Abstract: The present invention relates to a purified casein phosphopeptide(CPP) having a novel amino acid sequence and a purified casein including same wherein the 25th Arg from N-terminal in a conventional CPP is replaced by Cys, rendering the CPPs to forming a dimer by disulfide bond. In the corresponding DNA sequence, cytosine is replaced by thymine to cause the amino acid replacement from Arginine(Arg) to Cysteine(Cys). The CPP or the casein containing same has an improved ability of solubilizing minerals and absorbing thereof in animals. The CPP or the beta-casein H containing same can be added to foodstuffs, beverages, medication, cosmetics, feed in an effective amount of enhancing a mineral absorption in animals. An oral composition comprising the beta-casein H or the inventive CPP and a pharmaceutically acceptable carrier can reduce or relieve a dentinal hypersensitivity.