Chemical Labeling

Isotopically labeled standards for proteomic measurements can be prepared chemically. This can be achieved at the peptide or protein level by solid phase synthesis or recombinant gene expression, respectively. To aid the synthesis of stable isotope-labeled peptides, CIL offers an array of protected amino acids and preloaded resins. For the expression of stable isotope-labeled proteins, we offer media as well as cell-free protein expression reagents and kits from CellFree Sciences. CIL also offers select full-length proteins (e.g., CRP, ubiquitin) for use in bottom-up LC-MS experiments. The synthesis/expression products are briefly described and referenced on their associated page.

Peptide Synthesis

Targeted MS analysis (i.e. selected reaction monitoring or SRM) is an alternative to antibody-based assays for the validation of clinically relevant biomarkers, but also has been employed for discovery-based proteomics.

Protein Expression and Standards

Stable isotope labeled cellular biomass can be used in both proteomic and metabolomic investigations. In addition, quantitative, proteomic MS-based studies can benefit greatly from the use of purified, labeled intact protein as internal standards. Read more