INFLUENCE OF TEMPERATURE AND PH ON PROTEOLYTIC ACTIVITY OF RENNET EXTRACT

The influence of incubation temperature and pH on the proteolytic activity of rennet extract and crystalline rennin was investigated. The major results revealed that changes in the electrophoretic pattern of casein gave a much better evaluation of the proteolytic activity of rennin than did changes in nonprotein nitrogen. With casein as substrate and using changes in electrophoretic patterns as the criterion, the pH optimum fro rennin proteolysis was about 5.8. Changes in nonprotein nitrogen indicated a much lower pH optimum. The proteolysis products were pH-dependent and similar results were obtained with both crystalline rennin and rennet extract. The nature of proteolysis products was not temperature-dependent but at low temperature β-casein was more susceptible to proteolysis than αs1-casein, whereas the reverse applied at higher temperature. © 1969, American Dairy Science Association. All rights reserved.