Boumann Henry A, de Kruijff Ben, Heck Albert J R, de Kroon Anton I P M
Department Biochemistry of Membranes, Centre for Biomembranes and Lipid Enzymology, Institute of Biomembranes, Padualaan 8, 3584 CH Utrecht, The Netherlands.
FEBS Lett. 2004 Jul 2;569(1-3):173-7. doi: 10.1016/j.febslet.2004.05.043.
In yeast, the aminoalcohol phosphotransferases Ept1p and Cpt1p catalyze the final steps in the CDP-ethanolamine and CDP-choline routes leading to phosphatidylethanolamine (PE) and phosphatidylcholine (PC), respectively. To determine how these enzymes contribute to the molecular species profiles of PE and PC in vivo, wild-type, cpt1Delta, and ept1Delta cells were pulse labeled with deuterated ethanolamine and choline. Analysis of newly synthesized PE and PC using electrospray ionization tandem mass spectrometry revealed that PE and PC produced by Ept1p and Cpt1p have different species compositions, demonstrating that the enzymes consume distinct sets of diacylglycerol species in vivo. Using the characteristic phospholipid species profiles produced by Ept1p and Cpt1p as molecular fingerprints, it was also shown that in vivo CDP-monomethylethanolamine is preferentially used as substrate by Ept1p, whereas CDP-dimethylethanolamine and CDP-propanolamine are converted by Cpt1p.
在酵母中，氨基醇磷酸转移酶Ept1p和Cpt1p分别催化通往磷脂酰乙醇胺（PE）和磷脂酰胆碱（PC）的CDP - 乙醇胺途径和CDP - 胆碱途径的最后步骤。为了确定这些酶如何在体内影响PE和PC的分子种类谱，用氘代乙醇胺和胆碱对野生型、cpt1Δ和ept1Δ细胞进行脉冲标记。使用电喷雾电离串联质谱对新合成的PE和PC进行分析，结果显示Ept1p和Cpt1p产生的PE和PC具有不同的种类组成，这表明这些酶在体内消耗不同的二酰基甘油种类。利用Ept1p和Cpt1p产生的特征性磷脂种类谱作为分子指纹，研究还表明，在体内CDP - 单甲基乙醇胺优先被Ept1p用作底物，而CDP - 二甲基乙醇胺和CDP - 丙醇胺则由Cpt1p转化。
