Two-dimensional gel electrophoresis/matrix-assisted laser desorption/ionisation mass spectrometry of a milk powder.
Proteins in a commercial milk powder have been separated by two-dimensional gel electrophoresis and analysed by matrix-assisted laser desorption ionisation mass spectrometry. The mass spectrometric analyses were conducted in two steps: analysis of the intact proteins following their passive extraction into a suitable solvent mixture and analysis in reflectron mode of in situ digests of a number of gel spots. The combination of the two methods allowed a reliable identification of a number of proteins, including nine caseins as well as certain protein modifications including single/multiple phosphorylation, lactose-protein conjugates and Coomassie Brilliant Blue adducts. Analyses of the intact proteins prior to their in situ digestion contributed to a more efficient and reliable consultation of protein databases.
Galvani
M
M
GlaxoWellcome Medicines Research Center, via Fleming 4, Verona, Italy.
Hamdan
M
M
Righetti
P G
PG
D000818:Animals; D003611:Dairy Products / Q000032:analysis*; D015180:Electrophoresis, Gel, Two-Dimensional; D006868:Hydrolysis; D008892:Milk / Q000737:chemistry*; D010455:Peptides / Q000737:chemistry; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization
D010455:Peptides