Interactions of an ovalbumin glycopeptide with concanavalin A

The interaction of a highly purified glycopeptide isolated from ovalbumin with Concanavalin A has been investigated by measuring solvent proton relaxation rates over a wide range of magnetic fields. We find that binding of the glycopeptide to Mn-Ca-Concanavalin A uniformly reduces the solvent proton relaxation rates in the same manner as that of simple saccharides such as methyl α-D-mannopyranoside, but that the magnitude of the reduction is not as great. Furthermore, we observe that the glycopeptide is capable of precipitating the lectin, and that the precipitation reaction can be readily reversed by addition of methyl α-D-mannopyranoside. The latter results indicate that the branched chain glycopeptide appears to be bivalent with respect to binding by the lectin.