Kisspeptin-10: structure and analysis

What it is

Kisspeptin-10 is the ten-amino-acid C-terminal fragment of kisspeptin, the peptide product of the KISS1 gene. The parent peptide is considerably longer; this fragment is the portion that carries the activity, which is why it is the form supplied.

It belongs to the RFamide family, meaning it terminates in arginine-phenylalanine with the C-terminus present as an amide rather than a free acid. The sequence also contains a tryptophan residue.

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 ten-residue chain and, importantly, the C-terminal amide. The amide and the free acid differ by roughly one mass unit, which is a small difference requiring high-resolution measurement to resolve confidently — and a difference that matters, because the free-acid form is a distinct compound.

Analytical considerations

The tryptophan residue is the analytically significant feature. Tryptophan is among the most readily oxidised and most light-sensitive amino acids, so oxidation products are a plausible impurity class and light protection is a reasonable handling precaution.

Incomplete C-terminal amidation is the other characteristic impurity, and because it produces only a small mass shift, it is a result that depends on the resolution of the identity method rather than being obvious from a low-resolution spectrum.

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.