Stable Isotope-Labeled Peptides via Solid Phase Synthesis

Synthetic peptides are short chains of amino acids that can be custom-made for research and pharmaceutical applications. With precise control over peptide sequences, high-purity peptides are produced with defined isotope incorporation.

Incorporating stable isotope-labeled amino acids into peptides allows researchers to use techniques such as nuclear magnetic resonance (NMR) spectroscopy and mass spectrometry (MS) for wide ranging applications across proteomics, metabolic studies, and drug development.

Peptide therapeutics like semaglutide, a GLP-1 receptor agonist used for diabetes and weight management, benefit from such labeling strategies in drug development. Stable isotope labeling allows researchers to study peptide stability, improve formulation strategies, and optimize manufacturing processes. By leveraging SPPS with stable isotope labeled amino acids, scientists can produce high-purity peptides with defined labeling patterns, enhancing their application in both fundamental research and clinical drug development.

Synthesis of Labeled Synthetic Peptides

One of the most efficient ways to produce synthetic peptides is solid-phase peptide synthesis (SPPS), which allows stepwise construction of peptides while keeping them attached to a solid support.

A resin is often the solid support of choice for amino acid attachment and allows the peptide to ‘grow’ in a controlled, sequential manner without losing intermediates during the process. The first bound amino acid is chemically modified with a protecting group to prevent unwanted reactions at its reactive sites. Once bound, the protecting group is removed from the amino acid’s amine group to expose a reactive site (known as deprotection) and subsequent stable isotope-labeled amino acids are activated and coupled to the growing chain.

Silantes supplies protected stable isotope-labeled amino acids specifically designed for use in SPPS, with reagents designed to enable precise incorporation of mass-labeled residues at defined positions within the peptide sequence. When combined with SPPS, this approach allows researchers to create peptides with site-specific mass shifts, facilitating accurate studies of biomolecular pathways, enzyme-substrate interactions, and quantitative proteomics – especially valuable for mechanistic studies and biomarker discovery.

This coupling reaction is repeated – adding one amino acid at a time – and the peptide sequence is built precisely according to the desired structure. The isotopes present in the amino acid make them distinguishable from naturally occurring peptides in analytical studies.  After the full peptide sequence is assembled, it is cleaved from the resin using a strong acid and leaving the final free peptide and removing any remaining.

The crude peptide is then purified using HPLC to remove side products or incomplete sequences, whilst the purity and correct incorporation of isotope labels are confirmed to ensure the peptide meets the desired specifications for research or pharmaceutical applications

Advantages & Disadvantages

Solid phase peptide synthesis is a widely used method for producing peptides with high efficiency and control, with key advantages and disadvantages:

Advantages	Disadvantages
High precision in amino acid sequence assembly	Efficiency declines for peptides longer than 50 residues
Enables incorporation of stable isotope-labeled and non-natural amino acids	Some modifications may reduce synthesis efficiency
Rapid and automated process for reproducible synthesis	Limited scalability for larger peptides
No biological contaminants or unwanted post-translational modifications	Expensive protected amino acids, resins, and solvents
No need for living cells or bioreactors	Low yield for hydrophobic or aggregation-prone sequences
Suitable for hydrophilic peptides with simple sequences	High solvent consumption raises sustainability concerns.

While SPPS offers significant benefits in peptide production, selecting the right manufacturer is crucial to ensuring product quality, scalability, and cost-effectiveness.

Expanding Your Research Possibilities with Stable Isotope-Labeled Amino Acids

At Silantes, we offer a range of stable isotope-labeled protected amino acids designed for use in solid-phase peptide synthesis (SPPS). Click here to view our ever-expanding product portfolio for solutions of different types of research and goals.

Not sure what you need, or require additional help? Contact us and let us help you find the right solution for your research needs.