抄録
The binding of calcium to K-casein and para K-casein was studied by infrared spectra. The binding of calcium to the phosphoryl groups of K-casein reached a plateau above 1mM CaCl2, and the binding to the carboxyl groups proceeded linearly up to 3mM CaCl2, and slowly above 3mM CaCl2, which were nearly identical to the results of K-casein previously reported. The binding to carboxyl groups of para K-casein proceeded similarly. The con-formational changes of K-casein accompanying the bindings were determined by circular dichroism and ultraviolet spectra. The obtained results suggest that the hydrophobic sites of K-casein are exposed to solvent without a change in secondary structure of the protein. Calcium promoted the dissolution of para K-casein in the presence of urea.
