title: Molecular characterization of a novel arylesterase from the wine-associated acetic acid bacterium Gluconobacter oxidans 621H.
abstract: An arylesterase from the wine-making acetic acid bacterium, Gluconobacter oxidans, was cloned and expressed into Escherichia coli. The soluble 76.8 kDa dimeric enzyme obtained, Est0881, was purified in only two steps with a 3.1-fold purification, 43% recovery, and a specific activity of 214 U/mg for the hydrolysis of p-nitrophenyl acetate. The optimum pH and temperature were 7.0 and 40 °C, respectively. The substrate specificity of this arylesterase was higher toward short chain p-nitrophenyl esters (C(2) to C(4)) and also toward aromatic esters, such as phenyl acetate. The deduced amino acid sequence shares high identity with esterases of the HSL family. The inhibition results obtained showed that the enzyme was a serine esterase, belonging to the A-esterases (arylesterases) and contains a catalytic triad composed of Ser163, Asp263, and His293 in the active site. Est0881 retained significant activity under conditions simulating those of wine-making (75% activity at 20% ethanol), making it a promising biocatalyst for modulating the final aroma of wine.
authors.affiliation: Faculty of Biology, Department of Biochemistry and Molecular Biology-A, University of Murcia, Campus Espinardo, E-30100 Murcia, Spain.
authors.forename: Inmaculada
authors.initials: I
authors.lastname: Navarro-González
authors.forename: Álvaro
authors.initials: Á
authors.lastname: Sánchez-Ferrer
authors.forename: Francisco
authors.initials: F
authors.lastname: García-Carmona
mesh_terms: D019342:Acetic Acid / Q000378:metabolism; D000595:Amino Acid Sequence; D001426:Bacterial Proteins / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D002265:Carboxylic Ester Hydrolases / Q000737:chemistry / Q000235:genetics* / Q000302:isolation & purification / Q000378:metabolism; D020576:Gluconobacter / Q000737:chemistry / Q000201:enzymology* / Q000235:genetics / Q000302:isolation & purification; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D008969:Molecular Sequence Data; D016415:Sequence Alignment; D013379:Substrate Specificity; D013696:Temperature; D014920:Wine / Q000382:microbiology*
chemical_list: D001426:Bacterial Proteins; D002265:Carboxylic Ester Hydrolases; C019734:arylesterase; D019342:Acetic Acid