Proteolytic activities of Suparen and Rennilase on buffalo, cow, and goat whole casein and β-casein

The proteolytic specificity and activity of Mucor miehei protease (Rennilase) and Endothia parasitica protease (Suparen) on buffalo, cow, and goat whole casein and beta-casein (CN) were studied by analyzing the degradation products. The results suggest that Rennilase hydrolyzes casein of the three species in a manner similar to that of chymosin, resulting in the formation of alpha(s1)-I and beta-I, -II, -III as initial degradation fragments of alpha(s1)- and beta-CN. alpha(s1)-I was also the initial breakdown product of alpha(s1)-CN by Suparen. Contrary to Rennilase, Suparen showed a higher affinity toward beta-CN and hydrolyzes beta-CN, giving rise to degradation products characterized by mobility lower than that of beta-CN. Increasing NaCl concentration (>3%) reduced the proteolysis of beta-CN of the three species by Rennilase but not by Suparen. The hydrolysis of alpha(s1)-CN and alpha(s1)-I by the two enzymes was enhanced in the presence of NaCl.