title: Kinetics of ergothioneine inhibition of mushroom tyrosinase.
abstract: The native amino acid ergothioneine, a thiourea derivative of histidine, inhibits mushroom tyrosinase activity in a dose-dependent manner, with an IC(50) value of 1.025 mg/ml (4.47 mM). By contrast, histidine exhibited no inhibitory effect on mushroom tyrosinase activity. We characterized ergothioneine as a noncompetitive tyrosinase inhibitor using a Lineweaver-Burk plot of experimental kinetic data. The IC(50) value for ergothioneine scavenging of 2,2-diphenyl-1-picrylhydrazyl was 6.110 ± 0.305 mg/ml, much higher than the IC(50) for inhibition of tyrosinase activity which indicating ergothioneine on tyrosinase shows a weak correlation to its antioxidative activity. The results demonstrated that ergothioneine has a potent inhibition effect on tyrosinase enzyme activity, resulting from the presence of the sulfur substituted imidazole ring in ergothioneine.
authors: Department of Nursing, Chang Gung Institution of Technology, Chia-Yi, Taiwan.
authors: Wayne C
authors: WC
authors: Liao
authors: Wen Hong
authors: WH
authors: Wu
authors: Pei-Chuan
authors: PC
authors: Tsai
authors: Hui-Feng
authors: HF
authors: Wang
authors: Yi-Hsin
authors: YH
authors: Liu
authors: Chin-Feng
authors: CF
authors: Chan
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D004880:Ergothioneine / Q000494:pharmacology*; D016166:Free Radical Scavengers / Q000494:pharmacology*; D006639:Histidine / Q000494:pharmacology; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D016166:Free Radical Scavengers; D006639:Histidine; D004880:Ergothioneine; D014442:Monophenol Monooxygenase