Intermediary metabolism in Clostridium acetobutylicum: levels of enzymes involved in the formation of acetate and butyrate

Journal Article · Fri Jun 01 00:00:00 EDT 1984 · Appl. Environ. Microbiol.; (United States)

OSTI ID:5958589

Hartmanis, M G.N.; Gatenbeck, S

The levels of seven intermediary enzymes involved in acetate and butyrate formation from acetyl coenzyme A in the saccharolytic anaerobe Clostridium acetobutylicum were investigated as a function of time in solvent-producing batch fermentations. Phosphate acetyltransferase and acetate kinase, which are known to form acetate from acetyl coenzyme A, both showed a decrease in specific activity when the organism reached the solvent formation stage. The three consecutive enzymes thiolase, beta-hydroxybutyryl-coenzyme A dehydrogenase, and crotonase exhibited a coordinate expression and a maximal activity after growth had ceased. Only low levels of butyryl coenzyme A dehydrogenase activity were found. Phosphate butyryltransferase activity rapidly decreased after 20 h from 5 to 11 U/mg of protein to below the detection limit (1 mU/mg). Butyrate no longer can be formed, and the metabolic flux may be diverted to butanol. Butyrate kinase showed a 2.5- to 10-fold increase in specific activity after phosphate butyryltransferase activity no longer could be detected. These results suggest that the uptake of acetate and butyrate during solvent formation can not proceed via a complete reversal of the phosphate transferase and kinase reactions. The activities of all enzymes investigated as a function of time in vitro are much higher than the metabolic fluxes through them in vivo. This indicates that none of the maximal activities of the enzymes assayed is rate limiting in C. acetobutylicum. (Refs. 46).

• Research Organization: Royal Inst of Tech, S-100 44 Stockholm, Sweden Dept of Biochemistry and Biotech.
• OSTI ID: 5958589
• Journal Information: Appl. Environ. Microbiol.; (United States), Vol. 47:6
• Country of Publication: United States
• Language: English

Related Subjects

59 BASIC BIOLOGICAL SCIENCES
CLOSTRIDIUM ACETOBUTYLICUM
METABOLISM
ACETATES
BUTANOLS
BUTYRIC ACID
ENZYME ACTIVITY
FERMENTATION
IN VITRO
IN VIVO
METABOLITES
REACTION INTERMEDIATES
SOLVENTS
ALCOHOLS
BACTERIA
BIOCONVERSION
CARBOXYLIC ACID SALTS
CARBOXYLIC ACIDS
CLOSTRIDIUM
HYDROXY COMPOUNDS
METHANOGENIC BACTERIA
MICROORGANISMS
MONOCARBOXYLIC ACIDS
ORGANIC ACIDS
ORGANIC COMPOUNDS
550700* - Microbiology