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 00:00:00 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), Vol. 173:2; ISSN 0021-9193
• Country of Publication: United States
• Language: English

Related Subjects

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