Lyophilisate: storage and stability in the laboratory
Freeze-dried peptides are comparatively stable, but not immune. Moisture, heat, light and oxygen are the four factors that matter.
Peptides are supplied as a lyophilisate, meaning freeze-dried. Removing the water slows most degradation reactions considerably. Stable, however, does not mean indefinitely shelf-stable.
The four influencing factors
| Factor | What happens | Countermeasure |
|---|---|---|
| Moisture | Hydrolysis, clumping | Keep the vial closed, let it reach room temperature before opening |
| Heat | Accelerates all degradation pathways | Store refrigerated |
| Light | Photo-oxidation, especially of Trp, Tyr | Store in the outer carton |
| Oxygen | Oxidation of Met, Cys, Trp | Do not open the vial unnecessarily |
Temperature
The label on our peptides states store refrigerated, max. 8 °C. For longer-term storage, research typically uses -20 °C. What matters most is consistency: frequent temperature changes cause more harm than steady, cool storage.
The most common mistake: condensation
A cold vial that is opened immediately draws in atmospheric moisture. This condenses on the powder. In the laboratory, therefore, always let the closed vial reach room temperature first.
Peptides in solution
Dissolved peptides are considerably less stable than the lyophilisate. Common laboratory practice:
- Aliquot solutions to avoid repeated freezing and thawing
- Store aliquots cold and protected from light
- Label each aliquot with lot number and date
Background
The fundamental degradation mechanisms such as deamidation, oxidation and aggregation are well described for peptides and proteins. A frequently cited review is Manning et al. (2010).