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Molecular Weight
Purity
Storage
Appearance
Solubility
01
Oxytocin is a nine-residue neuropeptide hormone, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂, with a disulfide bond between Cys1 and Cys6 that closes a six-residue ring. It is produced in the hypothalamus and released from the posterior pituitary, and acts mainly through the oxytocin receptor, a G protein-coupled receptor.
Oxytocin is one of the most studied neuropeptides, with research spanning social behaviour, reproduction and neuroendocrine signalling. Synthetic oxytocin is also an approved medicine, but the material listed here is supplied solely as a lyophilized reference compound for in vitro and analytical research.
02
Oxytocin has a compact cyclic structure with a short tail.
Disulfide ring (Cys1–Cys6)
The bond between Cys1 and Cys6 closes a ring containing Tyr2, Ile3, Gln4 and Asn5. This ring is essential for receptor activity.
C-terminal tail
Pro7-Leu8-Gly9-NH₂ extends from the ring and ends in an amide.
Relation to vasopressin
Oxytocin differs from arginine vasopressin at only two positions (3 and 8), which is why the two peptides show some cross-activity at each other’s receptors.
Sensitive residues
The disulfide, Gln4 and Asn5 (deamidation) and Tyr2 are the main chemical weak points.
03
Oxytocin signalling is well characterised in vitro.
Oxytocin receptor
The oxytocin receptor couples mainly to Gq, triggering phospholipase C, IP₃ and intracellular calcium release, which are standard readouts in receptor-expressing cells.
Cross-reactivity
Oxytocin also activates vasopressin receptors at higher concentrations, so selectivity studies typically include vasopressin and selective antagonists.
Research areas
Published research covers uterine and mammary smooth muscle signalling, social and behavioural neuroscience, and neuroendocrine regulation.
These findings are cited as research context only; no effects are claimed for this material.
04
Receptor pharmacology
A reference agonist in oxytocin and vasopressin receptor binding and calcium-signalling assays.
Disulfide peptide analytics
A classic model compound for analysing cyclic disulfide peptides and their degradation products.
Stability studies
Widely used to study disulfide exchange, deamidation and dimerisation under stress.
Analytical reference
A well-characterised peptide for HPLC and LC-MS method qualification.
05
Storage
Store the lyophilized powder at −20 °C, sealed, desiccated and protected from light.
pH
Oxytocin in solution is generally most stable at mildly acidic pH (around 4–5). Neutral to basic pH promotes deamidation and disulfide exchange.
Disulfide integrity
Avoid reducing agents and thiols, which open the ring. Disulfide exchange can also form dimers and trisulfide variants.
Reconstitution
Soluble in water and dilute acetic acid. Use solutions promptly or freeze single-use aliquots.
Labware
Use low-binding polypropylene tubes and tips.
06
Analysis must confirm the ring and monitor its common degradation products.
HPLC
Reversed-phase C18 with a TFA gradient. Detect at 214 nm, or at 275–280 nm for the tyrosine.
Mass spectrometry
Positive-mode ESI shows [M+H]⁺ at m/z 1007.4 and [M+2H]²⁺ at m/z 504.2 (monoisotopic). The reduced, open form is about 2 Da heavier.
Disulfide confirmation
Comparing reduced and non-reduced samples, or reducing and alkylating the cysteines, confirms the Cys1–Cys6 bond.
Impurity profile
Typical checks include deamidated forms (Gln4, Asn5, Gly9-NH₂ to the free acid), dimers, trisulfide variants, the reduced form and truncated sequences.
07
A nine-residue peptide, Cys-Tyr-Ile-Gln-Asn-Cys-Pro-Leu-Gly-NH₂, with a disulfide bond between Cys1 and Cys6 forming a six-residue ring and a three-residue amidated tail.
They differ at only two positions (3 and 8), so each can activate the other’s receptors to some extent at higher concentrations.
Mainly the oxytocin receptor, a Gq-coupled GPCR, measured through calcium release or IP₃/IP₁ accumulation in receptor-expressing cells.
Mildly acidic pH, around 4–5, is generally most stable. Neutral to basic conditions increase deamidation and disulfide exchange.
Deamidated forms, dimers and trisulfide variants from disulfide exchange, the reduced open form, and truncated sequences.
No. Although oxytocin is used in approved medicines, the material listed here is supplied strictly as a reference compound for laboratory and analytical research and is not for human or animal use.
Oxytocin Research Reference. (2026). Pure Peptides Labs Research Catalogue. Retrieved from https://purepeptideslabs.net/research-catalogue/neurochemical-research-peptides/oxytocin/
Materials listed on this platform are supported by independent testing and published documentation for laboratory research contexts.
