(Catalytic mechanism of hydrogenase from aerobic N2-fixing microorganisms). [Azotobacter vinelandii:a1]

Technical Report · Tue Jan 01 04:00:00 EST 1991

OSTI ID:5452120

The results of this DOE-sponsored project have contributed to our understanding of the catalytic mechanism of A. vinelandii hydrogenase. A group of inhibitors have been characterized. These provide information about the different types of redox clusters involved in catalysis and the roles of each. One group has already used acetylene in a study of three desulfovibrian hydrogenases and shown that onbly the NiFe hydrogenases are inhibited. The inhibitor studies are also being extended to other enzymes. We have characterized a number of special properties of A. vinelandii hydrogenase. While the NiFe dimeric hydrogenases are now recognized as a large group of similar enzymes, there are differences in the spectral and catalytic properties which are not explained by their similar redox inventories, identical subunit structures, immunological cross reactivity and conserved sequences. Surprisingly, we only see a significant EPR signal attributable to Ni after the enzyme has been inactivated with O{sub 2} and then re-reduced (though not reactivated). Acetylene, which does not substantially perterb the EPR signal of active hydrogenase, does result in a new absorption envelope in the UV-Vis spectrum. Overall, the results of this project have revealed the complex interactions of the redox clusters in catalysis through studies of inhibitor mechanisms and spectral properties. 14 refs., 9 figs.

• Research Organization: Oregon State Univ., Corvallis, OR (United States)
• Sponsoring Organization: DOE; USDOE, Washington, DC (United States)
• DOE Contract Number: FG06-90ER20013
• OSTI ID: 5452120
• Report Number(s): DOE/ER/20013-1; ON: DE91017001
• Country of Publication: United States
• Language: English

Related Subjects

550200* -- Biochemistry
550500 -- Metabolism
550700 -- Microbiology
59 BASIC BIOLOGICAL SCIENCES
ACETYLENE
ALKYNES
AMINO ACID SEQUENCE
ANTIBODIES
AZOTOBACTER
BACTERIA
BIOCHEMICAL REACTION KINETICS
CHALCOGENIDES
CHEMICAL REACTIONS
CYANIDES
DOCUMENT TYPES
ELECTRON SPIN RESONANCE
ELEMENTS
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
HYDROCARBONS
HYDROGENASES
IRON
KINETICS
MAGNETIC RESONANCE
METALLOPROTEINS
METALS
MICROORGANISMS
MOLECULAR STRUCTURE
NICKEL
NITRIC OXIDE
NITROGEN COMPOUNDS
NITROGEN OXIDES
NUCLEIC ACIDS
OLIGONUCLEOTIDES
ORGANIC COMPOUNDS
OXIDATION
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PROGRESS REPORT
PROTEINS
REACTION KINETICS
REDOX REACTIONS
REDUCTION
RESONANCE
SPECTRA
TRANSITION ELEMENTS
ULTRAVIOLET SPECTRA