The effect of calcium chloride on the activity and inhibition of bacterial collagenase.

The enzymatic behavior and inhibition patterns of collagenase of Clostridium histolyticum in the presence of 0.5 M and 3.4 mM CaCl2 have been examined viscosimetrically. The more concentrated salt was found to enhance the rate of digestion of calfskin collagen when either measured viscosimetrically or colorimetrically by trinitrobenzenesulfonate. However, the rate of digestion of calfskin gelatin is unaffected by 0.5 M CaCl2 as determined colorimetrically. Calcium chloride also proved to have a marked effect on the inhibitory behavior of a series of imidazole compounds. Histidine (10mM) is about three-fold more effective as an inhibitor in 0.5 M CaCl2 than in 3.4 mM CaCl2, whereas a reverse effect is true for histamine, Imidazolylpropionate (10mM) was only weakly inhibitory (16%) in 0.5 M CaCl2 and not at all in 3.4 mM CaCl2. Inhibition by 10 mM imidazole was not detectable. These observations may be useful in the design of inhibitors for tissue collagenases which share a number of common characteristics with the bacterial enzyme.