For the determination of SOD activity the method of Beauchamp and Fridovich (1971) was followed. The principal was to measure the absorbance at 560nm which determined the photoreduction of nitroblue tetrazolium (NBT).
The reaction contained 650ul phosphate buffer and added with 100ul of methionine, then added 50ul of riboflavin along with 100 ul of enzyme extract. The reaction was added with NBT and shook well. Left it for 3 minutes and reaction was started by placing tubes below two 15 W fluorescent lamps for 10 minutes, took the absorbance on a spectrophotometer.