化物重组导致白氨酸和单氨酸的分解途径不同
Ruihan Zheng1, Xubo Lai1, Jinmei Tan1
1School of Chemistry & Chemical Engineering, Nanchang University, Nanchang 330031, China. JLCHEN5858@163.com.
碰撞诱导解离 (CID) 显示了氨酸 (Leu) 和异氨酸 (Ile) 氨基酸的明显气相碎片化模式. 化物重新排列与β消除的差异解释了m/z69离子在质谱中的不同丰度.
科学领域:
- 分析化学 分析化学
- 物理化学 物理化学
- 生物化学 生化学
背景情况:
- 异构氨基酸,氨酸 (Leu) 和异构氨酸 (Ile) 的气相碎裂机制尚未完全理解.
- 使用质谱测量来区分Leu和Ile是具有挑战性的,因为它们的结构相似.
研究的目的:
- 使用碰撞诱导解离 (CID) 阐明质子Leu和Ile的气相碎片化机制.
- 为了解释它们的双重质谱中在m/z 69处观察到的特征性离子丰度的差异.
主要方法:
- 质子Leu和Ile的碰撞诱导解离 (CID).
- 密度函数理论 (DFT) 计算以确定碎片化能量.
- MS3实验,同位素标记和电喷射电离 (ESI) 在源 CID 进行验证.
主要成果:
- 在Leu和Ile CID双重质谱之间观察到m/z69离子丰度的显著差异.
- 对于Ile,1,2-化物转移比β消除更受青,产生了强烈的m/z69离子.
- 对于Leu,1,3-化物重新排列不如β消除,导致m/z 69离子几乎不存在.
结论:
- 竞争性化物重新排列和β消除途径决定了Leu和Ile之间观察到的碎片化差异.
- 这些发现为在质谱学中区分异构氨基酸提供了机制基础.
- 这种理解可以帮助更准确的序列和分析.
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