title: Mapping sites of protein phosphorylation by mass spectrometry utilizing a chemical-enzymatic approach: characterization of products from alpha-S1 casein phosphopeptides.
abstract: 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.
authors.affiliation: Department of Biochemistry and Molecular Biology, Mayo Clinic College of Medicine, Mayo Clinic, Rochester, Minnesota 55905, USA. mccormick.daniel@mayo.edu
authors.forename: Daniel J
authors.initials: DJ
authors.lastname: McCormick
authors.forename: Michael W
authors.initials: MW
authors.lastname: Holmes
authors.forename: David C
authors.initials: DC
authors.lastname: Muddiman
authors.forename: Benjamin J
authors.initials: BJ
authors.lastname: Madden
mesh_terms: 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*
chemical_list: D002364:Caseins; D010446:Peptide Fragments; D010748:Phosphopeptides