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Catalytic Scavenging of Plant Reactive Oxygen Species In Vivo by Anionic Cerium Oxide Nanoparticles
Published on: August 26, 2018
Catalytic scavenging of peroxynitrite by catalase
1Institute of Applied Radiation Chemistry, Faculty of Chemistry, Technical University of Lodz, Wroblewskiego 15, 93-590 Lodz, Poland. lgebicka@mitr.p.lodz.pl
Abstract:
Peroxynitrite (ONOO(-)/ONOOH), the product of the diffusion controlled reaction between nitric oxide (*NO) and superoxide anion (O(2)(-)*), is a strong oxidizing and nitrating agent. Several heme proteins react rapidly with peroxynitrite, some of them catalyze its decomposition. In this work we found, contrary to previous reports, that catalase, a ferriheme enzyme, catalytically scavenges peroxynitrite. The second-order reaction rate constants of peroxynitrite decay catalyzed by catalase increase with decreasing pH and are equal to (2.7+/-0.2) x 10(6), (1.7+/-0.1) x 10(6) and (0.8+/-0.1) x 10(6) M(-1) s(-1) at pH 6.1, 7.1 and 8.0, respectively. This dependence suggests that peroxynitrous acid, ONOOH, is the species that reacts with heme center of catalase. The possible reaction mechanisms of the decay of peroxynitrite catalyzed by catalase and physiological relevance of this reaction are discussed.
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