glutamic acid

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glutamic acid

glutamic acid (glo͞otămˈĭk), organic compound, one of the 20 amino acids commonly found in animal proteins. Only the L-stereoisomer occurs in mammalian proteins. Like aspartic acid, glutamic acid has an acidic carboxyl group on its side chain which can serve as both an acceptor and a donor of ammonia, a compound toxic to the body. Once glutamic acid has coupled with ammonia, it is called glutamine and can as such safely transport ammonia to the liver, where the ammonia is eventually converted to urea for excretion by the kidneys. Free glutamic acid (that not incorporated into proteins) can also be converted reversibly to α-ketoglutaric acid, an intermediate in the Krebs cycle, and as such can be degraded to carbon dioxide and water, or transformed into sugars. The acidic side chain of glutamic acid confers one negative charge under most conditions to proteins in which this amino acid is found, thus increasing the water solubility of the protein. Monosodium glutamate (MSG), the monosodium salt of L-glutamic acid, is widely used as a condiment. The amino acid was isolated from wheat gluten in 1866 and chemically synthesized in 1890. It is not essential to the human diet, since it can be synthesized in the body from the common intermediate α-ketoglutaric acid.

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The following article is from The Great Soviet Encyclopedia (1979). It might be outdated or ideologically biased.

Glutamic Acid


an amino acid, COOH—CH2—CH2— CH(NH2)—COOH. Water-soluble crystals. Melting point, 202° C. It is a component of proteins and of a number of important low-molecular-weight compounds (for example, glutathione and folic acid). The natural form is the D(+) isomer. Glutamic acid is a nonessential amino acid for animals. It is contained in large amounts in casein, gelatin, and gluten. Together with the corresponding γ-monoamide, glutamine, it comprises about one-third of the total free amino acids in blood plasma. The reaction glutamic acid + NH3 + ATP ⇌ glutamine + ADP + Pinorg. is catalyzed by the enzyme glutamine synthetase, which belongs to the lyase group. This reaction results in the binding of excess ammonia in animal and vegetable tissues. Thus, glutamine transports ammonia to the site of its detoxification (mostly in the kidneys and liver). Glutamine also serves as an amino-group reserve and is a component of proteins. The glutamine-glutamic-acid system plays a particularly important role in metabolism. Glutamic acid also takes part in other important metabolic processes, such as transamination (where, with as partic acid, it is an invariable participant), in oxidative deamination leading to the formation of α-ketoglutaric acid (which is involved in the tricarboxylic acid cycle), in decarboxylation leading to the formation of the important neurotropic agent γ-aminobutyric acid, and in many syntheses, including glutathione, glucose, and ornithine.

Glutamic acid is utilized in the food industry as a sodium salt for improving the taste and nutritional value of foods. It is used in medicine in tablets, powders, and pastes, as well as in solutions (for intravenous infusion) in the treatment of some mental and nervous diseases. The calcium and magnesium salts of glutamic acid are also prescribed.


The Great Soviet Encyclopedia, 3rd Edition (1970-1979). © 2010 The Gale Group, Inc. All rights reserved.

glutamic acid

[glü′tam·ik ′as·əd]
C5H9O4N A dicarboxylic amino acid of the α-ketoglutaric acid family occurring widely in proteins.
McGraw-Hill Dictionary of Scientific & Technical Terms, 6E, Copyright © 2003 by The McGraw-Hill Companies, Inc.
References in periodicals archive ?
In the case of glutamic acid, as well as salicylic acid, the formation of [Fe.sub.3][O.sub.4]@GLU and [Fe.sub.3][O.sub.4]@SAL leads to the existence of multiple functional groups of the stabilizing agent, therefore allowing additional interactions between these moieties.
(a) Citric (CA) and isocitric (ICA) acids; (b) malic acid (MA); (c) succinic acid (SA); (d) fumaric acid (FA); (e) glutamic acid (GA); (f) lactic acid (LA).
The results obtained (Figure 3) showed that the highest lipopeptides production determined in the culture broth was obtained when a combination of glutamic acid (5 g/L) and yeast extract (1g/L) was used as nitrogen sources.
The ELISA test kit provides a quantitative in vitro assay for human autoantibodies against glutamic acid decarboxylase (GAD) and tyrosine phosphatase (IA2) in serum (EUROIMMUN, Germany).
There are no results in the literature with glutamic acid supplemented in diets with protein reduction involving commercial layers.
Glutamic acid substituted for valine at the seventh position of the alpha chain
Conclusion: Production of glutamic acid using optimized medium minimizes the time needed for designing the medium composition.
In literature the PGA-producing strains are reported to be of two types, either glutamic acid-dependent or independent but ones which are glutamic acid independent PGA producers are adversely affected if glutamic acid or other related components are present in medium [9,10].
Histidine has the highest normalized frequency in binding sites, while glutamic acid has the lowest normalized frequency among those three amino acid residues [1].
The micromolecule substances were [alpha]-glucose, [beta]-glucose, [beta]-hydroxyisobutyric acid, [beta]-hydroxybutyric acid, phenylalanine, alanine, acetone, choline, methionine, dimethylamine, glycine, glutamate methylamine, glutamine, creatine, creatinine, inositol, methylamine, lysine, leucine, tyrosine, hippuric acid, ornithine, taurine, praline, carnitine, lactic acid, tryptophan, threonine, aspartic acid, valine, isoleucine, acetyl glutamic acid, histidine, and N-acetyl glycoprotein.
Analysis of percentage composition of individual amino acids of [beta]-galactosidase at primary structure (Figure 1) revealed that the roles of alanine, valine, arginine, glutamine, glutamic acid, glycine, phenylalanine, serine, threonine, and tyrosine in temperature adaptation were most significant.

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