No abstract

Mouse IgA myeloma proteins have been studied for the structure of their polypeptide chains and papain fragments. Heavy and light chains, Fab and Fc fragments were shown to have molecular weights closely corresponding to their IgG equivalents and the mass ratio of Fab and Fc fragments indicate the presence of two Fab and one Fc fragments per IgA monomer. The results, taken together with the available hapten-binding data, suggest that a single light-heavy chain pair constitute a hapten-binding site in IgA. In addition, structural studies performed on normal mouse IgA indicate the presence in their structure of dimerized light chain as had been previously reported for IgA myeloma proteins.