Isolation, purification and characterization of superoxide dismutase from garlic

A simple and cost-effective way to purify superoxide dismutase (SOD) from garlic was proposed. The stepwise isolation and purification procedure consists of phosphate buffer and chloroform–ethanol extraction, acetone precipitation followed by ion exchange chromatography on DEAE column. The specific enzyme activity was 4124 U/mg protein with the recovery rate of 53.3% and concentration factor of 192, respectively. SDS-PAGE analysis showed high consistency of garlic SOD with cattle blood SOD. The enzyme activity of garlic SOD was greatly inhibited by cyanide and hydrogen peroxide while it could be well maintained at pH values ranging from 4 to 11. Only slight decrease of enzyme activity was identified at temperatures lower than 50 °C or by treatment with ultrasonic wave for 30 min. The ultraviolet absorbance of garlic SOD was found to be 269 nm.