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.
A. A. BOLDYREV