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General Information
1. How do I place my order?
Creative Peptides offers 3 ways to order your products:
1) Email us at info@creative-peptides.com
2) Call us at 1-631-624-4882
3) Download an order form and fax it to us at 1-631-614-7828
2. What kinds of payment do you accept?
Creative Peptides accepts credit cards (Visa, MasterCard, American Express), checks, and wire transfers. For orders, you may send us a PO (Purchase Order). Creative Peptides may require a deposit for certain orders.
3. How do you ship peptides? What data will be provided?
All peptides are lyophilized and shipped in 2 mL microcentrifuge tubes or penicillin bottles. Large amounts of peptides may be aliquoted into several tubes upon request. For each peptide, QC reports containing the amino acid sequence, modification information, peptide purity, mass spectrum, and HPLC chromatogram will be provided.
4. What is the typical turnaround time for peptide synthesis at Creative Peptides?
Typical turnaround time is about 3-4 weeks. The turnaround time may vary depending on the peptide length and complexity.
Peptide Storage and Solubility
1. What is the best way to dissolve my peptide?
Different peptides will have different solubilities, based on the content of the peptides. As a general rule, peptides should first be dissolved in distilled, preferably sterile water, If solubility still remains a problem, try the following steps:
---Dissolve peptides in an appropriate buffer: acidic peptides or proteins in basic buffer and basic peptides in acidic buffer. If necessary, the solution can be sonicated briefly.
---It is also recommended that the peptide be dissolved to the highest possible concentration, and then diluted with water or buffer to the working concentration.
---Peptides containing Trp, Met or Cys require special care to avoid oxidation. Oxygen-free water or reducing agents can be used.
2. How should I store my peptides?
Peptides are delivered in lyophilized form and often hydroscopic. Absorption of water will decrease stability of the peptide and may reduce overall peptide content.
For best results, please note: 
---Maintain a dry environment and use a desicator. 
---For storage, peptide should be kept frozen at -20℃ for maximum stability. 
---Most peptides containing Trp, Met, Cys, Asn or Gln have limited lifetime. Long-term storage is not recommended.
3. How do I handle my peptides? What do I do if my peptide refuses to dissolve?
Just dilute the peptide to the concentration which is suggested on the Certificate of Analysis provided by us. You should use distilled, sterile water for dilution. Concentrations between 1-10mg/ml are recommended. At first please follow the special instructions (addition of a special solvent) we mention for certain peptides on the Certificate of Analysis. The solubility of a peptide always depends on its amino acid composition, and can be difficult, particularly if the peptides are very hydrophobic. 
The first solvent of choice is deionised water. Sonication may help to dissolve the peptide. We recommend solubilising a small quantity of peptide to determine optimal solubilisation conditions.
Peptide Purity
1. What means "purity" and why do peptides have to be purified?
A purity of 95% means for example that 95% of the sample contains full length peptides. The other 5% are truncated synthesis fragments. Residual toxic reagents have to be removed. Coupling is never 100% efficient. During synthesis truncated and deletion sequences accumulate which might interfere with the activity of the peptide.
2. Which purity degree do I need for my peptide?
This depends on the application. For immunological applications (raising antibodies), 70% purity is excellent. For peptide library binding screening, crude or 70% purity is also fine.
For cell biological studies, such as cellular activation or drug screening in cell culture, 95% purity is essential.
For structural studies (NMR, X-ray, Mass Spectrometry) or receptor / ligand studies, 95% purity is advisable.
3. What is net peptide content and peptide purity? What the difference between them?
The weight of lyophilized peptide powder does not consist of peptide only, but includes non-peptide components such as water, absorbed solvents, counter ions and salts. Net peptide content is the actual percent weight of peptide. This percent may vary, from 50 to 90, depending on the purity, sequence and method of synthesis and purification. Do not confuse peptide content with purity; they are two distinctly separate things. Purity is determined using HPLC, and revealed the presence or absence of contaminating peptides with the incorrect sequences. In contrast, the net peptide content only gives information on the percent of peptide versus non-peptide components. Net peptide content is accurately found by performing amino acid analysis or UV spectrophotometry. This information is important when calculating concentrations of peptide during sensitive experiments.
4. What is the purity for crude level peptide?
The purity for crude peptides from Creative Peptides is in the range of 50-60%.
5. What salt form should I use and how to remove TFA?
The custom synthesis peptides from Creative Peptides are all TFA free. Peptides are usually delivered as TFA salts. If residual TFA would be problematic for your experiment (cell experiment), we recommend other salt forms such as acetate and hydrochloride. These salt forms are usually 10-20% more expensive than the regular TFA salt because of the peptide loss that takes place during the salt conversion and the greater amounts of raw materials required. It is important that purified peptides be free of Trifluoroacetate (TFA) salts because TFA could alter the results of downstream biological assays.
Peptide Synthesis
1. What methods do you use to synthesize peptides?
For peptides fewer than 50 amino acids in length, we use stepwise SPPS chemical methods. For peptides more than 50 amino acids in length, we use fragment condensation and native ligation methods.
2. What if there is a problem with the synthesis of my peptide?
Each peptide has specific characteristics and the outcome of a synthesis attempt cannot always be anticipated. If for some reason we cannot deliver your peptide on time, we will inform you as soon as possible. However, Creative Peptides has a 95% synthesis success rate for custom peptides and can deliver even the most complex peptides.
3. What is the maximum peptide length Creative Peptides can synthesize?
Creative Peptides can synthesize peptides of length up to 200 AA. Peptides of 50-70 AA can be obtained by direct chemical synthesis. Longer peptides can be generated by chemically linking several synthetic peptide components. Proteins can also be chemically synthesized.
4. What is your purification process and QC?
All peptides are analyzed by Mass Spectrometry to determine the molecular weight of the synthesized peptide, free of charge. Comparison of the theoretical molecular weight with the experimentally determined molecular weight confirms the absence of amino acid deletions or double couplings. MS is an excellent method for determining the presence of the desired product, but an inadequate method for the determination of purity. Due to the variant efficiencies of peptide ionization in the MS instrument, peak intensities in MS spectra are not necessarily quantitative. For this reason all non-crude peptides at Creative Peptides are analysed by Reverse-Phase HPLC (RP-HPLC) to determine purity. Precipitated peptides are analysed on a Waters Alliance, RP-HPLC instrument equipped with an auto-sampler for continuous analysis. Peptides that meet or exceed the purity requirements are then lyophilized, packaged and shipped to the customer at room temperature by overnight dispatch. Peptides are available as crude, esalted, >70%, >75%, >80%, >85%, >90%, >95% and > 98 % purity depending on your research applications.
5. What are peptide libraries and how can I use them?
A Peptide library is the systematic combination of different peptides in large numbers. It has proven to be a powerful tool for drug discovery, structural studies and other applications.
Some common applications of a peptide library are as follows: description of variations of antibody specificity (epitopes), identification of bioactive peptides and ligand-binding activities, the generation of synthetic vaccines and antimicrobial peptides, as well as purification of peptides.
One of the advantages of peptide libraries prepared by solid phase synthesis is that the peptides can remain on a solid support. Detection of specific peptides can be done via standard immunological enzyme staining methods, and are then manually separable under microscopy to determine the peptide sequences directly. For libraries, we are able to offer the following: Keep the peptide on/off the resin, scramble the amino acids, use specific linkers, dye-label, as well as many other modifications.
6. What are peptide arrays and how can I use them?
Peptide Arrays are the production of a large number of peptide sequences (minimum 96 peptides) for use in high throughput screening. We can produce peptides of up to 18 amino acids in length at a 2.5 μmol, 5 μmol, and 10 μmol scale. Arrays can be used for epitope mapping, peptide libraries, protein characterization and much more.
7. Can you provide cGMP-grade peptides?
Creative Peptides provides large-scale cGMP-grade peptide services with capacity up to 2 kilograms per project. Our comprehensive experiences in cGMP-grade peptide synthesis for therapeutic and diagnostic applications give us an edge over the competition. We guarantee consistency, viability, and delivery.
8. What are the Cell-Penetrating Peptides?
Cell-penetrating peptides (CPPs), also known as protein transduction domains (PTDs) or membrane transduction peptides (MTPs) have been widely used for the intracellular uptake and delivery of various macromolecules, or "cargo", which are associated with the peptides either via covalent bond or through non-covalent interaction, such as TAT family peptides. As an attractive pharmaceutical and biochemical tool, CPPs can overcome the impermeable nature of cell membrane to facilitate the cellular penetration of potential drugs into mammalian cells. Applications of cell-penetrating peptides for delivering various macromolecules with biological functions into cells begin to come into vogue.
Creative Peptides is an international supplier of innovative peptide synthsis services for the academic and industrial community. With our state-of-the-art equipment and experienced chemists, we are committed to a comprehensive series of Cell-penetrating Peptides Synthesis Services and Total Quality Management (TQM) to fulfill customers' complete satisfaction.
9. Which modifications do you offer?
C-terminal amidation, N-terminal acetylation, biotinylation, fluorescent labels, phosphorylation, glycosylation, Isotope label, cyclization, incorporation of D amino acids and many more. If you have any uncommon modified peptides, including report in a scientific article, synthesis requirement in mind, feel free to let us know. It is very likely that we are capable of producing them. We would be highly appreciate if you could provide us with a copy of the article or give us an online reference, so that we can look into the production method used and assess whether we can successfully synthesize the peptides for you. We will inform you about our assessment within 72 hours.
10. What would be the appropriate modification choice for my peptide terminals?
For internal protein sequence peptides, we suggest applying terminal amidation (C-terminus) or acetylation (N-terminus) in order to remove terminal charges and further imitate its natural structure (amide, CONH2). This modification secures the stability of the peptide from potential enzymatic degradation, such as exopeptidase.
11. Can you aliquot my peptides?
According to request, Creative Peptides can aliquot part or all of your order into smaller quantities. Aliquoted products are more expensive but may save you time, effort and money during determination of peptide solubility. Your peptides will also be more stable because they will not be exposed to as many freeze-thaw cycles, as many openings and closings of the container, mishandling, or bacterial contamination. Peptide oxidation, degradation, and aggregation are less prevalent in aliquoted samples.
Frequently Asked Questions: SPRi service
1. What is the SPRi?
Answer: SPRi (Surface plasmon resonance imaging) is a real-time, label-free, and high-throughput technique which is widely used to study biomolecular interactions. It can be used to examine affinity between biomoleculars, screen biomarkers and detect biopsy specimens.
2. What kind of information can be obtained using the SPRi technique?
SPRi can monitor the biomolecular interactions in a real-time manner, including kinetic processes, binding affinity and binding specificity.
3. What kind of interactions can be studied?
A vast library of samples can be analyzed, including proteins, peptides, nucleic-acids, carbohydrates, bacteria, cells, polymers and so on.
4. What kind of molecules can be immobilized on a SPRi-biochip?
Various soluble molecules can be immobilized on the appropriate SPRi-biochip surface, such as antibodies, proteins, saccharides, DNA, RNA and so on.
5. How SPRi is used to monitor molecular interactions?
SPRi is used to monitor changes of the refractive index occurring at the surface of the SPRi-biochip. When a binding event (or mass accumulation) occurs, it will induce a change of refractive index and a shift of the position of the resonance angle.
6. What forms of sample do you accept?
Any form of samples can be acceptable. Both purified moleculars (such as protein, peptide, DNA etc) and crude samples (such as serum, CSF, cell lysates etc) are OK.
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