Bacillus cereus autolytic endoglucosaminidase active on cell wall peptidoglycan with N-unsubstituted glucosamine residues.

An autolytic glycosidase from a lysozyme-resistant strain of Bacillus cereus capable of cleaving the glycosidic linkages of N-unsubstituted glucosamine in the cell wall peptidoglycan was studied. This glycosidase activity, together with N-acetylmuramyl-L-alanine amidase activity, was found in an autolytic enzyme preparation obtained from the 20,000 x g precipitate fraction by means of autolysis followed by ammonium sulfate fractionation. The major saccharide fragments resulting from digestion of the untreated, non-N-acetylated, cell wall peptidoglycan of B. cereus with the autolytic enzyme preparation were identified as N-acetylmuramyl-glucosamine and its dimer. The peptidoglycan N-acetylated with acetic anhydride could also be digested with the same enzyme preparation, giving N-acetylmuramyl-N-acetylglucosamine and its dimer as the major saccharide fragments.