Properties of the methane mono-oxygenase from extracts of Methylosinus trichosporium OB3b and evidence for its similarity to the enzyme from Methylococcus capsulatus (Bath).
1. The methane mono-oxygenase from Methylosinus trichosporium OB3b was soluble. The only suitable electron donor was NAD(P)H, neither sodium L-ascorbate nor electrons derived from the oxidation of methanol could substitute for NAD(P)H. Evidence is presented for the existence of an NAD+-linked formaldehyde dehydrogenase. 2. Mono-oxygenase activity was not inhibited by a range of potential inhibitors including potassium cyanide, amytal, carbon monoxide or various metal-chelating agents, although 8-hydroxyquinoline and ethyne were effective in this respect. 3. Although the enzyme preparations were unstable on storage, the crude extract could be resolved into two components by ion-exchange chromatography. Activity could be restored to one of the components on addition of purified components from Methylococcus capsulatus (Bath). 4. Cross-reactivity of mono-oxygenase components and other similarities between the enzymes from M. trichosporium and M. capsulatus are discussed. The properties of the M. trichosporium methane mono-oxygenase reported here are contrasted with the properties of the same enzyme reported by others.
D000445:Aldehyde Oxidoreductases / Q000378:metabolism; D001419:Bacteria / Q000201:enzymology*; D005557:Formaldehyde; D007700:Kinetics; D008697:Methane; D010105:Oxygenases / Q000378:metabolism*; D013045:Species Specificity
D005557:Formaldehyde; D010105:Oxygenases; D000445:Aldehyde Oxidoreductases; D008697:Methane