Affinity chromatography of a myeloma immunoglobulin M and its tryptic Fab and (Fc)5 fragments using lectins covalently coupled to sepharose 4B.

Abstract The mannose-specific lectin Concanavalin A and the galactose-specific Ricinus communis lectin were used as immobilized Sepharose 4B conjugates for the purification of IgM amd (Fc) 5 and for the separation of Fab from (Fc) 5 . No significant differences were found in the interaction of the two Sepharose-lectins with IgM and its tryptic Fab and (Fc) 5 fragments. Up to 30% of proteins in stored IgM preparations were not bound to Sepharose-lectins. It was shown that the non-bound material has low mol. wt protein contaminants. Whereas (Fc) 5 was bound to both types of lectin conjugate. Fab. even after pretreatment with 2% SDS, was not bound. The difference in binding properties between both types of fragment was utilised to fractionate them by means of affinity chromatography on Ricinus lectin-Sepharose. Fab poor in carbohydrate interacted with Con A-Sepharose, but not with Ricinus lectin-Sepharose.