Custom Peptide Synthesis FAQs
General Peptide Questions
- What type of chemistry do CanPeptide use?
- What’s the turn-around time for my peptides?
- What levels of purity are available and what purity is appropriate for my application?
- What purity can be expected from the non-purified and desalted peptides?
- How do you generally purify the peptides?
- How are my peptides shipped and what’s the cost?
- What data will be provided along with the product shipping?
- Can you explain the [M+Na] and [M+K] peaks observed in the MALDI-TOF or ESI mass spectra?
- What does CanPeptide do if some problems happen during making my peptides?
- How should I store my peptides? How can I dissolve my peptide when it shows poor solubility?
Peptide Modification Questions
- Do my peptides need N-terminal acetylation and C-terminal amidation?
- Is there any charge for N-terminus acetylation and C-terminus amidation?
- Does CanPeptide provide resin-associated peptides?
- How can I know if the biotin is on N-terminal, not somewhere else?
- When do the N-term biotinylation, will a spacer be inserted between biotin and peptide chain?
- Should I add a spacer between my peptide and a dye modification?
- Does CanPeptide synthesize cyclic peptides?
- Does CanPeptide do peptide PEGylation? What are the advantages?
1. What synthesis methodologies do CanPeptide use?
We use optimized Fmoc chemistry, both solid phase and solution phase methodologies for the peptide production. Automated or manual peptide synthesis is performed where appropriate.
2. What’s the turn-around time for my peptides?
Generally, the turn-around time for the crude products is 1-2 weeks and 2-3 weeks for the purified lyophilizates. It may vary depending on the peptide length and difficulty.
3. What levels of purity are available and what purity is appropriate for my application?CanPeptide offers different purity levels of peptides ranging from 70%-95%, or even higher, e.g., >98%, upon request.
Peptides with >70% purity are recommended for screening purposes and polyclonal antibody production. Peptides with >80% purity are also used for antibody production and immunological applications. For ligand binding studies, enzymology, in-vitro bioassay and biological activity studies, we tend to recommend using peptides with a purity of 90% or higher to insure reliability and good experimental reproducibility. For in-vivo studies and structural studies (e.g., NMR and Crystallography), a higher purity of 98% is recommended.
4. What purity can be expected from the non-purified and desalted peptides?
Generally >60%. However, depending on the difficulty of the sequences, this estimation cannot be guaranteed for all cases.
5. How do you generally purifythe peptides?
We use RP-HPLC to purify the peptides to the expected purity.
6. How are my peptides shipped and what’s the cost?
Peptides are shipped via FedEx. Currently, the shipping is at no charge.
7. What data will be provided along with the product shipping?
HPLC chromatogram, Mass Spectra and Certificate of Analysis containing the features of the product, such as primary amino acid sequence, modification, quantity packed and purity, etc.
8. Can you explain the [M+Na] and [M+K] mass peaks observed in the MALDI-TOF or ESI mass spectra?
Peptide molecules can be ionized by the Na+ or/and K+, it is common to see their adducts from the MALDI-TOF or ESI mass spectra. Those ions come from the water used for the peptide purification or the buffer used for the mass analysis. They can never be completely removed, even distilled or deionized water is used. Instead of ionized by proton, some peptide molecules are ionized by Na+ or/and K+. It is common and normal to observe the [M+Na] and [M+K] peaks in MALDI-TOF mass spec.
9. What does CanPeptide do if some problems happen during making my peptides?
If due to the synthesis difficulty, the product cannot be delivered on time, we will inform you as soon as possible. However, every endeavor will be made to secure the product quality and the delivery time.
10. How should I store my peptides? How can I dissolve my peptide when it shows poor solubility?
Please take a look at our Storage & Handling guideline or consult our scientist for more information
Peptide Modification Questions
1. Do my peptides need N-terminal acetylation and C-terminal amidation?
These modifications may avoid unnatural charges at the peptide terminals and protect the peptides from degradation resulting from exopeptidases. We suggest having the C-terminal amidation, which make the peptide more closely mimic the charge state in the native protein.
2. Is there any charge for N-terminus acetylation and C-terminus amidation?
No, there is no extra charge for these services.
3. Does Canpeptide provide resin-associated peptides?
We can provide you with the peptides attached to the resins through C-terminus, which can be used for library screening. Depending on the applications, peptides can be attached to PS and PEG-based resins, etc.
4. How can I know if the biotin is on N-terminal, not somewhere else?
All other reactive groups are blocked throughout the synthesis and only the free N-terminal is available for biotinylation.
5. When doing the N-term biotinylation, will a spacer be inserted between biotin and peptide chain?
By our standard process, a 6-carbon spacer, aminohexanoyl (ε-ahx), will be inserted between biotin and peptide chain.
6. Should I add a spacer between the peptide chain and a dye label?
When attach a dye label onto the peptide, it is suggested to insert a spacer between the peptide chain and the ligand. This will minimize the interference in the folding of the peptide and/or its binding to the receptor. However, in some cases the spacer is not needed or should not be added. For example, when studying protein folding, the fluorescent dyes are attached to specific amino acids at specific positions to study how far or close they are in the folded structure, by quantifying fluorescence transfer. Generally, for protein/peptide binding or targeting studies, a spacer is recommended. For purely structural studies, a spacer is not required and can often hinder the response.
7. Does CanPeptide synthesize cyclic peptides?
Yes, we are experienced in making various cyclic peptides such as Disulfide Bridge, thioether and peptide macrolactams, etc.
8. Does CanPeptide do peptide PEGylation? What are the advantages?
Yes, we can do the peptide PEGylation. Among the advantages of PEGylation technology are increased peptide solubility, increased bioavailability, increased in-vivo stability, optimized pharmacokinetics, decreased immunogenicity, etc.