Crystalline Catalase, A Peroxidase

Abstract

A series of new functions of catalase are descr. Dilute solns. of crystalline cow liver catalase, in the presence of H2O2 can rapidly peroxidize a variety of compounds. alpha-Naphthol and p-phenylenediamine are oxidized to indolphenol purple; p-aminobenzoic acid, sulfathiazole, epinephrine ephedrine sulfate, and tyrosine are coupled with catechol by oxidation to form colored compounds. Pyrogallol, catechol, epinephrine and p-phenylenediamine are also oxidized to colored compounds. Thus, catalase can act as a peroxidase, but peroxidase cannot act as catalase (decompose H2O2 without the presence of a 2d substrate). The new coupled oxidation reactions are given by very dilute catalase solns. They require added H2O2. That a peroxidase reaction on large molecules similar to those descr. in this paper had not been observed previously with catalase is due to unsuitable choice of combination of substrates. These results point to an important physiological function of catalase.