A friendly method for Raphanus sativus L (wild radish) peroxidase purification by polyelectrolyte precipitation

• Eudragit® negatively charged form complexes with radish peroxidase.
• Coulombic interaction between radish peroxidase–Eudragit in the complex formation.
• Easy method for peroxidase pre-purification from fresh radish roots extract.

The separation of radish peroxidase from a fresh Raphanus sativus L extract was carried out using precipitation with two commercially available negatively charged synthetic polyelectrolytes: Eudragit® L 100 and Eudragit® S 100. The enzyme was precipitated by polyelectrolyte addition at pH 4.00. The non-soluble complex formed was separated by simple centrifugation and re-dissolved by a pH change. The recovery of radish peroxidase biological activity was 50% of the initial activity in the homogenate for EuL and 45% for EuS, with 1.5-fold increase in its specific activity. The total Eudragit® concentration to precipitate the enzyme was very low: about 2 × 10−3% w/v. The volume of the final product decreased to 10% of the feedstock, concentrating the sample up to 10 times.