SS-31 Sequence
SS-31 is a modified tetrapeptide with the condensed structural representation H-D-Arg-Tyr(2,6-diMe)-Lys-Phe-NH2. PubChem also represents the biological sequence as RXKF.
Molecular Characteristics
| Characteristic | Information |
|---|---|
| Name | SS-31 / Elamipretide |
| Length | Four residues |
| CAS | 736992-21-5 |
| PubChem CID | 11764719 |
| Formula | C32H49N9O5 |
| Molecular weight | Approximately 639.8 g/mol |
| Condensed representation | H-D-Arg-Tyr(2,6-diMe)-Lys-Phe-NH2 |
Why SS-31 Is Not a Conventional Four-Letter Peptide
The shorthand sequence RXKF does not communicate all of the molecular detail. The first residue is D-arginine, the tyrosine-like residue contains a 2,6-dimethyl modification, and the C terminus is amidated. These features matter analytically because stereochemistry and residue modification influence molecular identity.
Stereochemistry Matters
Synthetic peptide quality cannot be determined from nominal sequence alone. D/L stereochemistry can create analytical challenges because stereoisomers may share many physical and chemical properties while differing in configuration.
Parent Peptide vs. Salt Forms
Parent elamipretide is not the only chemical representation found in databases. Salt- and counterion-associated forms may have different formulas and represented molecular weights. Analytical interpretation should therefore use the actual material form being evaluated.
Why Molecular Weight Matters in LC-MS
Mass spectrometry is useful for synthetic peptides because the expected structure is known in advance. Measured spectra can contain different charge states, isotopic envelopes and adducts, so molecular-weight information should be interpreted in the context of the documented material form and analytical method.
Sequence, Identity and Purity Are Different Questions
Sequence describes the intended residue order. Molecular identity asks whether analytical evidence is consistent with that molecule. Purity evaluates sample composition under a defined method. Quantity asks how much target material is present.
Why the Exact SS-31 Structure Is Scientifically Relevant
The peptide’s compact aromatic-cationic architecture is central to its research history as a mitochondria-targeting peptide. Structural characteristics have been investigated in connection with membrane partitioning, cardiolipin interaction and mitochondrial localization.
Related SS-31 Research Resources
Selected Scientific References
FOR LABORATORY RESEARCH ONLY. NOT FOR HUMAN OR VETERINARY USE OR CONSUMPTION.
Continue the SS-31 Research Cluster
View SS-31 10 mg Research Material for the product-specific research-material page.
