Isolation and characterization of luffacylin, a ribosome inactivating peptide with anti-fungal activity from sponge gourd (Luffa cylindrica) seeds.

A purification scheme involving ion exchange chromatography on DEAE-cellulose, affinity chromatography on Affi-gel blue gel, and ion exchange chromatography on CM-Sepharose and Mono S was employed to isolate a peptide with a molecular weight of 7.8kDa from sponge gourd seeds. The peptide, which was designated luffacylin, exhibited an N-terminal sequence with pronounced resemblance to that of the 6.5kDa arginine-glutamate rich polypeptide previously isolated from sponge gourd seeds. Luffacylin inhibited translation in a rabbit reticulocyte lysate system with an IC(50) of 140pM and reacted positively in the N-glycosidase assay for ribosome inactivating proteins. Luffacylin exerted anti-fungal activity against Mycosphaerella arachidicola and Fusarium oxysporum.