Compound record
Oxytocin
Oxt; α-hypophamine; Pitocin
Sequence
CYIQNCPLG-NH2 (disulfide Cys1–Cys6)
CYIQNCPLG
Length counts residues; formula and mass are the stored free-base values from cited sources; CAS and PubChem identify the substance in public registries. More detail: length & peptide bonds, molecular weight
Structure & modifications
Cyclic tocin ring (20-membered disulfide) plus a tripeptide tail. Classification is cyclic because of the intramolecular disulfide.
Notes
Oxytocin is a hypothalamic nonapeptide released from the posterior pituitary. This record is the circulating hormone — not the oxytocin–neurophysin precursor.
Why the sequence looks the way it does
The mature peptide is closed by a Cys1–Cys6 disulfide (the tocin ring) and finished as glycinamide. Those two covalent features drive receptor recognition and explain the cyclic classification plus the disulfide and amidation tags.
| Field | Value on this record | How to read it |
|---|---|---|
| 1-letter sequence | CYIQNCPLG | Searchable core only |
| Display notation | CYIQNCPLG-NH2 + Cys1–Cys6 | Authoritative for mass/chemistry |
| Length | 9 residues | Not “8 bonds + 1 disulfide” |
| CAS / PubChem | 50-56-6 / 439302 | Free-base peptide identity |
Reading tip: Ile3 and Leu8 distinguish oxytocin from arginine vasopressin (Phe3, Arg8). If those positions do not match, you are looking at a different hormone or analogue.
Historical anchor
Oxytocin was the first peptide hormone both sequenced and chemically synthesized (du Vigneaud, 1953). Salt or hydrate forms in commerce may use related registry numbers — always reconcile formula against the free base stored here.
Primary-source references
- PubChem CID 439302 — oxytocin
- UniProt P01178 (oxytocin-neurophysin 1, Homo sapiens)
- du Vigneaud V. et al. The synthesis of oxytocin. J. Am. Chem. Soc. 1953.