(Catalytic mechanism of hydrogenase from aerobic N sub 2 -fixing microorganisms)

Technical Report · Mon Jan 01 04:00:00 EST 1990

DOI:https://doi.org/10.2172/6533817· OSTI ID:6533817

Arp, D J

Hydrogenases are enzymes which catalyze reactions involving dihydrogen. They serve integral roles in a number of microbial metabolic pathways. Our research is focussed on investigations of the catalytic mechanism of the hydrogenases found in aerobic, N{sub 2}-fixing microorganisms such as Azotobacter vinelandii and the agronomically important Bradyrhizobium japonicum as well as microorganisms with similar hydrogenases. The hydrogenases isolated from these microorganisms are Ni- and Fe-containing heterodimers. Our work has focussed on three areas during the last grant period. In all cases, a central theme has been the role of inhibitors in the characteristics under investigation. In addition, a number of collaborative efforts have yielded interesting results. In metalloenzymes such as hydrogenase, inhibitors often influence the activity of the enzyme through ligand interactions with redox centers, often metals, within the enzyme. Therefore, investigations of the ability of various compounds to inhibit an enzyme's activity, as well as the mechanism of inhibition, can provide insight into the catalytic mechanism of the enzyme as well as the role of various redox centers in catalysis. We have investigated in detail four inhibitors of A. vinelandii and the results are summarized here. The influence of these inhibitors on the spectral properties of the enzyme are summarized. Electron paramagnetic resonance and ultraviolet spectra investigations are discussed. 9 figs.

• Research Organization: California Univ., Riverside, CA (USA)
• Sponsoring Organization: DOE/ER
• DOE Contract Number: FG03-84ER13257
• OSTI ID: 6533817
• Report Number(s): DOE/ER/13257-T1; ON: DE91000126
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550500 -- Metabolism
59 BASIC BIOLOGICAL SCIENCES
ACETYLENE
ALKYNES
AZOTOBACTER
BACTERIA
BIOCHEMICAL REACTION KINETICS
BIOLOGICAL EFFECTS
BIOLOGICAL PATHWAYS
CATALYSIS
CHALCOGENIDES
CHEMICAL REACTIONS
COORDINATED RESEARCH PROGRAMS
CYANIDES
DOCUMENT TYPES
ELECTRON SPIN RESONANCE
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
HYDROCARBONS
HYDROGENASES
INHIBITION
KINETICS
MAGNETIC RESONANCE
MICROORGANISMS
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN CYCLE
NITROGEN FIXATION
NITROGEN OXIDES
ORGANIC COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PROGRESS REPORT
REACTION KINETICS
RESEARCH PROGRAMS
RESONANCE
SPECTRA
ULTRAVIOLET SPECTRA