title: Mass spectrometric characterization of peptides derived by peptic cleavage of bovine beta-casein.
abstract: This study investigated the digestion of the milk protein beta-casein with pepsin under gastro-analogous conditions. Peptide sequences were identified using matrix-assisted laser desorption/ionization time-of-flight mass spectrometry with post-source decay as well as liquid chromatography-tandem mass spectrometry by means of database searching. The new software tool, Mascot Distiller, improved the identification rate remarkably. In the case of small peptides, such as di- and tri-peptides, which are promising candidates for intestinal absorption and possible biological effects, identification was possible only after spectrum simulation and manual matching. A list of 41 identified peptides having 2-36 amino acids is given, and unexpected cleavage sites for pepsin are reported. Sequence coverage was 75%.
authors.affiliation: Institute of Pharmaceutics and Biopharmaceutics, Martin Luther University Halle-Wittenberg, Wolfgang-Langenbeck-Strasse 4, 06120 Halle (Saale), Germany.
authors.forename: Christian E H
authors.initials: CE
authors.lastname: Schmelzer
authors.forename: Regina
authors.initials: R
authors.lastname: Schöps
authors.forename: Renate
authors.initials: R
authors.lastname: Ulbrich-Hofmann
authors.forename: Reinhard H H
authors.initials: RH
authors.lastname: Neubert
authors.forename: Klaus
authors.initials: K
authors.lastname: Raith
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods*
chemical_list: D002364:Caseins