title: gamma-Glutamyl transpeptidase: catalytic mechanism and gene expression.
abstract: The gamma-glutamyl transpeptidases are key enzymes in the so-called gamma-glutamyl cycle involving glutathione synthesis, the recovery of its constituents, and in the transport of amino acids. This membrane-bound ectoenzyme thus serves to regulate glutathione synthesis. This chapter deals with the active site chemistry of gamma-glutamyl transpeptidase, including the role of side-chain groups on the light subunit as well as several serine residues in the catalytic process. Also considered are genomic studies indicating (a) the presence of a single gene in mouse and rat; (b) the occurrence of multiple genes in humans; (c) the involvement of multiple promoters for gene expression; and (d) how these multiple promoters may play a role in the tissue-specific expression of gamma-glutamyl transpeptidases.
authors.affiliation: Department of Biochemistry, Osaka University Medical School, Japan.
authors.forename: N
authors.initials: N
authors.lastname: Taniguchi
authors.forename: Y
authors.initials: Y
authors.lastname: Ikeda
mesh_terms: D000595:Amino Acid Sequence; D001665:Binding Sites; D015971:Gene Expression Regulation, Enzymologic; D005978:Glutathione / Q000378:metabolism*; D006801:Humans; D008113:Liver Neoplasms / Q000201:enzymology; D008168:Lung / Q000201:enzymology; D008969:Molecular Sequence Data; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D005723:gamma-Glutamyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005723:gamma-Glutamyltransferase; D005978:Glutathione