Baker Paul R S, Armando Aaron M, Campbell J Larry, Quehenberger Oswald, Dennis Edward A
AB SCIEX, Redwood Shores, CA.
Department of Chemistry and Biochemistry, University of California San Diego, La Jolla, CA Department of Pharmacology, University of California San Diego, La Jolla, CA.
J Lipid Res. 2014 Nov;55(11):2432-42. doi: 10.1194/jlr.D051581. Epub 2014 Sep 15.
Phospholipids serve as central structural components in cellular membranes and as potent mediators in numerous signaling pathways. There are six main classes of naturally occurring phospholipids distinguished by their distinct polar head groups that contain many unique molecular species with distinct fatty acid composition. Phospholipid molecular species are often expressed as isobaric species that are denoted by the phospholipid class and the total number of carbon atoms and double bonds contained in the esterified fatty acyl groups (e.g., phosphatidylcholine 34:2). Techniques to separate these molecules exist, and each has positive and negative attributes. Hydrophilic interaction liquid chromatography uses polar bonded silica to separate lipids by polar head group but not by specific molecular species. Reversed phase (RP) chromatography can separate by fatty acyl chain composition but not by polar head group. Herein we describe a new strategy called differential ion mobility spectrometry (DMS), which separates phospholipid classes by their polar head group. Combining DMS with current LC methods enhances phospholipid separation by increasing resolution, specificity, and signal-to-noise ratio. Additional application of specialized information-dependent acquisition methodologies along with RP chromatography allows full isobaric resolution, identification, and compositional characterization of specific phospholipids at the molecular level.
磷脂是细胞膜的核心结构成分，也是众多信号通路中的强效介质。天然存在的磷脂主要有六大类，根据其独特的极性头部基团区分，这些头部基团包含许多具有不同脂肪酸组成的独特分子种类。磷脂分子种类通常表示为等压种类，由磷脂类别以及酯化脂肪酰基中所含碳原子和双键的总数表示（例如，磷脂酰胆碱34:2）。存在分离这些分子的技术，每种技术都有其优缺点。亲水相互作用液相色谱法使用极性键合硅胶按极性头部基团而非特定分子种类分离脂质。反相（RP）色谱法可按脂肪酰链组成分离，但不能按极性头部基团分离。在此，我们描述了一种称为差分离子迁移谱（DMS）的新策略，它按磷脂的极性头部基团分离磷脂类别。将DMS与当前的液相色谱方法相结合，通过提高分辨率、特异性和信噪比来增强磷脂分离。结合RP色谱法，进一步应用专门的信息依赖型采集方法，可在分子水平上实现特定磷脂的全等压分辨率、鉴定和组成表征。
