Figure 1. Progress curves for the inhibition of monophenolase of mushroom tyrosinase by α-arbutin at 30°C.

The reaction media (3.0 mL) contained 0.5 mM L-tyrosine in 50 mM phosphate buffer (pH 6.8), the indicated concentration of α-arbutin, and mushroom tyrosinase (20 µg/mL). The concentrations of α-arbutin for curves 1∼4 were 0, 1.67, 3.34, 4.18 mmol·L⁻¹. The reaction was started by the addition of the enzyme.