title: In vitro effect of ozagrel on mushroom tyrosinase.
abstract: This investigation, in vitro, shows that ozagrel, an antithrombotic drug, inhibited both monophenolase and diphenolase activities of mushroom tyrosinase when L: -tyrosine and L: -DOPA were assayed spectrophotometrically, respectively. The IC(50) values, for monophenolase and diphenolase activities, were 1.35 and 3.45 mM, respectively. Ozagrel was estimated to be a reversible mixed-type inhibitor of diphenolase activity with the constants (K (S1), K (S2), K (i1), and K (i2)) determined to be 2.21, 3.89, 0.454, and 0.799 mM, repectively. Increasing ozagrel concentrations provoked longer lag periods as well as a concomitant decrease in the monophenolase activity. Inhibition experiment demonstrated that ozagrel bound the enzyme at a site distincted from the substrate active site, but it bound to either E (Enzyme) or ES (Enzyme-Substrate) complex.
authors.affiliation: College of Chemistry, Chemical Engineering and Biotechnology, Donghua University, 201620 Shanghai, China.
authors.forename: Shu-Bai
authors.initials: SB
authors.lastname: Li
authors.forename: Yong
authors.initials: Y
authors.lastname: Xue
authors.forename: Xin-Yu
authors.initials: XY
authors.lastname: Lv
authors.forename: Hua-Li
authors.initials: HL
authors.lastname: Nie
authors.forename: Li-Min
authors.initials: LM
authors.lastname: Zhu
authors.forename: Hai-Tao
authors.initials: HT
authors.lastname: Zhang
authors.forename: Tao
authors.initials: T
authors.lastname: Qiu
authors.forename: Li-Ming
authors.initials: LM
authors.lastname: Zhou
mesh_terms: D000363:Agaricales / Q000187:drug effects / Q000201:enzymology*; D004156:Catechol Oxidase / Q000037:antagonists & inhibitors / Q000378:metabolism; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D007980:Levodopa / Q000378:metabolism; D016014:Linear Models; D008689:Methacrylates / Q000494:pharmacology*; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors*; D010088:Oxidoreductases / Q000037:antagonists & inhibitors / Q000378:metabolism; D014443:Tyrosine / Q000378:metabolism
chemical_list: D004791:Enzyme Inhibitors; D008689:Methacrylates; D014443:Tyrosine; D007980:Levodopa; D010088:Oxidoreductases; D004156:Catechol Oxidase; C412191:monophenolase; D014442:Monophenol Monooxygenase; C034364:ozagrel