Diffusional water permeability of human erythrocytes and their ghosts.
Diffusional water permeability of human erythrocytes and their ghosts.
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DOI：
10.1085/jgp.79.5.791
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发表时间：
1982-05
期刊：
影响因子：
--
通讯作者：
Brahm J
中科院分区：
文献类型：
--
作者：
Brahm J
用改进的连续流管法测量示踪剂外流速率，测定人红细胞和幽灵的扩散水渗透率，时间分辨率为2-3ms。在25℃时，红细胞和幽灵的渗透率分别为2.4x10(3)和2.9x10(3)cm S-1。通透性既不受pH值从5.5到9.5的变化，也不受渗透压高至3.3osol的影响。细胞外浓度为19 mM的锰离子没有改变扩散水的渗透性，正如最近的核磁共振测量所表明的那样。用对氯汞苯甲酸盐(PCMB)或对氯汞苯磺酸(PCMBS)1 mM进行抑制，可获得1×10(3)cm S-1的“地面”渗透率。抑制使红细胞和幽灵的透水率随温度升高，从21-30kJ·mol-1增加到60kJ·mol-1。尽管扩散水的渗透性比渗透渗透率低一个数量级，但PCMB和PCMBS的抑制、抑制前后的温度依赖性和渗透压的独立性表明，扩散水的渗透性具有与已报道的渗透渗透性相似的定性特征，这表明膜的相同性质决定了这两种类型的转运。推测PCMB(S)敏感的通透性高于地面通透性是通过完整的膜蛋白与其周围脂类之间的中间相发生的。
The diffusional water permeability of human red cells and ghosts was determined by measuring the rate of tracer efflux by means of an improved version of the continuous flow tube method, having a time resolution of 2-3 ms. At 25 degrees C, the permeability was 2.4 x 10(3) and 2.9 x 10(3) cm s-1 for red cells and ghosts, respectively. Permeability was affected by neither a change in pH from 5.5 to 9.5, nor by osmolality up to 3.3 osmol. Manganous ions at an extracellular concentration of 19 mM did not change diffusional water permeability, as recently suggested by NMR measurements. A "ground" permeability of 1 x 10(3) cm s-1 was obtained by inhibition with 1 mM of either p- chloromercuribenzoate (PCMB) or p-chloromercuribenzene sulfonate (PCMBS). Inhibition increased temperature dependence of water permeability for red cells and ghosts from 21 to 30 kJ mol-1 to 60 kJ mol-1. Although diffusional water permeability is about one order of magnitude lower than osmotic permeability, inhibition with PCMB and PCMBS, temperature dependence both before and after inhibition, and independence of osmolality showed that diffusional water permeability has qualitative features similar to those reported for osmotic permeability, which indicates that the same properties of the membrane determine both types of transport. It is suggested that the PCMB(S)- sensitive permeability above the ground permeability takes place through the intermediate phase between integral membrane proteins and their surrounding lipids.