Partial characterization of peroxidase isoenzymes from rust-affected wheat leaves

Four anodic peroxidase isoenzymes from wheat leaves were purified by column chromatography and their kinetic behavior with common substrates were examined. One isoenzyme is more active in wheat resistant to stem rust fungi and differed from the others in carbohydrate content and also by a specific activity 2–4-fold higher with non-physiological electron donors. As a substrate, eugenol exhibited kinetic behavior different from p-phenylenediamine, guaiacol or o-dianisidine with all isoenzymes. All four isoenzymes showed similar pH and temperature optima and kinetic behavior and apparent K_m values for both H₂O₂ and non-physiological electron donors.