title: Hydrogen peroxide helps in the identification of monophenols as possible substrates of tyrosinase.
abstract: Tyrosinase exists in three forms in the catalytic cycle depending on the oxidation state of the copper: met- (Em), oxy- (E(ox)), and deoxy- (Ed). When O-quinones, products of the enzymatic reaction, evolve chemically to generate an O-diphenol in the reaction medium, the enzyme acts on a monophenol with O-diphenol as reductant, converting Em to Ed. The binding of Ed to molecular oxygen gives E(ox), which is active on monophenols, but when the O-quinone product does not generate O-diphenol through chemical evolution, the monophenol does not act as an enzyme substrate. The fact that E(ox) can be formed from Em with hydrogen peroxide can be used to help identify whether a monophenol is a substrate of tyrosinase. The results obtained in this study confirm that compounds previously described as inhibitors of the enzyme are true substrates of it.
authors: GENZ: Investigation Group of Enzimology, Department of Biochemistry and Molecular Biology A. Faculty of Biology, Regional Campus of International Excellence ``Campus Mare Nostrum'', University of Murcia.
authors: Mary of the Sea
authors: Mo
authors: García-Molina
authors: Joseph Luis
authors: JL
authors: Muñoz-Muñoz
authors: Joseph
authors: J
authors: Berna
authors: Joseph Neptune
authors: JN
authors: Rodríguez-López
authors: Ramón
authors: R
authors: Varón
authors: Francis
authors: F
authors: García-Cánovas
mesh_terms: D000363:Agaricales / Q000201:enzymology; D004791:Enzyme Inhibitors / Q000378:metabolism*; D006861:Hydrogen Peroxide / Q000378:metabolism*; D006900:Hydroxylation; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors / Q000378:metabolism*; D010084:Oxidation-Reduction; D010636:Phenols / Q000378:metabolism*; D011485:Protein Binding; D013379:Substrate Specificity
chemical_list: D004791:Enzyme Inhibitors; D010636:Phenols; D006861:Hydrogen Peroxide; D014442:Monophenol Monooxygenase