Departamento de Bioquímica, Facultad de Medicina, Universidad de la República, 11800 Montevideo, Uruguay.
Centro de Investigaciones Biomédicas (CEINBIO), Facultad de Medicina, Universidad de la República, Montevideo, Uruguay.
J Biol Chem. 2020 May 8;295(19):6665-6676. doi: 10.1074/jbc.RA120.013402. Epub 2020 Mar 26.
Reactive oxygen and nitrogen species have been implicated in many biological processes and diseases, including immune responses, cardiovascular dysfunction, neurodegeneration, and cancer. These chemical species are short-lived in biological settings, and detecting them in these conditions and diseases requires the use of molecular probes that form stable, easily detectable, products. The chemical mechanisms and limitations of many of the currently used probes are not well-understood, hampering their effective applications. Boronates have emerged as a class of probes for the detection of nucleophilic two-electron oxidants. Here, we report the results of an oxygen-18-labeling MS study to identify the origin of oxygen atoms in the oxidation products of phenylboronate targeted to mitochondria. We demonstrate that boronate oxidation by hydrogen peroxide, peroxymonocarbonate, hypochlorite, or peroxynitrite involves the incorporation of oxygen atoms from these oxidants. We therefore conclude that boronates can be used as probes to track isotopically labeled oxidants. This suggests that the detection of specific products formed from these redox probes could enable precise identification of oxidants formed in biological systems. We discuss the implications of these results for understanding the mechanism of conversion of the boronate-based redox probes to oxidant-specific products.
活性氧和氮物种参与了许多生物学过程和疾病，包括免疫反应、心血管功能障碍、神经退行性变和癌症。这些化学物质在生物环境中寿命短暂，因此需要使用形成稳定、易于检测产物的分子探针来检测这些条件和疾病。目前使用的许多探针的化学机制和局限性尚未得到很好的理解，这阻碍了它们的有效应用。硼酸酯已成为一类用于检测亲核两电子氧化剂的探针。在这里，我们报告了氧-18 标记 MS 研究的结果，以确定靶向线粒体的苯硼酸酯氧化产物中氧原子的来源。我们证明，过氧化氢、过氧单碳酸盐、次氯酸盐或过氧亚硝酸盐氧化硼酸酯涉及这些氧化剂中氧原子的掺入。因此，我们得出结论，硼酸酯可用作追踪同位素标记氧化剂的探针。这表明，这些氧化还原探针形成的特定产物的检测可以实现对生物系统中形成的氧化剂的精确识别。我们讨论了这些结果对理解基于硼酸酯的氧化还原探针转化为氧化剂特异性产物的机制的影响。
