MASS SPECTROMETRIC QUANTIFICATION OF 3 CHLOROTYROSINE IN HUMAN TISSUES

蛋白质的氧化修饰涉及到一种 从动脉粥样硬化到衰老的各种过程。 确定潜在的氧化途径已被证明是困难的， 然而，由于缺乏不同氧化的特异性标志物， 途径。 先前的体外研究表明， 3-氯酪氨酸是髓过氧化物酶催化的特异性产物， 氧化损伤，氯化氨基酸因此可以作为 体内吞噬细胞介导的组织损伤的指数。 这里我们 描述了一种高灵敏度和特异性的分析方法， 定量组织的3-氯酪氨酸含量。 测定 将气相色谱与稳定同位素稀释质量相结合 光谱法，它检测阿托摩尔水平的3-氯酪氨酸在一个 单一决心 此外，该方法是高度可重复的， 样本间和样本内变异系数<3%。 的 3-氯酪氨酸E特异性、灵敏度和重复性 测定应该使这种方法用于探索作用 的 髓过氧化物酶在体内催化氧化反应。

Oxidative modification of proteins has been implicated in a variety of processes ranging from atherosclerosis to aging. Identifying the underlying oxidation pathways has proven difficult, however, due to the lack of specific markers for distinct oxidation pathways. Previous in vitro studies demonstrated that 3-chlorotyrosine is a specific product of myeloperoxidase-catalyzed oxidative damage and that the chlorinated amino acid may thus serve as an index of phagocyte-mediated tissue injury in vivo. Here we describe a highly sensitive and specific analytical method for the quantification of 3-chlorotyrosine content of tissues. The assay combines gas chromatography with stable isotope dilution mass spectrometry, and it detects attomole levels of 3-chlrotyrosine in a single determination. Furthermore, the method is highly reproducible, with inter- and intra-sample coefficients of variance of <3%. The specificity, sensitivity, and reproducibility of 3-chlorotyrosin e determin ation should make this method useful for exploring the role of myeloperoxidase in catalyzing oxidative reactions in vivo.