A novel thermophilic lysozyme from bacteriophage phiIN93.

The lysozyme of bacteriophage phiIN93 was purified to apparent homogeneity with Carboxymethyl Sepharose and Hydroxyapatie columns from lysates of the phage grown on Thermus aquaticus TZ2. The enzyme is a single polypeptide chain with a molecular weight of 33,000. From the determined N-terminal amio acids of the enzyme, the locus of the gene was specified on a phiIN93 genome. The enzyme was not similar to egg white lysozyme, T4 phage lysozyme, or lambda phage lysozyme. The enzyme, phiIN93 lysozyme, was found to be a novel type of thermophilic lysozyme, which lyses specifically Thermus sp. cells, and exhibited conspicuous thermal stability at 95 degrees C for 1h in the presence of beta-mercaptoethanol.