Mapping sites of protein phosphorylation by mass spectrometry utilizing a chemical-enzymatic approach: characterization of products from alpha-S1 casein phosphopeptides.
A novel chemical-enzymatic approach was developed to facilitate identification of phosphorylation sites in isolated phosphoproteins. ESI-TOF mass spectrometry was used to characterize products from the chemical-enzymatic cleavage of specific phosphorylation sites in bovine alpha-S1 casein and synthetic phosphopeptides containing substitutions at a single phosphorylation site. Further refinements to this approach for identification of protein phosphorylation sites and its utility for the quantification of phosphopeptides by isotope-dilution mass spectrometry are presented.
McCormick
Daniel J
DJ
Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA. mccormick.daniel@mayo.edu
Holmes
Michael W
MW
Muddiman
David C
DC
Madden
Benjamin J
BJ
D000595:Amino Acid Sequence; D000818:Animals; D002364:Caseins / Q000378:metabolism*; D002417:Cattle; D008969:Molecular Sequence Data; D010446:Peptide Fragments / Q000378:metabolism; D010748:Phosphopeptides / Q000378:metabolism*; D010766:Phosphorylation; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods*
D002364:Caseins; D010446:Peptide Fragments; D010748:Phosphopeptides