[Purification and characterization of two peroxidases from hard wheat]

Two peroxidases A and B were purified from a borate buffer extract (pH = 10,4) of durum wheat semolina (Triticum durum), var. Bidi 17, by chromatography on DEAE-cellulose, salting out by 3M ammonium sulphate and two chromatographies on CM-cellulose; specific activities of peroxidase A or B were increased 114 or 66 fold. Molecular weight, amino acid composition, absorption spectrum, pH optimum, thermal stability and KM values differentiate the two enzymes. Ion Ca++ was shown as an activator of both peroxidase activities; the presence of an inhibitor in the crude extract was demonstrated.