Green J, Dalton H
Department of Biological Sciences, University of Warwick, Coventry, West Midlands, United Kingdom.
J Biol Chem. 1989 Oct 25;264(30):17698-703.
Following the example set by studies of the mechanistic aspects of the substrate specificity of various cytochrome P-450 enzymes, we have undertaken a parallel investigation of the soluble methane monooxygenase from Methylococcus capsulatus (Bath). Soluble methane monooxygenase is a multicomponent enzyme with a broad substrate specificity. Using substrates previously tested with cytochrome P-450 enzymes and using purified enzyme preparations, this work indicates that soluble methane monooxygenase has a similar oxidative reaction mechanism to cytochrome P-450 enzymes. The evidence suggests that soluble methane monooxygenase oxidizes substrates via a nonconcerted reaction mechanism (hydrogen abstraction preceding hydroxylation) with radical or carbocation intermediates. Aromatic hydroxylation proceeds by epoxidation followed by an NIH shift.
以对各种细胞色素P - 450酶底物特异性的机制方面的研究为范例，我们对来自荚膜甲基球菌（巴斯）的可溶性甲烷单加氧酶进行了平行研究。可溶性甲烷单加氧酶是一种具有广泛底物特异性的多组分酶。使用先前用细胞色素P - 450酶测试过的底物并使用纯化的酶制剂，这项工作表明可溶性甲烷单加氧酶具有与细胞色素P - 450酶相似的氧化反应机制。证据表明，可溶性甲烷单加氧酶通过非协同反应机制（羟基化之前进行氢提取）氧化底物，存在自由基或碳正离子中间体。芳香族羟基化通过环氧化然后进行NIH迁移来进行。
