Custom Peptide Synthesis: an Overview

Our scientists understands the indispensable role of good peptides in your research.  They have tailored this new service to your diverse experimental needs.  The peptide synthesis program was originally established as a source of high quality antigens for our custom antibody services.  As a results, our team enjoys good experience in the synthesis of special (sometimes hard-to-make) peptides.  As a customer, you would benefit greatly from our expertise.

Scale and Purity

Depending on your intended application(s), our labs produce peptides on a milligram (mg) to kilogram (kg) scale, and with different purities (see Table 1 below).  All synthesized peptides are validated by both HPLC and mass spectroscopy.


Suitable Applications


antigens (polyclonals), antibody purification (polyclonals), ELISA.


antigens (polyclonals), antibody purification (polyclonals), ELISA, quantitative biochemical and enzymatic assays, affinity purification, cell attachment, Western blotting, electrophoresis.


antigens (monoclonals), quantitative biochemical assays (receptor binding, competitive binding, phosphorylation, proteolysis, enzymatic inhibition), structural biology, NMR, mass spec, other in vitro or in vivo studies.


pharmaceuticals, cosmetics, SAR, X-ray crystallography

Table 1.  Purity of Synthetic Peptides Recommended for Various Applications

Difficult Syntheses

As mentioned above, Li International would be your best choice if you need any of the hard-to-make peptides including but not limited to long peptides (>40 amino acids), proline- or glycine-rich, highly hydrophobic peptides and highly charged peptides.

Special Modifications

Our custom peptide service also provides a variety of modification options, as listed below:


Modification Options


Arg, Lys, Ser, Thr, Tyr, Cys (side chains) and backbone N


Lys and others


Ser, Thr, Tyr


acetylation and others


amidation, cystamidation, esteration and others


biotination, fluorescence labels

special amino acids

e.g., beta and gamma amino acids

protein conjugation

BSA, KHL, OVA and others

cyclization and disulfide bond

cyclic amide, thioester, lactone, disulfide bond linkage and others

Table 2.  A Non-Exclusive List of Modification Options for Custom Peptide Service 

Isotope-Labeled (Heavy) Peptides

We provide the following isotope labels:

    Leucine:  6 C13 atoms and 1 N15 atom, or 6 C15 atoms
    Valine:  5 C13 atoms and 1 N15 atom
    Glycine:  N15 atom
    Lysine:  C13 atoms and 2 N15 atoms
    Alanine:  3 C13 atoms and 1 N15 atom
    Arginine:  C13 atoms and 4 N15 atoms
    Proline:  5 C13 atoms and 1 N15 atom

Cost and Timeframe

We aim to supply you high-quality custom peptides in an expedient and cost-effective fashion.  Please feel free to contact us for quotes and evaluations.