glutamine (Gln) /glo̅o̅″təmēn/ [L, gluten + amine, ammonia] , a nonessential amino acid found in the juices of many plants and in many proteins in the body. It functions as an amino donor for many reactions. It is also a nontoxic transport for ammonia because it is readily hydrolyzed to glutamic acid and free ammonia, the latter excreted in the urine. See also amino acid, protein.
