Demonstration of carbon-carbon bond cleavage of acetyl coenzyme A by using isotopic exchange catalyzed by the CO dehydrogenase complex from acetate-grown Methanosarcina thermophila

Journal Article · Tue Jan 01 04:00:00 EST 1991 · Journal of Bacteriology; (USA)

OSTI ID:6150528

Raybuck, S A; Ramer, S E; Abbanat, D R; Peters, J W; Orme-Johnson, W H; Ferry, J G; Walsh, C T ^[1]

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1. Harvard Medical School, Boston, MA (USA)

The purified nickel-containing CO dehydrogenase complex isolated from methanogenic Methanosarcina thermophila grown on acetate is able to catalyze the exchange of (1-{sup 14}C) acetyl-coenzyme A (CoA) (carbonyl group) with {sup 12}CO as well as the exchange of (3'-{sup 32}P)CoA with acetyl-CoA. Kinetic parameters for the carbonyl exchange have been determined: Km (acetyl-CoA) = 200 microM, Vmax = 15 min-1. CoA is a potent inhibitor of this exchange (Ki = 25 microM) and is formed under the assay conditions because of a slow but detectable acetyl-CoA hydrolase activity of the enzyme. Kinetic parameters for both exchanges are compared with those previously determined for the acetyl-CoA synthase/CO dehydrogenase from the acetogenic Clostridium thermoaceticum. Collectively, these results provide evidence for the postulated role of CO dehydrogenase as the key enzyme for acetyl-CoA degradation in acetotrophic bacteria.

• OSTI ID: 6150528
• Journal Information: Journal of Bacteriology; (USA), Journal Name: Journal of Bacteriology; (USA) Vol. 173:2; ISSN JOBAA; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

550501* -- Metabolism-- Tracer Techniques
59 BASIC BIOLOGICAL SCIENCES
ACETATES
BACTERIA
BETA DECAY RADIOISOTOPES
BETA-MINUS DECAY RADIOISOTOPES
CARBON 14 COMPOUNDS
CARBOXYLIC ACID SALTS
COENZYMES
DAYS LIVING RADIOISOTOPES
ENZYME ACTIVITY
ENZYME INHIBITORS
ENZYMES
ISOTOPE APPLICATIONS
ISOTOPE DILUTION
ISOTOPES
ISOTOPIC EXCHANGE
LABELLED COMPOUNDS
LIGHT NUCLEI
METABOLISM
METHANOGENIC BACTERIA
MICROORGANISMS
NUCLEI
ODD-ODD NUCLEI
OXIDOREDUCTASES
PHOSPHORUS 32
PHOSPHORUS ISOTOPES
RADIOISOTOPES
TRACER TECHNIQUES