title: Catalase modifies yeast Saccharomyces cerevisiae response towards S-nitrosoglutathione-induced stress.
abstract: Nitric oxide is known to be a messenger in animals and plants. Catalase may regulate the concentration of intracellular *NO. In this study, yeast Saccharomyces cerevisiae cells were treated with 1-20 mM S-nitrosoglutathione (GSNO), a nitric oxide donor, which decreased yeast survival in a concentration-dependent manner. In the wild-type strain (YPH250), 20 mM GSNO reduced survival by 32%. The strain defective in peroxisomal catalase behaved like the wild-type strain, while a mutant defective in cytosolic catalase showed 10% lower survival. Surprisingly, survival of the double catalase mutant was significantly higher than that of the other strains used. Incubation of yeast with GSNO increased the activities of both superoxide dismutase (SOD) and catalase. Pre-incubation with cycloheximide prevented the activation of catalase, but not SOD. The concentrations of oxidized glutathione increased in the wild-type strain, as well as in the mutants defective in peroxisomal catalase and an acatalasaemic strain; it failed to do this in the mutant defective in cytosolic catalase. The activity of aconitase was reduced after GSNO treatment in all strains studied, except for the mutant defective in peroxisomal catalase. The content of protein carbonyls and activities of glutathione reductase and S-nitrosoglutathione reductase were unchanged following GSNO treatment. The increase in catalase activity due to incubation with GSNO was not found in a strain defective in Yap1p, a master regulator of yeast adaptive response to oxidative stress. The obtained data demonstrate that exposure of yeast cells to the *NO-donor S-nitrosoglutathione induced mild oxidative/nitrosative stress and Yap1p may co-ordinate the up-regulation of antioxidant enzymes under these conditions.
authors.affiliation: Department of Biochemistry, Vassyl Stefanyk Precarpathian National University, Ivano-Frankivsk, Ukraine. lushchak@pu.if.ua
authors.forename: Oleh V
authors.initials: OV
authors.lastname: Lushchak
authors.forename: Volodymyr I
authors.initials: VI
authors.lastname: Lushchak
mesh_terms: D002374:Catalase / Q000235:genetics / Q000378:metabolism*; D003600:Cytosol / Q000187:drug effects / Q000378:metabolism; D004789:Enzyme Activation / Q000187:drug effects; D005978:Glutathione / Q000378:metabolism; D005980:Glutathione Reductase / Q000378:metabolism; D009154:Mutation; D020030:Nitric Oxide Donors / Q000494:pharmacology; D018384:Oxidative Stress / Q000187:drug effects; D020675:Peroxisomes / Q000378:metabolism; D050050:Protein Carbonylation / Q000187:drug effects; D026422:S-Nitrosoglutathione / Q000494:pharmacology*; D012441:Saccharomyces cerevisiae / Q000187:drug effects* / Q000235:genetics / Q000378:metabolism; D029701:Saccharomyces cerevisiae Proteins / Q000235:genetics / Q000378:metabolism*; D013482:Superoxide Dismutase / Q000378:metabolism
chemical_list: D020030:Nitric Oxide Donors; D029701:Saccharomyces cerevisiae Proteins; D026422:S-Nitrosoglutathione; D002374:Catalase; D013482:Superoxide Dismutase; D005980:Glutathione Reductase; D005978:Glutathione