Abstract: A CuZn-SOD from Ficus carica leaves was separated and purified with ammonium sulfate fractionation, DEAE-Sepharose fast flow chromatography and Sephacryl S-100 HR chromatography techniques. One major bright band was achieved on polyacrylamide gel electrophoresis stained with nitroblue tetrazolium(NBT). The molecular weight of the enzyme subunit was determined by SDS-PAGE to be about 17800. We investigated the physical and chemical properties of the enzyme, and characterized its kinetic properties, such as the optimal pH, optimal temperature and the effect of chemical reagents and metal ions on the SOD. The results show that the stability of this purified SOD appeared to be better than other SODs reported. The analysis results of circular dichroism spectrum reveals that the enzyme possessed approximate 12.78% of α-helix in its secondary structure.

Key words: Ficus carica leaves, Superoxide dismutase, Separation and purification