Horseradish Peroxidase. XVIII. The Arrhenius Activation Energy for the Formation of Compound I

Abstract

The rate of formation of compound I from the reaction of native horseradish peroxidase with hydrogen peroxide was studied from 3.7–70.0 °C. The second-order rate constants were used to construct an Arrhenius plot from which the activation energy of this reaction was calculated to be 3.5 ± 1.0 kcal/mol. The irreversibility of the reaction at 25 °C was confirmed by comparing absolute absorbance changes as recorded by the stopped-flow apparatus with the known spectra of the native enzyme and compound I.