SS-31, published under the generic name elamipretide and also referenced as MTP-131 in some literature, is a synthetic tetrapeptide designed to target the inner mitochondrial membrane. It belongs to the Szeto-Schiller peptide series, and its defining property is selective association with cardiolipin, a phospholipid found almost exclusively in the inner mitochondrial membrane.
Mechanistic context
Cardiolipin is essential to the structural organisation of the respiratory chain and to the function of cytochrome c. In pathological states, cardiolipin peroxidation disrupts this organisation and converts cytochrome c into a peroxidase, contributing to mitochondrial dysfunction. SS-31 is proposed to bind cardiolipin and stabilise these interactions, improving electron transport efficiency. The mechanism is therefore structural and membrane-associated rather than receptor-mediated, which distinguishes it sharply from most compounds in this catalogue.
Published findings
Birk and colleagues (2014) reported that targeting mitochondrial cardiolipin and the cytochrome c/cardiolipin complex promotes electron transport and optimises mitochondrial ATP synthesis, establishing the mechanistic premise.
Mitchell and colleagues (2020) reported that the peptide binds lipid bilayers and modulates surface electrostatics as a key component of its mechanism — a biophysical study that refines the mechanistic account beyond simple binding to include effects on membrane surface charge.
Karaa and colleagues (2018) reported a randomised dose-escalation trial of elamipretide in adults with primary mitochondrial myopathy, providing controlled human clinical data. Pharaoh and colleagues (2023) reported improved ADP sensitivity in aged mitochondria through increased uptake via the adenine nucleotide translocator, extending the mechanism to a specific transport protein in an ageing context.
Scope and limitations of the evidence
SS-31 has among the strongest evidence bases in this catalogue, spanning biophysical characterisation, isolated mitochondrial studies and a randomised human trial in a defined patient population. The Karaa trial is a genuine controlled clinical study rather than an open-label observation.
The limitation is population specificity. Primary mitochondrial myopathy is a defined genetic disease group, and effects observed there do not establish effects in healthy mitochondria or in other conditions. The ageing work by Pharaoh and colleagues is preclinical and addresses a different biological context.
Use in experimental design
Because the mechanism is membrane-associated, experimental systems must preserve mitochondrial membrane integrity for the compound to behave as described; harsh isolation protocols that disrupt cristae architecture may obscure effects. Cardiolipin content varies by tissue and declines with age, so tissue selection is a meaningful variable rather than a matter of convenience. Where respiratory function is the endpoint, substrate choice and ADP state determine which aspect of the mechanism is being tested, as the Pharaoh work on ADP sensitivity illustrates.
Analytical and handling notes
Each lot is supplied with a certificate of analysis reporting RP-HPLC purity, mass identification by ESI-MS and label claim recovery, together with an independent ICP-MS elemental impurities report. Purity figures apply to the specific lot tested and should be read against the lot documentation rather than inferred from generic reference material. Storage guidance appears on the technical data sheet; the exact supplied salt form, counterion and hydration state are lot and supplier specific and should be reconciled against supplier documentation before quantitative work.
This material is supplied for laboratory research use only. It is not a drug, is not intended for human or veterinary use, and no statement above should be read as a claim of therapeutic effect.
