Selank

What is Selank?

Selank is a synthetic linear heptapeptide with the amino acid sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro. The chain consists of a naturally occurring tetrapeptide motif (Thr-Lys-Pro-Arg) to which the tripeptide Pro-Gly-Pro is attached at the C-terminus. The compound bears CAS number 129954-34-3 and has the molecular formula C₃₃H₅₇N₁₁O₉ and a molecular mass of approximately 751.9 Da (PubChem CID 11765600).

With three proline residues at seven positions, Selank is a distinctly proline-rich sequence. Proline limits the rotational freedom of the backbone, and the proline-glycine-proline sequence at the C-terminal end increases the rigidity of that end, thereby limiting attack by exopeptidases; under laboratory conditions, this makes the chain measurably more stable than the unextended tetrapeptide motif, which degrades rapidly in defined buffer systems. Furthermore, two strongly basic residues—lysine and arginine—give the molecule a high isoelectric point and a distinctly hydrophilic character, while the chain contains no aromatic residues whatsoever. Consequently, detection relies not on absorption at 280 nm, but on the peptide bond itself around 210–220 nm. This combination of chain rigidity, high hydrophilicity, and the absence of a chromophore makes Selank an instructive model compound in comparative peptide research and in the development of analytical methods.

Applications in a laboratory context

Within peptide chemistry and analytical work, Selank is involved in the following in vitro research areas, among others:

• Structure-activity relationship research to the contribution of the Pro-Gly-Pro terminus, where the extended sequence alongside the unextended tetrapeptide motif is characterized for chain rigidity, charge profile, and chromatographic behavior.
• Peptide chemistry research regarding the behavior of short, proline-rich, and highly hydrophilic chains: solubility, retention in reverse-phase chromatography at low organic fraction, and cis-trans isomerism around the proline peptide bond as a source of peak broadening.
• Enzymatic stability studies in which the degradation rate by amino- and carboxypeptidases is monitored in defined buffer systems and the resulting fragments are assigned by mass spectrometry.
• Analytical method development and validation (HPLC, LC-MS, peptide mapping) where Selank serves as the reference standard for sequences without an aromatic chromophore, with detection on the amide bond in far UV and with mass spectrometric identity confirmation.

Specifications

Shape, handling and storage

The material is supplied as freeze-dried powder (lyophilisate) in a sealed glass vial with a septum and shrink cap. The lyophilisate is white to off-white and presents as a compact cake or as a fine powder; both are normal appearances of the freeze-drying process. The material is hygroscopic — all the more so in a strongly hydrophilic, basic sequence — and therefore remains closed in the original packaging until it is processed in the laboratory.

Store the unopened lyophilized lyophilized powder refrigerated at 2–8 °C, in a dry and dark place, protected from light and moisture; for longer storage periods, it is usually stored frozen. Allow the vial to reach room temperature before opening to minimize condensation, work in a clean environment, use appropriate personal protective equipment, and prevent cross-contamination with other laboratory materials. Dispose of residual material in accordance with applicable laboratory guidelines.

Analytical quality

For short, proline-rich chains, identity and purity are the determining parameters: shortened chains and deletion variants differ only slightly in retention, and the absence of an aromatic chromophore places additional demands on detection. Our Selank is supplied with a purity of ≥ 99%, determined by HPLC analysis in accordance with the corresponding certificate of analysis. The available certificates of analysis can be viewed on our website. lab results page.

Important disclaimer

We supply this product strictly for laboratory research and analytical work. It is not intended for diagnostic or therapeutic applications, and expressly not for use in humans or animals. This product is not a foodstuff, a supplement, a cosmetic product, or a registered medicinal product. By purchasing this product, the purchaser confirms that they are 18 years of age or older and will use the product exclusively within a controlled research or laboratory environment.