Binding of cytochalasin B to human erythrocyte glucose transporter.

Cytochalasin B, a potent inhibitor of D-glucose transport systems, binds to the glucose transporter purified from human erythrocytes as described previously [Kasahara, M., & Hinkle, P. C. (1977) J. Biol. Chem. 252, 7384]. The transporter binds 9.2 +/- 1.3 nmol of cytochalasin B/mg of protein with a dissociation constant of 0.18 microM. The binding is competitively inhibited by D-glucose (Ki = 43 mM). Phloretin, diethylstilbestrol, maltose, 6-O-propyl-D-galactose, propyl beta-D-glucopyranoside, and dithiothreitol were also linear competitive inhibitors of cytochalasin B binding. The propyl sugars have been shown to inhibit transport from either the plasma or cytoplasma side of the membrane, respectively. The binding of cytochalasin B to the isolated transporter was inhibited by both propyl sugars.