高铁血红蛋白催化3-羟基犬尿氨酸与过氧化氢的氧化反应。
Oxidation of 3-hydroxykynurenine catalyzed by methemoglobin with hydrogen peroxide.
作者信息
Ishii T, Iwahashi H, Sugata R, Kido R
机构信息
Department of Biochemistry, Wakayama Medical College, Japan.
出版信息
Free Radic Biol Med. 1992;13(1):17-20. doi: 10.1016/0891-5849(92)90160-i.
Methemoglobin (metHb) with H2O2 catalyzed the oxidation of 3-hydroxykynurenine (3-HKY) in the reaction mixture of metHb, 3-HKY, and H2O2. The spectrophotometric experiments suggest the following mechanism for the 3-HKY oxidation by metHb with H2O2. MetHb first reacts with H2O2 to form the ferryl complex of Hb. This species then oxidizes 3-HKY, while it returns to metHb. 3-HKY was more reactive with the ferryl complex than glutathione but less reactive than ascorbic acid. Scavengers of the hydroxyl radical, dimethyl sulfoxide and ethanol, scarcely inhibited the 3-HKY oxidation by metHb with H2O2. Desferrioxamine, a metal chelator, hardly suppressed the 3-HKY oxidation. These results indicate that the hydroxyl radical is not involved in the 3-HKY oxidation by metHb with H2O2.
高铁血红蛋白（metHb）与过氧化氢（H₂O₂）在高铁血红蛋白、3 - 羟基犬尿氨酸（3 - HKY）和H₂O₂的反应混合物中催化3 - 羟基犬尿氨酸的氧化。分光光度实验表明高铁血红蛋白与H₂O₂氧化3 - HKY的机制如下。高铁血红蛋白首先与H₂O₂反应形成血红蛋白的高铁酰复合物。然后该物质氧化3 - HKY，同时又变回高铁血红蛋白。3 - HKY与高铁酰复合物的反应性比谷胱甘肽高，但比抗坏血酸低。羟基自由基清除剂二甲基亚砜和乙醇几乎不抑制高铁血红蛋白与H₂O₂对3 - HKY的氧化。金属螯合剂去铁胺几乎不能抑制3 - HKY的氧化。这些结果表明羟基自由基不参与高铁血红蛋白与H₂O₂对3 - HKY的氧化。
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