title: The mediation of veratryl alcohol in oxidations promoted by lignin peroxidase: the lifetime of veratryl alcohol radical cation.
abstract: The kinetics of decay of veratryl alcohol radical cation, generated by cerium(IV) ammonium nitrate induced oxidation of veratryl alcohol, have been followed spectrophotometrically in a stopped-flow apparatus. In acidic aqueous acetonitrile the radical cation was found to decay by a first-order process, due to deprotonation from the alpha-carbon leading to an alpha-hydroxybenzyl radical with the rate constant of 17.1+/-0.5 s(-1). This value is in full agreement with those obtained by pulse radiolysis studies but much lower than the value (1.2x10(3) s(-1)) indirectly determined by EPR experiments. The implications of these results with respect to the possible role of veratryl alcohol as a mediator in the oxidative biodegradation of lignin catalysed by lignin peroxidase are discussed.
authors.affiliation: Dipartimento di Chimica, Università La Sapienza, P.le A. Moro, 5 I-00185 Rome, Italy. baciocchi@uniroma1.it
authors.forename: Enrico
authors.initials: E
authors.lastname: Baciocchi
authors.forename: Massimo
authors.initials: M
authors.lastname: Bietti
authors.forename: Maria Francesca
authors.initials: MF
authors.lastname: Gerini
authors.forename: Osvaldo
authors.initials: O
authors.lastname: Lanzalunga
mesh_terms: D001592:Benzyl Alcohols / Q000737:chemistry*; D002412:Cations; D007700:Kinetics; D008031:Lignin / Q000378:metabolism; D008956:Models, Chemical; D010084:Oxidation-Reduction; D010544:Peroxidases / Q000378:metabolism*
chemical_list: D001592:Benzyl Alcohols; D002412:Cations; D008031:Lignin; D010544:Peroxidases; C042858:lignin peroxidase; C042197:veratryl alcohol