Purification and characterization of a 43-kDa protease of Bacteroides gingivalis

From the culture supernatant of Bacteroides gingivalis ATCC 33277, a thiol protease was purified to homogeneity by fractional ammonium sulfate precipitation, ion-exchange chromatography, gel filtration, and isoelectric focusing. Its molecular weight was 43 kDa and showed similar enzymatic properties to a 300-kDa protease that was previously characterized.