title: ONOOH does not react with H2: Potential beneficial effects of H2 as an antioxidant by selective reaction with hydroxyl radicals and peroxynitrite.
abstract: H2 has been suggested to act as an antioxidant when administered just before the reperfusion phase of induced oxidative stress. These effects have been reported, for example, for the heart, brain, and liver. It is hypothesized that this beneficial effect may be due to selective scavenging of HO(⋅) and ONOOH by H2. The reaction of H2 with HO(⋅) has been studied by pulse radiolysis in the past and is too slow to be physiologically relevant, not to mention that the reaction yields the reactive H(⋅) radical. We therefore investigated whether H2 reacts with ONOOH and whether the presence of H2 influences the yield of nitration of tyrosine by ONOOH. With only negative results, we entertained the notion that H2 may possibly exert its beneficial effects by reducing Fe(III) centers, oxidized during oxidative stress. However, neither hemes nor iron-sulfur clusters were reduced.
authors.affiliation: Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, CH-8093 Zurich, Switzerland; Department of Chemistry and Chemical Engineering, Eindhoven University of Technology, 5612 AZ Eindhoven, The Netherlands.
authors.forename: Jelle
authors.initials: J
authors.lastname: Penders
authors.affiliation: Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, CH-8093 Zurich, Switzerland.
authors.forename: Reinhard
authors.initials: R
authors.lastname: Kissner
authors.affiliation: Institute of Inorganic Chemistry, Department of Chemistry and Applied Biosciences, Swiss Federal Institute of Technology, CH-8093 Zurich, Switzerland. Electronic address: koppenol@inorg.chem.ethz.ch.
authors.forename: Willem H
authors.initials: WH
authors.lastname: Koppenol
mesh_terms: D000975:Antioxidants / Q000737:chemistry*; D006859:Hydrogen / Q000737:chemistry*; D017665:Hydroxyl Radical / Q000737:chemistry*; D010084:Oxidation-Reduction; D018384:Oxidative Stress; D030421:Peroxynitrous Acid / Q000737:chemistry*; D014443:Tyrosine / Q000737:chemistry
chemical_list: D000975:Antioxidants; D030421:Peroxynitrous Acid; D017665:Hydroxyl Radical; D014443:Tyrosine; D006859:Hydrogen
keywords: Free radicals; Hydrogen; Peroxynitrite; Scavenger; Stopped-flow kinetics; Thermodynamics