Compound monograph
Human Octanoyl-Ghrelin
Human octanoyl-ghrelin is the endogenous 28-residue acylated peptide ligand of the ghrelin receptor, carrying an n-octanoyl ester on serine 3.
01
Identity & nomenclature
Human octanoyl-ghrelin is the endogenous 28-residue acylated peptide ligand of the ghrelin receptor, carrying an n-octanoyl ester on serine 3.
'Ghrelin' alone is not a resolved chemical identity. Species, chain length, acylated versus desacyl, and the acyl chain itself must all be specified. Desacyl-ghrelin is a different substance, not the same one differently formulated.
Declared aliases and development codes: Lenomorelin, Human acyl-ghrelin, Acyl-ghrelin.
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Molecular properties
| Molecular formula | C149H249N47O42 |
|---|---|
| Molecular mass | 3370.92 Da |
| CAS Registry Number | 258279-04-8 |
| PubChem CID | 91668172 |
| UNII | UXG268Q86R |
| One-letter sequence | GSSFLSPEHQRVQQRKESKKPPAKLQPR |
Twenty-eight residues, all L. The backbone string is NOT a complete identity: the Ser3 side-chain hydroxyl is esterified with n-octanoic acid, and that ester is required for canonical receptor activation. A registry synonym for this substance omits a lysine while a correctly specified 28-residue synonym sits alongside it — do not regard every registry synonym as equally authoritative.
03
Structural characteristics
Cryo-EM structures of the ghrelin receptor bound to ghrelin and to the synthetic secretagogue GHRP-6 reveal a distinct pocket accommodating the octanoyl group, which positions the peptide for receptor activation rather than serving only as a half-life extension. The strong requirement for acylation in canonical activation should not be restated as desacyl-ghrelin having no biological activity of any kind; that broader claim is not established by these receptor experiments.
- Ser3 O-n-octanoylation
Terminal features: Free Gly1 amino terminus, Free Arg28 carboxyl terminus.
04
Molecular targets & mechanisms
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Analytical considerations
Identity work must preserve and measure the Ser3 ester, not merely confirm a ghrelin backbone. Loss of the octanoyl changes the neutral composition by C8H14O, 126.1045 Da; monitoring that product reveals deacylation but does not establish that the original ester was on Ser3. An immunoassay recognising a retained epitope settles neither acylation nor chain length.
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Verified bibliography
- 1H NMR structural analysis of human ghrelin and its six truncated analogs.current
Silva Elipe MV, Bednarek MA, Gao YD
Biopolymers · 2001-12 · Journal Article
- Ghrelin is a growth-hormone-releasing acylated peptide from stomach.current
Kojima M, Hosoda H, Date Y, Nakazato M, Matsuo H, Kangawa K
Nature · 1999-12-09 · Journal Article
- Molecular recognition of an acyl-peptide hormone and activation of ghrelin receptor.current
Wang Y, Guo S, Zhuang Y, Yun Y, Xu P, He X, Guo J, Yin W, Xu HE, Xie X, Jiang Y
Nature communications · 2021-08-20 · Journal Article
- In vitro pharmacological characterization of growth hormone secretagogue receptor ligands using the dynamic mass redistribution and calcium mobilization assays.current
Sturaro C, Ruzza C, Ferrari F, Pola P, Argentieri M, Frezza A, Marzola E, Bettegazzi B, Cattaneo S, Pietra C, Malfacini D, Calò G
European journal of pharmacology · 2024-08-10 · Journal Article
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Methodology & citation verification
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