Catalatic activity of lactoperoxidase in the presence of SCN-.

Lactoperoxidase catalyzed the catalatic decomposition of H2O2 in the presence of SCN-. The pH optimum for O2 evolution was 8.5, while the enzyme activity as disclosed by the rate of H2O2 disappearance was optimal at 4.5. Since the catalatic activity of lactoperoxidase was SCN- dependent, and no O2 was evolved, when H2O2 was added to OSCN- in the absence of lactoperoxidase, an enzyme-OSCN complex may be assumed to be an intermediate in the catalatic activity of lactoperoxidase.