MOTS-c | 40mg | 3ml

MOTS-c is a 16-amino-acid mitochondrial-derived peptide (MDP), encoded by a short open reading frame sitting inside the 12S rRNA region of mitochondrial DNA rather than in the nuclear genome — the structural fact that defines the MDP class and separates it from the nuclear-encoded peptides that make up most of a research catalog. What is supplied here is the synthetic sequence, not material isolated from tissue.

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Reading the sequence like an analyst

The sequence is MRWQEMGYIFYPRKLR, giving an average mass near 2,175 Da for the unmodified peptide. Four features of that string determine most of what a receiving laboratory will see on its own instruments:

• Two methionines, at positions 1 and 6. Methionine sulfoxide formation is a known degradation route for a sequence carrying two of them. It shows on mass spectrometry as a +16 Da satellite and on reversed-phase HPLC as an earlier-eluting shoulder. If you run one incoming check, run that one.
• A tryptophan at position 3, plus tyrosines at 8 and 11. These give a real 280 nm chromophore, so UV quantitation is meaningful rather than an approximation. Tryptophan is also photosensitive, which is why amber glass and dark storage are functional requirements, not packaging aesthetics.
• No cysteine anywhere in the chain. There is no disulfide to scramble and no free thiol to dimerize, which removes an entire failure class that complicates many other research peptides.
• Three arginines and a lysine against a single glutamate. Net charge is strongly basic, so the peptide behaves predictably under ion-pairing reversed-phase conditions and lends itself to cation-exchange as an orthogonal identity check. The glutamine at position 4 carries the ordinary deamidation risk — a +1 Da shift that low-resolution instruments miss.

Because MOTS-c is encoded mitochondrially, the published literature around it sits mostly in the study of mitochondrial-to-nuclear ("retrograde") signalling and cellular energy-sensing pathways. Those are fields of inquiry, not descriptions of what this material does. The work in them is a body of in-vitro and animal laboratory research under examination, and nothing on this page should be read as drawing conclusions from it.

Why a number on the label is not one number

A vial marked 40mg is describing peptide mass — but synthetic peptides do not arrive as pure peptide by weight. A basic sequence like this one is commonly isolated as a salt, and the counter-ion occupies real mass. So does bound water, which lyophilized material picks up readily. For a peptide carrying four basic residues, the combined counter-ion and moisture fraction is not trivial.

That produces the mismatch worth catching first: gross peptide weight versus net peptide content. Ask any supplier, ours included, which figure their label states, and by what method the net figure was established — amino acid analysis and quantitative nitrogen determination are defensible; back-calculating from an HPLC area percentage is not. Purity and content are separate questions, and a certificate that answers only the first has answered half.

Two formats, two failure modes

Research peptides reach a bench in one of two states: as a lyophilized solid, or as a solution filled and sealed upstream. Neither is universally correct, and the useful way to think about them is that they fail differently rather than that one is standard. Confirm which state a given lot ships in — from any supplier, ours included — before you plan the receiving work, because the checks below are not interchangeable.

Where material arrives already in solution, the weighing arithmetic moves off your bench and onto the supplier's fill process. That is a genuine convenience and a genuine transfer of trust, which is the honest way to frame the trade-off. If your workflow depends on preparing your own buffer systems or solvent matrices, a solid is the more flexible starting point. If your variance problem is operator-to-operator preparation across a multi-month protocol, a single upstream fill is the tighter control.

What a certificate of analysis should contain

Two further tests of a document's seriousness: it should name the laboratory that ran the analysis, and the batch number on the paperwork should match the vial in your hand. A certificate that cannot be tied to a specific lot is a marketing asset, not a quality record. The certificate for MOTS-c is published with the rest of ours at /coa.

Storage, handling and origin

Treat this as a light-, oxygen- and cycle-sensitive material, and match the handling to the state your lot actually arrives in. If it arrives in solution, aliquot on arrival into single-use volumes rather than repeatedly opening one container, and minimize headspace. If it arrives as a solid, keep it sealed and dry until you prepare it, then treat the prepared material the same way. Either way, keep it dark and cold and record the date the container was first opened. Methionine oxidation is cumulative and silent — it is not visible on inspection.

This material is synthesized in the UK and verified in US laboratories. That split is deliberate: synthesis and analytical verification are separate disciplines, and having the second performed independently of the first is worth more than either being carried out under one roof.

Availability

MOTS-c is currently out of stock. Batches are not held continuously, and each new lot is analyzed before release rather than being drawn from a standing pool, so restock timing follows the analysis rather than the order book. Its certificate of analysis stays published at /coa either way, and the rest of the catalog is at /shop.