Description_x000D_ General description_x000D_ Superoxide dismutases are a group of low molecular weight metalloproteins present in all aerobic cells of plants, animals and micro-organisms. They provide protection against damaging reactions with the superoxide radical anion (O2-) by catalyzing its disproportionation into oxygen and hydrogen peroxide._x000D_ Application_x000D_ Superoxide Dismutase from bovine liver has been used:_x000D_ • for measuring mitochondrial hydrogen peroxide production in skeletal muscle_x000D_ • as a positive control in Cu(II) binding stability assay_x000D_ • as a positive control in superoxide dismutase assay_x000D_ Superoxide dismutase from bovine liver has been used in a study to assess the inactivation of endothelial derived relaxing factor by oxidized lipoproteins. Superoxide dismutase from bovine liver has also been used in a study to investigate the role of hydrogen peroxide in the cytotoxicity of the xanthine/xanthine oxidase system._x000D_ Packaging_x000D_ 3000, 15000 units in glass bottle_x000D_ Biochem/physiol Actions_x000D_ Catalyzes the dismutation of superoxide radicals to hydrogen peroxide and molecular oxygen. Plays a critical role in the defense of cells against the toxic effects of oxygen radicals. Competes with nitric oxide (NO) for superoxide anion (which reacts with NO to form peroxynitrite), thereby SOD promotes the activity of NO. SOD has also been shown to suppress apoptosis in cultured rat ovarian follicles, neural cell lines, and transgenic mice._x000D_ Unit Definition_x000D_ One unit will inhibit reduction of cytochrome c by 50% in a coupled system with xanthine oxidase at pH 7.8 at 25 °C in a 3.0 mL reaction volume. Xanthine oxidase concentration should produce an initial ΔA550 of 0.025 ± 0.005 per min._x000D_ Physical form_x000D_ Suspension in 3.8 M (NH4)2SO4, pH 7.0_x000D_ Analysis Note_x000D_ For assay method, see McCord, J.M. and Fridovich,I., J. Biol. Chem., 244, 6049 (1969).