Partial Purification and Characterization of Peroxidase (E.C. 1.11.1.7) from two Varieties of Cowpea, Inoculated with Root-Knot Nematode, Meloidogyne Incognita

The peroxidase preparations from two varieties of cowpea (Pusa Barsati), (nematode-uninoculated and inoculated); C 152, (nematode-uninoculated and inoculated), were purified to homogeneity through a series of steps including (NH₄)₂ SO₄, fractionation and gel filtration of Sephadex—G—200 columns. The homogeneity of the preparations were judged and confirmed through polyacrylamide gel electrophoresis. Fifteen days after inoculation, number of peroxidase isozymes resolved on gel surface from both the cultivars were in excellant agreement with elution profile of enzyme preparation obtained through Sephadex G—200. The parameters used for characterization of the purified peroxidase isozymes were temperature, pH, K_m, V_max, inhibitors and storage life. The pH optima of newly synthesized isozymes of both the cultivars is pH 7.0. Temperature optima of these isozymes were stable at temperature ranging from 10–40°C. Caffeic acid has more inhibitory effect on the isozymes of peroxidase from both the cultivars than the chlorogenic acid at 1000 fold molar concentration. The K_m and V_max values of the newly synthesized isozyme varied considerably from the remaining zymograms indicating its distinctness. The data revealed that the isozymes appearing after infection of the host in both the cultivars differed considerably.