# Kisspeptin Peptide: Structure, Isoforms, and Discovery — About This Site

> Kisspeptin peptide — KISS1 gene, isoforms KP-10 and KP-54, discovery history from melanoma suppressor to reproductive master switch — and about this independent research digest.

## Kisspeptin Peptide: Structure and Isoforms

The kisspeptin peptide family is encoded by the KISS1 gene. The gene produces a 145-amino-acid precursor protein that is processed to yield four principal fragments: KP-54 (54 amino acids), KP-14, KP-13, and KP-10. All four isoforms share a conserved C-terminal decapeptide sequence ending in the RF-amide motif (Arg-Phe-NH2) required for KISS1R binding. The minimal fully active fragment is KP-10 (Tyr-Asn-Trp-Asn-Ser-Phe-Gly-Leu-Arg-Phe-NH2; molecular weight 1302.5 Da). [1][4]

KP-54 (molecular weight 6142 Da) is the primary endogenous isoform detected in human plasma. Its larger size provides approximately 8-fold greater resistance to endopeptidase cleavage compared to KP-10, accounting for the half-life difference (~32 min versus ~4 min). [12]

## How was kisspeptin discovered?

The KISS1 gene was cloned in 1996 at the Milton S. Hershey Medical Center in Hershey, Pennsylvania, as a melanoma metastasis suppressor gene. KISS1 transfection suppressed metastasis by more than 95% in nude mice (Lee 1996, J Natl Cancer Inst). [17]

The reproductive role was identified in 2003. Seminara et al. (NEJM) identified inactivating GPR54 mutations in patients with idiopathic hypogonadotropic hypogonadism and absent puberty, and confirmed the phenotype in Gpr54-knockout mice. [1]

## What is the KISS1 gene?

KISS1 (Gene ID: 3814) is located on human chromosome 1q32. It encodes the 145-amino-acid kisspeptin precursor protein. KISS1 expression in the hypothalamus is concentrated in KNDy neurons in the arcuate nucleus and neurons in the anteroventral periventricular nucleus. [15]

## About Kisspeptin Research

Kisspeptin Research is an independent editorial project that publishes summaries of the peer-reviewed research literature on kisspeptin. We are not a clinic. We do not provide medical advice. We do not manufacture, sell, or distribute any product.

Every quantitative claim on this site is cited to a peer-reviewed source. Full citation index at /references.

## References

[1] Seminara SB, et al. The GPR54 Gene as a Regulator of Puberty. NEJM. 2003. https://www.nejm.org/doi/full/10.1056/NEJMoa035322
[3] Topaloglu AK, et al. Inactivating KISS1 Mutation and Hypogonadotropic Hypogonadism. NEJM. 2012. https://pubmed.ncbi.nlm.nih.gov/22335740/
[4] Liu X, Lee K, Herbison AE. Kisspeptin excites GnRH neurons through a PLC/calcium-dependent pathway. Endocrinology. 2008. https://pubmed.ncbi.nlm.nih.gov/18483150/
[12] d'Anglemont de Tassigny X, et al. Mechanistic insights into KP-54 vs KP-10. PLoS One. 2017. https://pmc.ncbi.nlm.nih.gov/articles/PMC5413024/
[15] Goodman RL, et al. Kisspeptin, Neurokinin B, and Dynorphin Act in the Arcuate Nucleus. Endocrinology. 2013. https://pubmed.ncbi.nlm.nih.gov/23959940/
[17] Lee JH, et al. KiSS-1, a novel human malignant melanoma metastasis-suppressor gene. J Natl Cancer Inst. 1996. https://pubmed.ncbi.nlm.nih.gov/8944003/
[19] Dos Santos E, et al. KISS1/KISS1R in Cancer: Friend or Foe? Frontiers in Endocrinology. 2018. https://pmc.ncbi.nlm.nih.gov/articles/PMC6085450/

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The KISS1 record — mechanism, isoforms, and clinical trials — indexed here. Not a clinic, not a vendor.