8-nitro-2′-deoxyguanosine, a specific marker of oxidation by reactive nitrogen species, is generated by the myeloperoxidase hydrogen peroxide nitrite system of activated human phagocytes
8-nitro-2′-deoxyguanosine, a specific marker of oxidation by reactive nitrogen species, is generated by the myeloperoxidase hydrogen peroxide nitrite system of activated human phagocytes
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DOI：
10.1021/bi9822980
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发表时间：
1999-02-23
期刊：
影响因子：
2.9
通讯作者：
Heinecke, JW
中科院分区：
文献类型：
--
作者：
Byun, J;Henderson, JP;Heinecke, JW
吞噬细胞产生的活性中间产物会损害DNA，并可能导致慢性炎症和癌症之间的联系。髓过氧化物酶是一种由激活的吞噬细胞分泌的血红素蛋白，是此类反应的潜在催化剂。最近的研究表明，该酶利用过氧化氢(H_2O_2)和亚硝酸盐(NO_2-)生成活性氮物种，将酪氨酸转化为3-硝基酪氨酸。我们现在报道，激活的人中性粒细胞使用髓过氧化物酶、H_2O_2和NO2-来生成DNA的核苷之一--硝酸盐2‘-脱氧鸟苷。通过高效液相色谱、UV/Vis光谱和质谱分析，确定了该反应的两个主要产物为8-硝基-2‘-脱氧鸟苷和8-硝基-2’-脱氧鸟苷。硝化作用需要完整的酶系统中的每一种成分，并被过氧化氢酶和血红素毒药抑制。但它不受氯离子影响，几乎不受次氯酸清除剂的影响，表明该反应剂是髓过氧化物酶对NO2-进行单电子氧化的产物，是类二氧化氮物种。或者，2‘-脱氧鸟苷可以直接被酶氧化产生自由基物种，然后与亚硝酸根或亚硝酸根反应。以生成观察到的产品。用佛波酯刺激的人中性粒细胞也产生8-硝基-2‘-脱氧鸟苷。该反应需要NO2-，并被过氧化氢酶和血红素毒素抑制，暗示髓过氧化物酶参与了细胞介导的途径。这些结果表明，人类中性粒细胞利用髓过氧化物酶-H_2O_2-NO_2-体系产生的活性物质可以硝化到2‘-脱氧鸟苷的C-8位。我们的观察增加了髓过氧化物酶和其他过氧化物酶产生的活性氮物种导致核碱基氧化和炎症部位组织损伤的可能性。
Reactive intermediates generated by phagocytes damage DNA and may contribute to the link between chronic inflammation and cancer. Myeloperoxidase, a heme protein secreted by activated phagocytes, is a potential catalyst for such reactions. Recent studies demonstrate that this enzyme uses hydrogen peroxide (H2O2) and nitrite (NO2-) to generate reactive nitrogen species which convert tyrosine to 3-nitrotyrosine. We now report that activated human neutrophils use myeloperoxidase, H2O2, and NO2- to nitrate 2'-deoxygoanosine, one of the nucleosides of DNA. Through HPLC, UV/vis spectroscopy, and mass spectrometry, the two major products of this reaction were identified as 8-nitroguanine and 8-nitro-2'-deoxyguanosine. Nitration required each component of the complete enzymatic system and was inhibited by catalase and heme poisons. However, it was independent of chloride ion and little affected by scavengers of hypochlorous acid, suggesting that the reactive agent is a nitrogen dioxide-like species that results from the one-electron oxidation of NO2- by myeloperoxidase. Alternatively, 2'-deoxyguanosine might be oxidized directly by the enzyme to yield a radical species which subsequently reacts with NO2- or NO2. to generate the observed products. Human neutrophils stimulated with phorbol ester also generated 8-nitroguanine and 8-nitro-2'-deoxyguanosine. The reaction required NO2- and was inhibited by catalase and heme poisons, implicating myeloperoxidase in the cell-mediated pathway. These results indicate that human neutrophils use the myeloperoxidase-H2O2-NO2- system to generate reactive species that can nitrate the C-8 position of 2'-deoxyguanosine. Our observations raise the possibility that reactive nitrogen species generated by myeloperoxidase and other peroxidases contribute to nucleobase oxidation and tissue injury at sites of inflammation.