title: Peptide and protein quantitation by acid-catalyzed 18O-labeling of carboxyl groups.
abstract: We have developed a new method that applies acidic catalysis with hydrochloric acid for (18)O-labeling of peptides at their carboxyl groups. With this method, peptides get labeled at their C-terminus, at Asp and Glu residues, and at carboxymethylated cysteine residues. Oxygen atoms at phosphate groups of phosphopeptide are not exchanged. Our elaborated labeling protocol is easy to perform, fast (5 h and 30 min), and results in 95-97 atom % incorporation of (18)O at carboxyl groups. Undesired side reactions, such as deamidation or peptide hydrolysis, occur only at a very low level under the conditions applied. In addition, data analysis can be performed automatically using common software tools, such as Mascot Distiller. We have demonstrated the capability of this method for the quantitation of peptides as well as for phosphopeptides.
authors.affiliation: Core Facility Proteomics, Center for Biological Systems Analysis (ZBSA), Habsburger Strasse 49, 79104 Freiburg, Germany.
authors.forename: Erik
authors.initials: E
authors.lastname: Haaf
authors.forename: Andreas
authors.initials: A
authors.lastname: Schlosser
mesh_terms: D000143:Acids / Q000737:chemistry*; D000595:Amino Acid Sequence; D002384:Catalysis; D002853:Chromatography, Liquid; D008969:Molecular Sequence Data; D010103:Oxygen Isotopes / Q000737:chemistry*; D010455:Peptides / Q000032:analysis*; D011506:Proteins / Q000032:analysis*; D053719:Tandem Mass Spectrometry
chemical_list: D000143:Acids; D010103:Oxygen Isotopes; D010455:Peptides; D011506:Proteins