Kisspeptin-10

1 Identity

Synthetic C-terminally amidated decapeptide, all-L and entirely proteinogenic. An RFamide: the C-terminal primary amide is definitional, not a refinement. Not synonyms and each is a different molecule: kisspeptin-13, kisspeptin-14 and kisspeptin-54 (metastin, CAS 374683-24-6) are longer fragments of the same 145-residue precursor.

Sequence

H-Tyr-Asn-Trp-Asn-Ser-Phe-Gly-Leu-Arg-Phe-NH2; one-letter YNWNSFGLRF-NH2. Ten residues, all-L, entirely proteinogenic, free N-terminal alpha-amine. The C-terminal primary amide is obligatory: this is an RFamide, and the free-acid form is a different article rather than a lesser grade of this one. No cysteine, no disulfide, no non-proteinogenic residue and no D-residue - stated explicitly so that P3 is not applied by reflex, and so that the certificate's declaration that no chiral method was run is a disclosure rather than a gap. Two protonatable sites, the Arg9 side chain and the N-terminal amine, so the salt is normally a bis-salt and the counterion is a material share of gross vial weight. Made by solid-phase chemical synthesis; it is not cleaved from anything, notwithstanding that the same ten residues occur as the C-terminal decapeptide shared by the KISS1 gene products kisspeptin-54, -14 and -13, all of which are proteolytic fragments of a 145-residue precursor. Three residues govern the release panel: Trp3 is photo- and peroxide-labile; Asn2 and Asn4 deamidate, and the Asn-Trp and Asn-Ser sequences are moderate-rate contexts for it.

Molecular formula

C63H83N17O14 (free base, C-terminal amide). Bis-acetate C67H91N17O18; mono-trifluoroacetate C65H84F3N17O16; bis-trifluoroacetate C67H85F6N17O18.

Average mass

1,302.46 Da (C63H83N17O14). On IUPAC 2021 abridged conventional atomic weights the formula gives 1,302.462. On the older pre-2021 conventional set the same formula gives 1,302.44. Listings print 1,302.44, 1302.45 and 1302.5 - the same figure at four different precisions and on two different tables, and no disagreement about the molecule. Bis-acetate 1,422.57; mono-trifluoroacetate 1,416.49; bis-trifluoroacetate 1,530.51, of which 14.9 percent of the gross weight is counterion.

Monoisotopic mass

1,301.6305 Da neutral. [M+H]+ 1,302.6378, which is the number the identity test reports against the plus or minus 10 ppm limit - a window of plus or minus 0.013 Da. [M+2H]2+ 651.8225. One collision belongs in this field rather than in A footnote: the des-amido free acid has a neutral monoisotopic mass of 1,302.6146, which sits 0.0232 Da - about 18 ppm - from this peptide's protonated ion at 1,302.6378. A certificate reporting '1302.6' without naming the charge state and the adduct has not distinguished the product from its commonest impurity.

Salt / variant note

Six distinct molecules, one naming trap, and two exact isobars that no mass measurement will resolve. (1) human KP-10, YNWNSFGLRF-NH2, C63H83N17O14, 1,302.46 average / 1,301.6305 monoisotopic - the intended article. (2) murine (mouse, rat) KP-10, YNWNSFGLRY-NH2, C63H83N17O15, 1,318.46 / 1,317.6255, CAS 478507-53-8, with listings for it printing C63H83N17O15 and a formula weight of 1318.4. It differs by one terminal residue, Tyr for Phe, and by 16.00 Da, and is not separable from the human sequence by reversed-phase retention alone. (3) Trp3 oxidation turns this peptide into an exact isobar of the murine sequence: mono-oxidation of Trp3 to hydroxytryptophan adds one oxygen, giving the human peptide the formula C63H83N17O15 - which is the murine peptide'S formula, atom for atom. Oxidized human KP-10 and native murine KP-10 have identical average masses (1,318.46) and identical monoisotopic masses (1,317.6255) to every decimal place. The panel's murine-exclusion limit and its Trp-oxidation limit are therefore the same number, and neither is a mass test: only MS/MS fragment assignment through the C-terminus, or retention against both qualified standards, separates a degraded human lot from a correct murine one. (4) A second exact isobar: the des-amido free acid C63H82N16O15, 1,303.45 / 1,302.6146, and a singly deamidated Asn-to-Asp species have the identical formula and mass, because hydrolysis of the C-terminal amide and deamidation of Asn2 or Asn4 are the same +0.984 Da transformation. Three chemically distinct events land on one number, so a certificate limiting 'des-amido free acid at 1,303.4' has not distinguished them and must resolve them chromatographically. (5) Trp3 to kynurenine, C62H83N17O15, 1,306.45 / 1,305.6255, +3.99 Da. Di-oxidation C63H83N17O16, 1,334.46 / 1,333.6204. (6) salts: bis-acetate C67H91N17O18, 1,422.57 / 1,421.6728; mono-trifluoroacetate C65H84F3N17O16, 1,416.49 / 1,415.6234; bis-trifluoroacetate C67H85F6N17O18, 1,530.51 / 1,529.6163. (7) longer fragments of the same precursor: kisspeptin-13 (human), PubChem CID 44419636 gives C78H107N21O18; kisspeptin-54 (metastin), CAS 374683-24-6, a 54-residue peptide whose formula is not established here and for which no mass is stated. The naming trap restated because it defeats a correct CAS: two suppliers list 'Kisspeptin-13 (4-13) (human)' under CAS 374675-21-5, which is kisspeptin-10's CAS, so a purchase order written against a product name, or even against a name plus CAS, can land on any of these. Only a residue-level sequence with the species named cannot.

2 Class & testing panel

Form

Single article

Testing panel

P1 — panel definition

3 Primary sources & evidence

The index reports the design and provenance of the literature, not a conclusion about effect.

Published literature exists and is substantial in animals. A large rodent and non-human-primate endocrine-physiology literature, on the order of several hundred primary reports accumulated since the KISS1 receptor was deorphanized in 2001, plus a large in-vitro receptor-pharmacology file. Human literature consists of small single-center investigator-initiated physiology studies, typically fewer than forty participants, concentrated in a small number of academic groups and registered as physiology rather than as efficacy studies. There is no Phase 3 program, no approved product in any jurisdiction, and no independent large-n human dataset. Registered analogues developed by pharmaceutical sponsors are distinct molecules and their trial results are indexed separately and flagged as not transferable to the native decapeptide - the same attribution rule that governs the humanin and IGF records in this catalog. A second attribution rule is specific to this molecule and is enforced on the citation index page: a large share of the animal literature used the murine decapeptide, which is a different molecule 16.00 Da heavier, so each reference carries a field recording which species' sequence was administered. Where a study's methods do not name the species, the entry is left unresolved rather than assumed.

4 Storage & specification

Storage

Supplied as an off-white to pale lyophilized powder, acetate salt, in a screw-cap amber borosilicate vial with a PTFE-lined closure - a laboratory-chemical presentation, not a stoppered and crimped injection vial, non-sterile, with no sterility claim. Store at -20 degrees C plus or minus 5 degrees C, desiccated and protected from light. Light protection is A specification requirement here and not A convention, because Trp3 is photo-oxidizable and its oxidation product is isobaric with the murine peptide the panel exists to exclude - so a light excursion does not merely degrade the article, it degrades it into something a mass measurement will misread as a different species. Vials ship in opaque secondary packaging and are equilibrated to room temperature before opening. Keep away from peroxide-forming solvents and from oxidizing agents; ethers and aged tetrahydrofuran are not used anywhere near this article. Hygroscopic as the bis-salt. Reconstituted solution is aliquoted single-use and held at -80 degrees C, protected from light at every step including during handling. Ships ambient with a labeled cumulative excursion allowance and a single-use temperature logger in every export carton.

Shelf life

Provisional retest interval 24 months from release at -20 degrees C plus or minus 5 degrees C, desiccated and light-protected. Provisional pending company stability data on the first three commercial lots under an ICH Q1A(R2)-style protocol - 12 months real time with pulls at 0, 3, 6, 9 and 12 months, plus 6 months accelerated at 40 degrees C / 75 percent relative humidity - with the stability-indicating method reporting Trp-oxidation and Asn-deamidation species individually rather than as a total, because on this molecule each of those two families collides with a different identity question. A photostability arm per ICH Q1B is run on the first lot specifically to fix the light-protection requirement with data rather than with a convention. Extension beyond 24 months only on real-time data from three commercial lots. Printed retest date on every vial and first-expiry-first-out enforced against that date rather than against receipt date; material passing retest is re-dated for a further 12 months, material failing is destroyed and the destruction is recorded.