title: Novel opioid peptides derived from casein (beta-casomorphins). II. Structure of active components from bovine casein peptone.
abstract: Material with opioid activity had been isolated from an enzymatic casein digest. It was shown to contain a pure heptapeptide with the sequence Tyr-Pro-Phe-Pro-Gly-Pro-Ile. The identity between the opioid principle and the peptide was proven by the fact that chemical reagents or enzymes effecting one would effect the other. After carboxypeptidase Y digestion a pentapeptide, Tyr-Pro-Phe-Pro-Gly, could be isolated; this peptide showed a higher opioid activity than the heptapeptide. The opioid peptides were highly resistant towards proteolysis, even by pronase. The sequence of the hepatapeptide identified it as a fragment of bovine beta-casein. Therefore it was named beta-casomorphin.
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002268:Carboxypeptidases; D002364:Caseins; D002417:Cattle; D004723:Endorphins / Q000494:pharmacology; D010446:Peptide Fragments / Q000494:pharmacology; D010447:Peptide Hydrolases
chemical_list: D002364:Caseins; D004723:Endorphins; D010446:Peptide Fragments; C021968:beta-casomorphins; D002268:Carboxypeptidases; D010447:Peptide Hydrolases