δ-Aminolevulinate dehydratase, a zinc dependent enzyme

Erythrocyte and liver tissue δ-aminolevulinate dehydratase activity was determined in rats fed a semipurified diet under controlled nutritional intake of zinc and copper. A significant decrease in enzymatic activity was observed in animals fed low zinc diet, while dietary copper had no effect. In vitro addition of zinc to the erythrocyte preparations obtained from rats on low zinc diet produced a slight increase in enzymatic activity. It appears that, even though zinc may be the metal ion activator of δ-aminolevulinate dehydratase, the requirement of this metal is at the site of synthesis of this enzyme.