Autolytic Enzyme System of Clostridium botulinum

The mode of action of the autolytic enzymes of Clostridium botulinum type A strain 190L was investigated using a partially purified autolysin. The autolysin completely solubilized SDS‐treated cell walls of the organism, liberating 1.2 moles of NH2‐terminal‐L‐alanine and 0.6 moles of reducing groups per mole of glutamic acid. Neither the NH2‐termini of other amino acids nor COOH‐termini of any amino acids were released. These results show that the autolysin contains an N‐acetylmuramyl‐L‐alanine amidase and a hexosaminidase. A disaccharide and peptides were isolated from the wall lysate in a chromatographically homogeneous state. The reducing end of the disaccharide was elucidated to be N‐acetylglucosamine by borohydride reduction. This fact indicates that the hexosaminidase is likely to be an endo‐β‐N‐acetylglucosaminidase. A possible structure of the cell wall peptidoglycan is proposed.