分子运动与相变。几种卵磷脂的核磁共振弛豫时间研究。
Molecular motions and phase transitions. NMR relaxation times studies of several lecithins.
作者信息
Bar-Adon R, Gilboa H
出版信息
Biophys J. 1981 Mar;33(3):419-34. doi: 10.1016/S0006-3495(81)84904-1.
The spin-lattice relaxation time, T1, and the dipolar energy relaxation time, TD, were measured as a function of temperature. The materials studied were samples of anhydrous L-dipalmitoyl lecithin, DL-dipalmitoyl lecithin, L-dimyristoyl lecithin, DL-dimyristoyl lecithin and their monohydrates, and of anhydrous egg yolk lecithin. It is shown that TD is a much more sensitive parameter than T1 for the determination of the Chapman phase transition. Comparison between T1 and TD provides information about new types of slow molecular motions below and above the phase transition temperature. It is suggested that the relaxation mechanisms for T1 and TD in the gel phase are governed by segmental motion in the phospholipid molecule. A new metastable phase was detected in dimyristoyl lecithin monohydrates. This phase could only be detected from the dipolar energy relaxation times.
测量了自旋 - 晶格弛豫时间T1和偶极能量弛豫时间TD随温度的变化。所研究的材料是无水L - 二棕榈酰卵磷脂、DL - 二棕榈酰卵磷脂、L - 二肉豆蔻酰卵磷脂、DL - 二肉豆蔻酰卵磷脂及其一水合物以及无水蛋黄卵磷脂的样品。结果表明，在确定查普曼相变时，TD是比T1更敏感的参数。T1和TD之间的比较提供了有关相变温度以下和以上新型慢分子运动的信息。有人认为，凝胶相中T1和TD的弛豫机制受磷脂分子中链段运动的控制。在二肉豆蔻酰卵磷脂一水合物中检测到一个新的亚稳相。这个相只能从偶极能量弛豫时间中检测到。
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