Handling of Peptides

How are peptides synthesized?

With very few exceptions, most peptides at Sinopep are synthesized using chemical methods. The source of each peptide—synthetic or recombinant—is clearly indicated in the product description, with recombinant products explicitly designated as recombinant peptides (rec).

Sinopep’s peptides are produced by chemical peptide synthesis, in which amino acids are assembled stepwise from the C-terminus to the N-terminus. Depending on the sequence and application, peptides are manufactured using solid-phase peptide synthesis (SPPS), liquid-phase (solution-phase) synthesis, or hybrid approaches that combine both methods. These complementary strategies allow efficient production across a wide range of peptide lengths and complexities.

What is the difference between 'research- and GMP-grade' peptides or oligonucleotides?

Research-grade peptides are strictly for laboratory and research use only and are not intended for human or therapeutic applications. GMP-grade APIs, by contrast, undergo rigorous monitoring for chemical and biological contaminants to ensure safety and suitability for human use.

How do you ensure peptide purity and quality?

Our CGMP specifications and testing procedures include the following:

  • Appearance: Solid, off-white to white
  • Solubility: Clear solution at specified concentration
  • Purity (HPLC/UPLC): 95–98% (phase-dependent)
  • Molecular Weight (MS) / AAA: Within ±10% of theoretical value
  • Peptide Content: ≥70%
  • Counter-Ion Content: Report
  • Elemental Impurities (ICP-MS): Report Sb, As, Bi, Cd, Cu, Pb, Hg, Mo, Ag, Sn
  • Endotoxin: Report LAL (Gel Clot) per USP
  • Bioburden: Report aerobic and spore counts per USP
  • Residual TFA: ≤0.1%
  • Residual Solvents: GC-MS, report
  • Moisture (Karl Fischer): ≤10%