Coenzyme A transferase from Clostridium acetobutylicum ATCC 824 and its role in the uptake of acids

Journal Article · Wed Feb 01 00:00:00 EST 1989 · Applied and Environmental Microbiology; (USA)

OSTI ID:5027682

Wiesenborn, D P; Rudolph, F B; Papoutsakis, E T ^[1]

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1. Rice Univ., Houston, TX (USA)

Coenzyme A (CoA) transferase from Clostridium acetobutylicum ATCC 824 was purified 81-fold to homogeneity. This enzyme was stable in the presence of 0.5 M ammonium sulfate and 20% (vol/vol) glycerol, whereas activity was rapidly lost in the absence of these stabilizers. The kinetic binding mechanism was Ping Pong Bi Bi, and the K{sub m} values at pH 7.5 and 30{degree}C for acetate, propionate, and butyrate were, respectively, 1,200, 1,000, and 660 mM, while the K{sub m} value for acetoacetyl-CoA ranged from about 7 to 56{mu}M, depending on the acid substrate. The K{sub m} values for butyrate and acetate were high relative to the intracellular concentrations of these species; consequently, in vivo enzyme activity is expected to be sensitive to changes in those concentrations. In addition to the carboxylic acids listed above, this CoA transferase was able to convert valerate, isobutyrate, and crotonate; however, the conversion of formate, n-caproate, and isovalerate was not detected. The acetate and butyrate conversion reactions in vitro were inhibited by physiological levels of acetone and butanol, and this may be another factor in the in vivo regulation of enzyme activity. The optimum pH of acetate conversion was broad, with at least 80% of maximal activity from pH 5.9 to greater than 7.8. The purified enzyme was a heterotetramer with subunit molecular weights of about 23,000 and 25,000.

• OSTI ID: 5027682
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 55:2; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
09 BIOMASS FUELS
CLOSTRIDIUM ACETOBUTYLICUM
METABOLISM
TRANSFERASES
BIOCHEMICAL REACTION KINETICS
ACETONE
BIOSYNTHESIS
BUTANOLS
CARBOXYLIC ACIDS
COENZYMES
ENZYME ACTIVITY
FERMENTATION
ALCOHOLS
BACTERIA
BIOCONVERSION
CLOSTRIDIUM
ENZYMES
HYDROXY COMPOUNDS
KETONES
KINETICS
METHANOGENIC BACTERIA
MICROORGANISMS
ORGANIC ACIDS
ORGANIC COMPOUNDS
REACTION KINETICS
SYNTHESIS
550200* - Biochemistry
090900 - Biomass Fuels- Processing- (1990-)