A new and sensitive catalytic resonance scattering spectral assay for the detection of laccase using guaiacol as substrate.

In pH 4.0 succinic acid-sodium hydroxide buffer solution, laccase catalyzed the oxidization of guaiacol substrate to form red particles, which exhibited a strong resonance scattering (RS) peak at 590 nm. Under the chosen conditions, as the laccase increased, the RS intensity (ΔI) increased linearly. The ΔI was proportional to laccase activity in the range of 0.10-1.2 U/mL, with a regression equation of ΔI = 734.0 U(laccase) - 9.7, and a detection limit of 0.05 U/mL. This RS method was applied to the detection of laccase activity in real samples, and the results were agreement with those from spectrophotometry.