Synthesizing a 132-mer peptide with high purity

Using a CSBio research scale peptide synthesizer, we share a case study of how a 132-mer peptide can be synthesized with high purity



Synthesis of peptides at any length requires extreme attention to detail for accuracy and purity of the desired compound. Correctly synthesizing peptides of 50 mer length is difficult, over 100 mer length is a remarkable feat. CSBio’s fully automated instruments are purposefully designed to maximize resin and solvent interaction while maintaining a clean system throughout the synthesis protocol, making it possible to consistently synthesize peptides containing over 130 amino acids at very high purities.


The chemists in CSBio’s in-house cGMP peptide manufacturing facility were tasked with making a cyclic peptide 132 amino acids in length containing a Cysteine to Cysteine disulfide bond linking the 39th and 79th amino acids.

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132 AA peptide sequence (protected)

Using a research scale CSBio peptide synthesizer, Fmoc protected amino acids were attached one by one in a stepwise fashion. Engineering decisions such as 180° inversion mixing as well as dedicated lines to separate the delivery of amino acids and piperidine ensure more resin to solvent interaction than nitrogen bubbling, vortex or oscillation mixing, while also maximizing coupling with no risk of chemical cross contamination.

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CSBio CS136X

Upon peptide synthesis completion the resin was cleaved giving the chemist’s 620mg of crude at 75% purity. A portion of the crude (220mg) was loaded into a 1” C18 HPLC column, cyclization of the fractions was performed using an iodine.  Post purification the chemists were able to extract 18mg of the re-purified disulfide peptide which tested at 98.7% purity. Resulting in an 8.2% yield from crude for a compound whose molecular weight was >15000g/mol.

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132mer post-purification chromatogram


CSBio synthesizers are designed to deliver the user with the highest crude quality for any possible peptide. As the only automated synthesizer manufacturer that produces cGMP peptides, constant collaboration of in-house chemists and engineers during the design process enables CSBio to improve synthesis results compared to industry competitors; making CSBio synthesizers the most robust and reliable instruments on the market for synthesis of any peptide.

Interested in our research scale peptide synthesizers? Get in touch with us.


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About Us

CSBio is a leading peptide and instrumentation manufacturing company located in Silicon Valley, California.

CSBio provides nonGMP and cGMP peptides, peptide APIs, research scale peptide synthesizers, commerical scale peptide synthesizers, DNA/RNA oligonucleotide synthesizers, and preparative HPLC purification equipment.

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