Jolliot A, Justin A M, Bimont E, Mazliak P
Laboratoire de Physiologie Cellulaire, ERA 323, Université Pierre et Marie Curie, 75230 Paris cédex 05, France.
Plant Physiol. 1982 Jul;70(1):206-10. doi: 10.1104/pp.70.1.206.
Cytidine-diphospho-choline diacyl-glycerol phosphorylcholine phosphotransferase activity was demonstrated in potato (Solanum tuberosum L.) microsomes and the incorporation of cytidine-diphospho[(14)C]choline into phosphatidylcholine was characterized by the time course of (14)C incorporation and the effect of microsomal protein concentration on choline incorporation.Potato microsomes were progressively delipidated by treatments (2 min at 0 degrees C) with increasing amounts of phospholipase C from Bacillus cereus. A decrease in choline phosphotransferase activity was observed in parallel with the progressive hydrolysis of membrane phospholipids. A 70% (or more) phospholipid hydrolysis provoked the total inactivation of the enzyme.Adding back exogenous phospholipids (in the form of liposomes) to phospholipase C-treated membranes restored the enzymic activity. Restoration could be obtained with egg yolk phospholipids as well as with potato phospholipids. Restoration was time dependent and completed after 10 minutes; restoration was also dependent on the quantity of liposomes added to lipid-depleted membranes: the best restorations were obtained with 1 to 2.5 milligrams of phospholipid per mg of microsomal protein; higher phospholipid to protein ratios were less efficient or inhibitory.These results clearly demonstrate the phospholipid dependence of the cytidine-diphospho-choline phosphotransferase from potato microsomes.
在马铃薯（Solanum tuberosum L.）微粒体中证实了胞苷二磷酸胆碱二酰甘油磷酸胆碱磷酸转移酶活性，并且通过（14）C掺入的时间进程以及微粒体蛋白浓度对胆碱掺入的影响来表征胞苷二磷酸[（14）C]胆碱掺入磷脂酰胆碱的过程。用来自蜡状芽孢杆菌的越来越多的磷脂酶C在0℃处理（2分钟），使马铃薯微粒体逐渐脱脂。观察到胆碱磷酸转移酶活性的降低与膜磷脂的逐渐水解同时发生。70％（或更多）的磷脂水解导致该酶完全失活。将外源性磷脂（以脂质体的形式）添加回经磷脂酶C处理的膜中可恢复酶活性。用蛋黄磷脂以及马铃薯磷脂都可以实现恢复。恢复是时间依赖性的，10分钟后完成；恢复还取决于添加到脂质耗尽膜中的脂质体数量：每毫克微粒体蛋白加入1至2.5毫克磷脂可获得最佳恢复效果；更高的磷脂与蛋白比例效率较低或具有抑制作用。这些结果清楚地证明了马铃薯微粒体中胞苷二磷酸胆碱磷酸转移酶对磷脂的依赖性。
