title: Gamma-glutamyl transpeptidase in transgenic tobacco plants. Cellular localization, processing, and biochemical properties.
abstract: gamma-Glutamyl transpeptidase (gamma-GT) is a ubiquitous enzyme that catalyzes the first step of glutathione (GSH) degradation in the gamma-glutamyl cycle in mammals. A cDNA encoding an Arabidopsis homolog for gamma-GT was overexpressed in tobacco (Nicotiana tabacum) plants. A high level of the membrane-bound gamma-GT activity was localized outside the cell in transgenic plants. The overproduced enzyme was characterized by a high affinity to GSH and was cleaved post-translationally in two unequal subunits. Thus, Arabidopsis gamma-GT is similar to the mammalian enzymes in enzymatic properties, post-translational processing, and cellular localization, suggesting analogous biological functions as a key enzyme in the catabolism of GSH.
authors.affiliation: Vakgroep Moleculaire Genetica, Departement Plantengenetica, Vlaams Interuniversitair Instituut voor Biotechnologie, Universiteit Gent, K.L. Ledeganckstraat 35, B-9000 Gent, Belgium.
authors.forename: Sergei
authors.initials: S
authors.lastname: Storozhenko
authors.forename: Enric
authors.initials: E
authors.lastname: Belles-Boix
authors.forename: Elena
authors.initials: E
authors.lastname: Babiychuk
authors.forename: Didier
authors.initials: D
authors.lastname: Hérouart
authors.forename: Mark W
authors.initials: MW
authors.lastname: Davey
authors.forename: Luit
authors.initials: L
authors.lastname: Slooten
authors.forename: Marc
authors.initials: M
authors.lastname: Van Montagu
authors.forename: Dirk
authors.initials: D
authors.lastname: Inzé
authors.forename: Sergei
authors.initials: S
authors.lastname: Kushnir
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D017360:Arabidopsis / Q000201:enzymology* / Q000235:genetics; D002462:Cell Membrane / Q000201:enzymology; D003001:Cloning, Molecular; D015971:Gene Expression Regulation, Enzymologic; D005978:Glutathione / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D008322:Mammals / Q000235:genetics; D018613:Microscopy, Confocal; D008969:Molecular Sequence Data; D005810:Multigene Family; D018384:Oxidative Stress; D030821:Plants, Genetically Modified; D017386:Sequence Homology, Amino Acid; D014026:Nicotiana / Q000201:enzymology* / Q000235:genetics; D005723:gamma-Glutamyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D005723:gamma-Glutamyltransferase; D005978:Glutathione