Modification of the erythrocyte anion carrier by chromate.

It was confirmed that chromate is taken up by human erythrocytes via the general anion carrier. The chromate flux is unidirectional and chromium is accumulated within red cells presumably due to intracellular reduction of Cr(VI) to Cr(III). The analysis of the initial rates of uptake of chromate revealed two distinct uptake mechanisms at low (0.001-0.01 mM) and at high (0.05-1.0 mM) chromate concentrations. After prolonged incubation with 1 mM chromate, the subsequent rate of uptake of chromate was decreased. It is suggested that the decreased uptake is due to a modification of the anion-transport protein by chromate.