1. How long has ADI been in business and what is the track record?
ADI has been making custom peptides and antibodies for about 15-years. We have made tens of thousands of custom peptide and antibodies. There is probably not a major research institution of a commercial company who has not worked with us at some time. Our researchers publish papers in most top-ranked journals such as Nature, PNAS, Science, JBC etc. ADI’s name can be found in al most every issue of top-ranked scientific journals. A list of these publications is posted at the web site.

2. What amount do I need peptide for antibody production? What should be length, amounts, purity, and should Cysteines be added?

Typically, 15-20 amino acid long peptides are sufficient for antibody production.  For some sequences, it may be necessary to use shorter peptide to reduce sequence homology or when antibodies are directed against the modified sequences (phosphopeptide or acetylated peptides).   A cysteine is typically added at the N-terminus (for C-terminal or internal peptides) or C-terminus (for N-terminal peptides).  If a cysteine is already part of the sequence then it will not be necessary to add the cysteine.

3.      What is the minimum length of the peptide for antibody production?

Typically, it is recommended to use 10-20 aa peptide for antibody production.  Shorter sequences will have less epitopes and reduced chances of antibody production.  We have made antibodies to 3-4 amino acid peptide.  It is simply more difficult to make such antibodies.  So the issue must be examined in light of actual peptide sequence.

4.      What purity should be enough for my application?

Peptides can be used for a variety of purposes.  So the minimum desired purity is dictated by the intended application.  Of course, one can always use the highest available purity for any application.  But it may not be necessary to have the highest purity (more cost) to achieve the scientific objectives.  Here are some common usage of peptides and suggested amounts and purities.

i) Antigen grade peptides (70-85% pure)

Peptides for antibody production- Typically antigen grade or immunological grade peptides (70-85% pure) are sufficient for this purpose.  10-15 mg total peptide is sufficient (~ 5 mg peptide is coupled to carrier protein such as KLH or BSA etc) and the rest is used for ELISA, antibody blocking and affinity purification of antibodies.

-For ELISA and antibody titer determination, and antibody blocking (need ~1 mg or less)

-For making affinity column for the purification of antibodies antibody (need 2-5 mg).

ii) Purified peptides (>90%)

-non quantitative enzyme-substrate studies
-phosphorylation reactions
-non-quantitative peptide blocking of antibodies, immunocytochemistry and in-vitro bio-assays
-coating of tissue culture plates for cell attachment
-protein electrophoresis applications

iii) >95% pure peptides

-standard for quantitative ELISA and RIA protocols
-quantitative receptor-ligand interaction studies
-in vitro bioassays, in vivo studies
-quantitative blocking and competition assays
-quantitative protease studies
-enzyme studies (in vitro kinase assay)
-chromatography standard
-NMR studies
-Monoclonal antibody production or antibodies to modified residues (phosphopeptides, acetylated).

5. Do I need acetylated or amidated peptides?

Most peptides for antibody production do not need acetylation or amide but they can be used. Manybiological peptides are acetylated and amidated -it increases stability and these modifications may even be necessary for biological activity. Whether to use acetylation and amidation is based upon the peptide functions.

6. How long a peptide can be synthesized?

In general, it is possible to make most peptides for up to 50-aa. Some small peptides are quite complex and difficult to make. We will review the sequence and let you know if we wish to undertake the synthesis of any given peptide. Although we have made peptide up to 100-aa but it becomes increasing difficult to make longer peptides with any reliability. Longer peptides are better suited for recombinant protein expression and purification.

7. How many phosphorylated residues can be introduced or made in a peptide?

It is quite feasible to make up to 2-3 phosphoresidues (tyrosine, serine, threonine) in a given peptide. However, the modified residues must be at least 3-4 amino acids apart.

8. How many cysteine-Cysteine bridges can be introduced?

We can perform up to two site-specific Cys-Cys oxidation (for example, Cys 5-10 & Cys 7-20). It will not be possible to make peptides with any reliability 3 or cys bridges. If a peptide contains 3 or more Cys-bridges then we can perform so called natural oxidation of the peptide (oxidize all cysteines assuming that they will pair with appropriate Cysteines). It will not be possible to determine the orientation of the Cysteines once the peptide has been oxidized.

9. Where can I add biotin or FITC on the peptides?

Biotin or FITC can be added on any amino at the N-terminus. You must have “K” or it can be added at the C-terminus to accommodate Biotin or FITC.

10. Can a degenerate peptide synthesis have more than 1 amino acid at the same position?

A sequence of 20-aa peptide, for example, may have just a few amino differences between human and mouse. In that case, it may be possible to add “K” and “R”, for example at position 15. We will add a mixture of “K and R” at position 15 so some peptide chains will have “K” and some will have “R”. This can be repeated at more than 1 position.

11. How do I select peptides for antibody production? Can ADI help me select the peptides from protein or DNA sequences?

ADI has an extensive experience in analyzing and selecting whole protein sequences to select short peptides of 15-20 amino acids that are antigenic and specific for the protein of interest. This service is offered free to our customers. Details are given “antigenic peptide selection”. There is an on-line form available to submit the sequence for analyses.

12. How can I find out how much is the price of the peptide? How can I obtain a quote from ADI? How can I place an order?

Typically you would send us the peptide sequence, all requested modification, purity, and amounts. We can send a price quote. There is an online form available to request the quote from ADI. Once the quote is obtained, the peptide order from can be sent to us by fax or processed on-line with a credit card payment.

13. What payment methods are acceptable?

Once you have ADI’s quote, the order can be placed on-line or by fax. You can provide either a purchase order number or charge to a credit card. All international orders must be paid at the time of order.

14. What is the typical turn around time for custom peptide orders?

Most peptides will be completed within 2-4 weeks. Some peptide may be complex or will not pass our quality control. A tentative schedule will be provided when the order is placed. If any delay is anticipated, you will be kept informed. Any peptide does not pass the Q.C., will be re-synthesize at our expense. In case of complete failure, we must abandon the order. There will be no charge assessed on failed peptides.

15. How are peptides shipped? what is the shipping charge in the USA and International?

All peptide are shipped in powder form at room temp delivered overnight by Federal Express or DHL. Typically, US charges are $30 per shipment ($60-70 or more for intl. Orders). If you have multiple peptides, then we will wait to complete the orders. If there is unusual delay, then you will be contacted to determine if partial shipment is OK.

16. Do I need to have the peptides coupled to KLH or BSA or Agarose?

We can coupled a portion of the peptide to KLH or BSA or other carrier proteins or prepare an affinity column. Please see details of the procedure and charges.

17. How should I store and dissolve the peptides?

All peptides are shipped at room temperature. They are best stored in a dry container at –20oC or below. There are detailed instructions available on dissolving the peptides. Please note that we do not have to dissolve the peptides in aqueous buffer for peptide synthesis or QC. Therefore, we will have no experience in dissolving a given peptide. If we have made the peptide-Protein conjugate or done something with it then this information will be provided on the peptide data sheets.

18. How long are the peptides stable?

Peptide stability is dictated by the sequence. Some amino acids are more stable than others. We will have no experience with the custom peptides. Most peptides can be stored under dry and frozen conditions for several months. While a peptide may lose its biological function but retain its antibody recognitions. Therefore, peptide stability must be evaluated for its ultimate use.

19. What is the typical purity of crude peptides? How are peptides purified? How is purity verified?

Most peptides are 40-60% pure at the crude stage. Purity is determined by HPLC . All peptides are purified by reverse phase HPLC until the desired purity is achieved. Mass specs are performed to confirm the molecular weights.

20.   What are the impurities in the peptides?

Peptides are made using purified chemicals and solvents.  So all impurities are derived from these sources.  A peptide may contain the following.
-          Deletion sequences, Truncation sequences, Incompletely deprotected sequences
-          Sequences modified during cleavage (reattachment of protecting groups at other locations on the peptide)
-          DTT (dithiothreitol), TFA (trifluoroacetic acid), Acetic acid
-          Peptides that have undergone side reactions such as proline isomerization or isoaspartimide formation, etc
Purified peptides will have most the truncated and other sequence removed and mass verified by mass spec.

21. What does purity means and what is the peptide content?

Due to the presence of variable amounts of TFA and other traces of chemicals, peptide content will be less than the stated amounts on the vials. Typically, there may be 10-20% of non-peptide material present. For some analyses, it may be necessary to determine the ‘peptide content’ by amino acid analyses. There is a separate charge for this services and it is not typically required or performed. The peptides are sent on physical dry weight.

22. What are the Endotoxin content in the peptide?

We use highly purified chemicals and solvents for synthesis that are typically free from Endotoxin. However, we do not determine Endotoxin content after peptide synthesis.

23. What happens when peptide cannot be made or only partial amounts are shipped?

Our policy is to complete all orders to your specification. If it is possible to ship only a partial amount, you will be given the option of accepting a partial amount; if you accept, you would be billed for the amount shipped. All failed peptides will have a re-synthesis done at our expense. In rare cases, we may not be able to make the peptide after repeated attempts. There will be no charge assessed on failed peptides.

24. What does the purity means? Why does mass spec show more than 1 peak and higher than the expected size?

Purity of all peptides is determined by HPLC. We will meet the purity requirements and HPLC data sent with the peptide. Mass spec is performed to confirm the size of the peptides. Often, a peptide may show more than 1 peak due to metal or water molecules. Such peaks will be annotated in the supplied mass spectrum.

25. How do I calculate the from pg/tube to pmol/l?

Molecular weight of the peptide will be provided in the data sheet. In short form:

Please contact us by email or by phone if you don’t find your answer.