ProteoGenix developed one of the most performing peptide synthesis platform on the market to provide the most competitive prices without compromising the quality and delivery time. Experience our online entertaining ordering form and have your peptide synthesis started immediately!
Why choose ProteoGenix' peptide synthesis services?
The most competitive price for peptide synthesis on the market.
Best price guaranteed
We guarantee to provide you the most competitive price.
Instant quotation and online order
Save time and buy your peptides directly thanks to our entertaining online form. Delivery in 10 business days.
Peptide synthesis up to 150 AA
As peptide synthesis experts, ProteoGenix can synthesize peptides up to 150 AA.
Unlimited range of modifications
ProteoGenix offers an unlimited range of peptide modifications to adapt to all your applications.
No win – no fee
Your project is our priority so we restart until we get the right peptide or you don’t pay.
Frequently asked questions about peptide synthesis
WHAT INCLUDES OUR PEPTIDE SYNTHESIS SERVICE ?
Our peptide synthesis service includes the lyophilized peptide and a report containing a complete QC analysis (amino acid sequence, modification information, peptide purity, mass spectrum, and HPLC).
WHICH PURITY GRADE SHOULD I CHOOSE FOR MY PEPTIDE SYNTHESIS ?
Peptide synthesis purity grade can have an important impact on the custom peptide synthesis price but can also be critical for the success of your experiments. For this reason, we put at your disposal a small table summarizing the peptide purity grade requested for several applications:
|Peptide purity grade||Applications|
Of course, if your application is not mentioned in the table, please feel free to contact our dedicated account manager who will be glad to help choose the most relevant peptide purity grade!
HOW CAN I SOLUBILIZE MY PEPTIDE?
ProteoGenix can deliver a solubility test service. In this case, you don’t need to consume part of your peptide stock for solubility testing.
If you choose to make it by yourself, the most commonly used method is based on charge determination of your peptide. For small peptides with up to 5 amino-acids, distilled water remains the first option. For other cases, you can refer to this small guide to help you define the optimal solubilizing conditions based on your custom peptide sequence:
Attribute -1 to each acidic residue (Asp / D, Glu / E) and to the terminal carboxylic acid. Assign +1 to each basic residues (Arg / R, Lys / K, His/h) and the terminal amine. Sum up both values to determine the overall charge of your peptide.
If the overall charge value is positive, try to dissolve your peptide in water. If the peptide does not dissolve, acidify your solution with an acetic acid solution (10 to 30%). Add TFA if acetic acid does not allow peptide dilution du sufficient concentration.
If the overall charge is negative and the peptide does not contain cysteine residues, try to dissolve your peptide in water. If the peptide does not dissolve, add ammonium hydroxide to obtain the desired concentration.
If the overall calculated charge is zero, dilution can be obtained with organic solvents such as methanol, ethanol, isopropanol or acetonitrile. A small amount of DMSO diluted with water can be used depending on final application. Specific care is requested for peptide containing cysteine, methionine or tryptophan residues as they are sensitive to oxidation. In these cases, replace DMSO by DMF.
Peptide synthesis for antibody production
Synthetic peptide antigens can represent powerful tools for polyclonal or monoclonal antibody generation (e.g. hybridoma development). Most of the time, peptide selection is based on native protein sequence examination for antigenic epitopes selection. Antigenic sequences are often chosen based on physico-chemical properties such as hydrophilicity, flexibility and accessibility as:
- Hydrophilic sequences are often privileged as proteins occurring in aqueous solutions have surface-exposed hydrophilic residues.
- Accessibility of the target sequence in the native protein must also be studied as the sterical hindrance can hamper antibody-antigen interaction.
- Secondary structure flexibility is also considered as a critical property as it makes it a good choice for antibody generation against native proteins.
The length of the peptide antigen is also a critical point to consider as short peptides (<10 AA) do not present a sufficient size to function as an epitope whereas long peptides (>20 AA) can adopt conformations that are not reflected in the native protein structure. Thus, a 10-20 AA peptide antigen is generally considered as an optimal for antibody production.
PEPTIDE COUPLING STRATEGY
A peptide alone generally tends to elicit only a weak immune response. To overcome this issue, it is usually conjugated to a carrier molecule. Peptide conjugation to a carrier necessitates considering mainly two points:
- Peptide orientation: a global rule is that the peptide should always be presented in a similar manner than it would be presented by the native protein.
- Nature of the carrier protein: carrier protein contains several epitopes stimulating the immune response. KLH and BSA are the most used carrier protein with a preference for KLH which is not involved in experimental assays and offers higher immunogenicity.
Peptide Synthesis Principle
Most peptide synthesis are based on Fmoc solid-phase synthesis developed by Atherton and Sheppard in the 1970’s.
Solid-phase peptide synthesis is based on stepwise amino-acid coupling leading to the desired peptide chain. In this method, the peptide chain is covalently attached to an insoluble resin, which consists in a synthetic polymer containing functional groups.
These groups react with the carboxylic end of N-protected amino-acids leading to a covalent coupling. Undesired reactions (and thus byproducts) are prevented by transient protection of terminal amino group and permanent protection of amino-acid side chains. Deprotection of the solid surface coupled amino-acid and activation of the carboxylic acid terminus of the added amino-acid leads to amino-acid coupling. Each step is separated by a washing step allowing eventual byproducts and reagents removal.
Peptide synthesis consists in a repetition of this reaction scheme until obtainment of the desired sequence. The final peptide is cleaved from the resin surface thanks to a strong acid (generally TFA).