Frog-skin opioid peptide (Deltorphin 1)
A natural pain-signaling peptide first found in frog skin that switches on the body's built-in opioid 'painkiller' receptors; used only as a lab research tool, not a medicine.
- Class
- Frog-skin opioid peptide (amphibian delta-opioid family)
- Status
- No approved therapeutic status identified
- Best-supported effect
- Antiproliferative activity against murine CD4+ and CD8+ T cells in a single published class-level cell assay (in vitro)
- Main caveat
- Evidence is limited to one class-level in vitro study; no animal or human data are attached to this card
A researcher, an agent, or an algorithm wrote down the sequence and picked a target to hit.
An AI model like OpenFold3 or AlphaFold built a 3D structure and scored how well it fits the binding site.
A second contributor repeated the computation on their own hardware and the scores matched.
A chemistry service or a researcher ordered the sequence, it was manufactured, and mass spectrometry confirmed the right molecule was produced.
A binding or activity measurement confirmed that it actually does what the computer predicted — or didn't.
Snapshot
Class: Frog-skin opioid peptide (amphibian delta-opioid family)
Evidence tier: In vitro / assay evidence
Status: No approved therapeutic status identified
Best-supported effect: Antiproliferative activity against murine CD4⁺ and CD8⁺ T cells in a single published cell assay (in vitro, delta opioid class)
Main caveat: Evidence is limited to one class-level in vitro study; no animal or human data are identified
What this is
Deltorphin 1 is a heptapeptide originally isolated from the skin of Sauvage's leaf frog (Phyllomedusa sauvagei). It belongs to the deltorphin family of amphibian skin peptides, which are recognised as selective ligands for the delta-opioid receptor (DOR). The peptide contains a D-alanine residue at position 2 — an unusual feature among naturally occurring vertebrate peptides — along with a C-terminal amide modification. These structural features are associated, in the broader deltorphin literature, with resistance to enzymatic degradation and enhanced delta-opioid receptor selectivity. No dedicated mechanism, animal, or human efficacy data are individually extracted from the available literature.
Evidence map
| Evidence layer | Grade | What it supports |
|---|---|---|
| Human | None identified | No human data identified |
| Animal | None identified | No animal study data identified |
| In vitro | Weak | One published class-level cell assay reports antiproliferative effects of delta opioids on highly purified murine CD4⁺ and CD8⁺ T cells; deltorphin-1-specific assay conditions are not individually extracted from available literature |
| Computational | None identified | No computational or structural prediction data attached |
| Mechanism | Unknown in this card | Delta-opioid receptor selectivity is attributed to the deltorphin family in available literature descriptor; no receptor binding data, affinity values, or pathway characterisation are individually extracted |
Claim check
| Claim | Verdict | Evidence layer | Confidence |
|---|---|---|---|
| Antiproliferative effects on T cells (delta opioid class, murine in vitro) | Supported (in vitro) | In vitro | Low — single class-level murine cell assay; no in vivo or human replication identified |
| Delta-opioid receptor agonist activity | Weak / not established in this card | In vitro | Low — receptor pharmacology is described for the deltorphin family in source descriptor context; no binding data are individually extracted from available literature |
| Any therapeutic or clinical application | Not established | None | High confidence in absence — no human data of any kind present |
Assay conditions
This section reports the system and endpoint described in available literature-cited assay. It does not establish animal or human exposure.
| Context | System | Assay condition | Timepoint | Endpoint | Limitation |
|---|---|---|---|---|---|
| Cell assay | Highly purified murine CD4⁺ and CD8⁺ T cells | Not individually extracted from available literature | Not individually extracted | Antiproliferative activity | Single published study; murine cell system; assay conditions not individually characterised; no in vivo or human translation established |
Assay limitations
- Assay conditions, concentrations, and exposure timepoints are not individually extracted from the available literature file.
- All evidence derives from a murine T-cell culture system; no whole-organism or human data are attached.
- In vitro antiproliferative activity does not establish in vivo efficacy, systemic tolerability, or therapeutic effect.
- Published research reference is a class-level delta opioid study; whether deltorphin-1 was specifically characterised in that assay is not resolvable from the available literature.
- No safety or toxicology data are present in available literature.
Mechanism
Deltorphin 1 is grouped within the deltorphin family of amphibian skin peptides, which are described in available literature descriptor as selective delta-opioid receptor ligands. The D-Ala residue at position 2 is structurally associated with peptidase resistance and receptor selectivity; the C-terminal amide is a common feature in opioid peptides associated with receptor binding. No receptor binding constants, affinity values, selectivity ratios, or downstream signalling pathway data are individually extracted from the available literature. The mechanism information above is background context drawn from available literature descriptor; it is not independently evidenced within the attached available literature.
Chemistry
| Field | Value |
|---|---|
| Amino-acid chain (shorthand) | YaFDVVG-NH₂ (lowercase 'a' = D-Ala) |
| Full sequence | H-Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH₂ |
| Length | 7 amino acids |
| Topology | Linear |
| Modifications | D-Ala at position 2; C-terminal amide (NH₂) |
| Molecular weight | Not provided in source |
| Formula | Not provided in source |
| CAS | Not provided in source |
| Sequence confidence | Needs review — single catalog source; no cross-source verification performed |
Published research provides two sequence notations that are internally consistent: the shorthand YaFDVVG-NH₂ and the expanded form H-Tyr-D-Ala-Phe-Asp-Val-Val-Gly-NH₂. The D-alanine substitution and C-terminal amide are noted explicitly in available literature.
Open questions
- In vivo translation: Whether the in vitro T-cell antiproliferative effects observed for delta opioids translate to animal or human immune function is not established by any data identified.
- Receptor pharmacology: Binding affinity, selectivity data, and downstream delta-opioid receptor signalling for deltorphin-1 specifically are not individually characterised in available literature material.
- Safety and tolerability: No toxicology, in vivo safety, or adverse-event data of any kind are identified.
- Assay specificity: Whether the Shahabi & Sharp (1995) reference characterised deltorphin-1 individually or tested delta opioids as a class is not resolvable from the available literature.
- Sequence verification: The sequence is drawn from a single catalog source; independent confirmation against primary literature has not been performed for this card.
▸full evidence table2 metrics
| metric | value | tool |
|---|---|---|
| ipTM | 0.9138727188110352 | boltz-2 |
| ranking score | 0.7933521866798401 | boltz-2 |
▸structural qualityopenfold3
| metric | value | note |
|---|---|---|
| gpde | 1.011 | global PDE — lower = better |
| disorder | NaN | fraction disordered |
▸3-letter notation
▸recipeboltz-2 1.0
| parameter | value |
|---|---|
| model | boltz-2 1.0 |
| weights | — |
| hardware | nvidia_nim_api |
| mlx version | — |
| python | — |
| random seed | — |
| msa strategy | none |
| diffusion samples | 1 |
| runtime | — |
| predicted by | mlx@peptide |
| predicted at | 2026-04-24 |
▸citationbibtex
@peptide{pep10693,
sequence = {YDAFDVVG},
target = {oprm1},
author = {peptidemodel},
year = {2026},
status = {synthesized}
}