Structural studies on phophatidylcholine-cholesterol mixed vesicles.
Structural studies on phophatidylcholine-cholesterol mixed vesicles.
复制标题
DOI：
10.1021/bi00686a012
复制
发表时间：
1975-07
期刊：
影响因子：
2.9
通讯作者：
G. C. Newman;C. Huang
中科院分区：
文献类型：
--
作者：
G. C. Newman;C. Huang
在4度氮气气氛下，鸡蛋卵磷脂在不同量的胆固醇存在下进行超声照射，然后在Sepharose 4B柱上进行分子筛色谱，制备了均匀的单壁磷脂酰胆碱-胆固醇混合囊泡。对这些系统进行的物理化学研究包括沉降速度、扩散、部分比容、特性粘度和捕获体积测量，可以估计磷脂酰胆碱和胆固醇二元混合物的重量-平均囊泡重量、囊泡形状和双层膜厚度。用两种不同的方法计算囊泡水合作用，在胆固醇浓度为0.32摩尔分数时，两者的一致性很好。观察到，随着胆固醇含量的增加，结构参数的变化缓慢，直到0.3摩尔分数左右，在此胆固醇含量以上发生相对突然的结构改变。这种突然的结构变化与内外双层表面脂质组成的不对称分布是一致的。
The homogeneous, single-walled phosphatidylcholine-cholesterol mixed vesicles were prepared by ultrasonic irradiation of egg phosphatidylcholine in the presence of various amounts of cholesterol in solution at 4 degrees under a nitrogen atmosphere followed by molecular sieve chromatography on a Sepharose 4B column. Physicochemical studies performed on these systems invluding sedimentation velocity, diffusion, partial specific volume, intrinsic viscosity, and trapped volume measurements allowed estimation of the weight-average vesicle weight, the vesicle shape, and bilayer membrane thickness of the binary mixture of phosphatidylcholine and cholesterol. Vesicle hydration was calculated using two different methods and the agreement between them was excellent up to cholesterol concentration of 0.32 mole fraction. It was observed that the structural parameters change slowly with increasing cholesterol content up to around 0.3 mole fraction and a relatively abrupt structural alteration occurs above this cholesterol content. This abrupt structural change is consistent with the asymmetrical distribution of lipid composition between the inner and outer bilayer face.