Immunological identification of the human erythrocyte monosaccharide transporter

Antibodies to the purified cytochalasin B binding component of the human erythrocyte glucose transporter were prepared in rabbits. They precipitated detergent-solubilized transporter, and partially inhibited its binding of cytochalasin B. The antibodies were used to locate the transporter polypeptide in SDS-polyacrylamide gels of erythrocyte membranes prepared from freshly drawn blood in the presence of protease inhibitors. They labelled only the region of the gel corresponding to that occupied by the purified transporter, with an apparent molecular weight range of 45,000–75,000. These findings indicate that the isolated transporter does not arise by proteolytic degradation of a larger polypeptide, either during the storage of blood or during purification of the transporter.