To ensure the stability of the peptides in the medium and long term, both their handling and storage must be done under certain conditions that avoid their degradation.
In this post we tell you how to store the peptides to maximize their useful life, both in the case they are lyophilized, and when they are in solution.
How To Store Lyophilized Peptides
As a general rule, lyophilized peptides are stable at room temperature for several weeks, so if they are intended for use within this time interval, they can be stored at room temperature or refrigerated at + 4ºC. In this case it is very important to keep them away from strong light sources.
For periods longer than 4 weeks, it is recommended to freeze them at -20ºC or -80ºC to avoid bacterial degradation, oxidation and the formation of secondary structures.
On the other hand, the sequence that makes up each peptide is one of the factors that most directly influences their stability, therefore the following considerations should be taken into account:
- Peptides containing Cys, Met or Trp : they are especially sensitive to oxidation phenomena, so they must be stored under anaerobic conditions.
- Peptides containing Asp, Glu, Lys, Arg or His : tend to absorb moisture from the environment, so they must be stored in a desiccator inside a hermetically sealed vial.
How To Store Peptides In Solution
The stability of the peptides in solution is much more limited than that of the lyophilized peptides, very especially in those cases that contain Cys, Met, trp, Asp, Gln and / or Glu N-terminal.
As a general rule, they are usually stable for 1-2 weeks at + 4ºC, for 3-4 months at -20ºC and for a maximum of one year at -80ºC.
General recommendations :
- Use sterile buffers at pH 5-6
- Aliquot peptides in solution to avoid freeze / thaw cycles
- Pass the solution through a 0.2um filter to eliminate potential bacterial contamination