Selank — a tuftsin analog, and the tail it shares with Semax
Selank is tuftsin with the same Pro-Gly-Pro tail Semax carries. Two compounds, one structural idea, and no methionine to worry about.
Selank is a seven-residue peptide, CAS 129954-34-3, molecular formula C33H57N11O9, molecular weight 751.88 g/mol. Its sequence is Thr-Lys-Pro-Arg-Pro-Gly-Pro — the tuftsin tetrapeptide carrying the same proline-glycine-proline tail that Semax uses, applied here to a different parent fragment. It contains no sulfur at all.
By the Bench Grade Research Team ·
Selank identity data
| Property | Value |
|---|---|
| CAS Registry Number | 129954-34-3 |
| Molecular formula | C33H57N11O9 |
| Molecular weight | 751.88 g/mol |
| Sequence | Thr-Lys-Pro-Arg-Pro-Gly-Pro |
| Derived from | Tuftsin (Thr-Lys-Pro-Arg) plus Pro-Gly-Pro |
Tuftsin plus the same tail
The first four residues are tuftsin, a naturally occurring tetrapeptide. The last three are the Pro-Gly-Pro tail that Semax also carries — the same stabilising modification applied to a different parent. Seeing the two side by side makes the design obvious in a way that neither does alone.
No sulfur, and what follows from that
The formula C33H57N11O9 contains no sulfur, which means no methionine and no cysteine. Both of the most common chemical degradation routes for peptides are therefore absent — no oxidation shoulder to look for on the chromatogram, and no disulfide scrambling. Compared with Semax, which carries a methionine, this is a materially more robust molecule.
Three prolines in seven residues
Nearly half the sequence is proline. That heavily constrains the backbone, which resists the extended conformations that lead to aggregation, and it is why preparations of this peptide rarely present the fibril problems longer sequences do.
Analysis notes
- No tryptophan or tyrosine, so detection at 280 nm is unavailable; analysis relies on 214 nm.
- Highly water-soluble — a charged short peptide with an arginine and a lysine rarely resists aqueous solvent.
- Short and polar, so it retains poorly on reverse-phase columns and can elute near the void volume where separation is worst. A method developed for this compound places the peak clear of that region.
What the published work examined
One study in our research library, from 2007, concerns mechanisms investigated in a research setting. It is linked below.
References
Primary literature for the compounds discussed above. Links open the record on PubMed.
- Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurasthenia Medvedev VE, et al. Zh Nevrol Psikhiatr Im S S Korsakova. 2007. PMID 18454096 → · summary
- Orally Targeted Delivery of Tripeptide KPV via Hyaluronic Acid-Functionalized Nanoparticles Efficiently Alleviates Ulcerative Colitis Xiao B, et al. Mol Ther. 2017. PMID 28456380 → · summary
- PepT1-mediated tripeptide KPV uptake reduces intestinal inflammation Dalmasso G, et al. Gastroenterology. 2008. PMID 18061177 → · summary
Primary sources
- Efficacy and possible mechanisms of action of a new peptide anxiolytic selank in the therapy of generalized anxiety disorders and neurastheniaZh Nevrol Psikhiatr Im S S Korsakova · 2007
- Orally Targeted Delivery of Tripeptide KPV via Hyaluronic Acid-Functionalized Nanoparticles Efficiently Alleviates Ulcerative ColitisMol Ther · 2017 · animal study
- PepT1-mediated tripeptide KPV uptake reduces intestinal inflammationGastroenterology · 2008 · animal study
Frequently asked questions
- What is Selank derived from?
- Tuftsin — the naturally occurring tetrapeptide Thr-Lys-Pro-Arg — with a Pro-Gly-Pro tail appended. It is the same stabilising tail that Semax carries on a different parent fragment.
- Is Selank more stable than Semax?
- Chemically, yes. Selank's formula contains no sulfur, so it has no methionine and no cysteine — the two most common chemical degradation routes are absent. Semax carries a methionine that oxidises readily.
- Why does Selank contain so much proline?
- Three of its seven residues are proline. That constrains the backbone against the extended conformations that lead to aggregation, and the proline-rich terminal resists enzymatic cleavage.
Compounds discussed in this guide
More on identification
- What is the super human blend? Why there is no standard onea super human blendSuper human blend has no agreed formulation — the same name covers different vials from different suppliers. What is usually in one, what the research covers, and how to compare two of them.
- KLOW and GLOW blends — what is in each and how they differKLOW is GHK-Cu, BPC-157, TB-500 and KPV. GLOW is the same minus KPV. What the fourth component changes and how the totals divide.
- BPC-157 reference — identity, stability, handlingCAS, molecular weight and sequence for BPC-157, why its amino acid composition makes it unusually stable, and what a complete COA should show.
Who publishes this guide
- Who sells it
- Bench Grade Peptides LLC, a US supplier of lyophilized synthetic peptides for laboratory research use only. It works with US manufacturing partners rather than running a facility of its own. Is Bench Grade Peptides legit? →
- Certificates of Analysis
- 139 third-party Certificates of Analysis covering 39 of 44 live products, published per lot in a public library anyone can read before ordering. A very recent lot can appear a few days after it enters the catalogue. COA library →
- Ships from
- Florida, by UPS, to US addresses only (no international shipping). The registered address in Dover, Delaware is the legal address only. Shipping →
- Use
- For laboratory research use only — not for human or veterinary use. Not a drug, supplement or medical device. Compliance and research use →
All products discussed in this guide are supplied by Bench Grade Peptides for laboratory research use only. Not for human or veterinary use.