels in workers exposed to lead form lead-acid battery manufacturing process was not studied. Objective: To evaluate serum NSE and biogenic amino-acids (dopamine and serotonin levels, and neurobehavioral performance among workers exposed to lead from lead-acid storage battery plant, and its relation with blood lead levels (BLLs. Methods: In a cross-sectional study, we performed biochemical and neurobehavioral function tests on 146 workers exposed to lead from lead-acid battery manufacturing process. BLLs were assessed by an atomic absorption spectrophotometer. Serum NSE, dopamine and serotonin were measured by ELISA. Neurobehavioral functions were assessed by CDC-recommended tests—simple reaction time (SRT, symbol digit substitution test (SDST, and serial digit learning test (SDLT. Results: There was a significant correlation (r 0.199, p<0.05 between SDST and BLL. SDLT and SRT had also a significant positive correlation (r 0.238, p<0.01. NSE had a negative correlation (r –0.194, p<0.05 with serotonin level. Multiple linear regression analysis revealed that both SRT and SDST had positive significant associations with BLL. SRT also had a positive significant association with age. Conclusion: Serum NSE cannot be used as a marker for BLL. The only domain of neurobehavioral function tests that is affected by increased BLL in workers of lead-acid battery manufacturing process is that of the “attention and perception” (SDST.

Amino acid metabolism conflicts with protein diversity

OpenAIRE

Krick, Teresa; Shub, David A.; Verstraete, Nina; Ferreiro, Diego U.; Alonso, Leonardo G.; Shub, Michael; Sanchez, Ignacio E.

2014-01-01

The 20 protein-coding amino acids are found in proteomes with different relative abundances. The most abundant amino acid, leucine, is nearly an order of magnitude more prevalent than the least abundant amino acid, cysteine. Amino acid metabolic costs differ similarly, constraining their incorporation into proteins. On the other hand, a diverse set of protein sequences is necessary to build functional proteomes. Here, we present a simple model for a cost-diversity trade-off postulating that n...

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

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

2015-04-01

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

Sugar amino acids and related molecules

Indian Academy of Sciences (India)

Sugar amino acids constitute an important class of such polyfunctional scaffolds where the carboxyl, amino and hydroxyl termini provide an excellent opportunity to organic chemists to create structural diversities akin to Nature's molecular arsenal. In recent years, sugar amino acids have been used extensively in the area of ...

Sensitive and specific detection of the non-human sialic Acid N-glycolylneuraminic acid in human tissues and biotherapeutic products.

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Sandra L Diaz

Full Text Available Humans are genetically defective in synthesizing the common mammalian sialic acid N-glycolylneuraminic acid (Neu5Gc, but can metabolically incorporate it from dietary sources (particularly red meat and milk into glycoproteins and glycolipids of human tumors, fetuses and some normal tissues. Metabolic incorporation of Neu5Gc from animal-derived cells and medium components also results in variable contamination of molecules and cells intended for human therapies. These Neu5Gc-incorporation phenomena are practically significant, because normal humans can have high levels of circulating anti-Neu5Gc antibodies. Thus, there is need for the sensitive and specific detection of Neu5Gc in human tissues and biotherapeutic products. Unlike monoclonal antibodies that recognize Neu5Gc only in the context of underlying structures, chicken immunoglobulin Y (IgY polyclonal antibodies can recognize Neu5Gc in broader contexts. However, prior preparations of such antibodies (including our own suffered from some non-specificity, as well as some cross-reactivity with the human sialic acid N-acetylneuraminic acid (Neu5Ac.We have developed a novel affinity method utilizing sequential columns of immobilized human and chimpanzee serum sialoglycoproteins, followed by specific elution from the latter column by free Neu5Gc. The resulting mono-specific antibody shows no staining in tissues or cells from mice with a human-like defect in Neu5Gc production. It allows sensitive and specific detection of Neu5Gc in all underlying glycan structural contexts studied, and is applicable to immunohistochemical, enzyme-linked immunosorbent assay (ELISA, Western blot and flow cytometry analyses. Non-immune chicken IgY is used as a reliable negative control. We show that these approaches allow sensitive detection of Neu5Gc in human tissue samples and in some biotherapeutic products, and finally show an example of how Neu5Gc might be eliminated from such products, by using a human cell

Interactive network analysis of the plasma amino acids profile in a mouse model of hyperglycemia

OpenAIRE

Tanaka, Takayuki; Mochida, Taiga; Maki, Yukihiro; Shiraki, Yasuko; Mori, Hiroko; Matsumoto, Shirou; Shimbo, Kazutaka; Ando, Toshihiko; Nakamura, Kimitoshi; Endo, Fumio; Okamoto, Masahiro

2013-01-01

Amino acids are a group of metabolites that are important substrates for protein synthesis, are important as signaling molecules and play central roles as highly connected metabolic hubs, and therefore, there are many reports that describe disease-specific abnormalities in plasma amino acids profile. However, the causes of progression from a healthy control to a manifestation of the plasma amino acid changes remain obscure. Here, we extended the plasma amino acids profile to relationships tha...

Key mediators of intracellular amino acids signaling to mTORC1 activation.

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Duan, Yehui; Li, Fengna; Tan, Kunrong; Liu, Hongnan; Li, Yinghui; Liu, Yingying; Kong, Xiangfeng; Tang, Yulong; Wu, Guoyao; Yin, Yulong

2015-05-01

Mammalian target of rapamycin complex 1 (mTORC1) is activated by amino acids to promote cell growth via protein synthesis. Specifically, Ras-related guanosine triphosphatases (Rag GTPases) are activated by amino acids, and then translocate mTORC1 to the surface of late endosomes and lysosomes. Ras homolog enriched in brain (Rheb) resides on this surface and directly activates mTORC1. Apart from the presence of intracellular amino acids, Rag GTPases and Rheb, other mediators involved in intracellular amino acid signaling to mTORC1 activation include human vacuolar sorting protein-34 (hVps34) and mitogen-activating protein kinase kinase kinase kinase-3 (MAP4K3). Those molecular links between mTORC1 and its mediators form a complicate signaling network that controls cellular growth, proliferation, and metabolism. Moreover, it is speculated that amino acid signaling to mTORC1 may start from the lysosomal lumen. In this review, we discussed the function of these mediators in mTORC1 pathway and how these mediators are regulated by amino acids in details.

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

DEFF Research Database (Denmark)

Thomsen, Martin Christen Frølund; Nielsen, Morten

2012-01-01

Seq2Logo is a web-based sequence logo generator. Sequence logos are a graphical representation of the information content stored in a multiple sequence alignment (MSA) and provide a compact and highly intuitive representation of the position-specific amino acid composition of binding motifs, active...... related to amino acid enrichment and depletion. Besides allowing input in the format of peptides and MSA, Seq2Logo accepts input as Blast sequence profiles, providing easy access for non-expert end-users to characterize and identify functionally conserved/variable amino acids in any given protein...... sites, etc. in biological sequences. Accurate generation of sequence logos is often compromised by sequence redundancy and low number of observations. Moreover, most methods available for sequence logo generation focus on displaying the position-specific enrichment of amino acids, discarding the equally...

The why and how of amino acid analytics in cancer diagnostics and therapy.

Science.gov (United States)

Manig, Friederike; Kuhne, Konstantin; von Neubeck, Cläre; Schwarzenbolz, Uwe; Yu, Zhanru; Kessler, Benedikt M; Pietzsch, Jens; Kunz-Schughart, Leoni A

2017-01-20

Pathological alterations in cell functions are frequently accompanied by metabolic reprogramming including modifications in amino acid metabolism. Amino acid detection is thus integral to the diagnosis of many hereditary metabolic diseases. The development of malignant diseases as metabolic disorders comes along with a complex dysregulation of genetic and epigenetic factors affecting metabolic enzymes. Cancer cells might transiently or permanently become auxotrophic for non-essential or semi-essential amino acids such as asparagine or arginine. Also, transformed cells are often more susceptible to local shortage of essential amino acids such as methionine than normal tissues. This offers new points of attacking unique metabolic features in cancer cells. To better understand these processes, highly sensitive methods for amino acid detection and quantification are required. Our review summarizes the main methodologies for amino acid detection with a particular focus on applications in biomedicine and cancer, provides a historical overview of the methodological pre-requisites in amino acid analytics. We compare classical and modern approaches such as the combination of gas chromatography and liquid chromatography with mass spectrometry (GC-MS/LC-MS). The latter is increasingly applied in clinical routine. We therefore illustrate an LC-MS workflow for analyzing arginine and methionine as well as their precursors and analogs in biological material. Pitfalls during protocol development are discussed, but LC-MS emerges as a reliable and sensitive tool for the detection of amino acids in biological matrices. Quantification is challenging, but of particular interest in cancer research as targeting arginine and methionine turnover in cancer cells represent novel treatment strategies. Copyright © 2016 Elsevier B.V. All rights reserved.

Synthesis and anticonvulsant activity of novel bicyclic acidic amino acids

DEFF Research Database (Denmark)

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

2003-01-01

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

Standardization of formulations for the acute amino acid depletion and loading tests.

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Badawy, Abdulla A-B; Dougherty, Donald M

2015-04-01

The acute tryptophan depletion and loading and the acute tyrosine plus phenylalanine depletion tests are powerful tools for studying the roles of cerebral monoamines in behaviour and symptoms related to various disorders. The tests use either amino acid mixtures or proteins. Current amino acid mixtures lack specificity in humans, but not in rodents, because of the faster disposal of branched-chain amino acids (BCAAs) by the latter. The high content of BCAA (30-60%) is responsible for the poor specificity in humans and we recommend, in a 50g dose, a control formulation with a lowered BCAA content (18%) as a common control for the above tests. With protein-based formulations, α-lactalbumin is specific for acute tryptophan loading, whereas gelatine is only partially effective for acute tryptophan depletion. We recommend the use of the whey protein fraction glycomacropeptide as an alternative protein. Its BCAA content is ideal for specificity and the absence of tryptophan, tyrosine and phenylalanine render it suitable as a template for seven formulations (separate and combined depletion or loading and a truly balanced control). We invite the research community to participate in standardization of the depletion and loading methodologies by using our recommended amino acid formulation and developing those based on glycomacropeptide. © The Author(s) 2015.

Amino acid derived 1,4-dialkyl substituted imidazolones

DEFF Research Database (Denmark)

Diness, Frederik; Meldal, Morten Peter

2010-01-01

A general method for synthesis of 1,4-substituted imidazolones from amino acids on solid support or in solution has been developed. Amino acid derived 3-Boc-(1,3)-oxazinane (Box) protected amino aldehyde building blocks were coupled through urea bonds to the amino terminal of dipeptides or amino...... acids. Upon acidic release, the aldehyde instantaneously formed the cyclic N-carbamyliminium ion, which rearranged to the corresponding imidazolone. Under strongly acidic conditions the imidazolones acted as nuclophiles in the Pictet-Spengler reaction....

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

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Sasabe, Jumpei; Suzuki, Masataka

2018-05-22

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

Nickel Deficiency Disrupts Metabolism of Ureides, Amino Acids, and Organic Acids of Young Pecan Foliage[OA

Science.gov (United States)

Bai, Cheng; Reilly, Charles C.; Wood, Bruce W.

2006-01-01

The existence of nickel (Ni) deficiency is becoming increasingly apparent in crops, especially for ureide-transporting woody perennials, but its physiological role is poorly understood. We evaluated the concentrations of ureides, amino acids, and organic acids in photosynthetic foliar tissue from Ni-sufficient (Ni-S) versus Ni-deficient (Ni-D) pecan (Carya illinoinensis [Wangenh.] K. Koch). Foliage of Ni-D pecan seedlings exhibited metabolic disruption of nitrogen metabolism via ureide catabolism, amino acid metabolism, and ornithine cycle intermediates. Disruption of ureide catabolism in Ni-D foliage resulted in accumulation of xanthine, allantoic acid, ureidoglycolate, and citrulline, but total ureides, urea concentration, and urease activity were reduced. Disruption of amino acid metabolism in Ni-D foliage resulted in accumulation of glycine, valine, isoleucine, tyrosine, tryptophan, arginine, and total free amino acids, and lower concentrations of histidine and glutamic acid. Ni deficiency also disrupted the citric acid cycle, the second stage of respiration, where Ni-D foliage contained very low levels of citrate compared to Ni-S foliage. Disruption of carbon metabolism was also via accumulation of lactic and oxalic acids. The results indicate that mouse-ear, a key morphological symptom, is likely linked to the toxic accumulation of oxalic and lactic acids in the rapidly growing tips and margins of leaflets. Our results support the role of Ni as an essential plant nutrient element. The magnitude of metabolic disruption exhibited in Ni-D pecan is evidence of the existence of unidentified physiological roles for Ni in pecan. PMID:16415214

Protein synthesis in the presence of carbamoyl-amino acids

International Nuclear Information System (INIS)

Kraus, L.M.; Stephens, M.C.

1987-01-01

The role of exogenous carbamoyl-amino acids in protein biosynthesis has been examined in vitro using a mixture of 14 C amino acids to label newly synthesized protein in human reticulocyte rich (8-18%) peripheral blood. Aliquots of the radiolabeled newly synthesized protein were acid precipitated, washed and the radioactivity measured. Control samples which measured the synthetic capacity of the blood were aliquots of the same blood- 14 C amino acid mixture without added carbamoyl-amino acids or cyanate. N-carbamoyl leucine alone or a 3 N-carbamoyl amino acid mixture of leucine, aspartic acid and tyrosine were used to test inhibition of protein synthesis. Also carbamoyl-amino acids were synthesized using cyanate and Pierce hydrolyzate amino acid calibration standards or the mixture of 14 C amino acids. In this system the carbamoylation of endogenous amino acids by cyanate up to 8 μmol/100μl showed a linear decrease in protein synthesis with time which is inversely related to the cyanate concentration. At greater cyanate levels the inhibition of protein synthesis reaches a plateau. When N-carbamoyl-amino acids only are present there is about a 50% decrease in the 14 C protein at 30 minutes as compared to the synthesis of 14 C protein without N-carbamoyl-amino acids. These results indicate that the presence of carbamoyl-amino acids interferes with protein synthesis

Paramagnetic relaxation enhancement of membrane proteins by incorporation of the metal-chelating unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA)

Energy Technology Data Exchange (ETDEWEB)

Park, Sang Ho; Wang, Vivian S.; Radoicic, Jasmina; Angelis, Anna A. De; Berkamp, Sabrina; Opella, Stanley J., E-mail: sopella@ucsd.edu [University of California, San Diego, Department of Chemistry and Biochemistry (United States)

2015-04-15

The use of paramagnetic constraints in protein NMR is an active area of research because of the benefits of long-range distance measurements (>10 Å). One of the main issues in successful execution is the incorporation of a paramagnetic metal ion into diamagnetic proteins. The most common metal ion tags are relatively long aliphatic chains attached to the side chain of a selected cysteine residue with a chelating group at the end where it can undergo substantial internal motions, decreasing the accuracy of the method. An attractive alternative approach is to incorporate an unnatural amino acid that binds metal ions at a specific site on the protein using the methods of molecular biology. Here we describe the successful incorporation of the unnatural amino acid 2-amino-3-(8-hydroxyquinolin-3-yl)propanoic acid (HQA) into two different membrane proteins by heterologous expression in E. coli. Fluorescence and NMR experiments demonstrate complete replacement of the natural amino acid with HQA and stable metal chelation by the mutated proteins. Evidence of site-specific intra- and inter-molecular PREs by NMR in micelle solutions sets the stage for the use of HQA incorporation in solid-state NMR structure determinations of membrane proteins in phospholipid bilayers.

Evolution of amino acid metabolism inferred through cladistic analysis.

Science.gov (United States)

Cunchillos, Chomin; Lecointre, Guillaume

2003-11-28

Because free amino acids were most probably available in primitive abiotic environments, their metabolism is likely to have provided some of the very first metabolic pathways of life. What were the first enzymatic reactions to emerge? A cladistic analysis of metabolic pathways of the 16 aliphatic amino acids and 2 portions of the Krebs cycle was performed using four criteria of homology. The analysis is not based on sequence comparisons but, rather, on coding similarities in enzyme properties. The properties used are shared specific enzymatic activity, shared enzymatic function without substrate specificity, shared coenzymes, and shared functional family. The tree shows that the earliest pathways to emerge are not portions of the Krebs cycle but metabolisms of aspartate, asparagine, glutamate, and glutamine. The views of Horowitz (Horowitz, N. H. (1945) Proc. Natl. Acad. Sci. U. S. A. 31, 153-157) and Cordón (Cordón, F. (1990) Tratado Evolucionista de Biologia, Aguilar, Madrid, Spain), according to which the upstream reactions in the catabolic pathways and the downstream reactions in the anabolic pathways are the earliest in evolution, are globally corroborated; however, with some exceptions. These are due to later opportunistic connections of pathways (actually already suggested by these authors). Earliest enzymatic functions are mostly catabolic; they were deaminations, transaminations, and decarboxylations. From the consensus tree we extracted four time spans for amino acid metabolism development. For some amino acids catabolism and biosynthesis occurred at the same time (Asp, Glu, Lys, Leu, Ala, Val, Ile, Pro, Arg). For others ultimate reactions that use amino acids as a substrate or as a product are distinct in time, with catabolism preceding anabolism for Asn, Gln, and Cys and anabolism preceding catabolism for Ser, Met, and Thr. Cladistic analysis of the structure of biochemical pathways makes hypotheses in biochemical evolution explicit and parsimonious.

Evolution of proteomes: fundamental signatures and global trends in amino acid compositions

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Yeramian Edouard

2006-12-01

Full Text Available Abstract Background The evolutionary characterization of species and lifestyles at global levels is nowadays a subject of considerable interest, particularly with the availability of many complete genomes. Are there specific properties associated with lifestyles and phylogenies? What are the underlying evolutionary trends? One of the simplest analyses to address such questions concerns characterization of proteomes at the amino acids composition level. Results In this work, amino acid compositions of a large set of 208 proteomes, with significant number of representatives from the three phylogenetic domains and different lifestyles are analyzed, resorting to an appropriate multidimensional method: Correspondence analysis. The analysis reveals striking discrimination between eukaryotes, prokaryotic mesophiles and hyperthemophiles-themophiles, following amino acid usage. In sharp contrast, no similar discrimination is observed for psychrophiles. The observed distributional properties are compared with various inferred chronologies for the recruitment of amino acids into the genetic code. Such comparisons reveal correlations between the observed segregations of species following amino acid usage, and the separation of amino acids following early or late recruitment. Conclusion A simple description of proteomes according to amino acid compositions reveals striking signatures, with sharp segregations or on the contrary non-discriminations following phylogenies and lifestyles. The distribution of species, following amino acid usage, exhibits a discrimination between [high GC]-[high optimal growth temperatures] and [low GC]-[moderate temperatures] characteristics. This discrimination appears to coincide closely with the separation of amino acids following their inferred early or late recruitment into the genetic code. Taken together the various results provide a consistent picture for the evolution of proteomes, in terms of amino acid usage.

Consumption of Diet Containing Free Amino Acids Exacerbates Colitis in Mice

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Adna Luciana Souza

2017-11-01

Full Text Available Dietary proteins can influence the maturation of the immune system, particularly the gut-associated lymphoid tissue, when consumed from weaning to adulthood. Moreover, replacement of dietary proteins by amino acids at weaning has been shown to impair the generation of regulatory T cells in the gut as well as immune activities such as protective response to infection, induction of oral and nasal tolerance as well as allergic responses. Polymeric and elemental diets are used in the clinical practice, but the specific role of intact proteins and free amino acids during the intestinal inflammation are not known. It is plausible that these two dietary nitrogen sources would yield distinct immunological outcomes since proteins are recognized by the immune system as antigens and amino acids do not bind to antigen-recognition receptors but instead to intracellular receptors such as mammalian target of rapamycin (mTOR. In this study, our aim was to evaluate the effects of consumption of an amino acid-containing diet (AA diet versus a control protein-containing diet in adult mice at steady state and during colitis development. We showed that consumption of a AA diet by adult mature mice lead to various immunological changes including decrease in the production of serum IgG as well as increase in the levels of IL-6, IL-17A, TGF-β, and IL-10 in the small and large intestines. It also led to changes in the intestinal morphology, to increase in intestinal permeability, in the number of total and activated CD4+ T cells in the small intestine as well as in the frequency of proliferating cells in the colon. Moreover, consumption of AA diet during and prior to development of dextran sodium sulfate-induced colitis exacerbated gut inflammation. Administration of rapamycin during AA diet consumption prevented colitis exacerbation suggesting that mTOR activation was involved in the effects triggered by the AA diet. Therefore, our study suggests that different

Plant amino acid-derived vitamins: biosynthesis and function.

Science.gov (United States)

Miret, Javier A; Munné-Bosch, Sergi

2014-04-01

Vitamins are essential organic compounds for humans, having lost the ability to de novo synthesize them. Hence, they represent dietary requirements, which are covered by plants as the main dietary source of most vitamins (through food or livestock's feed). Most vitamins synthesized by plants present amino acids as precursors (B1, B2, B3, B5, B7, B9 and E) and are therefore linked to plant nitrogen metabolism. Amino acids play different roles in their biosynthesis and metabolism, either incorporated into the backbone of the vitamin or as amino, sulfur or one-carbon group donors. There is a high natural variation in vitamin contents in crops and its exploitation through breeding, metabolic engineering and agronomic practices can enhance their nutritional quality. While the underlying biochemical roles of vitamins as cosubstrates or cofactors are usually common for most eukaryotes, the impact of vitamins B and E in metabolism and physiology can be quite different on plants and animals. Here, we first aim at giving an overview of the biosynthesis of amino acid-derived vitamins in plants, with a particular focus on how this knowledge can be exploited to increase vitamin contents in crops. Second, we will focus on the functions of these vitamins in both plants and animals (and humans in particular), to unravel common and specific roles for vitamins in evolutionary distant organisms, in which these amino acid-derived vitamins play, however, an essential role.

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

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

2018-03-01

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

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

Science.gov (United States)

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

1974-01-01

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

Chemical composition and ruminal degradation kinetics of crude protein and amino acids, and intestinal digestibility of amino acids from tropical forages

Directory of Open Access Journals (Sweden)

Lidia Ferreira Miranda

2012-03-01

Full Text Available The objective of this research was to determine the chemical composition and ruminal degradation of the crude protein (CP, total and individual amino acids of leaves from tropical forages: perennial soybean (Neonotonia wightii, cassava (Manihot esculenta, leucaena (Leucaena leucocephala and ramie (Boehmeria nivea, and to estimate the intestinal digestibility of the rumen undegradable protein (RUDP and individual amino acids of leaves from the tropical forages above cited, but including pigeon pea (Cajanus cajan. Three nonlactating Holstein cows were used to determine the in situ ruminal degradability of protein and amino acids from leaves (6, 18 and 48 hours of ruminal incubation. For determination of the intestinal digestibility of RUDP, the residue from ruminal incubation of the materials was used for 18 hours. A larger concentration of total amino acids for ramie and smaller for perennial soybean were observed; however, they were very similar in leucaena and cassava. Leucine was the essential amino acid of greater concentration, with the exception of cassava, which exhibited a leucine concentration 40.45% smaller. Ramie showed 14.35 and 22.31% more lysine and methionine, respectively. The intestinal digestibility of RUDP varied from 23.56; 47.87; 23.48; 25.69 and 10.86% for leucaena, perennial soybean, cassava, ramie and pigeon pea, respectively. The individual amino acids of tropical forage disappeared in different extensions in the rumen. For the correct evaluation of those forages, one should consider their composition of amino acids, degradations and intestinal digestibility, once the amino acid composition of the forage does not reflect the amino acid profiles that arrived in the small intestine. Differences between the degradation curves of CP and amino acids indicate that degradation of amino acids cannot be estimated through the degradation curve of CP, and that amino acids are not degraded in a similar degradation profile.

Turkey-hen amino acid composition of brain and eyes

International Nuclear Information System (INIS)

Adeyeye, E.I.

2015-01-01

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

Free amino acid pools in muscle and hemolymph during the molt cycle of the land crab, Gecarcinus lateralis

Energy Technology Data Exchange (ETDEWEB)

Yamaoka, L.H.; Skinner, D.M.

1976-01-01

The total free amino acids in muscle water of the land crab, Gecarcinus lateralis, decrease almost 3-fold during the premolt period in comparison to the intermolt period (193 ..mu..M/g during intermolt and 67 ..mu..M/g during late premolt). This decrease is accounted for primarily by changes in the nonessential amino acids proline, glycine and alanine. At the same stage, several essential amino acids (lysine, methionine and tyrosine) increase 2- to 4-fold. Although free amino acid levels in hemolymph are lower and more variable than those in muscle, the same amino acids show similar molt-stage-related changes. The decreases in glycine and proline may be associated with the synthesis of the new exoskeleton and connective tissue during the premolt period.

Methods for preparation of deuterated amino acids

International Nuclear Information System (INIS)

Pshenichnikova, A.B.; Karnaukhova, E.N.; Zvonkova, E.N.

1995-01-01

The current state and prospects for the use of amino acids labeled with stable isotopes are considered. Methods for the preparation of deuterated amino acids, including synthetic, chemicoenzymatic, and biosynthetic ones, and deuterium exchange reactions are summarized. Problems in the preparation of optically pure amino acids are discussed. 120 refs., 15 figs

A GC-ECD method for estimation of free and bound amino acids, gamma-aminobutyric acid, salicylic acid, and acetyl salicylic acid from Solanum lycopersicum (L.).

Science.gov (United States)

Meher, Hari Charan; Gajbhiye, Vijay T; Singh, Ghanendra

2011-01-01

A gas chromatograph with electron capture detection method for estimation of selected metabolites--amino acids (free and bound), gamma-aminobutyric acid (GABA), salicylic acid (SA), and acetyl salicylic acid (ASA) from tomato--is reported. The method is based on nitrophenylation of the metabolites by 1-fluoro-2, 4-dinitrobenzene under aqueous alkaline conditions to form dinitophenyl derivatives. The derivatives were stable under the operating conditions of GC. Analysis of bound amino acids comprised perchloric acid precipitation of protein, alkylation (carboxymethylation) with iodoacetic acid, vapor-phase hydrolysis, and derivatization with 1-fluoro-2,4-dinitrobenzene in that order. The metabolites were resolved in 35 min, using a temperature-programmed run. The method is rapid, sensitive, and precise. It easily measured the typical amino acids (aspartate, asparagine, glutamate, glutamine, alanine, leucine, lysine, and phenylalanine) used for identification and quantification of a protein, resolved amino acids of the same mass (leucine and isoleucine), satisfactorily measured sulfur amino acid (methionine, cystine, and cysteine), and quantified GABA, SA, and ASA, as well. The developed method was validated for specificity, linearity, and precision. It has been applied and recommended for estimation of 25 metabolites from Solanum lycopersicum (L.).

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

International Nuclear Information System (INIS)

Aronu, Ugochukwu E.; Hartono, Ardi; Svendsen, Hallvard F.

2012-01-01

Highlights: ► Density of amino acid salt and amine amino acid salt. ► Viscosity of amino acid salt and amine amino acid salt. ► Henry’s law constant/N 2 O solubility of amino acid salt and amine amino acid salt. ► Schumpe model. Correlations for density, viscosity, and N 2 O solubility. - Abstract: Physicochemical properties of aqueous amino acid salt (AAS), potassium salt of sarcosine (KSAR) and aqueous amine amino acid salt (AAAS), 3-(methylamino)propylamine/sarcosine (SARMAPA) have been studied. Densities of KSAR were measured for sarcosine mole fraction 0.02 to 0.25 for temperature range 298.15 K to 353.15 K, the viscosities were measured for 0.02 to 0.10 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.10 mole fraction sarcosine solutions (298.15 K to 363.15 K). Densities of SARMAPA were measured for sarcosine mole fraction 0.02 to 0.23 for temperature range (298.15 K to 353.15 K), viscosities were measured for 0.02 to 0.16 mole fraction sarcosine (293.15 K to 343.15 K) while the N 2 O solubilities were measured from 0.02 to 0.16 mole fraction sarcosine solutions (298.15 K to 343.15 K). Experimental results were correlated well with empirical correlations and N 2 O solubility results for KSAR were predicted adequately by a Schumpe model. The solubilities of N 2 O in AAS and AAAS are significantly lower than values for amines. The solubilities vary as: amine > AAAS > AAS.

A Soluble, Folded Protein without Charged Amino Acid Residues

DEFF Research Database (Denmark)

Højgaard, Casper; Kofoed, Christian; Espersen, Roall

2016-01-01

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

Amino acid chirality breaking by N-phosphorylation

International Nuclear Information System (INIS)

Zhao Yufen; Yan Qingjin.

1995-01-01

The chirality breaking of amino acid is a focus issue in the origin of life. For chemists, there are some interesting chemical approaches to solve the symmetry breaking problem. Our previous experiments indicated that when amino acids were phosphorylated, there were many bio-mimic reactions happened. In this paper, it was found that there had significant difference between the N-phosphoryl L- and D- amino acids such as serine and threonine. The optical rotation tracing experiments of the racemic N-phosphoamino acids also showed the similar results. The chirality breaking of amino acids by N-phosphorylation was a novel phenomena. (author). 3 refs, 1 fig. Abstract only

The long and winding road: transport pathways for amino acids in Arabidopsis seeds.

Science.gov (United States)

Karmann, Julia; Müller, Benedikt; Hammes, Ulrich Z

2018-03-16

certain plants, e.g., legumes as a resource to support the growth of the seedling after germination. The support of the embryo depends on transport processes that occur between the mother plant and the seed tissues including the embryo. In this review, we will focus on the processes of unloading amino acids from the phloem and their post-phloem transport. We will further highlight similarities between amino acid transport and the transport of the main assimilate and osmolyte, sucrose. Finally, we will discuss similarities and differences between different plant species in terms of structural aspects but for the molecular aspects we are almost exclusively focusing on Arabidopsis. Fig. 1 Vascularization of the Arabidopsis ovule and seed. Plants expressing ER-localized mCherry under control of the companion cell-specific SUC2 promoter and ER-localized GFP under control of the sieve element marker PD1 as described (Müller et al. 2015) are shown to visualize the phloem in the funiculus and the chalazal regions. a Overview over an ovule. FG: female gametophyte. b A magnification of the region marked by a square in panel a. c Overview over a seed. ES: endosperm; E: embryo. d A magnification of the region marked by a square in panel c. The arrows in b and d point to the terminal companion cell and arrowheads to terminal sieve elements.

Amino Acids from a Comet

Science.gov (United States)

Cook, Jamie Elisla

2009-01-01

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

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

Science.gov (United States)

Miki, Yuta; Okazaki, Seiji; Asano, Yasuhisa

2017-05-01

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

Effects of pre-meal drinks with protein and amino acids on glycemic and metabolic responses at a subsequent composite meal

DEFF Research Database (Denmark)

Gunnerud, Ulrika J; Heinzle, Cornelia; Holst, Jens Juul

2012-01-01

Whey proteins have insulinogenic properties and the effect appears to originate from a specific postprandial plasma amino acid pattern. The insulinogenic effect can be mimicked by a specific mixture of the five amino acids iso, leu, lys, thr and val.......Whey proteins have insulinogenic properties and the effect appears to originate from a specific postprandial plasma amino acid pattern. The insulinogenic effect can be mimicked by a specific mixture of the five amino acids iso, leu, lys, thr and val....

ToF-SIMS and principal component analysis of lipids and amino acids from inflamed and dysplastic human colonic mucosa.

Science.gov (United States)

Urbini, Marco; Petito, Valentina; de Notaristefani, Francesco; Scaldaferri, Franco; Gasbarrini, Antonio; Tortora, Luca

2017-10-01

Here, time of flight secondary ion mass spectrometry (ToF-SIMS) and multivariate analysis were combined to study the role of ulcerative colitis (UC), a type of inflammatory bowel disease (IBD), in the colon cancer progression. ToF-SIMS was used to obtain mass spectra and chemical maps from the mucosal surface of human normal (NC), inflamed (IC), and dysplastic (DC) colon tissues. Chemical mapping with a lateral resolution of ≈ 1 μm allowed to evaluate zonation of fatty acids and amino acids as well as the morphological condition of the intestinal glands. High mass resolution ToF-SIMS spectra showed chemical differences in lipid and amino acid composition as a function of pathological state. In positive ion mode, mono- (MAG), di- (DAG), and triacylglycerol (TAG) signals were detected in NC tissues, while in IC and DC tissues, the only cholesterol was present as lipid class representative. Signals from fatty acids, collected in negative ion mode, were subjected to principal component analysis (PCA). PCA showed a strict correlation between IC and DC samples, due to an increase of stearic, arachidonic, and linoleic acid. In the same way, differences in the amino acid composition were highlighted through multivariate analysis. PCA revealed that glutamic acid, leucine/isoleucine, and valine fragments are related to IC tissues. On the other hand, tyrosine, methionine, and tryptophan peaks contributed highly to the separation of DC tissues. Finally, a classification of NC, IC, and DC patients was also achieved through hierarchical cluster analysis of amino acid fragments. In this case, human colonic inflammation showed a stronger relationship with normal than dysplastic condition. Graphical Abstract ᅟ.

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

Science.gov (United States)

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

2012-10-01

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

Production of a new D-amino acid oxidase from the fungus Fusarium oxysporum.

Science.gov (United States)

Gabler, M; Fischer, L

1999-08-01

The fungus Fusarium oxysporum produced a D-amino acid oxidase (EC 1. 4.3.3) in a medium containing glucose as the carbon and energy source and ammonium sulfate as the nitrogen source. The specific D-amino acid oxidase activity was increased up to 12.5-fold with various D-amino acids or their corresponding derivatives as inducers. The best inducers were D-alanine (2.7 microkat/g of dry biomass) and D-3-aminobutyric acid (2.6 microkat/g of dry biomass). The addition of zinc ions was necessary to permit the induction of peroxisomal D-amino acid oxidase. Bioreactor cultivations were performed on a 50-liter scale, yielding a volumetric D-amino acid oxidase activity of 17 microkat liter(-1) with D-alanine as an inducer. Under oxygen limitation, the volumetric activity was increased threefold to 54 microkat liter(-1) (3,240 U liter(-1)).

Amino acid specificity of fibers of the facial/trigeminal complex innervating the maxillary barbel in the Japanese sea catfish, Plotosus japonicus.

Science.gov (United States)

Caprio, John; Shimohara, Mami; Marui, Takayuki; Kohbara, Jun; Harada, Shuitsu; Kiyohara, Sadao

2015-12-01

The Japanese sea catfish, Plotosus japonicus, possesses taste and solitary chemoreceptor cells (SCCs) located on the external body surface that detect specific water-soluble substances. Here, we identify two major fiber types of the facial/trigeminal complex that transmit amino acid information to the medulla. Both single and few fiber preparations respond to amino acid stimulation in the 0.1 μM to mM range. One fiber type responds best to glycine and l-alanine (i.e. Gly/Ala fibers) whereas the other fiber type is best stimulated by l-proline and glycine betaine (hereafter referred to only as betaine) (i.e. Pro/Bet fibers). We demonstrate that betaine, which does not alter the pH of the seawater and therefore does not activate the animals' highly sensitive pH sensors (Caprio et al., Science 344:1154-1156, 2014), is sufficient to elicit appetitive food search behavior. We further show that the amino acid specificity of fibers of the facial/trigeminal complex in P. japonicus is different from that in Ariopsis felis (Michel and Caprio, J. Neurophysiol. 66:247-260, 1991; Michel et al., J. Comp. Physiol. A. 172:129-138, 1993), a representative member of the only other family (Ariidae) of extant marine catfishes. Copyright © 2015 Elsevier Inc. All rights reserved.

α-Amino acid containing degradable polymers as functional biomaterials: rational design, synthetic pathway, and biomedical applications.

Science.gov (United States)

Sun, Huanli; Meng, Fenghua; Dias, Aylvin A; Hendriks, Marc; Feijen, Jan; Zhong, Zhiyuan

2011-06-13

Currently, biomedical engineering is rapidly expanding, especially in the areas of drug delivery, gene transfer, tissue engineering, and regenerative medicine. A prerequisite for further development is the design and synthesis of novel multifunctional biomaterials that are biocompatible and biologically active, are biodegradable with a controlled degradation rate, and have tunable mechanical properties. In the past decades, different types of α-amino acid-containing degradable polymers have been actively developed with the aim to obtain biomimicking functional biomaterials. The use of α-amino acids as building units for degradable polymers may offer several advantages: (i) imparting chemical functionality, such as hydroxyl, amine, carboxyl, and thiol groups, which not only results in improved hydrophilicity and possible interactions with proteins and genes, but also facilitates further modification with bioactive molecules (e.g., drugs or biological cues); (ii) possibly improving materials biological properties, including cell-materials interactions (e.g., cell adhesion, migration) and degradability; (iii) enhancing thermal and mechanical properties; and (iv) providing metabolizable building units/blocks. In this paper, recent developments in the field of α-amino acid-containing degradable polymers are reviewed. First, synthetic approaches to prepare α-amino acid-containing degradable polymers will be discussed. Subsequently, the biomedical applications of these polymers in areas such as drug delivery, gene delivery and tissue engineering will be reviewed. Finally, the future perspectives of α-amino acid-containing degradable polymers will be evaluated.

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

Science.gov (United States)

Ziegler, Jörg; Abel, Steffen

2014-12-01

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

Unnatural reactive amino acid genetic code additions

Energy Technology Data Exchange (ETDEWEB)

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

2017-10-25

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.

Preferential Treatment: Interaction Between Amino Acids and Minerals

Science.gov (United States)

Crapster-Pregont, E. J.; Cleaves, H. J.; Hazen, R. M.

2008-12-01

Amino acids are the building blocks of proteins and are important for some models of the origin of life. Polymerization of amino acids from dilute solution is unlikely without a scaffold or catalyst. The surfaces of early Earth minerals are the most likely candidates for this role. The surface adsorption behavior of 12 amino acids (L-alanine, L-serine, L-aspartic acid, L-proline, L- phenylalanine, L-valine, L-arginine, d-amino valeric acid, glycine, L-lysine, L-isoleucine, and B-alanine) on 21 minerals (quartz, calcite, enstatite, illite, olivine, pyrrhotite, pyrite, alkali basalt, albite, analcime, chlorite, barite, hydroxyl apatite, hematite, magnetite, aluminum hydroxide, kaolin, silica gel, corundum, rutile, and montmorillonite) was determined via batch adsorption experiments. Absorption was determined for concentrations between 10-4M and 10-6M in the presence of 0.1M NaCl, and between pH values of 3 and 9 at 25 degrees C. The equilibrated solutions were centrifuged, filtered, derivatized using a fluorescent amino group tag (dansyl-chloride) and analyzed by HPLC. Adsorption was standardized using BET surface area measurements for each mineral to give the number of mols of each amino acid adsorbed per square meter for each mineral. The results indicate an enormous difference in the adsorption of amino acids between minerals, along with major differences in the adsorption of individual amino acids on the same mineral surface. There is also a change in the absorbance of amino acids as the pH changes. Many previous studies of amino acid concentration and catalysis by minerals have used clay minerals because of their high surface areas, however, this data suggests that the surfaces of minerals such as calcite, quartz and pyrite have even higher affinities for amino acids. The results suggest mineral surfaces that could be optimal locations for the polymerization of molecules linked to the origin of life.

Amino Acid Availability Modulates Vacuolar H+-ATPase Assembly*

Science.gov (United States)

Stransky, Laura A.; Forgac, Michael

2015-01-01

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

Amino acids analysis by total neutron cross-sections determinations: part V

International Nuclear Information System (INIS)

Voi, Dante L.; Ferreira, Francisco de O.; Rocha, Helio F. da

2013-01-01

Total neutron cross-sections of twenty essential and non-essential amino acids to human were determined using crystal spectrometer installed on the Argonauta reactor of IEN (Instituto de Engenharia Nuclear (CNEN-RJ) and compared with data generated by parceling and grouping methodologies developed at this institution. For each amino acid was calculated the respective neutron cross-section by molecular structure, conformation and chemistry analysis. The results obtained for eighteen of twenty amino acids confirm the specifications and product formulations indicated by manufactures. These initial results allow to build a neutron cross-sections database as part of quality control of the amino supplied to hospitals for production of nutriments for parenteral or enteral formulations used in critical patients dependent on artificial feed, and for application in future studies of structure and dynamics for more complex molecules, including proteins, enzymes, fatty acids, membranes, organelles and other cell components. (author)

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

International Nuclear Information System (INIS)

Marchini, J.S.

1992-01-01

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

A Novel Bifunctional Amino Acid Racemase With Multiple Substrate Specificity, MalY From Lactobacillus sakei LT-13: Genome-Based Identification and Enzymological Characterization

Directory of Open Access Journals (Sweden)

Shiro Kato

2018-03-01

addition, Tyr123 was a catalytic residue in the amino acid racemase reaction but strongly affected β-lyase activity. These results showed that Ls-MalY is a novel bifunctional amino acid racemase with multiple substrate specificity; both the amino acid racemase and β-lyase reactions of Ls-MalY were catalyzed at the same active site.

Effect of the essential amino acids upon inclusion in vitro of 14C-phenylalanine and 14C-leucine in the protein of mammary gland

International Nuclear Information System (INIS)

Alexandrov, S.; Ivanov, N.; Sirakov, L.

1983-01-01

It is admitted that the essential amino acids could be divided into two groups, depending on the need of them for synthesis of milk protein: group i - amino acids, which are absorbed in quantities precisely corresponding to their content in milk protein (methionine, phenyl-alanine, histidine, thyrosine and triptophane), and group ii - amino acids, which are absorbed in quantities greater than their content in milk protein and which, because of this, could fullfil other metabolic functions in the mammary gland (threonine, valine, isoleucine, lysine and arginine). According to this concept, tissue slices of lactating mammary gland of guinea-pigs were incubated in the presence of grour i or group ii essential amino acids. Slices were incubated for 60 min at 37+-0.5 deg C, In a Crebs-Ringer phosphate buffer plus 0.2 glucose and 3.7 KBq/ml incubation medium DL-(I- 14 C)-phenylalanine or L-(U- 14 C)-leucine and their incorporation in the tissue proteins of mammary gland was measured in vitro. Group ii essential amino acids provoked significantly more intensive (P<0.001) inclusion in protein synthesis of these labelled amino acids in the tissue of mammary gland, as compared with group i essential amino acids

Thyroid Hormone Effects on Whole-Body Energy Homeostasis and Tissue-Specific Fatty Acid Uptake in Vivo

NARCIS (Netherlands)

Klieverik, Lars P.; Coomans, Claudia P.; Endert, Erik; Sauerwein, Hans P.; Havekes, Louis M.; Voshol, Peter J.; Rensen, Patrick C. N.; Romijn, Johannes A.; Kalsbeek, Andries; Fliers, Eric

2009-01-01

The effects of thyroid hormone (TH) status on energy metabolism and tissue-specific substrate supply in vivo are incompletely understood. To study the effects of TH status on energy metabolism and tissue-specific fatty acid (FA) fluxes, we used metabolic cages as well as C-14-labeled FA and

Alterations in amino acid levels in mouse brain regions after adjunctive treatment of brexpiprazole with fluoxetine: comparison with (R)-ketamine.

Science.gov (United States)

Ma, Min; Ren, Qian; Fujita, Yuko; Yang, Chun; Dong, Chao; Ohgi, Yuta; Futamura, Takashi; Hashimoto, Kenji

2017-11-01

Brexpiprazole, a serotonin-dopamine activity modulator, is approved in the USA as an adjunctive therapy to antidepressants for treating major depressive disorders. Similar to the N-methyl-D-aspartate receptor (NMDAR) antagonist ketamine, the combination of brexpiprazole and fluoxetine has demonstrated antidepressant-like effects in animal models of depression. The present study was conducted to examine whether the combination of brexpiprazole and fluoxetine could affect the tissue levels of amino acids [glutamate, glutamine, γ-aminobutyric acid (GABA), D-serine, L-serine, and glycine] that are associated with NMDAR neurotransmission. The tissue levels of amino acids in the frontal cortex, striatum, hippocampus, and cerebellum were measured after a single [or repeated (14 days)] oral administration of vehicle, fluoxetine (10 mg/kg), brexpiprazole (0.1 mg/kg), or a combination of the two drugs. Furthermore, we measured the tissue levels of amino acids after a single administration of the NMDAR antagonist (R)-ketamine. A single injection of the combination of fluoxetine and brexpiprazole significantly increased GABA levels in the striatum, the D-serine/L-serine ratio in the frontal cortex, and the glycine/L-serine ratio in the hippocampus. A repeated administration of the combination significantly altered the tissue levels of amino acids in all regions. Interestingly, a repeated administration of the combination significantly decreased the D-serine/L-serine ratio in the frontal cortex, striatum, and hippocampus. In contrast, a single administration of (R)-ketamine significantly increased the D-serine/L-serine ratio in the frontal cortex. These results suggested that alterations in the tissue levels of these amino acids may be involved in the antidepressant-like effects of the combination of brexpiprazole and fluoxetine.

Side Chain Cyclized Aromatic Amino Acids

DEFF Research Database (Denmark)

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

2016-01-01

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

D:L-AMINO Acids and the Turnover of Microbial Biomass

Science.gov (United States)

Lomstein, B. A.; Braun, S.; Mhatre, S. S.; Jørgensen, B. B.

2015-12-01

Decades of ocean drilling have demonstrated wide spread microbial life in deep sub-seafloor sediment, and surprisingly high microbial cell numbers. Despite the ubiquity of life in the deep biosphere, the large community sizes and the low energy fluxes in the vast buried ecosystem are still poorly understood. It is not know whether organisms of the deep biosphere are specifically adapted to extremely low energy fluxes or whether most of the observed cells are in a maintenance state. Recently we developed and applied a new culture independent approach - the D:L-amino acid model - to quantify the turnover times of living microbial biomass, microbial necromass and mean metabolic rates. This approach is based on the built-in molecular clock in amino acids that very slowly undergo chemical racemization until they reach an even mixture of L- and D- forms, unless microorganisms spend energy to keep them in the L-form that dominates in living organisms. The approach combines sensitive analyses of amino acids, the unique bacterial endospore marker (dipicolinic acid) with racemization dynamics of stereo-isomeric amino acids. Based on a heating experiment, we recently reported kinetic parameters for racemization of aspartic acid, glutamic acid, serine and alanine in bulk sediment from Aarhus Bay, Denmark. The obtained racemization rate constants were faster than the racemization rate constants of free amino acids, which we have previously applied in Holocene sediment from Aarhus Bay and in up to 10 mio yr old sediment from ODP Leg 201. Another important input parameter for the D:L-amino acid model is the cellular carbon content. It has recently been suggested that the cellular carbon content most likely is lower than previously thought. In recognition of these new findings, previously published data based on the D:L-amino acid model were recalculated and will be presented together with new data from an Arctic Holocene setting with constant sub-zero temperatures.

Death of Lactobacillus acidophilus caused by incorporated /sup 3/H-thymine during incubation without amino acids

Energy Technology Data Exchange (ETDEWEB)

Koukalova, B [Ceskoslovenska Akademie Ved, Brno. Biofysikalni Ustav

1976-01-01

If the cells of Lactobacillus acidophilus R-26 incorporated /sup 3/H-thymine (specific radioactivity 1.57 Ci/mmol or 3.15 Ci/mmol), their transfer to a medium without essential amino acids resulted in their death. This death may result from cell damage caused by the disintegration of tritium which cannot be effectively repaired under conditions of amino acid deprivation. Experimental conditions make it possible to explain this death either as a result of the inhibition of protein or RNA synthesis, or of the absence of amino acids. These possibilities were tested in experiments, in which the synthesis of proteins and RNA was inhibited by specific inhibitors in the presence of amino acids. Under these conditions no death of cells was detected, thus indicating that free amino acids are important in the repair of radiation damage.

Amino acids in the cultivation of mammalian cells.

Science.gov (United States)

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

2016-05-01

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

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

Science.gov (United States)

Gao, Xiuzhen; Ma, Qinyuan; Zhu, Hailiang

2015-04-01

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

Amino Acid Catabolism in Multiple Sclerosis Affects Immune Homeostasis.

Science.gov (United States)

Negrotto, Laura; Correale, Jorge

2017-03-01

Amino acid catabolism has been implicated in immunoregulatory mechanisms present in several diseases, including autoimmune disorders. Our aims were to assess expression and activity of enzymes involved in Trp and Arg catabolism, as well as to investigate amino acid catabolism effects on the immune system of multiple sclerosis (MS) patients. To this end, 40 MS patients, 30 healthy control subjects, and 30 patients with other inflammatory neurological diseases were studied. Expression and activity of enzymes involved in Trp and Arg catabolism (IDO1, IDO2, Trp 2,3-dioxygenase [TDO], arginase [ARG] 1, ARG2, inducible NO synthetase) were evaluated in PBMCs. Expression of general control nonrepressed 2 serine/threonine kinase and mammalian target of rapamycin (both molecules involved in sensing amino acid levels) was assessed in response to different stimuli modulating amino acid catabolism, as were cytokine secretion levels and regulatory T cell numbers. The results demonstrate that expression and activity of IDO1 and ARG1 were significantly reduced in MS patients compared with healthy control subjects and other inflammatory neurological diseases. PBMCs from MS patients stimulated with a TLR-9 agonist showed reduced expression of general control nonrepressed 2 serine/threonine kinase and increased expression of mammalian target of rapamycin, suggesting reduced amino acid catabolism in MS patients. Functionally, this reduction resulted in a decrease in regulatory T cells, with an increase in myelin basic protein-specific T cell proliferation and secretion of proinflammatory cytokines. In contrast, induction of IDO1 using CTLA-4 or a TLR-3 ligand dampened proinflammatory responses. Overall, these results highlight the importance of amino acid catabolism in the modulation of the immunological responses in MS patients. Molecules involved in these pathways warrant further exploration as potential new therapeutic targets in MS. Copyright © 2017 by The American Association of

Studies on radiolysis of amino acids, (3)

International Nuclear Information System (INIS)

Oku, Tadatake

1978-01-01

For the purpose of investigating the radiolysis of amino acids and the safeness to radiation, the radiolytic mechanism and radio-sensitivity of sulfur-containing amino acids in aqueous solution in the presence of air or in the atmosphere of nitrogen were studied. Aqueous solutions of L-methionine, cysteine (both 1mM) and L-cystine (0.3mM) were irradiated with γ-ray of 60 Co at the dose of 4.2 - 2,640 x 10 3 rad. The amino acids and the radiolytic products were determined with an amino acid analyzer. The volatile sulfur compounds formed from γ-irradiated methionine were estimated by a flame photometric detector-gas chromatograph. From the results obtained, G values of the radiolysis of sulfur-containing amino acids and the products were calculated, and the radiolytic mechanisms of methionine, cysteine and cystine were proposed. The radio-sensitivity of sulfur-containing amino acids was shown as follows: cysteine (C3-SH) > methionine (C5, -SCH 3 ) > cystine (C 6 , -S-S-). Off-flavor development from γ-irradiated methionine when oxidizing agent was added was less than that when reducing agent was added. (Kobatake, H.)

Degradation of fructans and production of propionic acid by Bacteroides thetaiotaomicron are enhanced by shortage of amino acids

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Signe eAdamberg

2014-12-01

Full Text Available Bacteroides thetaiotaomicron is commonly found in the human colon and stabilizes its ecosystem by the catabolism of various polysaccharides. A model of cross-talk between the metabolism of amino acids and fructans in B. thetaiotaomicron was proposed. The growth of B. thetaiotaomicron DSM 2079 in two defined media containing mineral salts and vitamins, and supplemented with either 20 or 2 amino acids, was studied in an isothermal microcalorimeter. The polyfructans inulin (from chicory and levan (synthesized using levansucrase from Pseudomonas syringae, two fructooligosaccharide preparations with different composition, sucrose and fructose were tested as substrates. The calorimetric power-time curves were substrate specific and typically multiauxic. A surplus of amino acids reduced the consumption of longer oligosaccharides (DP > 3. Bacterial growth was not detected either in the carbohydrate free medium containing amino acids or in the medium with inulin as a sole carbohydrate. In amino acid-restricted medium, fermentation leading to acetic acid formation was dominant at the beginning of growth (up to 24 h, followed by increased lactic acid production, and mainly propionic and succinic acids were produced at the end of fermentation. In the medium supplemented with 20 amino acids, the highest production of D-lactate (82 ± 33 mmol/gDW occurred in parallel with extensive consumption (up to 17 mmol/gDW of amino acids, especially Ser, Thr and Asp. The production of Ala and Glu was observed at growth on all substrates, and the production was enhanced under amino acid deficiency. The study revealed the influence of amino acids on fructan metabolism in B. thetaiotaomicron and showed that defined growth media are invaluable in elucidating quantitative metabolic profiles of the bacteria. Levan was shown to act as an easily degradable substrate for B. thetaiotaomicron. The effect of levan on balancing or modifying colon microbiota will be studied in

Distribution of α-aminoisobutyric acid in tissues of lean and genetically obese mice

International Nuclear Information System (INIS)

Tews, J.K.; Harper, A.E.

1989-01-01

Distribution of tracer amounts of the nonmetabolizable neutral amino acid α-[1- 14 C]aminoisobutyric acid (AIB) between blood and several tissues was measured in lean and ob/ob mice over an 8-hr period. As AIB was injected on the basis of body weight and as ob/ob mice have a relatively low blood volume, absolute concentrations of AIB in blood and tissues were almost always higher in the obese than the lean mice. However, the ratio of AIB concentration in the tissues to that in the blood was clearly higher in skeletal muscle, diaphragm, and brain, and possibly higher in liver of the lean than of the obese animals. Ratios in heart were similar. The results suggest that lean and genetically obese mice differ in their capacity to transport amino acids between blood and various tissues

Tunable translational control using site-specific unnatural amino acid incorporation in Escherichia coli

Directory of Open Access Journals (Sweden)

Yusuke Kato

2015-04-01

Full Text Available Translation of target gene transcripts in Escherichia coli harboring UAG amber stop codons can be switched on by the amber-codon-specific incorporation of an exogenously supplied unnatural amino acid, 3-iodo-L-tyrosine. Here, we report that this translational switch can control the translational efficiency at any intermediate magnitude by adjustment of the 3-iodo-L-tyrosine concentration in the medium, as a tunable translational controller. The translational efficiency of a target gene reached maximum levels with 10−5 M 3-iodo-L-tyrosine, and intermediate levels were observed with suboptimal concentrations (approximately spanning a 2-log10 concentration range, 10−7–10−5 M. Such intermediate-level expression was also confirmed in individual bacteria.

Dynamics of human whole body amino acid metabolism

International Nuclear Information System (INIS)

Young, V.R.

1981-01-01

The mechanism of regulation of the nitrogen metabolism in humans under various nutritional and physiological states was examined using stable isotopes. In the simultaneous continuous infusion of 1- [ 13 ] - leucine and α- [ 15 N]- lysine, their fluxed decreased when individuals received lower protein intake. The rates of oxidation and incorporation into body proteins of leucine changed in parallel with the protein intake. Such effects of diet on whole body leucine kinetics were modified by the energy state and dietary energy level. The nitrogen balance was also improved by an excess level of dietary energy. When the intake of dietary protein was lowered below the maintenance level, the whole body flux and de novo synthesis of glycine were lowered, but alanine synthesis was clearly increased. The intravenous infusion of glucose at 4 mg/kg.min, which causes increase in excess blood sugar and plasma insulin, increased the alanine flux, but had no effect on the glycine flux. The rate of albumin synthesis, determined by giving 15 N-glycine orally every 3 hr, decreased with the lowered intake of dietary protein in young men, but not in elderly men. This explains why the serum albumin synthesis increases with the increase in the intake of dietary protein in young men, but not in elderly men. The rate of whole body protein synthesis in young men receiving the L-amino acid diets providing with the required intake of specific amino acid was much lower than that in the men receiving the diets providing with generous intake of specific amino acid. Thus the control mechanism to maintain the homeostasis of body nitrogen and amino acids is related in some unknown way to the nutritional requirement of the hosts. (Kaihara, S.)

A new treatment for human malignant melanoma targeting L-type amino acid transporter 1 (LAT1): A pilot study in a canine model

International Nuclear Information System (INIS)

Fukumoto, Shinya; Hanazono, Kiwamu; Fu, Dah-Renn; Endo, Yoshifumi; Kadosawa, Tsuyoshi; Iwano, Hidetomo; Uchide, Tsuyoshi

2013-01-01

Highlights: •LAT1 is highly expressed in tumors but at low levels in normal tissues. •We examine LAT1 expression and function in malignant melanoma (MM). •LAT1 expression in MM tissues and cell lines is higher than those in normal tissues. •LAT1 selective inhibitors inhibit amino acid uptake and cell growth in MM cells. •New chemotherapeutic protocols including LAT1 inhibitors are effective for treatment. -- Abstract: L-type amino acid transporter 1 (LAT1), an isoform of amino acid transport system L, transports branched or aromatic amino acids essential for fundamental cellular activities such as cellular growth, proliferation and maintenance. This amino acid transporter recently has received attention because of its preferential and up-regulated expression in a variety of human tumors in contrast to its limited distribution and low-level expression in normal tissues. In this study, we explored the feasibility of using LAT1 inhibitor as a new therapeutic agent for human malignant melanomas (MM) using canine spontaneous MM as a model for human MM. A comparative study of LAT expression was performed in 48 normal tissues, 25 MM tissues and five cell lines established from MM. The study observed LAT1 mRNA levels from MM tissues and cell lines that were significantly (P 3 H]L-Leucine uptake and cellular growth activities in CMeC-1 were inhibited in a dose-dependent manner by selective LAT1 inhibitors (2-amino-2-norbornane-carboxylic acid, BCH and melphalan, LPM). Inhibitory growth activities of various conventional anti-cancer drugs, including carboplatin, cyclophosphamide, dacarbazine, doxorubicin, mitoxantrone, nimustine, vinblastine and vincristine, were significantly (P < 0.05) enhanced by combination use with BCH or LPM. These findings suggest that LAT1 could be a new therapeutic target for MM

Scaffolding along Nucleic Acid Duplexes Using 2'-Amino-Locked Nucleic Acids

DEFF Research Database (Denmark)

Astakhova, I Kira; Wengel, Jesper

2014-01-01

-LNA nucleotides. By application of different chemical reactions, modification of 2'-amino-LNA scaffolds can be efficiently performed in high yields and with various tags, postsynthetically or during the automated oligonucleotide synthesis. The choice of a synthetic method for scaffolding along 2'-amino-LNA mainly....../DNA probes bind nucleic acid targets with advantages of high affinity and specificity. Thus, molecular motion of nanodevices and programmable self-assembly of chemically modified LNA/DNA nanomaterials can be followed by bright fluorescence signaling from the functionalized LNA units. Another appealing aspect...

Amino acids transport in lactic streptococci

NARCIS (Netherlands)

Driessen, Arnold Jacob Mathieu

1987-01-01

Lactic streptococci are extremely fastidious bacteria. For growth an exogenous source of amino acids and other nutrients is essential. The amino acid requirement in milk is fulfilled by the milk-protein casein, which is degraded by sequential hydrolysis, involving proteases and peptidases. ... Zie:

Genetic analysis of amino acid transport in the facultatively heterotrophic cyanobacterium Synechocystis sp. Strain 6803

International Nuclear Information System (INIS)

Labarre, J.; Thuriaux, P.; Chauvat, F.

1987-01-01

The existence of active transport systems (permeases) operating on amino acids in the photoautotrophic cyanobacterium Synechocystis sp. strain 6803 was demonstrated by following the initial rates of uptake with 14 C-labeled amino acids, measuring the intracellular pools of amino acids, and isolating mutants resistant to toxic amino acids. One class of mutants (Pfa1) corresponds to a regulatory defect in the biosynthesis of the aromatic amino acids, but two other classes (Can1 and Aza1) are defective in amino acid transport. The Can1 mutants are defective in the active transport of three basic amino acids (arginine, histidine, and lysine) and in one of two transport systems operating on glutamine. The Aza1 mutants are not affected in the transport of the basic amino acids but have lost the capacity to transport all other amino acids except glutamate. The latter amino acid is probably transported by a third permease which could be identical to the Can1-independent transport operating on glutamine. Thus, genetic evidence suggests that strain 6803 has only a small number of amino acid transport systems with fairly broad specificity and that, with the exception of glutamine, each amino acid is accumulated by only one major transport system. Compared with heterotrophic bacteria such as Escherichia coli, these permeases are rather inefficient in terms of affinity (apparent K/sub m/ ranging from 6 to 60 μM) and of V/sub max/

Contributions of molecular size, charge distribution, and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates.

Science.gov (United States)

Sun, Na; Cui, Pengbo; Jin, Ziqi; Wu, Haitao; Wang, Yixing; Lin, Songyi

2017-09-01

This study investigated the contributions of molecular size, charge distribution and specific amino acids to the iron-binding capacity of sea cucumber (Stichopus japonicus) ovum hydrolysates (SCOHs), and further explored their iron-binding sites. It was demonstrated that enzyme type and degree of hydrolysis (DH) significantly influenced the iron-binding capacity of the SCOHs. The SCOHs produced by alcalase at a DH of 25.9% possessed the highest iron-binding capacity at 92.1%. As the hydrolysis time increased, the molecular size of the SCOHs decreased, the negative charges increased, and the hydrophilic amino acids were exposed to the surface, facilitating iron binding. Furthermore, the Fourier transform infrared spectra, combined with amino acid composition analysis, revealed that iron bound to the SCOHs primarily through interactions with carboxyl oxygen of Asp, guanidine nitrogen of Arg or nitrogen atoms in imidazole group of His. The formed SCOHs-iron complexes exhibited a fold and crystal structure with spherical particles. Copyright © 2017 Elsevier Ltd. All rights reserved.

Isolation of 14C labelled amino acids by biosynthesis in maize plants (Zea mais L.)

International Nuclear Information System (INIS)

Carreras, N.; Mazon, M.P.

1983-01-01

A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 C O2 produced from Ba 14 C O3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic column (Dowex 50-X4). (Author) 56 refs

Isolation of carbon 14 labelled amino acids by biosynthesis in maize plants (zea mais L.)

International Nuclear Information System (INIS)

Carreras, N.; Mazon, M.P.

1983-01-01

A method of obtaining 14 C labelled amino acids by biosynthesis in maize plants which had assimilated 14 CO 2 , has been assayed. The plants were labelled for 60 minutes with 14 CO 2 produced from Ba 14 CO 3 (specific activity of 148 KBq/μmol). An extract of the soluble compounds was obtained with 80% ethanol and the amino acids were separated from the rest of the soluble compounds by ion exchange chromatography on column of Dowex 50-X8 resin. Finally, seventeen amino acids were isolated and identified from the purified extract. The acid amino acids were separated in anionic column (Dowex 1-X8) and the neutral and basic amino acids in cationic columns (Dowex 50-X4). (author)

The single-biopsy approach in determining protein synthesis in human slow-turning-over tissue: use of flood-primed, continuous infusion of amino acid tracer

DEFF Research Database (Denmark)

Holm, Lars; Reitelseder, Søren; Dideriksen, Kasper

2014-01-01

Muscle protein synthesis (MPS) rate is determined conventionally by obtaining two or more tissue biopsies during a primed, continuous infusion of a stable isotopically labeled amino acid. The purpose of the present study was to test whether tracer priming given as a flooding dose, thereby securing....... In conclusion, the flood-primed, continuous infusion protocol using phenylalanine as tracer can validly be used to measure the protein synthesis rate in human in vivo experiments by obtaining only a single tissue biopsy after a prolonged infusion period....

omega-Amino acid:pyruvate transaminase from Alcaligenes denitrificans Y2k-2: a new catalyst for kinetic resolution of beta-amino acids and amines.

Science.gov (United States)

Yun, Hyungdon; Lim, Seongyop; Cho, Byung-Kwan; Kim, Byung-Gee

2004-04-01

Alcaligenes denitrificans Y2k-2 was obtained by selective enrichment followed by screening from soil samples, which showed omega-amino acid:pyruvate transaminase activity, to kinetically resolve aliphatic beta-amino acid, and the corresponding structural gene (aptA) was cloned. The gene was functionally expressed in Escherichia coli BL21 by using an isopropyl-beta-D-thiogalactopyranoside (IPTG)-inducible pET expression system (9.6 U/mg), and the recombinant AptA was purified to show a specific activity of 77.2 U/mg for L-beta-amino-n-butyric acid (L-beta-ABA). The enzyme converts various beta-amino acids and amines to the corresponding beta-keto acids and ketones by using pyruvate as an amine acceptor. The apparent K(m) and V(max) for L-beta-ABA were 56 mM and 500 U/mg, respectively, in the presence of 10 mM pyruvate. In the presence of 10 mM L-beta-ABA, the apparent K(m) and V(max) for pyruvate were 11 mM and 370 U/mg, respectively. The enzyme exhibits high stereoselectivity (E > 80) in the kinetic resolution of 50 mM D,L-beta-ABA, producing optically pure D-beta-ABA (99% enantiomeric excess) with 53% conversion.

ω-Amino Acid:Pyruvate Transaminase from Alcaligenes denitrificans Y2k-2: a New Catalyst for Kinetic Resolution of β-Amino Acids and Amines

Science.gov (United States)

Yun, Hyungdon; Lim, Seongyop; Cho, Byung-Kwan; Kim, Byung-Gee

2004-01-01

Alcaligenes denitrificans Y2k-2 was obtained by selective enrichment followed by screening from soil samples, which showed ω-amino acid:pyruvate transaminase activity, to kinetically resolve aliphatic β-amino acid, and the corresponding structural gene (aptA) was cloned. The gene was functionally expressed in Escherichia coli BL21 by using an isopropyl-β-d-thiogalactopyranoside (IPTG)-inducible pET expression system (9.6 U/mg), and the recombinant AptA was purified to show a specific activity of 77.2 U/mg for l-β-amino-n-butyric acid (l-β-ABA). The enzyme converts various β-amino acids and amines to the corresponding β-keto acids and ketones by using pyruvate as an amine acceptor. The apparent Km and Vmax for l-β-ABA were 56 mM and 500 U/mg, respectively, in the presence of 10 mM pyruvate. In the presence of 10 mM l-β-ABA, the apparent Km and Vmax for pyruvate were 11 mM and 370 U/mg, respectively. The enzyme exhibits high stereoselectivity (E > 80) in the kinetic resolution of 50 mM d,l-β-ABA, producing optically pure d-β-ABA (99% enantiomeric excess) with 53% conversion. PMID:15066855

Acquisition and evolution of plant pathogenesis-associated gene clusters and candidate determinants of tissue-specificity in xanthomonas.

Directory of Open Access Journals (Sweden)

Hong Lu

Full Text Available Xanthomonas is a large genus of plant-associated and plant-pathogenic bacteria. Collectively, members cause diseases on over 392 plant species. Individually, they exhibit marked host- and tissue-specificity. The determinants of this specificity are unknown.To assess potential contributions to host- and tissue-specificity, pathogenesis-associated gene clusters were compared across genomes of eight Xanthomonas strains representing vascular or non-vascular pathogens of rice, brassicas, pepper and tomato, and citrus. The gum cluster for extracellular polysaccharide is conserved except for gumN and sequences downstream. The xcs and xps clusters for type II secretion are conserved, except in the rice pathogens, in which xcs is missing. In the otherwise conserved hrp cluster, sequences flanking the core genes for type III secretion vary with respect to insertion sequence element and putative effector gene content. Variation at the rpf (regulation of pathogenicity factors cluster is more pronounced, though genes with established functional relevance are conserved. A cluster for synthesis of lipopolysaccharide varies highly, suggesting multiple horizontal gene transfers and reassortments, but this variation does not correlate with host- or tissue-specificity. Phylogenetic trees based on amino acid alignments of gum, xps, xcs, hrp, and rpf cluster products generally reflect strain phylogeny. However, amino acid residues at four positions correlate with tissue specificity, revealing hpaA and xpsD as candidate determinants. Examination of genome sequences of xanthomonads Xylella fastidiosa and Stenotrophomonas maltophilia revealed that the hrp, gum, and xcs clusters are recent acquisitions in the Xanthomonas lineage.Our results provide insight into the ancestral Xanthomonas genome and indicate that differentiation with respect to host- and tissue-specificity involved not major modifications or wholesale exchange of clusters, but subtle changes in a small

Lipidization of Simple and di-Functional Amino Acids

International Nuclear Information System (INIS)

Zainab Idris; Mohd Wahid Samsudin; Salmiah Ahmad

2013-01-01

This paper discuss the modification of azelaic acid into its applicable form by attachment of both its carboxyl sites to N-terminal of amino acid ethyl ester forming amide linkages in anhydrous medium. Acylation of glycine ethyl ester hydrochloride with azelaic acid dichloride was best conducted in a 100 % anhydrous medium. L-amino acid ethyl ester bearing a primary hydroxyl group on its side chain gave mixtures of product and variation in composition depending on the mole ratio of reactants used. Reduction in purity was also observed for L-amino acid ethyl ester with primary -SH group on its side chain as compared to L-amino acid ethyl ester having -SCH 3 group on the L-amino acid side chain. The diamidoester of azelaic acid with L-alanine ethyl ester, L-valine ethyl ester, L-leucine ethyl ester and L-glutamic acid diethyl ester were in good yield when prepared through the modified Schotten-Baumann reaction conditions. (author)

Biometrics from the carbon isotope ratio analysis of amino acids in human hair.

Science.gov (United States)

Jackson, Glen P; An, Yan; Konstantynova, Kateryna I; Rashaid, Ayat H B

2015-01-01

This study compares and contrasts the ability to classify individuals into different grouping factors through either bulk isotope ratio analysis or amino-acid-specific isotope ratio analysis of human hair. Using LC-IRMS, we measured the isotope ratios of 14 amino acids in hair proteins independently, and leucine/isoleucine as a co-eluting pair, to provide 15 variables for classification. Multivariate analysis confirmed that the essential amino acids and non-essential amino acids were mostly independent variables in the classification rules, thereby enabling the separation of dietary factors of isotope intake from intrinsic or phenotypic factors of isotope fractionation. Multivariate analysis revealed at least two potential sources of non-dietary factors influencing the carbon isotope ratio values of the amino acids in human hair: body mass index (BMI) and age. These results provide evidence that compound-specific isotope ratio analysis has the potential to go beyond region-of-origin or geospatial movements of individuals-obtainable through bulk isotope measurements-to the provision of physical and characteristic traits about the individuals, such as age and BMI. Further development and refinement, for example to genetic, metabolic, disease and hormonal factors could ultimately be of great assistance in forensic and clinical casework. Copyright © 2014 Forensic Science Society. Published by Elsevier Ireland Ltd. All rights reserved.

Amino acid regulation of autophagosome formation

NARCIS (Netherlands)

Meijer, Alfred J.

2008-01-01

Amino acids are not only substrates for various metabolic pathways, but can also serve as signaling molecules controlling signal transduction pathways. One of these signaling pathways is mTOR-dependent and is activated by amino acids (leucine in particular) in synergy with insulin. Activation of

The incorporation of labelled amino acids into the subcellular fractions of the rabbit brain

International Nuclear Information System (INIS)

Ogrodnik, W.

1980-01-01

Radioactive amino acids were injected into the fourth ventriculum of adult rabbits. After 3, 6 and 13 hours the animals were killed and tissue subcellular fractions were prepared from their brains. Nucleic acids were extracted and quantitatively determined from nucleic, myelin, mitochondrial, microsomal and cytoplasmic fractions. The radioactivity was determined in the protein and nucleic acid fractions. It was found out that the incorporation of radioactive amino acids increased in relation to time. In the analyzed subcellular fractions a very rapid incorporation of glutamic acid and leucine into cytoplasmic proteins was observed. The chromatographic analysis of the nucleic acids showed that radioactivity in the nucleic acid fractions depended on a radioactive protein contamination. Radioactive aminoacyl-tRNA was not found in the nucleic acid fractions, extracted from different subcellular fractions. (author)

Free amino acids and isosmotic intracellular regulation in the shrimp Crangon crangon

NARCIS (Netherlands)

Weber, R.E.; Marrewijk, Willibrordus J. A. van

1972-01-01

The concentrations of non-protein nitrogenous material and individual free amino acids in muscle tissue of the euryhaline shrimp Crangon grancon are measured. The cellular ninhydrin-positive component closely follows blood osmolarity over a range of ambient salinities and temperatures. The three

AMINO ACIDS APPLICATION TO CREATE OF NANOSTRUCTURES

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I. S. Chekman

2014-12-01

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

Amino acid sequence preferences to control cell-specific organization of endothelial cells, smooth muscle cells, and fibroblasts.

Science.gov (United States)

Kanie, Kei; Kato, Ryuji; Zhao, Yingzi; Narita, Yuji; Okochi, Mina; Honda, Hiroyuki

2011-06-01

Effective surface modification with biocompatible molecules is known to be effective in reducing the life-threatening risks related to artificial cardiovascular implants. In recent strategies in regenerative medicine, the enhancement and support of natural repair systems at the site of injury by designed biocompatible molecules have succeeded in rapid and effective injury repair. Therefore, such a strategy could also be effective for rapid endothelialization of cardiovascular implants to lower the risk of thrombosis and stenosis. To achieve this enhancement of the natural repair system, a biomimetic molecule that mimics proper cellular organization at the implant location is required. In spite of the fact that many reported peptides have cell-attracting properties on material surfaces, there have been few peptides that could control cell-specific adhesion. For the advanced cardiovascular implants, peptides that can mimic the natural mechanism that controls cell-specific organization have been strongly anticipated. To obtain such peptides, we hypothesized the cellular bias toward certain varieties of amino acids and examined the cell preference (in terms of adhesion, proliferation, and protein attraction) of varieties and of repeat length on SPOT peptide arrays. To investigate the role of specific peptides in controlling the organization of various cardiovascular-related cells, we compared endothelial cells (ECs), smooth muscle cells (SMCs), and fibroblasts (FBs). A clear, cell-specific preference was found for amino acids (longer than 5-mer) using three types of cells, and the combinational effect of the physicochemical properties of the residues was analyzed to interpret the mechanism. Copyright © 2011 European Peptide Society and John Wiley & Sons, Ltd.

The Origin of Amino Acids in Lunar Regolith Samples

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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.

Crystalline amino acids and nitrogen emission

NARCIS (Netherlands)

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

2003-01-01

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

21 CFR 172.320 - Amino acids.

Science.gov (United States)

2010-04-01

... 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 § 172.320 Amino acids. The food additive amino acids may be safely used...

Effects of squat exercise and branched-chain amino acid supplementation on plasma free amino acid concentrations in young women.

Science.gov (United States)

Shimomura, Yoshiharu; Kobayashi, Hisamine; Mawatari, Kazunori; Akita, Keiichi; Inaguma, Asami; Watanabe, Satoko; Bajotto, Gustavo; Sato, Juichi

2009-06-01

The present study was conducted to examine alterations in plasma free amino acid concentrations induced by squat exercise and branched-chain amino acid (BCAA) supplementation in young, untrained female subjects. In the morning on the exercise session day, participants ingested drinks containing either BCAA (isoleucine:leucine:valine=1:2.3:1.2) or dextrin (placebo) at 0.1 g/kg body weight 15 min before a squat exercise session, which consisted of 7 sets of 20 squats, with 3 min intervals between sets. In the placebo trial, plasma BCAA concentrations were decreased subsequent to exercise, whereas they were significantly increased in the BCAA trial until 2 h after exercise. Marked changes in other free amino acids in response to squat exercise and BCAA supplementation were observed. In particular, plasma concentrations of methionine and aromatic amino acids were temporarily decreased in the BCAA trial, being significantly lower than those in the placebo trial. These results suggest that BCAA intake before exercise affects methionine and aromatic amino acid metabolism.

Penguin Proxies: Deciphering Millennial-Scale Antarctic Ecosystem Change using Amino Acid Stable Isotope Analysis.

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Michelson, C.; McMahon, K.; Emslie, S. D.; Patterson, W. P.; McCarthy, M. D.; Polito, M. J.

2017-12-01

The Southern Ocean ecosystem is undergoing rapid environmental change due to ongoing and historic anthropogenic impacts such as climate change and marine mammal harvesting. These disturbances may have cascading effects through the Antarctic food webs, resulting in profound shifts in the sources and cycling of organic matter supporting higher-trophic organisms, such as penguins. For example, bulk stable isotope analyses of modern and ancient preserved penguin tissues suggest variations in penguin feeding ecology throughout the Holocene with dramatic isotopic shifts in the last 200 years. However, it is not clear whether these isotopic shifts resulted from changes at the base of the food web, dietary shifts in penguins, or some combination of both factors. Newly developed compound-specific stable nitrogen isotope analysis of individual amino acids (CSIA-AA) may provide a powerful new tool to tease apart these confounding variables. Stable nitrogen isotope values of trophic amino acids (e.g., glutamic acid) increase substantially with each trophic transfer in the food web, while source amino acid (e.g., phenylalanine) stable nitrogen isotope values remain relatively unchanged and reflect ecosystem baselines. As such, we can use this CSIA-AA approach to decipher between baseline and dietary shifts in penguins over time from modern and ancient eggshells of Pygoscelis penguins in the Antarctic Peninsula and the Ross Sea regions of Antarctica. In order to accurately apply this CSIA-AA approach, we first characterized the trophic fractionation factors of individual amino acids between diet and penguin consumers in a long-term controlled penguin feeding experiment. We then applied these values to modern and ancient eggshells from the Antarctic Peninsula and Ross Sea to evaluate shifts in penguin trophic dynamics as a function of climate and anthropogenic interaction throughout much of the Holocene. This work develops a cutting edge new molecular geochemistry approach

CodonTest: modeling amino acid substitution preferences in coding sequences.

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Wayne Delport

2010-08-01

Full Text Available Codon models of evolution have facilitated the interpretation of selective forces operating on genomes. These models, however, assume a single rate of non-synonymous substitution irrespective of the nature of amino acids being exchanged. Recent developments have shown that models which allow for amino acid pairs to have independent rates of substitution offer improved fit over single rate models. However, these approaches have been limited by the necessity for large alignments in their estimation. An alternative approach is to assume that substitution rates between amino acid pairs can be subdivided into rate classes, dependent on the information content of the alignment. However, given the combinatorially large number of such models, an efficient model search strategy is needed. Here we develop a Genetic Algorithm (GA method for the estimation of such models. A GA is used to assign amino acid substitution pairs to a series of rate classes, where is estimated from the alignment. Other parameters of the phylogenetic Markov model, including substitution rates, character frequencies and branch lengths are estimated using standard maximum likelihood optimization procedures. We apply the GA to empirical alignments and show improved model fit over existing models of codon evolution. Our results suggest that current models are poor approximations of protein evolution and thus gene and organism specific multi-rate models that incorporate amino acid substitution biases are preferred. We further anticipate that the clustering of amino acid substitution rates into classes will be biologically informative, such that genes with similar functions exhibit similar clustering, and hence this clustering will be useful for the evolutionary fingerprinting of genes.

The scaled-charge additive force field for amino acid based ionic liquids

DEFF Research Database (Denmark)

Fileti, E. E.; Chaban, V. V.

2014-01-01

Ionic liquids (ILs) constitute an emerging research field. New ILs involve more and more organic and inorganic ions. Amino acid based ILs (AAILs) represent a specific interest due to their evolutional connection to proteins. We report a new non-polarizable force field (FF) for the eight AAILs...... comprising 1-ethyl-3-methylimidazolium cation and amino acid anions. The anions were obtained via deprotonation of carboxyl group. Specific cation-anion non-covalent interactions were taken into account by computing electrostatic potential for ion pairs. The van der Waals interactions were adopted from...

Commercial laying hen diets formulated according to different recommendations of total and digestible amino acids

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EM Casartelli

2005-09-01

Full Text Available An experiment was conducted to evaluate different commercial laying hen diets formulated based on recommendations for total and digestible amino acids. One hundred and twenty Lohmann LSL commercial laying hens aged 25 weeks were distributed in a completely randomized experimental design involving five replications of six birds in four treatments. Diet formulation on a total amino acid basis followed the recommendations of NRC (1994 and Rostagno et al. (2000, whereas formulation on digestible amino acids basis was according to Rostagno et al. (2000 and Degussa (1997 recommendations. The experimental period was divided into five periods of fourteen days. Performance parameters (egg production, feed intake, feed conversion, egg mass were evaluated for each period, and on the last two days of each period, three eggs per replication were collected to evaluate egg quality parameters (Haugh unit, egg specific gravity, egg weight, eggshell thickness and percentage. Means were compared by orthogonal contrasts. Results on feed intake, egg production, egg mass, feed conversion and egg specific gravity showed that total amino acid recommendations promoted better bird responses than digestible amino acid recommendations.

Degradation of protein translation machinery by amino acid starvation-induced macroautophagy

DEFF Research Database (Denmark)

Gretzmeier, Christine; Eiselein, Sven; Johnson, Gregory R.

2017-01-01

, unbiased approaches relying on quantitative mass spectrometry-based proteomics. Macroautophagy is induced by rapamycin treatment, and by amino acid and glucose starvation in differentially, metabolically labeled cells. Protein dynamics are linked to image-based models of autophagosome turnover. Depending...... on the inducing stimulus, protein as well as organelle turnover differ. Amino acid starvation-induced macroautophagy leads to selective degradation of proteins important for protein translation. Thus, protein dynamics reflect cellular conditions in the respective treatment indicating stimulus-specific pathways...

iSNO-PseAAC: predict cysteine S-nitrosylation sites in proteins by incorporating position specific amino acid propensity into pseudo amino acid composition.

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Yan Xu

Full Text Available Posttranslational modifications (PTMs of proteins are responsible for sensing and transducing signals to regulate various cellular functions and signaling events. S-nitrosylation (SNO is one of the most important and universal PTMs. With the avalanche of protein sequences generated in the post-genomic age, it is highly desired to develop computational methods for timely identifying the exact SNO sites in proteins because this kind of information is very useful for both basic research and drug development. Here, a new predictor, called iSNO-PseAAC, was developed for identifying the SNO sites in proteins by incorporating the position-specific amino acid propensity (PSAAP into the general form of pseudo amino acid composition (PseAAC. The predictor was implemented using the conditional random field (CRF algorithm. As a demonstration, a benchmark dataset was constructed that contains 731 SNO sites and 810 non-SNO sites. To reduce the homology bias, none of these sites were derived from the proteins that had [Formula: see text] pairwise sequence identity to any other. It was observed that the overall cross-validation success rate achieved by iSNO-PseAAC in identifying nitrosylated proteins on an independent dataset was over 90%, indicating that the new predictor is quite promising. Furthermore, a user-friendly web-server for iSNO-PseAAC was established at http://app.aporc.org/iSNO-PseAAC/, by which users can easily obtain the desired results without the need to follow the mathematical equations involved during the process of developing the prediction method. It is anticipated that iSNO-PseAAC may become a useful high throughput tool for identifying the SNO sites, or at the very least play a complementary role to the existing methods in this area.

Absorption of proteins and amino acids

International Nuclear Information System (INIS)

Jeejeebhoy, K.N.

1976-01-01

Although the absorption of proteins and amino acids is an important issue in nutrition, its measurement is not common because of the methodological difficulties. Complications are attributable in particular to the magnitude of endogenous protein secretion and to the diversity of absorption mechanisms for amino acids either as individual units or as peptides. Methods for studying absorption include balance techniques, tolerance tests, tracer techniques using proteins or amino acids labelled with 131 I, 3 H, or 15 N, intestinal perfusion studies, and others; they must be selected according to the nature of the information sought. Improvements over the current methods would be useful. (author)

The Role of Microbial Amino Acid Metabolism in Host Metabolism

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Evelien P. J. G. Neis

2015-04-01

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

A new treatment for human malignant melanoma targeting L-type amino acid transporter 1 (LAT1): A pilot study in a canine model

Energy Technology Data Exchange (ETDEWEB)

Fukumoto, Shinya; Hanazono, Kiwamu [Veterinary Internal Medicine, Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan); Fu, Dah-Renn; Endo, Yoshifumi; Kadosawa, Tsuyoshi [Veterinary Oncology, Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan); Iwano, Hidetomo [Veterinary Biochemistry, Department of Basic Veterinary Medicine, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan); Uchide, Tsuyoshi, E-mail: uchide@rakuno.ac.jp [Veterinary Internal Medicine, Department of Small Animal Clinical Sciences, School of Veterinary Medicine, Rakuno Gakuen University, Ebetsu, Hokkaido 069-8501 (Japan)

2013-09-13

Highlights: •LAT1 is highly expressed in tumors but at low levels in normal tissues. •We examine LAT1 expression and function in malignant melanoma (MM). •LAT1 expression in MM tissues and cell lines is higher than those in normal tissues. •LAT1 selective inhibitors inhibit amino acid uptake and cell growth in MM cells. •New chemotherapeutic protocols including LAT1 inhibitors are effective for treatment. -- Abstract: L-type amino acid transporter 1 (LAT1), an isoform of amino acid transport system L, transports branched or aromatic amino acids essential for fundamental cellular activities such as cellular growth, proliferation and maintenance. This amino acid transporter recently has received attention because of its preferential and up-regulated expression in a variety of human tumors in contrast to its limited distribution and low-level expression in normal tissues. In this study, we explored the feasibility of using LAT1 inhibitor as a new therapeutic agent for human malignant melanomas (MM) using canine spontaneous MM as a model for human MM. A comparative study of LAT expression was performed in 48 normal tissues, 25 MM tissues and five cell lines established from MM. The study observed LAT1 mRNA levels from MM tissues and cell lines that were significantly (P < 0.01) higher than in normal tissues. Additionally, MM with distant metastasis showed a higher expression than those without distant metastasis. Functional analysis of LAT1 was performed on one of the five cell lines, CMeC-1. [{sup 3}H]L-Leucine uptake and cellular growth activities in CMeC-1 were inhibited in a dose-dependent manner by selective LAT1 inhibitors (2-amino-2-norbornane-carboxylic acid, BCH and melphalan, LPM). Inhibitory growth activities of various conventional anti-cancer drugs, including carboplatin, cyclophosphamide, dacarbazine, doxorubicin, mitoxantrone, nimustine, vinblastine and vincristine, were significantly (P < 0.05) enhanced by combination use with BCH or LPM

Wet, Carbonaceous Asteroids: Altering Minerals, Changing Amino Acids

Science.gov (United States)

Taylor, G. J.

2011-04-01

Many carbonaceous chondrites contain alteration products from water-rock interactions at low temperature and organic compounds. A fascinating fact known for decades is the presence in some of them of an assortment of organic compounds, including amino acids, sometimes called the building blocks of life. Murchison and other CM carbonaceous chondrites contain hundreds of amino acids. Early measurements indicated that the amino acids in carbonaceous chondrites had equal proportions of L- and D-structures, a situation called racemic. This was in sharp contrast to life on Earth, which heavily favors L- forms. However, beginning in 1997, John Cronin and Sandra Pizzarello (Arizona State University) found L- excesses in isovaline and several other amino acids in the Murchison carbonaceous chondrite. In 2009, Daniel Glavin and Jason Dworkin (Astrobiology Analytical Lab, Goddard Space Flight Center) reported the first independent confirmation of L-isovaline excesses in Murchison using a different analytical technique than employed by Cronin and Pizzarello. Inspired by this work, Daniel Glavin, Michael Callahan, Jason Dworkin, and Jamie Elsila (Astrobiology Analytical Lab, Goddard Space Flight Center), have done an extensive study of the abundance and symmetry of amino acids in carbonaceous chondrites that experienced a range of alteration by water in their parent asteroids. The results show that amino acids are more abundant in the less altered meteorites, implying that aqueous processing changes the mix of amino acids. They also confirmed the enrichment in L-structures of some amino acids, especially isovaline, confirming earlier work. The authors suggest that aqueously-altered planetesimals might have seeded the early Earth with nonracemic amino acids, perhaps explaining why life from microorganisms to people use only L- forms to make proteins. The initial imbalance caused by non-biologic processes in wet asteroids might have been amplified by life on Earth. Alternatively

Amino acid catabolism and generation of volatiles by lactic acid bacteria.

Science.gov (United States)

Tavaria, F K; Dahl, S; Carballo, F J; Malcata, F X

2002-10-01

Twelve isolates of lactic acid bacteria, belonging to the Lactobacillus, Lactococcus, Leuconostoc, and Enterococcus genera, were previously isolated from 180-d-old Serra da Estrela cheese, a traditional Portuguese cheese manufactured from raw milk and coagulated with a plant rennet. These isolates were subsequently tested for their ability to catabolize free amino acids, when incubated independently with each amino acid in free form or with a mixture thereof. Attempts were made in both situations to correlate the rates of free amino acid uptake with the numbers of viable cells. When incubated individually, leucine, valine, glycine, aspartic acid, serine, threonine, lysine, glutamic acid, and alanine were degraded by all strains considered; arginine tended to build up, probably because of transamination of other amino acids. When incubated together, the degradation of free amino acids by each strain was dependent on pH (with an optimum pH around 6.0). The volatiles detected in ripened Serra da Estrela cheese originated mainly from leucine, phenylalanine, alanine, and valine, whereas in vitro they originated mainly from valine, phenylalanine, serine, leucine, alanine, and threonine. The wild strains tested offer a great potential for flavor generation, which might justify their inclusion in a tentative starter/nonstarter culture for that and similar cheeses.

Incretin effect after oral amino Acid ingestion in humans

DEFF Research Database (Denmark)

Lindgren, Ola; Pacini, Giovanni; Tura, Andrea

2015-01-01

is also present after amino acid ingestion is not known. OBJECTIVE: The objective of the study was to explore insulin secretion and incretin hormones after oral and iv amino acid administration at matched total amino acid concentrations in healthy subjects. DESIGN: An amino acid mixture (Vaminolac......) was administered orally or iv at a rate resulting in matching total amino acid concentrations to 12 male volunteers with age 22.5 ± 1.4 years and a body mass index 22.4 ± 1.4 kg/m(2), who had no history of diabetes. MAIN OUTCOME MEASURES: Main outcome measures were area under the 120-minute curve for insulin, C...... after oral than after iv amino acid challenges (P = .006), whereas there was no significant difference in the glucagon response. Intact and total GIP rose after oral but not after iv amino acid administration, whereas intact and total GLP-1 levels did not change significantly in either test. CONCLUSION...

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

Science.gov (United States)

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

2015-07-21

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