Tryptic digestion of Xenopus IgM and IgY molecules

Xenopus IgM and IgY molecules were digested by trypsin. Their respective fragments were separated by gel filtration and immunoadsorption. The purified fragments were characterized by SDS-PAGE and immunoblotting. Tryptic digestion of Xenopus IgM resulted in the release, at a low yield, of hexameric Fcmu, and of monovalent Fabmu fragments. The digestion of Xenopus IgY antibodies led to the recovery of divalent and monovalent Fab nu fragments. The antigen-binding property of these fragments was demonstrated. No Fc nu fragments of appreciable size could be detected.