13 Phage Lysozyme and Other Lytic Enzymes

Abstract

This chapter focuses on various phage lysozymes and other lytic enzymes. The T4 phage lysozyme is found mainly in the lysates, and only one lysozyme molecule for two phage particles has been recovered in a probably nonspecific manner, which is contrary to the case of T2 phage lysozyme. The lysozyme of the T4 phage is strongly basic and of a small size. Its enzymic specificity is found to be similar to egg white lysozyme and its specific activity towards the host cell (wall) is higher than that of egg white lysozyme. The amino acid sequence of T4 phage lysozyme suggests no apparent structural similarity between T4 phage lysozyme and egg white lysozyme. T4 phage lysozyme has been characterized as a lytic enzyme acting on the host cell wall from inside the cell. Besides the T series phages, lytic enzymes have been prepared from a virulent coli-phage N20F lysate. This enzyme is well characterized and is found to have two pH optima. The activity of phage lytic enzyme can be determined by various methods, which are mainly based on either turbidimetry or the estimation of solubilized components of the cell wall. The choice of method depends on the kind of research being done in the laboratory, and the amount of enzyme required for measurement. While laboratories of bacteriology or microbial genetics are always ready to use growing bacteria or plates for assay, laboratories of biochemistry usually prefer dry cell preparations.