Figure 1. Quantitation by tandem-MS of amino acid stable isotope labeling of newly synthesized proteins.
(a) Trypsin fragments of the protein are separated and concentrated using liquid chromatography before mass spectrometry for detection and quantification of both labeled and unlabeled fragments using MS/MS ions. (b) Diagram of quantitation of labeled and unlabeled Aβ17-28 and graph of labeling curve to calculate synthesis and clearance rates of proteins.