Selective Reaction Monitoring (SRM) and Parallel Reaction Monitoring (PRM) Based Biomarker Assay Development


  • Antibody-free approach is applicable to any species.
  • 100% customer customisable.  Easily expanded to incorporate new target proteins
  • Stable isotope-labelled peptide standards facilitate accurate quantitation and enhanced reproducibility.
  • Option for enrichment of low abundance proteins using antibodies or chromatography.
  • By using an upfront top-14 abundance protein depletion stage, we can aim to deliver a lower LOD/LLOQ in serum/plasma.
  • Compatibility with a wide variety of sample matrices, including plasma, serum, cell lysates, CSF, exosomes etc.
  • Single or multiplex outputs up to 100 proteins and/or their PTM’s per assay.
  • Can measure 100’s of samples per week once developed.
  • Analysis package includes full computational proteomic analysis and bioinformatics covering extensive data interpretation, pathway analysis and biological relevance.
  • Easily converted to fit-for-purpose assays for non-clinical and clinical use.
  • Easily converted to fully validated assays for clinical use, under GCLP as required.

Once a fit for purpose peptide or protein panel is identified, we typically design a suitable Targeted SRM or PRM assay for validation and/or refinement that will generally be faster, more sensitive, and accurate than unbiased discovery experiments. SRM assays can also be developed or transferred into our certified GCLP environment if required for use in clinical trials.   

Proteome Sciences offers the benefit of allowing for considerable more proteins/protein PTM’s) to be analysed in a single experiment and the assay development is faster. SRM seldom can be used to quantitate more than 20 proteins in an assay.  Our best achievement in RM assay development is approx. 100 different phospho-protein sites being analysed in a single PRM assay.

Targeted assays do not require antibodies (though these may be useful for prior target enrichment), so assays can be developed for any protein (and most protein PTM) detected in a preliminary Discovery experiment or selected from literature. We can support target peptide selection based on our proprietary database of identified features from discovery experiments across a wide range of different species and sample types.

SRM assays are run on a triple quadrupole mass spectrometers and can be deployed in basic research through to phase III clinical studies requiring GCLP validated methods available at Proteome Sciences’ Frankfurt Laboratory.   PRM assays are run on a more advanced Orbitrap Mass Spectrometer and are currently only suitable for internal research use.

In both cases the use of a 13C/15N labelled heavy peptide standards allows absolute quantification of the protein of interest, often delivered at levels from 10 pg/ml and upwards. We offer a service whereby these peptide standards are identified, synthesised and then incorporated into the assay

Depending on your assay needs, SRM/PRM assays can come with whatever assay validation your project demands

  • The desired sensitivity
  • LOD, LLOQ, ULOQ validation
  • Dilutional linearity
  • Parallelism
  • Reproducibility run to run combined to different operators, different instruments, different days etc

Or, why not transfer your research SRM assay for full GCLP validation and deployment across clinical trials.