Purification and characterization of a protease produced by Vibrio cholerae non-O1 and comparison with a protease of V. cholerae O1

A protease produced by a clinical isolate of Vibrio cholerae non-O1 was purified to apparent homogeneity by ammonium sulfate fractionation and successive column chromatography on DEAE-Sephadex A25, Sephadex G100, Mono Q, and Phenyl Superose. Like the hemagglutinin-protease of V. cholerae O1, the purified protease had both hemagglutinating and proteolytic activities. The protease was heat labile, and in contrast to crude preparations, no Arrhenius effect was observed with the purified protein. Immunological analyses indicated that the proteases (or hemagglutinins) derived from V. cholerae O1 and non-O1 are identical.