Hydrogen-ubiquinone oxidoreductase activity by the Bradyrhizobium japonicum membrane-bound hydrogenase

FEMS Microbiol Lett. 1993 Jul 1;110(3):257-64. doi: 10.1111/j.1574-6968.1993.tb06331.x.

Abstract

The Bradyrhizobium japonicum heterodimeric nickel-iron hydrogenase efficiently catalyzed H2-ubiquinone-1 oxidoreductase activity at rates up to 47% of the maximal rates obtained using the artificial electron acceptor methylene blue. Gel filtration chromatography and SDS-polyacrylamide gel electrophoresis experiments demonstrated that the purified enzyme was a heterodimer containing only the 65 kDa and 33 kDa subunits. Reduced minus oxidized absorption difference spectra demonstrated the absence of detectable cytochromes. The H2-ubiquinone-1 oxidoreductase activity of both the purified heterodimeric hydrogenase and membranes was significantly inhibited by 2-n-heptyl-4-hydroxyquinoline-N-oxide and antimycin A, inhibitors known to act in the quinone region of electron transport chains. Our results are the first report of H2-ubiquinone oxidoreductase activity by a purified hydrogenase.

Publication types

  • Research Support, U.S. Gov't, P.H.S.

MeSH terms

  • Antimycin A / pharmacology
  • Cytochromes / analysis
  • Electron Transport
  • Hydrogen / metabolism*
  • Hydrogenase / chemistry
  • Hydrogenase / metabolism*
  • Hydroxyquinolines / pharmacology
  • Membranes / enzymology
  • Methylene Blue / metabolism
  • Oxidation-Reduction
  • Oxidoreductases / chemistry
  • Oxidoreductases / metabolism*
  • Rhizobiaceae / enzymology*
  • Ubiquinone / metabolism*

Substances

  • Cytochromes
  • Hydroxyquinolines
  • Ubiquinone
  • 2-(n-heptyl)-4-hydroxyquinoline N-oxide
  • Antimycin A
  • Hydrogen
  • Oxidoreductases
  • nickel-iron hydrogenase
  • Hydrogenase
  • Methylene Blue