Peptides
Peptides, in common with other biological materials, are best stored as cold and dry as possible. Individual peptides will vary in their stability but for those peptides for which no stability information is available to influence the choice of storage conditions, storage as lyophilised solids at -20° is advisable. Dye labelled peptides should be stored in the dark.
If it is anticipated that the peptide will be used over a period of several months it may be appropriate to divide the peptide into smaller quantities. This will allow the peptide to be used without the need to remove all of the material from storage each time some is required. The peptide can be divided by weight or, alternatively, if the peptide is to be used in solution it may be appropriate to dissolve the bulk in water and then split this solution down into smaller aliquots of an appropriate size for each anticipated use (and freeze-dried if desired). Repeated freeze-thaw cycles must be avoided to prevent damage and in any prolonged use, the integrity of the peptide should be regularly checked by HPLC. Dilute solutions of methionine containing peptides are prone to oxidation to the sulphoxide and should be used immediately after preparation. If you anticipate the need for regular use of smaller quantities of peptide, the peptide can be delivered already split down into the appropriate quantity. Please request when ordering.
Handling
Lyophilised peptides vary in physical form from easily handled dense powder to very light solids that are prone to influence from static electricity.
Since the toxicological properties of most peptides are unknown measures should always be taken to ensure that exposure to them is minimised. Standard laboratory procedures and personal protective equipment should be used to avoid skin and eye contact, ingestion and inhalation. Before weighing the peptide, allow the storage container to attain room temperature before opening. The peptide should not be exposed to the air for long periods since it may be hygroscopic.
Antibodies
Antibody reagents are normally most stable and best stored frozen at -20°C. We do recommend protecting your antibody by avoiding repeated freeze-thawing. In part, this can be achieved by dividing your sample into multiple aliquots on arrival for frozen storage.
Another aid is to store a working antibody aliquot in a refrigerator (rather than freezing it after use). Although immunoglobulins are relatively stable molecules we do add (unless otherwise instructed) 0.01% sodium azide as an antimicrobial agent and 1% trehalose as a stabiliser.
The trehalose is added to help maintain the three dimensional conformation of the antibody molecule and it will also protect the antibody if freeze-drying is required.
Note: Horseradish peroxidase will be inactivated in the presence of sodium azide but both sodium azide and trehalose can be removed by dialysis or buffer exchange chromatography of the antibody before coupling it to the enzyme.