Every researcher should know and understand how to handle the various types of peptides they will be dealing with. If you get your peptides from verified vendors, then the shipping will always include a user manual from the manufacturer and it is highly recommended to read it in order to understand the specifics of handling that particular peptide.
To give you some insights, here are guidelines on how to handle and store some of the peptide types:
Guidelines for lyophilized peptides
The stability of every peptide is unique and will be contingent upon its sequence. For lyophilized peptides, the recommended storage should be at -20 degrees Celsius and away from bright light. These peptides will remain stable for several years if kept under these conditions, but it should be noted that there are certain amino acid residues in the peptides, which may affect long term stability if kept under these conditions.
Peptides whose sequences contain Met, Trp, or Cys residues have a tendency of being oxidized and as such, they should be stored under anaerobic conditions to ensure their stability. Peptides with Glu, Asp, Arg, His or Lys have a tendency of absorbing moisture from the atmosphere and they should thus be stored in a desiccator in a tight vial.
Guidelines for peptides in solution form
Peptides in solution form usually have a very limited shelf-life. Additionally, these peptides are susceptible to bacterial degradation, so storage in solution form is never a good idea in most cases. However, if storage can’t be avoided, then sterile buffers at a pH level between 5 – 6 should be used to dissolve the peptides, with the solutions divided into aliquots before being stored at a temperature below -200C. Freeze-thaw cycles should be avoided with these aliquots, as this will result in the quick degeneration of the peptides.