Stillwell W, Dallman T, Dumaual A C, Crump F T, Jenski L J
Department of Biology, Indiana University, Purdue University at Indianapolis 46202-5132, USA.
Biochemistry. 1996 Oct 15;35(41):13353-62. doi: 10.1021/bi961058m.
The techniques of differential scanning calorimetry, fluorescence of merocyanine 540, fluorescence polarization of 1,6-diphenyl-1,3,5-hexatriene, proton permeability, and lipid peroxidation are used to compare the perturbations of cholesterol and alpha-tocopherol on lipid bilayer membranes composed of different phosphatidylcholines containing stearic acid in the sn-1 position and an unsaturated fatty acid (either oleic, alpha-linolenic, gamma-linolenic, or docosahexaenoic acid) in the sn-2 position. It is concluded that the structural roles of cholesterol and alpha-tocopherol may be similar with membranes composed of some phosphatidylcholines but are clearly different with membranes composed of other related phosphatidylcholines. alpha-Tocopherol exerts a much larger effect than cholesterol on membranes rich in polyunsaturated fatty acids that have their initial double bond before the delta 9 position. Cholesterol interacts more favorably with fatty acids that do not have an double bond before the delta 9 position. The membrane structural effects are explained in terms of the larger size of the sterol ring structure of cholesterol compared to the smaller chromanol ring of the alpha-tocopherol.
采用差示扫描量热法、部花青540荧光法、1,6-二苯基-1,3,5-己三烯荧光偏振法、质子渗透性和脂质过氧化技术，比较胆固醇和α-生育酚对脂质双层膜的扰动，这些脂质双层膜由在sn-1位含有硬脂酸且在sn-2位含有不饱和脂肪酸（油酸、α-亚麻酸、γ-亚麻酸或二十二碳六烯酸）的不同磷脂酰胆碱组成。得出的结论是，胆固醇和α-生育酚的结构作用在某些磷脂酰胆碱组成的膜中可能相似，但在其他相关磷脂酰胆碱组成的膜中明显不同。α-生育酚对富含多不饱和脂肪酸且其初始双键在δ9位之前的膜的作用比胆固醇大得多。胆固醇与在δ9位之前没有双键的脂肪酸相互作用更有利。根据胆固醇的甾醇环结构比α-生育酚的较小色满环更大，来解释膜结构效应。
