FIG. 1.

The Cd²⁺-to-peptide stoichiometry expressed as the plot of initial Cd²⁺ concentration against the complexed Cd²⁺-to-peptide molar ratio. A total of 0.6 μmol of CP peptide (squares) and/or 1.2 μmol of HP peptide (circles) were incubated on TentaGel resin in 1 ml of Cd²⁺ containing 50 mM Tris-Cl (pH 7.4). In the case of HP peptide metal binding studies, 0.2 M KNO₃ was added as a background electrolyte. The portion of unbound Cd²⁺ was determined by atomic absorption spectrometry.