STRUCTURAL CHARAC OF TRIACYLGLYCEROLS AS LITHIATED ADDUCTS

三酰基甘油作为锂加合物的结构特征

• 批准号: 6665788
• 负责人: FONG-FU HSU
• 金额: $ 15.75万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2002
• 资助国家: 美国
• 起止时间: 2002-08-01 至 2003-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6665788
• 关键词: biological products; biomedical resource; cardiovascular system; gas; hematology; immunology; infection; inflammation; proteins; spectrometry; technology /technique

We describe features of tandem mass spectra of lithiated adducts of triacylglycerol species obtained by electrospray ionization mass spectrometry with low energy collisionally activated dissociation (CAD) on a triple stage quadrupole instrument. The spectra distinguish isomeric triacylglycerol species and permit assignment of the mass of each fatty acid substituent and positions on the glycerol backbone to which substituents are esterified. Source CAD-MS2 experiments permit assignment of double bond locations in polyunsaturated fatty acid substituents. The ESI/MS/MS spectra contain [M+Li-(RnCO2H)]+, [M+Li-(RnCO2Li)]+, and RnCO+ ions, among others, that permit assignment of the masses of fatty acid substituents. Relative abundances of these ions reflect positions on the glycerol backbone to which substituents are esterified. The tandem spectra also contain ions reflecting combined elimination of two adjacent fatty acid residues, one of which is eliminated as a free f att y acid and the other as an a,b-unsaturated fatty acid. Such combined losses always involve the sn-2 substituent, and this feature provides a robust means to identify that substituent. Fragment ions reflecting combined losses of both sn-1 and sn-3 substituents without loss of the sn-2 substituent are not observed. Schemes are proposed to rationalize formation of major fragment ions in tandem mass spectra of lithiated TAG that are supported by studies with deuterium-labeled TAG and by source CAD-MS2 experiments. These schemes involve initial elimination of a free fatty acid in concert with a hydrogen atom abstracted from the a-methylene group of an adjacent fatty acid, followed by formation of a cyclic intermediate that decomposes to yield other characteristic fragment ions. Determination of double bond location in polyunsaturated fatty acid substituents of TAG is achieved by source CAD experiments in which dilithiated adducts of fatty acid substituents are produced in the ion source and subjected to CAD in the collision cell. Product ions are analyzed in the final quadrupole to yield information on double bond location.

我们描述了岩性加合物的串联质谱的特征 通过电喷雾电离质量获得的三酰基甘油物种 低能量碰撞激活解离的光谱法 （CAD）在三级四极杆仪器上。 光谱 区分异构三酰基甘油物种，并允许分配 每个脂肪酸取代基的质量和甘油的位置 取代基酯酯化的骨干。 来源CAD-MS2 实验允许分配双键位置 多不饱和脂肪酸取代基。 ESI/MS/MS光谱 包含[m+li-（rnco2H）]+，[m+li-（rnco2li）]+和rnco+ions， 其他，允许分配脂肪酸的质量 取代基。 这些离子的相对丰度反映了对 取代基酯化的甘油主链。 这 串联光谱还包含反映综合消除的离子 两个相邻的脂肪酸残基，其中一个被消除为自由 f at y酸，另一种是a的a，b-不饱和脂肪酸。 这样的 结合损失始终涉及SN-2取代基，此功能 提供强大的手段来识别该取代基。 碎片离子 反映没有SN-1和SN-3取代基的组合损失 未观察到SN-2取代基的损失。 提出了方案 合理化串联质谱中主要碎片离子的形成 由氘标记的研究支持的岩性标签 标签和源CAD-MS2实验。 这些方案涉及初始 与氢原子共同消除游离脂肪酸 从相邻脂肪酸的A-甲基烯基团中抽象 然后形成分解为的环状中间体 产生其他特征片段离子。 确定双重 TAG的多不饱和脂肪酸取代基的键位置为 通过源CAD实验实现，在该实验中伸出的加合物 脂肪酸取代基是在离子源中产生的，并且 在碰撞电池中进行CAD。 产品离子在 最终四极杆，以产生有关双键位置的信息。