title: Biochemical characterization of a bifunctional acetaldehyde-alcohol dehydrogenase purified from a facultative anaerobic bacterium Citrobacter sp. S-77.
abstract: Acetaldehyde-alcohol dehydrogenase (ADHE) is a bifunctional enzyme consisting of two domains of an N-terminal acetaldehyde dehydrogenase (ALDH) and a C-terminal alcohol dehydrogenase (ADH). The enzyme is known to be important in the cellular alcohol metabolism. However, the role of coenzyme A-acylating ADHE responsible for ethanol production from acetyl-CoA remains uncertain. Here, we present the purification and biochemical characterization of an ADHE from Citrobacter sp. S-77 (ADHE(S77)). Interestingly, the ADHE(S77) was unable to be solubilized from membrane with detergents either 1% Triton X-100 or 1% Sulfobetaine 3-12. However, the enzyme was easily dissociated from membrane by high-salt buffers containing either 1.0 M NaCl or (NH(4))(2)SO(4) without detergents. The molecular weight of a native protein was estimated as approximately 400 kDa, consisting of four identical subunits of 96.3 kDa. Based on the specific activity and kinetic analysis, the ADHES77 tended to have catalytic reaction towards acetaldehyde elimination rather than acetaldehyde formation. Our experimental observation suggests that the ADHES77 may play a pivotal role in modulating intracellular acetaldehyde concentration.
authors.affiliation: International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan; Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Kohsei
authors.initials: K
authors.lastname: Tsuji
authors.affiliation: International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan; Centre for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan.
authors.forename: Ki-Seok
authors.initials: KS
authors.lastname: Yoon
authors.affiliation: International Institute for Carbon-Neutral Energy Research (WPI-I2CNER), Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan; Department of Chemistry and Biochemistry, Graduate School of Engineering, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan; Centre for Small Molecule Energy, Kyushu University, 744 Moto-oka, Nishi-ku, Fukuoka 819-0395, Japan. Electronic address: ogotcm@mail.cstm.kyushu-u.ac.jp.
authors.forename: Seiji
authors.initials: S
authors.lastname: Ogo
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism; D000105:Acetyl Coenzyme A / Q000378:metabolism; D000215:Acylation; D000426:Alcohol Dehydrogenase / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D000438:Alcohols / Q000378:metabolism; D000445:Aldehyde Oxidoreductases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D000693:Anaerobiosis; D001622:Betaine / Q000031:analogs & derivatives; D055162:Biocatalysis; D002954:Citrobacter / Q000201:enzymology*; D003065:Coenzyme A / Q000378:metabolism; D003902:Detergents; D007700:Kinetics; D008970:Molecular Weight; D064251:Multifunctional Enzymes / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism*; D017830:Octoxynol; D021122:Protein Subunits; D012995:Solubility
chemical_list: D000438:Alcohols; D003902:Detergents; D064251:Multifunctional Enzymes; D021122:Protein Subunits; D001622:Betaine; D000105:Acetyl Coenzyme A; C483727:sulfobetaine; D017830:Octoxynol; D000426:Alcohol Dehydrogenase; D000445:Aldehyde Oxidoreductases; C018699:aldehyde dehydrogenase (NAD(P)+); D000079:Acetaldehyde; D003065:Coenzyme A
keywords: Acetaldehyde-alcohol dehydrogenase; Alcohol dehydrogenase; Alcohol metabolism; Aldehyde dehydrogenase; Citrobacter sp. S-77; Coenzyme A-acylating; Kinetic parameters; Specific activity