Lucas C T, Call F L, Williams W J
J Clin Invest. 1970 Oct;49(10):1949-55. doi: 10.1172/JCI106414.
Homogenates of human platelets can mediate the synthesis of phosphatidylinositol from myoinositol and cytidine diphosphate diglyceride. The cytidine diphosphate diglyceride: myoinositol, phosphatidyl transferase activity is particulate-bound, and the highest specific activity is found in the membrane fraction. The production of phosphatidylinositol is decreased by sulfhydryl-binding agents, and the addition of thiols to the platelet homogenates increases the enzymatic activity. The reaction exhibits a pH optimum of 8.5-9.0. Divalent cations stimulate the reaction, and manganous chloride was the most effective of those investigated. The K(m) of the enzyme for myoinositol is 0.27 mM, and the K(m) for cytidine diphosphate diglyceride is 0.53 mM. The enzymatic activity of platelets isolated from patients with several diseases known to interfere with platelet clotpromoting function is similar to the enzymatic activity of platelets from normal donors.
人血小板匀浆可介导由肌醇和胞苷二磷酸甘油二酯合成磷脂酰肌醇。胞苷二磷酸甘油二酯：肌醇磷脂酰转移酶活性与颗粒结合，在膜部分中发现最高的比活性。巯基结合剂可降低磷脂酰肌醇的产生，向血小板匀浆中添加硫醇可增加酶活性。该反应的最适pH为8.5 - 9.0。二价阳离子刺激该反应，在所研究的离子中氯化锰最为有效。该酶对肌醇的米氏常数（K(m)）为0.27 mM，对胞苷二磷酸甘油二酯的K(m)为0.53 mM。从已知会干扰血小板促凝功能的几种疾病患者中分离出的血小板的酶活性与正常供体血小板的酶活性相似。
