title: Mushroom tyrosinase inhibition by two potent uncompetitive inhibitors.
abstract: Two new bi-pyridine compounds, [1,4'] Bipiperidinyl-1'-yl-naphthan-2-yl-methanone (I) and [1,4'] Bipiperidinyl-1'-yl-4-methylphenyl-methane (II) were synthesized and examined for inhibition of the catecholase activity of mushroom tyrosinase in 10 mM phosphate buffer pH 6.8, at 293 K using UV spectrophotometry. Inhibition kinetics indicated that they were uncompetitive inhibitors and the value of the inhibition constants were 5.87 and 1.31 microM for I and II, respectively, which showed high potency. Fluorescent studies confirmed the uncompetitive type of inhibition for these two inhibitors. The inhibition mechanism presumably comes from the presence of a particular hydrophobe site which can accommodate these inhibitors. This site could be formed due to a probable conformational change that was induced by binding of substrate with the enzyme.
authors.affiliation: Institute of Biochemistry and Biophysics, University of Tehran, Tehran, Iran.
authors.forename: F
authors.initials: F
authors.lastname: Karbassi
authors.forename: A A
authors.initials: AA
authors.lastname: Saboury
authors.forename: M T Hassan
authors.initials: MT
authors.lastname: Khan
authors.forename: M Iqbal
authors.initials: MI
authors.lastname: Choudhary
authors.forename: Z S
authors.initials: ZS
authors.lastname: Saifi
mesh_terms: D000363:Agaricales / Q000201:enzymology*; D001667:Binding, Competitive; D004791:Enzyme Inhibitors / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*; D015394:Molecular Structure; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000737:chemistry; D011725:Pyridines / Q000138:chemical synthesis / Q000737:chemistry / Q000494:pharmacology*
chemical_list: D004791:Enzyme Inhibitors; D011725:Pyridines; D014442:Monophenol Monooxygenase