Acetylene is an active-site-directed, slow-binding, reversible inhibitor of Azotobacter vinelandii hydrogenase

Journal Article · Tue Oct 06 00:00:00 EDT 1987 · Biochemistry; (United States)

DOI:https://doi.org/10.1021/bi00394a023· OSTI ID:5403078

Hyman, M R; Arp, D J

The inhibition of purified and membrane-bound hydrogenase from Azotobacter vinelandii by dihydrogen-free acetylene was investigated. The inhibition was a time-dependent process which exhibited first-order kinetics. Both H/sub 2/ and CO protected against the inhibition by acetylene. K/sub protect(app)/ values of 0.41 and 24 ..mu..M were derived for these gases, respectively. Both H/sub 2/-oxidizing activity and the tritium exchange capacity of the purified enzyme were inhibited at the same rate by acetylene. Removal of acetylene reversed the inhibition for both the purified and the membrane-associated form of the enzyme. The purified hydrogenases from both Rhizobium japonicum and Alcaligenes eutrophus H16 were also inhibited by acetylene in a time-dependent fashion. These findings suggest that acetylene is an active-site-directed, slow-binding, reversible inhibitor of some membrane-bound hydrogenases from aerobic bacteria.

• Research Organization: Univ. of California, Riverside
• DOE Contract Number: FG03-84ER13257
• OSTI ID: 5403078
• Journal Information: Biochemistry; (United States), Vol. 26:20
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
ACETYLENE
BIOCHEMICAL REACTION KINETICS
BIOCHEMISTRY
HYDROGENASES
INHIBITION
AZOTOBACTER
CARBON MONOXIDE
CELL MEMBRANES
ENZYME INHIBITORS
GAS CHROMATOGRAPHY
OXIDATION
PURIFICATION
TIME DEPENDENCE
TRITIUM COMPOUNDS
ALKYNES
BACTERIA
CARBON COMPOUNDS
CARBON OXIDES
CELL CONSTITUENTS
CHALCOGENIDES
CHEMICAL REACTIONS
CHEMISTRY
CHROMATOGRAPHY
ENZYMES
HYDROCARBONS
KINETICS
LABELLED COMPOUNDS
MEMBRANES
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
REACTION KINETICS
SEPARATION PROCESSES
550201* - Biochemistry- Tracer Techniques