This article is part of the Journal of Mass Spectrometry special issue entitled “2nd MS Food Day” edited by Gianluca Giorgi.
MS-based characterization of αs2-casein isoforms in donkey's milk†
Article first published online: 11 SEP 2012
Copyright © 2012 John Wiley & Sons, Ltd.
Journal of Mass Spectrometry
Special Issue: 2nd MS Food Day
Volume 47, Issue 9, pages 1150–1159, September 2012
How to Cite
Saletti, R., Muccilli, V., Cunsolo, V., Fontanini, D., Capocchi, A. and Foti, S. (2012), MS-based characterization of αs2-casein isoforms in donkey's milk. J. Mass Spectrom., 47: 1150–1159. doi: 10.1002/jms.3031
- Issue published online: 6 SEP 2012
- Article first published online: 11 SEP 2012
- Manuscript Accepted: 15 MAY 2012
- Manuscript Revised: 8 MAY 2012
- Manuscript Received: 25 FEB 2012
- donkey milk;
- milk allergy;
The primary structure of four αs2-casein (CN) isoforms, present as minor components in the dephosphorylated CN fraction of a milk sample collected in Eastern Sicily from an individual donkey belonging to the Ragusano breed at middle lactation stage, was determined, using the known donkey's αs2-CN (GenBank Acc. No. CAV00691; Mr 26 028 Da) as reference. Proteins, with experimentally measured Mr of 25 429, 21 939, 25 203 and 21 713 Da, were isolated by the combined use of reversed-phase high-performance liquid chromatography (RP-HPLC) and two-dimensional polyacrylamide gel electrophoresis. The major spot of each gel, corresponding to a single protein, was digested by trypsin, α-chymotrypsin and endoproteinase Glu-C. The resulting peptide mixtures were analyzed by matrix-assisted laser desorption/ionization time-of-flight mass spectrometry and capillary RP-HPLC/nano-electrospray ionization tandem mass spectrometry, and the data obtained were used for the sequence determination. The isoforms are produced from differential splicing events involving exons 4, 5 and 6 and parts of the exon 17. Copyright © 2012 John Wiley & Sons, Ltd.