SS-31

A synthetic aromatic-cationic tetrapeptide studied as a research tool for its selective interaction with cardiolipin on the inner mitochondrial membrane.

Molecular Profile

Type
Synthetic aromatic-cationic tetrapeptide (C-terminally amidated, mitochondria-targeted)
Molecular formula
C32H49N9O5
Molecular weight
639.8 g/mol
CAS number
736992-21-5
Amino acids
4
Sequence
D-Arg-2',6'-dimethyl-Tyr-Lys-Phe-NH2
Modification
N-terminal D-arginine (proteolytic resistance); 2',6'-dimethyltyrosine at position 2; C-terminal amide.

Mechanism & Target Class

SS-31 is a water-soluble aromatic-cationic tetrapeptide of the Szeto–Schiller series characterized by an alternating motif of cationic (D-Arg, Lys) and aromatic (2',6'-dimethyltyrosine, Phe) side chains that confers a net positive charge while maintaining membrane permeability. In published research it is characterized as concentrating selectively in the inner mitochondrial membrane through electrostatic and hydrophobic interactions, where it associates with the anionic phospholipid cardiolipin. Mechanistic work describes binding at the membrane interfacial region and modulation of membrane surface electrostatics, lipid packing, and the cardiolipin–cytochrome c interaction. Its target class is a membrane phospholipid (cardiolipin) and associated cardiolipin-binding proteins of the oxidative-phosphorylation and 2-oxoglutarate-metabolism machinery — it is not described as a cell-surface receptor ligand.

Storage & Handling

Lyophilized
2–8 °C routine handling; −20 °C or below long-term; protect from light. Lyophilized material reported stable up to 24 months at recommended conditions.
Handling
The N-terminal D-arginine and 2',6'-dimethyltyrosine modifications confer resistance to enzymatic degradation relative to all-L peptides. Water-soluble; brief room-temperature exposure during transport is generally tolerated.

Primary Database

PubChem CID 11764719 ↗

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