An assay for pro-oxidant reactivity based on phenoxyl radicals generated by laccase.

A transient species may be detected with UV-vis and EPR spectroscopy during turnover of a laccase with quercetin; this species is assigned as a quercetin-derived radical, based on EPR spectra as well the observed UV-vis similarities (a 540nm centred band) with previously reported data. The rates of formation and decay of this species correlate well (r=0.9946) with the pro-oxidant reactivity manifested by flavonoids in the presence of laccase.