The temperature dependence of human erythrocyte transport of phosphate, phosphite and hypophosphite.
The temperature dependence of human erythrocyte transport of phosphate, phosphite and hypophosphite.
复制标题
人体红细胞运输磷酸盐、亚磷酸盐和次磷酸盐的温度依赖性。
DOI：
10.1016/0005-2736(90)90049-t
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发表时间：
1990
期刊：
影响因子：
--
通讯作者：
Labotka,RJ
中科院分区：
文献类型：
--
作者：
Galanter,WL;Labotka,RJ
红细胞阴离子转运蛋白（带3或AE 1）介导的流入的三个非球形基板，二价阴离子磷酸盐和亚磷酸盐，和单价次磷酸盐的温度依赖性进行了测定。发现在所有三种阴离子的流入的温度依赖性的相变。对于磷酸盐、亚磷酸盐和次磷酸盐，转变温度的95%置信限分别为：34.6-38.1° C、7.4-9.1° C和6.7-9.7° C，而转变时的临界流入速率分别为29-50、64-102和26-58离子/秒/载体。临界速率而不是转变温度具有类似的量级，表明转变与运输机制而不是热蛋白质构象变化有关。这些临界速率比Cl−和Br−的自交换所报道的速率低两个数量级（Brahm，J.（1977）J.Gen.Physiol.70，283-306）。一价次磷酸盐的临界速率类似于二价磷酸盐和亚磷酸盐的临界速率，但不类似于Cl−的临界速率，这表明这种效应是由底物的结构而不是其电荷介导的。在AE 1介导的球形和非球形阴离子的运输中发生相变的速率r c的差异表明两类阴离子和蛋白质之间的相互作用存在差异。
The temperature dependence of the erythrocyte anion transport protein (Band 3 or AE1) mediated influx of three nonspherical substrates, the divalent anions phosphate and phosphite, and the monovalent hypophosphite, were determined. Phase transitions were found in the temperature dependence of the influxes of all three anions. The 95% confidence limits for the transition temperatures were: 34.6–38.1° C, 7.4–9.1° C and 6.7–9.7° C for phosphate, phosphite and hypophosphite, respectively, while the critical influx rates at the transitions were 29–50, 64–102 and 26–58 ions/s per carrier, respectively. That the critical rates rather than the transition temperatures are of similar magnitude indicates that the transitions are related to transport mechanisms rather than to thermal protein conformational changes. These critical rates are two orders of magnitude lower than those reported for the self-exchange of Cl− and Br−(Brahm, J.(1977) J. Gen. Physiol. 70, 283–306). The critical rate of monovalent hypophosphite is similar to that of divalent phosphate and phosphite, but not to that of Cl− indicating that this effect is mediated by the structure of the substrate rather than by its charge. The disparity in the rates r c at which phase transitions occur in AE1-mediated transport of spherical and nonspherical anions indicates a difference in the interaction between the two classes of anions and the protein.