J. Singh, A. Dubey, S. K. Diwakar, S. K. Rawat, N. Batra, and A. Joshi
Ionically bound peroxidases were salt extracted and ethanol precipitated from the pulp of four Indian apple varieties i.e., Chocklaty, Kali devi, Kinnaur and Maharaji. All peroxidases showed their temperature optima at 40oC. Various phenolic compounds activated all apple peroxidases by 25-240% but protocatechuic acid inhibited (32%) the Kali devi peroxidases. The activities from all apple varieties were strongly improved in the buffer containing metal ions like Fe2+ (169-364%) and Cu2+ (3-103%), indicating their role as cofactors. Mg2+ inhibited (23%) the peroxidases from Chocklaty, Kinnaur and Kali devi. 25-45% inhibition was observed in all the apple peroxidases by Mn2+. Zn2+ established an inhibition (24-38%) to Chocklaty, Kinnaur and Maharaji peroxidases. Methionine, proline, tryptophan and valine stimulated all apple peroxidases. Cysteine stimulated (100%) the Maharaji peroxidases but inhibited (17-57 %) the others.
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