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CPP-ACP acts as a source for calcium and phosphate when attached to dental plaque and tooth surfaces. The CPP molecule is the transporter for the ACP molecule, localizing the highly soluble calcium-phosphate phase at the tooth surface (E. Reynolds, Cai, Shen, & Walker, 2003). Calcium and phosphate ions released from the CPP-ACP readily spread and deposit in part demineralized crystallites of teeth surface. Casein phosphopeptide includes a cluster of phosphoserine (Ser(P)) residues which have the capability to bind amorphous calcium phosphate and lead to increasing its solubility and preventing mineral precipitation (Iijima et al., 2004; Reeves, 1958; E. C. Reynolds, 1998) the CPP and Calcium act together through the negatively charged residues of the peptide (–Ser(P)–Ser(P)–Ser(P)–Glu–Glu–) as well as other acidic residues of the phosphopeptide sequence (K. J. Cross, Huq, Palamara, Perich, & Reynolds, 2005). Casein phosphopeptide as1-casein X-5P (f59–79) and b-casein X-4P (f1–25) can maximally bind 21 and 24 calcium ions and 14 and 16 phosphate ions per molecule, respectively, producing a metastable, colloidal solution (K. J. Cross et al., 2005). An equivalence among free and CPP-bound calcium and phosphate ions finally happens to depend happening the situations of the environment, on condition that a reservoir of bioavailable ions for inhibition of demineralization and elevation of remineralization. CPP-ACP is having four stages to inhibits demineralization.
1- CPP-ACP provide as like a protective physical barrier through binding to the apatite crystal face and blocking active sites of dissolution(K. Cross, Huq, & Reynolds, 2007).
2- various amino acid residues that located on CPP work like acid buffers and remain amino acid can be destruction to create ammonia, that leads to increasing the pH of cariogenic plaque (K. Cross et al., 2007; K. J. Cross et al., 2005; Iijima et al., 2004; Reeves, 1958; E. C. Reynolds, 1998).
3- CPP-ACP preserves calcium and phosphate ion concentrations inside dental plaque which observe as saturation phase on to tooth enamel(E. Reynolds et al., 2003).
4-CPP-ACP may change plaque microbial composition to be a less cariogenic effect form through inhibition the adherence and prevent to form colonization of specific bacteria. CPP can integration with the pellicle in conversation for albumin; that inhibits the adherence of S. sobrinusand S. mutans via obstructive specific receptors, competitively binding calcium to prevent calcium bridging of bacterial cells, and causing electrostatic repulsion by binding to the surface of bacteria (Rose, 2000a; Schüpbach, Neeser, Golliard, Rouvet, & Guggenheim, 1996). calcium and phosphate ions are liberating from CPP-ACP is driven by 1) equilibrium, 2) conformational changes, 3) pH and 4) enzymatic activity. First the CPP-ACP will release more from phosphate and calcium ions from the CPP-ACP when the concentration both calcium and phosphate ions in solution decreases to maintain equilibrium. Second, the CPP has binding affinities for apatite, pellicle, mucin, proline-rich proteins and bacteria; this binding encourages a conformational change in the CPP to be release calcium and phosphate ions from the nanocomplex (K. J. Cross et al., 2005; E. Reynolds et al., 2003; Rose, 2000a, 2000b; Schüpbach et al., 1996) Third, the phosphorylated groups of the peptide come to be protonated, so reducing the net negative charge and lead to the release of positive calcium and phosphate ions from the CPP-APC when ph degree decreases (Cochrane, Saranathan, Cai, Cross, & Reynolds, 2008; E. Reynolds, 1997).Fourth,CPP is contain enzymatic hydrolysis to contributed release of the calcium and phosphate ions (E. Reynolds et al., 2003; R. Reynolds, Carey, & Herschkowitz, 1989).