THE KINETICS OF GLUCOSE-TRANSPORT IN HUMAN RED-BLOOD-CELLS
THE KINETICS OF GLUCOSE-TRANSPORT IN HUMAN RED-BLOOD-CELLS
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DOI：
10.1016/0005-2736(86)90342-1
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发表时间：
1986-05-28
期刊：
影响因子：
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通讯作者：
WALMSLEY, AR
中科院分区：
文献类型：
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作者：
LOWE, AG;WALMSLEY, AR
骤冷流装置和新开发的自动注射器系统已用于测量在 0°C 到 0°C 的温度下 D-[14C] 葡萄糖转运到人红细胞中的初始速率。至 53 度。 C. 发现在 0 度和 20 度下都令人满意地遵循 Haldane 关系。 C，但最大 D-[14C]葡萄糖转运速率的阿伦尼乌斯图在平衡交换和零反式流入的条件下是非线性的。通过非线性回归将数据拟合到葡萄糖转运的常规模型给出0°的值。 C 为 0.726.+-。 0.0498 s-1 和 12.1 .+-。控制卸载载体分子向外和向内运动的速率常数为 0.98 s-1，90.3 .+-。 3.47 s-1 和 1113 .+-。 494 s-1 用于载体-葡萄糖复合物的向外和向内运动。这四个速率常数的活化能分别为173±。 3.10, 127.+-. 4.78, 88.0.+-. 6.17 和 31.7.+-。 5.11 kJ .cntdot。 mol-1。这些参数表明，在低温下，运输机制的显着不对称性主要是由于向内的载体和载体-葡萄糖复合物的比例较高，并且在向内和向外的构象中载体对葡萄糖的亲和力之间存在相对较小的差异。在高温（生理）下，载体相当均匀地分布在向外和向内的构象之间，并且外部对葡萄糖的亲和力大约是内部的 2.5 倍。
A quenched-flow apparatus and a newly developed automated syringe system have been used to measure initial rates of D-[14C]glucose transport into human red blood cells at temperatures ranging from 0.degree. to 53.degree. C. The Haldane relationship is found to be obeyed satisfactorily at both 0 and 20.degree. C, but Arrhenius plots of maximum D-[14C]glucose transport rates are non-linear under conditions of both equilibrium exchange and zero trans influx. Fitting of the data by non-linear regression to the conventional model for glucose transport gives values at 0.degree. C of 0.726 .+-. 0.0498 s-1 and 12.1 .+-. 0.98 s-1 for the rate constants governing outward and inward movements of the unloaded carrier molecule and 90.3 .+-. 3.47 s-1 and 1113 .+-. 494 s-1 for outward and inward movements of the carrier-glucose complex. Activation energies for these four rate constants are respectively 173 .+-. 3.10, 127 .+-. 4.78, 88.0 .+-. 6.17 and 31.7 .+-. 5.11 kJ .cntdot. mol-1. These parameters indicate that at low temperatures the marked asymmetry of the transport mechanism raises mainly from the high proportion of inward-facing carriers and carrier-glucose complexes, and that there is a relatively small difference between the affinities of the carrier for glucose in the inward and outward-facing conformations. At high (physiological) temperature the carrier is fairly evenly distributed between outward- and inward-facing conformations and the affinity for glucose is about 2.5-times greater outside than inside.