Chromatographic separation of the isoforms of the ribosome inactivating protein, gelonin.

The three isoforms of gelonin were separated by affinity chromatography on concanavalin-A Sepharose into discrete components of Mr 31,500, 30,000 and 29,200. Their separation was achieved by apparent differences in interaction with the lectin due to variation in carbohydrate patterns. The Mr 30,000 component representing 67% of the total mixture was the most active in inhibiting protein synthesis in a cell free translation assay using rabbit reticulocyte lysates, although the other two were also active. An antibody prepared against the major fraction (Mr 30,000) reacted well with all three components, demonstrating immunological similarity. This purification may aid the structural elucidation of gelonin and preparation of hormonotoxins and immunotoxins.