Ni2+和Cd2+跨人红细胞膜的比较研究

以往对金属离子跨红细胞膜转运多集中在体内的宏量金属离子, 如Na+, K+, Ca2+, Mg2+及某些必需的重金属元素Fe2+, Cu2+, Zn2+等[1～3], 对其它重金属离子的跨膜转运研究较少. 我们曾研究了具有不同电荷的Co(Ⅲ)配合物的红细胞摄入动力学及机理[4]. 在此基础上进一步选择离子电荷数相同, 但电子组态不同的两个金属离子Ni2+和Cd2+为研究对象. Ni2+为d8组态, 动力学上是惰性的, 为体内必需的微量元素; 而Cd2+为d10组态, 动力学上是活性的, 却为有毒重金属, 本研究比较了它们跨人红细胞膜传递的动力学以及其与人红细胞作用的差异性.

Comparative Studies on the Transport Across Human Erythrocyte Membrane by Metal Ions Ni2+ and Cd2+ with Different Configurations of Electron

The rate constants of transmembrane transport of Ni 2+ and Cd 2+ with the same charge and different configurations of electron were determined in this experiment, and their first-order kinetic rate constant is as follows: for Ni 2+, k(Ni 2+)=0.002 0 h -1, and for Cd 2+, k(Cd 2+)=0.021 h -1. There are large differences between their rates of transmemebrane transport. The mechanisms of transmembrane transport of Ni 2+ and Cd 2+ are studied at the same time. The influences of the concentration of metal ions, pH of solution and the transport inhibitor on the uptake of Ni 2+ and Cd 2+ by human erythrocytes have been studied. The results show that Ni 2+ ions pass through the membrane by passive diffusion, while for Cd 2+, some of them are transported by the anion channel, the others by passive diffusion. Because there are different configurations of electron in the two ions, there are large difference in action of them with protein in the membrane of human erythrocytes.