N-Acetyl Selank Amidate

The base Selank story is a stability story: Russian researchers bolted a Pro-Gly-Pro tail onto tuftsin so the tetrapeptide would survive long enough in plasma to read out behaviour. N-Acetyl Selank Amidate is the next step in that same argument. It takes the seven-residue Selank sequence (Thr-Lys-Pro-Arg-Pro-Gly-Pro) and protects both ends of the chain with standard peptide-chemistry caps. The N-terminus carries an acetyl group, the C-terminus carries a primary amide, and the rest of the molecule is identical to base Selank. The rationale: the central core has the pharmacology, the unprotected ends are where exopeptidases bite first.

What the two end-caps actually do

Free peptide N-termini are the substrate for leucine aminopeptidase and the wider aminopeptidase family, which chew one residue at a time off the front of the chain. Free C-termini with an exposed carboxylate are the substrate for carboxypeptidases doing the same thing from the other end. Replacing the N-terminal amine with an acetamide (Ac-) removes the recognition motif for the aminopeptidases. Replacing the C-terminal carboxylate with a primary amide (-CONH2) removes the recognition motif for the carboxypeptidases. The strategy is one of the older tricks in medicinal peptide chemistry, used across releasing hormones, GLP analogues, and several oxytocin-family compounds. Applied here, it lengthens the in vitro window in which intact Ac-TKPRPGP-NH2 is still measurable before clearance.

How this variant relates to base Selank

Pharmacology first, chemistry second: the residues the literature thinks are doing the work (the tuftsin-derived TKPR head and the proline-rich tail that holds shape) are unchanged. The GABAergic and enkephalinase-related effects reported for base Selank in rodent and ex vivo studies sit on the same TKPRPGP sequence this molecule presents. What the end-caps change is how long the intact molecule stays intact under enzymatic load. Several authors describe the capped analogue as a longer-lasting variant suitable for protocols where the unprotected parent peptide clears too quickly to give a clean readout. Whether the improvement extends to in vivo blood-brain-barrier transit is still an open question, and we will not overstate it.

Specifications per lot

• Lyophilised Ac-TKPRPGP-NH2 in a sealed glass vial, inert-gas flushed before crimp sealing
• Mass to within 1 Da of the expected 793.9 g/mol for the capped heptapeptide
• Reverse-phase HPLC at 98 percent or better with the mass-spec trace recording the +42 (acetyl) and -1 (amide vs free acid) signatures that distinguish this analogue from base Selank
• Batch-specific Certificate of Analysis matched to the lot number on the label

Where the material is sourced

We stock N-Acetyl Selank Amidate from UK and EU contract peptide houses we have audited. The reason for the geographic restriction is the same reason it applies to base Selank: the silent failure mode in the unverified market is counter-ion drift and occasional sequence misidentification, either of which corrupts a binding or anxiolysis readout before anyone notices the bottle was wrong. UK orders placed Monday to Thursday afternoon ship the same working day, and roughly nine in ten arrive inside 48 hours. If a vial fails its CoA on arrival, we refund it.

Bench handling

The lyophilised solid is stable through ambient transit, but move it to minus 20 C for any storage past a week. After reconstitution in bacteriostatic water, refrigerate and use within two to three weeks where peptide integrity is load-bearing. The end-caps slow exopeptidase clearance, not all degradation, so freeze-thaw cycling still damages the active peptide. For ten or more vials, message support for a bulk quote. Live chat in UK hours reaches the people who handle the stock.

Sold strictly for in vitro laboratory research. Not for human or veterinary use. UK 18+.