title: A simple assay of the superoxide generation rate with Tiron as an EPR-visible radical scavenger.
abstract: Tiron (1,2-dihydroxybenzene-3,5-disulfonate) is oxidized to an EPR-visible semiquinone by superoxide radicals produced by xanthine oxidase. The steady-state level of the Tiron radicals increases with an increased xanthine oxidase concentration. A calibration plot has been obtained relating the steady-state concentration of the Tiron semiquinone determined by EPR-spectroscopy to the rate of 0.2 production as measured by the superoxide dismutase-sensitive cytochrome c reduction. This approach allows for a simple and sensitive assay of 0.2 generation rate in biological systems in the range of ca.0.1-4.0 microM/min using Tiron as a spin trap. The rate of 0.2 generation by antimycin-inhibited ischemic rat heart mitochondria has been measured by this method.
mesh_terms: D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt / Q000378:metabolism; D000818:Animals; D001557:Benzenesulfonates / Q000378:metabolism; D002417:Cattle; D003327:Coronary Disease / Q000378:metabolism; D003574:Cytochrome c Group / Q000378:metabolism; D004578:Electron Spin Resonance Spectroscopy / Q000379:methods; D007700:Kinetics; D008892:Milk / Q000201:enzymology; D008929:Mitochondria, Heart / Q000378:metabolism*; D010084:Oxidation-Reduction; D051381:Rats; D013481:Superoxides; D014969:Xanthine Oxidase / Q000378:metabolism*
chemical_list: D001557:Benzenesulfonates; D003574:Cytochrome c Group; D013481:Superoxides; D014013:1,2-Dihydroxybenzene-3,5-Disulfonic Acid Disodium Salt; D014969:Xanthine Oxidase