Purification and characterization of Cu, Zn-superoxide dismutase from black soybean

► The purified superoxide dismutase (SOD) is a double-strand protein with intra-molecular disulfide bridges. The isoelectric point was determined to be 5.6. ► The enzyme is a type of copper plus zinc superoxide dismutase (Cu, Zn-SOD). ► The purified SOD was thermostable up to 50 °C, and the activity could be well maintained between pH 6.0 and 8.0. ► The SOD exerted protective effect against oxidative stress of UVC radiation in normal human liver cell strain L-02 cells.