Kawamoto T, Akino T, Nakamura M, Mori M
Biochim Biophys Acta. 1980 Jul 14;619(1):35-47.
Membrane fractions, particularly microsomes and bile canalicular membranes, isolated from rat liver were examined, in order to elucidate the site of a subpool of phosphatidylcholine destined for bile in the liver cell which was demonstrated in a previous paper (Kawamoto, T., Okano, G. and Akino, T. (1980) Biochim. Biophys. Acta 619, 20--34). 1. The bile canalicular membranes isolated from rat liver were not contaminated by other membranes when examined by membrane marker enzymes, and showed typical membrane structure, when examined by electron microscopy. The activity of DCPcholine : diacylglycerol cholinephosphotransferase was almost absent from the bile canalicular membranes and acyl CoA : 1-acyl-sn-glycero-3-phosphocholine acyltransferase activity was 17% of that found in the microsomes. 2. The molecular class composition of phosphatidylcholine was similar in the bile canalicular membranes and microsomes. The proportion of palmitoyl and stearoyl species in the major molecular classes was also similar in both membrane types. 3. In the in vivo experiments with [2-(3H)]glycerol, the specific radioactivity of phosphatidylcholine and its species such as palmitoyl-linoleoyl species in the bile canalicular membranes were significantly higher than that in other membranes. When compared with the specific radioactivity of phosphatidylcholine species in bile that in the bile canalicular membranes was also distinctly higher.
为了阐明肝细胞中注定要进入胆汁的磷脂酰胆碱亚池的位置（在之前的一篇论文中已得到证实（Kawamoto, T., Okano, G. and Akino, T. (1980) Biochim. Biophys. Acta 619, 20--34）），对从大鼠肝脏分离得到的膜组分，特别是微粒体和胆小管膜进行了研究。1. 通过膜标记酶检测，从大鼠肝脏分离得到的胆小管膜未被其他膜污染，并且通过电子显微镜检查显示出典型的膜结构。胆小管膜中几乎不存在二氯磷酸胆碱：二酰基甘油胆碱磷酸转移酶的活性，而酰基辅酶A：1-酰基-sn-甘油-3-磷酸胆碱酰基转移酶的活性是微粒体中该酶活性的17%。2. 胆小管膜和微粒体中磷脂酰胆碱的分子种类组成相似。在这两种膜类型中，主要分子种类中棕榈酰和硬脂酰种类的比例也相似。3. 在使用[2-(3H)]甘油进行的体内实验中，胆小管膜中磷脂酰胆碱及其种类（如棕榈酰-亚油酰种类）的比放射性显著高于其他膜中的比放射性。与胆汁中磷脂酰胆碱种类的比放射性相比，胆小管膜中的比放射性也明显更高。
