title: Inhibitory kinetics of paeonol on the activity of mushroom tyrosinase oxidizing L-dopa.
abstract: 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.
authors.affiliation: College of Chemical Engineering and Energy, South China University of Technology, Guangzhou 510640, China. shengzhao2002@sina.com
authors.forename: Sheng-Zhao
authors.initials: SZ
authors.lastname: Gong
authors.forename: Jiang
authors.initials: J
authors.lastname: Cheng
authors.forename: Zhuo-Ru
authors.initials: ZR
authors.lastname: Yang
mesh_terms: 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
chemical_list: D000098:Acetophenones; D004791:Enzyme Inhibitors; C013638:paeonol; D007980:Levodopa; D014442:Monophenol Monooxygenase