Storing research peptides the right way

Peptides are sensitive molecules. The way a lot is stored has as much influence on its usable life as the way it was made. The single biggest variable is whether the peptide is still in its dry, lyophilised form or has been reconstituted into solution.

Dry, lyophilised peptide

In its freeze-dried state a peptide is relatively stable. Kept sealed, cold and dark, many lyophilised peptides remain within specification for long periods. The enemies are moisture and heat.

• Keep the vial sealed until you are ready to use it.
• Store cold — refrigeration is fine for short-to-medium term; a freezer extends life for long-term storage.
• Keep it dark and dry; avoid the fridge door where temperature swings most.

Reconstituted peptide

Once a peptide is in solution the clock speeds up considerably. Water enables the very reactions — hydrolysis, oxidation, aggregation — that break peptides down.

• Refrigerate immediately after reconstitution.
• Use within the window appropriate to the specific sequence.
• Minimise warm-up and cool-down cycles; each one stresses the molecule.

Signs a lot may have degraded

Cloudiness, visible particles, or a solution that will not go fully clear on reconstitution are all reasons to stop and investigate rather than proceed. When in doubt, re-test or set the lot aside.