Bicarbonate enhances peroxidase activity of Cu,Zn-superoxide dismutase. Role of carbonate anion radical and scavenging of carbonate anion radical by metalloporphyrin antioxidant enzyme mimetics. J Biol Chem 2002 Jan 11;277(2):1013-20
Date
10/30/2001Pubmed ID
11682485DOI
10.1074/jbc.M108585200Scopus ID
2-s2.0-0037059860 (requires institutional sign-in at Scopus site) 99 CitationsAbstract
Much evidence exists for the increased peroxidase activity of copper, zinc superoxide dismutase (SOD1) in oxidant-induced diseases. In this study, we measured the peroxidase activity of SOD1 by monitoring the oxidation of dichlorodihydrofluorescein (DCFH) to dichlorofluorescein (DCF). Bicarbonate dramatically enhanced DCFH oxidation to DCF in a SOD1/H(2)O(2)/DCFH system. Peroxidase activity could be measured at a lower H(2)O(2) concentration ( approximately 1 microm). We propose that DCFH oxidation to DCF is a sensitive index for measuring the peroxidase activity of SOD1 and familial amyotrophic lateral sclerosis SOD1 mutants and that the carbonate radical anion (CO(3)) is responsible for oxidation of DCFH to DCF in the SOD1/H(2)O(2)/bicarbonate system. Bicarbonate enhanced H(2)O(2)-dependent oxidation of DCFH to DCF by spinal cord extracts of transgenic mice expressing SOD1(G93A). The SOD1/H(2)O(2)/HCO(3)(-)-dependent oxidation was mimicked by photolysis of an inorganic cobalt carbonato complex that generates CO(3). Metalloporphyrin antioxidants that are usually considered as SOD1 mimetic or peroxynitrite dismutase effectively scavenged the CO(3) radical. Implications of this reaction as a plausible protective mechanism in inflammatory cellular damage induced by peroxynitrite are discussed.
Author List
Zhang H, Joseph J, Gurney M, Becker D, Kalyanaraman BAuthor
Balaraman Kalyanaraman PhD Professor in the Biophysics department at Medical College of WisconsinMESH terms used to index this publication - Major topics in bold
Amino Acids, AromaticAmyotrophic Lateral Sclerosis
Animals
Azulenes
Bicarbonates
Electron Spin Resonance Spectroscopy
Fluoresceins
Free Radical Scavengers
Hydrogen Peroxide
Metalloporphyrins
Mice
Mice, Transgenic
Molecular Structure
Neuroprotective Agents
Nitrogen Oxides
Oxidants
Oxidation-Reduction
Peroxidase
Sesquiterpenes
Spin Trapping
Spinal Cord
Superoxide Dismutase