Promise Proteomics SIL proteins for LC-MS/MS

A stable isotope labelled (SIL) form of an analyte protein is widely regarded as the optimal internal standard (IS) for absolute quantification of proteins using LC-MS; SIL proteins are often cited as the ‘gold standard’ IS.

The benefit of using a SIL protein as an internal standard is that it shares the same physiochemical behaviour as the target protein analyte. This means that the IS can be introduced at the start of the sample preparation workflow and will be processed along with the analyte protein throughout the entire analytical procedure. The addition of SIL-proteins at the start of the sample extraction can control for variations due to immunoaffinity or other isolation techniques, enzymatic digestion, other pre-analytical treatments as well as the LC and mass spectrometric ionisation. EMA guidelines recommend the use of a SIL-protein IS whenever possible for LC-MS/MS methods.

Promise Advanced Proteomics’ range of SIL proteins is offered as stable isotope labelled (and unlabelled) full-length recombinant proteins that are suitable for biomarker evaluation and validation, development of certified reference materials, pharmacokinetics studies of biotherapeutics and quantification of therapeutic monoclonal antibodies.