N-Acetyl Selank (Ac-Selank)

N-Acetyl Selank is Selank carrying an acetyl group on the free alpha-amino nitrogen of its N-terminal threonine, a single change that removes one positive charge at neutral pH and caps the residue aminopeptidases cleave first. The sequence is unchanged: Thr-Lys-Pro-Arg-Pro-Gly-Pro becomes Ac-Thr-Lys-Pro-Arg-Pro-Gly-Pro. The acetylated peptide has the formula C35H59N11O10 and a molecular weight of 793.9 g/mol, against C33H57N11O9 and 751.9 g/mol for Selank, a difference of about 42 mass units. The Pro-Gly-Pro tail protecting the parent’s C-terminus carries over, so this form is capped at both ends.

The modification is not trivial for this sequence. Selank’s first four residues are tuftsin, Thr-Lys-Pro-Arg, whose free N-terminal threonine amine is a defining structural feature, and acetylation caps exactly that group. The analogue is best treated as a distinct molecule, not a stabilised presentation of the parent. No public CAS number is listed for it; PubChem holds one record, CID 133082488. The product listed here is described as an N-acetylated analogue with no C-terminal amide, so this page covers the acetylated free acid, supplied as lyophilized (freeze-dried) powder for laboratory research use only.

Selank was developed at the Institute of Molecular Genetics in Moscow as a proteolytically stabilised tuftsin analogue, its Pro-Gly-Pro tail added to slow degradation from the C-terminal end. The acetylated variant applies the same logic to the other end and entered circulation as a research chemical, not through a design paper.

The published record belongs to the parent alone. Vyunova and colleagues described Selank as a positive allosteric modulator of GABA binding in brain membrane preparations (PubMed 30255741). Sarkisova and colleagues examined it in rat and mouse behavioural models in 2008 (PubMed 18661785), and Kolik and colleagues reported hippocampal BDNF measurements (PubMed 31625062).

There is no indexed primary literature on N-Acetyl Selank under that name, and that is the plain statement a researcher needs. A PubMed search on the acetylated compound returns nothing. Every published Selank finding, binding and behavioural alike, was generated with the unmodified parent, and no study has compared the two.

No mechanism has been published for N-Acetyl Selank itself, so what can be stated is structural rather than pharmacological. Acetylation removes the free alpha-amino group, changing the charge state there and blocking aminopeptidase cleavage. On the sibling peptide Semax the same modification altered copper(II) coordination geometry and the redox behaviour of the complex (PubMed 27586814), showing that N-terminal capping is a real chemical change, not an inert tag.

The distinction worth flagging is with the parent. Selank’s reported binding activity is described for the free-amine peptide, and the tuftsin fragment at its N-terminus is what acetylation modifies, so carrying a Selank result across is an untested assumption. A second is with N-Acetyl Semax, the same modification on a different parent, sharing none of Selank’s sequence beyond the Pro-Gly-Pro tail.

The methodology caveat here is unusually simple: there is no assay to caveat. Any mechanistic statement is an inference from parent-peptide data and acetylation chemistry, and belongs in a study design labelled that way.

Sealed lyophilized N-Acetyl Selank is stored at -20°C, shielded from light, in the unopened container. No duration is asserted here: the stability window for a batch is on its Certificate of Analysis.

Lyophilized material is hygroscopic, meaning it takes up atmospheric moisture, so a container reaches ambient temperature before opening. Freeze-thaw cycling is avoided. There is no disulfide bond here, but the threonine hydroxyl and arginine guanidinium leave the chain pH-sensitive and heat-sensitive.

Reconstitution is the term for returning a lyophilized compound to solution; this page defines it and gives no procedure. N-Acetyl Selank is a short, strongly basic sequence in the aqueous solubility class, and acetylation removes one ionisable group without changing that.

Solid material is handled in low humidity with minimal open-container exposure. Basic peptides adsorb to glass and plastic at low concentration, a known source of loss. Preparation parameters belong to the cited methodology and the lot COA.

Identity and purity for this heptapeptide are established by reverse-phase high-performance liquid chromatography and mass spectrometry, the primary check being a mass consistent with 793.9 g/mol. Verified purity is documented per lot on the Certificate of Analysis.

One quality question is specific to this molecule, and mass alone will not answer it. Selank carries a lysine at position two, so acetylation on that side-chain amine gives the same formula and mass as acetylation on the alpha-amino terminus. Separating them needs tandem mass spectrometry sequencing. Counter-ion content and residual water set fill weight against net peptide, recorded on the COA.

N-Acetyl Selank is catalogued with short peptides studied in neuro research models.

• Selank.
  The unmodified parent and the source of every finding quoted here.
• N-Acetyl Semax.
  The same acetylation on the other Russian heptapeptide stocked here.
• Semax.
  An ACTH(4-10) analogue sharing the Pro-Gly-Pro tail and nothing else.
• DSIP.
  A natural nonapeptide studied in the same research context.

Vyunova TV, Andreeva L, Shevchenko K, Myasoedov N (2018). Peptide-based anxiolytics: molecular aspects of heptapeptide Selank activity. Protein Pept Lett.
PubMed 30255741

Sarkisova KIu, Kozlovskii II, Kozlovskaia MM, et al. (2008). [Effects of heptapeptide selank on genetically-based and situation-provoked symptoms of depression in behavior in WAG/Rij and Wistar rats, and in BALB/c mice]. Zh Vyssh Nerv Deiat Im I P Pavlova.
PubMed 18661785

Kolik LG, Nadorova AV, Antipova TA, et al. (2019). Selank, Peptide Analogue of Tuftsin, Protects Against Ethanol-Induced Memory Impairment by Regulating of BDNF Content in the Hippocampus and Prefrontal Cortex in Rats. Bull Exp Biol Med.
PubMed 31625062

Magri A, Tabbi G, Giuffrida A, et al. (2016). Influence of N-terminus acetylation of Semax on copper(II) coordination. J Inorg Biochem.
PubMed 27586814

Peptides.com lists one N-Acetyl Selank research product, a sealed lyophilized vial from Verified Peptides at a 30mg fill. That per-vial strength is a product specification, not a research quantity. Vials are the only format listed here; the parent is stocked as vials and a liquid spray. Each lot ships with a published Certificate of Analysis.

• Browse all N-Acetyl Selank research products

• Verified Peptides N-Acetyl Selank, 30mg lyophilized vial

Collections: Research Vials. Documentation: COA and Lab Testing.

These products are sold for Research Use Only and are not intended for human consumption.