Superoxide Dismutase from Escherichia coli

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. The direct electron transfer of superoxide dismutases can be efficiently promoted by a self-assembled monolayer of 3-mercaptopropionic acid confined on a gold electrode.

Superoxide dismutase from Escherichia coli has been used in a study to determine that anion binding properties of reduced and oxidized iron-containing superoxide dismutase reveal no requirement for tyrosine 34. Superoxide dismutase from Escherichia coli has also been used in a study to demonstrate that molecular dynamics simulation and limited proteolysis are complementary and specific tools to identify flexible sites in proteins.

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.

Contains Tris buffer salts

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

Manganese-containing enzyme

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.