Inhibition kinetic and thermal inactivation of horseradish peroxidase in the presence of Zn2+ ion

AbstractPeroxidase as a heme ‐containing metalloprotein, is an important enzyme for food industries. Hence, the current study is aimed to evaluate the inhibitory properties of zinc ion in terms of activity and thermal stability of horseradish peroxidase (HRP) in the range of 40–70°C for 1–45 min. The results showed that zinc ion potently inhibited HRP activity by noncompetitive mechanism. The thermal inactivation of enzyme followed first‐order reaction kinetics in the presence of ZnCl2up to 300  μM. However, higher concentrations of Zn2+‐induced irregularities in HRP thermo inactivation pattern from first‐order kinetics. According to the kinetic parameters,K andEa, the rate of reactivation of HRP may be dependent on the amount of zinc ion, inactivation time, and heating duration.Practical applicationsThermal inactivation kinetics of HRP was investigated in the presence of Zn2+. The results showed that thermal inactivation of HRP followed first ‐order kinetics for up to 300 μM of Zn2+. HRP inactivation was consistent with biphasic models for higher concentrations of Zn2+ at 60 °C. The transition free energy of inactivation confirmed that zinc ion increased the enzyme unfolding transition states stability as denatured structure of HRP is more favorable than native one in this condition. Moreover, reactivation potential of enzyme decreased by increasing the zinc ion concen tration.
Source: Journal of Food Biochemistry - Category: Food Science Authors: Tags: FULL ARTICLE Source Type: research