03 — In vitro
Reconstituting lyophilized peptides for laboratory assays
Lyophilized peptide is the stable form. Most avoidable loss happens in the hour after solvent is added.
Before opening
- Bring the closed vial toward room temperature in a desiccator or dry box so condensate does not wet the cake.
- Record batch, mass on the label, and target stock concentration in the notebook before adding liquid.
- Decide the aliquot plan now. Reconstituting an entire vial into one working bottle is how freeze–thaw damage starts.
Mass and concentration
Label mass is the starting figure. For quantitative work, confirm whether the CoA reports peptide content versus net weight. Document the basis used (net content versus as-is).
Physical handling
- Add solvent down the glass wall.
- Allow the cake to wet, then swirl. Do not vortex as a default.
- Inspect against light for optical clarity.
- Transfer to low-bind tubes if the peptide will be used at low concentration.
Working dilutions
Prepare a concentrated stock in the solvent that actually dissolves the sequence. Prepare working dilutions in the assay buffer on the day of the experiment when stability is unknown. This desk does not publish universal dilution tables.
Sterility and filtration
For cell-free analytical work, cleanliness and particulate control matter more than pharmaceutical sterility. Filter only if the method requires it and the peptide is not lost on the membrane. Single-use frozen aliquots are preferred over multi-day bench stocks.
Label immediately
Product identifier, batch, stock concentration and solvent, date and time reconstituted, preparer, storage location, discard rule.
General laboratory information for Research Use Only materials. Return to the desk.