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Stable Isotope Labeling Peptide Service

Stable isotope labeled peptides (SIL peptides), also known as heavy peptides, are peptides formed by amino acids with substitution of certain atoms. Thus, 12C can be replaced by 13C, 14N by 15N and 1H by 2H.

Stable isotope labeled peptides demonstrate identical chemical and physical properties. They behave in the same manner as non-labeled peptides, they only differ by mass.
Thanks to this delta mass, SIL peptides are useful in quantitative proteomics for relative protein quantification. Such as ICAT (Isotope Coded Affnity Tags) and iTRAQ (isobaric Tags for Relative and Absolute Quantifcation). SIL are also useful for absolute protein quantification applications MRM (Multiple Reaction Monitoring) and AQUA (Absolute QUAntification of proteins). And NMR studies and mass spectrometry techniques based on their well-defined increase in molecular weight compared to the native peptide.

SB-PEPTIDE offers a peptide synthesis services dedicated to proteomic quantification:

  • Individual stable isotope labeled peptides including long or complex sequences (c.f. table 1). Synthesis scale: starting from 1 mg, 2 mg, 5 mg and over. Purity rate >80%, >90%, >95%, >97%, >98%, >99%. Most common labelling are N-ter or C-ter K(13C 15N) or R(13C 15N). Other positions or amino acids can be considered.
  • Modified peptides with Cys CAM, Met OH, phosphorylation…
  • Customized aliquoting, delivered in lyophilized form.
  • Amino acid analysis AAA for absolute quantification available in option.


Discover our catalog of stable isotope labeled peptides here.

Our 10 days express service is applicable on the synthesis of isotope labeled peptides, contact us to check if your peptides are eligible.


Stable isotope labeled peptide

Table of mass shift for each 13C / 15N SIL amino acid