Glutamine is one of the 20 amino acids encoded by the standard genetic code. Its side chain is an amide; it is formed by replacing a side-chain hydroxyl of glutamic acid with an amine functional group.
Formation and Nomenclature
Glutamine is genetically coded for by the RNA codons CAA and CAG. Glutamine's three-letter abbreviation is Gln, and its one-letter abbreviation is Q. A three-letter designation for either glutamine or glutamic acid is Glx (one-letter abbreviation: Z). Like other amino acids, glutamine is biochemically important as a constituent of proteins. Glutamine is also crucial in nitrogen metabolism. Ammonia (formed by nitrogen fixation) is assimilated into organic compounds by converting glutamic acid to glutamine. The enzyme that accomplishes this is called glutamine synthetase. Glutamine can, hence, be used as a nitrogen donor in the biosynthesis of many compounds, including other amino acids, purines, and pyrimidines.
Usage
Glutamine is a supplement that is used in weightlifting and bodybuilding, as well as by those who suffer from muscular cramps [1] or pain—particularly elderly people. The main use of glutamine within the diet of either groups is as a means of replenishing the body's stores of amino acids that have been used during exercise or everyday activities. There are still studies which are looking into problems with excessive consumption of glutamine, which thus far have proved inconclusive. However, normal supplementation is healthy mainly because glutamine is supposed to be supplemented after prolonged periods of exercise (for example, a workout or exercise in which amino acids are required for use) and replenishes amino acid stores; this being the main reason glutamine is recommended during fasting or for people who suffer from physical trauma, immune deficiencies, or cancer.