Gamma-Glutamyltransferase 2 (gGT2)

GGT2 belongs to the gamma-glutamyltransferase (GGT) gene family. GGT is a membrane-bound extracellular enzyme that cleaves gamma-glutamyl peptide bonds in glutathione and other peptides and transfers the gamma-glutamyl moiety to acceptors. GGT is also key to glutathione homeostasis because it provides substrates for glutathione synthesis. The confusion between type II GGT mRNA and GGT2 arose from the nonstandardized nomenclature of GGT isoforms, genes, and mRNAs. There is a marked heterogeneity in GGT in human serum and tissues, but this heterogeneity can be attributed to different glycosylation of the same peptide rather than to the products of different genes. Heterogeneity in human serum is also related to association of GGT with various other proteins .