Oxidation of hemoglobin and the enhancement produced by nitroblue tetrazolium.
Oxidation of hemoglobin and the enhancement produced by nitroblue tetrazolium.
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发表时间：
1994-10
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通讯作者：
O. Abugo;J. Rifkind
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作者：
O. Abugo;J. Rifkind
本文研究了血红蛋白的自氧化与氧分压的关系及加入氮蓝四唑的影响。结果表明，在中等氧压下的增强的自氧化作用只能部分地由氧与脱氧链的外层反应来解释。与部分氧合血红蛋白的性质相关的额外增强已归因于血红素的远端侧上的流动性，其促进通过远端组氨酸的结合氧的亲核置换。氮蓝四唑，除了与自氧化过程中形成的超氧化物反应，被证明直接氧化脱氧和氧合血红蛋白在两个步骤中，通过一个电子还原中间体，四唑啉自由基进行。尽管含氧链被氮蓝四唑氧化，但在高氧压下观察到氮蓝四唑的总体还原少得多。这一现象归因于四唑啉基自由基和甲瓒两者被氧再氧化。还发现与氮蓝四唑的反应有助于在中等氧压下增强氧化。这种行为可以通过与硝蓝四氮唑的双电子反应以及硝蓝四氮唑反应中涉及的各种过程对氧的依赖性来解释。
The autoxidation of hemoglobin as a function of oxygen pressure and the effect of added nitroblue tetrazolium have been studied. It has been shown that the enhanced autoxidation at intermediate oxygen pressures can only be partially explained by the outer-sphere reaction of oxygen with deoxygenated chains. An additional enhancement associated with the properties of partially oxygenated hemoglobins has been attributed to the mobility on the distal side of the heme which facilitates the nucleophilic displacement of bound oxygen by the distal histidine. Nitroblue tetrazolium, in addition to reacting with the superoxide formed during autoxidation, is shown to oxidize directly both deoxygenated and oxygenated hemoglobin in two steps, proceeding through the one-electron reduced intermediate, a tetrazolinyl radical. Even though the oxygenated chains are oxidized by nitroblue tetrazolium, much less overall reduction of nitroblue tetrazolium is observed at high oxygen pressures. This phenomenon is attributed to the reoxidation by oxygen of both the tetrazolinyl radical and the formazan. The reaction with nitroblue tetrazolium is also found to contribute to enhanced oxidation at intermediate oxygen pressures. This behavior is explained by the two-electron reaction with nitroblue tetrazolium and the oxygen dependence of the various processes involved in the reaction of nitroblue tetrazolium.