Abstract
1. A method is described for the colorimetric determination of peroxidase with N,N-dimethyl-p-phenylenediamine. The amount of red pigment formed by peroxidase is proportional to the concentration of enzyme and to the time of incubation during the first 40 to 90 seconds. The influence of the concentration of enzyme, N,N-dimethyl-p-phenylenediamine, H2O2, the time of incubation, pH, the temperature, and the possible interference by oxidizing and reducing agents of tissues has been tested.