title: Inhibitory effects of fluorobenzaldehydes on the activity of mushroom tyrosinase.
abstract: The effects of fluorobenzaldehydes (2-,3- and 4-fluorobenzaldehyde) on the activity of mushroom tyrosinase have been studied. The results show that fluorobenzaldehydes can strongly inhibit both monophenolase activity and diphenolase activity of the enzyme and the inhibition is reversible. The IC50 values were estimated as 1.62 mM, 1.06 mM and 0.16 mM for diphenolase activity and as 1.35 mM, 1.18 mM and 1.05 mM for monophenolase activity, respectively. The lag time of the monophenolase was obviously lengthened by these three fluorobenzaldehydes. When the concentration of inhibitors reached 2.0 mM, the lag time was lengthened from 33 s to 142 s, 168 s and 190 s, respectively. Kinetic analyses show that the inhibition mechanism of 2-fluorobenzaldehyde on the diphenolase was competitive inhibition of the diphenolase activity, and that of 3-fluorobenzaldehyde and 4-fluorobenzaldehyde were of a mixed-type. The inhibition constants for these three fluorobenzaldehydes on the diphenolase were determined and compared.
authors.affiliation: Key Laboratory of Biopesticide and Chemical Biology, Fujian Agriculture and Forestry University, Ministry of Education, Fuzhou 350002, PR China.
authors.forename: Xiao-Hong
authors.initials: XH
authors.lastname: Huang
authors.forename: Qing-Xi
authors.initials: QX
authors.lastname: Chen
authors.forename: Min-Sheng
authors.initials: MS
authors.lastname: You
authors.forename: Qin
authors.initials: Q
authors.lastname: Wang
authors.forename: Kang-Kang
authors.initials: KK
authors.lastname: Song
authors.forename: Jun
authors.initials: J
authors.lastname: Wang
authors.forename: Li
authors.initials: L
authors.lastname: Sha
authors.forename: Xiong
authors.initials: X
authors.lastname: Guan
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D001547:Benzaldehydes / Q000737:chemistry / Q000494:pharmacology*; D002384:Catalysis; D002626:Chemistry, Pharmaceutical / Q000379:methods; D004305:Dose-Response Relationship, Drug; D015195:Drug Design; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D020128:Inhibitory Concentration 50; D007700:Kinetics; D008956:Models, Chemical; D014442:Monophenol Monooxygenase / Q000737:chemistry; D010088:Oxidoreductases / Q000737:chemistry; D013997:Time Factors
chemical_list: D001547:Benzaldehydes; D004791:Enzyme Inhibitors; D010088:Oxidoreductases; C412191:monophenolase; D014442:Monophenol Monooxygenase