title: Melatonin activates the peroxidase-oxidase reaction and promotes oscillations.
abstract: We have studied the peroxidase-oxidase reaction with NADH and O2 as substrates and melatonin as a cofactor in a semibatch reactor. We show for the first time that melatonin is an activator of the reaction catalyzed by enzymes from both plant and animal sources. Furthermore, melatonin promotes oscillatory dynamics in the pH range from 5 to 6. The frequency of the oscillations depends on the pH such that an increase in pH was accompanied by a decrease in frequency. Conversely, an increase in the flow rate of NADH or an increase in the average concentration of NADH resulted in an increase in oscillation frequency. Complex dynamics were not observed with melatonin as a cofactor. These results are discussed in relation to observations of oscillatory dynamics and the function of melatonin and peroxidase in activated neutrophils.
authors: Celcom, Department of Biochemistry and Molecular Biology, SDU Odense University, Campusvej 55, Odense M, DK-5230, Denmark. lfo@dou.dk
authors: L F
authors: LF
authors: Olsen
authors: A
authors: A
authors: Lunding
authors: F R
authors: FR
authors: Lauritsen
authors: M
authors: M
authors: Allegra
mesh_terms: D000818:Animals; D002384:Catalysis; D002417:Cattle; D006735:Horseradish Peroxidase / Q000378:metabolism; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D007784:Lactoperoxidase / Q000378:metabolism; D008550:Melatonin / Q000378:metabolism / Q000494:pharmacology*; D008892:Milk / Q000201:enzymology; D008956:Models, Chemical; D009243:NAD / Q000378:metabolism*; D009991:Oscillometry; D010088:Oxidoreductases / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D010544:Peroxidases / Q000378:metabolism*; D013025:Glycine max / Q000201:enzymology
chemical_list: D009243:NAD; D010088:Oxidoreductases; D006735:Horseradish Peroxidase; D007784:Lactoperoxidase; D010544:Peroxidases; D008550:Melatonin; D010100:Oxygen