Trahms L, Klabe W D, Boroske E
Biophys J. 1983 Jun;42(3):285-93. doi: 10.1016/S0006-3495(83)84396-3.
The three phases of dipalmitoylphosphatidylcholine-water dispersions, occurring below the main transition are studied by a moment analysis of 1H-nuclear magnetic resonance (NMR) spectra. The subtransition, recently detected by Chen, S. C., J. M. Sturtevant, and B. J. Gaffney, 1980, Pro. Natl. Acad. Sci. USA, 77:5060-5063, is characterized by a sharp drop in the second moment at 12 degrees C as a result of increasing the temperature. Interesting features of this phase transition are a hysteresis of 11 K and extremely slow kinetics. It is interpreted as the onset of a flip-flop of the hydrocarbon chains about their long axis. At the pretransition, this type of motion is assumed to change into a fast rotation. The proposed models for the three phases are confirmed by computer calculations of theoretical values for the second and fourth moments of the corresponding NMR signals.
通过对1H核磁共振(NMR)谱进行矩分析,研究了二棕榈酰磷脂酰胆碱 - 水分散体在主要转变温度以下出现的三个阶段。陈、S.C.、J.M.斯特蒂文特和B.J.加夫尼于1980年在《美国国家科学院院刊》第77卷第5060 - 5063页首次检测到的亚转变,其特征是由于温度升高,在12摄氏度时第二矩急剧下降。该相变的有趣特征是11K的滞后现象和极其缓慢的动力学。它被解释为烃链围绕其长轴发生翻转的开始。在预转变时,这种运动被认为转变为快速旋转。通过对相应NMR信号的第二和第四矩的理论值进行计算机计算,证实了所提出的三个阶段的模型。