Precipitin and mitogenic behavior of dimeric and tetrameric concanavalin A.

The results of double diffusion and quantitative precipitin tests show that in contrast to the concanavalin A tetramer, the dimer is incapable of precipitating glycogen. The results support previous work suggesting that dimers composed of two fragmented monomer units possess only one binding site for carbohydrate (McKenzie and Sawyer, J. Biol. Chem. 1973. 248: 549). On the other hand, dimer and tetramer species had similar mitogenic activity as measured by the incorporation of radioactive thymidine by mouse spleen lymphocytes and induced cap formation to similar degrees. Results are discussed in terms of the affinity and valency of the polymeric forms and their stability at the cell surface.