[Horseradish peroxidase: kinetic studies and optimization of peroxidase activity determination using the substrates H2O2 and 3,3',5,5'-tetramethylbenzidine].

Horseradish peroxidase is often used as a labelling and indicator enzyme in enzyme immunoassays. In order to optimize the peroxidase activity determination, the kinetics of the catalytic reaction were investigated in relation to the concentration of H2O2 and 3,3',5,5'-tetramethylbenzidine, at different pH values, reaction temperatures and incubation times. On the basis of the results, a test procedure is presented, which enables the quantitative determination of peroxidase in the range 0-200 ng/l. In addition, methods are described for the determination of 3,3',5,5'-tetramethylbenzidine and H2O2.