SUPEROXIDE DISMUTASE (C005B-348692)

General description

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.

Application

Superoxide Dismutase from bovine liver has been used:

• for measuring mitochondrial hydrogen peroxide production in skeletal muscle
• as a positive control in Cu(II) binding stability assay
• as a positive control in superoxide dismutase assay

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.

Biochem/physiol Actions

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.

Unit Definition

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.

Physical form

Suspension in 3.8 M (NH₄)₂SO₄, pH 7.0

Analysis Note

For assay method, see McCord, J.M. and Fridovich,I., J. Biol. Chem., 244, 6049 (1969).