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MOTS-c and Mitochondrial Peptide Research: A Chemistry Primer

MOTS-c is a 16-amino-acid mitochondrially-derived peptide with unusual chemistry. A primer on sequence, synthesis, and how it is characterized for research use.

MOTS-c is an unusual peptide — encoded within a mitochondrial rRNA sequence rather than a nuclear gene. For research chemists, that origin shapes how the reference standard is characterized.

Origin and Sequence

MOTS-c is a 16-amino-acid peptide encoded within the 12S rRNA region of human mitochondrial DNA (specifically, the mt-RNR1 gene). Its sequence:

Met-Arg-Trp-Gln-Glu-Met-Gly-Tyr-Ile-Phe-Tyr-Pro-Arg-Lys-Leu-Arg

Molecular formula C106H159N33O23S2, average molecular weight 2173.54 g/mol, CAS 1627580-64-6.

The presence of two methionines and one tryptophan makes this sequence oxidation-sensitive during synthesis and storage.

Synthesis and Its Complications

Research-grade MOTS-c is produced via Fmoc SPPS. Three manufacturing care points:

  • Met oxidation. Both methionines are prone to sulfoxide formation. The final cleavage cocktail must include thioanisole scavenger, and the post-cleavage handling must minimize air exposure.
  • Trp protection. The tryptophan must be protected (Boc on the indole N) to prevent alkylation during TFA cleavage.
  • Multiple arginines. Three Arg residues mean side-chain Pbf protection across 12+ hour cleavage steps — extended scavenger cocktail is essential.

How a Reference Standard Is Verified

Beyond the standard HPLC + MS + endotoxin + moisture quartet, a MOTS-c release spec should disclose:

  • Met sulfoxide content (typically < 2% of main peak by HPLC integration).
  • Trp integrity confirmed by ESI-MS isotope pattern.
  • Residual scavenger (thioanisole) below detection.

BioFusion’s MOTS-c release protocol includes all three in the per-lot COA.

Storage

Lyophilized MOTS-c: −20 °C long-term, in nitrogen-purged or vacuum-sealed container, protected from light. Reconstituted MOTS-c: 2–8 °C in dark conditions, use within 7 days. Oxidation is the primary degradation pathway.

Related Mitochondrial Peptides in the Catalog

These four form the Mitochondrial Compounds class archive at /peptide-class/mitochondrial-compounds/.

Related Reading

Laboratory research use only. Not for human or veterinary consumption.