Bacteriolytic enzyme induced from pyocinogenic Pseudomonas aeruginosa. Purification and characterization of...

A bacteriolytic enzyme, PR1-lysozyme, has been purified from the lysate of mitomycin C-induced pyocinogenic Pseudomonas aeruginosa, by acrinol treatment, Amberlite CG-50 chromatography, ammonium sulfate fractionation, Sephadex G-100 gel filtration and two cycles of SP-Sephadex C-50 chromatography. Homogeneity of the preparation was demonstrated by three electrophoretic techniques. PR1-lysozyme is a basic protein (pI, 9.4) and consists of a single polypeptide chain having a molecular weight of 24,000. The amino acid composition of the protein was analyzed, and no cystein residue was found among more than 210 amino acid residues. The optimum pH for enzymatic activity was 6.4 and the enzyme exhibited about 50 to 70 times greater specific activity than hen egg-white lysozyme when assayed with chloroform-killed P. aeruginosa as a substrate. By analyzing the products of enzymatic action on purified peptidoglycan of P. aeruginosa, the enzyme was identified as an N-acetylmuramidase, i.e., the same classification as hen-egg-white lysozyme. PR1-lysozyme did not show any activity towards intact cells of gram-positive and gram-negative bacteria tested. However, the enzyme was able to lyse chloroform-killed gram-negative and gram-positive bacteria.