title: Antibody-based capture of target peptides in multiple reaction monitoring experiments.
abstract: Targeted quantitative mass spectrometry of immunoaffinity-enriched peptides, termed immuno-multiple reaction monitoring (iMRM), is a powerful method for determining the relative abundance of proteins in complex mixtures, like plasma or whole tissue. This technique combines 1,000-fold enrichment potential of antibodies for target peptides with the selectivity of multiple reaction monitoring mass spectrometry (MRM-MS). Using heavy isotope-labeled peptide counterparts as internal standards ensures high levels of precision. Further, LC-MRM-MS selectivity allows for multiplexing; antibodies recognizing different peptides can be added directly to a single mixture without subjecting to interferences common to other multiple antibody protein assays. Integrated extracted ion chromatograms (XIC) of product ions from endogenous unlabeled "light" peptide and stable isotope-labeled internal standard "heavy" peptides are used to generate a light/heavy peak area ratio. This ratio is proportional to the amount of peptide in the digestion mixture and can be used to estimate the concentration of protein in the sample.
authors.affiliation: Department of Medical Oncology, Erasmus MC Cancer Institute, Erasmus University Medical Center, Rotterdam, The Netherlands.
authors.forename: Tommaso
authors.initials: T
authors.lastname: De Marchi
authors.forename: Eric
authors.initials: E
authors.lastname: Kuhn
authors.forename: Steven A
authors.initials: SA
authors.lastname: Carr
authors.forename: Arzu
authors.initials: A
authors.lastname: Umar
mesh_terms: D013058:Mass Spectrometry / Q000379:methods; D010455:Peptides; D040901:Proteomics / Q000379:methods* / Q000592:standards
chemical_list: D010455:Peptides