OXIDATIVE STRESS-RESPONSE IN YEAST - INDUCTION OF GLUCOSE-6-PHOSPHATE-DEHYDROGENASE BY LIPID HYDROPEROXIDE IN HANSENULA-MRAKII

Hansenula mrakii IFO 0895 induces glutathione peroxidase as an oxidati ve stress response. Activities of other antioxidant enzymes-superoxide dismutase, catalase and cytochrome c peroxidase-were assayed. The sup eroxide dismutase activity did not change when the cells were cultured in the presence of lipid hydroperoxide, whereas the catalase and cyto chrome c peroxidase activities decreased. The intracellular glutathion e content and the activities of enzymes involved in glutathione biosyn thesis were not changed by oxidative stress. Glucose-6-phosphate dehyd rogenase, which is involved in the glutathione recycling system, was i nduced by oxidative stress to supply NADPH which is consumed by glutat hione reductase coupling with the glutathione peroxidase reaction.