Reaction of hydrogen peroxide with ferrylhemoglobin: Superoxide production and heme degradation
Reaction of hydrogen peroxide with ferrylhemoglobin: Superoxide production and heme degradation
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DOI：
10.1021/bi992170y
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发表时间：
2000-10-10
期刊：
影响因子：
2.9
通讯作者：
Rifkind, JM
中科院分区：
文献类型：
--
作者：
Nagababu, E;Rifkind, JM
铁(II)血红蛋白(Hb)而不是铁(III)血红蛋白(MetHb)与过氧化氢反应导致血红素部分降解。观察到与亚铁Hb反应的化合物(如硫化钠)和过氧化物酶底物(ABTS和o-dianisidine)抑制了血红素的降解，这表明亚铁Hb的形成是亚铁Hb降解所必需的。过氧化氢和高铁Hb的反应被证明是通过添加过氧化氢酶来抑制血红素的降解，即使在高铁Hb水平达到最高水平后，过氧化氢也会被清除。电子顺磁共振研究表明，过氧化氢与亚铁Hb反应生成血红素降解产物，包括过氧化氢的单电子氧化为氧自由基超氧化物。硫化钠抑制了超氧化物的产生和血红素荧光降解产物的形成，将超氧化物的产生与血红素的降解联系在一起。无法通过MetHb与过氧化氢反应产生血红素降解产物的原因是，过氧化氢与氧铁Hb反应经历了两个电子的氧化，产生氧气而不是超氧化物。该反应不会产生血红素降解，但负责催化清除过氧化氢。在还原的血红蛋白与过氧化氢的反应中，由于中间产物metHb的形成，过氧化氢的迅速消耗被证明限制了血红素的降解程度。
The reaction of Fe(II) hemoglobin (Hb) but not Fe(III) hemoglobin (metHb) with hydrogen peroxide results in degradation of the heme moiety. The observation that heme degradation was inhibited by compounds, which react with ferrylHb such as sodium sulfide, and peroxidase substrates (ABTS and o-dianisidine), demonstrates that ferrylHb formation is required for heme degradation. A reaction involving hydrogen peroxide and ferrylHb was demonstrated by the finding that heme degradation was inihibited by the addition of catalase which removed hydrogen peroxide even after the maximal level of ferrylHb was reached. The reaction of hydrogen peroxide with ferrylHb to produce heme degradation products was shown by electron paramagnetic resonance to involve the one-electron oxidation of hydrogen peroxide to the oxygen free radical, superoxide. The inhibition by sodium sulfide of both superoxide production and the formation of fluorescent heme degradation products links superoxide production with heme degradation. The inability to produce heme degradation products by the reaction of metHb with hydrogen peroxide was explained by the fact that hydrogen peroxide reacting with oxoferrylHb undergoes a two-electron oxidation, producing oxygen instead of superoxide. This reaction does not produce heme degradation, but is responsible for the catalytic removal of hydrogen peroxide. The rapid consumption of hydrogen peroxide as a result of the metHb formed as an intermediate during the reaction of reduced hemoglobin with hydrogen peroxide was shown to limit the extent of heme degradation.