ESR CHARACTERIZATION KINETICS OF THE ENZYMATICALLY OBTAINED M(II)-DOBUTAMINE-O-SEMIQUINONE SYSTEM

Dobutamine is a synthetic catecholamine used in the treatment of diffe rent cardiac pathologies associated with organic heart diseases, myoca rdial infarction and cardiac surgery. The ESR spectra of M(2+)-o-semiq uinone radicals, obtained by the oxidation of dobutamine . HCl with ho rseradish peroxidase and hydrogen peroxide in the presence of several bivalent metal ions of IIA (Mg, Ca, Sr, Ba) and IIB (Zn, Cd) groups, h ave been reported. ESR experimental spectra have been simulated and co mpletely characterized. The dependence of the proton hyperfine couplin g constant values on the complexing ion radius has been discussed toge ther with the differences in the radical concentrations. Furthermore, the formation and decay kinetics of Zn2+-dobutamine-o-semiquinone have been analyzed at varying H2O2 concentrations, and the corresponding k inetic constants have been calculated.