Selank: structure and analysis

What it is

Selank is a synthetic heptapeptide: a seven-residue analog of the endogenous tetrapeptide tuftsin, extended with a stabilising tripeptide tail.

The design is straightforward and worth understanding, because Semax follows the same logic. A short active sequence is joined to a proline-glycine-proline tail whose function is to slow enzymatic degradation of the parent fragment.

The result is proline-rich, which constrains the backbone conformation more than a sequence of flexible residues would.

How it is produced

Assembled by solid-phase peptide synthesis: the chain is built one residue at a time on an insoluble resin support, then cleaved from the resin, deprotected and purified — most commonly by reversed-phase high-performance liquid chromatography. The purified material is lyophilized to a dry solid.

The impurity profile that appears on a certificate is a record of where that process was imperfect: deletion sequences from an incomplete coupling, truncated chains, and species retaining a protecting group.

Confirming identity

Mass spectrometry confirms the full seven-residue chain including the tripeptide extension. A species consisting of the tuftsin fragment alone — the extension absent or cleaved — has a substantially lower mass and is an unambiguous impurity.

Analytical considerations

The sequence contains no methionine, cysteine or tryptophan, which means the oxidation and photodegradation pathways that dominate for Semax, MOTS-c and Kisspeptin-10 are not the principal concerns here. This is a genuinely more chemically robust sequence than its counterpart Semax.

Proline-rich peptides can show unusual chromatographic behaviour, including peak broadening arising from slow interconversion between cis and trans amide conformations. It is a method-development consideration rather than a purity problem.

What its certificate reports

A certificate for a lot of this material names the lot, names the issuing laboratory, and states for each parameter both the method used and the specification the result was measured against. Identity and purity are the two core results; net peptide content states how much of the fill weight is actually peptide.

A certificate belongs to a lot, not to a product line. When a new lot is released it is tested again, and the certificate published against it is that lot's certificate — a previous lot's result is never carried forward.

Research use only

This page describes structure and analysis. It makes no claim about what this compound does, and none should be inferred from it. Material is supplied for laboratory research use only: it is not a drug, food, dietary supplement, cosmetic or medical device, it is not for human or veterinary consumption, and no dosing, administration or reconstitution guidance is provided for any such use.