Targeted Proteomics

What is targeted proteomics?

We offer both Parallel Reaction Monitoring (PRM) and Selected Reaction Monitoring (SRM) techniques. SRM and PRM are comparable in principle, and both are suited for quantifying multiple proteins in complex biological matrices. In both PRM and SRM, analysis begins when the peptides are sent into the first quadrupole mass analyzer (Q1), where the precursor (peptide) ion of interest is isolated. This population of precursor ions is then further fragmented in the collision cell (q2). In SRM, the newly fragmented ions then enter Q3, another quadrupole mass analyzer, wherein a small subset of sequence-specific ions are analyzed and an output of spectra is generated. Conversely, in PRM, the fragmented ions enter an Orbitrap mass analyzer, wherein all product ions are detected and scanned, generating MS/MS spectra which can then be quantified.

SRM and PRM

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Off-the-shelf SRM panel

We offer custom and off-the-shelf targeted SRM assay to monitor panels of plasma and human cerebrospinal fluid proteins. Our in-house informatics pipeline and DIA to SRM capability can save cost and time for your targeted assay method development. To be analytically rigorous, we verify every target in our off-the-shelf SRM assay in plasma and CSF to ensure precision and reproducibility within batches and between days. To provide a frame of reference, we implement external reference calibrators and external quality controls in each batch. We also spike in heavy labeled or distinct yeast protein before digestion and heavy labeled peptides after digestion in each sample to ensure data quality across sample groups as they are run on the instruments.

Our workflow

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Cost breakdown

infographic + link to downloadable excel sheet