title: 25-Hydroxyvitamin D3 Synthesis by Enzymatic Steroid Side-Chain Hydroxylation with Water.
abstract: The hydroxylation of vitamin D3 (VD3, cholecalciferol) side chains to give 25-hydroxyvitamin D3 (25OHVD3) is a crucial reaction in the formation of the circulating and biologically active forms of VD3 . It is usually catalyzed by cytochrome P450 monooxygenases that depend on complex electron donor systems. Cell-free extracts and a purified Mo enzyme from a bacterium anaerobically grown with cholesterol were employed for the regioselective, ferricyanide-dependent hydroxylation of VD3 and proVD3 (7-dehydrocholesterol) into the corresponding tertiary alcohols with greater than 99 % yield. Hydroxylation of VD3 strictly depends on a cyclodextrin-assisted isomerization of VD3 into preVD3 , the actual enzymatic substrate. This facile and robust method developed for 25OHVD3 synthesis is a novel example for the concept of substrate-engineered catalysis and offers an attractive alternative to chemical or O2  /electron-donor-dependent enzymatic procedures.
authors.affiliation: Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany.
authors.forename: Markus
authors.initials: M
authors.lastname: Warnke
authors.affiliation: Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany.
authors.forename: Tobias
authors.initials: T
authors.lastname: Jung
authors.affiliation: Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany.
authors.forename: Juri
authors.initials: J
authors.lastname: Dermer
authors.affiliation: Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany.
authors.forename: Karin
authors.initials: K
authors.lastname: Hipp
authors.affiliation: Department of Proteomics, Helmholtz Centre of Environmental Sciences, Permoserstr. 15, 04318, Leipzig, Germany.
authors.forename: Nico
authors.initials: N
authors.lastname: Jehmlich
authors.affiliation: Department of Proteomics, Helmholtz Centre of Environmental Sciences, Permoserstr. 15, 04318, Leipzig, Germany.
authors.forename: Martin
authors.initials: M
authors.lastname: von Bergen
authors.affiliation: Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, 79104, Freiburg, Germany.
authors.forename: Sascha
authors.initials: S
authors.lastname: Ferlaino
authors.affiliation: Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, 79104, Freiburg, Germany.
authors.forename: Alexander
authors.initials: A
authors.lastname: Fries
authors.affiliation: Institute of Pharmaceutical Sciences, Albert-Ludwigs-Universität Freiburg, Albertstrasse 25, 79104, Freiburg, Germany.
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.affiliation: Faculty of Biology - Microbiology, Albert-Ludwigs-Universität Freiburg, Schänzlestrasse 1, 79104, Freiburg, Germany. matthias.boll@biologie.uni-freiburg.de.
authors.forename: Matthias
authors.initials: M
authors.lastname: Boll
mesh_terms: D002762:Cholecalciferol / Q000138:chemical synthesis*; D006900:Hydroxylation; D013256:Steroids / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D013256:Steroids; D014867:Water; D002762:Cholecalciferol
keywords: C−H activation; biotechnology; enzyme catalysis; steroids; vitamins