Superoxide Dismutase from human erythrocytes

Analysis Note

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

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.³ SOD has also been shown to suppress apoptosis in cultured rat ovarian follicles, neural cell lines, and transgenic mice.^4,5

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. Superoxide dismutase erythrocytes in newborn children have higher activity than in adults. ⁶

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

Lyophilized powder containing potassium phosphate buffer salts

Application

Superoxide dismutase from human erythrocytes has been used in a study to identify in vitro glycated sites of human Cu-Zn-superoxide dismutase. ¹ Superoxide dismutase from human erythrocytes has also been used in a study to investigate a prospective test-system for the screening of cytoprotective drugs and their combinations. ²