Isolation of a novel peroxidase from French bean legumes and first demonstration of antifungal activity of a non-milk peroxidase.

A novel antifungal protein with its N-terminal sequence bearing similarity to the C-terminal sequences of peroxidases was isolated from French bean legumes. The protein, which possessed a molecular weight of 37 kDa, was adsorbed on Affi-gel blue gel and CM-Sepharose. The protein exhibited peroxidase activity with a Km of 58 microM and a Vmax of 3.36 U/nmol. Optimal peroxidase activity was found at 22 degrees C and pH 4. It exerted antifungal activity against a variety of fungal species including Coprinus comatus, Mycosphaerella arachidicola, Fusarium oxysporum and Botrytis cinerea. It inhibited the activities of alpha-glucosidase and beta-glucosidase but was without any inhibitory effect on HIV-1 reverse transcriptase.