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 erythrocytes has been used in a study to assess a kinetic model of radiation-induced inactivation of superoxide dismutase in nitrous oxide-saturated solutions. Superoxide dismutase from bovine erythrocytes has also been used in a study to investigate the possible participation of superoxide anion in the intestinal tryptophan 2,3-dioxygenase reaction._x000D_ Packaging_x000D_ 15000 units in glass bottle_x000D_ 30000, 75000, 300000 units in poly 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_ Lyophilized powder, essentially salt-free