Can you tell me how do you generally purify your peptides so that I know what kind of impurities we are expecting?
The impurities are most likely water and salts, TFA, solvents, truncation or deprotected sequences, etc.
Can you perform KLH or BSA conjugation without cys in sequence?
Yes, but we could not control where the KLH/BSA will be conjugaed. The efficiency will be lower as well. We recommand adding an Cys to the sequence for conjugation.
Can you synthesize peptides with all D-amino acid? what is the estimated turnaround time and cost?
Yes, we can. The turnaround time is around 2 to 3 weeks. The cost will be higher than L-amino acid and there would be extra $30/D-amino acid compared to regular amino acid.
Can you let me know the percentage of purity of "Crude"?
We cannot guarantee crude peptide purity level. The HPLC will indicate the actual purity and the crude level can vary in a wide range.
How do you ship peptides?
All peptides will be lyophilized and shipped in small microcentrifuge tubes at room temperature. Based on our customers' requirement, large amounts of peptide can be aliquoted into several tubes. For each peptide, data sheets containing information such as amino acid sequence, purity, mass spectrum, HPLC data and modifications will be provided.
How should clients store peptides?
Lyophilized peptides can be stored in a dry and tightly closed vessel at -20°C, be provented from intense sunlight.
Lyophilized peptides may be stored at 4°C for short-term storage ranging from 1 week to 2 months.
Lyophilized peptides can be stored at -20°C or freezer for long-termstorage.
A peptide solution once prepared should be used as soon as possible.
What is our quality control standard?
Alan Scientific will send the product to customer with LC-MS, HPLC and COA reports to guarantee the quality of our peptides.
What is the Fmoc strategy in SPPS?
SPPS is the peptide synthesize based on the solid support which is also known as resin, linkers are modified on the resin to provide the reactive group for the first amino acid. Peptide is synthesized through the amide bond between the amide group and carboxyl group from another in the condition of pre-activated species or in situ activation. To avoid the undesired reactions, protecting groups are involved to temporary mask reactive groups on both N α-position and side chain of the amino acid. Fmoc is one of commonly used N α-position protecting group, which advantages are quiet obvious. For instance, the deprotection condition with 20–50% piperidine in DMF is truly mild; and the protection scheme with the side chain of different amino acid is orthogonal. Moreover the progress of each deprotection reaction can be followed by real time spectrophotometric monitoring the release of the cleaved Fmoc-group at 300-320 nm. After the desired peptide is synthesized, the resin bound peptide is deprotected and detached from the solid support via TFA cleavage since Fmoc-strategy uses acid liable linkers.
What is the best way to dissolve peptides?
The solubility of a peptide varies depending on its amino acid sequence and modifications. We purify peptides by HPLC using a water and acetonitrile gradient. There are some general comments for dissolving peptides:
Sonication will increase solubility.
Add 10% ammonium bicarbonate to your solvent to help dissolve acidic peptides.
Add 10% acetic acid to your solvent to help dissolve basic peptides.
Try adding organic solvents (such as DMSO, isopropanol, methanol, or acetonitrile) first for extremely low solubility of peptides in aqueous solutions. Once the peptides are dissolved, water may be gradually added until the desired concentration is obtained.
Do you have ISO 9001:2008?
Yes, we are ISO certified since 2006.
Please kindly request peptide solubility test when place order if you need the service.