title: Protein quantification by selective isolation and fragmentation of isotopic pairs using FT-ICR MS.
abstract: Isolation of tryptic peptide ions, along with their differentially labeled analogs derived from an artificial QconCAT protein, is performed using multiple correlated harmonic excitation fields in an FT-ICR cell. Simultaneous fragmentation of the isolated unlabeled and labeled peptide pairs using IRMPD yields specific y-series fragment ions useful for quantification. The mass increment attributed to stable isotope labeling at the C-terminus is maintained in the C-terminal fragment ions, providing multiple measurements of labeled/unlabeled intensity ratios during highly selective detection. The utility of this approach has been demonstrated in the absolute quantification of components of an unfractionated chicken muscle protein mixture.
authors.affiliation: Michael Barber Centre for Mass Spectrometry, School of Chemistry and Manchester Interdisciplinary Biocentre, University of Manchester, Manchester, United Kingdom.
authors.forename: Hannah
authors.initials: H
authors.lastname: Johnson
authors.forename: Stephen C C
authors.initials: SC
authors.lastname: Wong
authors.forename: Deborah M
authors.initials: DM
authors.lastname: Simpson
authors.forename: Robert J
authors.initials: RJ
authors.lastname: Beynon
authors.forename: Simon J
authors.initials: SJ
authors.lastname: Gaskell
mesh_terms: D000818:Animals; D002247:Carbon Isotopes / Q000737:chemistry; D002645:Chickens; D017357:Cyclotrons; D018482:Muscle, Skeletal / Q000737:chemistry; D009587:Nitrogen Isotopes / Q000737:chemistry; D010455:Peptides / Q000737:chemistry*; D021241:Spectrometry, Mass, Electrospray Ionization; D017550:Spectroscopy, Fourier Transform Infrared / Q000379:methods*; D053719:Tandem Mass Spectrometry; D014357:Trypsin / Q000737:chemistry
chemical_list: D002247:Carbon Isotopes; D009587:Nitrogen Isotopes; D010455:Peptides; D014357:Trypsin