ENZYMES OF PHOSPHATIDYLCHOLINE SYNTHESIS IN LEMNA, SOYBEAN, AND CARROT
ENZYMES OF PHOSPHATIDYLCHOLINE SYNTHESIS IN LEMNA, SOYBEAN, AND CARROT
复制标题
DOI：
10.1104/pp.88.4.1338
复制
发表时间：
1988-12-01
期刊：
影响因子：
7.4
通讯作者：
MUDD, SH
中科院分区：
文献类型：
--
作者：
DATKO, AH;MUDD, SH
浮萍和悬浮培养胡萝卜的无细胞提取物（Daucus carota L.）催化磷酸乙醇胺、磷酸甲基乙醇胺和磷酸二甲基乙醇胺的S-腺苷甲硫氨酸依赖性N-甲基化;悬浮培养大豆（Glycine max）提取物。磷酸乙醇胺。从每个组织中沉淀的15，000至100，000 g的物质催化磷脂酰甲基乙醇胺和磷脂酰二甲基乙醇胺的S-腺苷甲硫氨酸依赖性N-甲基化，但不催化磷脂酰乙醇胺。每种组织的提取物催化CTP依赖性胞苷酰转移至三种甲基化磷酸乙醇胺衍生物中的每一种，形成相应的CDP衍生物。一些调查的活动的属性的报告。在体内标记实验的基础上，我们提出了（AH Datko，SH Mudd 1988 Plant Physiol 88：854-861）磷脂酰胆碱合成的不同途径，其中在共同的提交步骤磷酸乙醇胺的N-甲基化之后，随后的甲基化几乎仅在浮萍中在磷酸基水平上发生;在大豆中在磷脂酰基水平上发生;并且在胡萝卜中在两个水平上发生。因此，在所调查的活动中，至少那些为拟议途径的运作所需的活动得到了积极的证明。在何种程度上，目前的结果解释这些途径之间的差异进行了讨论，并提供了一个猜测，这些差异可能会出现遗传学。
Cell-free extracts from Lemna and suspension cultured carrot (Daucus carota L.) catalyze S-adenosylmethionine-dependent N-methylations of phosphoethanolamine, phosphomethylethanolamine, and phosphodimethylethanolamine; extracts of suspension cultured soybean (Glycine max). of phosphoethanolamine only. Material pelleted from each tissue between 15,000 and 100,000g catalyzes S-adenosylmethionine-dependent N-methylations of phosphatidylmethylethanolamine and phosphatidyldimethylethanolamine, but not phosphatidylethanolamine. Extracts from each tissue catalyze CTP-dependent cytidylytranfers to each of the three methylated phosphoethanolamine derivatives, forming the corresponding CDP derivatives. Some of the properties of the activities investigated are reported. On the basis of in vivo labeling experiments, we have proposed (AH Datko, SH Mudd 1988 Plant Physiol 88: 854-861) differing pathways for phosphatidylcholine synthesis in which, after a common committing step, N-methylation of phosphoethanolamine, subsequent methylations occur in Lemna almost exclusively at the phospho-base level; in soybean, at the phosphatidyl-base level; and in carrot, at both levels. Thus, among the activities investigated, at least those required for the operation of the proposed pathways have been positively demonstrated. The extent to which the present results explain the differences between these pathways is discussed, and a speculation offered as to how these differences may have arisen phylogenetically.