化合物特异性和分子内 δ15N 多氨基酸的分析:西斯蒂丁
Charlotte Wing Man Lee1, Mark A Altabet2, Jesus Baca1
1Texas A&M University Corpus Christi, Corpus Christi, Texas 78412, United States.
Analytical chemistry
|July 24, 2025
概括
这项研究引入了一种新的方法,用于测量必不可少的氨基酸histidine (HIS) 中的同位素. 这些发现揭示了histidine的α-和侧链之间的明显的同位素值,为氨基酸代谢提供了洞察力.
科学领域:
- 生物地质化学生物地质化学
- 分析化学 分析化学
- 生物化学 生化学
背景情况:
- 胺 (HIS) 是一种必需的氨基酸,对于金属化和质子缓冲等生物过程至关重要.
- 它独特的结合和代谢途径表明分子内 (N) 同位素值可以揭示代谢信息.
- 目前的分析方法缺乏在天然胺样本中进行分子内同位素分析的精度.
研究的目的:
- 开发一种新的分析方法,用于确定特定化合物,15 (δ15N) 值.
- 将这种方法应用于商业胺和生物样本,以研究流路径.
- 建立分析其他多氨基酸 (如谷氨酸) 的基础.
主要方法:
- 开发了一个新的分析方案,使用离子交换色谱 (IC) 来分离histidine.
- 分析了两个分数:一个完全氧化了总N同位素值 (δ15N HIS-Total),另一个使用选择性NaClO氧化对α-N和侧链-N (δ15N HIS-α,δ15N HIS-s).
- 分子内 δ15N 值是根据选择性氧化分量的同位素组成计算的.
主要成果:
- 这种新方法成功确定了histidine的分子内d15N值.
- 与侧链N相比,α-N在15N中得到了持续的丰富 (Δδ15Nα-s ≈ +8‰在商业HIS中, +3到 +25‰在生物样本中).
- 这种观察到的分化很可能归因于α-N的偏好的去胺和代谢.
结论:
- 开发的分析方法使得histidine的精确分子内同位素分析成为可能.
- 希斯蒂丁的分子内 δ15N 值为不同的 N 代谢途径提供了宝贵的见解.
- 这种方法可以扩展到研究其他多氨基酸中的同位素变异.
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