Metalloporphyrin catalysed biomimetic oxidation of aryl benzyl ethers.: Implications for lignin peroxidase catalysis

Metalloporphyrin catalysed oxidation of methoxy- and methylendioxy benzyl ethers was studied. In addition to previously described carbonyl compounds and the corresponding alcohols ring oxygenated products were also isolated. Formation of quinones and quinone acetals was rationalised by the nucleophilic attack of the solvent. This proposal implies that the mechanism of lignin peroxidase catalysis is clearly different from the mechanism of aromatic oxidations catalysed by cytochrome P450. The differening molecular mechanism of oxidations catalysed by the two heme proteins was explained by comparison of active site geometries. Our study also demonstrates that a particular methoxy arene, Verbutin (1), an effective inhibitor of insect cytochrome P450s, is a potential substrate of lignin peroxidase. The high capacity of lignin peroxidase catalysed metabolism of xenobiotics renders the inhibitor all environmentally friendly agrochemical in the fight against metabolic insecticide resistance. (C) 1999 Elsevier Science Ltd. All rights reserved.