Objectives: Peroxidases (POX), isoenzymes were purified to homogeneity from bulbs of Raphanus sativus
(Radish) grown in Burkina Faso and characterized for use as an alternative source of POX for biotechnological
applications.
Methodology and Results: The enzymes were purified using cation exchange, anion-exchange and
hydrophobic interaction chromatography. Two isoperoxidases, cationic POX1 and anionic POX2, were isolated
and purified 18.5 and 27.2 fold, respectively. Purified enzymes were found to be monomeric proteins with
molecular masses of 70 kDa and 47 kDa for POX1 and POX2, respectively, as determined by SDS-PAGE. The
effect of pH and temperature was done using guaicol as a substrate. The optimal pH of the both purified POX
was 5.6 and 80 % of its activity was retained at pH values between 4.0–8.0 after incubation for 2 h, but POX2
appeared to be highly stable than POX1. POX1 and POX2 had optimum temperatures of activity at 35° and 40
°C, respectively. Activities of these isoenzymes were determined using different phenolic substrates in the
presence and absence of ionic effectors. The results show that both POX activities were activated by bivalent
cations such as Mg2+ and Ca2+ but were inhibited by K+, Na+, Zn2+, EDTA and reducing compounds. While Ba2+
is an activator for POX2, it had no effect on POX1. They oxidize all the phenolic compounds used. The greatest
rate was obtained with ABTS and guaiacol, for POX1 and POX2, respectively.
Conclusions and application of findings: POXs oxidize a wide range of phenolic substrates and have high
stability at a wide range of pH. These properties make these enzymes potential biotechnological tools. They
could be use in industrial applications to produce food dyes, phenolic resins from natural phenolic compounds
or in the construction of biosensors and kits for analyses and diagnostics. They could play also an important
role in the oxidation of phenolic compounds in polluted water. This is interesting because it could be useful in
finding solutions to the thorny problem of recalcitrant phenolic compounds that resist to conventional methods
for bioremediation.

peroxidase purification characterization Raphanus sativus