title: Irreversibly inhibitory kinetics of 3,5-dihydroxyphenyl decanoate on mushroom (Agaricus bisporus) tyrosinase.
abstract: 3,5-Dihydroxyphenyl decanoate (DPD) is found to inhibit the diphenolase activity of tyrosinase from mushroom (Agaricus bisporus). The effects of DPD on the diphenolase activity of mushroom tyrosinase have been studied. The results show that the enzyme activity decreases very slowly with an increase in DPD concentrations at lower concentrations of DPD (between 5 and 60 microM). But at higher concentrations of DPD, DPD can strongly inhibit the diphenolase activity of the enzyme and the inhibition is irreversible. The IC50 value was estimated to be 96.5 microM. The inhibition mechanism of DPD has been investigated and the results show that DPD can bind to the free enzyme molecule and enzyme-substrate complex and lose the enzyme activity completely. The inhibition kinetics has been studied in detail by using the kinetic method of the substrate reaction described by Tsou. The microscopic rate constants of the enzyme inhibited by DPD at higher concentrations have been determined.
authors.affiliation: Department of Biochemistry and Biotechnology, School of Life Sciences, The Key Laboratory of Ministry of Education for Cell Biology and Tumor Cell Engineering, Xiamen University, Xiamen, 361005, China.
authors.forename: Ling
authors.initials: L
authors.lastname: Qiu
authors.forename: Qing-Xi
authors.initials: QX
authors.lastname: Chen
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Hao
authors.initials: H
authors.lastname: Huang
authors.forename: Kang-Kang
authors.initials: KK
authors.lastname: Song
mesh_terms: D000364:Agaricus / Q000201:enzymology*; D003651:Decanoates / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*
chemical_list: C507094:3,5-dihydroxyphenyl decanoate; D003651:Decanoates; D014442:Monophenol Monooxygenase