title: Epoxidation of linear, branched and cyclic alkenes catalyzed by unspecific peroxygenase.
abstract: Unspecific peroxygenases (EC 1.11.2.1) represent a group of secreted heme-thiolate proteins that are capable of catalyzing the mono-oxygenation of diverse organic compounds, using only H2O2 as a co-substrate. Here we show that the peroxygenase secreted by the fungus Agrocybe aegerita catalyzed the oxidation of 20 different alkenes. Five branched alkenes, among them 2,3-dimethyl-2-butene and cis-2-butene, as well as propene and butadiene were epoxidized with complete regioselectivity. Longer linear alkenes with a terminal double bond (e.g. 1-octene) and cyclic alkenes (e.g. cyclohexene) were converted into the corresponding epoxides and allylic hydroxylation products; oxidation of the cyclic monoterpene limonene yielded three oxygenation products (two epoxides and an alcohol). In the case of 1-alkenes, the conversion occurred with moderate stereoselectivity, in which the preponderance for the (S)-enantiomer reached up to 72% ee for the epoxide product. The apparent Michaelis-Menten constant (Km) for the epoxidation of the model substrate 2-methyl-2-butene was 5mM, the turnover number (kcat) 1.3×10(3)s(-1) and the calculated catalytic efficiency, kcat/Km, was 2.5×10(5)M(-1)s(-1). As epoxides represent chemical building blocks of high relevance, new enzymatic epoxidation pathways are of interest to complement existing chemical and biotechnological approaches. Stable and versatile peroxygenases as that of A. aegerita may form a promising biocatalytic platform for the development of such enzyme-based syntheses.
authors.affiliation: Department of Bio- and Environmental Sciences, International Graduate School of Zittau, Markt 23, 02763 Zittau, Germany. peter@ihi-zittau.de
authors.forename: Sebastian
authors.initials: S
authors.lastname: Peter
authors.forename: Matthias
authors.initials: M
authors.lastname: Kinne
authors.forename: René
authors.initials: R
authors.lastname: Ullrich
authors.forename: Gernot
authors.initials: G
authors.lastname: Kayser
authors.forename: Martin
authors.initials: M
authors.lastname: Hofrichter
mesh_terms: D055362:Agrocybe / Q000201:enzymology*; D000475:Alkenes / Q000737:chemistry / Q000378:metabolism*; D001709:Biotechnology / Q000379:methods; D002384:Catalysis; D003516:Cycloparaffins / Q000737:chemistry / Q000378:metabolism*; D004852:Epoxy Compounds / Q000378:metabolism*; D006900:Hydroxylation; D007700:Kinetics; D006899:Mixed Function Oxygenases / Q000378:metabolism*; D010084:Oxidation-Reduction; D013237:Stereoisomerism; D013379:Substrate Specificity
chemical_list: D000475:Alkenes; D003516:Cycloparaffins; D004852:Epoxy Compounds; D006899:Mixed Function Oxygenases; C022333:peroxygenase