The 105-kDa protein component of Bacillus cereus non-haemolytic enterotoxin (Nhe) is a metalloprotease with gelatinolytic and collagenolytic activity

A sequence of 91 amino acids residues, probably starting from the N-terminal of the mature protein, was determined for the 105-kDa protein of the non-haemolytic enterotoxin of Bacillus. The last part of this sequence was similar to parts of the N-terminal portions of two collagenases of Clostridium histolyticum and Clostridium perfringens. Zymography, with intact collagen Fibril and gelatin as substrates, showed that the 105-kDa protein had collagenolytic and gelatinolytic activity. The 105-kDa protein also showed activity against a typical collagenase substrate, azocoll, and was inhibited by EDTA and 1,10-phenanthroline. We conclude that the 105-kDa protein is a collagenase. (C) 1999 Federation of European Microbiological Societies.