Superoxide dismutase, SOD Activity Assay Kit | KB03011

Description

Superoxide dismutases (SODs) are metallo enzymes that catalyse the dismutation of the superoxide anion to molecular oxygen and hydrogen peroxide. Thus, it forms a crucial part of the cellular antioxidant defense mechanism. Bioquochem’s SOD Activity Assay Kit utilizes a tetrazolium salt for detection of superoxide radicals. Particularly, xantine oxidase and hypoxantine are the enzymes that generate these radicals (see scheme).

Excessive reactive oxygen species, especially superoxide anion (O₂•−), play important roles in the pathogenesis of many cardiovascular diseases, including hypertension and atherosclerosis. Superoxide dismutases (SODs) are the major antioxidant defense systems against O₂•−. There are three isoforms of SOD in mammals: the cytoplasmic Cu/ ZnSOD (SOD1), the mitochondrial MnSOD (SOD2), and the extracellular Cu/ZnSOD (SOD3). These enzymes require catalytic metal (Cu or Mn) for their activation.

SOD Activity Assay Kit

Bioquochem’s SOD Activity Assay Kit bases on the reduction of  WST-1, that produces a water-soluble coloured formazan dye. The rate of the reduction with a superoxide anion linearly relates to the xanthine oxidase (XO) activity. By contrast,  SOD inhibites this reaction. Therefore, the inhibition activity of SOD can be determined by a colorimetric method. Specifically, one unit of SOD corresponds to the amount of enzyme needed to exhibit 50% dismutation of the superoxide radical.

XO and SOD Antagonism in the Generation of Formazan Dye.

The conversion of xanthine and O₂ to uric acid and H₂O₂ by XOD generates superoxide radicals. As a result, the superoxide anions reduce a tetrazolium salt (WST-1) to a colored formazan product (WST-1 formazan) that absorbs light. SOD scavenges superoxide anions, thereby reducing the rate of formazan dye formation.