Purification of milk-clotting protease from Bacillus mesentericus strain 76

A two-step procedure for the isolation of pure enzyme from Bacillus mesentericus strain 76 is developed. Ion-exchange chromatography on CM-Sephadex-C50 is used as a second step after precipitation from ethanol. The pure enzyme preparation, obtained after gel filtration on Sephadex-G25 of the ion-exchange chromatographically separated product, possess the highest specific activity achieved. The homogeneity of the final preparation is proved by determination of the N-terminal amino acid (Arg) and by SDS-PAGDE (single disc).