title: Initial steps in the anoxic metabolism of cholesterol by the denitrifying Sterolibacterium denitrificans.
abstract: The anoxic metabolism of the ubiquitous triterpene cholesterol is challenging because of its complex chemical structure, low solubility in water, low number of active functional groups, and the presence of four alicyclic rings and two quaternary carbon atoms. Consequently, the aerobic metabolism depends on oxygenase catalyzed reactions requiring molecular oxygen as co-substrate. Sterolibacterium denitrificans is shown to metabolize cholesterol anoxically via the oxidation of ring A, followed by an oxygen-independent hydroxylation of the terminal C-25 of the side chain. The anaerobic hydroxylation of a tertiary carbon using water as oxygen donor is unprecedented and may be catalyzed by a novel molybdenum containing enzyme.
authors.affiliation: Mikrobiologie, Fakultät für Biologie, Universität Freiburg, Schänzlestrasse 1, D-79104 Freiburg, Germany.
authors.forename: Yin-Ru
authors.initials: YR
authors.lastname: Chiang
authors.forename: Wael
authors.initials: W
authors.lastname: Ismail
authors.forename: Michael
authors.initials: M
authors.lastname: Müller
authors.forename: Georg
authors.initials: G
authors.lastname: Fuchs
mesh_terms: D000332:Aerobiosis / Q000502:physiology; D000693:Anaerobiosis / Q000502:physiology; D002784:Cholesterol / Q000378:metabolism*; D006090:Gram-Negative Bacteria / Q000201:enzymology / Q000254:growth & development*; D008982:Molybdenum / Q000378:metabolism; D010084:Oxidation-Reduction; D010105:Oxygenases / Q000378:metabolism
chemical_list: D008982:Molybdenum; D002784:Cholesterol; D010105:Oxygenases