AOD-9604 peptide: sequence, molecular data, certificate of analysis, 5 mg vial

AOD-9604 is a laboratory code from Monash University in Melbourne, given in the 1990s to a synthetic fragment of the growth hormone molecule.

The name is not chemical: "AOD" is a project acronym and 9604 a compound number, in the same way that SS-31 is a position in the Szeto-Schiller series.

What the code designates is precise, though: the last fifteen residues of hGH (somatotropin), positions 177 to 191, with one tyrosine added at the N-terminus. Sixteen residues in all.

The added tyrosine is a chemist's handle.

The native 177-191 stretch carries a single aromatic residue (the C-terminal phenylalanine); a tyrosine in front gives the fragment a second one, which can be iodinated for labeling and which absorbs at 280 nm.

It is also the first thing to look for on a data sheet: a "177-191 fragment" of fifteen residues, without the tyrosine, is a different peptide with a different mass, 1,652 instead of 1,815.

The molecule is a fragment, not the hormone. hGH is a 191-residue protein of 22,124 g/mol with two disulfide bridges; AOD-9604 is 8 % of that chain and carries one of the two bridges.

Nothing on this page concerns the protein it was cut from. Research use only. Not for human or veterinary use.

The chain has two arginines (positions 3 and 8) and a glutamic acid at 11, so the peptide is basic overall and is purified and supplied as an acetate salt, like most of the catalog.

It has two cysteines (positions 7 and 14) joined by a disulfide, which is the feature that decides how a certificate is read, below.

The added tyrosine gives it a signal at 280 nm alongside the 214 nm peptide-bond signal (the C-terminal phenylalanine absorbs weakly, and lower, near 257 nm).

Two other catalog peptides are also fragments of larger proteins, cut from a different molecule: sermorelin is residues 1 to 29 of GHRH, and thymosin alpha-1 is a 28-residue thymic peptide.

Sharing the word "fragment" is all they have in common with AOD-9604.

A linear peptide is finished when the last residue is coupled.

A peptide with two cysteines is not: after cleavage from the resin, the two thiols must be oxidized to a disulfide, in dilute solution so that the bridge forms inside each molecule rather than between two of them.

This step is where a lot of AOD-9604 either becomes the compound on the label or does not.

Three species can come out of it, and mass spectrometry tells them apart.

• The bridged monomer, 1,815.1 g/mol: the product. Seen as the doubly charged ion near m/z 907.9 [M+2H]²⁺ and the triply charged ion near 605.6 [M+3H]³⁺, both reconstructing to 1,813.9 monoisotopic.
• The reduced dithiol, two daltons heavier (1,817.1): the bridge never formed. It elutes slightly later on reverse-phase HPLC and shows as 908.9 and 606.3. A certificate whose mass reconstructs to 1,817 describes an unfinished peptide.
• Intermolecular dimers, near 3,630: two chains cross-linked instead of one chain closed on itself. They elute well after the main peak and belong to the impurity total.

A certificate that gives the mass to the dalton, with the charge states it was read from, answers the question. A certificate that prints "MW 1815" with no measured spectrum has not looked.

Four lines carry the document for a sixteen-residue bridged peptide.

• Purity by reverse-phase HPLC. One main peak, its area against total peak area, read at 214 nm and confirmed at 280 nm thanks to the tyrosine and phenylalanine. Above 98 % is the figure for a catalog lot. The by-products to expect are the reduced form and the dimers described above, and the deletion sequences of a sixteen-residue synthesis (a missing glycine at 57 daltons lower, a missing serine at 87 lower).
• Mass by mass spectrometry. Reconstructed mass near 1,813.9 (monoisotopic) or 1,815.1 (average), from the +2 and +3 ions. This line is where the bridge is proven.
• Net peptide content, by amino-acid analysis or nitrogen determination. With three basic sites, the acetate salt of a 1,815-dalton peptide carries up to 180 g of acetate per mole, so a pure lyophilized lot cannot exceed 91 % net content, and 80 to 88 % after residual water is the realistic band. A 5 mg fill therefore holds roughly 4 to 4.4 mg of peptide; the arithmetic is set out on the bacteriostatic water calculator.
• Lot number, date, laboratory name, and a photograph of the labeled vial. The four fields that tie the document to the object received.

How to read each field, and how to check a report number against the laboratory itself, is in how to read a peptide COA and how to read a Janoshik test report. Certificates are published per lot in the COA library.

AOD-9604 is listed in one size, a 5 mg vial: 5 mg of a 1,815-dalton peptide is 2.8 micromoles, the bench quantity for a sixteen-residue compound with a bridge, whose synthesis and oxidation step make the milligram dearer than that of a short linear peptide.

The catalog card at the top of this page reads the live figures from the catalog, so it never contradicts the product page.

AOD-9604 is stocked in occasional certified lots rather than continuously: between lots the AOD-9604 product page shows the size as temporarily unavailable, and a line to support@oxpeptides.com is answered with the date of the next lot.

No price is promised here for that reason; the product page carries the live figure. The neighbouring references in the catalog are ipamorelin, sermorelin and MOTS‑c.

What the price includes at OXpeptides: a sealed, labeled vial from a tested lot, its batch COA, and a replacement if the parcel arrives lost or damaged.

Ships from France (EU) and California (US) · tracked, tracked: $19, free from $150.

See AOD-9604 in the catalog →

• Temperature: −20 °C for long-term storage; 2 to 8 °C for periods of a few weeks.
• Light and moisture: keep the vial sealed and in its box. Let a cold vial reach room temperature before it leaves its bag, so no condensation forms on the glass and none of it reaches the powder.
• Shelf life: 24 months for a sealed lyophilized vial stored as above; the date printed on the label governs.
• In solution: refrigerated, protected from light, and split into aliquots at the moment it is made. The disulfide is stable in solution at neutral pH; what is not is the peptide bond of a sixteen-residue chain thawed twice.

Ambient shipping over a few days does not degrade a sealed lyophilized powder, which is why research peptides travel without cold packs. Compound by compound, the rules are in lyophilized peptides: storage and shelf life.

"AOD-9604 peptide" returns twenty thousand searches a month in the US, and the first page is a mix of encyclopaedia entries, journal abstracts and research suppliers.

The listing worth reading answers five questions on the page itself.

1. Is the sequence printed, with sixteen residues? Tyr-Leu-Arg-Ile-Val-Gln-Cys-Arg-Ser-Val-Glu-Gly-Ser-Cys-Gly-Phe. A page describing "hGH fragment 176-191" (a phenylalanine, not a tyrosine, in front: sixteen daltons lighter) or a fifteen-residue chain is describing another molecule.
2. Is the mass 1,815, and is it measured? A reconstructed 1,817 is the unbridged peptide; a page that gives no measured spectrum has nothing to check.
3. Is there a batch certificate from a named independent laboratory, with a lot number matching the vial, a date, and a photograph of the labeled vial?
4. Is the vial sealed, labeled and lyophilized, with a stated size? A listing that sells a solution has made a choice about storage on the buyer's behalf.
5. Does the page describe the reagent only (sequence, mass, purity documentation, storage), with research use only stated plainly? A supplier who publishes usage content is a supplier easy to shut down, and the parcel in transit belongs to the buyer.

The seven-point method, including what a re-used or edited certificate looks like, is in how to check a peptide supplier. The US-wide checklist is in where to buy research peptides in the US.