SS-31 (Elamipretide):
Mitochondrial Membrane Protection Research
SS-31 (Elamipretide; Szeto-Schiller peptide 31) is a mitochondria-targeted tetrapeptide that selectively concentrates in the inner mitochondrial membrane and stabilizes cardiolipin — a critical phospholipid for electron transport chain function.
What Is SS-31?
SS-31 (D-Arg-2’6’Dmt-Lys-Phe-NH₂; also known as Elamipretide or MTP-131) is a synthetic aromatic-cationic tetrapeptide designed by Hazel Szeto and Peter Schiller to selectively target the inner mitochondrial membrane (IMM). Its amphipathic structure — alternating aromatic and cationic residues — allows it to concentrate ~1,000-fold within the IMM without causing membrane depolarization.
SS-31 binds directly to cardiolipin, a phospholipid exclusive to the IMM that scaffolds respiratory chain supercomplexes (respirasomes). By stabilizing cardiolipin and protecting it from peroxidation, SS-31 maintains electron transport chain (ETC) efficiency and reduces mitochondrial reactive oxygen species (ROS) production. Lumen Peppers provides research-grade SS-31 for in vitro and preclinical investigation only.
Key Research Findings
SS-31 research spans cardiac ischemia, neurodegeneration, kidney injury, age-related mitochondrial dysfunction, and metabolic disease models.
Cardiac Ischemia-Reperfusion Protection
SS-31 significantly reduces infarct size in rodent and large-animal cardiac ischemia-reperfusion (I/R) models. Pre- and post-ischemic SS-31 administration preserves ATP production, maintains mitochondrial membrane potential, and reduces cytochrome c release from cardiomyocyte mitochondria during reperfusion injury.
Neurodegenerative Disease Models
SS-31 protects against amyloid-β-induced mitochondrial fragmentation in neuronal cultures, restoring synaptic ATP levels and reducing apoptotic signaling. In ALS and Parkinson's disease models, SS-31 preserves Complex I activity and reduces mitochondrial ROS, attenuating neurodegeneration markers.
Acute Kidney Injury (AKI)
In cisplatin-induced and ischemia-reperfusion kidney injury models, SS-31 reduces renal tubular cell apoptosis, preserves GFR, and maintains proximal tubule mitochondrial cristae structure. The kidney's high mitochondrial density makes it particularly sensitive to SS-31's cardiolipin-protective effects.
Age-Related Mitochondrial Dysfunction
Aged rodents treated with SS-31 show restored mitochondrial respiration in skeletal muscle (increased State 3 respiration, elevated coupling efficiency). SS-31 reverses age-associated decreases in Complex I, III, and IV activities — particularly relevant to sarcopenia and metabolic aging research.
ROS Reduction & Antioxidant Research
SS-31 reduces mitochondrial superoxide (O₂⁻) and hydrogen peroxide (H₂O₂) in isolated mitochondria and cell models without directly scavenging ROS — instead preventing electron leak at Complex I/III by maintaining cardiolipin-ETC supercomplex stability. This mechanistic distinction is pharmacologically significant.
Skeletal Muscle & Exercise Research
SS-31 improves exercise tolerance in aged and dystrophic mouse models. It increases muscle force production, reduces fatigue, and preserves mitochondrial integrity in type I oxidative fibers. SS-31 is used as a research tool to isolate mitochondrial dysfunction from other sarcopenia mechanisms.
Proposed Mechanisms of Action
SS-31's alternating aromatic (Dmt, Phe) and cationic (D-Arg, Lys) residues create an amphipathic structure that electrostatically interacts with cardiolipin's negatively charged phosphate headgroups. This binding stabilizes cardiolipin conformation and prevents its oxidation by cytochrome c peroxidase activity during I/R.
Cardiolipin scaffolds respiratory chain supercomplexes (respirasomes: CI-CIII₂-CIV₁₋₂). By protecting cardiolipin from peroxidation and maintaining its interaction with ETC complexes, SS-31 preserves supercomplex assembly, electron channeling efficiency, and ATP synthesis coupling ratios.
SS-31 does not directly scavenge ROS. Instead, it prevents electron leak at Complex I and III by maintaining supercomplex integrity. Electron leak generates O₂⁻ when electrons bypass the CoQ-cytochrome c sequential pathway — SS-31's cardiolipin stabilization reduces this leak source.
During apoptosis/stress, cytochrome c is released from IMM cardiolipin binding sites into the cytoplasm, activating the intrinsic apoptosis cascade. SS-31 competes with cytochrome c for cardiolipin binding sites, retaining cytochrome c in the IMM and reducing apoptosis initiation in stressed cells.
SS-31 modulates DRP1-mediated mitochondrial fission by reducing cardiolipin oxidation-driven fission signals. In neuronal models, SS-31 shifts the fission/fusion balance toward fusion, restoring elongated mitochondrial networks in Aβ- and MPP⁺-treated cells.
Active Research Applications
Cardiac I/R Research
Infarct size quantification, troponin release, and mitochondrial respiration studies in ex vivo and in vivo cardiac I/R models.
Neurodegeneration Models
Mitochondrial morphology, ROS, and synaptic ATP studies in Alzheimer's, Parkinson's, and ALS preclinical models.
Nephroprotection Studies
Renal tubule mitochondrial integrity, GFR preservation, and apoptosis quantification in cisplatin and I/R AKI models.
Aging & Sarcopenia
Skeletal muscle ETC complex activity, mitochondrial respiration, and force production studies in aged and sedentary rodents.
Mitochondrial Biology
Cardiolipin quantification, supercomplex assembly, oxygen consumption rate (OCR), and electron leak studies using Seahorse or isolated mitochondria.
Drug Discovery Reference
SS-31 as benchmark compound for comparing novel cardiolipin-protective or mitochondria-targeted antioxidant candidates.
Protocol Notes for Researchers
SS-31 (Elamipretide) — Research Grade ≥99%
Research-grade purity ≥99% · Third-party HPLC verified · Ships from the U.S.
All products sold by Lumen Peppers are intended exclusively for in vitro laboratory research and investigative purposes. These compounds are not approved by the FDA for human or veterinary use. They are not drugs, supplements, or medications. Lumen Peppers makes no therapeutic claims. Researchers are solely responsible for ensuring compliance with all applicable laws and regulations in their jurisdiction.