title: Inhibition of succinate-linked respiration and complex II activity by hydrogen peroxide.
abstract: Hydrogen peroxide produced from electron transport chain derived superoxide is a relatively mild oxidant, and as such, the majority of mitochondrial enzyme activities are impervious to physiological concentrations. Previous studies, however, have suggested that complex II (succinate dehydrogenase) is sensitive to H(2)O(2)-mediated inhibition. Nevertheless, the effects of H(2)O(2) on succinate-linked respiration and complex II activity have not been examined in intact mitochondria. Results presented indicate that H(2)O(2) inhibits succinate-linked state 3 mitochondrial respiration in a concentration dependent manner. H(2)O(2) has no effect on complex II activity during state 2 respiration, but inhibits activity during state 3. It was found that conditions which prevent oxaloacetate accumulation during state 3 respiration, such as inclusion of rotenone, glutamate, or ATP, blunted the effect of H(2)O(2) on succinate-linked respiration and complex II activity. It is concluded that H(2)O(2) inhibits succinate-linked respiration indirectly by sustaining and enhancing oxaloacetate-mediated inactivation of complex II.
authors.affiliation: Free Radical Biology and Aging Research Program, Oklahoma Medical Research Foundation, Oklahoma City, OK 73104, USA.
authors.forename: Michelle D
authors.initials: MD
authors.lastname: Moser
authors.forename: Satoshi
authors.initials: S
authors.lastname: Matsuzaki
authors.forename: Kenneth M
authors.initials: KM
authors.lastname: Humphries
mesh_terms: D000255:Adenosine Triphosphate / Q000494:pharmacology; D000818:Animals; D019069:Cell Respiration / Q000187:drug effects; D004789:Enzyme Activation / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D066298:In Vitro Techniques; D008928:Mitochondria / Q000187:drug effects / Q000378:metabolism; D009243:NAD / Q000378:metabolism; D009249:NADP / Q000378:metabolism; D051381:Rats; D017207:Rats, Sprague-Dawley; D013385:Succinate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D019802:Succinic Acid / Q000378:metabolism*
chemical_list: D004791:Enzyme Inhibitors; D009243:NAD; D009249:NADP; D000255:Adenosine Triphosphate; D019802:Succinic Acid; D006861:Hydrogen Peroxide; D013385:Succinate Dehydrogenase