- The δ-amide of glutamic acid, derived by oxidation from proline in the liver or by the combination of glutamic acid with ammonia; the l-isomer is present in proteins and in blood and other tissues, and is an important source of urinary ammonia, being broken down in the kidney by the action of the enzyme glutaminase; nonenzymatically, it is converted to 5-oxoproline.- g. aminotransferase an enzyme that reversibly reacts l-g. with α-ketoglutarate to produce α-ketoglutaramate and l-glutamate; α-ketoglutaramate is elevated in certain cases of hepatocoma. SYN: g. transaminase.- g. synthetase an enzyme that catalyzes the reaction of l-glutamic acid, ammonia, and ATP to g., ADP, and orthophosphate; one of the few known mammalian enzymes that uses ammonium ion as a substrate under physiological conditions.- g. transaminase SYN: g. aminotransferase.
* * *glu·ta·mine 'glüt-ə-.mēn n a crystalline amino acid C5H10N2O3 that is found both free and in proteins in plants and animals and that yields glutamic acid and ammonia on hydrolysis abbr. Gln
* * *n.
* * *glu·ta·mine (glooґtə-mēn) [USP] the monoamide of glutamic acid, a nonessential amino acid occurring in the juices of many plants and in some animal tissues; it is an important carrier of urinary ammonia and is broken down in the kidney by the enzyme glutaminase. Symbols Gln and Q. See also table at amino acid.
Medical dictionary. 2011.