不饱和脂质氮杂环丙烷化反应中间体的原位质谱分析  

In Situ Mass Spectrometric Analysis of Intermediates in Aziridination Reaction of Unsaturated Lipids

作　　者：陈凯祥 魏是奇 陈素明 CHEN Kai-xiang;WEI Shi-qi;CHEN Su-ming(The Institute for Advanced Studies,Wuhan University,Wuhan 430072,China)

机构地区：[1]武汉大学高等研究院,湖北武汉430072

出　　处：《质谱学报》2024年第1期149-156,I0005,共9页Journal of Chinese Mass Spectrometry Society

基　　金：国家自然科学基金(22074111)。

摘　　要：脂质结构决定生物功能,对不饱和脂质C C双键异构体的鉴定面临着挑战。直接的氮-甲基(N-Me)氮杂环丙烷化反应可以对不饱和脂质双键进行衍生,通过与串联质谱结合可实现不饱和脂质双键位置的解析。然而,目前N-Me氮杂环丙烷化反应机理研究尚缺乏中间过程的直接证据。本工作采用一种基于θ毛细管的纳升静电喷雾离子化质谱(nESTASI-MS)分析装置,研究不饱和磷脂酰胆碱的氮杂环丙烷化反应过程,捕获并鉴定了反应过程中的关键中间体,为阐明氮杂环丙烷化反应机理提供了直接证据。The structures of lipids determine their biological functions,and the identification of C C double bond isomers in unsaturated lipids faces challenges.The direct nitrogen-methyl(N-Me)aziridination reaction allows for the derivatization of unsaturated lipid double bonds,which can combine with tandem mass spectrometry(MS/MS)to enable the resolving for positions of unsaturated lipid double bonds.However,current studies about the mechanism of the N-Me aziridination reaction lack direct evidence of intermediate processes.Here,a nano-electrostatic-spray ionization-mass spectrometry(nESTASI-MS)device based on aθcapillary was used to separate the reactants through the channels on both sides of theθcapillary,allowing the solutions to be mixed and react on-line during the electrospray process.This on-line mixing greatly shortened the residence time of the two reactants,providing for the successful capture and identification of short-lived intermediates during the reaction process.The device was used to study the reaction process of aziridination of unsaturated phosphatidylcholine(PC).N-Methyl-O-(2,4-dinitrophenyl)hydroxylamine(N-Me-DPH)was used as the amination reagent,PC 36∶2 as a representative substrate,and Rh 2(esp)2 as a catalyst to study the reactions of these three substances in different mixing modes.The results showed that N-Me-DPH pre-mixed with Rh 2(esp)2 may deactivate the catalyst and the relevant intermediates and products could not be observed.In the other two mixing modes,the key rhodium-nitrene intermediate and the ternary biradical intermediate containing the first C—N bond during the reaction were successfully captured and characterized,as well as the product containing 1-methyl aziridine structure,which provided key evidence for the mechanistic study of the direct aziridination reaction of N-Me.Derivatization of N-Me aziridination could generate the 1-methyl aziridine structure at the double bond position,which was susceptible to break during mass spectrometric collision-induced dissociation(CID)t

关 键 词：质谱(MS) 化学反应中间体 氮杂环丙烷化反应 双键位置鉴定 

分 类 号：O657.63[理学—分析化学]