Characterization of novel myelin components 3-O-acetyl-sphingosine galactosylceramides by electrospray ionization Q-TOF MS and MS/CID-MS of Li+ adducts.
Characterization of novel myelin components 3-O-acetyl-sphingosine galactosylceramides by electrospray ionization Q-TOF MS and MS/CID-MS of Li+ adducts.
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通过 Li 加合物的电喷雾电离 Q-TOF MS 和 MS/CID-MS 表征新型髓磷脂成分 3-O-乙酰基-鞘氨醇半乳糖神经酰胺。
DOI：
10.1002/jms.1190
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发表时间：
2007
期刊：
影响因子：
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通讯作者：
Levery,StevenB
中科院分区：
文献类型：
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作者：
Bennion,Beau;Dasgupta,Somsankar;Hogan,EdwardL;Levery,StevenB
正常时相HPTLC中Rf值高于单糖神经酰胺(MGCS)的神经鞘糖脂似乎是髓鞘的正常成分。已从大鼠脑中分离出一系列这样的低极性成分，称为快速移动脑苷脂(FMC)，其中两个组分(FMC-1和FMC-2)被发现是半乳糖神经酰胺(GalCer)的新衍生物，在狮身人面像的3-羟基上表现出O-乙酰化，并包括非羟基或2-羟基脂肪-N-酰化(Dasgupta S，Leach SB，Hogan EL.J.Liped Res.2002；43：751-761)。与母体化合物相似，3-O-乙酰-狮身人面像衍生物在脂肪-N-酰基链长方面表现出相当大的差异，表现为非均相分子离子(Li+加合物)谱。然而，没有对单个分子变异体(‘脂形式’)进行详细分析，例如通过串联MS/CID-MS分析。此外，分离出了其他几个具有更低极性(HPTLCRf值较高)的FMC，但仍未确定其特征。在本研究中，利用Q-TOF质谱仪上Li+加合物的阳离子ESI-MS和MS/CID-MS对已知和未知的FMC组分进行了分析。由于Q-TOF仪尚未应用于石脑苷类和FMCS的MS分析，我们系统地获得了牛脑GalCer(两种类型)和已鉴定的大鼠脑FMCS(FMC-1和FMC-2)的MS/CID-MS谱，并比较了它们的裂解行为。随后对以前未确定的FMC组分(FMC-3至FMC-5/6/7)进行了系统分析。GalCer和FMC组分可以用这种技术进行分析，数据证实后者都是相关的3-O-乙酰-狮身人面像衍生物，较高的Rf组分在半乳糖残基上进行了加成的O-乙酰基修饰，进一步降低了它们的极性。描述了该技术的实用性、未知FMCS的结构及其特征碎片模式。版权所有©2007 John Wiley&Sons，Ltd.
Glycosphingolipids withRfvalues higher than those of monoglycosylceramides (MGCs) in normal phase HPTLC appear to be normal components of myelin. A series of such low polarity components, referred to as ‘fast moving cerebrosides’ (FMCs), have been isolated from rat brain, and two of these fractions (FMC‐1 and FMC‐2) were found to be novel derivatives of galactosylceramide (GalCer) exhibitingO‐acetylation at the 3‐hydroxy group of the sphingoid moiety, and incorporating either non‐hydroxy or 2‐hydroxy fatty‐N‐acylation (Dasgupta S, Levery SB, Hogan EL.J. Lipid Res.2002; 43: 751–761). Similar to the parent compounds, the 3‐O‐acetyl‐sphingoid derivatives exhibit considerable diversity with respect to fatty‐N‐acyl chain length, manifested by heterogeneous molecular ion (Li+adduct) profiles. However, a detailed analysis of the individual molecular variants (‘lipoforms’), e.g. by tandem MS/CID‐MS analysis, was not carried out. In addition, several other FMCs distinguished by even lower polarity (higher HPTLCRfvalues) were isolated but have remained uncharacterized. For this study, analysis of both the known and unknown FMC components was carried out by positive ion ESI‐MS and MS/CID‐MS of their Li+adducts on a Q‐TOF mass spectrometer. Since a Q‐TOF instrument has not yet been applied to MS of lithiated cerebrosides and FMCs, MS/CID‐MS spectra of bovine brain GalCer (both types) and the previously characterized rat brain FMCs (FMC‐1 and FMC‐2), having 3‐O‐acetylation of the sphingoid, were systematically acquired and their fragmentation behavior compared. This was followed by systematic analysis of previously uncharacterized FMC fractions (FMC‐3 through FMC‐5/6/7). The GalCer and FMC components proved to be amenable to analysis by this technique, and the data confirm that the latter are all related 3‐O‐acetyl‐sphingoid derivatives, with the higherRfcomponents carrying additionalO‐acetyl modifications on the galactosyl residue, which further reduce their polarity. The utility of the technique, the structures of unknown FMCs, and their characteristic fragmentation patterns are described. Copyright © 2007 John Wiley & Sons, Ltd.