Purification and characterization of a novel serine protease compositain from compositae ( L.)

Abstract

In this research, a protease from the compositae ( L.) was extracted and purified through (NH4)(2)SO4 precipitation, CM-Sephadex and Sephacryl S200. At the end of purification by gel filtration on a Sephacryl S-200 column, 87.11-fold purification was achieved. It was shown that purified enzyme was homogeneous in terms of SDS-PAGE with molecular mass estimate of 30 kDa. The enzyme named compositain depicted an optimal pH of 8.0 and was stable at pH 7.0-9.0, and its optimal temperature was at 50 A degrees C. While Tween 80 (0.2 %) was activated to the purified protease enzyme, it was partially inhibited by 5 mM concentration of some metal salts and EDTA, PMSF, dithiothreitol, H2O2 and beta-mercaptoethanol. The enzyme activity was stable even in the presence of detergents and organic solvents. In addition, it was investigated whether the purified and characterized protease enzyme would cause to congeal milk. As a result, it was determined that the compositain could congeal milk and it would be used for cheese production. The compositain had potential application in food processing.