Role of γ-glutamyltranspeptidase in detoxification of xenobiotics in the yeasts Hansenula polymorpha and Saccharomyces cerevisiae

Authors

  • Vira M. Ubiyvovk,

    1. Institute of Cell Biology, National Academy of Sciences of Ukraine, Drahomanov Street, 14/16, Lviv 79005 Ukraine
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  • Oleksandra V. Blazhenko,

    1. Institute of Cell Biology, National Academy of Sciences of Ukraine, Drahomanov Street, 14/16, Lviv 79005 Ukraine
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  • Daniel Gigot,

    1. Université Libre Bruxelles, Laboratory of Microbiology, Jean Wiame Institute, 1 Av E Gryson, B-1070 Brussels, Belgium
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  • Michel Penninckx,

    1. Université Libre Bruxelles, Laboratory of Microbial Physiology and Ecology, 642 rue Engeland, B-1180 Brussels, Belgium
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  • Andriy A. Sibirny

    Corresponding author
    1. Institute of Cell Biology, National Academy of Sciences of Ukraine, Drahomanov Street, 14/16, Lviv 79005 Ukraine
    2. Rzeszów University, Department of Metabolic Engineering, Cwiklinskiej 2, 35-310 Rzeszów, Poland
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Corresponding author. Institute of Cell Biology, National Academy of Sciences of Ukraine, Molecular Genetics and Biotechnology Department, Drahomanov Street, 14/16, Lviv 79005, Ukraine. Tel.: +380 322 740 363; fax: +380 322 721 648. sibirny@cellbiol.lviv.ua

Abstract

GGT1 gene of the methylotrophic yeast Hansenula polymorpha appears to be a structural and functional homologue of Saccharomyces cerevisiae CIS2/ECM38 gene encoding γ-glutamyltranspeptidase (γGT). This is confirmed by the absence of the corresponding activity of γGT in the mutant with disrupted GGT1 gene. It was shown that γGT 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 γGT-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.

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