Stable Isotope Labeled Peptides

Stable isotope labeled peptides, or SIL peptides, maintain identical amino acid sequence with the natural ones released from the parent proteins by chemical or enzymatic cleavage, but some of the amino acid residuals are labeled by specific stable isotope, such as 2H, 13C, and/or 15N atom(s).

Stable isotope labeled peptides have been widely applied in the nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS). The combination of SIL peptides with NMR spectroscopy allow for the incorporation of NMR active nuclei which can reduce the complexity of spectra, and then help researchers to obtain novel correlations between atoms for more structural information. Meanwhile, the utilization of SIL peptides in quantitative proteomics can facilitate the comparison of different proteomes, and protein-protein interaction studies as internal standards, even MRM/SRM-based absolute quantification of specific target proteins in biological samples. This AQUA strategy, is quite useful in protein therapeutics discovery, pharmacokinetics, and toxicity studies, etc.

Stable Isotope Options

With more than 10 years of experience, and as a world-leading peptide manufacturing organization, NovoPro can provide customized peptides labeled with stable isotopes including 2H, 15N & 13C, respectively, or a combination of 15N & 13C. Even when the peptides are attached with specific modification motifs.

  • 2H(deuterium)
  • 15N
  • 13C
  • 15N and 13C combinations

Below lists is the most common stable isotopically labeled amino acids that can be used for the synthesis of peptides with stable isotopes containing carbon 13 (13C), Nitrogen 15 (15N).

AminoAcid Code Isotope MassDifference Isotopicenrichment
Alanine Ala(A) U-13C3, U-15N +4Da >99%
Arginine Arg(R) U-13C6, U-15N4 +10Da >99%
Isoleucine Ile(I) U-13C6, U-15N +7Da >99%
Leucine Leu(L) U-13C6, U-15N +7Da >99%
Lysine Lys(K) U-13C6, U-15N2 +8Da >99%
Phenylalanine Phe(F) U-13C9, U-15N +10Da >99%
Proline Phe(p) U-13C5, U-15N +6Da >99%
Valine Val(V) U-13C5, U-15N +6Da >99%

Characteristic Features

  • Design & synthesis of your peptides with expected mass difference by applying specific stable isotope-labeled amino acids;
  • Easy and efficient quantification of the natural peptide by MS assay;
  • Free of radioactive hazard;
  • Possible assorted modifications such as disulfide bond formation;
  • Quick analysis of biological samples with swift preparation proposals;