Peptide Bonds
ALL ARTICLES AND PRODUCT INFORMATION PROVIDED ON THIS WEBSITE ARE FOR INFORMATIONAL AND EDUCATIONAL PURPOSES ONLY. The products offered on this website are furnished for in-vitro studies only. In-vitro studies (Latin: in glass) are performed outside of the body. These products are not medicines or drugs and have not been approved by the FDA to prevent, treat or cure any medical condition, ailment or disease. Bodily introduction of any kind into humans or animals is strictly forbidden by law.
Peptide Storage
Proper storage of peptides is crucial to maintain their integrity and ensure reliable laboratory results. Whether peptides are susceptible to degradation or not, adhering to optimal storage practices can significantly prolong their stability and usability.
Upon receipt, peptides should be stored in a cold environment away from light. For short-term storage, refrigeration at temperatures below 4°C (39°F) is generally sufficient if the peptides will be used within days, weeks, or a few months. Lyophilized peptides can often remain stable at room temperature for several weeks or longer, making such storage adequate for short-term needs.
For longer-term storage extending from several months to years, storing peptides in a freezer at -80°C (-112°F) is preferable to maintain their stability effectively.
To prevent degradation, it is crucial to avoid subjecting peptides to repeated freeze-thaw cycles. Each cycle can compromise the integrity of the peptides, reducing their effectiveness in experiments. Moreover, it is advisable to refrain from using frost-free freezers for peptide storage, as temperature fluctuations during defrosting cycles can adversely affect peptide stability.
Preventing Oxidation and Moisture Contamination
Preventing contamination of peptides with air and moisture is crucial to maintaining their stability and integrity. Moisture contamination, in particular, can occur when using a peptide immediately after removal from the freezer. To mitigate this risk, allow the peptide to reach room temperature before opening its container to prevent moisture uptake from the air on the cold surface of the peptide or inside the container.
Additionally, minimizing a peptide’s exposure to air is essential. Keep the peptide container closed as much as possible, and after removing the required amount of peptide, promptly reseal the container under an atmosphere of dry, inert gas such as nitrogen or argon. This precaution helps minimize the risk of oxidation, which is especially critical for peptides containing cysteine (C), methionine (M), and tryptophan (W), as they are prone to air oxidation.
To preserve long-term stability and minimize degradation, many researchers opt to aliquot the required amount of peptide for each experiment into separate vials. This practice reduces the need for frequent thawing and refreezing, as well as exposure to air, thereby safeguarding the integrity of the peptide samples.
Storing Peptides In Solution
The shelf life of peptide solutions is notably shorter compared to lyophilized peptides, and peptides stored in solution are susceptible to bacterial degradation. Peptides containing specific amino acids such as Cys, Met, Trp, Asp, Gln, and N-terminal Glu in their sequences have particularly limited shelf lives when in solution.
However, if storing peptides in solution is unavoidable, it is recommended to use sterile buffers with a pH range of 5-6. Additionally, dividing the peptide solution into aliquots is essential to prevent repeated freezing and thawing, which can compromise stability. Peptide solutions typically remain stable for up to 30 days when refrigerated at 4°C (39°F). For peptides prone to instability, freezing is advisable when not in use to extend their shelf life.
Peptide Storage Containers
Containers used for peptide storage must meet several criteria to ensure the integrity and stability of the peptides. They should be clean, clear, and structurally sound, with chemical resistance being a crucial attribute. Additionally, containers should be appropriately sized based on the amount of peptide they will hold.
Glass and plastic vials are commonly utilized for peptide storage. Plastic vials are available in two main types: polystyrene and polypropylene. Polystyrene vials are typically clear but lack chemical resistance, whereas polypropylene vials are generally translucent yet offer chemical resistance.
Although glass vials provide optimal characteristics for peptide storage, peptides are sometimes shipped in plastic vials to prevent breakage during transit. However, peptides can be easily transferred between plastic and glass containers as needed.
Peptide Storage Guidelines: General Tips
When storing peptides, it’s important to adhere to the following guidelines:
- Store peptides in a cold, dry, and dark environment.
- Minimize repeated freezing and thawing cycles to maintain peptide integrity.
- Prevent overexposure to air by sealing containers tightly.
- Shield peptides from light exposure to prevent degradation.
- Refrain from long-term storage of peptides in solution, if possible.
- Aliquot peptides based on experimental needs to minimize degradation risk.