title: Inactivation of NADP(+)-dependent isocitrate dehydrogenase by reactive oxygen species.
abstract: Recently, we demonstrated that the control of cytosolic and mitochondrial redox balance and the cellular defense against oxidative damage is one of the primary functions of NADP(+)-dependent isocitrate dehydrogenase (ICDH) through supply of NADPH for antioxidant systems. When exposed to various reactive oxygen species such as hydrogen peroxide, singlet oxygen generated by photoactivated dye, superoxide anion, and hydroxyl radical produced by metal-catalyzed Fenton reactions, ICDH was susceptible to oxidative modification and damage, which was indicated by the loss of activity, fragmentation of the peptide as well as by the formation of carbonyl groups. Oxidative damage to ICDH was inhibited by antioxidant enzymes, free radical scavengers, and spin-trapping agents. The structural alterations of modified enzymes were indicated by the increase in thermal instability and binding of the hydrophobic probe 8-anilino-1-naphthalene sulfonic acid (ANSA). The reactive oxygen species-mediated damage to ICDH may result in the perturbation of cellular antioxidant defense mechanisms and subsequently lead to a pro-oxidant condition.
authors.affiliation: Department of Biochemistry, College of Natural Sciences, Kyungpook National University, Taegu 702-701, South Korea.
authors.forename: S M
authors.initials: SM
authors.lastname: Lee
authors.forename: T L
authors.initials: TL
authors.lastname: Huh
authors.forename: J W
authors.initials: JW
authors.lastname: Park
mesh_terms: D000817:Anilino Naphthalenesulfonates / Q000737:chemistry; D000818:Animals; D000975:Antioxidants / Q000494:pharmacology; D001386:Azides / Q000494:pharmacology; D002374:Catalase / Q000494:pharmacology; D004795:Enzyme Stability / Q000187:drug effects; D005456:Fluorescent Dyes / Q000737:chemistry; D016166:Free Radical Scavengers / Q000494:pharmacology; D006861:Hydrogen Peroxide / Q000494:pharmacology*; D017665:Hydroxyl Radical / Q000494:pharmacology*; D007521:Isocitrate Dehydrogenase / Q000037:antagonists & inhibitors* / Q000737:chemistry / Q000378:metabolism; D008353:Mannitol / Q000494:pharmacology; D010084:Oxidation-Reduction / Q000187:drug effects; D018384:Oxidative Stress / Q000187:drug effects; D011487:Protein Conformation / Q000187:drug effects; D017510:Protein Folding; D017382:Reactive Oxygen Species / Q000494:pharmacology; D026082:Singlet Oxygen / Q000494:pharmacology*; D013482:Superoxide Dismutase / Q000494:pharmacology; D013552:Swine; D013696:Temperature
chemical_list: D000817:Anilino Naphthalenesulfonates; D000975:Antioxidants; D001386:Azides; D005456:Fluorescent Dyes; D016166:Free Radical Scavengers; D017382:Reactive Oxygen Species; D026082:Singlet Oxygen; D017665:Hydroxyl Radical; D008353:Mannitol; C027132:1-anilino-8-naphthalenesulfonate; D006861:Hydrogen Peroxide; D007521:Isocitrate Dehydrogenase; C039355:isocitrate dehydrogenase (NADP+); D002374:Catalase; D013482:Superoxide Dismutase