Compound monograph
Oxytocin
Oxytocin is a mature nine-residue peptide with an intramolecular disulfide and a terminal carboxamide. This identity record is scoped to the Leu8 form.
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Identity & nomenclature
Oxytocin is a mature nine-residue peptide with an intramolecular disulfide and a terminal carboxamide. This identity record is scoped to the Leu8 form.
OXT and OT are ambiguous abbreviations and are not retained as aliases. The name does not establish the identity of every species variant or commercial preparation. PubChem CID 439302 and GSRS UNII 1JQS135EYN, which lists CAS 50-56-6, specify Gln4, Leu8, Cys1–Cys6 disulfide and Gly9-amide; these remain registry candidates while this record’s sequence and stereochemical admission are unresolved.
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Molecular properties
| Terminal groups | Free N-terminus; C-terminal amidation at Gly9 |
|---|
Numbering begins at the mature N-terminal residue. The complete sequence is withheld because the source descriptions disagree at residue 4; complete stereochemical admission also remains unresolved.
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Structural characteristics
The disulfide links mature positions 1 and 6, and the C-terminal glycine is amidated. Layden et al. (PMID 37649440) describe oxytocin as a cyclic peptide with a disulfide bond between Cys1 and Cys6. The Gln4 versus glutamyl4 source disagreement leaves the complete sequence, molecular formula and average molecular mass unresolved; those fields are withheld.
- Cys1-Cys6 intramolecular disulfide
Ring closures: covalent bonds between residues, by position counted from the first residue of the chain.
- Disulfide Cys1–Cys6: thiol sulfur (Sγ) to thiol sulfur (Sγ). Source: PMID 37649440.
Terminal features: Free N-terminus, C-terminal amidation at Gly9.
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Molecular targets & mechanisms
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Analytical considerations
The mature amide, glycine-extended forms and counterion-containing preparations are distinct molecular states. Elemental composition alone does not establish sequence order or complete stereochemistry.
Disagreements and mix-ups
Points where sources disagree about this compound's identity, or where a name or form is easily confused with another, as noted in this record. The discrepancy register quotes the passage for each one.
Sources disagree · unresolved · Sequence
Residue 4: glutamine or glutamate
What the studies reported
Each finding describes one cited study in its stated model. These observations are specific to that study and do not establish effects in other settings.
Cell and tissue studies
HEK293T cells expressing oxytocin receptor and chimeric Gαs/Gαq (sq5)
Layden et al. reported an EC50 of 0.97 nM for native oxytocin in a GloSensor cAMP assay using HEK293T cells expressing oxytocin receptor and a chimeric Gαs/Gαq protein.
Reference [2]Hippocampal CA1/CA2 parvalbumin-expressing interneurons in acute PvalbCre/Rosa26-lsl-tdTomato mouse brain slices
Layden et al. recorded an inward current within 3–4 minutes of native oxytocin bath application in parvalbumin-expressing CA1/CA2 interneurons in acute hippocampal slices from PvalbCre/Rosa26-lsl-tdTomato mice (seven cells from four mice).
Reference [2]
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Verified bibliography
Cited studies by type
The 2 papers this record cites, counted by the kind of work each reports. A count is the size of this record's selection, not of the research that exists, and says nothing about results, safety, effectiveness or approval.
A paper can report more than one kind of work. Each count opens those papers in the bibliography. Compare every record on the Evidence Map.
Reference 1
Oxytocin solution structure changes upon protonation of the N-terminus in dimethyl sulfoxide.Kato T, Endo S, Fujiwara T, Nagayama K
Journal of biomolecular NMR · 1993-11 · Journal Article
currentReference 2
A Biomimetic C-Terminal Extension Strategy for Photocaging Amidated Neuropeptides.Layden AE, Ma X, Johnson CA, He XJ, Buczynski SA, Banghart MR
Journal of the American Chemical Society · 2023-08-31 · Journal Article
current
Study models of these references
What kind of experiment each cited paper reports, taken from its abstract unless marked. Not a summary of results.
| Reference | Study models |
|---|---|
| Kato T et al. 1993 | Chemical, structural or analytical study; no biological model reported |
| Layden AE et al. 2023 | Study models reported: in vitro · from the abstract |
Record history
Published 2026-09-28.
- : Identity and nomenclature
- : Sequence and structure, References
Each entry names the parts of this record that changed on that date. Changes to links between records and to catalogue links are not listed. This history covers the tracked record fields; study findings are not listed here.
Cite this record: Purely Peptides Research Library. Oxytocin. Published 2026-09-28; updated 2026-10-13. https://purelypeptides.org/research/compounds/oxytocin/
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Methodology & citation verification
Reference identity is checked against official PubMed metadata. Local deterministic receipts bind each normalized title and canonical metadata record to its verification date. Scientific values remain absent when an authoritative source has not been verified.
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