Purification and characterization of cationic peroxidase from ginger (Zingiber officinale)

Abstract

The cationic peroxidase (GPII) was purified to homogeneity by anion exchange chromatography using DEAE–Sepharose column followed by cation exchange chromatography using CM–Sepharose column and finally Sephacryl S-200 column. The molecular mass of GPII was 42 kDa. GPII shows oxidizing activity with several phenolic compounds by using H2O2 as the second substrate. The natural plant phenolic compounds as pyrogallol, catechol, and guaiacol were found to be excellent electron donors for the enzyme compared to other phenolic compounds. GPII exhibited Km values of 3.1 and 7.1 mM and Vmax values of 0.6 and 0.31 units/assay using H2O2 and guaiacol as substrates, respectively. The enzyme exhibited maximal peroxidase activity at broad pH’s 6.0–7.5 and 50 °C. GPII was thermal stable up to 50 °C and retained 66% of its activity at 70 °C after 1 h incubation. The GPII activated by most divalent cations tested and inhibited by Hg2+ and Cu2+ cations.