Chemical Structure Studies of Cow ϰ‐Casein: Study of the soluble tryptic peptides

Abstract

Abstract The sequences of 13 tryptic peptides of cow ϰ A ‐casein (accounting for about one half of the amino acid residues present in the protein) were established. The rennin sensitive linkage could be located in a large fragment (36 residues). ϰ‐casein consists of a hydrophilic part (ϰ‐caseino‐glycopeptide) and of a hydrophobic moiety (para‐ϰ‐casein); in this latter, however, several quite hydrophilic sequences were characterized. Another feature of the ϰ‐casein structure is the frequent duplication or triplication of certain amino acids (Pro‐Pro; Phe‐Phe; Gln‐Gln‐Gln‐Asn‐Glu‐Glu‐Glu; Pro‐Pro‐Lys‐Lys‐Asn‐Gln‐; etc. …).