Rampal A L, Jung C Y
Biochim Biophys Acta. 1987 Jan 26;896(2):287-94. doi: 10.1016/0005-2736(87)90189-1.
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.
人类红细胞膜中的葡萄糖转运载体在转运葡萄糖时会发生构象变化。为了描绘这种底物诱导的构象变化程度，研究了在有和没有D-葡萄糖存在的情况下，7-氯-4-硝基苯并-2-恶唑-1,3-二氮唑、N-乙基马来酰亚胺、碘乙酰胺和2,4,6-三硝基苯磺酸对转运的灭活作用。所有这些烷基化剂都会使载体失活。除三硝基苯磺酸外，每种试剂的D-葡萄糖都会改变失活速率以及失活的活化焓（ΔH*）。三硝基苯磺酸引起的失活不受糖的影响。基于这些发现，表明底物诱导的构象变化主要发生在跨膜疏水区域内，而亲水性膜外区域在很大程度上不在这种变化范围内。
