Bacteriolytic enzymes from Staphylococcus aureus. Properties of the endo-beta-N-acetylglucosaminidase

An extracellular bacteriolytic endo-beta-N-acetylglucosaminidase has been purified and its specificity of action has been investigated (Wadström & Hisatsune, 1970a,b). Some enzymic properties, such as optimum pH for enzyme activity on whole cells and cell walls of Micrococcus lysodeikticus and Staphylococcus aureus and optimum pH for stability, have been studied. The activity was maximum in 0.05m-tris-hydrochloric acid buffer, pH7.0. A higher ionic strength inhibited cell-wall hydrolysis. Since the crude and purified enzymes were found to be unstable on storage, the stabilizing and inhibiting effects of several compounds were investigated. Several heavy metal ions inactivated the enzyme at very low concentrations. Thiol compounds stabilized and thiol-reacting compounds partly inhibited the activity. Crude and purified glucosaminidase was found to be heat-stable at acidic pH and unstable at alkaline pH as previously found for several lysozymes (endo-beta-N-acetylmuramidases). Other properties of the staphylococcal enzyme and hen's-egg-white lysozyme have been compared, since the modes of action of the two are quite similar (Wadström & Hisatsune, 1970b).