Estimation of calcium-binding constants of casein phosphopeptides by capillary zone electrophoresis Original Research Article

Measurement of electrophoretic mobilities of bovine casein phosphopeptides (αs1-CN(59–79), αs1-CN(43–58), β-CN(1–25), and β-CN(33–48)) and their dephosphorylated analogues at different calcium concentrations enabled the calculation of calcium-binding constants in the range of pH 5–8. Binding constants showed a maximum at pH 7 and were in the range 0.1–0.5 mM−1. The decrease at pH 8 might be attributed to the presence of carbon dioxide, leading to competitive binding of calcium ions. Phosphorylated peptides exhibited higher binding constants than their dephosphorylated analogues.