Abstract
► We choice horseradish cv. “Balady” for purification of peroxidase in face of the local availability. ► The peroxidase was moderately stable to the denaturation induced by pH, heat and metal ions. ► The peroxidase oxidized some of phenolic compounds.
An anionic peroxidase POIII, molecular weight 56
kDa, was purified from the roots of horseradish cv. Balady. The enzyme exhibited high activity towards
o-phenylenediamine and guaiacol, while
o-dianisidine had moderate peroxidase activity. Pyrogallol and
p-aminoantipyrine had low affinity toward POIII. POIII was found to have a temperature optimum at 40
°C; the enzyme activity remained stable up to 40
°C and retained 87%, 51% and 29% of its activity at 50, 60 and 70
°C, respectively. The enzyme exhibited more than 50% of activity in the pH range between 4.0 and 8.0 with its pH optimum at 5.5. Several metal cations had partial inhibitory effects toward POIII. Fe
3+ enhanced the activity of the enzyme by 160% at 5
mM. All the metal chelators caused partial inhibitory effects toward POIII, except for EDTA at 1
mM, which had no effect on the enzyme.