Effect of Mg2+ and Ca2+ on enzymatic elastolysis of insoluble elastin determined by a conductimetric method

The effect of some divalent cations on the elastolysis of insoluble elastin by pancreatic elastase has been studied with a conductimetric method. Mn2+ and Cu2+ give progressive inhibition, while Ca2+ initially slightly increases elastolysis, then becomes an inhibitor at concentrations higher than 10(-4) M. A stronger effect is demonstrated with Mg2+ which increases the initial velocity of the enzymatic reaction. However, there is no effect when N-succinyl-(Ala)(3)-paranitroanilide is used as the substrate. The different effects observed can be explained by an enzymatic activation process (cation-enzyme complex) and/or by a conformational change of the insoluble elastin.