The capability of certain lectins to agglutinate cells and induce mitogenic activity seems to parallel the bindng of simple, specific saccharides to these plant proteins. Like most other lectins, Concanavalin A has an absolute transition metal ion and calcium ion requirement for binding to saccharides. Although the three dimensional structure of Concanavalin A has been detailed by X-ray crystallographic techniques, the exact location of the saccharide site remains uncertain. Hence, an analysis of the mechanism of lectin specificity awaits an identification of the amino acids involved in sugar binding and an understanding of the roles played by metal size and charge. Water proton relaxation rate studies (using divalent europium as a calcium ion substitute) and fluorescence spectroscopic studies of affinity labeled saccharide derivatives will be used to locate the sugar site and examine the role played by metals in forming the site in Concanavalin A. BIBLIOGRAPHIC REFERENCE: "The Activaton of Concanavalin A by Lanthanide Ions" by A.D. Sherry, A.D. Newman nd C. Gutz, Biochemistry, 14, 2191-2196 (1975).