硒(Na_2SeO_3)稳定红细胞膜骨架蛋白的自旋标记ESR研究

THE STABILIZING EFFECT OF TRACE AMOUNT OF SELENIUM ON ERYTHROCYTE MEMBRANES

用自旋标记ESR方法研究了无机硒(Na_2SO_1)对红细胞膜的稳定作用.与对照组相比,加硒组膜的自旋标记ESR波谱弱和强固定化信号比值(W/S)下降,柔性(F)系数上升,这表明硒对膜收缩蛋白有保护作用.使用Triton X—100对膜作温和处理后的ESR波谱表明硒的作用位点是膜蛋白而非磷脂.使用SDS处理的标记膜的ESR波谱证明硒的保护作用并非由交联所致.因而,硒的作用是通过改变膜蛋白构象,促使收缩蛋白二聚体向四聚体或高聚体转变的方式稳定膜结构的.

The stabilizing effect of trace amount of selenium on erythrocyte membranes was studied by means of spin-labeing technique in this paper. The evidences showed that, compared with in selenium-free medium, the ratio of weak immobilizing components of the labeed erythrocyte membrane proteins to that of strong ones ( W/S) decreased and flexibility coefficient (F) increased by addition of selenium and incubation at 4℃ for a period of time, which suggested that the tetramers and oligomers of spectrins increased. The mild denaturing experiment by using Triton X-100 at 0℃ for one hour indicated that the selenium have inffunce on the proteins of erythrocyte membranes. The stabilization are neither due to electric interaction nor due to covanlently cross- linking. The configuration variation and subsequent transformation of dimers of spectrins to tetramers and oligomers is probably the main process leading to protection of the membrane skeletons from decomposition.