Gruenewald B, Blume A, Watanabe F
Biochim Biophys Acta. 1980 Mar 27;597(1):41-52. doi: 10.1016/0005-2736(80)90148-0.
Pressure-jump experiments were performed on vesicles and liposomes of dimyristoyl phosphatidylcholine and dipalmitoyl phosphatidylcholine following the time course of solution turbidity. For both lipids two relaxation effects were evaluated the time constants of which exhibit clear maxima at the mid-point of the phase transition. The time constants lie for vesicles in the 100 microseconds and 1 ms ranges and for liposomes in the 1 ms and 10 ms ranges. The processes are slightly faster for dimyristoyl phosphatidylcholine than for dipalmitoyl phosphatidylcholine. All relaxation times are concentration-independent. The time constant and amplitude behaviours indicate that all processes are cooperative in agreement with previous interpretations. It is demonstrated that cooperative units can be evaluated from the relaxation amplitudes. These are of the same order of magnitude as those obtained from static experiments. On the grounds of the present kinetic investigation we can state that the application of the linear Ising model to two-dimensional processes as attempted for the static lipid phase transition is inadequate.
在二肉豆蔻酰磷脂酰胆碱和二棕榈酰磷脂酰胆碱的囊泡和脂质体上进行了压力跳跃实验，跟踪溶液浊度随时间的变化过程。对于这两种脂质，评估了两种弛豫效应，其时间常数在相变中点处呈现明显的最大值。囊泡的时间常数在100微秒和1毫秒范围内，脂质体的时间常数在1毫秒和10毫秒范围内。二肉豆蔻酰磷脂酰胆碱的过程比二棕榈酰磷脂酰胆碱的过程稍快。所有弛豫时间均与浓度无关。时间常数和振幅行为表明，所有过程都是协同的，这与先前的解释一致。结果表明，可以从弛豫振幅评估协同单元。这些与从静态实验获得的协同单元数量级相同。基于目前的动力学研究，我们可以指出，将线性伊辛模型应用于二维过程（如尝试用于静态脂质相变）是不充分的。
