Inhibitory kinetics of paeonol on the activity of mushroom tyrosinase oxidizing L-dopa / 药学学报

ABSTRACT

<p><b>AIM</b>To evaluate the effect of paeonol on the activity of tyrosinase and provide experimental evidence for the treatment of hyperpigmentation disorders.</p><p><b>METHODS</b>Tyrosinase activity was estimated by measuring the oxidation rate of L-3,4-dihydroxyphenylalanine (L-Dopa). The inhibitory effects of paeonol on the activity of mushroom tyrosinase and Michaelis-Menten kinetics were deduced from the Lineweaver-Burk plots.</p><p><b>RESULTS</b>The inhibitory concentration of paeonol leading to 50% enzyme activity lost (IC50) was estimated to be 0.60 mmol x L(-1). The inhibition constants for paeonol binding free enzyme, K(I), and substrate-enzyme, K(IS), are 0.084 and 0.12 mmol x L(-1), respectively.</p><p><b>CONCLUSION</b>Paeonol is a potential mixed inhibitor of mushroom tyrosinase. The mixed inhibition function may originate from its ability to form a Schiff base with a primary amino group and to chelate copper at the active site of tyrosinase.</p>