HORSERADISH-PEROXIDASE CATALYZED HYDROXYLATION OF PHENOL .2. KINETIC-MODEL

A numeric kinetic model of the horseradish peroxidase catalyzed hydrox ylation of phenol is proposed to complete the previous thermodynamic a nalysis. As previously stated, the basic role of HRP is to catalyze th e production of DHF. radicals. These further form hydroxyl radicals th at hydroxylate phenol via noncatalyzed reactions. The transient differ ential equations of the model are solved numerically. Several kinetic constants are adjusted to fit basic experimental data. This set of val ues is then kept constant to simulate additive experiments carried out under different conditions. Predictions of the model concerning the e ffects of HRP concentration, temperature variation, and presence of ca talase and superoxide dismutase are consistent with the experimental r esults. The quantitative kinetic approach consequently fully confirmed the previous thermodynamic conclusions.