title: Peptidomic approach based on combined capillary isoelectric focusing and mass spectrometry for the characterization of the plasmin primary products from bovine and water buffalo beta-casein.
abstract: The main peptides produced by hydrolysis of water buffalo beta-casein with plasmin were characterized by capillary electrophoresis and mass spectrometry and compared with their bovine homologous. A novel breakdown product arising from the hydrolysis of water buffalo beta-casein, originated by the presence of a plasmin-sensitive Lys bond at position 68 was identified, which was not present in bovine beta-casein. On the basis of this evidence, an improved procedure for the detection and the differentiation of the products of plasmin hydrolysis of bovine and water buffalo beta-casein by capillary isoelectric focusing was set-up. In the experimental conditions, the gamma-casein from the two species was efficiently separated. Comparison of the capillary electropherograms with those obtained by ultra-thin-layer isoelectric focusing, the reference method for routine analysis of plasmin digests of casein, suggests that capillary electrophoresis isoelectric focusing may constitute a successful alternative to the traditional slab gel electrophoresis analysis of plasmin digests of casein either for basic structural studies or for applications in the quality assessment of dairy products.
authors.affiliation: Dipartimento di Scienza degli Alimenti, University of Naples Federico II, Parco Gussone, Portici I-80055, Italy.
authors.forename: Andrea
authors.initials: A
authors.lastname: Somma
authors.forename: Pasquale
authors.initials: P
authors.lastname: Ferranti
authors.forename: Francesco
authors.initials: F
authors.lastname: Addeo
authors.forename: Rosalba
authors.initials: R
authors.lastname: Mauriello
authors.forename: Lina
authors.initials: L
authors.lastname: Chianese
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D002020:Buffaloes / Q000378:metabolism*; D002364:Caseins / Q000032:analysis*; D002417:Cattle; D002852:Chromatography, Ion Exchange; D005260:Female; D005341:Fibrinolysin / Q000032:analysis*; D006868:Hydrolysis; D007525:Isoelectric Focusing; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
chemical_list: D002364:Caseins; D010455:Peptides; D005341:Fibrinolysin