Acetylene inhibition of Azotobacter vinelandii hydrogenase: Acetylene binds tightly to the large subunit

Journal Article · Tue Mar 31 04:00:00 EST 1992 · Biochemistry; (United States)

OSTI ID:5403381

Sun, Jinhua; Hyman, M R; Arp, D J ^[1]

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1. Oregon State Univ., Corvallis (United States)

Acetylene is a slow-binding inhibitor of the Ni- and Fe-containing dimeric hydrogenase isolated from Azotobacter vinelandii. Acetylene was released from hydrogenase during the recovery from inhibition. This indicates that no transformation of acetylene to another compound occurred as a result of the interaction with hydrogenase. However, the release of C{sub 2}H{sub 2} proceeds more rapidly than the recovery of activity, which indicates that release of C{sub 2}H{sub 2} is not sufficient for recovery of activity. Acetylene binds tightly to native hydrogenase; hydrogenase and radioactivity coelute from a gel permeation column following inhibition with {sup 14}C{sub 2}H{sub 2}. Acetylene, or a derivative, remains bound to the large 65,000 MW subunit (and not to the small 35,000 MW subunit) of hydrogenase following denaturation as evidence by SDS-PAGE and fluorography of {sup 14}C{sub 2}H{sub 2}-inhibited hydrogenase. This result suggests that C{sub 2}H{sub 2}, and by analogy H{sub 2}, binds to and is activated by the large subunit of this dimeric hydrogenase. Radioactivity is lost from {sup 14}C{sub 2}H{sub 2}-inhibited protein during recovery. The inhibition is remarkably specific for C{sub 2}H{sub 2}; propyne, butyne, and ethylene are not inhibitors.

• DOE Contract Number: FG06-90ER20013
• OSTI ID: 5403381
• Journal Information: Biochemistry; (United States), Journal Name: Biochemistry; (United States) Vol. 31:12; ISSN 0006-2960; ISSN BICHA
• Country of Publication: United States
• Language: English

Related Subjects

550201* -- Biochemistry-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETYLENE
ALKYNES
AZOTOBACTER
BACTERIA
BIOCHEMISTRY
BIOLOGICAL EFFECTS
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CHEMISTRY
ENZYME INHIBITORS
ENZYMES
HYDROCARBONS
HYDROGENASES
INHIBITION
LABELLED COMPOUNDS
MICROORGANISMS
ORGANIC COMPOUNDS
OXIDOREDUCTASES
PROTEINS