Multiple Hydrogen Loss from [M + H]+ and [a]+ ions of Peptides in MALDI In-Source Decay Using a Dinitro-Substituted Matrix
Multiple Hydrogen Loss from [M + H]+ and [a]+ ions of Peptides in MALDI In-Source Decay Using a Dinitro-Substituted Matrix
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DOI：
10.1021/jasms.9b00013
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发表时间：
2020-03-01
影响因子：
3.2
通讯作者：
Takayama, Mitsuo
中科院分区：
文献类型：
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作者：
Miyazawa, Kei;Takayama, Mitsuo
用MALDI-ISD和二硝基取代基质研究了多个氢提取肽阳离子[M + H + mH]中心点（+）的形成和自由基定向解离。以3,5-二硝基水杨酸（3,5- dnsa）和3,4-二硝基苯甲酸（3,4- dnba）为基质的合成肽的MALDI-ISD导致从分析物[M + H]+和片段[a]+离子中提取多个氢，即[M + H - mH]（+）和[a - nH](+) （M =1-8）。当使用没有Phe/Tyr/ His/Cys残基的肽时，所有的ISD光谱都显示出异常强烈的[a]（+）离子，这些离子来自于Leu-Xxx残基的C α - C键的裂解。3,5- ddna和3,4- dnba生成的[a(n)]（+）系列离子的强度随着残基数n的增加而迅速下降，表明[M + H mH]中心点（+）的多自由基位点发生了劈裂。结果表明，质子化肽[M + H]（+）的多次抽氢主要发生在主链酰胺氮上。
The formation and radical-directed dissociation of multiple hydrogen-abstracted peptide cations [M + H mH]center dot(+) has been reported using MALDI-ISD with dinitro-substituted matrices. The MALDI-ISD of synthetic peptides using 3,5-dinitrosalicylic acid (3,5-DNSA) and 3,4-dinitrobenzoic acid (3,4-DNBA) as matrices resulted in multiple hydrogen abstraction from the analyte [M + H]+ and fragment [a]+ ions, i.e., [M + H - mH](+) and [a - nH](+) (m =1-8). All of the ISD spectra showed unusually intense [a](+) ions originating from cleavage at the C alpha - C bond of the Leu-Xxx residues when peptides without Phe/Tyr/ His/Cys residues were used. The intensity of the [a(n)](+) series ions generated using 3,5-DNSA and 3,4-DNBA rapidly decreased with increasing residue number n, suggesting cleavage at multiradical sites of [M + H mH]center dot(+). It was suggested that multiple hydrogen abstraction from protonated peptides [M + H ](+) mainly takes place place from the backbone amide nitrogen.