ACID AND SEMI-ALKALINE PROTEINASE IN SWISS-TYPE CHEESE

Two proteinase fractions (Emmental cheese: Em-I and II; Gruyere cheese : Gr-I and II) were eluted on CM-Sephadex at 0.6 M and 0.9-1.0 M NaCl. Em-I was most active in the acidic region near pH 3.8-4.0, and was st rongly inhibited by pepstatin. Products with the same mobilities as al pha(s1)-I casein and beta-1 casein appeared when Em-I acted on casein. However, kappa-casein was not completely decomposed faster than alpha (s1)-casein. Em-II was mainly inhibited by soy bean trypsin inhibitor and diisopropyl fluorophosphate, producing fragments with the same mob ility as gamma-casein. These properties of Em-I and II were similar to those of acid and alkaline proteinases in milk, respectively, and the y are, therefore, regarded as the acid and alkaline proteinases in mil k. Gr-I and II were eluted at the same concentration of NaCl as Em-I a nd II, respectively, on CM-Sephadex. The properties of Gr-I and II, su ch as optimum pH, inhibitory patterns and changes in PAGE of casein we re quite similar to those of Em-I and II, respectively. It was consequ ently concluded that Gr-I and II were the same enzymes as Em-I and II, respectively.