Figure 3. SOD2 enzyme activity assay. SOD2 enzyme activity was determined by using a colorimetric based superoxide dismutase assay kit (Cell Technology). A and B show the summarized SOD2 activity for siRNA treatment and shRNA treatment, respectively. Preparations from scrambled RNA treated RCE cells reduced WST-1 formazan absorbance by 27%±4% (siControl) and 30%±6% (scrambled virus) relative to the blank, whereas preparations from siSOD2 and shSOD2 lentiviral treated RCE cells reduced absorbance by only 5%±3% and 9%±2%, respectively. WST-1 reduction in siRNA- or shRNA- treated cells was compared to that in siControl- or scrambled shRNA-treated cells, this ratio was calculated as the relative SOD2 activity.