DL-Glutamine (Glutamin, 2-amino-4-carbamoylbutanoic acid) is a non-essential amino acid present abundantly throughout the body and is involved in many metabolic processes.
L-Glutamine is important as a precursor for peptide and protein synthesis, amino sugar synthesis, purine and pyrimidine and thus nucleic acid and nucleotide synthesis, as well as providing a source of carbons for oxidation in some cell. Glutamine has been reported to enhance many functional parameters of immune cells such as T-cell proliferation, B-lymphocyte differentiation, macrophage phagocytosis, antigen presentation and cytokine production plus neutrophil superoxide production and apoptosis. Glutamine itself may act as a key precursor for nucleic acids and nucleotides in glutamine-consuming cells, but in many physiological circumstances acts to provide glutamate, which appears to promote a wider array of metabolic functions compared to glutamine[1].
L-Glutamate is the most abundant intracellular amino acid whereas L-glutamine is the most abundant extracellular amino acid in vivo. Glutamine metabolism is zoned in the liver so that glutamine is taken up by the periportal cells of the liver in which there is a relatively high glutaminase activity and the ammonia produced directed towards carbamoyl phosphate synthesis[1].
[1] Newsholme P, et al. Cell Biochem Funct. 2003, 21(1):1-9.