SNAP-8: structure and analysis

What it is

SNAP-8 is acetyl octapeptide-3: an eight-residue sequence extended from the hexapeptide argireline, carrying an acetyl group on its N-terminus.

Two structural features define it. The extension from six residues to eight, and the N-terminal acetylation — a small chemical modification that caps the free amine at the start of the chain.

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 eight-residue chain and the presence of the N-terminal acetyl group. Acetylation adds forty-two mass units, so the acetylated and non-acetylated species are clearly distinguishable.

That distinction is the identity question specific to this compound: the non-acetylated octapeptide is a different molecule, and its presence is a detectable impurity rather than an invisible one.

Analytical considerations

Incomplete acetylation is the characteristic impurity, and the forty-two-unit mass difference makes it straightforward to detect and quantify — a favourable position compared with the roughly one-unit differences involved in C-terminal amidation.

Acetylation also increases hydrophobicity by capping a charged terminus, so the acetylated and non-acetylated forms separate reasonably well on a reversed-phase method. Mass and retention agree, which is the ideal arrangement.

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.