title: Enzymatic release of neocasomorphin and beta-casomorphin from bovine beta-casein.
abstract: 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.
authors.affiliation: Research Institute for Food Science, Kyoto University, Uji, Japan.
authors.forename: Y
authors.initials: Y
authors.lastname: Jinsmaa
authors.forename: M
authors.initials: M
authors.lastname: Yoshikawa
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000378:metabolism*; D002417:Cattle; D002851:Chromatography, High Pressure Liquid; D004723:Endorphins / Q000302:isolation & purification / Q000378:metabolism*; D008969:Molecular Sequence Data; D009842:Oligopeptides / Q000302:isolation & purification / Q000378:metabolism*
chemical_list: D002364:Caseins; D004723:Endorphins; D009842:Oligopeptides; C400131:tyrosyl-prolyl-valyl-glutamyl-prolyl-phenylalanine; C021968:beta-casomorphins