title: Determination of laccase activity in mixed solvents: comparison between two chromogens in a spectrophotometric assay.
abstract: Spectrophotometric determination of laccase activity with ABTS acting as chromogen yields exceedingly low values whenever conducted in a water-organic mixed solvent. Nevertheless, there is firm evidence that laccase is able to oxidize substrates such as phenols and amines quantitatively in these mixed solvents. We show that the apparently small rate of ABTS oxidation by laccase in a mixed solvent, such as buffered water-dioxane 1:1, is not amenable to the denaturation of laccase but rather to the decreased stability of ABTS(.+). We propose HAA as a more reliable chromogen for the determination of laccase activity in mixed solvents.
authors.affiliation: Dipartimento di Chimica and Centro CNR Meccanismi di Reazione, Università La Sapienza, 00185 Roma, Italy.
authors.forename: Gaetano
authors.initials: G
authors.lastname: Cantarella
authors.forename: Francesca
authors.initials: F
authors.lastname: d'Acunzo
authors.forename: Carlo
authors.initials: C
authors.lastname: Galli
mesh_terms: D015095:3-Hydroxyanthranilic Acid / Q000737:chemistry*; D052160:Benzothiazoles; D002863:Chromogenic Compounds / Q000737:chemistry*; D004789:Enzyme Activation; D042845:Laccase; D010088:Oxidoreductases / Q000737:chemistry*; D012996:Solutions / Q000737:chemistry; D012997:Solvents / Q000737:chemistry*; D013056:Spectrophotometry, Ultraviolet / Q000379:methods*; D013379:Substrate Specificity; D013451:Sulfonic Acids / Q000737:chemistry*; D014867:Water / Q000737:chemistry
chemical_list: D052160:Benzothiazoles; D002863:Chromogenic Compounds; D012996:Solutions; D012997:Solvents; D013451:Sulfonic Acids; D014867:Water; D015095:3-Hydroxyanthranilic Acid; C002502:2,2'-azino-di-(3-ethylbenzothiazoline)-6-sulfonic acid; D010088:Oxidoreductases; D042845:Laccase