Superoxide Dismutase Assay Kit

In the Superoxide Dismutase Assay, ions generated from the conversion of xanthine to uric acid, and hydrogen peroxide by xanthine oxidase (XOD), convert NBT to NBT-diformazan. NBT-diformazan absorbs light at 550 nm. SODs reduce superoxide ion concentrations and thereby lower the rate of NBT-diformazan formation. The extent of reduction in the appearance of NBT-diformazan is a measure of SOD activity present in experimental samples. The assay is free of interference by other catalytic activities, and is ideal for assaying SOD in mammalian cell lysates. The kit contains the proper lysis buffer and the reagents needed for 100 experimental tests, 50 positive controls, and 50 negative controls. Unlike some other assay kits for SOD, this system is not greatly disturbed by trace metals. Each assay requires only about five minutes, and after a simple calculation, the percent inhibition of the formation of NBT-diformazan by SOD is converted to the relative activity of the sample.