TY - GEN A1 - Kinne, Matthias A1 - Poraj-Kobielska, Marzena A1 - Ullrich, René A1 - Nousiainen, Paula A1 - Sipilä, Jussi A1 - Scheibner, Katrin A1 - Hammel, Kenneth E. A1 - Hofrichter, Martin T1 - Oxidative cleavage of non-phenolic b-O-4 lignin model dimers by an extracellular aromatic peroxygenase T2 - Holzforschung N2 - The extracellular aromatic peroxygenase of the agaric fungus Agrocybe aegerita catalyzed the H2O2-dependent cleavage of non-phenolic arylglycerol-b-aryl ethers (b-O-4 ethers). For instance 1-(3,4-dimethoxyphenyl)-2-(2-methoxy-phenoxy)pro- pane-1,3-diol, a recalcitrant dimeric lignin model compound that represents the major non-phenolic substructure in lignin, was selectively O-demethylated at the para-methoxy group to give formaldehyde and 1-(4-hydroxy-3-methoxyphenyl)- 2-(2-methoxyphenoxy)propane-1,3-diol. The phenol moiety of the latter compound was then enzymatically oxidized into phenoxy radicals and a quinoid cation, which initiated the autocatalytic cleavage of the dimer and the formation of monomers such as 2-methoxy-1,4-benzoquinone and phenoxyl-substituted propionic acid. The introduction of 18O from H218O2 and H218O at different positions into the products provided information about the routes of ether cleavage. Studies with a 14C-labeled lignin model dimer showed that more than 70% of the intermediates formed were further coupled to form polymers with molecular masses above 10 kDa. The results indicate that fungal aromatic peroxyge- nases may be involved in the bioconversion of methoxylated plant ingredients originating from lignin or other sources. KW - Agrocybe aegerita KW - hydroxylation KW - lignin model compound KW - 0-dealkylation KW - peroxidase KW - peroxygenase Y1 - 2014 UR - https://opus4.kobv.de/opus4-UBICO/frontdoor/index/index/docId/11652 SN - 1437-434X VL - 65 IS - 5 SP - 673 EP - 679 ER -