Abstract
The milk-clotting protease from Bacillus mesentericus strain 76 is free of carbohydrate and lacks cysteine and cystine. The amino acid composition indicates a single peptide chain with 304 residues. Five amino acids - aspartic acid, threonine, serine, glycine and alanine - represent one-half of the total residues. The enzyme contains 35 aromatic amino acids and 103 ionic amino acids. The observed constant value of the ratio Menzyme:AZinc is 1:1 for active and acid denatured enzyme preparations, indicating that 0.1 M acetic acid causes denaturation of the enzyme but it can not eliminate the zinc ions.