The effect of cholesterol incorporation on the temperature dependence of water permeation through liposomal membranes prepared from phosphatidylcholines.
The effect of cholesterol incorporation on the temperature dependence of water permeation through liposomal membranes prepared from phosphatidylcholines.
复制标题
胆固醇掺入对通过磷脂酰胆碱制备的脂质体膜的水渗透的温度依赖性的影响。
DOI：
10.1016/0005-2736(77)90026-8
复制
发表时间：
1977
期刊：
影响因子：
--
通讯作者：
J. de Gier
中科院分区：
文献类型：
--
作者：
M. Blok;L. van Deenen;J. de Gier
研究了水通过由磷脂酰胆碱和不同量的胆固醇组成的脂质体膜的渗透作为温度的函数。1.增加胆固醇的量引起的凝胶附近的水渗透率的突变逐渐消失的液晶相转变温度的二棕榈酰磷脂酰胆碱和二肉豆蔻酰磷脂酰胆碱脂质体。在胆固醇浓度高于约30摩尔%时，水渗透速率不再不连续。2.胆固醇的掺入在高于饱和卵磷脂的转变温度的水渗透活化能中产生急剧变化，所述转变温度在约15mol%胆固醇时发生。在转变温度以下，在0至33摩尔%胆固醇的区域中，水渗透的活化能逐渐降低。3.在含有不饱和磷脂酰胆碱的系统中，胆固醇也增强了水渗透的活化能，尽管程度较小。结果表明，脂肪酸链中顺式双键的位置在这方面是非常重要的。4.在胆固醇增加水渗透的温度依赖性的系统中，等渗甘油的温度依赖性也得到增强，并且膨胀也增加了相同数量的kcal/mol。
The permeation of water through liposomal membranes composed of phosphatidylcholine plus varying amounts of cholesterol was studied as a function of temperature. 1. Increasing amounts of cholesterol caused a gradual disappearance of the abrupt change in the rate of water permeation near the gel to liquid-crystalline phase transition temperature of dipalmitoylphosphatidylcholine and dimyristoylphosphatidylcholine liposomes. At cholesterol concentrations above about 30 mol% there was no longer a discontinuity in the rate of water permeation. 2. The incorporation of cholesterol produces a steep change in the activation energy of the water permeation above the transition temperature of the saturated lecithin occurring at about 15 mol% of cholesterol. Below the transition temperature there was a gradual decrease in the activation energy of the water permeation in the region of 0 to 33 mol% of cholesterol. 3. In systems containing unsaturated phosphatidylcholines cholesterol also enhanced the activation energy of the water permeation although to a lesser extent. The results indicate that the position of the cis-double bond in the fatty acid chain is very important in this respect. 4. In systems in which cholesterol increased the temperature dependence of the water permeation there is also an enhancement of the temperature dependence of the isotonic glycerol and erythritol swelling by the same number of kcal/mol.