title: A signature protein-based method to distinguish Mediterranean water buffalo and foreign breed milk.
abstract: A novel genetic variant at the αs1-casein locus of water buffalo (WB), 8-residue shorter than its wild-type has been found and sequenced. The internal deletion of the peptide E(35)KVNELsT(42) was confirmed by the isolation of the junction peptide. The 8-residue deletion mutant has a molecular weight that is 919 Da less than that of the wild-type. The novel isoform with a unique f35-42 deletion could be the result of the skipping of exon 6, generating an exon 6-deleted variant of αs1-casein. The wild-type and its shortened αs1-casein forms were found to co-exist in many individual milk samples. In contrast, the 8-residue, internally deleted αs1-casein variant did not occur in water buffaloes of the Mediterranean breed reared in Italy. Wild-type αs1-casein has 6 to 8 phosphate groups (P) while the internally deleted form 6 and 7P per molecule.
authors.affiliation: Università degli Studi di Napoli "Federico II", Facoltà di Agraria Via Università, 100 80055 Portici, Napoli, Italy. caira@unina.it
authors.forename: Simonetta
authors.initials: S
authors.lastname: Caira
authors.forename: Gabriella
authors.initials: G
authors.lastname: Pinto
authors.forename: Valentin A
authors.initials: VA
authors.lastname: Balteanu
authors.forename: Lina
authors.initials: L
authors.lastname: Chianese
authors.forename: Francesco
authors.initials: F
authors.lastname: Addeo
mesh_terms: D000595:Amino Acid Sequence; D000818:Animals; D001947:Breeding; D002020:Buffaloes / Q000145:classification / Q000235:genetics* / Q000378:metabolism; D002364:Caseins / Q000737:chemistry* / Q000235:genetics; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D016002:Discriminant Analysis; D019083:Mediterranean Region; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D010449:Peptide Mapping; D040901:Proteomics / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
chemical_list: D002364:Caseins