AOD-9604 is a synthetic 16-residue peptide derived from the C-terminal region of human growth hormone. It is one of only two disulfide-containing peptides in this catalogue, which changes both how it should be characterised and how it should be stored.
| CAS Registry Number | 221231-10-3 |
|---|---|
| Molecular formula | C78H123N23O23S2 |
| Average molecular weight | 1815.1 g/mol |
| Sequence | YLRIVQCRSVEGSCGF (16 residues) |
| Disulfide | Cys7–Cys14, intramolecular |
| Class | hGH C-terminal fragment analogue |
| Physical form | Lyophilised powder, sealed glass vial |
| Storage | 2–8 °C, sealed and dry, protected from light |
| Catalogue reference | CA-10 |
The naming problem: AOD-9604 is not hGH fragment 176-191
Many catalogues list “AOD-9604” and “hGH fragment 176-191” as synonyms. Strictly they are different molecules.
The native growth hormone sequence at residues 177–191 begins with phenylalanine. AOD-9604 carries an additional N-terminal tyrosine in place of that native residue arrangement, giving a 16-residue peptide beginning YLRIVQ… The added tyrosine is a deliberate synthetic modification, not a transcription of the native fragment.
The practical consequence: a certificate headed “hGH fragment 176-191” may describe either molecule, and their masses differ. Check the sequence on the certificate rather than relying on the name.
A related error worth knowing: ChemicalBook’s record miscounts the peptide as 15 residues. It is 16.
Identity and classification
No receptor or molecular target is assigned to AOD-9604 in reference-supplier catalogue classification, and we make no claim about one. It is supplied and characterised as a sequence-defined synthetic peptide with a defined disulfide.
Structure
Sixteen standard L-residues, free C-terminal acid, with an intramolecular disulfide bond between Cys7 and Cys14 closing a loop of six residues. The two sulfur atoms in the molecular formula are those two cysteines — there is no methionine.
The disulfide is the defining structural feature. It is what makes the molecule a constrained loop rather than a linear chain, and it is the feature most likely to be wrong in a poorly made lot.
Specification and characterisation — the disulfide is the whole story
For a peptide with a defined disulfide, mass and purity alone are inadequate, because the most important failure modes are mass-neutral:
- Non-reduced versus reduced HPLC. The essential test. Chromatograph the material as supplied, then again after reduction with DTT or TCEP. The retention shift confirms a disulfide is present. A single non-reduced chromatogram does not.
- Free thiol determination. Ellman’s reagent (DTNB) quantifies unreacted cysteine. A material with significant free thiol has incompletely formed disulfide — the linear dithiol form, which is +2 Da and easily missed.
- Disulfide scrambling and dimers. With only two cysteines there is a single correct intramolecular pairing, but intermolecular pairing produces dimers and higher oligomers. These are mass-resolvable and appear as later-eluting or size-shifted species. Size-exclusion chromatography catches them.
- Mass confirmation against 1815.1. Note the oxidised (correctly folded) form is 2 Da lighter than the reduced form — that 2 Da is the diagnostic.
- RP-HPLC purity at 214 nm, with 280 nm informative via the tyrosine and phenylalanine.
- Counter-ion and net peptide content. Commonly supplied as the acetate.
A certificate for a disulfide peptide that reports only area percent and a nominal mass has not characterised the feature that defines the molecule.
Handling and stability
Store sealed at 2–8 °C, dry, protected from light. Equilibrate in a desiccator before opening.
Disulfide-containing peptides are subject to oxidation and disulfide scrambling, and both are accelerated by moisture, by alkaline pH and by dissolved oxygen. Where solutions are prepared, degassing or purging with an inert gas is a meaningful precaution rather than a formality, and neutral-to-slightly-acidic buffers are preferable — thiol–disulfide exchange accelerates sharply above pH 7.
Related compounds in this library
Glutathione is the other sulfur-redox-active compound here, though it is the reduced thiol rather than a formed disulfide, and its oxidised counterpart GSSG is an intermolecular dimer rather than an intramolecular loop. The two entries together cover both sides of thiol–disulfide chemistry.
References
Chemical, specification and analytical sources. This list is deliberately limited to chemistry and analytical references.
- Cayman Chemical, AOD-9604 record — formula, molecular weight, sequence, disulfide assignment
- Chemsrc, CAS 221231-10-3 — registry and mass data
- ChemicalBook, AOD-9604 record — registry confirmation (note: this source miscounts the peptide length as 15 residues)
- Bachem, Handling and Storage Guidelines for Peptides — cysteine oxidation, disulfide handling, degassed buffers
Available from the catalogue
AOD-9604 5 mg — 5 mg of lyophilised powder in a sealed glass vial, supplied with a lot-matched certificate of analysis. Bulk pricing applies from five vials.
Cosmic Aminos supplies this material as a laboratory reagent for in-vitro research use only. It is not a drug, food, cosmetic or dietary supplement, is not approved by the Food and Drug Administration for any use, and is not for human or veterinary consumption. No dosing, administration or preparation guidance is provided.