Calorimetric evidence for phase transitions in spin-label lipid bilayers.
Calorimetric evidence for phase transitions in spin-label lipid bilayers.
复制标题
自旋标记脂质双层中相变的量热证据。
DOI：
10.1021/bi00263a038
复制
发表时间：
1982
期刊：
影响因子：
2.9
通讯作者：
Gaffney,BJ
中科院分区：
文献类型：
--
作者：
Chen,SC;Sturtevant,JM;Conklin,K;Gaffney,BJ
Shaw-Chen Chen, Julian M. Sturtevant， Kathryn Conklin和Betty Jean Gaffney*摘要：用Privalov高灵敏度差示扫描量热计研究了纯自旋标记磷脂酰胆碱在水溶液缓冲液中的分散。所研究的脂质为混合链脂质，其中甘油的C-2具有硬脂酸的自旋标记衍生物，Cl处的脂肪酸基团为棕榈酸酯。在30.3-30.7℃时，在硬脂酸链的极端附近标记的磷脂酰胆碱（标记在C-5处）观察到一个明确的相变。脂质自旋标记在硬脂酸末端甲基附近（标记在C- 16）也观察到一个急剧的转变（32-34℃），但该脂质的热力学参数强烈依赖于样品的历史。在使用脂质探针的研究中，对有或没有蛋白质成分的磷脂-磷脂双分子层的物理化学有了相当深入的了解。这些探针可能包含用于电子类磁共振（EPR） 1研究的顺磁性基团（Seelig, 1970; Hubbell & McConnell, 1971; Gaffney & McConnell, 1974），荧光测量的色电话(Sklar等人，1975；
Shaw-Chen Chen, Julian M. Sturtevant, Kathryn Conklin, and Betty Jean Gaffney* abstract: Dispersions of pure, spin-label phosphatidylcholines in aqueous buffer have been investigated with the Privalov high-sensitivity differential scanning calorimeter. The lipids studied are mixed-chain ones in which C-2 of glycerol bears a spin-label derivative of stearic acid and the fatty acid group at Cl is palmitate. A well-defined phase transition is observed at 30.3-30.7 C for the phosphatidylcholine labeled near the polar end of the stearate chain (label at C-5). A sharp transition (32-34 C) is also observed for the lipid spin-labeled near the terminal methyl of stearate (label at C-l6), but the thermodynamic parameters for this lipid depend strongly on the history of the sample. Calorimetric evidence for hysteresis (Considerable insight into the physical chemistry of phos-pholipid bilayers, with and without protein components, has been obtained in studies which employ lipid probes. These probes maycontain paramagnetic groups for electron para-magnetic resonance(EPR) 1 studies (Seelig, 1970; Hubbell & McConnell, 1971; Gaffney & McConnell, 1974), chromo-phores for fluorescence measurements (Sklar et al., 1975;