SS-31

SS-31, also catalogued as MTP-131 and elamipretide, is a small cell-permeable tetrapeptide that accumulates in the inner mitochondrial membrane, where it selectively binds cardiolipin, a phospholipid found almost nowhere else in the cell. By anchoring to cardiolipin, SS-31 is reported to protect the lipid from peroxidation and preserve its interaction with cytochrome c, which keeps cristae junctions tightly folded and holds the electron transport chain supercomplexes in their efficient arrangement. In isolated mitochondria and cell models, reported downstream effects are higher mitochondrial ATP synthesis, less electron leak from complexes I and III, lower reactive oxygen species (ROS) generation at the source, and resistance to mitochondrial permeability transition pore opening.