Abstract: The chymosin purified from glutinous rice wine is the reason why glutinous rice wine could coagulate Chinese royal cheese, one of traditional Chinese dairy produce. The coagulating characteristics of purified chymosin in glutinous rice wine were investigated systematically. The optimum coagulating temperature of purified chymosin was 45 ℃. The optimum coagulating pH was 5.5. Both the clotting activity and the proteolysis activity were stable between 45～55 ℃, pH 3.0～7.0. Na+, K+, Ca2+, Mg2+, Zn2+, Mn2+ and Fe2+ increased the clotting activity while Ca2+ showed the greatest effect. Cu2+ inhibited the clotting activity. The purified chymosin specifically hydrolyzed casein while having no effect on α-lactoalbumin and β-lactoglobulin. The main enzymatic cleavage site is N-terminal of M95. There are other enzymatic cleavage sites as well.

Key words: chymosin, enzyme properties, glutinous rice wine