title: Effects of tyramine and 4-aminophenol on the oscillating peroxidase-oxidase reaction.
abstract: The peroxidase-oxidase oscillator, a model of biological oscillations, is usually studied in conjunction with the effector molecule, 2,4-dichlorophenol. In this account, we present evidence of the effects of a naturally occurring phenol, tyramine, on the reaction, and also those of the structurally similar 4-aminophenol. Whereas 2,4-dichlorophenol gives rise to sustained oscillations at 40 μM, it was discovered that tyramine promotes damped oscillations at a concentration of 120 μM. Oxidation of NADH was completely inhibited by 4-aminophenol and ascorbate. In separate experiments, the peroxidase-catalyzed ring coupling of tyramine and 4-aminophenol was observed, which in the case of tyramine, may provide an explanation for the damping of oscillations.
authors.affiliation: School of Biochemistry and Immunology, Trinity College , Dublin 2, Ireland.
authors.forename: Andrew G
authors.initials: AG
authors.lastname: McDonald
authors.forename: Keith F
authors.initials: KF
authors.lastname: Tipton
mesh_terms: D000627:Aminophenols / Q000494:pharmacology*; D055162:Biocatalysis / Q000187:drug effects; D010088:Oxidoreductases / Q000378:metabolism*; D009195:Peroxidase / Q000378:metabolism*; D014439:Tyramine / Q000494:pharmacology*
chemical_list: D000627:Aminophenols; D010088:Oxidoreductases; D009195:Peroxidase; C026729:4-aminophenol; D014439:Tyramine