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

Journal Article · Tue Oct 06 04:00:00 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), Journal Name: Biochemistry; (United States) Vol. 26:20; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

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