title: Substrate and inhibitor spectra of ethylbenzene dehydrogenase: perspectives on application potential and catalytic mechanism.
abstract: Ethylbenzene dehydrogenase (EbDH) catalyzes the initial step in anaerobic degradation of ethylbenzene in denitrifying bacteria, namely, the oxygen-independent hydroxylation of ethylbenzene to (S)-1-phenylethanol. In our study we investigate the kinetic properties of 46 substrate analogs acting as substrates or inhibitors of the enzyme. The apparent kinetic parameters of these compounds give important insights into the function of the enzyme and are consistent with the predicted catalytic mechanism based on a quantum chemical calculation model. In particular, the existence of the proposed substrate-derived radical and carbocation intermediates is substantiated by the formation of alternative dehydrogenated and hydroxylated products from some substrates, which can be regarded as mechanistic models. In addition, these results also show the surprisingly high diversity of EbDH in hydroxylating different kinds of alkylaromatic and heterocyclic compounds to the respective alcohols. This may lead to attractive industrial applications of ethylbenzene dehydrogenase for a new process of producing alcohols via hydroxylation of the corresponding aromatic hydrocarbons rather than the customary procedure of reducing the corresponding ketones.
authors: Laboratory for Microbial Biochemistry, Philipps University of Marburg, Marburg, Germany.
authors: Daniel
authors: D
authors: Knack
authors: Corina
authors: C
authors: Hagel
authors: Maciej
authors: M
authors: Szaleniec
authors: Agnieszka
authors: A
authors: Dudzik
authors: Aleksander
authors: A
authors: Salwinski
authors: Johann
authors: J
authors: Heider
mesh_terms: D001419:Bacteria / Q000201:enzymology*; D001555:Benzene Derivatives / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000378:metabolism*; D007700:Kinetics; D010088:Oxidoreductases / Q000737:chemistry / Q000378:metabolism*; D010626:Phenylethyl Alcohol / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D001555:Benzene Derivatives; D004791:Enzyme Inhibitors; D010088:Oxidoreductases; C121602:ethylbenzene dehydrogenase; C004912:ethylbenzene; D010626:Phenylethyl Alcohol