A four-residue peptide that accumulates in the inner mitochondrial membrane without a targeting signal, and binds a phospholipid rather than a protein.
- Sequence
- D-Arg-Dmt-Lys-Phe-NH2 (Dmt = 2′,6′-dimethyltyrosine)
- Synonym
- elamipretide
- Molecular formula
- C32H49N9O5 (free base)
- Molecular weight
- 639.8 g/mol (free base)
- CAS number
- 736992-21-5
- Appearance
- white lyophilised powder
- Strengths available
- 10mg, 50mg per vial
- Purity
- ≥99% by HPLC, identity confirmed by mass spectrometry
- Released against
- the Certificate of Analysis for its own batch
About SS-31
SS-31, known in the clinical literature as elamipretide, is D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2′,6′-dimethyltyrosine. It belongs to the Szeto-Schiller series of mitochondria-targeted tetrapeptides. Alternating aromatic and basic residues give it a net positive charge spread over a small lipophilic frame, enough for it to partition into the inner mitochondrial membrane and concentrate there by a factor of more than a thousand relative to cytosol, without a transporter.
Its binding partner is cardiolipin, a phospholipid found almost exclusively in the inner mitochondrial membrane, where it organises the respiratory chain complexes and the cristae that hold them. SS-31 binds cardiolipin, and the reported effect is to stabilise that organisation.
What the research covers
Targeting a lipid rather than a receptor changes the shape of the pharmacology. There is no receptor-subtype selectivity to establish and no agonist or antagonist distinction, and the dose-response relationship is governed by partitioning into a membrane compartment rather than occupancy of a binding site, so the work reads more like membrane biophysics than receptor pharmacology.
Published work reports protection of cristae structure and respiratory chain supercomplex function under stress, reduced mitochondrial reactive oxygen species production, and benefit in ischaemia-reperfusion, heart failure, acute kidney injury and mitochondrial myopathy models. Clinical trials have been run in primary mitochondrial myopathy, with mixed results that are worth reading directly rather than through summaries. Published work is indexed on PubMed.
Handling SS-31
Supplied lyophilised. Being strongly cationic, this peptide adsorbs to glass and standard plasticware far more readily than a neutral sequence of the same length, and the loss from a dilute solution can be large enough to confound a concentration series.
Low-binding plasticware is strongly advisable rather than optional. Prepare working solutions fresh, avoid long dilution chains, and store sealed vials at -20°C. Solvent options are under reconstitution supplies.
Common questions about SS-31
Is SS-31 the same as elamipretide?
Yes. Elamipretide is the name used in clinical development; SS-31 comes from the Szeto-Schiller peptide series.
How does SS-31 reach mitochondria?
Its alternating aromatic and positively charged residues let it partition into the inner mitochondrial membrane and concentrate there without a transporter or targeting sequence.
What is cardiolipin?
A phospholipid found almost only in the inner mitochondrial membrane, which organises the respiratory chain complexes. It is SS-31’s binding partner.
Why does SS-31 need low-binding plasticware?
It is strongly cationic and adsorbs heavily to glass and standard plastics, which can distort low concentrations considerably.
How should SS-31 be stored?
Sealed vials at -20°C. Working solutions are prepared fresh in low-binding plasticware.
