Characterization of serine protease from mango (Mangifera indica cv. Chokanan) peel

Mango (Magnifera indica cv. Chokanan) is one of the most popular tropical fruits in the world and currently ranked 5 th in total world production among the major fruit crops. Mango peel is one of the major wastes of food and beverage industries, however, it can be used as a valuable, economic and available media sources for commercially producing the natural enzymes. This study aimed at characterizing serine protease which was previously purified from mango peel by alcohol salt aqueous two-phase system (ATPS). The molecular weight of purified protease was determined with sodium dodecyl polyacrylamide sulfate gel electrophoresis (SDS-PAGE) to be 65 kDa, it showed maximum activity (> 80%) at pH 4-10 and exhibited high thermal stability (>90%) for 60 min at 65°C with the highest activity at 70°C and at pH 8. Its activity was strongly inhibited by PMSF, but not by EDTA, pepstatin, or cysteine protease inhibitors. The activity of the protease was activated by Ca 2+ and Mg 2+ while Li + , Na + , K + and Sn 2+ had no effect on the protease activity. However, reduction in the activity of protease was observed in the presence of Ba 2+ , Zn 2+ , Pb 2+ , Co 2+ , Mn 2+