Activity of the anion exchange protein (band 3) of human erythrocytes as affected by hydroxychloroaromatic chemicals.

The membranous segment of the anion transport protein (band 3) of the human erythrocyte membrane has been shown [T.L. Miller and R.J. Smith, Archs Biochem. Biophys. 250, 128 (1986)] to be destabilized by relatively low concentrations of many hydroxychloroaromatic compounds (HO-Cl chi-Ar), including hydroxychlorodiphenyl ethers (HO-Cl chi-DPE), major contaminants of technical grade pentachlorophenol (PCP). In the present study, HO-Cl chi-DPE also caused a concentration-dependent inhibition of the rate of sulfate exchange mediated by band 3 in human erythrocytes. The most active compound studied, 2-HO-Cl9-DPE, was about nine times more potent in inhibiting sulfate exchange than 2-HO-2',4,4'-Cl3-DPE, the least active compound studied. The potency of HO-Cl chi-DPE as inhibitors of anion exchange generally increased with the degree of chlorination. The concentration-dependent decreases in the sulfate exchange rate elicited by 2-HO-Cl9-DPE and 2-HO-2',4,4'-Cl3-DPE paralleled the effects of these compounds on the stability of band 3.