What Is MOTS-c? Sequence, Molecular Weight and Origin

MOTS-c is a 16-amino-acid peptide encoded by mitochondrial DNA rather than nuclear DNA. Its sequence is MRWQEMGYIFYPRKLR, its formula C101H152N28O22S2 and its average molecular weight about 2174.6 Da. It was described in 2015 as a mitochondrial-derived peptide that, in mouse studies, influenced metabolic homeostasis [1].

What does the name mean?

MOTS-c stands for mitochondrial open reading frame of the 12S rRNA type-c. The peptide is encoded by a short open reading frame that lies inside the gene for the 12S ribosomal RNA of mitochondria, MT-RNR1. It belongs to a small group of mitochondrial-derived peptides that also includes humanin.

What did the original study report?

The 2015 study identified the peptide, showed that it was present in tissues and plasma, and reported that in mice it affected skeletal muscle metabolism and protected against diet-induced weight gain and insulin resistance [1]. These are findings in cells and animals. Later work has extended the animal and cell literature; it does not establish any use in humans.

What does its structure mean for testing?

Two features of the sequence matter for analysis. First, it contains two methionines, at positions 1 and 6. Methionine oxidizes to methionine sulfoxide, which adds 16 Da, so a mass spectrum of an aged or poorly stored sample may show peaks at about 2190.6 Da and 2206.6 Da alongside the main mass. Second, it contains four basic residues, so it carries several positive charges and appears in electrospray mass spectra as a series of multiply charged ions that must be deconvoluted to the parent mass.

How should MOTS-c be stored?

Because of the methionines, MOTS-c benefits from storage as a sealed lyophilized solid, protected from moisture, light and repeated temperature cycling. Once in solution, oxidation proceeds faster.

Frequently asked questions

Is MOTS-c the same as humanin?

No. Both are mitochondrial-derived peptides, but humanin is encoded in the 16S rRNA region and has a different sequence and length.

What is the CAS number of MOTS-c?

1627580-64-6.

Does FLASK list MOTS-c?

Yes, as MOTS-c 10 mg, with sequence, formula and CAS number on the product page.