The common problems and solutions in peptide synthesis process include the following aspects:
Peptide content: Peptide content refers to the percentage of peptide substances in a sample relative to non peptide substances. In peptide products, in addition to the peptide itself, non salt components introduced during the production process, such as water, absorbed solvents, coordination ions, and salts, are also included
Chemical stability:
Deamidation reaction: Asn/Gln residues are easily hydrolyzed to form Asp/Glu.
Hydrolysis: Peptide bonds in peptides are easily broken by hydrolysis, especially those formed by Asp participation, especially Asp Pro and Asp Gly peptide bonds.
Racemization reaction: All amino acid residues except Gly have chiral alpha carbon atoms and are prone to racemization reaction under alkaline catalysis. Asp residues are most prone to racemization reactions.
β - elimination degradation: Cys, Ser, Thr, Phe, Tyr and other residues can all be degraded through β - elimination, which is more likely to occur at alkaline pH and is affected by temperature and metal ions
Physical stability:
Denaturation, adsorption, aggregation or precipitation: Peptide denaturation is usually related to the destruction of the tertiary and secondary structures. In the denatured state, peptides are more prone to chemical reactions and their activity is difficult to recover. The intermediate formed during the denaturation process has low solubility and is prone to aggregation and precipitation
preservation:
Best storage conditions: Peptides are generally stored in the form of freeze-dried powder, which is very stable at -20 ℃, especially after freeze-drying and stored in a -20 ℃ dryer. Most peptides can be stored at this temperature for several years without change. To reduce the impact of humidity, freeze-dried peptides should be restored to room temperature under dry conditions before being exposed to air.
Packaging: Hesheng Biotechnology recommends small packaging to avoid repeated freeze-thaw cycles, reduce the number of container openings and closures, thereby reducing the chances of improper handling or bacterial contamination, and ensuring the stability of peptides
Purity testing:
Purity guarantee: All delivered peptides have reached the required purity, and peptides that do not meet the standard will be discarded. The HPLC and MS detection results can verify the purity and molecular weight of the peptide, while displaying the main impurities.
Other detection methods, such as amino acid analysis or elemental analysis, can confirm the amino acid composition of peptides as a supplementary means of peptide confirmation
Synthesis technology:
Solid phase peptide synthesis: Solid phase peptide synthesis does not require purification of intermediate products, allowing for continuous synthesis processes and laying the foundation for the automation of peptide synthesis. Based on Fmoc chemical synthesis, the target peptide was synthesized by covalently linking the carboxyl group of the C-terminal amino acid with an insoluble polymer resin, and then starting from the amino group of the amino acid
The above content summarizes common problems and countermeasures in peptide synthesis, covering multiple aspects such as chemical stability, physical stability, storage conditions, purity testing, etc.