1.   How is the peptide transported and stored?

The synthesis of the polypeptide in the form of a lyophilized powder can be sealed and transported at normal temperature, but the polypeptide in a dissolved state is not suitable for long-term storage. In order to preserve the peptide for a long time, it is recommended to store it in a lyophilized powder in a sealed container containing desiccant. It can be stored at -20 ° C ( -80 ° C better) for several years while avoiding bacterial degradation and oxidation. The formation of secondary structures can be avoided.

Peptide synthesis tends to be highly hygroscopic, so it is recommended to operate quickly when weighed and store the remaining peptides at -20 ° C or lower. Polypeptides containing cysteine, methionine, tryptophan, asparagine, glutamine and glutamic acid N- terminus have a shorter shelf life than other polypeptides.

2. How does the peptide dissolve?

The solubility of polypeptide synthesis is highly dependent on the polarity of the polypeptide. The acidic polypeptide is dissolved in an alkaline solvent, and the basic polypeptide is soluble in an acidic solvent, and the hydrophobic polypeptide and the neutral polypeptide containing a large amount of uncharged polar amino acid residues or hydrophobic amino acids can be dissolved in a small amount of organic solvent. Such as DMSO , DMF , acetic acid, acetonitrile, methanol, propanol or isopropanol, and then diluted with water (distilled water). Polypeptides containing methionine or cysteine ​​cannot be dissolved in DMSO because DMSO may cause side chain oxidation.

Please try to preserve the synthetic polypeptide in the form of a lyophilized powder at -20 ° C (-80 ° C preferred), but dissolve well as to save the polypeptide, note dispensing sample into storage, to avoid repeated freezing and thawing. Each sample should be thrown away after it has not been used up. Bacterial degradation can sometimes become a problem with solution peptides, so dissolve the peptide in sterile water or directly filter the peptide solution ( 0.22 uM ) .

3. What is the purity of the peptide?

Polypeptide purity means the content of the target polypeptide is detected by HPLC at a wavelength of 214nm (214nm wavelength is absorbed the peptide chain), not UV spectrophotometer salts and residual water. In general, the purified polypeptide contains impurities which are modified by a sequence, such as a deletion sequence (a target sequence in which one or more amino acid residues are deleted), and a truncation sequence (a sequence generated in a capping process). Protection of incomplete sequences (produced throughout the synthesis process or the final cleavage process).

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