Hydrogen peroxide-induced carbonylation of key metabolic enzymes in Saccharomyces cerevisiae: the involvement of the oxidative stress response regulators Yap1 and Skn7

H2O2 induces a specific protein oxidation in yeast cells, and the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (Tdh) is a major target. Using a 2D-gel system to study protein carbonylation, it is shown in this work that both Tdh2p and Tdh3p isozymes were oxidized during exposure to H2O2. In addition, we identified two other proteins carbonylated and inactivated: Cu,Zn-superoxide dismutase and phosphoglycerate mutase. The oxidative inactivation of Cu,Zn-superoxide dismutase decreases the antioxidant capacity of yeast cells and probably contributes to H2O2-induced cell death. Cyclophilin 1 was also carbonylated, but CPH1 gene disruption did not affect peroxide stress sensitivity. The correlation between H2O2 sensitivity and the accumulation of oxidized proteins was evaluated by assaying protein carbonyls in mutants deficient in the stress response regulators Yap1p and Skn7p. The results show that the high sensitivity of yap1Δ and skn7Δ mutants to H2O2 was correlated with an increased induction of protein carbonylation. In wild-type cells, the acquisition of stress resistance by pre-exposure to a sublethal H2O2 stress was associated with a lower accumulation of oxidized proteins. However, pre-exposure of yap1Δ and skn7Δ cells to 0.4 mM H2O2 decreased protein carbonylation induced by 1.5 mM H2O2, indicating that the adaptive mechanism involved in the protection of proteins from carbonylation is Yap1p- and Skn7p-independent.