Proteomic characterization of donkey milk "caseome".
At present, compared with bovine milk, the characterization of donkey milk caseins is at a relatively early stage progress, and only limited data are related to its genetic polymorphism. In this work, the heterogeneity of donkey caseome was investigated using a proteomic approach, based on one- (PAGE, UTLIEF) and two-dimensional (PAGE-->UTLIEF) electrophoresis, stained with either Coomassie Brilliant Blue or specific polyclonal antibodies, and structural MS analysis. These combined methodologies allowed the contemporary identification of donkey alpha(s1), alpha(s2), beta and kappa-CN with their related heterogeneity due to phosphorylation (alpha(s1), alpha(s2) and beta-CN), glycosylation (kappa-CN) and incorrect splicing of RNA in mRNA (deleted forms of alpha(s1)-CN and beta-CN). The results achieved showed 11 components for kappa-CN, six phosphorylated components for beta and alpha(s1)-CN and three main phosphorylated components for alpha(s2)-CN, each accounting for 10, 11 and 12 P/mole. At this regard, for the first time, the primary structure of the expressed protein corresponding to the only available donkey alpha(s2)-CN cDNA sequence was determined. Furthermore beta-CN was found in homozygous and heterozygous state for the occurrence of a genetic beta-CN variant having a MW value 28 mass units higher than the common beta-CN phenotype.
Chianese
Lina
L
Dipartimento di Scienza degli Alimenti, Università degli Studi di Napoli Federico II, Facoltà di Agraria, Via Università 100, Parco Gussone, I-80055 Portici (Napoli), Italy. chianese@unina.it
Calabrese
Maria Grazia
MG
Ferranti
Pasquale
P
Mauriello
Rosalba
R
Garro
Giuseppina
G
De Simone
Carmela
C
Quarto
Maria
M
Addeo
Francesco
F
Cosenza
Gianfranco
G
Ramunno
Luigi
L
D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000737:chemistry*; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional; D018397:Equidae; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D040901:Proteomics
D002364:Caseins