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

Ilona Trawczyńska

doi:10.3390/catal10030323

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.

Highlights

Enzymes are highly efficient and selective biological catalysts under specific conditions, which makes their use extremely popular in various bioprocesses [1,2]
One of the common enzymes ubiquitously found in all living organisms is catalase [3,4]
The heme-containing catalase bonds with and breaks up a molecule of hydrogen peroxide into harmless water and oxygen atom. This oxygen atom is joined to the iron atom present in the heme (Compound I)

Summary

Introduction

Enzymes are highly efficient and selective biological catalysts under specific conditions, which makes their use extremely popular in various bioprocesses [1,2]. Enzymes from various sources exhibit some differences in structure and properties [5,6,7]; all of them decompose hydrogen peroxide into molecular oxygen and water in the two-step process shown in Equation (1). The heme-containing catalase bonds with and breaks up a molecule of hydrogen peroxide into harmless water and oxygen atom. This oxygen atom is joined to the iron atom present in the heme (Compound I). A second hydrogen peroxide molecule binds and is divided into two parts. After the second oxygen atom is attached to the iron atom the molecules of water and oxygen gas are released [8]

Methods

Results

Conclusion