SS-31 is a synthetic aromatic–cationic tetrapeptide, H-D-Arg-Dmt-Lys-Phe-NH2, where Dmt is 2′,6′-dimethyltyrosine. It is a member of the Szeto–Schiller peptide family, in which aromatic and basic residues alternate. At neutral pH it carries a net charge of +3, and the D-arginine and C-terminal amide make it resistant to aminopeptidase degradation.

The peptide is cell-permeable and concentrates at the inner mitochondrial membrane. It has been reported to bind cardiolipin and to modulate the cytochrome c/cardiolipin complex, and biophysical studies show it binds lipid bilayers and alters membrane surface electrostatics. Cross-linking mass spectrometry has mapped its interactions with mitochondrial proteins, including electron transport chain components.

SS-31 is cited in research on mitochondrial membrane biophysics, cardiolipin biology and electron transport chain function in isolated mitochondria and cultured cells.

Research use only. This material is sold for in-vitro laboratory research and development purposes exclusively. It is not a drug, food, or dietary supplement, has not been evaluated by the FDA, and must not be used in humans or animals.