Defined heavy labels (13C/15N/D) and TMT6 options for quantitative LC-MS/MS, method validation, and structural analysis workflows.
Stable isotope-labeled (SIL) peptides—also referred to as isotope-labeled peptides or heavy isotope-labeled peptides—incorporate ^13C, ^15N, and/or deuterium (D) at defined amino acid residues to introduce a predictable mass shift (Δm) without altering the peptide sequence. In LC-MS/MS workflows, the labeled (heavy) peptide closely matches the chromatographic behavior of the native (light) peptide while remaining distinguishable by mass, enabling accurate and reproducible quantitation.
Bio-Synthesis synthesizes SIL peptides as matched light/heavy pairs using ^13C/^15N or deuterium labeling, with optional TMT6 channels for multiplexed analysis. Peptides are delivered LC-MS/MS-ready with purification, analytical QC, and certificates of analysis (COA) to support absolute quantitation and structural analysis workflows.
Stable isotope-labeled peptide standards supplied by Bio-Synthesis, Inc. (Lewisville, TX) have been reported in peer-reviewed Molecular & Cellular Proteomics literature for targeted quantitative proteomics applications.
Same sequence and chemistry; a controlled mass shift (Δm) enables absolute or relative quantitation.
Figure: Color SIL peptide standard workflow—matched light/heavy peptides with a defined mass shift (Δm) enable robust LC‑MS/MS quantitation.
Related: Isotope-Labeled Peptides, Peptide Modifications, Click Chemistry Peptides. If your sequence is challenging, see difficult peptide synthesis. For quick turnaround, browse ready-made catalog peptides.
Use this table to copy/paste the exact label keyword you want in your quote request. Mass differences are the nominal heavy–light shifts for the labeled residue or tag. Final peptide mass and labeling confirmation are reported on the COA.
Tip: if your assay uses trypsin, heavy Lys/Arg are often the default internal-standard choices. For multiplexed workflows, specify the desired TMT6 channel in your quote request.
SIL peptides are commonly used to turn a structural readout into a quantitative readout.
When your goal is resonance assignment or simplified spectra, heavy labeling can be useful.
Tell us the technique (NMR, MS, HDX, crosslinking) and the acceptance criteria; we’ll align the label plan to it.
Heavy peptide spikes provide known amounts to convert MS signal into concentration.
MRM/SRM and PRM assays rely on matched heavy internal standards.
Use SIL peptides to validate identification and quantify performance across runs.
Tandem mass tags enable multiplexed relative quantitation; specify channel in your request.
SIL peptides are used as system suitability checks and internal QC controls.
Stable isotope labeling is frequently combined with chemical modifications to create application-ready standards. Share your target workflow (enrichment, digestion, immuno-capture, click, etc.) and we’ll propose a synthesis and QC plan.
See also: Peptide Modifications and Click Chemistry Peptides.
Project-dependent add-ons can be aligned to your assay sensitivity and regulatory context.
Yes. SIL peptides are commonly used as internal standards because the heavy peptide closely matches the native (light) peptide’s chemistry and retention while differing by a defined mass shift (Δm), enabling robust LC–MS/MS quantitation.
For tryptic peptides, heavy Lys and/or Arg labels are commonly used so the heavy residue appears at the C-terminus after digestion. If you share your protease and peptide list, we’ll recommend the most robust label plan.
Yes. Matched light/heavy pairs are frequently used for assay development, standard curves, and inter-run normalization.
It can, depending on sequence and LC conditions. If retention matching is critical, 13C/15N labels are often preferred.
Yes. We can provide peptides with TMT6-126 through TMT6-131 N-terminal tags (project-dependent). Specify channel and any additional modifications.
For quantitative standards, higher purity reduces interference. Many targeted MS assays use ≥95% purity; some applications accept lower purity with appropriate characterization. Tell us your detection limits and matrix and we’ll recommend a practical target.
Yes. SIL phosphopeptides and other modified standards are supported (project-dependent). Include the exact modification site(s) and any enrichment step (IMAC/TiO2, antibodies) so we can align synthesis and QC.
For the fastest quote, send your peptide sequence(s) and any modifications, your preferred label keyword (copy from the enrichment table above), quantity (mg) and purity target, intended application (AQUA/MRM/PRM/DIA/TMT/structural analysis), and any required enrichment specification. We’ll respond with feasibility notes, a recommended synthesis/QC plan, and pricing.
What happens next: Our technical team reviews your request and replies with recommended labeling strategy, purification/QC plan, and delivery format aligned to your assay.
References for stable isotope-labeled peptides, absolute quantitation, and multiplexed tagging in proteomics.
References are provided for background. Bio-Synthesis does not claim ownership of the cited works.
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