title: The stoichiometry of tyrosinase-catalyzed oxidation of 4-hydroxyanisole.
abstract: Oxygen utilisation during tyrosinase-catalysed oxidation of 4-hydroxyanisole was investigated using an electron spin resonance technique which employs quantitative changes in the characteristics of the electron spin resonance spectrum of the spin label 3-carbamoyl-2,5-dihydro-2,2,5-5-tetramethyl-1-H-pyridoyl-1-ylox y (CTPO) to follow changes in the oxygen concentration. Reaction mixtures containing mushroom tyrosinase (15 micrograms ml-1) and differing initial concentrations of 4-hydroxyanisole in aerated phosphate buffer at pH 6.8 were incubated at room temperature. The ratio of utilisation of oxygen was found to be in approximately 1:1 molar ratio with the initial 4-hydroxyanisole concentration in the reaction mixture between 50 and 200 mumol/l 4-hydroxyanisole. The results are consistent with the stoichiometry of oxygen utilisation being accounted for by the oxidation of 4-hydroxyanisole to anisyl quinone.
authors.affiliation: Department of Biophysics, Jagiellonian University, Krakow, Poland.
authors.forename: J W
authors.initials: JW
authors.lastname: Dobrucki
authors.forename: P A
authors.initials: PA
authors.lastname: Riley
mesh_terms: D000840:Anisoles / Q000378:metabolism*; D004156:Catechol Oxidase / Q000378:metabolism*; D004578:Electron Spin Resonance Spectroscopy; D014442:Monophenol Monooxygenase / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*
chemical_list: D000840:Anisoles; C009760:mequinol; D004156:Catechol Oxidase; D014442:Monophenol Monooxygenase; D010100:Oxygen