Complexes of Casein Phosphopeptide and Calcium Phosphate Prepared from Casein Micelles by Tryptic Digestion

Casein phosphopeptide (CPPcm), which inhibits the precipitation of calcium phosphate in the intestines, was prepared as a CPPcm-calcium phosphate complex from casein micelles (casein–calcium phosphate conjugates). CPPcm was eluted as seven peaks from a Q-sepharose FF column, the major peaks being identified and agreeing with those of the phosphopeptides (CPPcn) from acid-precipitated casein. The major components of CPPcm were αs1-CN-5P(f59–79) and β-CN-4P(f1–25), CPPcm containing more αs1-CN-5P (f59–79) than CPPcn. The complexes of CPPcm and calcium phosphate contained twice the quantity of calcium phosphate as those of CPPcn.