Characterization of phosphopeptide derived from bovine beta-casein: an inhibitor to intra-intestinal precipitation of calcium phosphate.

Casein phosphopeptide (CPP), a highly phosphorylated peptide fragment which inhibits the formation of hydroxyapatite crystal was isolated from pooled ileal contents of rats fed a semi-synthetic diet containing bovine beta-casein. The estimated amino acid sequence of the CPP was shorter than that of the trypsin-digested beta-casein but the core region consisting of consecutive bindings of phosphoserine was fully conserved. A moderate and exchangeable binding to Ca2+ of the CPP molecule well substantiates the high absorbability of calcium from milk and dairy products.