New Method of Determining Kinetic Parameters for Decomposition of Hydrogen Peroxide by Catalase

Abstract

The presented study investigates the kinetic properties of catalase during hydrogen peroxide decomposition reaction. A novel and simple method is hereby proposed for the determination of the enzyme deactivation rate constant (kd) and the decomposition of H2O2 reaction rate constant (kr). Available methods allow the kd constant to be determined only based on previously experimentally determined kr. The presented method differs from the conventional procedure. Known initial and final concentrations of hydrogen peroxide enable determination of both constants at the same time based on data from only one experiment. The correctness of the new method proposed here in determining the reaction rate constant was checked by comparing the obtained constant values with the calculated values according to the commonly used Aebi method. The method was used to analyze in detail the effect of pH (3–10) and temperature (10–45 °C) of the reaction medium on kinetic constants. The value of the constant kd increases together with the value of pH and temperature. In addition, the activation energy for decomposition reaction and deactivation reaction was found to be Er = 14 kJ mol−1 and Ed = 56.8 kJ mol−1 respectively.