The phase transition properties of aqueous suspensions of a series of nonhydrated (not heated above room temperature) and hydrated 1,2 diacylphosphatidylethanolamines (PE's) have been examined by high sensitivity differential scanning calorimetry at scan rates of 0.02-1.0 K min-1. At all scan rates nonhydrated PE's show a single asymmetric transition curve of excess heat capacity as a function of temperature. Multilamellar dispersions of hydrated PE's, however, exhibit transitions with fine structure, which can be fitted as the sum of three two-state component transitions, at scan rates of 0.02-0.1 K min-1, but give only a single asymmetric transition at 1.0 K min-1. At all scan rates the transition(s) of hydrated samples occur at lower temperatures than those of nonhydrated samples. One of the component transitions of hydrated PE's may be analogous to the pretransition that occurs in 1,2 diacylphosphatidylcholines.
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机译:已通过高灵敏度差示扫描量热法以0.02-1.0 K min-1的扫描速率检查了一系列非水合(未加热至室温以上)和水合1,2-二酰基磷脂酰乙醇胺(PE's)的水悬浮液的相变特性。在所有扫描速率下,非水合PE均显示出过量热容量随温度变化的单个不对称过渡曲线。但是,水合PE的多层分散体显示出具有精细结构的跃迁,可以将其作为三个两态组分跃迁的总和,扫描速率为0.02-0.1 K min-1,但在1.0时仅给出一个不对称跃迁K min-1。在所有扫描速率下,水合样品的转变都发生在比非水合样品更低的温度下。水合PE的组分转变之一可能类似于在1,2二酰基磷脂酰胆碱中发生的预转变。
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