MOE Key Laboratory of Bioorganic Phosphorus Chemistry & Chemical Biology, Department of Chemistry, Tsinghua University, Beijing 100084, China.
J Am Soc Mass Spectrom. 2021 Feb 3;32(2):560-568. doi: 10.1021/jasms.0c00407. Epub 2021 Jan 14.
Phosphatidylcholines (PCs) are the major structural components of the plasma membrane of mammalian cells, while lysophosphatidylcholines (LPCs) are critical intermediates in lipid remodeling. Conventional tandem mass spectrometric (MS) methods via collision-induced dissociation (CID) are blind to intrachain modifications such as the location of the carbon-carbon double bond (C═C) and methyl branching point. In this study, we demonstrate that almost complete structural information can be inferred from a single MS CID spectrum of the bicarbonate anion adducts of PC or LPC ([M + HCO]), including the identity of the headgroup, composition of fatty acyl chains, their -positions, the location of C═C, and the point of methyl branching in fatty acyls. We have integrated this MS CID method onto liquid chromatography for the analysis LPCs in human plasma, revealing the existence of multiple -isomers, branched chain isomers, and C═C location isomers of LPC.
磷脂酰胆碱（PCs）是哺乳动物细胞膜的主要结构成分，而溶血磷脂酰胆碱（LPCs）是脂质重塑的关键中间产物。传统的串联质谱（MS）方法通过碰撞诱导解离（CID）对链内修饰（如碳-碳双键（C═C）和甲基支链点的位置）是盲目的。在这项研究中，我们证明了几乎可以从 PC 或 LPC ([M + HCO]) 的碳酸氢盐加合物的单个 MS CID 光谱中推断出完整的结构信息，包括头部基团的身份、脂肪酸链的组成、它们的 -位、C═C 的位置以及脂肪酸中甲基支链的位置。我们已经将这种 MS CID 方法整合到液相色谱中，用于分析人血浆中的 LPC，揭示了 LPC 存在多种 -异构体、支链异构体和 C═C 位置异构体。
