Laboratory reconstitution guide
How to bring a lyophilised research peptide into solution for in-vitro work, and how to store the stock so every experiment uses equivalent material.
Research use only. For in-vitro laboratory research use only. Not for human or veterinary use.
Equipment
- Calibrated micropipettes and sterile, low-retention tips
- Diluent (see below), sterile and at room temperature
- Low-protein-binding microcentrifuge tubes for aliquots
- Laminar flow hood or clean bench; nitrile gloves; freezer labels
Protocol
- Equilibrate the vial. Let the sealed vial reach room temperature (about 20 minutes) before opening, so moisture doesn't condense on the hygroscopic powder.
- Collect the powder. Tap the vial or spin briefly so all powder sits at the bottom.
- Choose the diluent. Most peptides dissolve in sterile water or bacteriostatic water (0.9% benzyl alcohol, for multi-use stock). Basic or poorly soluble peptides often dissolve better in dilute (0.6%) acetic acid. Very hydrophobic sequences may need a small proportion of DMSO before dilution in buffer. Check the solubility note for your compound.
- Add diluent. Add the calculated volume with a calibrated pipette, running it down the inside wall of the vial rather than directly onto the powder. Use the concentration calculator to pick a volume.
- Dissolve gently. Swirl or roll the vial. Don't vortex or shake hard: shear and foaming can denature peptides. A clear solution with no particles indicates full dissolution.
- Aliquot and store. Split the stock into single-use aliquots, label each with the compound, batch code, concentration and date, then freeze.
Storage
| Form | Temperature | Typical stability |
|---|---|---|
| Lyophilised, sealed | −20 °C, dark, dry | Up to 24 months (see certificate) |
| Reconstituted stock, aliquoted | −20 °C or −80 °C | Weeks to months; avoid freeze–thaw |
| Reconstituted, in use | 2–8 °C | Days; bacteriostatic water extends this |
Quantitative work
A lyophilised peptide's nominal mass includes counter-ions and residual water, so net peptide content can be lower. Where exact concentrations matter, use the measured mass reported in the batch documentation supplied with your order and confirm the concentration analytically, for example by UV absorbance for sequences containing Trp or Tyr.