A protocol is presented for the determination of low-abundance biomarkers from dried serum samples exemplified with the biomarker progastrin-releasing peptide (ProGRP). Antibody-coated magnetic beads are used for the selective cleanup and enrichment of a proteotypic ProGRP peptide. The captured peptide is subsequently analyzed by liquid chromatography-tandem mass spectrometry.
Ngo, H. B., Oulie, I., Reubsaet, L., Halvorsen, T. G. Microsampling in Targeted Mass Spectrometry-Based Protein Analysis of Low-Abundance Proteins. J. Vis. Exp. (191), e64473, doi:10.3791/64473 (2023).