The state of water in human and dog red cell membranes.
The state of water in human and dog red cell membranes.
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DOI：
10.1085/jgp.55.4.451
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发表时间：
1970-04
影响因子：
3.8
通讯作者：
Solomon, A K
中科院分区：
文献类型：
--
作者：
Vieira, F L;Sha'afi, R I;Solomon, A K
在7°~37℃温度范围内，狗和人红细胞膜的水扩散渗透系数的表观活化能分别为4.9±0.3千卡/摩尔和6.0±0.2千卡/摩尔，狗红细胞和人红细胞膜渗透系数的表观活化能分别为3.7±0.4千卡/摩尔和3.3±0.4千卡/摩尔。对狗和人来说，Lp和水的体积粘度η的乘积与温度无关，这表明红细胞膜的几何形状在我们实验的温度范围内都不是温度敏感的。狗红细胞膜的表观扩散活化能与水自扩散的表观活化能相同，为4.6-4.8千卡/摩尔，表明水在狗红细胞膜上的扩散过程与在自由溶液中的过程相同。人红细胞中水扩散的激活能稍高，但意义重大，这与这些细胞特有的较窄等效孔中的水-膜相互作用相一致。观察到渗透系数的表观活化能小于水在红细胞膜上扩散的表观活化能，这是粘性流动的特征，表明渗透压梯度下水在红细胞膜上的流动是一个粘性过程。
The apparent activation energy for the water diffusion permeability coefficient, Pd, across the red cell membrane has been found to be 4.9 ± 0.3 kcal/mole in the dog and 6.0 ± 0.2 kcal/mole in the human being over the temperature range, 7° to 37°C. The apparent activation energy for the hydraulic conductivity, Lp, in dog red cells has been found to be 3.7 ± 0.4 kcal/mole and in human red cells, 3.3 ± 0.4 kcal/mole over the same temperature range. The product of Lp and the bulk viscosity of water, η, was independent of temperature for both dog and man which indicates that the geometry of the red cell membrane is not temperature-sensitive over our experimental temperature range in either species. In the case of the dog, the apparent activation energy for diffusion is the same as that for self-diffusion of water, 4.6–4.8 kcal/mole, which indicates that the process of water diffusion across the dog red cell membrane is the same as that in free solution. The slightly, but significantly, higher activation energy for water diffusion in human red cells is consonant with water-membrane interaction in the narrower equivalent pores characteristic of these cells. The observation that the apparent activation energy for hydraulic conductivity is less than that for water diffusion across the red cell membrane is characteristic of viscous flow and suggests that the flow of water across the membranes of these red cells under an osmotic pressure gradient is a viscous process.