Deuterium magnetic resonance of selectively deuterated cholesteryl esters in phosphatidylcholine vesicles.
Deuterium magnetic resonance of selectively deuterated cholesteryl esters in phosphatidylcholine vesicles.
复制标题
磷脂酰胆碱囊泡中选择性氘代胆固醇酯的氘磁共振。
作者：
H. Gorrissen;A. P. Tulloch;R. J. Cushley
对鸡蛋磷脂酰胆碱 (PC) 单层囊泡中的选择性氘化胆固醇棕榈酸酯 (CP) 和胆固醇硬脂酸酯 (CS) 进行了氘核磁共振 (2H NMR) 实验。鸡蛋 PC 囊泡含有高达 5 mol% 的酯，平均直径为 22 nm。添加 20 mol% 胆固醇将双层中胆固醇酯的溶解度降低至约 2-3 mol%，但囊泡大小保持不变。 2H MNR 结果表明，无论存在还是不存在胆固醇，CP 和 CS 的酰基链都高度无序（SCD 小于 0.10）。鸡蛋 PC 囊泡中选择性氘化 CP 和 CS 的 T1 测量表明，酯分子的高度无序性与低反式链异构化速率的增加无关。提供了分子运动和方向方面的低阶参数的可能解释。
Deuterium nuclear magnetic resonance (2H NMR) experiments have been performed on selectively deuterated cholesteryl palmitate (CP) and cholesteryl stearate (CS) in egg phosphatidylcholine (PC) unilamellar vesicles. Egg PC vesicles were found to incorporate up to 5 mol % ester and to have a mean diameter of 22 nm. Addition of 20 mol % cholesterol decreased the solubility of cholesteryl ester in the bilayer to approximately 2-3 mol %, but the vesicle size remained unchanged. The 2H MNR results reveal that the acyl chains of CP and CS are highly disordered (SCD less than 0.10) both in the presence and in the absence of cholesterol. T1 measurements for selectively deuterated CP and CS in egg PC vesicles indicate that the high degree of disorder of the ester molecule is not associated with an increase in the rate of gauche-trans chain isomerization. Possible explanations for the low order parameters in terms of molecular motions and orientations are offered.