Identification of C-terminally truncated forms of beta-lactoglobulin in whey from Romagnola cows' milk by two dimensional electrophoresis coupled to mass spectrometry.
Four minor protein components were detected in whey from Romagnola cows' milk by polyacrylamide gel isoelectric focusing and two dimensional gel electrophoresis. Individual protein spots were transferred by electroblotting on to a polyvinylidene difluoride membrane and isolated by cutting out the relevant area. After in situ trypsinolysis, a portion of the digest was analysed directly by matrix-assisted laser desorption ionization-time of flight mass spectrometry. The mass profile allowed us to establish a correlation between beta-lactoglobulins A and B and the four minor whey protein components. They were identified as C-terminally truncated beta-lactoglobulin A and B variants with missing N-terminal peptides, beyond residues in the range 100-123 and 136-147 respectively. Two of the minor components were related to beta-lactoglobulin A and two to beta-lactoglobulin B.
Zappacosta
F
F
Servizio di Spettrometria di Massa, CNR, Napoli, Italia.
Di Luccia
A
A
Ledda
L
L
Addeo
F
F
D000595:Amino Acid Sequence; D000818:Animals; D002417:Cattle; D015180:Electrophoresis, Gel, Two-Dimensional; D005260:Female; D014644:Genetic Variation; D007525:Isoelectric Focusing; D007782:Lactoglobulins / Q000737:chemistry* / Q000235:genetics / Q000302:isolation & purification; D013058:Mass Spectrometry; D008892:Milk / Q000737:chemistry*; D008894:Milk Proteins / Q000737:chemistry*; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000737:chemistry / Q000302:isolation & purification; D012680:Sensitivity and Specificity; D017384:Sequence Deletion; D014357:Trypsin; D000067816:Whey Proteins
D007782:Lactoglobulins; D008894:Milk Proteins; D010446:Peptide Fragments; D000067816:Whey Proteins; D014357:Trypsin