Kinetics of Irreversible Thermal Denaturation of Horseradish Peroxidase

Horseradish peroxidase (HRP) isolated from roots of horseradish was purified by a combination of ammonium sulfate, ion-exchange and gel filtration. The specific activity of the purified enzyme was 14.92 fold higher than the crude extract. Purified HRP was then used for kinetic and thermodynamic characterization. Irreversible thermal denaturation followed first order kinetics. The half-life (t1/2) of peroxidase was 11.55 mm at 65 °C. The enthalpy (DH*) and free energy (DG*) of thermal denaturation of HRP were 92.22 and 102.54 k JmoI,-1 respectively, at 65 °C. It was suggested that horseradish peroxidase was quite thermostable and could be used for industrial applications.

H N BHATTI ,M N AKBAR ,M A ZIA ,