A modified spectrophotometric assay of superoxide dismutase.

A simple and rapid method for the assay of superoxide dismutase in biological samples is described. Present method takes advantage of the inhibition of NADH-dependent-nitroblue tetrazolium reduction by the dismutase. Inhibition of the chromogen formation by superoxide dismutase was linear with increase in enzyme concentrations. The chromogen extract in butanol was stable even up to 48 hr. Superoxide dismutase activity, as assayed by the modified method, was in good agreement with that obtained using other methods.