title: Allylic or benzylic stabilization is essential for catalysis by bacterial benzyl alcohol dehydrogenases.
abstract: Benzyl alcohol dehydrogenase from Acinetobacter calcoaceticus (AC-BADH) and TOL plasmid-encoded benzyl alcohol dehydrogenase from Pseudomonas putida (TOL-BADH) have previously been shown to oxidize a variety of aromatic alcohols but not aliphatic substrates. Here, we have expressed the genes for AC-BADH and TOL-BADH in Escherichia coli, purified the resulting over-expressed enzymes, and shown that each is an effective catalyst of both benzylic and allylic alcohol oxidation, but not of oxidation of nonallylic analogs. Enzyme specificity (kcat/Km) for both enzymes was higher with an aliphatic, allylic alcohol (3-methyl-2-buten-1-ol) than with benzyl alcohol. These results suggest that bacterial benzyl alcohol dehydrogenases use the resonance stabilization provided by allylic and benzylic alcohols to promote catalysis.
authors.affiliation: Department of Chemistry and Biochemistry, University of Colorado, Boulder, Colorado, 80309-0215, USA.
authors.forename: A J
authors.initials: AJ
authors.lastname: Curtis
authors.forename: M C
authors.initials: MC
authors.lastname: Shirk
authors.forename: R
authors.initials: R
authors.lastname: Fall
mesh_terms: D016954:Acinetobacter calcoaceticus / Q000201:enzymology; D000429:Alcohol Oxidoreductases / Q000235:genetics / Q000378:metabolism*; D019905:Benzyl Alcohol / Q000378:metabolism; D002384:Catalysis; D007700:Kinetics; D015394:Molecular Structure; D010084:Oxidation-Reduction; D020005:Propanols / Q000378:metabolism; D016958:Pseudomonas putida / Q000201:enzymology; D011994:Recombinant Proteins / Q000235:genetics / Q000378:metabolism; D013379:Substrate Specificity
chemical_list: D020005:Propanols; D011994:Recombinant Proteins; C006463:allyl alcohol; D000429:Alcohol Oxidoreductases; C027016:benzyl alcohol dehydrogenase; D019905:Benzyl Alcohol