MOTS-c in Canada: The Mitochondrial-Encoded Peptide, Explained

Labs sourcing MOTS-c in Canada are usually buying it for a specific reason: it is one of the few peptides whose coding sequence lives in the mitochondrial genome rather than the nucleus. That origin story is what makes it interesting to researchers, but it has no bearing on how the synthetic material behaves on a bench. For the people who order, receive and check it, the chemistry of the sixteen residues matters more. This guide covers both: where the peptide comes from, and what its sequence means for testing, storage and record keeping across a multi-vial order.

A peptide written in mitochondrial DNA

Human mitochondria carry their own small circular genome. It encodes two ribosomal RNAs, a set of transfer RNAs and thirteen protein subunits of the respiratory chain. Everything else the organelle needs, which is the great majority of its proteins, is encoded in the nucleus and imported.

MOTS-c breaks that pattern. Its name stands for mitochondrial open reading frame of the 12S rRNA type-c, and it describes exactly where the sequence was found: a short open reading frame tucked inside the gene for the 12S ribosomal RNA. It was first described in the published literature in 2015. In that original work, the peptide was linked to metabolic signalling in cultured cells, including the AMPK pathway, which is why it is studied mainly in cell-based metabolic research.

Where MOTS-c sits among mitochondrial-derived peptides

MOTS-c is not the only peptide traced to the mitochondrial genome. Researchers group it with a small family usually called mitochondrial-derived peptides:

• Humanin, the first to be reported, encoded within the 16S rRNA gene.
• Small humanin-like peptides, a numbered series also found in the 16S rRNA region.
• MOTS-c, the member located in the 12S rRNA gene.

It is worth separating all of these from peptides that are simply aimed at mitochondria. SS-31, for example, is a synthetic tetrapeptide with no natural gene at all. It associates with cardiolipin in the inner mitochondrial membrane because of how it was designed, not because of where it came from. “Mitochondrial” means origin for one and destination for the other.

MOTS-c sequence and specifications

The peptide is a linear chain of sixteen amino acids. The figures below are the ones a certificate should agree with.

The name also turns up as MOTS-C and MOTSc on labels and in papers. All three refer to the same molecule, and the sequence is the reliable way to confirm it.

How the sequence shows up in testing

Three features of this particular chain shape what you see on an analytical report.

Two methionines, two oxidation steps

Methionine’s thioether side chain is easily oxidised to the sulfoxide, adding one oxygen atom, or 16 Da. MOTS-c has two of them, so oxidation can happen once or twice. On a mass spectrum, look for companions near 2190.6 (one oxidation) and 2206.6 (two). These are genuine degradation products, not the labelled compound, but their presence does not by itself mean the synthesis was poor. Oxidation can build up after testing, which is why a certificate describes the lot on its test date.

Strong UV response

With one tryptophan, two tyrosines and a phenylalanine, MOTS-c gives a strong signal at 280 nm, in addition to the peptide-bond absorbance near 214 nm that every peptide shows. Purity measured at either wavelength is meaningful here, which is not true for sequences with no aromatic residues. The report should still state which wavelength was used.

A basic, partly hydrophobic chain

Four positively charged residues give MOTS-c a strong tendency to interact with residual silanol groups on some reversed-phase columns, which can cause tailing. A tailing peak makes integration sensitive to where the baseline is drawn. That is one ordinary reason two labs can report slightly different purity for material from the same vial, as discussed in why certificates of analysis disagree.

Storing MOTS-c across a large order

Because oxidation is the main degradation route to watch, the handling rules for a multi-vial lot follow from limiting oxygen, light and moisture:

• Keep unopened vials cold, dry and dark, and log the date each group went into storage.
• Let a vial reach room temperature before opening it, so condensation does not form on the powder.
• Open only what an analytical run needs; untouched vials in the same lot stay in their original condition.
• For analytical solutions, use fresh, peroxide-free solvents, since aged ethers and some surfactants carry oxidants.
• If a stored lot is re-tested months later, compare the +16 and +32 peaks with the original certificate before drawing conclusions.

Our article on how peptides degrade covers the chemistry behind each of these steps.

Ordering MOTS-c in Canada for a research programme

We stock MOTS-c in 10mg and 20mg lyophilised vials, shipped from within Canada. For a study that will draw on the same material for months, the practical choices are about lots and records:

1. Order enough vials from one lot to cover the planned work, so results are not split across lots.
2. On arrival, match each vial’s cap and crimp colour to its certificate and record the pairing in your inventory.
3. Check the certificate’s measured mass against 2174.6 and note any oxidised species it reports.
4. Keep net peptide content in mind when calculating concentrations; the net peptide content guide explains the difference from gross weight.

Volume pricing is mix-and-match, so MOTS-c vials count toward the same break as SS-31 or any other compound in the cart. Products are third-party tested for purity by HPLC, and certificates are published for some products on our certificates of analysis page. For more on the research literature around both mitochondrial peptides, see mitochondrial peptides in research.

MOTS-c from Bulk Peptides is sold for in-vitro laboratory research only. It is not a drug or supplement, is not for human or animal use, and this article offers no guidance on any such use.