Coenzyme A-acylating aldehyde dehydrogenase from Clostridium beijerinckii NRRL B592

Journal Article · Sat Sep 01 00:00:00 EDT 1990 · Applied and Environmental Microbiology; (USA)

OSTI ID:6420534

Yan, Run-Tao; Chen, Jiann-Shin ^[1]

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1. Virginia Polytechnic Institute and State Univ., Blacksburg (USA)

A coenzyme A (CoA)-acylating aldehyde dehydrogenase (ALDH), which also converts acyl-CoA to aldehyde and CoA, has been purified under anaerobic conditions from Clostridium beijerinckii NRRL B592. The ALDH showed a native molecular weight (M{sub r}) of 100,000 and a subunit M{sub r} of 55,000, suggesting that ALDH is dimeric. Purified ALDH contained no alcohol dehydrogenase activity. Activities measured with acetaldehyde and butyraldehyde as alternative substrates were copurified, indicating that the same ALDH can catalyze the formation of both aldehydes for ethanol and butanol production. Based on the K{sub m} and V{sub max} values for acetyl-CoA and butyryl-CoA, ALDH was more effective for the production of butyraldehyde than for acetaldehyde. ALDH could use either NAD(H) or NADP(H) as the coenzyme, but the K{sub m} for NAD(H) was much lower than that for NADP(H). Kinetic data suggest a ping-pong mechanism for the reaction. ALDH was more stable in Tris buffer than in phosphate buffer. The apparent optimum pH was between 6.5 and 7 for the forward reaction (the physiological direction; aldehyde forming), and it was 9.5 or higher for the reverse reaction (acyl-CoA forming). The ratio of NAD(H)/NADP(H)-linked activities increased with decreasing pH. ALDH was O{sub 2} sensitive, but it could be protected against O{sub 2} inactivation by dithiothreitol. The O{sub 2}-inactivated enzyme could be reactivated by incubating the enzyme with CoA in the presence or absence of dithiothreitol prior to assay.

• OSTI ID: 6420534
• Journal Information: Applied and Environmental Microbiology; (USA), Vol. 56:9; ISSN 0099-2240
• Country of Publication: United States
• Language: English

Related Subjects

09 BIOMASS FUELS
59 BASIC BIOLOGICAL SCIENCES
CLOSTRIDIUM
ENZYME ACTIVITY
ALDEHYDES
ANAEROBIC CONDITIONS
BIOSYNTHESIS
BUTANOLS
COENZYMES
ETHANOL
INACTIVATION
OXIDOREDUCTASES
OXYGEN
ALCOHOLS
BACTERIA
ELEMENTS
ENZYMES
HYDROXY COMPOUNDS
MICROORGANISMS
NONMETALS
ORGANIC COMPOUNDS
SYNTHESIS
090900* - Biomass Fuels- Processing- (1990-)
550200 - Biochemistry