pe
pep-10559 v1 CC-BY-SA-4.0

Appetite-reducing ghrelin fragment (Des-octanoyl-Ghrelin, mouse/rat)

A natural form of the hunger hormone ghrelin, but without the fatty tail, that reduces food intake and slows gut movement in rodents; used only as a lab research tool.

statusbioassayed targetGHSR length28 aa refs3
EARLY ENTRY This candidate is newly indexed — supporting evidence is still being added. Have a paper or data point? Contribute below.
status 4 / 5 · 2 verified on platform
prediction metrics boltz-2 1.0
ipTM0.825
pTM0.886
avg pLDDT81.4
ranking score0.816
STRUCTURE · PEP-10559 × GHSR
ranking0.816
target interface 4.5Å peptide drag rotate · ctrl+scroll zoom · right-click pan
boltz-2 1.0 · mmCIF ↓ download
sequence28 aa
151015202528
GSSFLSPEHQKAQQ RKESKKPPAKLQPR
in the news 1 article
Hypotheses3 directions▾ collapse

Research directions for this peptide, selected from the current sources — hypotheses you can explore and model. None of it is proven yet; tap any one to see the full thinking.

openupdated 2026-06-11

Could des-octanoyl-ghrelin reduce age-related fat inflammation through a route that is separate from its effect on appetite and weight?

In older adults, losing weight can be harmful, but chronic fat inflammation raises heart and diabetes risk. If this peptide calms fat inflammation independently of weight, it could point to a safer treatment for age-related metabolic disease. This separation of effects is still unproven.

The hypothesis
Des-octanoyl-ghrelin suppresses age-related adipose inflammation and thereby slows progression of metabolic syndrome in aging independently of body weight reduction, positioning it as a therapy for inflammaging rather than solely for obesity.
Why it’s plausible
GHSR regulates adipose inflammation in aging models. Des-octanoyl-ghrelin is appetite-reducing, but anti-inflammatory action in adipose tissue may be mechanistically separable from caloric intake changes. If the peptide directly modulates macrophage polarization or cytokine production in adipose tissue, its benefit for metabolic syndrome would persist even in normocaloric aging subjects.
Why it matters
Separating anti-inflammatory from appetite-suppressing activity would open a therapeutic use case in elderly patients where weight loss is undesirable but adipose inflammation drives cardiovascular and metabolic risk.
Plausibility.60
Novelty.50
Impact.65
Basis · grounding2 papers
[1]
paper
Ghrelin receptor regulates adipose tissue inflammation in aging; anti-inflammatory role documented in aging models separate from acute appetite effects
doi: 10.3390/ijms262210996
[2]
paper
Ghrelin regulates both short- and long-term body weight; distinct mechanisms may underlie appetite vs. inflammatory signaling
doi: 10.1016/j.cell.2008.01.017
openupdated 2026-06-11

Does this peptide suppress appetite by signaling through a different, not-yet-identified receptor instead of the known ghrelin receptor?

The unmodified form of ghrelin is already known to keep working in animals lacking the standard ghrelin receptor, so a separate receptor probably exists. Pinning it down would open a fresh, possibly safer drug target for obesity and metabolic disease.

The hypothesis
The appetite-reducing activity of des-octanoyl-ghrelin is mediated through a GHSR-independent receptor, such as GPR39 or a currently uncharacterized receptor, rather than through competitive inhibition at GHSR1a.
Why it’s plausible
GHSR knockout mice still show some metabolic responses to des-acyl ghrelin, suggesting non-GHSR signaling pathways. The peptide retains a cluster of basic residues (KAQQRK, ESKKPP, KLQPR) that could engage other receptors. High GHSR ipTM may reflect structural mimicry rather than functional antagonism. Identifying an independent receptor would explain appetite reduction without invoking GHSR blockade.
Why it matters
If des-octanoyl-ghrelin signals through a separate receptor, that receptor becomes a new anti-obesity target distinct from GHSR, potentially avoiding the cardiovascular side effects associated with GHSR modulation.
Plausibility.78
Novelty.20
Impact.75
Basis · grounding2 papers · 1 computed/note
[1]
paper
GHSR-null mice model used to interrogate ghrelin/GHSR axis; residual phenotypes in knockouts hint at GHSR-independent effects
doi: 10.1073/pnas.0305930101
[2]
sequenceSequence contains multiple basic-residue clusters (KAQQRKESKKPPAKLQPR) that could engage non-GHSR receptors
[3]
paper
Short- and long-term appetite regulation by ghrelin involves GHSR but also incompletely characterized pathways
doi: 10.1016/j.cell.2008.01.017
openupdated 2026-06-11

Do the positively charged amino acids in the peptide's tail make it bind heparan sulfate on cell surfaces?

If the charged tail binds these surface sugars, it might help concentrate the peptide near tissues, which could be useful for targeting. Whether this favors fat over other tissues is unproven, since these sugars are found on most cells, so any fat-targeting use would need to be demonstrated.

The hypothesis
The basic C-terminal segment (ESKKPPAKLQPR) of des-octanoyl-ghrelin confers adipose-tissue selectivity by engaging heparan sulfate proteoglycans on adipocyte surfaces, concentrating the peptide in fat depots and explaining its preferential anti-inflammatory action in adipose tissue relative to other tissues.
Why it’s plausible
The sequence contains five lysines and two arginines in the C-terminal half, a motif common in heparin-binding peptides. Adipose tissue expresses abundant heparan sulfate. GHSR-mediated adipose inflammation in aging is documented; local peptide accumulation via proteoglycan binding could amplify anti-inflammatory effects without systemic GHSR blockade.
Why it matters
If adipose selectivity is driven by heparin-binding, the peptide's C-terminus could be engineered onto other anti-inflammatory cargo to target fat depots, with implications for metabolic syndrome and obesity-related inflammation.
Plausibility.50
Novelty.60
Impact.55
Basis · grounding1 paper · 1 computed/note
[1]
sequenceC-terminal region ESKKPPAKLQPR has net charge +4 and matches heparin-binding peptide motif criteria (XBBXBX where B=basic)
[2]
paper
Ghrelin receptor regulates adipose tissue inflammation in aging, implicating GHSR-expressing adipose as a relevant tissue compartment
doi: 10.3390/ijms262210996
details expand to inspect
full evidence table2 metrics
metricvaluetool
ipTM 0.8247222900390625 boltz-2
ranking score 0.8161764144897461 boltz-2
structural qualityopenfold3
metricvaluenote
gpde0.647global PDE — lower = better
disorderNaNfraction disordered
3-letter notation
Gly-Ser-Ser-Phe-Leu-Ser-Pro-Glu-His-Gln-Lys-Ala-Gln-Gln-Arg-Lys-Glu-Ser-Lys-Lys-Pro-Pro-Ala-Lys-Leu-Gln-Pro-Arg
recipeboltz-2 1.0
parametervalue
modelboltz-2 1.0
weights
hardwarenvidia_nim_api
mlx version
python
random seed
msa strategynone
diffusion samples1
runtime
predicted bymlx@peptide
predicted at2026-04-24
citationbibtex
peptidemodel (2026). Appetite-reducing ghrelin fragment (Des-octanoyl-Ghrelin, mouse/rat) (pep-10559, v1). PeptideModel. https://peptidemodel.com/card/pep-10559
@peptide{pep10559,
  sequence = {GSSFLSPEHQKAQQRKESKKPPAKLQPR},
  target   = {ghsr},
  author   = {peptidemodel},
  year     = {2026},
  status   = {bioassayed}
}
related peptides 2 by signal overlap
clinical trials 575 on ct.gov · 3 on EUCTR · checked 2026-05-22
ct.gov trials 575
with results 28
EUCTR 3
PubMed RCT 1
by phase
1phase 19no phase
by status
8completed1active1unknown
references 3 papers
discussion no comments
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