Detection and characterization by high-performance liquid chromatography and mass spectrometry of two truncated goat alphas2-caseins.
The identification and characterization of truncated forms of goat alphas2-Cn variants A and E are reported. The two proteins, which have experimental Mr values of 24 183 and 24 227 Da, were detected as minor components in a goat milk sample from an autochthonous breed of southern Italy, 'Rossa Mediterranea', by reversed-phase high-performance liquid chromatography/electrospray ionization mass spectrometry (RP-HPLC/ESI-MS). Characterization of the amino acid sequences, performed by coupling trypsin digestion with matrix-assisted laser desorption/ionization mass spectrometry (MALDI-MS), RP-HPLC/ESI-MS and tandem mass spectrometry (MS/MS), demonstrated that the polypeptide chains correspond to the 1-204 sequence of mature alphas2-Cn variant A (component with Mr of 24 183 Da) and E (component with Mr of 24 227 Da), respectively. These components seem to be the product of a differential splicing of pre-messenger RNA during the translation process of the alphas2-Cn variants A and E.
Cunsolo
Vincenzo
V
Dipartimento di Scienze Chimiche, Università degli Studi di Catania, Viale A. Doria 6, 95125 Catania, Italy.
Muccilli
Vera
V
Saletti
Rosaria
R
Marletta
Donata
D
Foti
Salvatore
S
D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000032:analysis* / Q000737:chemistry*; D002851:Chromatography, High Pressure Liquid / Q000379:methods*; D006041:Goats; D008892:Milk / Q000737:chemistry*; D008969:Molecular Sequence Data; D008970:Molecular Weight; D010449:Peptide Mapping / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D002364:Caseins