[Cooxidation of potassium ferrocyanide and o-dianisidine by hydrogen peroxide catalyzed by horseradish peroxidase. Substrate-substrate activation].

The kinetics of cooxidation of potassium ferrocyanide and o-dianisidine by hydrogen peroxide catalyzed by horseradish peroxidase were studied. The peroxidation of potassium ferrocyanide is activated by o-dianisidine. A scheme illustrating the direct involvement of the enzyme in substrate-substrate activation is proposed. A method for determination of the rate constants of the first electron transfer from o-dianisidine to peroxidase (i. e. reduction of peroxidase E1 to E2) and of the constants for o-dianisidine binding by E1 was developed.