Purification of Bacteriophage T4 Lysozyme*

The lysozyme of bacteriophage T4 was purified to apparent homogeneity from lysates of the phage grown on Escherichia coli. The enzyme is a single polypeptide chain of molecular weight 19,000, with a single NH&erminal methionine residue and a single COOH-terminal leuciue residue. The amino acid composition of the protein was determined. The phage lysozyme exhibits a much greater specific activity when assayed with E. coli as a substrate than does egg white lysozyme. The enzyme was found to have muramidase activity, as egg white lysozyme does, when cell walls of Micrococcus lysodeikticus were used as substrate. The stability of the enzyme and the pH of optimum activity are described.