Effect of pH on tritium exchange and hydrogen production and uptake in free-living cells and in bacteroids of Bradyrhizobium japonicum
Soybean nodule bacteroids and Bradyrhizobium japonicum free-living cells induced for H/sub 2/-uptake hydrogenase, actively catalyze the evolution of H/sub 2/ in a reaction highly dependent on the pH. The optimal pHs for the evolution and uptake reactions were 4.0 and 7.5-8.0, respectively. No differences were found between free-living cells and bacteroids with respect to hydrogen acceptor specificity, although absolute rates of H/sub 2/ uptake were higher for free-living cells. Both types of cells were able to evolve hydrogen from reduced methyl viologen at low pH. These intact cells also catalyzed the exchange reaction between tritium and water in the absence of oxygen. The pH profile of the exchange activity showed two peaks at values near the optimal pHs for the evolution and uptake reactions.
- Research Organization:
- Instituto de Catalisis, CSIC, Madrid, Spain
- OSTI ID:
- 5478631
- Journal Information:
- Arch. Biochem. Biophys.; (United States), Journal Name: Arch. Biochem. Biophys.; (United States) Vol. 259:2; ISSN ABBIA
- Country of Publication:
- United States
- Language:
- English
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Related Subjects
Kinetics
& Toxicology-- Animals
Plants
Microorganisms
& Cells
63 RADIATION, THERMAL, AND OTHER ENVIRON. POLLUTANT EFFECTS ON LIVING ORGS. AND BIOL. MAT.
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
ENZYME ACTIVITY
ENZYMES
GLYCINE HISPIDA
HYDROGEN COMPOUNDS
HYDROGEN ISOTOPES
HYDROGEN PRODUCTION
HYDROGENASES
ISOTOPES
LEGUMINOSAE
LIGHT NUCLEI
MICROORGANISMS
NUCLEI
ODD-EVEN NUCLEI
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PH VALUE
PLANTS
RADIOISOTOPES
RADIONUCLIDE KINETICS
RHIZOBIUM
TRITIUM
UPTAKE
WATER
YEARS LIVING RADIOISOTOPES