BINDING CAPACITY OF REDUCTIVELY FRAGMENTED ANTIBODIES TO THE 2,4-DINITROPHENYL GROUP.

Mild reductive cleavage of the polypeptide chains of antibodies to the 2,4-dinitrophenyl group has been carried out according to the methods of Porter and co-workers. The addition of epsilon-2,4-dinitrophenyllysine permitted almost complete retention of the antibody binding capacity upon transfer to IM propionic acid. Fractionation of the chains showed that the hapten was specifically bound to the A and not the B chains, and that about 30 percent of the B chains were bound to A in the presence of the bound hapten. The results confirm the conclusion of Porter and ca-workers that the A chain is the principal component of the antibody site, but suggest that the B chain may also contribute to the site.