Peptide Storage

Protecting compound integrity through proper storage and handling protocols.

FOR RESEARCH USE ONLY. This material is sold for laboratory research purposes only. Not for human consumption, veterinary use, or any diagnostic/therapeutic applications.

Peptide Storage: Maintaining Integrity and Activity

Proper storage is essential for preserving peptide integrity over time. Peptides are susceptible to chemical degradation through hydrolysis, oxidation, deamidation, and aggregation. Following appropriate storage protocols ensures that research materials remain viable for their intended experimental use.

Lyophilized (Powder) Storage

Lyophilized peptides are the most stable form and should be stored under the following conditions:

  • Temperature: Store at -20 degrees C or colder for long-term storage (months to years). Short-term storage (weeks) at 4 degrees C is acceptable
  • Moisture: Keep vials tightly sealed with desiccant. Moisture is the primary enemy of lyophilized peptides, as it can initiate hydrolysis and promote aggregation
  • Light: Store in amber vials or wrapped in foil. UV light can degrade tryptophan and other light-sensitive residues
  • Atmosphere: Ideally, store under inert gas (nitrogen or argon) to prevent oxidation of methionine and cysteine residues

Under optimal conditions (-20 degrees C, sealed, desiccated, dark), most lyophilized peptides remain stable for 2-5 years.

Reconstituted (Solution) Storage

Peptide solutions are significantly less stable than lyophilized powders:

  • Temperature: Store at -20 degrees C or -80 degrees C. Avoid repeated freeze-thaw cycles by preparing single-use aliquots
  • Buffer considerations: Use buffers that do not promote degradation. Phosphate buffers are generally suitable. Avoid Tris buffers for long-term storage, as primary amines can react with certain peptide sequences
  • Concentration: Higher concentrations (>1 mg/mL) tend to be more stable than dilute solutions, as the peptide is less susceptible to adsorptive losses to container surfaces
  • Container material: Use low-binding polypropylene tubes or silanized glass vials. Standard polystyrene and glass can adsorb significant amounts of peptide, particularly at low concentrations

Freeze-Thaw Considerations

Each freeze-thaw cycle can denature a fraction of the peptide through ice crystal formation, concentration effects at the ice-liquid interface, and pH changes. To minimize freeze-thaw damage:

  1. Prepare aliquots of the working concentration immediately after initial reconstitution
  2. Flash-freeze aliquots in liquid nitrogen or a dry ice/ethanol bath rather than slow-freezing in a standard freezer
  3. Thaw rapidly by warming to room temperature or using a 37 degrees C water bath briefly
  4. Never refreeze a thawed aliquot; discard any unused portion

Stability-Indicating Degradation

Signs that a peptide has degraded include:

  • Change in appearance (discoloration, gelation, or precipitation)
  • Loss of biological activity in functional assays
  • Broadened or shifted HPLC peaks upon re-analysis
  • New peaks appearing in mass spectrometry (deamidation adds +1 Da, oxidation adds +16 Da)

Special Considerations by Residue

  • Cysteine-containing peptides: Highly susceptible to oxidation. Store under inert atmosphere with reducing agents if disulfide formation is not desired
  • Methionine-containing peptides: Prone to oxidation to methionine sulfoxide. Minimize exposure to air and light
  • Asparagine/glutamine-containing peptides: Susceptible to deamidation, especially at elevated pH and temperature. Store at acidic pH when possible

Related Topics

For research use only. Not for human consumption. All products sold by Epiq Aminos are intended for laboratory research purposes only.