SS-31

Research Context

SS-31 (also referred to as elamipretide) is a synthetic aromatic-cationic tetrapeptide. It is the lead member of the Szeto-Schiller peptide series and is characterised by a strict alternating aromatic-cationic-aromatic-cationic motif that confers a net charge of approximately +3 at physiological pH while retaining sufficient hydrophobicity to cross cell membranes. The peptide selectively partitions into the inner mitochondrial membrane through electrostatic and hydrophobic interactions with cardiolipin.

Preclinical literature has examined SS-31 as a mitochondria-targeted reference compound in studies of cardiolipin stabilisation, electron transport chain function, reactive oxygen species generation, ischaemia-reperfusion models, renal mitochondrial biology, age-related cardiomyopathy models, and primary mitochondrial disease cell systems. It accumulates approximately 5000-fold in isolated mitochondria relative to extracellular concentration.

Chemistry & Structural Modification

Linear 4-residue peptide with sequence H-D-Arg-Dmt-Lys-Phe-NH₂ (D-arginine, 2′,6′-dimethyl-L-tyrosine, L-lysine, L-phenylalanine amide). The D-Arg at the N-terminus and the C-terminal amide both confer resistance to exopeptidase degradation; the Dmt residue provides the aromatic component of the targeting motif.

• Molecular formula: C32H49N9O5 (free base)
• Molecular weight: 639.80 g/mol (free base; acetate and hydrochloride salt forms have higher mass)
• CAS number: 736992-21-5 (free base); PubChem CID 11764719

Lyophilisation & Stability

Supplied as a lyophilised white-to-off-white powder in a sealed glass vial. SS-31 is unusually stable for a peptide of its class given its compact size, D-amino acid at the N-terminus, C-terminal amide, and non-natural Dmt residue, but lyophilisation is still essential to remove water and prevent slow hydrolysis. The dry-state form is stable for extended periods provided the vial is kept sealed, cold, and protected from light.

Storage

Store lyophilised vial at 2 to 8°C, protected from light. (Long-term storage at −20°C is standard practice.)

Reconstituted solution: 2 to 8°C, used within 14 to 30 days. Avoid repeated freeze-thaw cycles.

Quality & Documentation

• Purity: ≥99% by HPLC
• Certificate of Analysis (COA): published on our COA page.