Inhibitory kinetics of paeonol on the activity of mushroom tyrosinase oxidizing L-dopa.
OBJECTIVE
To evaluate the effect of paeonol on the activity of tyrosinase and provide experimental evidence for the treatment of hyperpigmentation disorders.


METHODS
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.


RESULTS
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.


CONCLUSIONS
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.
Gong
Sheng-Zhao
SZ
College of Chemical Engineering and Energy, South China University of Technology, Guangzhou 510640, China. shengzhao2002@sina.com
Cheng
Jiang
J
Yang
Zhuo-Ru
ZR
D000098:Acetophenones / Q000302:isolation & purification / Q000494:pharmacology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D007700:Kinetics; D007980:Levodopa / Q000378:metabolism; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D029596:Paeonia / Q000737:chemistry; D010946:Plants, Medicinal / Q000737:chemistry
D000098:Acetophenones; D004791:Enzyme Inhibitors; C013638:paeonol; D007980:Levodopa; D014442:Monophenol Monooxygenase