Glutamine (molecular weight: 146.15 g/mol) is one of the 20 amino acids encoded by the 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.
Glutamine is genetically coded for by the RNA codons CAA and CAG. Its three-letter abbreviation is Gln, and its one letter abbreviation is Q.
Glutamine's side chain is neutral in the physiological range of pH, but polar and hydrophilic.
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 which accomplishes this is called glutamine synthetase . Glutamine can then be used as a nitrogen donor in the biosynthesis of many compounds, including other amino acids, purines, and pyrimidines.
Since it can be synthesized from glutamic acid, glutamine is not an essential amino acid.
Some people who believe consuming high levels of glutamic acid (as in MSG) to be harmful also advise caution about glutamine. This view does not have mainstream medical and scientific support.
It has been suggested glutamine is utilized at a higher than normal rate in people living with diseases that strain the immune system, such as HIV. Glutamine is used in the digestive process and a deficiency may contribute to wasting.