title: From relative to absolute quantification of tryptic peptides with tandem mass tags: application to cerebrospinal fluid.
abstract: Quantification is a major task in proteomics. Among the different analytical strategies to enable peptide and protein quantification, tagging with isotopic labels has emerged as a practical, versatile, and efficient alternative. In particular, isobaric labels, such as TMT or iTRAQ, are now widely employed to make relative comparison of the protein amounts in separate biological samples with tandem mass spectrometry (MS/MS). We used herein a shotgun proteomic approach based on labelling with tandem mass tags (TMTs) for the relative quantification of proteins, and the absolute quantification of their tryptic peptides in human cerebrospinal fluid (CSF). First, the comparison of ante- and post-mortem CSF samples was carried out for the discovery of protein marker candidates of brain-damage disorders. Second, tryptic peptides representative of these candidates were measured in CSF using reporter-ion calibration curves. These works highlighted the advantages and limitations of such strategies for quantification purposes in proteomics.
authors.affiliation: Biomedical Proteomics Group, University of Geneva, CH-1211 Geneva 4.
authors.forename: Loïc
authors.initials: L
authors.lastname: Dayon
authors.forename: Natacha
authors.initials: N
authors.lastname: Turck
authors.forename: Alexander
authors.initials: A
authors.lastname: Scherl
authors.forename: Denis F
authors.initials: DF
authors.lastname: Hochstrasser
authors.forename: Pierre R
authors.initials: PR
authors.lastname: Burkhard
authors.forename: Jean-Charles
authors.initials: JC
authors.lastname: Sanchez
mesh_terms: D000595:Amino Acid Sequence; D015415:Biomarkers / Q000134:cerebrospinal fluid; D001927:Brain Diseases / Q000134:cerebrospinal fluid*; D002555:Cerebrospinal Fluid / Q000737:chemistry; D006801:Humans; D008969:Molecular Sequence Data; D010455:Peptides / Q000134:cerebrospinal fluid*; D040901:Proteomics / Q000379:methods*; D021241:Spectrometry, Mass, Electrospray Ionization / Q000379:methods; D019032:Spectrometry, Mass, Matrix-Assisted Laser Desorption-Ionization / Q000379:methods; D053719:Tandem Mass Spectrometry / Q000295:instrumentation / Q000379:methods*; D014357:Trypsin / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D010455:Peptides; D014357:Trypsin