title: Substrate-induced conformational change of human erythrocyte glucose transporter: inactivation by alkylating reagents.
abstract: The glucose transport carrier in human erythrocyte membranes, when transporting glucose, undergoes a conformation change. In an attempt to delineate the extent of this substrate-induced conformational change, transport inactivation by 7-chloro-4-nitrobenz-2-oxa-1,3-diazole, N-ethylmaleimide, iodoacetamide, and 2,4,6-trinitrobenzenesulfonic acid was examined in the presence and in the absence of D-glucose. All these alkylating agents inactivated the carrier. With each of these reagents, with the exception of trinitrobenzene-sulfonic acid, D-glucose modified the rate of inactivation as well as the activation enthalpy (delta H*) of the inactivation. The inactivation by trinitrobenzenesulfonic acid was not affected by the sugar. Based on these findings, it is suggested that the substrate-induced conformational change mostly occurs within the transmembrane hydrophobic domain while the hydrophilic extramembrane domains are largely outside of this change.
mesh_terms: D009327:4-Chloro-7-nitrobenzofurazan / Q000494:pharmacology; D000477:Alkylating Agents / Q000494:pharmacology*; D004910:Erythrocyte Membrane / Q000378:metabolism*; D005033:Ethylmaleimide / Q000494:pharmacology; D005947:Glucose / Q000378:metabolism*; D006801:Humans; D007460:Iodoacetamide / Q000494:pharmacology; D009004:Monosaccharide Transport Proteins / Q000378:metabolism*; D011487:Protein Conformation; D014302:Trinitrobenzenesulfonic Acid / Q000494:pharmacology
chemical_list: D000477:Alkylating Agents; D009004:Monosaccharide Transport Proteins; D014302:Trinitrobenzenesulfonic Acid; D009327:4-Chloro-7-nitrobenzofurazan; D005947:Glucose; D005033:Ethylmaleimide; D007460:Iodoacetamide