Properties of purified carbon monoxide dehydrogenase from Clostridium thermoaceticum, a nickel, iron-sulfur protein

Journal Article · Fri Feb 25 04:00:00 EST 1983 · J. Biol. Chem.; (United States)

OSTI ID:6001028

Ragsdale, S W; Clark, J E; Ljungdahl, L G; Lundie, L L; Drake, H L

Carbon monoxide dehydrogenase from Clostridium thermoaceticum has been purified to homogeneity using a strict anaerobic procedure. The enzyme has a molecular weight of about 440,000 and it consists of three each of two different subunits giving the composition ..cap alpha../sub 3/..beta../sub 3/. The molecular weight of the ..cap alpha..-subunit is 78,000 and that of the ..beta..-subunit is 71,000. Pore limit gel electrophoresis gave a molecular weight of 161,000 indicating that the enzyme dissociates to form a dimer with an ..cap alpha beta.. structure. The dimer apparently contains per mol 2 nickel, 1 zinc, 11 iron, and 14 acid-labile sulfur. The anaerobic enzyme has an iron-sulfur type spectrum, which is changed in the presence of the substrate, CO. In the presence of oxygen, which destroys the activity or CO/sub 2/, the spectrum is that of a typical iron-sulfur protein. Under acidic conditions a low molecular weight nickel factor separates from the enzyme. Viologens, methylene blue, ferredoxin, flavodoxin, and rubredoxin serve as electron acceptorrs. The enzyme has a pH optimum around 8.4. Cyanide and methyliodide inhibit the enzyme. CO reverses the cyanide inhibition but promotes the reaction with methyl iodide. The pure enzyme has no hydrogenase or formate dehydrogenase activity.

• Research Organization: Univ. of Georgia, Athens
• DOE Contract Number: AS09-79ER10499
• OSTI ID: 6001028
• Journal Information: J. Biol. Chem.; (United States), Journal Name: J. Biol. Chem.; (United States) Vol. 258:4; ISSN JBCHA
• Country of Publication: United States
• Language: English

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59 BASIC BIOLOGICAL SCIENCES
BACTERIA
CARBON 14 COMPOUNDS
CARBON COMPOUNDS
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CHEMICAL PROPERTIES
CLOSTRIDIUM
ELECTROPHORESIS
ELEMENTS
ENZYME ACTIVITY
ENZYMES
HEMIACETAL DEHYDROGENASES
IRON
LABELLED COMPOUNDS
METALS
MICROORGANISMS
MOLECULAR WEIGHT
NICKEL
NONMETALS
OXIDES
OXIDOREDUCTASES
OXYGEN COMPOUNDS
PH VALUE
SPECTRA
SULFUR
TRANSITION ELEMENTS
ULTRAVIOLET SPECTRA