Carman G M, Matas J
Can J Microbiol. 1981 Nov;27(11):1140-9. doi: 10.1139/m81-179.
Membrane-associated cytidine 5'-diphospho-1,2-diacyl-sn-glycerol (CDP-diacylglycerol):L-serine O-phosphatidyltransferase (phosphatidylserine synthase, EC2.7.8.8.) and CDP-diacylglycerol:myo-inositol phosphatidyltransferase (phosphatidylinositol synthase, EC 2.7.8.11) were solubilized from the microsomal fraction of Saccharomyces cerevisiae. A variety of detergents were examined for their ability to release phosphatidylserine synthase and phosphatidylinositol synthase activities from the microsome fraction. Both enzymes were solubilized from the microsome fraction with Renex 690 in yield over 80% with increase to specific activity of 1.6-fold. Both solubilized enzymatic activities were dependent on manganese ions and Triton X-100 for maximum activity. The pH optimum for each reaction was 8.0. The apparent Km values for CDP-diacylglycerol and serine for the phosphatidylserine synthase reaction were 0.1 and 0.25 mM, respectively. The apparent Km values for CDP-diacylglycerol and inositol for the phosphatidylinositol synthase reaction were 70 microM and 0.1 mM, respectively. Thioreactive agents inhibited both enzymatic activities. Both solubilized enzymatic activities were thermally inactivated at temperatures above 30 degrees C.
膜相关的胞苷5'-二磷酸-1,2-二酰基-sn-甘油（CDP-二酰甘油）：L-丝氨酸O-磷脂酰转移酶（磷脂酰丝氨酸合酶，EC2.7.8.8）和CDP-二酰甘油：肌醇磷脂酰转移酶（磷脂酰肌醇合酶，EC 2.7.8.11）从酿酒酵母的微粒体部分中溶解出来。研究了多种去污剂从微粒体部分释放磷脂酰丝氨酸合酶和磷脂酰肌醇合酶活性的能力。两种酶都用雷尼替丁690从微粒体部分溶解出来，产率超过80%，比活性提高了1.6倍。两种溶解的酶活性都依赖于锰离子和Triton X-100以达到最大活性。每个反应的最适pH值为8.0。磷脂酰丝氨酸合酶反应中CDP-二酰甘油和丝氨酸的表观Km值分别为0.1和0.25 mM。磷脂酰肌醇合酶反应中CDP-二酰甘油和肌醇的表观Km值分别为70 microM和0.1 mM。硫反应性试剂抑制两种酶活性。两种溶解的酶活性在高于30摄氏度的温度下热失活。
