溶血磷脂和二酰基磷脂的水吸附等温线及水化力
Water adsorption isotherms and hydration forces for lysolipids and diacyl phospholipids.
作者信息
Marsh D
机构信息
Max-Planck-Institut, für biophysikalische Chemie, Göttingen, Federal Republic of Germany.
出版信息
Biophys J. 1989 Jun;55(6):1093-100. doi: 10.1016/S0006-3495(89)82906-6.
The repulsive forces in a wide range of diacyl and monoacyl phospholipid systems have been obtained from the adsorption isotherms for water. From the exponential dependence of the repulsive pressure on the water content, information has been deduced regarding the hydration force. For diacyl phosphatidylcholines the strength of the hydration force and its characteristic decay length are in good agreement with values previously obtained by x-ray diffraction methods. For natural and synthetic diacyl phosphatidylcholines in the fluid lamellar phase, the hydration force extrapolated to zero layer separation (Po) is in the range 4-5.10(8) N.m-2 and the decay length is approximately 0.3 nm. The results for dimyristoyl, dipalmitoyl, and distearoyl phosphatidylcholines in the gel phase are very similar with Po approximately 2.5.10(8) N.m-2 and decay length of approximately 0.2 nm. Egg monomethyl phosphatidylethanolamine is less strongly hydrated: Po = 2.3.10(9) N.m-2, with a decay length of 0.3 nm. Egg phosphatidylethanolamine and bovine phosphatidylserine hydrate even more weakly with Po approximately 1.3.10(8) N.m-2 and decay length of approximately 0.15 nm. Mixtures with cholesterol or phosphatidylcholine increase both Po and the decay length for phosphatidylethanolamine to values closer to those for phosphatidylcholine. The repulsive forces deduced for egg lysophosphatidylcholine at 40 degrees C display a biphasic water dependence, with the low water phase being similar to lamellar egg phosphatidylcholine, and the phase at higher water content having a smaller value of Po = 2.10(8) N.m-2 but a longer decay length of approximately 0.45 nm, corresponding to a nonlamellar configuration. Bovine lysophosphatidylserine similarly yields values of PO = 1.2.108 N.m-2 and an effective decay length of 0.64 nm. The hydration behavior of the various diacyl phospholipids has been interpreted in terms of the mean-field molecular force theory of lipid hydration, and values deduced for the surface hydration potential of the various lipids. This analysis extends previous results on hydration forces, particularly to lysolipids and nonlamellar phases.
在广泛的二酰基和单酰基磷脂体系中，水的吸附等温线给出了排斥力。从排斥压力对含水量的指数依赖关系中，已经推导出有关水化力的信息。对于二酰基磷脂酰胆碱，水化力的强度及其特征衰减长度与先前通过X射线衍射方法获得的值高度一致。对于处于流体片层相的天然和合成二酰基磷脂酰胆碱，外推到零层间距（Po）时的水化力在4 - 5×10⁸ N·m⁻²范围内且衰减长度约为0.3 nm。凝胶相中二月桂酰、二棕榈酰和二硬脂酰磷脂酰胆碱的结果非常相似，Po约为2.5×10⁸ N·m⁻²且衰减长度约为0.2 nm。鸡蛋单甲基磷脂酰乙醇胺的水化程度较弱：Po = 2.3×10⁹ N·m⁻²，衰减长度为0.3 nm。鸡蛋磷脂酰乙醇胺和牛磷脂酰丝氨酸的水化程度更弱，Po约为1.3×10⁸ N·m⁻²且衰减长度约为0.15 nm。与胆固醇或磷脂酰胆碱的混合物会使磷脂酰乙醇胺的Po和衰减长度都增加，使其值更接近磷脂酰胆碱的值。在40℃下推导得到的鸡蛋溶血磷脂酰胆碱的排斥力呈现出双相水依赖性，低水相类似于层状鸡蛋磷脂酰胆碱，而高含水量相的Po值较小，为2×10⁸ N·m⁻²，但衰减长度较长，约为0.45 nm，对应于非层状结构。牛溶血磷脂酰丝氨酸同样给出Po = 1.2×10⁸ N·m⁻²的值和0.64 nm的有效衰减长度。各种二酰基磷脂的水化行为已根据脂质水化的平均场分子力理论进行了解释，并推导得到了各种脂质的表面水化电位值。该分析扩展了先前关于水化力的结果，特别是针对溶血脂质和非层状相。
Zotero 插件