Peptide Synthesis

How do our prices compare to those of our competitors?
Our prices are quite competitive and in accordance with prices from other Peptide Suppliers. It has to be taken into consideration that the price depends very much on the quality of the final product. The critical manufacturing step, to reach a good quality, is the purification, that is the most expensive and time-consuming step. The more a peptide is difficult, the more the purification will be complicated and, as a conseguence, the more the peptide will be expensive.

Is there any limitation on the length of peptides?
Sequences less than 4 amino acids can be really problematic during the cleavage and the purification. For this reasons, we prefer to evaluate sequences < 5 amino acids. We don’t make dimers. Orders of peptides between 8 up to 25 amino acids in length are always accepted. Primm will also synthesize sequences up to 40 residues and quotes will reflect the quantity and the purity requirements. For longer sequences, please inquiry. 

What quantity are we able to produce?
Primm can produce peptides from mg to grams and at different purity levels from crude to 95-98% pure. 

What if Primm does not succed in making the requested peptide?
Primm accepts any order for peptides not longer than 25 amino acid residues. If one sequence cannot be made, Primm will inform the customer in approximately 1 week from the order, suggesting eventual modifications to the sequence. Of course, if the sequence cannot be made, any cost will be charged. For sequences longer than 25 amino acids, Primm staff must see them before accepting the order and the acceptance will be communicated within 24 hours. Again, if Primm won’t be able to make the peptide, the customer won’t be requested to pay any fee. To give you a realistic estimation, the synthesis failure at Primm labs, for peptides shorter than 25 aa, is less than 3%.

What purity levels are available and what’s the best purity level for my application?
Primm offers different purity levels starting with > 70% up to > 95%, but it’s also possible an ultra pure level (> 98%) upon request.
Please, refer to the following guideline, to select the most suitable grade of purity for your application:

• non-sensitive screening assays: crude or purity >70%
• immunological applications: purity > 70%
• receptor/ligand studies, bio-assay studies or cell studies (e.g. cellular activation / drug screening in cell culture): purity >95%
• structural studies (NMR, X-ray, MS): purity >95%

If my peptide is 95% pure, what is in the other 5%?
Peptide purity is determined by reverse-phase HPLC. As a limit of peptide synthesis method (= solid phase synthesis), the coupling reaction of one amino acid to another is not always 100% efficient, causing a variety of deletion sequences to be generated. Most of the deletion sequences are purified out, but a few, having similar chromatographic characteristics to the target peptide, remain in the peptide sample and account for the percent of impurities. 

All peptides are supplied lyophilized, unless differently requested. The lyophilized solids should be stored at -20�C (or even better at -80�C) for long time or at +4�C for short time (< 3 months). When solubilized should be stored at -20�C / -80�C for short time (< 3 months). 

What Quality Control information is supplied?
With the exception of crude peptides , which will only be checked by MALDI-MASS spectrometry, all synthetic peptides will be analyzed by HPLC and MS to verify composition and purity. The QC documentation is supplied for every peptide and is enclosed to the peptide-vial.

How long does it take from order to shipment?
The manufacturing steps of the peptide-production: synthesis, purification and QC analysis require almost 3 weeks. For very long or hard sequences the production should take up to 4/5 weeks. 

What type of chemical modification does Primm provide?
We offer mostly of the commercially available modifications such as: Biotin, Fluorescein, Rhodamin, isotopic amino acids, MAP 2 or 4 branched, Phosphorylated residues, Spacers-Linkers, Cys-Cys or head-tail Cycles. We can supply also other modifications upon request. 

How do I dissolve the peptide?
The solubility information is reported on the data sheet enclosed to the peptide. Please, read this carefully before starting. The solubility greatly depends on various parameters (the primary and second structure, the alternation of neutral, hydrophobic and charged amino acids, the nature of the modifications made, the solvent and so on.). Therefore it’s quite impossible to predict the real solubility of the peptide before its actual production.

Please, consider the following suggestions.
As a general role, always begin by reconstituting a small amount of peptide before committing the entire lot. The most common dissolution process is 1 mg of peptide dissolved in 1 mL of sterile water (avoid reconstituting a peptide in a buffer, such as PBS because salts hinder the solubility). If the small amount of peptide is not perfectly solubilized in that conditions (= just water), try the following steps on the left peptide:

• Sonication is helpful to dissolve
• Small amounts of dilute (max 10%) aqueous acetic acid for basic peptides and aqueous ammonia for acidic peptides may help
• Choose the appropriate solvent. Begin reconstituting at a concentration higher than your desired final working concentration (only after the complete dissolution of the peptide, add water or buffer to reach the desired final concentration; note: salts may cause aggregation!)
• H2O: for hydrophilic residues (K-R-H-D-E-N)
• Organic solvents: DMF, DMSO, Acetonitrile or TFA: for hydrophobic residues (A-V-L-I-M-F-W)