DIFFUSION OF UNIVALENT IONS ACROSS LAMELLAE OF SWOLLEN PHOSPHOLIPIDS
DIFFUSION OF UNIVALENT IONS ACROSS LAMELLAE OF SWOLLEN PHOSPHOLIPIDS
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DOI：
10.1016/s0022-2836(65)80093-6
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发表时间：
1965-01-01
影响因子：
5.6
通讯作者：
WATKINS, JC
中科院分区：
文献类型：
--
作者：
BANGHAM, AD;STANDISH, MM;WATKINS, JC
一价阳离子和阴离子从自发形成的卵磷脂液晶中扩散出来与这些离子穿过生物膜的扩散非常相似。如果液晶的单元结构被认为是双分子小叶的结构，那么这些小叶对阴离子的渗透性比对阳离子的渗透性高许多个数量级。阳离子的扩散速率是非常显着的控制在水/脂质界面的表面电荷的符号和大小。随着脂质结构上的负电荷减少[长划线]，阳离子的扩散速率降低，对于带正电荷的膜[长划线]，负电荷减少至零，阴离子的扩散速率保持非常高。Cl-和I-的交换扩散速率大于F-、NO[image]、SO[image]-和HPO[image]，但在佳能系列中未检测到显著差异。Li+、Na+、K+、Rb+和胆碱。这些膜对水的渗透性很强。由于阳离子的扩散速率低，磷脂液晶结构似乎“结合”或“捕获”阳离子。发现随着脂质膜表面电荷的增加，每[μ]摩尔脂质的阳离子量增加。有人认为，如果阳离子被隔离在双分子小叶之间的水室，如果水室的厚度是由脂质头基的表面电荷密度和水相的离子强度决定的。根据双层理论，阳离子的捕获量也会有所不同。
The diffusion of univalent cations and anions out of spontaneously formed liquid crystals of lecithin is remarkably similar to the diffusion of such ions across biological membranes. If the unit structure of the liquid crystal is accepted as being that of a bimolecular leaflet, then these leaflets have been shown to be many orders of magnitude more permeable to anions than to cations. The diffusion rate for cations is very significantly controlled by the sign and magnitude of the surface charge at the water/ lipid interface. There is a decrease of the diffusion rate for cations as the negative charge on the lipid structure decreases[long dash]which diminishes to zero for a positively charged membrane[long dash]the diffusion rate of anions remaining very high. The exchange diffusion rate of Cl- and I- was greater than that of F-, NO[image], SO[image]- and HPO[image] but no significant differences were detectable for the canon series. Li+, Na+, K+, Rb+ and choline. The membranes are very permeable to water. Because the diffusion rate of cations is low, the phospholipid liquid crystalline structures appear to "bind" or "capture" cations. It is found that as the surface charge of the lipid lamellae is increased, the amount of cation per [mu]mole of lipid increases. It is argued that if the cation is sequestered in aqueous compartments between the bimolecular leaflets, and If the thickness of the aqueous compartments is determined by the surface charge density of the lipid head groups and by the ionic strength of the aqueous phase In accordance with double-layer theory, the amount of cation trapped would also be expected to vary.