A small protein (MW .apprx. 14,000) rich in cysteine/half-cystine was isolated from camel milk by exclusion chromatography and reverse-phase high performance liquid chromatography. The N-terminal amino acid sequence shows a region with several positional identities with .alpha. and .beta.-caseins, which however lack cysteine residues; positions 16-20 are identical and involve the serine residues that were found to be phosphorylated in .beta.-caseins.