Role of cholesterol in the structural order of lens membrane lipids
Role of cholesterol in the structural order of lens membrane lipids
复制标题
DOI：
10.1006/exer.1996.0023
复制
发表时间：
1996-02-01
影响因子：
3.4
通讯作者：
Lamba, OP
中科院分区：
文献类型：
--
作者：
Borchman, D;Cenedella, RJ;Lamba, OP
胆固醇可使磷脂有序或无序。胆固醇对透镜膜脂质结构顺序的生理贡献被确定。用薄层层析法分离牛透镜核和皮质组织中的胆固醇和磷脂。胆固醇对烃链的反式向左转变的影响通过测量CH2红外伸缩带频率来评估，因为胆固醇被添加回磷脂中。虽然核脂质的相对胆固醇水平远高于皮质（59与36摩尔%，分别），未分级的核和皮质脂质的结构顺序在生理温度下是相似的。胆固醇添加到没有胆固醇的脂质产生了尖锐的双相效应的核脂质的结构顺序，增加反式构象从56%的0摩尔%的胆固醇的74%，18%的胆固醇，41%的反式在59摩尔%的胆固醇。胆固醇添加产生了浅的双相变化的百分比反式构象的皮质脂质。最大顺序（约40%的反式构象）被认为是在胆固醇水平等于完整的皮质脂质（36摩尔%）。胆固醇的生理作用是增加皮层膜脂质的结构有序性，降低核脂质的结构有序性。最终结果是皮层和核膜的结构顺序相似。我们认为皮质和核脂质对胆固醇的不同反应与这两个透镜区域之间的磷脂组成差异有关。在没有胆固醇的情况下，核磷脂比皮质磷脂有序得多。(C)1996年学术出版社
Cholesterol may order or disorder phospholipids. The physiological contribution of cholesterol to the structural order of lens membrane lipids was determined. Cholesterol and phospholipid from bovine lens nuclear and cortical tissue were separated by thin layer chromatography. The effect of cholesterol upon the trans to gauche transition of the hydrocarbon chains was assessed by measuring CH2 infrared stretching band frequencies as cholesterol was added back to the phospholipids. Although the relative cholesterol level of nuclear lipid was much higher than that of the cortex (59 vs. 36 mol%, respectively), the structural order of unfractionated nuclear and cortical lipids were similar at physiological temperature. Cholesterol added to lipids devoid of cholesterol produced a sharp biphasic effect on the structural order of nuclear lipids, increasing the trans conformation from 56% of 0 mol% cholesterol to 74% at 18% cholesterol to 41% trans at 59 mol% cholesterol. Cholesterol addition produced a shallow biphasic change in the percentage trans conformation of cortical lipids. Maximum order (about 40% trans conformation) was seen at a cholesterol level equal to that of intact cortical lipid (36 mol%). The physiological role of cholesterol is to increase the structural order of cortical membrane lipid and decrease order in nuclear lipid. The net result is a similarity in the structural order of cortical and nuclear membrane. We suggest that the different response of cortical and nuclear lipids to added cholesterol is linked to differences in the phospholipid composition between these two lens regions. In the absence of cholesterol, nuclear phospholipids are much more highly ordered than those of the cortex. (C) 1996 Academic Press Limited