Characterization of superoxide dismutase from south Indian scorpion venom

A manganese containing superoxide dismutase was purified to homogeneity from the venom of scorpion Heterometrus fulvipes by ammonium sulfate fractionation followed by gel filtration on Sephadex G-100 and ion exchange chromatography on DEAE-cellulose. The enzyme has a molecular weight of 100,000. Optimum pH for enzyme activity was 8.5 and optimum temperature was 45 degrees C. The enzyme was not sensitive to either cyanide or hydrogen peroxide but was inhibited by chloroform-ethanol mixture and p-hydroxymercuribenzoate. Metal chelators, EDTA, o-phenanthroline and diethyldithiocarbamate inhibited the enzyme activity in decreasing order. The effect of 6 M urea, sodium dodecylsulfate, guanidinium chloride and nitroprusside on enzyme activity has been studied. An antiserum raised against H. fulvipes venom inhibited the superoxide dismutase activity.