HUMAN NEUTROPHILS EMPLOY MYELOPEROXIDASE H2O2 CL SYS TO OXIDIZE

人类中性粒细胞利用髓过氧化物酶 H2O2 CL 系统进行氧化

• 批准号: 6486705
• 负责人: STANLEY HAZEN
• 金额: $ 15.75万
• 依托单位: WASHINGTON UNIVERSITY
• 依托单位国家: 美国
• 财政年份: 2001
• 资助国家: 美国
• 起止时间: 2001-08-01 至 2002-07-31
• 项目状态: 已结题
• 来源: https://reporter.nih.gov/project-details/6486705
• 关键词: biomedical resource; cardiovascular system; enzymes; human tissue; minerals; proteins; spectrometry

In the accompanying manuscript we demonstrate that neutrophils oxidize nearly all of the amino acids commonly found in plasma to a corresponding family of aldehydes in high yield. The reaction is mediated by hypochlorous acid (HOCl), the major oxidant generated by the myeloperoxidase-H2O2-Cl- system of phagocytes. We now present evidence for the underlying mechanism of this reaction, including the structural requirements and reaction intermediates formed. Utilizing mass spectrometry and isotopically labeled amino acids we rule out hydrogen atom abstraction from the (-carbon as the initial event in aldehyde formation during amino acid oxidation, a pathway known to occur with ionizing radiation. Aldehyde generation from amino acids required the presence of an (-amino moiety; (- and (-amino acids did not form aldehydes upon oxidation by either the myeloperoxidase system or HOCl, generating stable monochloramines instead. UV difference spectroscopy, HPLC and multin uclear (1H , 15N) NMR spectroscopy established that the conversion of (-amino acids into aldehydes begins with generation of an unstable (-monochloramine, which subsequently decomposes to yield an aldehyde. Precursor-product relationships between (-amino acid and (-monochloramine, and (-monochloramine and aldehyde were confirmed by HPLC purification of the reaction intermediate and subsequent 1H and 15N NMR spectroscopy. Collectively, these results detail the chemical mechanism and reaction intermediates generated during conversion of amino acids into aldehydes by myeloperoxidase-generated HOCl.

在随附的手稿中，我们证明中性粒细胞 将血浆中常见的几乎所有氨基酸氧化成 相应的醛族，收率高。 反应是 由次氯酸（HOCl）介导，次氯酸是由次氯酸产生的主要氧化剂 吞噬细胞的髓过氧化物酶-H2O2-Cl-系统。 我们现在呈现 该反应的基本机制的证据，包括 结构要求和形成的反应中间体。 利用 我们排除了质谱法和同位素标记的氨基酸 从(-碳中提取氢原子作为初始事件 氨基酸氧化过程中醛的形成，这是已知的途径 与电离辐射一起发生。 由氨基酸生成醛 需要存在(-氨基部分；(-和(-氨基酸) 被髓过氧化物酶系统氧化后不会形成醛 或 HOCl，生成稳定的一氯胺。 紫外线差异 光谱、HPLC 和多核 (1H, 15N) NMR 光谱 确定 (-氨基酸开始转化为醛) 生成不稳定的（-一氯胺，随后 分解产生醛。 前体-产物关系 (-氨基酸和(-一氯胺)之间，以及(-一氯胺和 通过HPLC纯化反应物确认醛 中间体和随后的 1H 和 15N NMR 光谱。 总的来说，这些结果详细说明了化学机理和反应 氨基酸转化过程中产生的中间体 髓过氧化物酶产生的 HOCl 产生醛类。