Preparation and characterization of Ca2+-Zn2+-derivatives of lentil and pea lectins and comparison with the native forms

Ca²⁺-Zn²⁺-derivatives of lentil and pea lectins were prepared for the first time by a unique method involving dialysis of the native Ca²⁺-Mn²⁺-lectins against large excesses of metal ions in pH 4.0 buffer. Each derivative contained about 1.5 g atoms of Ca²⁺ and about 1 g atom of Zn²⁺ per monomer. The derivatives were found to be identical to their respective native forms, both in molecular weight and carbohydrate binding activities. Solvent proton relaxation dispersion measurements were used to characterize both the Ca²⁺-Zn²⁺- and Ca²⁺-Mn²⁺-complexes of the lentil lectin.