Richter F, Rapp G, Finegold L
European Molecular Biology Laboratory at DESY, Notkestrasse 85, D-22603 Hamburg, Germany.
Phys Rev E Stat Nonlin Soft Matter Phys. 2001 May;63(5 Pt 1):051914. doi: 10.1103/PhysRevE.63.051914. Epub 2001 Apr 26.
A binary mixture of dimyristoylphosphatidylcholine (DMPC) and cholesterol displays a fluid miscibility gap under excess water conditions. Effects due to the imperfect miscibility of the two amphiphiles are studied near to and far from thermodynamic equilibrium by time-resolved small angle x-ray diffraction. The experiment discloses that this mixture phase separates when leaving the miscibility gap upon heating, a transition that is not included in current phase diagrams. This transition appears to be reversible and shows a temperature hysteresis of only a few degrees. We suggest a model in which the transition is driven with increasing temperature by a movement of the cholesterol away from the hydrophilic-hydrophobic interface toward the hydrophobic core of the bilayer.
在过量水条件下，二肉豆蔻酰磷脂酰胆碱（DMPC）和胆固醇的二元混合物呈现出流体混溶间隙。通过时间分辨小角X射线衍射，研究了这两种两亲物在接近和远离热力学平衡时因不完全混溶而产生的影响。实验表明，该混合物在加热时离开混溶间隙时会发生相分离，这一转变未包含在当前的相图中。这种转变似乎是可逆的，并且仅显示出几度的温度滞后。我们提出了一个模型，其中随着温度升高，胆固醇从亲水-疏水界面向双层疏水核心移动，从而驱动了这一转变。
