Purification and Characterization of Sweet Potato Peroxidase

The experiment purified and characterized the sweet potato peroxidase from sweet potato peel of Ipomoea batatas.The extraction and purification procedure included homogenate,water extraction,aqueous two-phase extraction,Sepharose CL-6B gel filtration,Phenyl Sepharose 6 fast flow hydrophobic chromatography and Con A Sepharose 4B affinity chromatography.The specific activity of purified peroxidase was 6 930 U/mg.The molecular weigh of sweet potato peroxidase was estimated to be 34 000 by SDS-PAGE as a single band,and its RZ value was about 2.0.The optimum activity and optimum temperature for enzyme reactron was at pH 5.5 and 70 ℃ respectively.The enzyme was stable in pH 2.2～10.At 60 ℃,it took 1 h to inactivate 60% of the enzyme.The results show that sweet potato peroxidase is very stable at high temperature and extreme pH.