Interaction of zinc and other metal on the activity of erythrocyte delta-aminolevulinic acid dehydratase in vitro.

The interaction of zinc and other metal such as lead, mercury (II), cadmium, silver (II) on the activity of erythrocyte delta-aminolevulinic acid dehydratase (ALA-D) was investigated in vitro. At the concentrations ranging from 0.01 to 1.0 mmol/l, lead, mercury (II), cadmium and silver (II) strikingly inhibited the erythrocyte ALA-D activity. The in vitro addition of zinc having an activating effect for the erythrocyte ALA-D, was observed to eliminate the lead-induced inhibition of the erythrocyte ALA-D activity. And the degree of the elimination seemed to depend on the molar ratio (Zn/Pb) of both metal concentrations in the ALA-D assay. However, the inhibition of erythrocyte ALA-D activity caused by mercury (II), cadmium and silver (II) was not removed by the in vitro addition of zinc.