GLUCOSE AFFINITY FOR THE GLUCOSE-TRANSPORTER GLUT1 IN NATIVE OR RECONSTITUTED LIPID BILAYERS - TEMPERATURE-DEPENDENCE STUDY BY BIOMEMBRANE AFFINITY-CHROMATOGRAPHY

The affinity of D-glucose and the transport inhibitor cytochalasin B ( CB) for the glucose transporter Glut1 was studied at 5-42 degrees C by quantitative frontal affinity chromatography on sterically immobilize d human red cell membrane vesicles, and on proteoliposomes containing reconstituted red cell membrane proteins. Glut1 in the vesicles showed the highest glucose affinity; the dissociation constant K-d(glc) was nearly constant (16+/-3 mM) from 15 degrees C to 37 degrees C. For Glu t1 in proteoliposomes K-d(glc) decreased from 56 mM at 5 degrees C to 26 mM at 42 degrees C. The CB-Glut1 affinity was strongest around 20 d egrees C and was mostly higher with the vesicles, K-d(CB) being 49 nM at 19 degrees C. The entropy and enthalpy changes for the interactions were calculated. (C) 1997 Elsevier Science B.V.