SS-31 Research Peptide FAQ for Scientists: Common Laboratory Questions Answered
Research Notice: This article covers research on SS-31 research peptide and MOTS-C research peptide — available from Palmetto Peptides for laboratory use only.
Research Disclaimer: SS-31 is sold by Palmetto Peptides strictly as a research compound for in vitro and laboratory use only. It is not intended for human or veterinary consumption, administration, or therapeutic use.
For a complete overview of this research area, see the Complete Guide to SS-31 (Elamipretide) Research Peptide from Palmetto Peptides.
This comprehensive FAQ covers the most common questions scientists have about SS-31 research peptide in laboratory settings. Researchers can order SS-31 research peptide from Palmetto Peptides with full lot-specific COA documentation. See also: MOTS-C research and mitochondrial function research.
Mechanism and Science
What is SS-31?
SS-31 is a synthetic tetrapeptide research compound with the sequence D-Arg-Dmt-Lys-Phe-NH2 (where Dmt is 2',6'-dimethyltyrosine). It belongs to the Szeto-Schiller peptide family and is studied for its mitochondria-targeting and cardiolipin-binding properties. Also known as elamipretide or MTP-131.
How does SS-31 reach mitochondria in cell-based models?
SS-31 carries net charge approximately +3 at physiological pH. The large negative membrane potential of the inner mitochondrial membrane (approximately -180 mV) creates an electrostatic driving force that concentrates cationic compounds inside mitochondria. This mechanism does not require a specific receptor or active transport process.
What is the molecular weight of SS-31?
Approximately 639.80 g/mol. Molecular formula C32H49N9O5. Monoisotopic mass approximately 639.37 g/mol.
What is cardiolipin and why does it matter for SS-31 research?
Cardiolipin is a unique dimeric phospholipid found almost exclusively in the inner mitochondrial membrane. It carries net charge -2 and plays critical structural roles in supporting electron transport chain complexes and cristae architecture. SS-31 cationic and aromatic residues allow cardiolipin binding in laboratory membrane models.
How does SS-31 differ from MitoQ or SkQ1?
MitoQ and SkQ1 use a triphenylphosphonium (TPP)-conjugated antioxidant scaffold without defined cardiolipin binding. SS-31 uses a peptide-based aromatic-cationic scaffold with specific cardiolipin interaction — making them complementary but mechanistically distinct research tools.
Researchers seeking a broader review can consult the Complete Guide to SS-31 (Elamipretide) Research Peptide, which covers the full research landscape in detail.
Purity and Quality
What purity grade is appropriate for in vitro mitochondrial assays?
At least 95% HPLC purity for standard cell-based assays. 98% or above recommended for quantitative binding studies, dose-response experiments, or publication-quality research.
What is the difference between SS-31 and elamipretide?
They are the same compound. SS-31 is the original research designation; elamipretide (MTP-131) is the International Nonproprietary Name (INN) assigned for clinical use. The compound is identical.
Reconstitution, Storage, and Handling
How should SS-31 be reconstituted?
Reconstitute lyophilized SS-31 in sterile ultrapure water or sterile PBS (pH 7.4) at your desired stock concentration (typically 1-10 mM). Allow vial to reach room temperature before opening. Mix by gentle pipetting. Filter through 0.22 um sterile membrane for cell culture use.
What are the recommended storage conditions?
Lyophilized SS-31 at -20C or -80C desiccated dark. Reconstituted stocks aliquoted into single-use volumes at -80C protected from light. Maximum 3 freeze-thaw cycles. Working solutions used same-day.
Why is SS-31 stored protected from light?
The Dmt residue contains a phenolic aromatic ring susceptible to photo-oxidation. Both lyophilized powder and reconstituted solutions should be in amber tubes or foil-wrapped containers.
Assay Design
What concentration of SS-31 should I use?
Published studies use 1 nM to 10 uM; most cell-based assays use 100 nM to 1 uM. Always run a dose-response experiment for your specific cell type and assay system.
Does serum in cell culture medium affect SS-31?
Serum albumin can bind cationic peptides, potentially reducing free SS-31 concentration. Some researchers use serum-free conditions during treatment windows to minimize this. Whether this matters depends on concentration used and sensitivity of your endpoint.
For additional research context: NAD+ research, longevity peptide research, cellular health research, BPC-157 and TB-500 research. Order SS-31 research peptide here.
See Also: SS-31 Research Peptide: Complete Guide