title: The phenylthiourea is a competitive inhibitor of the enzymatic oxidation of DOPA by phenoloxidase.
abstract: Phenoloxidase is a key enzyme of melanization catalyzing the oxidation of phenols. Phenylthiourea (PTU) is the well-known and widely used inhibitor of phenoloxidase. However, the mechanism of its action is not quite clear. In the present work, the effect of PTU on the enzymatic oxidation of 3-(3,4-dihydroxyphenyl)-l-alanine (DOPA) by phenoloxidase was studied by spectrophotometric methods. The inhibition constant of PTU was estimated as 0.21 ± 0.09 µM and the competitive type of inhibition was determined for this reaction.
authors.affiliation: Institute of Chemical Kinetics and Combustion, Laboratory of Chemistry and Physics of Free Radicals, Institutskaya 3, Novosibirsk, Russian Federation. razanova@kinetics.nsc.ru
authors.forename: Alexandra D
authors.initials: AD
authors.lastname: Ryazanova
authors.forename: Alexander A
authors.initials: AA
authors.lastname: Alekseev
authors.forename: Irina A
authors.initials: IA
authors.lastname: Slepneva
mesh_terms: D055162:Biocatalysis; D004295:Dihydroxyphenylalanine / Q000737:chemistry / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D004791:Enzyme Inhibitors / Q000737:chemistry / Q000494:pharmacology*; D014442:Monophenol Monooxygenase / Q000037:antagonists & inhibitors* / Q000378:metabolism; D010084:Oxidation-Reduction; D010670:Phenylthiourea / Q000737:chemistry / Q000494:pharmacology*; D013329:Structure-Activity Relationship
chemical_list: D004791:Enzyme Inhibitors; D004295:Dihydroxyphenylalanine; D010670:Phenylthiourea; D014442:Monophenol Monooxygenase