Purification and characterization of a cationic peroxidase image in Raphanus sativus

A short distance migrating cationic peroxidase from Korean radish seeds (Raphanus sativus) was detected. Cationic peroxidase image was purified to apparent homogeneity and characterized. The molecular mass of the purified cationic peroxidase image was estimated to be about 44 kDa on SDS-PAGE. After reconstitution of apoperoxidase image with protohemin, the absorption spectra revealed a new peak in the Soret region around 400 nm, which is typical in a classical type III peroxidase family. The optimum pH of peroxidase activity for o-dianisidine oxidation was observed at pH 7.0. Kinetic studies revealed that the reconstituted cationic peroxidase image has image values of 1.18 mM and of 1.27 mM for o-dianisidine and H2O2, respectively. The cationic peroxidase image showed the peroxidase activities for native substrates, such as coumaric acid, ferulic acid, and scopoletin. This result suggested that cationic peroxidase Cs plays an important role in plant cell wall formation during seed germination.