Purification and Characterization of Peroxidase Isoenzymes from Green Peas (Pisum sativum) |
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| Authors: | B HALPIN R PRESSEY J JEN N MONDY |
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| Affiliation: | Cornell Univ., is now with the Dept. of Horticulture, Louisiana State Univ., Baton Rouge, LA 70803.;Plant Physiology Unit, USDA −ARS Research Center, Athens, GA, 30613.;Dept. of Food Science and Technology, Univ. of Georgia, Athens, GA 30601.;Institute of Food Science, Div. of Nutritional Sciences, Cornell Univ., Ithaca, NY 14853. |
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| Abstract: | Peroxidase isoenzymes were purified from green peas with ion-exchange chromatography on DEAE- and S-Sepharose. Three isoenzymes were identified, one neutral (N) and two cationic (C1, C2). N was extremely heat labile, with 50% original activity lost after heating 1.5 min at 25°C. N had Km values (pH 5.0) of 10.2 mM and 2.6 mM for guaiacol and H2O2, respectively. C1 and C2 retained activity on heating at 30–70°C. C1 was able to reactivate after thermal inactivation. Km values for guaiacol/H2O2 were 10.8 mM/7.2 mM (pH 5.0) and 10.8 mM/4.3 mM (pH 6.0) for C1 and C2, respectively. The three isoenzymes exhibited different peroxidase activities with different H-donors, different sensitivities to cyanide and different abilities to catalyze oxidation of indoleacetic acid. |
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