title: Glutathione peroxidase induction protects Saccharomyces cerevisiae sod1deltasod2delta double mutants against oxidative damage.
abstract: Saccharomyces cerevisiae mutants deficient in superoxide dismutase genes (sod1delta, sod2delta and the double mutant) were subjected to H2O2 stress in the stationary phase. The highest sensitivity was observed in the sod2delta mutant, while the sod1deltasod2delta double mutant was not sensitive. Sod mutants had lower catalase activity (44%) than wild-type cells, independent of H2O2 stress. Untreated cells of sod1deltasod2delta double mutants showed increased glutathione peroxidase activity (126%), while sod1delta had lower activity (77%) than the wild type. Glutathione levels in sod1delta were increased (200-260%) after exposure to various H2O2 concentrations. In addition, the highest malondialdehyde levels could be observed without H2O2 treatment in sod1delta (167%) and sod2delta (225%) mutants. In contrast, the level of malondialdehyde in the sod1deltasod2delta double mutant was indistinguishable from that of the wild type. These results suggest that resistance to H2O2 by sod1deltasod2delta cells depends on the induction of glutathione peroxidase and is independent of catalase, and that glutathione is a primary antioxidant in the defense against H2O2 in stationary phase sod1delta mutants.
authors.affiliation: Laboratório de Estresse Oxidativo, Departamento de Biofísica, Universidade Federal do Rio Grande do Sul, Porto Alegre, RS, Brazil.
authors.forename: V
authors.initials: V
authors.lastname: Manfredini
authors.forename: R
authors.initials: R
authors.lastname: Roehrs
authors.forename: M C R
authors.initials: MC
authors.lastname: Peralba
authors.forename: J A P
authors.initials: JA
authors.lastname: Henriques
authors.forename: J
authors.initials: J
authors.lastname: Saffi
authors.forename: A L L P
authors.initials: AL
authors.lastname: Ramos
authors.forename: M S
authors.initials: MS
authors.lastname: Benfato
mesh_terms: D000975:Antioxidants / Q000378:metabolism*; D002374:Catalase / Q000378:metabolism; D004790:Enzyme Induction; D005979:Glutathione Peroxidase / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism / Q000633:toxicity; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D017382:Reactive Oxygen Species / Q000378:metabolism; D012441:Saccharomyces cerevisiae / Q000201:enzymology* / Q000235:genetics; D013482:Superoxide Dismutase / Q000235:genetics* / Q000378:metabolism; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2
chemical_list: D000975:Antioxidants; D002374:Catalase; D005979:Glutathione Peroxidase; D006861:Hydrogen Peroxide; D017382:Reactive Oxygen Species; D013482:Superoxide Dismutase; D000072105:Superoxide Dismutase-1; D000099156:Superoxide Dismutase 2