Activity Assays for Bacteriophage Endolysin PlyPy

Abstract

Bacterial viruses (bacteriophages) escape and kill their host by degrading the bacterial peptidoglycan layer through the mechanism of enzymes called endolysins: peptidoglycan degrading enzymes. The method included here is useful for the initial characterization of any endolysin, regardless of the specific catalytic domain (as long as the activity results in a reduction in the optical density), in order to determine its optimal enzymatic (lytic) activity. This protocol is specific for the Streptococcus pyogenes phage endolysin PlyPy, but can be adapted for any peptidoglycan degrading enzyme.