SS-31 10mg

What SS-31 is

SS-31 is a synthetic tetrapeptide amide, D-Arg-Dmt-Lys-Phe-NH2, with the International Nonproprietary Name elamipretide. Half of its residues are non-standard. Position one is D-arginine, the mirror image of the usual L form, and position two is Dmt, 2′,6′-dimethyl-L-tyrosine, a tyrosine with methyl groups on the ring on either side of its attachment point. L-lysine and L-phenylalanine complete the chain, and the C-terminus is a primary amide.

The code comes from the Szeto-Schiller series of aromatic-cationic tetrapeptides, with 31 marking this compound’s number in that series. Its siblings use the same building blocks in a different order or with a single substitution, and several have identical or very similar masses. A label reading SS-31 without the full sequence, including the D-configuration and the amide, is therefore an incomplete identity statement.

SS-31 10mg specification

How SS-31 is analyzed

SS-31 alternates cationic and aromatic residues. Arginine, lysine and the free N-terminal amine carry three positive charges in an acidic mobile phase, and the amide removes the negative charge a free acid would add, so the molecule is small and strongly basic. It retains modestly on C18 and elutes fairly early, though later than a purely polar tripeptide thanks to the Dmt and Phe rings, and its retention shifts noticeably with TFA concentration. The Dmt phenol gives a measurable but weak 280 nm response; purity is taken at 214 or 220 nm. Two identity traps are specific to it: an L-Arg diastereomer has exactly the same mass and may co-elute on an achiral column, and a free-acid variant sits only about 1 Da above the amide. With three basic sites on a molecule this light, a tris-trifluoroacetate salt adds roughly 340 g/mol, so counter-ion is a large share of the weighed powder.

SS-31’s reverse-phase HPLC result is published for this product on this page. Vials leave without lot or batch numbering, and the crimp and cap color is the match between each vial and that published test.

Research contexts for SS-31

• Peptide-lipid interaction studies using cardiolipin-containing model membranes and liposomes
• Comparative characterization of Szeto-Schiller series tetrapeptides and their sequence isomers
• Analytical methods for non-proteinogenic residues such as 2′,6′-dimethyltyrosine
• Salt-form and net peptide content determination for small, highly charged peptides

SS-31 is intended only for in-vitro and analytical bench research and is not suitable for use in people or animals.

SS-31 questions

Is SS-31 the same compound as elamipretide?

Yes. SS-31 is the original series code and elamipretide the nonproprietary name for the same D-Arg-Dmt-Lys-Phe-NH2 structure.

What is Dmt in the SS-31 sequence?

Dmt is 2′,6′-dimethyl-L-tyrosine, a non-proteinogenic residue carrying two extra methyl groups on the aromatic ring. It accounts for the weak 280 nm absorbance.

Why can a mass spectrum not confirm the D-arginine?

D- and L-arginine have the same atoms, so both versions of the peptide weigh the same. Stereochemistry has to be addressed chromatographically, ideally with a method able to resolve the two diastereomers.