Reaction: (1) para-substituted 2-methoxyphenol + O2 = meta-substituted 3-methoxy-1,2-benzoquinone + H2O
(2) 2 para-substituted 2,6-dimethoxyphenol + O2 = 2 meta-substituted 3-methoxy-1,2-benzoquinone + 2 methanol
(3) 2 meta-substituted 3-methoxybenzene-1,2-diol + O2 = 2 meta-substituted 3-methoxy-1,2-benzoquinone + 2 H2O
Systematic name: an ortho-methoxylated phenol:oxygen oxidoreductase (ortho-quinone-forming)
Comments: A group of coupled binuclear copper enzymes found in filamentous fungi. Unlike EC 1.14.18.1, tyrosinase, these enzymes exhibit a distinct preference for ortho-methoxylated phenolic compounds such as guaiacyl- and syringyl-type phenolics derived from lignin depolymerization. When acting on syringyl-type substrates (having two ortho-methoxy groups), but not on guaiacyl-type substrates (a single ortho-methoxy group), the enzyme catalyses oxidative demethoxylation releasing methanol. The enzymes accommodate a wide range of methoxylated phenolic substrates, with variability in the para-position substituent relative to the phenolic hydroxyl.
Links to other databases: BRENDA, EXPASY, KEGG, MetaCyc, CAS registry number:
References:
1. Frommhagen, M., Mutte, S.K., Westphal, A.H., Koetsier, M.J., Hinz, S.WA., Visser, J., Vincken, J.P., Weijers, D., van Berkel, W.JH., Gruppen, H. and Kabel, M.A. Boosting LPMO-driven lignocellulose degradation by polyphenol oxidase-activated lignin building blocks. Biotechnol Biofuels 10 (2017) 121. [PMID: 28491137]
2. de Oliveira Gorgulho Silva, C., Vuillemin, M., Kabel, M.A., van Berkel, W.JH., Meyer, A.S. and Agger, J.W. Polyphenol oxidase products are priming agents for LPMO peroxygenase activity. ChemSusChem 16 (2023) e202300559. [PMID: 37278305]
3. de, O., G. Silva, C., Sun, P., Barrett, K., Sanders, M.G., van Berkel, W.JH., Kabel, M.A., Meyer, A.S. and Agger, J.W. Polyphenol Oxidase Activity on Guaiacyl and Syringyl Lignin Units. Angew. Chem. Int. Ed. Engl. 63 (2024) e202409324. [PMID: 39285758]