Enzymes lytic against Pseudomonas aeruginosa produced by Bacillus subtilis YT-25. III. General properties of endo-N-acetylmuramidase of Bacillus subtilis YT-25.

The enzymatic behaviour, amino acid composition and some physical properties of a new endo-N-acetylmuramidase (B-enzyme) of Bacillus subtilis YT-25 were determined and compared with hen's egg white lysozyme. The molecular weight was estimated to be about 13000 by the sedimentation equilibrium method. The isoelectric point was pH 9.8. The amino acid composition indicates that the enzyme is rich in basic amino acids, especially lysin. Maximal activity on the lysis of cell walls of M. lysodeikticus occurred at pH 6.2. The enzyme was stable at pH 3.5_??_6.0. The specific activity for the lysis of cell walls of M. lysodeikticus was less than fourth part of that of hen's egg white lysozyme. Digest of cell walls of M. lysodeikticus with B-enzyme consisted greater numbers of high molecular products than digest with egg white lysozyme. Substrate specificity of B-enzyme seemed to be different from that of egg white lysozyme.