title: Characterization of an extremely thermophilic and oxygen-stable membrane-bound hydrogenase from a marine hydrogen-oxidizing bacterium Hydrogenovibrio marinus.
abstract: The membrane-bound hydrogenase from a marine hydrogen-oxidizing bacterium Hydrogenovibrio marinus was characterized as highly oxygen-tolerant, extremely thermophilic and thermostable in its membrane-bound form. The optimum temperatures for H2 oxidation and H2 evolution were 90 and 80 degrees C, respectively. The enzyme retained 90% of its activity after heating at 70 degrees C for 50 min under air and retained full activity at 90 degrees C for 80 min under hydrogen. The optimum pH values were 5.5 (H2 evolution) and 9.4 (H2 oxidation), and the activity ratio (H2 evolution/H2 oxidation) was high (50.3) at pH 5.5. The hydrogen evolution from reduced methyl viologen continued at high temperatures and acidic pH with the continuous addition of sodium dithionite.
authors.affiliation: Department of Applied Biological Resource Sciences, Ibaraki University, Japan.
authors.forename: H
authors.initials: H
authors.lastname: Nishihara
authors.forename: Y
authors.initials: Y
authors.lastname: Miyashita
authors.forename: K
authors.initials: K
authors.lastname: Aoyama
authors.forename: T
authors.initials: T
authors.lastname: Kodama
authors.forename: Y
authors.initials: Y
authors.lastname: Igarashi
authors.forename: Y
authors.initials: Y
authors.lastname: Takamura
mesh_terms: D002462:Cell Membrane / Q000201:enzymology; D004795:Enzyme Stability; D006358:Hot Temperature; D006859:Hydrogen / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D006864:Hydrogenase / Q000378:metabolism*; D007700:Kinetics; D010084:Oxidation-Reduction; D010100:Oxygen / Q000378:metabolism; D013696:Temperature; D014737:Vibrionaceae / Q000201:enzymology* / Q000378:metabolism
chemical_list: D006859:Hydrogen; D006864:Hydrogenase; D010100:Oxygen