The Enzyme Database

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EC 2.3.2.2     
Accepted name: γ-glutamyltransferase
Reaction: a (5-L-glutamyl)-peptide + an amino acid = a peptide + a 5-L-glutamyl amino acid
Other name(s): glutamyl transpeptidase; α-glutamyl transpeptidase; γ-glutamyl peptidyltransferase; γ-glutamyl transpeptidase (ambiguous); γ-GPT; γ-GT; γ-GTP; L-γ-glutamyl transpeptidase; L-γ-glutamyltransferase; L-glutamyltransferase; GGT (ambiguous); γ-glutamyltranspeptidase (ambiguous)
Systematic name: (5-L-glutamyl)-peptide:amino-acid 5-glutamyltransferase
Comments: The mammlian enzyme is part of the cell antioxidant defense mechanism. It initiates extracellular glutathione (GSH) breakdown, provides cells with a local cysteine supply and contributes to maintain intracelular GSH levels. The protein also has EC 3.4.19.13 (glutathione hydrolase) activity [3-4]. The enzyme consists of two chains that are created by the proteolytic cleavage of a single precursor polypeptide. The N-terminal L-threonine of the C-terminal subunit functions as the active site for both the cleavage and the hydrolysis reactions [3-4].
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, PDB, CAS registry number: 9046-27-9
References:
1.  Goore, M.Y. and Thompson, J.F. γ-Glutamyl transpeptidase from kidney bean fruit. I. Purification and mechanism of action. Biochim. Biophys. Acta 132 (1967) 15–26. [PMID: 6030345]
2.  Leibach, F.H. and Binkley, F. γ-Glutamyl transferase of swine kidney. Arch. Biochem. Biophys. 127 (1968) 292–301. [PMID: 5698023]
3.  Okada, T., Suzuki, H., Wada, K., Kumagai, H. and Fukuyama, K. Crystal structures of γ-glutamyltranspeptidase from Escherichia coli, a key enzyme in glutathione metabolism, and its reaction intermediate. Proc. Natl. Acad. Sci. USA 103 (2006) 6471–6476. [PMID: 16618936]
4.  Boanca, G., Sand, A., Okada, T., Suzuki, H., Kumagai, H., Fukuyama, K. and Barycki, J.J. Autoprocessing of Helicobacter pylori γ-glutamyltranspeptidase leads to the formation of a threonine-threonine catalytic dyad. J. Biol. Chem. 282 (2007) 534–541. [PMID: 17107958]
5.  Wickham, S., West, M.B., Cook, P.F. and Hanigan, M.H. Gamma-glutamyl compounds: substrate specificity of γ-glutamyl transpeptidase enzymes. Anal. Biochem. 414 (2011) 208–214. [PMID: 21447318]
[EC 2.3.2.2 created 1972, modified 1976, modified 2011]
 
 


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