Enzymatic release of neocasomorphin and beta-casomorphin from bovine beta-casein

Peptides. 1999;20(8):957-62. doi: 10.1016/s0196-9781(99)00088-1.


Conditions for the release of beta-casomorphin-7 from bovine beta-casein by gastrointestinal proteases in vitro were investigated. beta-Casomorphin-7 was released only from a genetic variant of beta-casein containing a His residue at the 67th position of the peptide chain. Elastase cleaved the peptide bond between Ile66 and His67, releasing the carboxyl terminus of beta-casomorphin-7. Pepsin and leucine aminopeptidase were required to release the amino terminus of this peptide. beta-Casomorphin-9, -13, and -21 also were isolated, and their opioid activities were measured. In this study, we also isolated a novel opioid peptide neocasomorphin-6 (Tyr-Pro-Val-Glu-Pro-Phe), which was released by action of trypsin or pepsin and chymotrypsin.

MeSH terms

  • Amino Acid Sequence
  • Animals
  • Caseins / metabolism*
  • Cattle
  • Chromatography, High Pressure Liquid
  • Endorphins / isolation & purification
  • Endorphins / metabolism*
  • Molecular Sequence Data
  • Oligopeptides / isolation & purification
  • Oligopeptides / metabolism*


  • Caseins
  • Endorphins
  • Oligopeptides
  • tyrosyl-prolyl-valyl-glutamyl-prolyl-phenylalanine
  • beta-casomorphins