Purification of glysojanin, an antifungal protein, from the black soybean Glycine soja

A monomeric protein, with a molecular mass of 25 kDa and an N-terminal sequence resembling a segment of chitin synthase, was isolated from the seeds of the black soybean Glycine soja. The protein, designated glysojanin, demonstrated potent antifungal activity against the fungi Fusarium oxysporum and Mycosphaerella arachidicola. It inhibited HIV-1 reverse transcriptase with an IC50 of 47 mumol/L, [methyl-H-3]thymidine incorporation by mouse spleen cells with an IC50 of 175 mumol/L, and translation in the rabbit reticulocyte lysate with an IC50 of 20 mumol/L. Glysojanin was purified using a procedure that involved ion-exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, ion-exchange chromatography by fast protein liquid chromatography on Mono S, and gel filtration by fast protein liquid chromatography on Superdex 75.