A Method for the Estimation of Peroxidase Activity in Milk

Open Access
Publisher Website
Google Scholar
Abstract
The method described possesses the advantages of speed, convenience and sensitivity. In this method, 0.5 ml of 2% p-phenylenediamine is oxidized by the lactoperoxidase of 0.1 ml milk in the presence of 0.1 ml of 0.3[image] H2O2. Five readings at intervals of 30 seconds are made on a colorimeter at 490 mu. Nonenzymatic oxidation is also determined on each sample of milk. Peroxidase activity is compared to a standardized curve of oxidized p-phenylenediamine. Under the conditions of the assay, the amount of color developed is proportional to time. The influence of H2O2 concentration, p-phenylenediamine concentration and enzyme concentration was studied and optimum conditions selected. An equation is presented for the conversion of peroxidase activity as measured by the proposed method to P. Z. number.

This publication has 5 references indexed in Scilit: