title: Purification and characterization of F420H2-dehydrogenase from Methanolobus tindarius.
abstract: The oxidation of F420H2 (reduced coenzyme F420) is a key reaction in the final step of methanogenesis. This step is catalyzed in Methanolobus tindarius by the membrane-bound F420H2-dehydrogenase which was purified 31-fold to apparent homogeneity. The apparent molecular mass of the native enzyme was 120 kDa. Sodium dodecyl sulfate/polyacrylamide gel electrophoresis revealed the presence of five different subunits of apparent molecular masses of 45 kDa, 40 kDa, 22 kDa, 18 kDa and 17 kDa. The purified F420H2-dehydrogenase, which was yellowish, contained 16 +/- 2 mol iron and 16 +/- 3 mol acid-labile sulfur/mol enzyme. No flavin could be detected. The oxygen-stable enzyme catalyzed the oxidation of F420H2 (apparent Km = 5.4 microM) with methylviologen and metronidazole as electron acceptors at a specific rate of 13 mumol.min-1.mg-1 (kcat = 25.5 s-1). The isoelectric point was at pH 5.0. The temperature optimum was at 37 degrees C and the pH optimum at 6.8.
authors.affiliation: Institut für Mikrobiologie, Georg-August-Universität Göttingen, Federal Republic of Germany.
authors.forename: P
authors.initials: P
authors.lastname: Haase
authors.forename: U
authors.initials: U
authors.lastname: Deppenmeier
authors.forename: M
authors.initials: M
authors.lastname: Blaut
authors.forename: G
authors.initials: G
authors.lastname: Gottschalk
mesh_terms: D002384:Catalysis; D002846:Chromatography, Affinity; D004591:Electrophoresis, Polyacrylamide Gel; D019605:Euryarchaeota / Q000201:enzymology*; D007526:Isoelectric Point; D008970:Molecular Weight; D010084:Oxidation-Reduction; D010088:Oxidoreductases / Q000302:isolation & purification* / Q000378:metabolism; D013057:Spectrum Analysis
chemical_list: C072742:F420H2 dehydrogenase; D010088:Oxidoreductases