The collagenase activity of Porphyromonas gingivalis is due to Arg-gingipain

Degradation of type I collagen by Porphyromonas gingivalis was monitored by fluorogenic, sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and growth assays. All three assays showed that inactivation of both the rgpA and rgpB genes was necessary to completely eliminate the capacity of P. gingivalis to cleave type I collagen. Leupeptin, an Arg-gingipain-specific protease inhibitor, almost completely inhibited collagen degradation by P. gingivalis cells whereas cathepsin B inhibitor II, a Lys-gingipain inhibitor, did not. A purified preparation of Arg-gingipains A and B hydrolyzed gelatin but did not cleave type I collagen, suggesting that the enzymes must be attached to the cell surface to exert collagenase activity. A number of substances used as adjuncts in periodontal therapy were also tested for their capacity to inhibit collagenase activity of P. gingivalis. Tetracycline, doxycycline, and chlorhexidine strongly inhibited collagenase activity.