Research Protocols / Longevity
SS-31 research protocols: a peptide that targets a lipid, not a receptor
Most research peptides work by binding a receptor. SS-31 works by concentrating in a specific membrane and binding a phospholipid found essentially nowhere else in the cell. That mechanism is worth understanding properly.
SS-31, developed clinically under the name elamipretide, is a tetrapeptide with an unusual alternating aromatic-cationic structure (D-Arg-dimethylTyr-Lys-Phe-NH2). It belongs to the Szeto-Schiller peptide family, and its defining property is that it accumulates in the inner mitochondrial membrane at concentrations reported to be roughly a thousandfold above cytosolic levels, without requiring a transporter and without depending on membrane potential.
Cardiolipin: the actual target
Cardiolipin is a dimeric phospholipid found almost exclusively in the inner mitochondrial membrane, where it constitutes a substantial fraction of total lipid. It is not structural filler. Cardiolipin organises the respiratory chain complexes into supercomplexes, stabilises cristae curvature, and holds cytochrome c at the membrane surface.
Two consequences make it a compelling target:
- Cardiolipin is peroxidation-prone. Its four unsaturated acyl chains sit directly adjacent to the electron transport chain, the cell's largest source of reactive oxygen species. Peroxidised cardiolipin loses its structural role.
- Peroxidised cardiolipin releases cytochrome c. That release is an initiating step in intrinsic apoptosis, which links cardiolipin damage directly to cell death pathways.
SS-31 binds cardiolipin through electrostatic and hydrophobic interaction. Reported effects include stabilisation of cristae architecture, improved supercomplex assembly and electron transport efficiency, and reduced peroxidation. Notably, it is described in the literature as protecting cardiolipin's structural function rather than acting as a general antioxidant, a distinction that separates it from the broad-spectrum antioxidant compounds that largely failed to reproduce in trials.
The mechanistic bet behind SS-31 is that mitochondrial dysfunction in disease is often a membrane organisation problem, not a free radical quantity problem.
Clinical trial context
Elamipretide has been evaluated in registered human clinical trials for primary mitochondrial myopathy, Barth syndrome, and certain ophthalmic indications. That programme is genuinely informative for researchers because it produced published human pharmacokinetic and safety data, which is rare in this catalogue. It also means published human results were generated with pharmaceutical-grade material under trial conditions. Research reference standard material is not clinical trial material, and the two are not interchangeable for any purpose.
Reconstitution for a 10 mg vial
Our SS-31 ships as a 10 mg lyophilized vial, 99.15% HPLC purity on the current lot.
| Water added | Concentration | Per 0.1 mL |
|---|---|---|
| 2 mL | 5 mg/mL | 500 mcg |
| 5 mL | 2 mg/mL | 200 mcg |
| 10 mL | 1 mg/mL | 100 mcg |
As a tetrapeptide, SS-31 handles like other short peptides: reasonably freeze-thaw tolerant, water soluble, stable lyophilized at minus 20 degrees Celsius. The cationic character means it can adsorb to some plastic surfaces at very low concentrations, so for dilute working solutions use low-binding tubes if your assay is sensitive to small losses.
Related mitochondrial research
SS-31 and MOTS-c are both mitochondrial-focused but act on entirely different levels: SS-31 on inner membrane lipid organisation, MOTS-c on retrograde metabolic signalling through AMPK. Our SS-31 mechanism overview covers the membrane biology in more depth, and the reference page carries sequence and PubMed entry points.
Sourcing and verification
Purity determines whether a result is reproducible. Every Lumera Labs lot ships with a lot-specific certificate of analysis reporting HPLC-UV purity, and those certificates are published at Lab Results before you order rather than emailed afterward. Orders ship from within Canada in 24 to 48 hours, free over $200 CAD, which removes customs exposure and keeps transit short for temperature-sensitive material.
FAQ
Is SS-31 the same as elamipretide?
Yes. SS-31 is the research designation from the Szeto-Schiller peptide series; elamipretide is the name used in clinical development. Published human trial data appears under the elamipretide name.
What does SS-31 bind to?
Cardiolipin, a dimeric phospholipid found almost exclusively in the inner mitochondrial membrane. Unlike most research peptides it targets a lipid rather than a receptor, which is why it concentrates in that membrane without a transporter.
Is SS-31 an antioxidant?
Not in the conventional sense. The literature describes it as protecting cardiolipin's structural role in organising respiratory supercomplexes and stabilising cristae, rather than acting as a general free radical scavenger. That distinction separates it from broad-spectrum antioxidants.
How do I reconstitute a 10 mg SS-31 vial?
2 mL gives 5 mg/mL, 5 mL gives 2 mg/mL, 10 mL gives 1 mg/mL. Its cationic character means it can adsorb to some plastics at very low concentrations, so use low-binding tubes for dilute working solutions.
Why does cardiolipin peroxidation matter?
Cardiolipin's unsaturated acyl chains sit adjacent to the electron transport chain, the largest cellular source of reactive oxygen species. Peroxidised cardiolipin loses its structural role and releases cytochrome c, an initiating step in intrinsic apoptosis.
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