Fischer V, Harman L S, West P R, Mason R P
Chem Biol Interact. 1986 Nov;60(2):115-27. doi: 10.1016/0009-2797(86)90021-9.
The oxidation of the phenacetin metabolites p-phenetidine and acetaminophen by peroxidases was investigated. Free radical intermediates from both metabolites were detected using fast-flow ESR spectroscopy. Oxidation of acetaminophen with either lactoperoxidase and hydrogen peroxide or horseradish peroxidase and hydrogen peroxide resulted in the formation of the N-acetyl-4-aminophenoxyl free radical. Totally resolved spectra were obtained and completely analyzed. The radical concentration was dependent on the square root of the enzyme concentration, indicating second-order decay of the radical, as is consistent with its dimerization or disproportionation. The horseradish peroxidase/hydrogen peroxide-catalyzed oxidation of p-phenetidine (4-ethoxyaniline) at pH 7.5-8.5 resulted in the one-electron oxidation products, the 4-ethoxyaniline cation free radical. The ESR spectra were well resolved and could be unambiguously assigned. Again, the enzyme dependence of the radical concentration indicated a second-order decay. The ESR spectrum of the conjugate base of the 4-ethoxyaniline cation radical, the neutral 4-ethoxyphenazyl free radical, was obtained at pH 11-12 by the oxidation of p-phenetidine with potassium permanganate.
研究了过氧化物酶对非那西丁代谢产物对乙氧基苯胺和对乙酰氨基酚的氧化作用。使用快速流动电子顺磁共振波谱法检测了两种代谢产物的自由基中间体。用乳过氧化物酶和过氧化氢或辣根过氧化物酶和过氧化氢氧化对乙酰氨基酚，导致形成N-乙酰-4-氨基苯氧基自由基。获得了完全分辨的光谱并进行了全面分析。自由基浓度取决于酶浓度的平方根，表明自由基呈二级衰减，这与其二聚化或歧化反应一致。在pH 7.5 - 8.5条件下，辣根过氧化物酶/过氧化氢催化氧化对乙氧基苯胺（4-乙氧基苯胺），生成单电子氧化产物4-乙氧基苯胺阳离子自由基。电子顺磁共振波谱得到了很好的分辨，并且可以明确归属。同样，自由基浓度对酶的依赖性表明其呈二级衰减。在pH 11 - 12条件下，通过用高锰酸钾氧化对乙氧基苯胺，获得了4-乙氧基苯胺阳离子自由基共轭碱即中性4-乙氧基苯甲酰自由基的电子顺磁共振波谱。
