人类红细胞中己糖转运系统的不对称性。使用非转运性抑制剂的实验。

The asymmetrical nature of sugar affinity for the hexose transfer system in human red cells has been demonstrated using purified 4,6-O-ethylidene-alpha-D-glucopyranose (ethylidene glucose) to inhibit the exchange of glucose, 3-O-methyl glucose and galactose. 2. The half-saturation concentration for ethylidene glucose inside the cell is estimated at ca. 110 mM whereas on the outside the value for exchange inhibition is ca 11mM. 3. The asymmetrics of affinities of two related non-transportable inhibitors 1,2-O-isopropylidene-D-glucofuranose and methyl-2,3-di-O-methyl-alpha-D-glucopyranoside have also been studied. 4. From experiments at varying concentrations and on theoretical grounds the half-saturation concentration for non-transportable inhibitors on the outside surface is shown to be over-estimated by measuring inhibition of exchange. In consequence the actual asymmetry of affinities may be greater than observed. 5. Experiments with ethylidene glucose also suggest that conformational changes redistributing components of the hexose transfer system between inward and outward facing modes may occur.

利用纯化的4,6-O-亚乙基-α-D-吡喃葡萄糖（亚乙基葡萄糖）抑制葡萄糖、3-O-甲基葡萄糖和半乳糖的交换，已证明人类红细胞中己糖转运系统对糖亲和力的不对称性质。2. 细胞内亚乙基葡萄糖的半饱和浓度估计约为110 mM，而细胞外抑制交换的值约为11 mM。3. 还研究了两种相关的非转运抑制剂1,2-O-异丙叉基-D-呋喃葡萄糖和甲基-2,3-二-O-甲基-α-D-吡喃葡萄糖苷亲和力的不对称性。4. 通过不同浓度的实验并基于理论依据，通过测量交换抑制表明，细胞外表面非转运抑制剂的半饱和浓度被高估。因此，亲和力的实际不对称性可能比观察到的更大。5. 用亚乙基葡萄糖进行的实验还表明，可能发生构象变化，使己糖转运系统的组分在向内和向外模式之间重新分布。

Asymmetry of the hexose transfer system in human erythrocytes. Experiments with non-transportable inhibitors.