Short name: GGT_peptidase
Gamma-glutamyltranspeptidase (EC:126.96.36.199) (GGT) [PMID: 2868390] catalyzes the transfer of the gamma-glutamyl moiety of glutathione to an acceptor that may be an amino acid, a peptide or water (forming glutamate). GGT plays a key role in the gamma-glutamyl cycle, a pathway for the synthesis and degradation of glutathione and drug and xenobiotic detoxification [PMID: 1378736]. In prokaryotes and eukaryotes, it is an enzyme that consists of two polypeptide chains, a heavy and a light subunit, processed from a single chain precursor by an autocatalytic cleavage. The active site of GGT is known to be located in the light subunit. The sequences of mammalian and bacterial GGT show a number of regions of high similarity [PMID: 2570061]. Pseudomonas cephalosporin acylases (EC:3.5.1) that convert 7-beta-(4-carboxybutanamido)-cephalosporanic acid (GL-7ACA) into 7-aminocephalosporanic acid (7ACA) and glutaric acid are evolutionary related to GGT and also show some GGT activity [PMID: 1358202]. Like GGT, these GL-7ACA acylases, are also composed of two subunits.
As an autocatalytic peptidase GGT belongs to MEROPS peptidase family T3 (gamma-glutamyltransferase family, clan PB(T)). The active site residue for members of this family and family T1 is C-terminal to the autolytic cleavage site. The type example is gamma-glutamyltransferase 1 from Escherichia coli.
- PF01019 (G_glu_transpept)
- PTHR11686 (PTHR11686)
- PTHR43199 (PTHR43199)
- PS00462 (G_GLU_TRANSPEPTIDASE)
- PR01210 (GGTRANSPTASE)
- TIGR00066 (g_glut_trans)