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Total records: 126
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[ 2013 ] Churakova E, Arends IWCE, Hollmann F Increasing the Productivity of Peroxidase-Catalyzed Oxyfunctionalization: A Case Study on the Potential of Two-Liquid-Phase Systems ChemCatChem, 5: 565-568

[ 2013 ] Hahn F, Ullrich R, Hofrichter M, Liers C Experimental approach to follow the spatiotemporal wood degradation in fungal microcosms Biotechnol. J., 8: 127-132

[ 2013 ] Karich A, Kluge M, Ullrich R, Hofrichter M Benzene oxygenation and oxidation by the peroxygenase of Agrocybe aegerita AMB Express, 3: 5-13

[ 2013 ] Kluge M, Ullrich R, Scheibner K, Hofrichter M Formation of naphthalene hydrates in the enzymatic conversion of 1,2-dihydronaphthalene by two fungal peroxygenases and subsequent naphthalene formation J. Mol. Cat. B, doi: 10.1016/j.molcatb.2013.08.017

[ 2013 ] Liers C, Aranda E, Strittmatter E, Piontek K, Plattner D, Zorn H, Ullrich R, Hofrichter M Phenol oxidation by DyP-type peroxidases in comparison to fungal and plant peroxidases J. Mol. Cat. B, doi: 10.1016/j.molcatb.2013.09.025

[ 2013 ] Liers C, Pecyna MJ, Kellner H, Worrich A, Zorn H, Steffen KT, Hofrichter M, Ullrich R Substrate oxidation by dye-decolorizing peroxidases (DyPs) from wood- and litter-degrading agaricomycetes compared to other fungal and plant heme-peroxidases Appl. Microbiol. Biotechnol., 97: 5839-5849

Aromatic peroxygenase (APO) is an extracellular enzyme produced by the agaric basidiomycete Agrocybe aegerita that catalyzes diverse peroxide-dependent oxyfunctionalization reactions. Here we describe the oxygenation of the unactivated aromatic ring of benzene with hydrogen peroxide as co-substrate. The optimum pH of the reaction was around 7 and it proceeded via an initial epoxide intermediate that re-aromatized in aqueous solution to form phenol. Identity of the epoxide intermediate as benzene oxide was proved by a freshly prepared authentic standard using GC-MS and LC-MS analyses. Second and third [per]oxygenation was also observed and resulted in the formation of further hydroxylation and following [per]oxidation products: hydroquinone and p-benzoquinone, catechol and o-benzoquinone as well as 1,2,4-trihydroxybenzene and hydroxy-p-benzoquinone, respectively. Using H218O2 as co-substrate and ascorbic acid as radical scavenger, inhibiting the formation of peroxidation products (e.g., p-benzoquinone), the origin of the oxygen atom incorporated into benzene or phenol was proved to be the peroxide. Apparent enzyme kinetic constants (kcat, Km) for the peroxygenation of benzene were estimated to be around 8 s-1 and 3.6 mM. These results raise the possibility that peroxygenases may be useful for enzymatic syntheses of hydroxylated benzene derivatives under mild conditions.