SURFACE DIPOLE-MOMENTS OF LIPIDS AT THE ARGON-WATER INTERFACE - SIMILARITIES AMONG GLYCEROL-ESTER-BASED LIPIDS
SURFACE DIPOLE-MOMENTS OF LIPIDS AT THE ARGON-WATER INTERFACE - SIMILARITIES AMONG GLYCEROL-ESTER-BASED LIPIDS
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DOI：
10.1016/s0006-3495(90)82365-1
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发表时间：
1990-07-01
影响因子：
3.4
通讯作者：
BROCKMAN, HL
中科院分区：
文献类型：
--
作者：
SMABY, JM;BROCKMAN, HL
测定了19类38种脂类在Ar-Buffer界面上的表面电位-表面压力-面积等温线。这些脂类都表现出有限范围的液体膨胀表面压力-面积行为。对于大多数物种，表面电势与倒易面积的线性关系很好，但获得了非零的截距。这表明脂质诱导的界面水分子的重组是区域无关的。数据的线性允许计算每种脂类的表面偶极矩。.MU..perp的值。对于一系列含油酰基甘油，二油酰磷脂酰胆碱和二油酰磷脂酰乙醇胺表现出酰基甘油酯基团.MU.Perp.‘S，这与此类脂质的已知构象性质大体一致。其值为132md和252md，分别为甘油酯和扭链构象。S用这些值与同系物计算的结果进行比较，证实了MU..perp的近似独立性。形成脂肪链长度，并允许识别可能存在构象或取向差异的异常。值得注意的是，二植酰磷脂酰胆碱表现出45%的大.MU..perp。比预想的要好。在.MU..PERP中的差异。脂类之间的差异可以估计脂类新陈代谢和交换的电子后果。计算表明，由二酰基甘油磷胆碱或二酰基甘油磷酸肌醇生成1，2-二酰基甘油的反应应分别产生-127 mV和+42 mV的表面电位变化。因此，对于依赖于表面电位的过程而言，这两种磷脂不是简单的二酰甘油的替代来源。
Surface potential-surface pressure-area isotherms at the argon-buffer interface have been determined for 38 lipid species comprising 19 chemical classes. These lipids all exhibited a finite range of liquid-expanded surface pressure-area behavior. For most species, the linearity of surface potential with reciprocal area was excellent, but nonzero intercepts were obtained. This suggests a lipid-induced reorganization of interfacial water molecules which is area independent. The linearity of the data permits calculation of the surface dipole moment, .mu..perp., for each lipid. The values of .mu..perp. for a series of oleoyl-containing acylglycerols, dioleoyl phosphatidylcholine, and dioleoyl phosphatidylethanolamine exhibit acylglycerol ester group .mu..perp.''s which are generally consistent with known conformational properties of such lipids. The values are 132 mD for the perpenicular oleoyl glycerol-ester group and 252 mD for that in the kinked-chain conformation. Comparison of .mu..perp.''s calculated using these values with homologues confirms the approximate independence of .mu..perp. form aliphatic chain length and permits identification of exceptions with possible conformational or orientational differences. Notably, diphytanoyl phosphatidylcholine shows a 45% larger .mu..perp. than predicted. Differences in .mu..perp. among lipid classes allow estimation of the electrical consequences of lipid metabolism and exchange. Calculations show that reactions such as the generation of 1,2-diacylglycerol from diacyl glycerophosphocholine or diacyl glycerophosphoinositol should produce surface potential changes of -127 and +42 mV, respectively. Thus, the two phospholipids are not simply alternative sources of diacylglycerol with respect to processes dependent on surface potential.