title: Role of gamma-glutamyltranspeptidase in detoxification of xenobiotics in the yeasts Hansenula polymorpha and Saccharomyces cerevisiae.
abstract: GGT1 gene of the methylotrophic yeast Hansenula polymorpha appears to be a structural and functional homologue of Saccharomyces cerevisiae CIS2/ECM38 gene encoding gamma-glutamyltranspeptidase (gammaGT). This is confirmed by the absence of the corresponding activity of gammaGT in the mutant with disrupted GGT1 gene. It was shown that gammaGT of both H. polymorpha and S. cerevisiae are involved in detoxification of electrophilic xenobiotics, as the corresponding mutants appeared to be defective in the disappearance of the fluorescent vacuolar complex of GSH with xenobiotic bimane and the further diffuse distribution of this complex in the cytosol. We hypothesize that metabolism of electrophilic xenobiotics in the yeasts H. polymorpha and S. cerevisiae occurs through a gammaGT-dependent mercapturic acid pathway of GSH-xenobiotic detoxification, similar to that known for mammalian cells, with cysteine-xenobiotics and/or N-acetylcysteine-xenobiotics as the end products.
authors.affiliation: Institute of Cell Biology, National Academy of Sciences of Ukraine, Drahomanov Street, 14/16, Lviv 79005 Ukraine.
authors.forename: Vira M
authors.initials: VM
authors.lastname: Ubiyvovk
authors.forename: Oleksandra V
authors.initials: OV
authors.lastname: Blazhenko
authors.forename: Daniel
authors.initials: D
authors.lastname: Gigot
authors.forename: Michel
authors.initials: M
authors.lastname: Penninckx
authors.forename: Andriy A
authors.initials: AA
authors.lastname: Sibirny
mesh_terms: D000595:Amino Acid Sequence; D019086:Bridged Bicyclo Compounds, Heterocyclic / Q000378:metabolism; D005656:Fungal Proteins / Q000235:genetics / Q000378:metabolism*; D005978:Glutathione / Q000378:metabolism; D008969:Molecular Sequence Data; D010843:Pichia / Q000235:genetics / Q000378:metabolism*; D012441:Saccharomyces cerevisiae / Q000235:genetics / Q000378:metabolism*; D016415:Sequence Alignment; D015262:Xenobiotics / Q000378:metabolism*; D005723:gamma-Glutamyltransferase / Q000235:genetics / Q000378:metabolism*
chemical_list: D019086:Bridged Bicyclo Compounds, Heterocyclic; D005656:Fungal Proteins; D015262:Xenobiotics; C021149:bimanes; D005723:gamma-Glutamyltransferase; D005978:Glutathione