红细胞膜对NO_2^-通透性的研究

STUDY ON NO_2^- TRANSPORT ACROSS THE ERYTHROCYTE MEMBRANE

本文采用NO_2^-快速测量红细胞膜对阴离子的通透特性.NO_2^-跨膜运输进红细胞内后,和血红蛋白相互作用,使后者变为高铁血红蛋白,改变了红细胞内血红蛋白的吸收光谱,进而影响细胞悬浮液的光学特性.据此,测量加入NO_2^-后红细胞悬浮液在特定波长处光密度的时间变化,即能追踪阴离子跨膜运输的动态过程.红细胞膜阴离子运输专一性抑制剂DIDS能抑制约70%的NO_2^-跨膜运输.在15-38℃温度范围检测了NO_2^-跨膜通透速率的温度特性,给出活化能为60KJ·mol^(-1).

The anion transport property is the one of the most improtant functions of the erythrocyte. In this paper a new method is described for measuring the anion transport across the erythrocyte membrane. When No2- ions interacted with hemoglobin after penetrating into the erythrocyte the absorption spectrum of hemoglobin was changed, and hence the optical properties of cell suspension were affectedThe time course of change of OD value after adding NO2- to cdl suspension could be divided into three parts. First, NO2- ions transported across the erythrocyte membrane, most probably through the band 3 proteins. Second, NO2- ions diffused inside the cell in collision with hemoglobin molecules. Finally, the reaction of No2- with hemoglobin molecules also need some time.Within the experimental range of NO2- concentration, the first step was rate limitting process.According 'OD vs. time' curve the permeability time was given as a parameter for transport DIDS was a specific inhibitor of anion transport. It was deduced that the majority (70%) of the nitrite entering the erythrocyte was through DIDS - inhibitable pathway. The temperature dependent of the rate of transport NO2- was also measured Based on an Arrhenius plot within a range of 15 to 38℃ , the apperent activation energy was estimated to be 60 KJ·mol-1.The conclusion is that band 3 proteins are involved in transport NO2- across the erythrocyte membrane. The clinical purpose has also been discussed.