An antifungal protein from flageolet beans

A protein with antifungal and hemagglutinating activities was isolated from dried flageolet beans (Phaseolus vulgaris cv. ‘Flageolet Bean’). The protein was unadsorbed on DEAE-cellulose but adsorbed on Affi-gel blue gel and CM-cellulose. The protein demonstrated antifungal activity against Mycophaerella arachidicola with an IC50 of 9.8 μM, but was inactive toward Fusarium oxysporum and Botrytis cinerea. Its hemagglutinating activity could not be inhibited by a variety of the sugars tested. The activity was stable up to 60 °C. At 70 °C, 75% of the hemagglutinating activity remained while no activity was discernible at and above 100 °C. The hemagglutinating activity was stable in the presence of a variety of monovalent, divalent and trivalent chlorides, and also when the ambient pH changed from 3 to 12. It did not exert any mitogenic activity on mouse splenocytes in vitro. Neither did it inhibit HIV-1 reverse transcriptase. It inhibited [3H-methyl]-thymidine incorporation into leukemia L1210 cells with an IC50 of about 4 μM.