Cholesterol desorption from clusters of phosphatidylcholine and cholesterol in unilamellar vesicle bilayers during lipid transfer or exchange.
Cholesterol desorption from clusters of phosphatidylcholine and cholesterol in unilamellar vesicle bilayers during lipid transfer or exchange.
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DOI：
10.1021/bi00260a022
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发表时间：
1982-08
期刊：
影响因子：
2.9
通讯作者：
L. McLean;M. Phillips
中科院分区：
文献类型：
--
作者：
L. McLean;M. Phillips
拉里河姆克林 ** 和Michael C.菲利普斯 * 摘要：[4- 14 C]胆固醇从不同酰基链组成和胆固醇浓度的磷脂酰胆碱（PC）小单层囊泡转移的速率已被作为温度的函数，在过量受体囊泡的存在下。胆固醇-PC囊泡含有蛋PC，二肉豆蔻酰-PC（DMPC），或二棕榈酰-PC（DPPC）被用作供体或受体囊泡。一群囊泡含有15mol%的双十六烷基磷酸盐以赋予负电荷，以便供体和受体囊泡可以通过离子交换色谱法快速分离。胆固醇转移率从带负电荷的20摩尔%胆固醇蛋黄PC囊泡到纯蛋PC，DMPC，或DPPC囊泡，随后在一个温度范围内，其中包括凝胶液晶转变温度（Tc）的饱和PC受体囊泡。所有三个体系的Arrhenius图都是线性的和超重叠的，因此在每种情况下的活化能（ε a）都接近88 kJ/mol。因此，当受体囊泡过量时，胆固醇转移的速率和ε a都不依赖于受体囊泡中烃链的物理状态;这与早期的发现一致，即在这种条件下，胆固醇转移的速率取决于胆固醇从供体囊泡双层解吸到水相中的速率。胆固醇从含1mol%胆固醇的供体囊泡中解吸的速率
Larry R. McLean** and Michael C. Phillips* abstract: The rate of [4-14C] cholesterol transfer from phosphatidylcholine (PC) small unilamellar vesicles of different acyl chain compositions and cholesterol concentrations has been followed as a function of temperature in the presence of excess acceptor vesicles. Cholesterol-PC vesicles containing either egg PC, dimyristoyl-PC (DMPC), or dipalmitoyl-PC (DPPC) were used as either donor or acceptor vesicles. One population of vesicles contained 15 mol% dicetyl phosphate to confer a negative charge so that the donor and acceptor vesicles could be separated rapidly by ion-exchange chromatography. The rate of cholesterol transfer from negatively charged 20 mol% cholesterol-egg yolk PCvesicles to pure egg PC, DMPC, or DPPC vesicles was followed over a temperature range which included the gel to liquid-crystal transition temperatures (Tc) of the saturated PC acceptor vesicles. The Arrhenius plots for all three systems are linear and su-perimposable so that the activation energy (£ a) is close to 88 kJ/mol in every case. Thus, neither the rate nor the£ a for transfer is dependent upon the physical state of the hydrocarbon chains in the acceptor vesicles when acceptor vesicles are in excess; this is consistent with earlierfindings that under such conditions the rate of cholesterol transfer is determined by the rate of cholesterol desorption from the donor vesicle bilayer into the aqueous phase. The rate of cholesterol de-sorption from donor vesicles containing 1 mol% cholesterol