Purification and Some Properties of Alkaline Protease from Penicillium Expansum

An alkaline protease was purified from culture broth Penicillium expansum by fractioning with acetone and column chromatography on Sephadex G-100 and DEAE-Sephadex A-50. The homogeneity of the final product was demonstrated on polyacrylamide gel electrophoresis in the presence of sodium dodecylsulphate which showed a single protein band. The purified enzyme had a molecular weight of about 20500 on polyacrylamide disc electrophoresis. The optimal pH and temperature for enzyme activity were found to be 10.5 and 35°C, respectively. The activity was found to be enhanced by addition of cysteine, mercaptoethanol and Co2+ whereas inhibition was observed in the presence of Hg2+ and Ag2+. Addition of Ca2+, Zn2+ and Mn2+ did not produce any significant effect on enzyme activity.