Description
PrymaLab · Research Use Only
Adipotide 5mg
Two peptides joined end to end · each doing a different job
Adipotide is not one peptide. It is two, joined end to end into one chain. They were designed by different people for different reasons. One half is an address and the other half is a payload, and a certificate has to account for both.
Specification Table
| Property | Value |
|---|---|
| Compound | Adipotide |
| Common designation | FTPP |
| Article type | Chimeric peptide construct |
| Architecture | A targeting domain joined by a short linker to an effector domain |
| Targeting domain | A cyclic nonapeptide constrained by a disulfide between terminal cysteines |
| Effector domain | A repeated amphipathic sequence built from D-amino acids |
| Why D-amino acids | Protease resistance, and the effector requires only a helical shape rather than a natural configuration |
| Disulfide present | Yes, in the targeting domain. Reduction opens the cycle |
| Reported effector mechanism | Disruption of mitochondrial membrane integrity, triggering apoptosis |
| Reported targeting mechanism | Binding to markers reported on the vasculature of white adipose tissue |
| Origin | Developed from phage display work identifying tissue-selective homing sequences |
| Regulatory status | No approved formulation in any jurisdiction |
| Appearance | White lyophilized powder |
| Purity | Per lot-specific certificate of analysis |
| Storage, lyophilized | 2-8°C short term, -20°C for extended storage, protected from light and moisture |
What Are the Two Halves of Adipotide?
Adipotide has an internal logic that makes it far easier to understand once the two parts are read separately.
The first half is a targeting sequence, a short cyclic peptide whose job is to bind something present on a particular tissue and not on others.
Sequences of that kind come from phage display, a technique that screens enormous libraries of short peptides for ones that concentrate in a chosen tissue.
The output is an address. It carries no activity of its own and it determines where the rest of the molecule ends up.
The second half is an effector, a repeated amphipathic sequence that disrupts membranes and was characterised independently as a proapoptotic domain.
On its own that sequence is indiscriminate, because a membrane-disrupting peptide does not care whose membrane it meets.
Joining the two is the design. The address restricts where the payload arrives, and the payload does something the address cannot.
That is a modular approach rather than a single molecule with a single mechanism, and it explains why the construct is longer and more complicated than anything else in this part of the catalogue.
It also means the two halves can fail independently, which is the point of the next section.
Why Does Each Half Need Its Own Check?
Adipotide has more ways to be wrong than a single sequence does, and one purity figure covers none of them.
The targeting domain is cyclised by a disulfide between cysteines at its two ends, which means it carries the same vulnerability as any disulfide-constrained peptide.
A reduced preparation has an open targeting loop. The mass changes by two daltons. On a construct this size that is a fraction of a percent, effectively invisible at nominal resolution.
An open loop is a different shape, and a targeting sequence that works by shape does not work when the shape is gone.
So a reduced construct still carries a functional payload attached to a targeting domain that no longer targets. That is the worst of the available failure modes.
The effector domain is built from D-amino acids, and configuration cannot be checked by mass because a D-residue and its L-counterpart weigh the same.
A preparation made with the wrong building blocks would pass every mass and chromatographic check and behave differently, since the D-configuration is what gives the domain its protease resistance.
Chiral analysis is the only method that answers it, and it is rarely offered.
The linker between the two is the third point of failure. A construct cleaved at the join is two separate peptides, and the mass of each is well below the intact species.
Chromatography detects that easily, provided anyone looks well ahead of the main peak rather than only beside it.
A fourth failure mode is worth adding because it is specific to constructs carrying both a disulfide and a long chain.
Where more than one molecule is present at concentration, a reduced disulfide can reform between two different molecules rather than within one.
That gives a dimer of twice the mass with an open targeting loop on each half, which chromatography separates readily and a mass check catches immediately if anyone looks above the expected value rather than only below it.
What Does the Published Record Cover?
The literature behind adipotide is small, specific and clearer than for most compounds in this range.
The design was described in the mid 2000s and evaluated in rodent models, with a later study in a non-human primate model.
Endpoints in that work were tissue-level and metabolic measurements over defined periods, reported with the model organism named.
That is a considerably more transparent record than the animal literature behind many compounds here, because the studies state what was measured and in what.
What it does not include is any human evaluation reaching a published controlled trial, and no approved formulation exists anywhere.
The primate study is the closest the record comes to a large-animal result and it is one study, which is a description rather than a criticism.
One finding in that work is worth carrying into any study design, because it concerns the targeting rather than the effector.
Tissue selectivity in the published models was reported as partial rather than absolute, which is the normal outcome for a homing sequence and is often described as though it were complete.
A construct that concentrates in one tissue still reaches others. A membrane-disrupting domain is active wherever it arrives.
Any design using this article should therefore measure what happens in the tissues it was not aimed at, rather than assuming the address did all the work.
What Should the Certificate Show?
An adipotide certificate carries eight fields, more than anything else in this catalogue. That follows from the construct having two halves and a join.
The full sequence written out, with both domains and the linker identified, and the configuration marked at every position.
Observed mass against calculated mass with the instrument resolution stated, since a two dalton disulfide difference on a construct this size needs high resolution.
Explicit confirmation that the targeting-domain disulfide is formed, by mass, by chromatography or by a free thiol assay.
Confirmation of the D-configuration in the effector domain, or at minimum a statement of which protected building blocks were used.
Purity by reverse-phase HPLC with the full chromatogram, viewed across the whole run rather than around the main peak, so that cleaved fragments are visible.
Counterion identity together with net peptide content. A heavily basic effector domain means the trifluoroacetate load on this construct is large.
Lot number and synthesis date.
A certificate that identifies both domains separately is written by a supplier who understands what they made, and it is unusual enough to be a useful signal.
What Does the Linker Do?
The two domains of adipotide are joined by a short stretch of sequence that does no work of its own, and its absence would break the construct.
Fusing two functional peptides directly end to end rarely works, because each one needs freedom to adopt its own shape.
A targeting loop held rigidly against a helical effector is a targeting loop that cannot present its binding face properly.
A short flexible linker separates them, and glycine is the residue used for that because it has the smallest side chain and the greatest backbone freedom.
Two glycines is a common choice and it is enough to decouple the domains without adding length that serves no purpose.
Linker design is a real discipline in construct engineering rather than an afterthought, and the choice involves a trade.
Too short and the domains interfere with each other. Too long and the construct becomes floppy, harder to make, and more exposed to proteases along the connecting stretch.
That last point is the one that matters for handling. A flexible glycine stretch is the least structured part of the molecule and therefore the most accessible to any protease present.
So the linker is where a cleaved construct usually breaks, which is why the chromatogram should be examined for two fragment peaks rather than one degraded main peak.
The masses of those fragments are predictable from the sequence, which makes the check specific rather than a general look for extra peaks.
A supplier who can state the linker composition has told you where the construct is weakest, which is more useful than a purity figure on its own.
How Should the Vial Be Handled?
Handling adipotide combines the requirements of a disulfide-containing peptide with those of a long synthetic chain.
Sealed lyophilized powder holds at 2 to 8 degrees Celsius for short periods and at minus 20 for extended storage, protected from light and moisture.
Bring the vial to ambient temperature before opening, since the powder is hygroscopic and cold glass condenses water onto the cake.
Keep reducing agents away from the preparation and from anything it will meet. Dithiothreitol, beta-mercaptoethanol and tris(2-carboxyethyl)phosphine all open the targeting loop.
That precaution extends to buffers carried over from other procedures and to culture components, which is where it is usually forgotten.
Run the diluent down the wall and swirl gently. The effector domain is amphipathic by design, which is exactly the property that drives a peptide to an air-liquid interface.
That makes this construct more prone to interface aggregation than most, and vigorous handling is a real loss route rather than a theoretical one.
Aliquot on first reconstitution. Freeze-thaw promotes both aggregation and disulfide exchange, and neither is reversible.
Use low-binding consumables, since an amphipathic sequence adsorbs readily to ordinary plastics.
Record lot, net peptide content, whether the diluent contained any reducing species, diluent composition and date.
Published Literature
Selected references on the effector domain, on the targeting approach and on the construct itself.
- Ellerby HM, Arap W, Ellerby LM, Kain R, Andrusiak R, Rio GD, et al. Nature Medicine. 1999;5(9):1032-1038. DOI: 10.1038/12469
- Kolonin MG, Saha PK, Chan L, Pasqualini R, Arap W. Nature Medicine. 2004;10(6):625-632. DOI: 10.1038/nm1048
- Barnhart KF, Christianson DR, Hanley PW, Driessen WH, Bernacky BJ, Baze WB, et al. Science Translational Medicine. 2011;3(108):108ra112. DOI: 10.1126/scitranslmed.3002621
- Javadpour MM, Juban MM, Lo WC, Bishop SM, Alberty JB, Cowell SM, et al. Journal of Medicinal Chemistry. 1996;39(16):3107-3113. DOI: 10.1021/jm9509410
Frequently Asked Questions
What is adipotide?
Adipotide is a chimeric construct rather than a single peptide. A targeting domain is joined by a short linker to a separate effector domain, and the two were designed independently.
What does the targeting domain do?
It binds something reported on a particular tissue and not on others. It carries no activity of its own and determines where the rest of the molecule ends up.
Where did that sequence come from?
Phage display, a technique that screens enormous libraries of short peptides for ones concentrating in a chosen tissue. The output is an address rather than an activity.
What does the effector domain do?
It is a repeated amphipathic sequence that disrupts membranes, characterised independently as a proapoptotic domain. On its own it is indiscriminate.
Why join them?
The address restricts where the payload arrives and the payload does something the address cannot. It is a modular design rather than one molecule with one mechanism.
Why does each half need checking separately?
Because they fail independently. A single purity figure covers neither the disulfide in the targeting domain nor the configuration of the effector domain.
What happens if the disulfide is reduced?
The targeting loop opens. The mass moves by two daltons, which is effectively invisible at nominal resolution, and a sequence that works by shape stops working when the shape is gone.
Why is that the worst failure mode?
Because the construct still carries a functional membrane-disrupting payload attached to a targeting domain that no longer targets.
Why are D-amino acids used in the effector?
For protease resistance. The domain needs a helical shape rather than a natural configuration, so the D-form works and survives longer.
Can mass spectrometry confirm the configuration?
No. A D-residue and its L-counterpart weigh the same, so chiral analysis is the only method that answers it, and it is rarely offered.
How selective is the targeting in published work?
Partial rather than absolute, which is the normal outcome for a homing sequence. A construct that concentrates in one tissue still reaches others.
Why is this one prone to aggregation?
The effector domain is amphipathic by design, which is exactly the property that drives a peptide to an air-liquid interface. Vigorous handling is a real loss route here.
Compliance Statement
Adipotide is sold exclusively for laboratory research use. It is not a drug, food, or cosmetic product, and it is not a dietary product of any kind. It is not approved by the FDA or any comparable authority for human or veterinary use, it is a two-domain construct whose targeting and effector halves fail independently and a single purity figure establishes neither, tissue selectivity in the published models was reported as partial rather than absolute, no human evaluation reaching a published controlled trial exists and no approved formulation exists in any jurisdiction, and no compound in this range is offered for any human or veterinary purpose. This product is not intended to diagnose, treat, cure, or prevent any disease. It must not be given to humans or animals. Purchase is restricted to qualified researchers and institutions operating within applicable laws. All handling is the responsibility of the purchasing laboratory.
Other formats of Adipotide
Adipotide is also stocked as Adipotide (FTPP) 10mg preloaded 3ml pen. Each listing states its own quantity and concentration, and the pen and vial comparison explains what changes between formats. The adipotide sourcing guide covers what to check on a certificate before ordering.
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