Duppel W, Dahl G
Biochim Biophys Acta. 1976 Mar 19;426(3):408-17. doi: 10.1016/0005-2736(76)90386-2.
(1) Rat liver microsomes were studied by freeze-fracture electron microscopy. The distribution of membrane-associated particles indicated the right-side-out orientation of microsomal vesicles. Studies at different temperatures were performed. At 30 degrees C membrane-associated particles are randomly distributed on membrane A-faces, while aggregations of particles are observed at 4 degrees C. (2) Aggregation is dependent on the cooling rates. It can be prevented by shock-freezing. (3) Particle aggregation is also prevented by cholesterol, added to the microsomes in equal molar ratio to the microsomal phospholid content. (4) These findings suggest that particle aggregation is caused by a partial freezing-out of phospholipid molecules during the phase transition from the liquid-crystalline to the gel state. (5) The results are discussed with respect to an observed increase in activation energy of microsomal drug monooxygenation at lower temperature.
（1）通过冷冻断裂电子显微镜对大鼠肝脏微粒体进行了研究。膜相关颗粒的分布表明微粒体囊泡呈外翻取向。进行了不同温度下的研究。在30℃时，膜相关颗粒随机分布在A面膜上，而在4℃时观察到颗粒聚集。（2）聚集取决于冷却速率。可通过快速冷冻防止聚集。（3）微粒体中加入与微粒体磷脂含量等摩尔比的胆固醇也可防止颗粒聚集。（4）这些发现表明，颗粒聚集是由磷脂分子在从液晶态到凝胶态的相变过程中部分冻结析出所致。（5）结合在较低温度下观察到的微粒体药物单加氧酶激活能增加的现象对结果进行了讨论。
