KAHLENBEWC, A., and DQLANSKY, D. Structural requirements of glucose for its binding to isolated human erythrocyte membranes. Can. J. Bischem.The inhibition by various derivatives of D-glucose of the stereospecific uptake of this sugar by isolated human erythrocyte membranes was determined. Single changes at each of the five hydroxyi groups of D-glucose, except for the 2-deoxy and 6-deoxy derivatives, resulted in a variable decrease in the binding afinity of the sugar which was dependent upon the nature and locus of the alteration. In addition, the presence of the pyranose ring oxygen is required for optimal binding. The largest decrease in afinity effected by a single change of any s f the three hydroxyl groups of D-glucose which participate in the binding reaction (i.e. those at carbons 1,3. and 4) was obtained by the removal or derivatization of the anomeric (C-l) hydroxyl. A similar decrease in binding afinity was obtained upon sulfur substitution of the ring oxygen. The results are interpreted as indicating that the binding of D-glucose to its erythrocyte membrane acceptor site is probably mediated by hydrogen bonds between this membrane component and the hydroxyl groups at carbons 1, 3, and 4 of D-gliucose and the pyranose ring oxygen.

A sensitive method for the measurement of the stereospecific uptake of D-glUCOSe by isolated human erythrocyte membranes has been developed. The method is based on the difference in uptake of L-[' C]glucose and D-[ *H]glucose

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