title: (S)-1-phenylethanol dehydrogenase of Azoarcus sp. strain EbN1, an enzyme of anaerobic ethylbenzene catabolism.
abstract: The initial steps in the anaerobic oxidation of the aromatic hydrocarbon ethylbenzene by denitrifying bacteria are two sequential dehydrogenation reactions of ethylbenzene to (S)-1-phenylethanol and further to acetophenone. The enzyme catalysing the second oxidation step, (S)-1-phenylethanol dehydrogenase, was analysed in the denitrifying bacterium Azoarcus sp. strain EbN1. An NAD+-dependent 1-phenylethanol dehydrogenase for each of the enantiomers of 1-phenylethanol was identified in this bacterium; the two enzymes were induced under different growth conditions. (S)-1-phenylethanol dehydrogenase from ethylbenzene-grown cells was purified and biochemically characterised. The enzyme is a typical secondary alcohol dehydrogenase and consists of two subunits of 25.5 kDa. The enantioselective enzyme catalyses the oxidation of (S)-1-phenylethanol or the reduction of acetophenone and is inhibited by high concentrations of (R)-1-phenylethanol. The enzyme exhibits low apparent K(m) values for (S)-1-phenylethanol and acetophenone and is rather substrate-specific, using only a few chemically similar secondary alcohols, such as 1-phenylpropanol and isopropanol.
authors.affiliation: Max Planck Institute for Marine Microbiology, Celsiusstrasse 1, 28359 Bremen, Germany.
authors.forename: O
authors.initials: O
authors.lastname: Kniemeyer
authors.forename: J
authors.initials: J
authors.lastname: Heider
mesh_terms: D019840:2-Propanol / Q000378:metabolism; D000595:Amino Acid Sequence; D000693:Anaerobiosis; D020627:Azoarcus / Q000201:enzymology* / Q000254:growth & development / Q000378:metabolism; D001555:Benzene Derivatives / Q000378:metabolism*; D002384:Catalysis; D007527:Isoenzymes / Q000037:antagonists & inhibitors / Q000302:isolation & purification / Q000378:metabolism; D007700:Kinetics; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D020005:Propanols / Q000378:metabolism; D021122:Protein Subunits; D016415:Sequence Alignment; D013379:Substrate Specificity
chemical_list: D001555:Benzene Derivatives; D007527:Isoenzymes; D020005:Propanols; D021122:Protein Subunits; D010088:Oxidoreductases; C121603:1-phenylethanol dehydrogenase; C004912:ethylbenzene; D019840:2-Propanol