Concatemer Assisted Stoichiometry Analysis (CASA)

MS sequences each precursor peptide by selecting and breaking it into smaller fragments. An under appreciated feature is that these fragments are effectively the unique fingerprint of each precursor. By analyzing such fingerprint, targeted MS (PRM, MRM or SRM) turns a blind eye on potential interference to a precursor peptide, and measures it with vastly superior sensitivity, accuracy and precision. To enable this targeted approach, we have developed CASA to generate isotope-coded peptide standards. Such peptide standards are used to establish the fingerprints and enable protein quantification via isotope-dilution. This CASA technology is undergoing rapid and iterative optimizations through its applications to study specific biological questions. We are excited to share this technology openly with colleagues, stay tuned for updates and feel free to contact us for reagents.