Lyophilized Peptides Storage Guidelines:
Lyophilized peptides should be refrigerated and stored away from bright light. For short-term storage ranging from one week to two months, lyophilized peptides may be stored at 4 degree. For long-term storage, lyophilized peptide should be stored at -20 degree in deep freezer. Even though this condition keeps most peptides stable for several years, peptides long term stability is at risk when peptides expose to moisture. Therefore, the vial should be tightly capped at all times. This also requires careful experiment planning to minimize vial openings.
Peptide Solutions Storage Guideline:
Do not store excessive peptides in solution because the shelf life of peptides in solution is very limited, much shorter than lyophilized peptides. This is especially true for peptides whose sequences contain cysteine, methionine, tryptophan, asparagine, glutamine or N-terminal glutamic acid. It is necessary to aliquot the amount of peptide you need for the day and re-lyophilize the remaining peptide solution. Another drawback is that peptides stored in solution are susceptible to bacterial degradation. If storage of peptide in solution is unavoidable, use sterile buffers at pH 5-6 and store aliquots at -20 degree; and pass the peptide solution through a 0.2 µM filter to rid the bacteria. The peptide powder can be store at room temperature for 1 week. If the sequence contains M, W or C, it can not be stored at room temp.