Peptide synthesis and equipment

Chemical synthesis method of polypeptide:

Solid-phase synthesis method: In 1963, R.B. Merrifield established the solid-phase synthesis method of fixing the C-terminal of amino acid on an insoluble resin, and then successively condensation of amino acid, extension of peptide chain, and synthesis of protein on this resin. In the solid phase method, the purification purpose can be achieved by simply washing the resin after each step of reaction, which overcomes the difficulty of purification of each step of products in the classical liquid phase synthesis method, and lays the foundation for automatic peptide synthesis. For this reason, Merifield won the 1984 Nobel Prize in Chemistry.

After continuous development, the current solid phase method mainly refers to the Fmoc method, which uses resin as the solid phase carrier to covalently connect the protective amino acid to the solid phase carrier, and then remove its protective group, and then connect the second protective amino acid to the first amino acid, and repeat the reaction until the required peptide chain length is synthesized, and then release the peptide resin through the corresponding cracking reagent, and then get the high-quality product after purification and freeze-drying.

Advantages: It is used for the synthesis of medium and long peptides, and the purity of crude peptides is high
Disadvantages: high cost, large amount of solvent and small scale of synthesis

Peptide lyophilization and equipment

Freeze-drying of polypeptides: After the polypeptides are separated and purified by HPLC, most of the organic solvents and water are removed by the rotary evaporator, and then the polypeptides are lyophilized by the lyophilizer.

Preservation of lyophilized peptides:
It is better to store at - 20 ℃ under freezing conditions. If stored below - 10 ℃, most peptides can maintain their activity for several years.
When using frozen products, the bottle or test tube should be raised to room temperature in the drying box with fresh desiccant before opening the cap.

For products stored at - 20 ℃, this process takes one hour or more, depending on the size of the package.

Otherwise, when the bottle is opened, the water vapor will enter and cause the peptide to condense and reduce its stability. Once opened, it should be weighed quickly and sealed immediately to avoid deliquescence, especially for hydrophilic peptides.

Low-temperature freeze-drying equipment with milligram and kilogram vacuum