Abstract
A protease was purified from Porphyromonas gingivalis 1101, a clinical isolate, by sequential sodium dodecyl sulfate-polyacrylamide gel electrophoresis, substrate diffusion gel electrophoresis, and electroelution. The enzyme cleaved radiolabeled human basement membrane type IV collagen and the synthetic collagen peptide substrate for eukaryotic collagenases. It was inactivated by the thiol protease inhibitor N-ethylmaleimide but not by EDTA or EGTA [ethylene glycol-bis(beta-aminoethyl ether)-N,N,N',N'-tetraacetic acid] and activated by reducing agents such as beta-mercaptoethanol. The enzyme exists as an active precursor protein of molecular mass 94 kDa and undergoes proteolytic cleavage to 75-, 56-, and 19-kDa forms. Biotin-labeled collagen bound specifically to the 94-kDa form of the protein and to its cleavage products in ligand blots, suggesting a role for this enzyme not only in collagen degradation but also in adhesion to collagenous substrata.