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Rapid Commun Mass Spectrom. 2010 Mar;24(6):768-72. doi: 10.1002/rcm.4447.
Analysis of protein oxidation is necessary in numerous areas of biochemistry, including hydroxyl radical surface mapping, oxidative stress assays, and pharmaceutical stability testing. Mass spectrometry is one of the tools most often used to identify protein oxidation products, and previous studies have attempted to identify and characterize all of the major oxidation products detected by mass spectrometry for each amino acid residue. In this note, we present evidence that in heavily oxidized protein samples, such as those produced by hydroxyl radical surface mapping, a major oxidation product of methionine is homocysteic acid. The formation of homocysteic acid from methionine was previously unrecognized in other mass spectrometric analyses, and has important implications for the analysis of oxidized samples, as well as potential implications as to the functional consequences of methionine oxidation.
蛋白质氧化分析在生物化学的众多领域都是必要的，包括羟自由基表面作图、氧化应激测定和药物稳定性测试。质谱分析是最常用于鉴定蛋白质氧化产物的工具之一，之前的研究曾试图鉴定和描述每种氨基酸残基经质谱检测到的所有主要氧化产物。在本说明中，我们提供的证据表明，在高度氧化的蛋白质样品中，例如由羟自由基表面作图产生的那些样品中，蛋氨酸的一个主要氧化产物是同型半胱氨酸酸。同型半胱氨酸酸由蛋氨酸形成在之前的其他质谱分析中未被识别，这对氧化样品的分析有重要意义，也可能对蛋氨酸氧化的功能后果有影响。
