title: Purification, biochemical properties and substrate specificity of a catechol 1,2-dioxygenase from a phenol degrading Acinetobacter radioresistens.
abstract: A catechol 1,2-dioxygenase (C1,2O) has been purified to homogeneity from Acinetobacter radioresistens grown on phenol as the sole carbon and energy source. The C1,2O appears to be a homodimer, with a molecular mass of 78,000 Da. At relatively high ionic strengths (0.5 M Na2SO4) subunit dissociation occurs and the monomeric unit (38,700 Da) is shown to be active. This phenomenon has never been observed before in dioxygenases. The purified C1,2O contains 0.96 iron(III) ions per unit and spectroscopic measurements suggest the presence of one high-spin iron(III) ion in an environment characteristic of intradiol cleaving enzymes. The NH2-terminal amino acid sequence has been determined and compared to the primary structures of intradiol rings cleaving dioxygenases from other Acinetobacter strains revealing 45% homology with the benzoate-grown A. calcoaceticus ADP-1 and an identity of only one of the 20 amino acids sequenced for the phenol-grown A. calcoaceticus NCIB 8250.
authors.affiliation: Dipartimento di Chimica, Università degli Studi di Firenze, Florence, Italy.
authors.forename: F
authors.initials: F
authors.lastname: Briganti
authors.forename: E
authors.initials: E
authors.lastname: Pessione
authors.forename: C
authors.initials: C
authors.lastname: Giunta
authors.forename: A
authors.initials: A
authors.lastname: Scozzafava
mesh_terms: D000150:Acinetobacter / Q000201:enzymology*; D000595:Amino Acid Sequence; D050548:Catechol 1,2-Dioxygenase; D002851:Chromatography, High Pressure Liquid; D002852:Chromatography, Ion Exchange; D049308:Dioxygenases; D004578:Electron Spin Resonance Spectroscopy; D004591:Electrophoresis, Polyacrylamide Gel; D006863:Hydrogen-Ion Concentration; D006868:Hydrolysis; D007526:Isoelectric Point; D008969:Molecular Sequence Data; D010105:Oxygenases / Q000737:chemistry / Q000302:isolation & purification* / Q000378:metabolism; D010636:Phenols / Q000378:metabolism*; D017386:Sequence Homology, Amino Acid; D013379:Substrate Specificity; D013696:Temperature
chemical_list: D010636:Phenols; D010105:Oxygenases; D049308:Dioxygenases; D050548:Catechol 1,2-Dioxygenase