Zinc, copper and delta-aminolaevulinic acid dehydratase in vitro and in vivo.

The effects of zinc and copper on delta-aminolaevulinic acid dehydratase were studied in vitro and in vivo. The in vitro addition of zinc alone to whole blood resulted in a highly significant increase in enzyme activity. The addition of copper alone had the opposite effect with a significant decrease in enzyme activity. When both elements were added to whole blood the inhibitory effect of copper was reduced. In in vivo studies of plasma zinc, plasma copper and whole blood delta-aminolaevulinic acid dehydratase, a positive correlation was found between plasma zinc and whole blood delta-aminolaevulinic acid dehydratase and a negative correlation was found between plasma copper and enzyme activity.