Peptide Synthesis FAQs

Q1) How to store and handle peptides?
Ans: All peptides are delivered lyophilized.

Storage Guidelines for Lyophilized Peptides: 
Peptides that are delivered should be kept in the fridge and away from light. To store for a short duration, a few days to 2 months, the lyophilised peptides may be stored at 4 degree Celsius. For longer period, they should be stored at -20 degree Celsius. This will keep peptides stable for years; however exposure to moisture might affect the peptides' stability. So, it is best that peptides vials are kept tightly closed with minimal opening.

Peptide Solutions Storage Guideline:
Peptides that have been reconstituted have a limited shelf life. Cysteine, Methionine, Tryptophan, Asparagine, Glutamine and N-Glutamic Acid are some examples of these peptides. Do take the amount that is required and keep the remaining lyophilised. Note also that reconstited peptides are prone to bacterial attack. If storing in solution form is unavoidable, do use a sterile buffer at pH 5 and store aliquots at -20 degree Celsius. Prior to application, pass this through a 0.2um filter to eliminate the bacteria

Preparation for Use: 
Step 1: At room temperature, open the vial and quickly weigh the amount required. (If peptides are not at room temperature, do let it stand for about half to an hour prior to opening vial)

Step 2: Reseal the vial and store under -20 degree Celsius, devoid of moisture

Avoid freeze-thaw, best that peptides are aliquoted into a series if frequent sample taking is required. Peptides with Cysteine, Methionine and Tryptophan are prone to oxidation. Hence, to store these peptides, air need to be removed and replaced with inert gas such as Argon.

 

Q2) What should I consider while designing my custom peptide?
Ans:

  • Solubility - It is important to consider if the peptide will be soluble enough for your application and/or soluble in HPLC compatible solvents to allow for its purification to the desired degree of purity. Generally, peptides composed of predominantly hydrophobic amino acids (W, Y, F, L, I, V, M, C, A) tend to be less soluble in aqueous solvents. Hydrophilic amino acids such as R, K, H, S, T, D, or E help in peptide solubility, dependent on their prevalence in the sequence.
  • Potential synthesis difficulties - While most peptides can be synthesized and purified successfully, sometimes minor modifications to the sequence may greatly improve the chance of a successful synthesis and could shorten the manufacturing or purification process or even lower its cost. To minimize synthesis difficulties, please email us your sequences so that we can run a quick analysis to identify likely synthesis difficulties and suggest alternatives.
  • Labeling of peptides - Attachment of various labels (biotin, fluorescein, etc.) to the peptide is most straightforward when these labels are to be attached at the N-terminus. Attachment at the C-terminus or in the middle of the sequence is more demanding and more expensive.


Q3) What is the required purity of the peptides for my application?
Ans:

70% 80% 90% 95% 97-98%
Immunograde purity, antibody production
  Non-sensitive screening assays
  Enzymology, bioactivity studies
  Bioassays receptor-ligand studies, structural studies

 

Q4) What is the IUPAC amino acid code?
Ans:

Alanine Ala A Methionine Met M
Cystein Cys C Asparagine Asn N
Aspartic Acid Asp D Proline Pro P
Glutamic Acid Glu E Glutamine Gln Q
Phenylalanine Phe F Arginine Arg R
Glycine Gly G Serine Ser S
Histidine His H Threonine Thr T
Isoleucine Ile I Valine Val V
Lysine Lys K Tryptophan Trp W
Leucine Leu L Tyrosine Tyr Y

 

Q5) What quality control assurances are there on our synthetic peptides?
Ans: All peptides synthesized are provided with a complete quality control package, which includes HPLC chromatograms to ensure purity and mass spectral analysis to confirm identity.