Dual regulation of collagenase activity in bovine dental pulps

A monospecific rabbit anti-inhibitor serum did not cross-react with either intact latent collagenase or with the one pretreated by p-aminophenylmercuric acetate. Furthermore, immunoglobulin G purified from the antiserum quantitatively inhibited the anti-collagenolytic activity of the inhibitor in either the presence or absence of p-aminophenylmercuric acetate. But the immunoglobulin G did not affect latent collagenase at all. These facts, along with other lines of evidence, strongly support the possibility that the inhibitor may not be responsible for the latency of collagenase and allow us to propose a dual regulatory mechanism of collagenase activity; that is, an inactive form, per se, may thus be additionally kept in the inactive state by the existence of an inhibitor which is synthesized in the same pulp tissues.