MOTS-c vs SS-31 (Elamipretide)
MOTS-c and SS-31 are both studied in mitochondrial research but approach the organelle from opposite directions. MOTS-c is a mitochondrial-derived signaling peptide that acts on nuclear gene expression and metabolism, while SS-31 is a synthetic peptide that physically targets the inner mitochondrial membrane.
Side-by-Side Comparison
| Property | MOTS-c | SS-31 (Elamipretide) |
|---|---|---|
| Category | Mitochondrial-derived peptide (encoded within the mitochondrial 12S rRNA gene) | Synthetic Szeto-Schiller tetrapeptide (D-Arg-Dmt-Lys-Phe-NH2) |
| Mechanism of Action | Activates AMPK, regulates cellular metabolism; translocates to the nucleus under metabolic stress to modulate nuclear gene expression | Concentrates in the inner mitochondrial membrane and binds cardiolipin; stabilizes cristae structure and electron transport chain function, reduces ROS production |
| Molecular Weight | ~2,174 Da (16 amino acids) | ~640 Da (4 amino acids) |
| Primary Research Focus | Exercise physiology, insulin sensitivity, metabolic homeostasis, aging | Mitochondrial dysfunction, ischemia-reperfusion injury, heart failure, mitochondrial myopathy |
| Origin | Endogenous; one of a small class of peptides encoded by mitochondrial DNA | Fully synthetic; designed for membrane targeting via alternating aromatic-cationic structure |
| Half-Life | Short (minutes to hours); endogenous levels respond to exercise and metabolic stress | ~2-4 hours (estimated, from elamipretide clinical pharmacology) |
| Key Research Citations | Lee et al. (2015), Cell Metab; Reynolds et al. (2021), Nat Commun | Szeto (2014), Br J Pharmacol; Birk et al. (2013), J Am Soc Nephrol |
Key Differences
- MOTS-c is encoded by mitochondrial DNA and functions as a retrograde signal from mitochondria to nucleus; SS-31 is a synthetic compound delivered to mitochondria from outside.
- MOTS-c acts through metabolic signaling (AMPK activation, nuclear gene regulation); SS-31 acts structurally, binding cardiolipin to stabilize the inner membrane and electron transport chain.
- MOTS-c research centers on exercise mimetic and insulin-sensitivity endpoints; SS-31 research centers on protecting mitochondria in injury and disease models, including clinical trials as elamipretide.
- SS-31, at four amino acids, is one of the smallest peptides in mitochondrial research; MOTS-c is a 16-amino-acid signaling peptide.
Research Summary
MOTS-c and SS-31 illustrate two complementary strategies in mitochondrial peptide research. MOTS-c is an endogenous mitochondrial-encoded messenger that reprograms cellular metabolism through AMPK and nuclear gene expression, with research focused on exercise and insulin sensitivity. SS-31 is an engineered cardiolipin-binding tetrapeptide that physically stabilizes the inner mitochondrial membrane, with research focused on rescuing dysfunctional mitochondria in injury and disease models. One is a signal, the other a structural stabilizer.
What is the difference between MOTS-c and SS-31?
MOTS-c is a 16-amino-acid peptide encoded by mitochondrial DNA that signals to the nucleus and activates AMPK, studied for exercise-mimetic and insulin-sensitivity effects. SS-31 (elamipretide) is a synthetic tetrapeptide that binds cardiolipin in the inner mitochondrial membrane, stabilizing the electron transport chain and reducing ROS, studied in mitochondrial dysfunction and ischemia-reperfusion models.
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Disclaimer: All compounds referenced on this page are sold for research and laboratory use only. The comparisons presented are based on published scientific literature and are intended for educational and informational purposes. This content does not constitute medical advice. Researchers should consult primary literature and applicable regulations before designing study protocols.