Targeted proteomic analysis allows for highly specific quantitation of a small number of individual proteins from complex matrices, such as tissues and biological fluids. In this approach, the target protein is digested with a protease, such as trypsin, either from a purified source or in silico, to discover a peptide or peptides that will be unique rreporters for that protein (these are sometimes referred to as ‘proteotypic’ peptides). An assay is then developed on a triple-quadrupole mass spectrometer in which only those peptides are detected. This allows the sample to be minimally fractionationated or enriched prior to analyzing for the protein of interest. Synthetic, isotopically labeled forms of the target peptides are spiked into the sample to serve as normalization standards and can yield relative abundances between samples, or absolute quantitative measurements for the protein of interest.
Developing a targeted quantitative proteomic assay takes place in a stepwise fashion, including evaluating peptides from the protein of interest, selecting the best responders, ordering synthetic, isotopically labeled peptides, and evaluation of the assay in-matrix for sensitivity. Development of an assay is most appropriate when there will be many samples and the matrix will be consistent across the different samples. Contact us for help in designing a targeted quantitative proteomic experiment, as these can be tricky to design but are also very satisfying to perform.
Our pricing is on a sample-by-sample basis and each requires digestion, solid-phase extraction, and the LC/MS/MS.
For the 4th sample and above, the LC/MS/MS drops to $112.50