Renal aminoacylase, a zinc enzyme

Renal aminoacylase is inactivated by dialysis against metal complexing agents such as o-phenanthroline. Activity can be restored by addition of zinc ions. A zinc dissociation constant of about 10(-10)M at pH 7.8 is obtained by titration of the enzyme with a metal ion buffer. The reactivity of the SH groups of the enzyme is considerably affected by zinc ions. The enzyme contains two essential zinc ions per molecule.