title: Zinc metalloenzyme properties of active and latent collagenase from rabbit bone.
abstract: 1. Inhibition of collagenase from rabbit bone cultures by the chelating agents 1,10-phenanthroline and EDTA is almost completely reversed by Zn2+; other metal cations are less effective in reversing the inhibition. Optimal restoration of activity is achieved at Zn2+ concentrations below that of the chelator, but excess of Zn2+ is inhibitory. 2. Prolonged incubation of collagenase with either chelator causes irreversible inactivation. This inactivation is prevented by Zn2+ at the same concentrations needed to reverse the primary inhibition. 3. Collagenase incorporates 65Zn by exchange when incubated with 1,10-phenanthroline and Zn2+ containing this radioactive isotope. The 65Zn2+ can be removed from its binding site in collagenase by 1,10-phenanthroline or EDTA. Irreversible inactivation of collagenase by chelators destroys its ability to incorporate 65Zn2+. 4. Latent collagenase, the inhibited form in which collagenase first appears in culture, behaves similarly to the active enzyme in 65Zn2+-exchange experiments, but is resistant to irreversible inactivation by chelators. 5. It is concluded that collagenase is a zinc metalloenzyme that forms an inactive and unstable apoenzyme on treatment with chelators. The bound inhibitor component of latent collagenase evidently stabilizes the apoenzyme.
mesh_terms: D000818:Animals; D001051:Apoenzymes / Q000378:metabolism; D001842:Bone and Bones / Q000201:enzymology*; D002118:Calcium / Q000494:pharmacology; D003035:Cobalt / Q000494:pharmacology; D004492:Edetic Acid / Q000494:pharmacology; D008667:Metalloproteins / Q000378:metabolism*; D003012:Microbial Collagenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D008956:Models, Chemical; D010618:Phenanthrolines / Q000494:pharmacology; D011817:Rabbits; D015032:Zinc / Q000378:metabolism*
chemical_list: D001051:Apoenzymes; D008667:Metalloproteins; D010618:Phenanthrolines; D003035:Cobalt; D004492:Edetic Acid; D003012:Microbial Collagenase; D015032:Zinc; D002118:Calcium