What is SELANK?
Selank is a synthetic oligopeptide belonging to the peptide class of research compounds. It is cataloged under CAS number 129954-34-3 and carries the molecular formula C33H57N11O9 with a molecular weight of 751.89 g/mol. Its primary structure comprises seven amino acid residues arranged in the sequence Thr-Lys-Pro-Arg-Pro-Gly-Pro (threonine–lysine–proline–arginine–proline–glycine–proline).
Structurally, Selank is recognized as a stabilized analog of tuftsin, a naturally occurring endogenous tetrapeptide (Thr-Lys-Pro-Arg). The Selank heptapeptide extends the tuftsin core with an additional Pro-Gly-Pro tripeptide motif at the C-terminus. This proline-rich extension is a common design strategy in peptide chemistry intended to increase resistance to enzymatic degradation and improve the conformational stability of the molecule relative to the shorter parent sequence. The high proline content contributes to the peptide's characteristic backbone rigidity.
Within the scientific literature, Selank is associated with neuropeptide and peptide-regulator research areas, where synthetic tuftsin analogs are studied as molecular tools in in-vitro and preclinical model systems. It is offered strictly as a reference material for laboratory research and analytical applications. This monograph describes only the chemical identity, handling, and characterization of the material and makes no representation regarding physiological activity or use in humans or animals.
Reconstitution & handling
Selank is supplied as a lyophilized (freeze-dried) powder and is typically reconstituted in the laboratory using bacteriostatic or sterile water to prepare an aqueous stock solution. As a hydrophilic peptide bearing charged lysine and arginine residues, Selank generally exhibits good solubility in aqueous media; the solvent is usually added slowly down the side of the vial and allowed to dissolve without vigorous agitation. Gentle swirling rather than vortexing is preferred, as aggressive mixing and foaming can introduce shear stress at the air–liquid interface.
For handling, the diluent should be directed onto the vial wall and the solution left to stand until the powder fully dissolves into a clear, particle-free liquid. Where a co-solvent is required for a particular workflow, a small fraction of dilute acetic acid or another compatible aqueous vehicle may be used before bringing the solution to final volume, consistent with standard peptide-handling practice. All reconstitution should be performed under clean conditions to preserve sample integrity for downstream analytical work.
Storage & stability
In its lyophilized form, Selank is best stored desiccated and protected from light at −20 °C, conditions under which the dry peptide is stable for extended periods. Once reconstituted into aqueous solution, the peptide is less stable and should be kept refrigerated at 2–8 °C for short-term use or frozen in aliquots at −20 °C or below for longer-term storage. Preparing single-use aliquots minimizes exposure to repeated freeze–thaw cycles, which can promote hydrolysis and aggregation and degrade sample quality. Reconstituted material should be inspected for clarity prior to use.
How it's tested
The identity and purity of Selank are established through standard analytical methods for peptide characterization. Reversed-phase high-performance liquid chromatography (HPLC) is used to quantify chromatographic purity, with this lot characterized at ≥99% by HPLC. Mass spectrometry (MS) confirms molecular identity by verifying the observed mass against the theoretical molecular weight of 751.89 corresponding to the formula C33H57N11O9. Each batch is accompanied by a Certificate of Analysis (COA) documenting the purity result, analytical conditions, and lot-specific data, providing traceable, lot-specific verification of the material's identity and quality.