Identification of Abundant Alkyl Ether Glycerophospholipids in the Human Lens by Tandem Mass Spectrometry Techniques
Identification of Abundant Alkyl Ether Glycerophospholipids in the Human Lens by Tandem Mass Spectrometry Techniques
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DOI：
10.1021/ac802395d
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发表时间：
2009-03-01
影响因子：
7.4
通讯作者：
Blanksby, Stephen J.
中科院分区：
文献类型：
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作者：
Deeley, Jane M.;Thomas, Michael C.;Blanksby, Stephen J.
先前的研究表明，人的透镜含有醚键的甘油磷脂。这些脂质与常规甘油磷脂的不同之处在于sn-1取代基通过1-O-烷基或1-O-烷-1 '-烯基醚而不是酯键连接到甘油主链上。本研究采用了碰撞诱导解离（CID）和臭氧诱导解离（OzID）的组合，以明确区分这种1-O-烷基和1-O-烷基-1 '-烯基醚。使用这些方法，发现人透镜含有几种丰富的1-O-烷基甘油磷酸-乙醇胺，包括GPEtn（16：0 e/9 Z-18：1）、GPEtn（11 Z-18：1 e/9 Z-18：1）和GPEtn（18：0 e/9 Z-18：1），以及一系列相关的不常见的1-O-烷基甘油磷酸丝氨酸，包括GPSer（16：0 e/9 Z-18：1）、GPSer（11 Z-18：1 e/9 Z-18：1）、GPSer（18：0 e/9 Z-18：1），据我们所知，这些物质以前在人体组织中未观察到。异构体1-O-烷-1 '-烯基醚不存在或丰度低。使用OzID检查磷脂内的双键位置，发现存在几种位置异构体，包括n-9、n-7甚至n-5位置处的不饱和位点。串联CID/OzID实验揭示了1-O-醚连接链的n-7位双键的偏好，而n-9双键在酯连接的脂肪酸中占主导地位[例如，GPEtn（11Z-18：1e/9Z-18：1）和GPSer（11Z-18：1e/9Z-18：1）]。这些双键位置异构体在链中的sn-1和sn-2位置的不同组合指向人类透镜内醚-脂质的显著分子多样性。
Previous studies have shown that the human lens contains glycerophospholipids with ether linkages. These lipids differ from conventional glycerophospholipids in that the sn-1 substituent is attached to the glycerol backbone via an 1-O-alkyl or an 1-O-alk-1'-enyl ether rather than an ester bond. The present investigation employed a combination of collision-induced dissociation (CID) and ozone-induced dissociation (OzID) to unambiguously distinguish such 1-O-alkyl and 1-O-alk-1'-enyl ethers. Using these methodologies the human lens was found to contain several abundant 1-O-alkyl glycerophos-phoethanolamines, including GPEtn(16:0e/9Z-18:1), GPEtn(11Z-18:1e/9Z-18:1), and GPEtn(18:0e/9Z-18:1), as well as a related series of unusual 1-O-alkyl glycerophosphoserines, including GPSer(16:0e/9Z-18:1), GPSer(11Z-18:1e/9Z-18:1), GPSer(18:0e/9Z-18:1) that to our knowledge have not previously been observed in human tissue. Isomeric 1-O-alk-1'-enyl ethers were absent or in low abundance. Examination of the double bond position within the phospholipids using OzID revealed that several positional isomers were present, including sites of unsaturation at the n-9, n-7, and even n-5 positions. Tandem CID/OzID experiments revealed a preference for double bonds in the n-7 position of 1-O-ether linked chains, while n-9 double bonds predominated in the ester-linked fatty acids [e.g., GPEtn(11Z-18:1e/9Z-18:1) and GPSer(11Z-18:1e/9Z-18:1)]. Different combinations of these double bond positional isomers within chains at the sn-1 and sn-2 positions point to a remarkable molecular diversity of ether-lipids within the human lens.