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Overview
All GenScript peptides are delivered in lyophilized form and are protected by ArgonShieldTM packaging technology. Free peptide aliquoting is available upon request. To ensure stability of your peptides, store and handle them according to the guidelines below.
Storage Guidelines for Lyophilized Peptides
The stability of each peptide is unique and is dependent on its sequence. Lyophilized peptides should be stored at -20°C, away from bright light. Most lyophilized peptides are stable for several years under these conditions, however, certain amino acid residues in peptide sequences can thwart long-term stability. Peptides containing Cys, Met, or Trp residues are prone to oxidation and require storage under anaerobic conditions to maintain stability. Peptides containing Asp, Glu, Lys, Arg, or His are prone to moisture absorption from the air, called deliquescence. These peptides should be stored in a dessicator in a tightly capped vial.
In addition, peptides that undergo freeze-thaw cycles are susceptible to degradation. Whenever possible, the amount of peptide required for each experimental set should be pre-determined, and peptides should be aliquoted into separate vials accordingly. Aliquoting reduces the number of freeze-thaw cycles, and reduces the amount of air exposure to the peptide.
Storage Guidelines for Peptides in Solution
The shelf-life of peptides in solution is very limited, much shorter than that of lyophilized peptides. This is especially true for peptides whose sequences contain Cys, Met,Trp, Asp, Gln, and N-terminal Glu. In addition, peptides stored in solution are susceptible to bacterial degradation, therefore GenScript does not recommend storing peptides in solution. However, if storage of your peptide in solution is unavoidable, use buffers at pH5-6 to dissolve your peptide, divide the peptide solution into aliquots, and store the aliquots at -20°C. Avoid freeze-thaw cycles of the aliquots. You may choose to pass your peptide solution through a 0.2 μm filter to remove potential bacterial contamination from your peptide solution. If you dissolve too much of your peptide, re-lyophilization of the peptide solution will help you to maintain the stability of the excess peptide.
Preparing Peptides for Use
When preparing your peptides for use in an experiment or assay, follow the guidelines below:
1/
Warm the peptide vial to room temperature before opening.
2/
Weigh out the desired quantity of peptide quickly.
3/
Reseal the vial tightly.
4/
Store the remaining peptide in a freezer, preferably below -20°C, under dry conditions.
Peptide Stability Guidelines Quick Chart
For all peptides
DO avoid repeated freeze-thaw cycles DO aliquot lyophilized peptide according to daily experimental needs (Try GenScript’s free aliquoting service) DON’T store peptides long-term in solution DON’T repeatedly open the stock peptide vial For peptides containing Cys, Met, or Trp residues
DO limit peptide exposure to air DO purge assay buffers with argon or nitrogen gas DO store peptides in tightly capped vials For peptides containing Asp, Glu, Lys, Arg, or His
DO limit peptide exposure to air DO store lyophilized peptides in a dessicator DO store peptides in tightly capped vials For peptides that must be stored in solution
DO avoid repeated freeze-thaw cycles DO aliquot your peptide solution according to daily experimental needs DO use buffers to dissolve your peptide DO filter your peptide using a 0.2 μm filter to remove bacterial contamination
Delivery Specifications
All peptide synthesis is subject to GenScript's stringent quality control. The typical delivery consists of lyophilized peptide of the required sequence, purity, and quantity and associated QC reports.
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