Structural Analysis of Lipid Hydroperoxides Using Mass Spectrometry with Alkali Metals
Structural Analysis of Lipid Hydroperoxides Using Mass Spectrometry with Alkali Metals
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DOI：
10.1021/jasms.1c00039
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发表时间：
2021-08-12
影响因子：
3.2
通讯作者：
Nakagawa, Kiyotaka
中科院分区：
文献类型：
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作者：
Kato, Shunji;Shimizu, Naoki;Nakagawa, Kiyotaka
脂质氧化涉及多种生物现象（例如氧脂素生成和氧化应激）。在氧化脂质结构中，脂质氢过氧化物 (LOOH) 的氢过氧基位置是决定其生物学作用的关键因素。尽管有这样的兴趣，目前确定氢过氧基位置的方法仍然存在一些缺点，例如选择性。虽然我们之前报道过使用 Na+ 来高度选择性测定氢过氧基位置的质谱方法，但除了钠化 LOOH（主要是亚油酸盐）提供特定碎片离子这一事实之外，我们一无所知。因此，本研究旨在研究不同碱金属对 LOOH 碎片的影响，并假设其进一步应用于其他复杂 LOOH 的分析。通过对PC 16:0/18:2;OOH（磷脂酰胆碱）和FA 18:2;OOH（脂肪酸）的分析，我们发现碎裂途径和离子强度很大程度上取决于碱金属的结合位置和类型（即Li+，Hock碎裂；Na+和K+，α-裂解（Na+>K+）；Rb+和Cs+，无碎裂）。此外，我们证明该方法可用于测定酯化脂质（例如磷脂和胆固醇酯）以及多不饱和脂肪酸（PUFA）（包括 n-3、n-6 和 n-9 FA）的氢过氧基位置。我们预计本研究中描述的见解可为传统脂质氧化研究提供更多独特的见解。
Lipid oxidation is involved in various biological phenomena (e.g., oxylipin generation and oxidative stress). Of oxidized lipid structures, the hydroperoxyl group position of lipid hydroperoxides (LOOHs) is a critical factor in determining their biological roles. Despite such interest, current methods to determine hydroperoxyl group positions possess some drawbacks such as selectivity. While we previously reported mass spectrometric methods using Na+ for the highly selective determination of hydroperoxyl group positions, nothing was known except for the fact that sodiated LOOHs (mainly linoleate) provide specific fragment ions. Thus, this study was aimed to investigate the effects of different alkali metals on the fragmentation of LOOHs, assuming its further application to analysis of other complex LOOHs. From the analysis of PC 16:0/18:2;OOH (phosphatidylcholine) and FA 18:2;OOH (fatty acid), we found that fragmentation pathways and ion intensities largely depend on the binding position and type of alkali metals (i.e., Li+, Hock fragmentation; Na+ and K+, alpha-cleavage (Na+ > K+); Rb+ and Cs+, no fragmentation). Furthermore, we proved that this method can be applied to determine the hydroperoxyl group position of esterified lipids (e.g., phospholipids and cholesterol esters) as well as polyunsaturated fatty acids (PUFAs) including n-3, n-6, and n-9 FA. We anticipate that the insights described in this study provide additional unique insights to conventional lipid oxidation research.