title: EPR and LC-MS studies on the mechanism of industrial dye decolorization by versatile peroxidase from Bjerkandera adusta.
abstract: The mechanisms of industrial dye transformation by versatile peroxidase were elucidated. Purified versatile peroxidase from Bjerkandera adusta was able to decolorize different classes of dyes including azo and phthalocyanines, but unable to transform any of the anthraquinones tested. Kinetic constants for selected dyes were determined and the transformation products were analyzed by EPR spectroscopy and mass spectrometry. The EPR and MS analyses of the enzymatic decolorization products showed the cleavage of the azo bond in azo dyes and the total disruption of the phthalocyaninic ring in phthalocyanine dyes. The EPR analysis on two copper-containing dyes, reactive violet 5 (azo) and reactive blue 72 (phthalocyanine), showed that the transformation can or not break the metal-ion coordination bond according the dye nature. The role of the catalytic Trp172 in the dye transformation by a long-range electron transfer pathway was confirmed and the oxidation mechanisms are proposed and discussed.
authors.affiliation: Department of Biotechnology, Chemistry, and Pharmacy, University of Siena, Siena, Italy.
authors.forename: Maria Camilla
authors.initials: MC
authors.lastname: Baratto
authors.forename: Karla
authors.initials: K
authors.lastname: Juarez-Moreno
authors.forename: Rebecca
authors.initials: R
authors.lastname: Pogni
authors.forename: Riccardo
authors.initials: R
authors.lastname: Basosi
authors.forename: Rafael
authors.initials: R
authors.lastname: Vazquez-Duhalt
mesh_terms: D000880:Anthraquinones / Q000737:chemistry; D001391:Azo Compounds / Q000737:chemistry*; D002384:Catalysis; D002853:Chromatography, Liquid; D004396:Coloring Agents / Q000737:chemistry*; D055453:Coriolaceae / Q000201:enzymology*; D007211:Indoles / Q000737:chemistry*; D054833:Isoindoles; D007700:Kinetics; D013058:Mass Spectrometry; D009282:Naphthalenesulfonates / Q000737:chemistry; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000737:chemistry* / Q000378:metabolism; D014874:Water Pollutants, Chemical / Q000737:chemistry*; D018508:Water Purification / Q000379:methods
chemical_list: D000880:Anthraquinones; D001391:Azo Compounds; D004396:Coloring Agents; D007211:Indoles; D054833:Isoindoles; D009282:Naphthalenesulfonates; D014874:Water Pollutants, Chemical; C111247:C.I. Reactive Violet 5; D010544:Peroxidases; C063421:Remazol black B; C013647:phthalocyanine