Purification of superoxide dismutase(SOD) from Spirulina platensis and its characterization

In this study, superoxide dismutase (SOD) was purified from Spirulinia platensis. For this purpose homogenization, ultracentrifugation and DEAE cellulose anion exchange chromatography steps were sequentially used. Activities and protein amounts for fractions were determined after each step. The SOD was purified 315-fold and 81% efficiency after DEAE cellulose anion exchange chromatography with respect to that of homogenate.Optimum temperature of SOD was determined as 5 ? C and Vmax and Km were found as 722 U/mg prot. and 0.23 mM xanthine, respectively. Storage stability of purified SOD was investigated in tris base buffer (pH 7.8, 50 mM), 30% glycerol and 50% (v/v) glycerol solutions at 5 ? C and room temperature. After 20 days, SOD in tris buffer solution lost almost all of its activity at room temperature, however, it protected about 50% of its initial activity at 5 ? C. On the other hand, in 30 and 50% (v/v) glycerol solutions it protected about 81% and 77 of its initial activity, respectively at 5 ? C. Thermal stability of SOD from Spirulina platensis was also investigated at 5, 40 and 50?C