Functional characterization of anion transport system isolated from human erythrocyte membranes.

The anion transport system of human red blood cells was isolated in vesicles containing the original lipids of the membrane and predominantly the 95,000-dalton polypeptides (Band 3) associated with intralipid particles. The vesicles display various characteristic properties of anion permeation closely resembling those of the native system. The properties include energy of activation, pH dependence, anion sleectivity, sensitivity to specific inhibitors, and exchange and net rates of sulfate transport. Based on these and other criteria, the functional properties of isolated vesicles could be equated with those of the intact cell system. Direct support for the involvement of 95,000-dalton polypeptides in permeation functions is provided.