Superoxide dismutase (SOD) catalyzes the destruction of the O2- free radical, protecting oxygen-metabolizing cells against harmful effects of superoxide free-radicals. SOD protects hyaluronate against depolymerization by free-radicals and indicated that exogenous SOD might have an anti-inflammatory effect. The O2-ion, which has been considered important in aging, lipid peroxidation and the peroxidative hemolysis of red blood cells, is formed by the univalent reduction of O2 during various enzymatic reactions or by ionizing radiation. There is also superoxide radical formation during leukocyte phagocytosis. SOD deficiency might lead to Heinz body hemolytic anemia. Superoxide dismutase is widespread in nature, being present in all oxygen-metabolizing cells. It has been purified from diverse sources such as: fungi, green pea, Streptococcus mutans, wheat germ, E. coli, Saccharomyces cerevisiae and Neurospora crass. Three superoxide dismutases are characterized by different metal content. A blue-green Cu(II)-Zn(II) enzyme comes from human and bovine erythrocytes, a wine-red Mn(III) protein is found in E. coli, and in chicken, and rat liver mitochondria and a yellow Fe(III) enzyme from E. coli. The chicken liver cytosomal enzyme is the copper-zinc type. Bovine erythrocyte SOD, to which the following data apply, has been extensively studied. It is identical to the enzyme from human erythrocytes and from beef heart. CAS No: 9054-89-1 Molecular Weight: 32.5kD Source: Bovine erythrocytes Appearance: Pale blue lyophilized powder Activity: 2500 units per mg dry weight Unit Definition: 1 unit causes a 50% inhibition in the rate of reduction of Cytochrome C. Quality Control: SDS-PAGE Solubility: Readily soluble in 0.05M potassium phosphate, 0.1M EDTA, pH 7.8, at 5mg/ml. Spectrophotometric Date (E1%280): 2.46 Carbonic Anhydrase: 0.00091% Inhibitors: Cyanide inhibits cupro-zinc SOD but has no effect on the mangano enzyme of chicken liver mitochondria. SOD is inactivated by H2O2 and may be protected by catalase with which it is usually associated. In some tissue including cerebral cortex and thyroid, SOD is present but not catalase. Storage and Stability: Lyophilized and reconstituted products are stable for 6 months after receipt at -20C. Reconstitute with sterile 0.05M potassium phosphate, 0.1M EDTA, pH 7.8. Aliquot to avoid repeated freezing and thawing. Store at -20C. For maximum recovery of product, centrifuge the original vial after thawing and prior to removing the cap. Further dilutions can be made in assay buffer.
