Electrospray ionization ion trap multiple-stage mass spectrometric fragmentation pathways of leucine and isoleucine: an ab initio computational study.
Electrospray ionization ion trap multiple-stage mass spectrometric fragmentation pathways of leucine and isoleucine: an ab initio computational study.
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DOI：
10.1002/rcm.3198
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发表时间：
2007-10
期刊：
影响因子：
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通讯作者：
A. Armirotti;Carlo Scapolla;U. Benatti;G. Damonte
中科院分区：
文献类型：
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作者：
A. Armirotti;Carlo Scapolla;U. Benatti;G. Damonte
我们最近证明了通过连续串联质量步骤区分几种胰蛋白酶肽中的亮氨酸和异亮氨酸的可能性（Armirotti 等人 J. Am. Soc. Mass Spectrom. 2007; 18: 57），利用 Ile 的铵离子的气相重排。在本文中，我们探讨了两种氨基酸的串联质谱行为。我们提出了 Ile 诊断性 m/z 69 离子的合理结构，该结构于 1996 年首次报道（Hulst 和 Kientz J. Mass. Spectrom. 1996；31：1188），并解释了为什么它的形成相对于 Leu 更有利。我们的结论得到了从头算量子化学计算和同位素标记标准实验的支持。
We recently demonstrated the possibility to distinguish between leucine and isoleucine in several tryptic peptides by means of consecutive tandem mass steps (Armirotti et al. J. Am. Soc. Mass Spectrom. 2007; 18: 57), exploiting a gas-phase rearrangement of the immonium ion of Ile. In the present paper we explore the tandem mass spectrometric behaviour of the two amino acids. We propose a plausible structure for the diagnostic m/z 69 ion of Ile, that was reported for the first time in 1996 (Hulst and Kientz J. Mass. Spectrom. 1996; 31: 1188), and we explain why its formation is favoured with respect to Leu. Our conclusions are supported by ab initio quantum chemistry calcultations and isotope-labelled standards experiments.