Identification and initial characterization of elastase activity associated with Vibrio cholerae

Strains of Vibrio cholerae O1 (Ogawa, Inaba) and non-Ol serogroups have bee n found to produce an elastolytic protease that can be detected on 0.3% ela stin agar plates or in broth cultures. The elastase enzyme appears to be ma ximally expressed in late log phase (14-18 h postinoculation) and has optim um activity at a pH range between 7 and 8. Comparative studies indicate tha t more than 60% of R cholerae strains analyzed quantitatively produce: more elastase in broth (two- to fourfold higher) than other elastase-positive V ibrio species such as Vibrio vulnificus. The V. cholerae elastase enzyme wa s not inhibited by trypsin, serine-protease, or thiol-protease inhibitors, but was inhibited by phosphoramidon. Ultrafiltration studies indicate the V . cholerae elastase enzyme has a molecular weight >30,000, and a 34K protei n with possible elastase activity has been detected by SDS-PAGE for one non -Ol isolate (strain 2396). Cumulative results suggest that the V. cholerae elastase is probably a member of the N-type metalloprotease family and shar es similar properties with other elastase enzymes described for pathogenic and nonpathogenic species in this genus.