@misc{KinnePorajKobielskaUllrichetal., author = {Kinne, Matthias and Poraj-Kobielska, Marzena and Ullrich, Ren{\´e} and Nousiainen, Paula and Sipil{\"a}, Jussi and Scheibner, Katrin and Hammel, Kenneth E. and Hofrichter, Martin}, title = {Oxidative cleavage of non-phenolic b-O-4 lignin model dimers by an extracellular aromatic peroxygenase}, series = {Holzforschung}, volume = {65}, journal = {Holzforschung}, number = {5}, issn = {1437-434X}, doi = {10.1515/HF.2011.057}, pages = {673 -- 679}, abstract = {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.}, language = {en} } @misc{KiebistSchmidtkeZimmermannetal., author = {Kiebist, Jan and Schmidtke, Kai-Uwe and Zimmermann, J{\"o}rg and Kellner, Harald and Jehmlich, Nico and Ullrich, Ren{\´e} and Z{\"a}nder, Daniel and Hofrichter, Martin and Scheibner, Katrin}, title = {A peroxygenase from Chaetomium globosum catalyzes the selective oxygenation of testosterone}, series = {ChemBioChem}, volume = {18}, journal = {ChemBioChem}, number = {6}, issn = {1439-7633}, doi = {10.1002/cbic.201600677}, pages = {563 -- 569}, abstract = {Unspecific peroxygenases (UPO, EC 1.11.2.1) secreted by fungi open an efficient way to selectively oxyfunctionalize diverse organic substrates including less activated hydrocarbons by transferring peroxide-borne oxygen. Herein, we investigated a cell-free approach to incorporate epoxy and hydroxyl functionalities directly into the bulky molecule of testosterone by a novel unspecific peroxygenase that was produced by the ascomycetous fungus Chaetomium globosum in a complex medium rich in carbon and nitrogen. Purification by fast protein liquid chromatography revealed two enzyme fractions with the same molecular mass of 36 kDa and specific activities of 4.4 to 12 U mg-1. Whereas well-known UPOs of Agrocybe aegerita (AaeUPO) and Marasmius rotula (MroUPO) failed to convert testosterone in a comparative study, the UPO of C. globosum (CglUPO) accepted testosterone as substrate and converted it with up to 7,000 total turnovers (TTN) into two oxygenated products: the 4,5-epoxide of testosterone in β-configuration and 16α-hydroxytestosterone. The reaction was performed at 100-mg scale resulting in the formation of about 90 \% of the epoxide and 10 \% of the hydroxylation product, which both could be isolated with purities above 96 \%. Thus, CglUPO may be a promising biocatalyst for the oxyfunctionalization of bulky steroids and provide a useful tool for the synthesis of pharmaceutically relevant steroidal molecules.}, language = {en} } @misc{HofrichterKellnerHerzogetal., author = {Hofrichter, Martin and Kellner, Harald and Herzog, Robert and Karich, Alexander and Kiebist, Jan and Scheibner, Katrin and Ullrich, Ren{\´e}}, title = {Peroxide-Mediated Oxygenation of Organic Compounds by Fungal Peroxygenases}, series = {Antioxidants}, volume = {11}, journal = {Antioxidants}, number = {1}, issn = {2076-3921}, doi = {10.3390/antiox11010163}, pages = {1 -- 21}, abstract = {Unspecific peroxygenases (UPOs), whose sequences can be found in the genomes of thousands of filamentous fungi, many yeasts and certain fungus-like protists, are fascinating biocatalysts that transfer peroxide-borne oxygen (from H2O2 or R-OOH) with high efficiency to a wide range of organic substrates, including less or unactivated carbons and heteroatoms. A twice-proline-flanked cysteine (PCP motif) typically ligates the heme that forms the heart of the active site of UPOs and enables various types of relevant oxygenation reactions (hydroxylation, epoxidation, subsequent dealkylations, deacylation, or aromatization) together with less specific one-electron oxidations (e.g., phenoxy radical formation). In consequence, the substrate portfolio of a UPO enzyme always combines prototypical monooxygenase and peroxidase activities. Here, we briefly review nearly 20 years of peroxygenase research, considering basic mechanistic, molecular, phylogenetic, and biotechnological aspects.}, language = {en} }