Compound record
Carbetocin
1-deamino-1-monocarba-2-O-methyltyrosine-oxytocin; [deamino-carba1, Tyr(Me)2]oxytocin
Sequence
Butyryl-Tyr(Me)-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH2 (carba-1 thioether to Cys6)
YIQNCPLG
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 via a thioether, not a disulfide. Length counts amino-acid residues in the peptide chain excluding the butyryl cap as a residue.
Notes
Carbetocin is a long-acting oxytocin analogue: the Cys1–Cys6 disulfide is replaced by a carba/thioether bridge, and Tyr2 is O-methylated. Glycinamide is retained.
| Feature | Oxytocin | Carbetocin |
|---|---|---|
| Ring closure | Disulfide | Thioether / carba |
| Tyr2 | Phenol | O-methyl |
| C-terminus | Gly-NH2 | Gly-NH2 |
| CAS | 50-56-6 | 37025-55-1 |
Still classified cyclic, but not via a cystine — do not apply a “−2.016 Da per disulfide” correction as you would for oxytocin. PubChem CID 16645.
Primary-source references
- PubChem CID 16645 — carbetocin
- CAS 37025-55-1
- Barth T. et al. Biological activities and metabolic stability of carba analogues of oxytocin. Collect. Czech. Chem. Commun. 1973.