Has collagenase activity. Active on soluble collagen, reconstituted type I collagen, heat denatured type I collagen and azocoll, but not gelatin or the synthetic bacterial collagenase substrate PZ-PLGPA. May play a role in virulence. Activity somewhat enhanced by calcium ions, inhibited by zinc and Fe(3+) ions and by p-chloromercuribenzoic acid and EDTA. Activity is enhanced by salivary peptide cystatin and reduced by salivary peptide histatin. Homodimer. Belongs to the peptidase U32 family. Upon comparison to genes from other strains this is probably a fragment, and may have a number of sequencing errors. Extended N-terminus.