Characterization of autolysins from Mycobacterium smegmatis.

This study demonstrates, for the first time, the autolytic enzymes associated with mycobacterial cell walls. Based on the release of radioactivity and ninhydrin-reactive material from isolated cell walls, it was shown that maximum activity occurs during the late log phase of growth and at a buffer pH of about 8.0. Chemical analyses of autolytic digests of isolated cell walls indicated that at least three autolysins are active under the conditions used. These are N-glycolylmuramic acid-L-alanine amidase, an aminopeptidase that releases L-alanine, and an endopeptidase that solubilizes and L-alanyl-D-glutamic acid dippetide. No other endopeptidase, carboxypeptidase, or glycosidase activity was detected.