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.

Cooperative Binding of Ca2+ to Human Interstitial Collagenase Assessed by Circular Dichroism, Fluorescence, and Catalytic Activity

“…To determine if the effects of Ca 2ϩ on activity and fluorescence were reversible, we compared the catalytic activity of the recombinant enzyme with DnpS and collagen prior to Ca 2ϩ removal, after Ca 2ϩ removal with EGTA, and after reconstitution with Ca 2ϩ . Previous reports (11,12) indicate that prolonged incubation of collagenase with EDTA resulted in removal of zinc and irreversible denaturation of the protein. The data in Table I show that activity against both DnpS and collagen was completely lost on treatment with EGTA.…”

“…Calcium ions are also an essential components of the MMPs (11,12). Crystallographic analysis of the catalytic domain reveals three bound Ca 2ϩ in fibroblast collagenase (13,14) and two in the neutrophil enzyme (15).…”

Association between essential trace and toxic elements in scalp hair samples of smokers rheumatoid arthritis subjects

“…Zn supple-mentation was reported to decrease periarticular osteoporosis in rheumatoid arthritis patients (Honkanen et al, 1991). Defects in skeletal development have been reported in man due to zinc deficiency and also due to the acrodermatitis enteropathica, an inherited congenital disorder of zinc absorption (Alegre et al, 1984;Swann et al, 1981;Tudor et al, 2001). It has been reported that forearm bone mineral content is correlated with zinc intake in premenopausal women, suggesting a possible role for zinc in the maintenance of bone mass (Angus et al, 1988).…”

The relationship between the zinc nutritive status and biochemical markers of bone turnover in older European adults: the ZENITH study

“…Zinc has also been shown to be required by enzymes that have specific functions in bone metabolism (Cashman & Flynn, 1998). Both alkaline phosphatase (EC 3.1.3.1), which is required for bone calcification, and collagenase (EC 3.4.24.3), which is required for bone resorption and remodelling (Swann et al, 1981), are zinc metallo-enzymes.…”