Corbett M D, Chipko B R
Biochem J. 1979 Nov 1;183(2):269-76. doi: 10.1042/bj1830269.
In the presence of chloroperoxidase, indole was oxidized by H2O2 to give oxindole as the major product. Under most conditions oxindole was the only product formed, and under optimal conditions the conversion was quantitative. This reaction displayed maximal activity at pH 4.6, although appreciable activity was observed throughout the entire pH range investigated, namely pH 2.5-6.0. Enzyme saturation by indole could not be demonstrated, up to the limit of indole solubility in the buffer. The oxidation kinetics were first-order with respect to indole up to 8 mM, which was the highest concentration of indole that could be investigated. On the other hand, 2-methylindole was not affected by H2O2 and chloroperoxidase, but was a strong inhibitor of indole oxidation. The isomer 1-methylindole was a poor substrate for chloroperoxidase oxidation, and a weak inhibitor of indole oxidation. These results suggest the possibility that chloroperoxidase oxidation of the carbon atom adjacent to the nitrogen atom in part results from hydrogen-bonding of the substrate N-H group to the enzyme active site.
在氯过氧化物酶存在的情况下，吲哚被过氧化氢氧化，主要产物为氧化吲哚。在大多数条件下，氧化吲哚是唯一形成的产物，在最佳条件下转化率是定量的。该反应在pH 4.6时表现出最大活性，尽管在整个研究的pH范围内（即pH 2.5 - 6.0）都观察到了可观的活性。直到吲哚在缓冲液中的溶解度极限，都未能证明吲哚对酶的饱和作用。在高达8 mM（这是可研究的吲哚最高浓度）时，氧化动力学对吲哚呈一级反应。另一方面，2 - 甲基吲哚不受过氧化氢和氯过氧化物酶的影响，但却是吲哚氧化的强抑制剂。异构体1 - 甲基吲哚是氯过氧化物酶氧化的不良底物，也是吲哚氧化的弱抑制剂。这些结果表明，氯过氧化物酶对与氮原子相邻的碳原子的氧化部分可能是由于底物N - H基团与酶活性位点的氢键作用。
