How to Reconstitute Lyophilized Peptides for Lab Use
Most research peptides ship as a freeze-dried powder. Reconstituting it carefully protects the material and keeps your experimental results consistent.
Why peptides are lyophilized
Lyophilization (freeze-drying) removes water from the peptide so it stays stable during shipping and storage. The material appears as a white powder or a small cake at the bottom of the vial.
Choosing a diluent
The right diluent depends on the peptide and the experiment. Sterile water and bacteriostatic water (sterile water with 0.9% benzyl alcohol as a preservative) are common choices for in-vitro work. Some hydrophobic sequences need a different solvent, so check the literature for your compound.
Bacteriostatic water is often chosen when a vial will be accessed more than once, because the preservative limits microbial growth between uses.
Technique
Let the vial reach room temperature before opening to reduce condensation. Wipe the stopper with an alcohol swab and work in a clean environment using sterile equipment.
Add the diluent slowly, aiming the stream down the inside wall of the vial rather than directly onto the powder. Swirl or roll the vial gently until the solid dissolves. Do not shake, since agitation can cause foaming and may degrade some peptides.
Calculate the resulting concentration from the stated peptide mass and the volume of diluent added, and record both in your lab notebook.
Labeling and storage after reconstitution
Label the vial with the compound, concentration, diluent, date and lot number. Reconstituted peptides are generally kept refrigerated at 2 to 8°C and protected from light. For longer storage, many labs aliquot and freeze to avoid repeated freeze-thaw cycles.
All Niho Labs materials are for laboratory research use only and are not for human consumption.