Storage of Lyophilised Peptides
All products should be stored and refrigerated, preferably at -20^OC. Most peptides stored in this way will remain stable for several years.

Storage of Peptides in Solution
Peptides in solution are much less stable than in the lyophilised form. Solutions should be made up at neutral pH (pH 5-7) and stored frozen at -20^OC. To avoid repeated thawing and refreezing of the sample it is recommended that the peptide stock solution be divided into aliquots. Any portion of an aliquot unused after thawing should be discarded. Bacterial degradation can occasionally be a problem with peptides in solution. To overcome this, peptides can either be dissolved in sterile water solutions or else the peptide solution can be passed through a 0.2µM filter.

Reconstitution and Handling of Peptides
Most peptides will be soluble in sterile distilled water. When first solubilising the peptide care should be taken to ensure that the initial concentration is greater than the desired final concentration. This will allow for the addition of other solubilising agents should the peptide prove to have only limited solubility or buffer salts.

If the peptide exhibits only limited solubility in water, then several options are open to aid this process. Addition of:-
1) Dilute acetic acid (0.1M) for basic peptides. (Containing Arg, Lys, His)
2) Dilute ammonia (0.1M) for acidic peptides. (Containing Asp, Glu)
3) 10% organic modifier (ie. Acetonitrile, Methanol) for very hydrophobic peptides.
4) DMSO or DMF for extremely insoluble peptides.
5) Concentrated solutions of either guanidine hydrochloride or urea may also be useful.
In conjunction with the options outlined above, sonication can also be a useful aid for
solubilising peptides.
(NOTE: The use of organics such as Methanol, Acetonitrile, DMSO etc. may interfere with some biological assays.)

Contact us for further information or with specific questions.