FAQ: Custom Peptide Synthesis

Please refer to the corresponding frequently asked questions (FAQs) below.
If you can not find the question you are looking for, please contact our customer support team:

How does JPT Peptide Technologies QC its products?

With exception of our crude peptides, which will only be checked for identity by MALDI-MS, all synthetic peptides will be analyzed by HPLC and MS.
Beside MALDI-MS our routine application involves HPLC-MS techniques to guarantee that a peak visible in the HPLC profile corresponds to the target mass.
Since peptides show different ion response depending on the actual primary sequence, availability of different MS-equipment is crucial for doubtless analysis.
At JPT Peptide Technologies’ state of the art equipment (MALDI-MS, HPLC-(ESI)MS (ion trap and quadrupole) guarantees unambiguous analysis.
In addition, JPT Peptide Technologies offers optional amino acid analysis and peptide content determination.
Analytical Data Sheets and analytical data are delivered with each peptide.

Is there any limitation on the length of peptides that can be achieved?

JPT Peptide Technologies offers custom service for peptides ranging from 2 to appr. 100 amino acids.
Standard stepwise solid phase procedures provide access to most of the peptides in range from 5 to 50 amino acids in length.
For short peptides (i.e. dimers, trimers etc.) and peptides with special modification we have solution phase approaches available.
For long peptides up to appr. 100 amino acids we use our proprietary convergent peptide synthesis approach.
For longer peptides the success rate drops below 50% and therefore recombinant technologies might be advantageous.

What purity levels are available and which purity is needed for my application?

JPT Peptide Technologies offers different purity levels starting with >70% up to >95%.
Ultra pure materials with >97% purity are available upon request.
The following list might serve as guideline for peptide specification:
>70%: immunological applications, epitope discovery, and nonsensitive screening;
>80%: immunological applications and epitope validation;
>90%: SAR studies, immune monitoring assays;
>95%: NMR, crystallization, enzymatic assays;
>97%: NMR, crystallization, sensitive bioassays.

At what scale are peptides synthesized?

JPT Peptide Technologies synthesizes custom peptides in a range from mg (smaller aliquots available) up to several grams per peptide.

How do I dissolve my peptides?

Solubility of peptides greatly depends on various parameters like primary and secondary structure, nature of modifications made, solvent, pH value and final concentration.
Therefore, solubility is hardly to predict.
If a peptide is difficult to solubilize in aqueous solution, sonification will support solubility.
For basic peptides, 10% acetic acid has been recommended whereas for acidic peptides, aqueous ammonia or 10% ammonium bicarbonate solution were shown to be helpful.
For peptides having poor solubility in aqueous solutions, organic solvents have to be applied.
Use the minimal amount of organic solvent (DMSO is preferred but DMF, DMA, isopropanol, methanol and others can also be used) to dissolve your peptide.
We strongly recommend to dissolve the peptide first in the organic solvent.
In a second step, water or other aqueous media should be added in stepwise manner until the final concentration is reached.

How do I solubilize peptides that don't go into solution using aqeous buffers?

We do suggest the following:

a) Start with pure DMSO to dissolve the peptides
b) Apply a small volume first and use vortexing and/or sonication
c) Apply more DMSO and vortex/sonicate again if peptides don't go in solution
d) You may consider higher temp. 40-50°C if points a-c don't work
e) Once the peptides are dissolved in pure DMSO start dilution with buffer
f)  Important: use small volumes to dilute DMSO in a stepwise manner. Always add the buffer to the DMSO   
g) Use sonication/vortexing after each addition of buffer
h) Watch out for a cloudy solution. This is a sign for of precipitation. Use sonication again to get rid of minor precipitation

Does JPT Peptide Technologies provide the modifications I need?

JPT Peptide Technologies provides a large variety of well established peptide modifications like acetylation, biotinylation, phosphorylation and attachment of fluorescent dyes or quencher pairs but is also specialized in doing unusal reactions.
It will be a pleasure to discuss your special needs in detail.

What kinds of peptide endings are most appropriate for my studies?

The default ends of a peptide are a free amine group at the N-terminus and an acid group at the C-terminus.
However, a peptide often represents a part of a parental protein sequence.
In that case, the more “native” ends would relate to blocked N-terminus (i.e. acetyl) and C-terminus (i.e.amide).
In addition, this modification avoids the introduction of additional charges and stabilizes the resulting peptide towards enzymatic degradation resulting from exopeptidases.

How many peptides can JPT Peptide Technologies synthesize?

JPT Peptide Technologies is known for its patented high throughput technologies.
Up to one hundred thousand isolated peptides can be produced in weeks.

What kinds of synthesis methods are available?

JPT Peptide Technologies possesses a complete range of peptide synthesis techniques including: solid phase synthesis and solution phase synthesis techniques BOC chemistry and Fmoc chemistry stepwise synthesis, convergent synthesis approaches, ligation techniques, nano scale peptide synthesis to multigram scale manual peptide synthesis and automated proprietary high throughput peptide synthesis.

What is net weight and peptide content?

Peptides are normally delivered as fluffy lyophilized material.
Due to the nature of the peptides, they may still contain traces of moisture and counter ions on protonated amino functions (N-terminus, Arg, His, Lys, etc.).
This is not considered an impurity, but reduces the actual peptide content by approximately 10 to 30%.
The net peptide weight is the actual weight of the peptide minus the additional weight from residual moisture and counter ions.
In order to ensure an accurate peptide concentration, the non-peptide weigth needs to be considered and substracted from the gross peptide weight.
An accurate determination of the peptide net weight can be performed by quantitative amino acid analysis, which is also available upon request.

How long does it take from order to delivery?

Routinely, assembly and purification and quality control of medium size peptides takes 3-4 weeks.
In addition, JPT Peptide Technologies offers rush order options guaranteeing extremely short delivery times upon request.

How does JPT Peptide Technologies ship the peptides? Which data will be provided?

All peptides will be shipped lyophilized in small polypropylene vials (2 ml or 10ml) with screw caps.
Alternatively, smaller aliquots will be shipped in small amber type glass tubes (1.8ml) with screw caps.
All tubes contain labels with information on primary sequence, amount and batch number.
The peptides provided will be accompanied by the original analytical data achieved and an analytical data sheet providing comprehensive information about key characteristics of the peptide such as primary sequence, molecular mass, morphology, counter-ions, purity, etc.

What are the best storage conditions and how stable are the peptides?

Generally, most peptides are stable over years when stored at -20°C in freeze dried state.
However, peptides containing amino acids such as Met, Cys or N-terminal Gln tend to oxidation or pyroglutamate formation.
Since kinetics of such deterioration depends on primary peptide structure, stability can hardly be predicted.
Therefore, we recommend usage of peptides within 6 months.
Recommended storage conditions are: -20°C or colder in a dry environment.
Avoid repeated freeze-thaw cycles. Avoid long-term storage of aliquots in solution.
If solubilized (ex. in DMSO) aliquots can’t be avoided, store at -80°C.

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