SS-31 (also known as Elamipretide, MTP-131, Bendavia) is a synthetic cell-permeable tetrapeptide with the sequence D-Arg-Dmt-Lys-Phe-NH2 (where Dmt = 2′,6′-dimethyltyrosine). It selectively targets the inner mitochondrial membrane by binding to cardiolipin, a phospholipid critical for maintaining mitochondrial cristae structure, electron transport chain organization, and cytochrome c function. This cardiolipin interaction stabilizes membrane architecture and optimizes mitochondrial bioenergetics without acting as a conventional free-radical scavenger. Research compound — for laboratory use only.
Product Specifications
| Compound Name | SS-31 (Elamipretide / MTP-131) |
| CAS Registry Number | 736992-21-5 |
| Molecular Weight | 639.80 g/mol |
| Molecular Formula | C32H49N9O5 |
| Sequence | D-Arg-Dmt-Lys-Phe-NH2 |
| PubChem CID | 11764719 |
| Purity | ≥99% (HPLC) |
| Physical Form | Lyophilized powder |
| Solubility | Freely soluble in sterile water and bacteriostatic water |
| Storage | Store lyophilized at -20°C. Reconstituted solution stable at 2-8°C for up to 28 days. Avoid repeated freeze-thaw cycles. |
| Catalog Size | 10 mg |
Structural Overview
SS-31 belongs to the Szeto-Schiller (SS) family of mitochondria-targeting peptides, originally discovered during opioid receptor research. Its alternating aromatic-cationic motif (aromatic–basic–aromatic–basic) enables rapid, energy-independent cell penetration and selective accumulation at the inner mitochondrial membrane within minutes of exposure.
Key structural features:
- D-Arginine at position 1 — Provides cationic charge for membrane interaction and confers resistance to aminopeptidase degradation
- 2′,6′-Dimethyltyrosine (Dmt) at position 2 — Modified aromatic residue that enhances membrane partitioning and cardiolipin binding affinity
- Lysine at position 3 — Additional basic residue contributing to the cationic amphipathic character
- Phenylalanine-NH2 at position 4 — C-terminal amidation improves metabolic stability and membrane interaction
The net +3 charge at physiological pH drives electrostatic concentration at the highly negative inner mitochondrial membrane, achieving >1,000-fold accumulation relative to extracellular concentration.
Mechanism of Action
Unlike conventional antioxidants that scavenge reactive oxygen species after formation, SS-31 acts upstream at the site of ROS generation by stabilizing the electron transport chain itself:
- Cardiolipin binding: SS-31 interacts with cardiolipin through electrostatic and hydrophobic contacts, stabilizing the cristae architecture that houses respiratory chain supercomplexes
- Electron transport optimization: By preserving cardiolipin-dependent supercomplex assembly (Complexes I/III/IV), SS-31 facilitates efficient electron transfer and reduces electron leak that generates superoxide
- Cytochrome c modulation: SS-31 promotes the electron carrier function of cytochrome c while inhibiting its peroxidase activity — a key distinction from traditional antioxidant approaches
- Cristae remodeling: Research demonstrates that SS-31 promotes restoration of inner membrane cristae curvature, improving the structural basis for oxidative phosphorylation
- ADP sensitivity: SS-31 has been shown to improve mitochondrial ADP sensitivity through interactions with the adenine nucleotide translocator (ANT), enhancing the coupling between energy demand and ATP production
Research Context
SS-31 has been investigated across a broad range of research models examining mitochondrial dysfunction:
- Cardiac research models: Extensively studied in models examining ischemia-reperfusion, age-related cardiac dysfunction, and cardiomyopathy associated with cardiolipin remodeling defects
- Renal research: Investigated in models of acute kidney injury and chronic kidney disease, where mitochondrial dysfunction contributes to tubular cell damage
- Skeletal muscle research: Studied in aging models examining the relationship between mitochondrial ADP sensitivity, muscle fatigue resistance, and exercise capacity
- Neurodegenerative research: Examined in models investigating mitochondrial contributions to neuronal dysfunction, including oxidative phosphorylation deficits and synaptic energy failure
- Ophthalmic research: Investigated in retinal models where photoreceptor and retinal pigment epithelium cells have high mitochondrial density and energy demands
Handling & Reconstitution
SS-31 is a water-soluble tetrapeptide that reconstitutes readily:
- Recommended solvent: Sterile water or bacteriostatic water for injection
- Reconstitution: Add solvent slowly along the vial wall, then gently swirl — do not vortex aggressively
- Lyophilized storage: -20°C, protected from light and moisture
- Reconstituted storage: 2-8°C, use within 28 days
- Stability note: SS-31 is relatively stable in aqueous solution due to the D-amino acid and C-terminal amidation, but prolonged storage above 8°C may reduce activity
Quality Assurance
Every batch of SS-31 from Chameleon Peptides is independently tested for identity and purity:
- High-performance liquid chromatography (HPLC) — purity ≥99%
- Mass spectrometry (MS) — molecular weight confirmation
- Certificate of Analysis (COA) available on our Testing page
FOR RESEARCH USE ONLY — NOT FOR HUMAN CONSUMPTION