Yager P, Peticolas W L
Biochim Biophys Acta. 1982 Jun 28;688(3):775-85. doi: 10.1016/0005-2736(82)90291-7.
The sensitivity of the melting transition temperature of aqueous dispersions of dipalmitoyl- and distearoylphosphatidylcholine to hydrostatic pressure is used to allow measurement of the rates of isothermal freezing and melting of the lipids by rapidly changing the pressure. The degree of order of the lipids is measured by monitoring a ratio of two points in the Raman spectrum of the lipids which changes sharply at the melting temperature. Use of this Raman order ratio allows correlation between the order of the sample and the rates of transition in a manner which is impossible by monitoring only turbidity. Our longest relaxation times range upwards from a few seconds for both compounds. The freezing rates are slowest when the samples are initially fully melted, and the melting rates are slowest when the samples are initially frozen. These results imply that nucleation of the growing phase dominates the kinetics of both freezing and melting.
利用二棕榈酰磷脂酰胆碱和二硬脂酰磷脂酰胆碱水分散体的熔融转变温度对静水压力的敏感性，通过快速改变压力来测量脂质的等温冷冻和熔融速率。通过监测脂质拉曼光谱中在熔融温度下急剧变化的两个点的比率来测量脂质的有序度。使用这种拉曼有序比率能够以仅监测浊度无法实现的方式，将样品的有序度与转变速率相关联。两种化合物的最长弛豫时间都从几秒向上延伸。当样品最初完全熔化时，冷冻速率最慢；当样品最初冷冻时，熔融速率最慢。这些结果表明，生长相的成核作用主导了冷冻和熔融的动力学过程。
