title: Characterization of alcohol dehydrogenase from the haloalkaliphilic archaeon Natronomonas pharaonis.
abstract: Alcohol dehydrogenase (ADH; EC: 1.1.1.1) is a key enzyme in production and utilization of ethanol. In this study, the gene encoding for ADH of the haloalkaliphilic archaeon Natronomonas pharaonis (NpADH), which has a 1,068-bp open reading frame that encodes a protein of 355 amino acids, was cloned into the pET28b vector and was expressed in Escherichia coli. Then, NpADH was purified by Ni-NTA affinity chromatography. The recombinant enzyme showed a molecular mass of 41.3 kDa by SDS-PAGE. The enzyme was haloalkaliphilic and thermophilic, being most active at 5 M NaCl or 4 M KCl and 70 degrees C, respectively. The optimal pH was 9.0. Zn2+ significantly inhibited activity. The Km value for acetaldehyde was higher than that for ethanol. It was concluded that the physiological role of this enzyme is likely the catalysis of the oxidation of ethanol to acetaldehyde.
authors.affiliation: College of Life Sciences, Zhejiang University, Hangzhou 310058, People's Republic of China.
authors.forename: Yi
authors.initials: Y
authors.lastname: Cao
authors.forename: Li
authors.initials: L
authors.lastname: Liao
authors.forename: Xue-wei
authors.initials: XW
authors.lastname: Xu
authors.forename: Aharon
authors.initials: A
authors.lastname: Oren
authors.forename: Ce
authors.initials: C
authors.lastname: Wang
authors.forename: Xu-feng
authors.initials: XF
authors.lastname: Zhu
authors.forename: Min
authors.initials: M
authors.lastname: Wu
mesh_terms: D000079:Acetaldehyde / Q000378:metabolism; D000426:Alcohol Dehydrogenase / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D019843:Archaeal Proteins / Q000235:genetics / Q000302:isolation & purification / Q000378:metabolism*; D003001:Cloning, Molecular; D004795:Enzyme Stability; D000431:Ethanol / Q000378:metabolism*; D006216:Halobacteriaceae / Q000201:enzymology* / Q000235:genetics; D006863:Hydrogen-Ion Concentration; D008970:Molecular Weight; D010802:Phylogeny; D011189:Potassium Chloride / Q000378:metabolism; D011489:Protein Denaturation; D011994:Recombinant Proteins / Q000378:metabolism; D012965:Sodium Chloride / Q000378:metabolism; D013696:Temperature; D015032:Zinc / Q000378:metabolism
chemical_list: D019843:Archaeal Proteins; D011994:Recombinant Proteins; D000431:Ethanol; D012965:Sodium Chloride; D011189:Potassium Chloride; D000426:Alcohol Dehydrogenase; D000079:Acetaldehyde; D015032:Zinc