Kinetics and chemistry of o-dianisidine and 3,3 ',5,5 '-tetramethylbenzidine oxidation reactions with hydrogen peroxide catalyzed by peanut and horseradish peroxidases

A comparative spectrophotometric study of peroxidase oxidation of o-dianisi dine and 3,3',5,5'-tetramethylbenzidine showed that the chemistry and kinet ics of these reactions in the presence of plant-peroxidases separated from cells of peanut and horseradish are similar. In the case of o-dianisidine o xidation, they depend on the nature of the buffer solution. A number of phe nols (resorcinol, hydroquinone, and pyrogallol) affect the rate of o-dianis idine oxidation reaction catalyzed by peroxidase of peanut and horseradish. These phenols inhibit enzyme action or play the role of a second substrate . These functions of phenols are determined by redox properties. The degree of the inhibiting action of resorcinol and the induction period of the rea ction in the presence of substrates (hydroquinone and pyrogallol) depend on the nature of a buffer solution.