SS-31

SS-31 is a synthetic tetrapeptide, four amino acid residues in length, with the sequence D-Arg-2,6-dimethylTyr-Lys-Phe-NH2.

Two structural features define it. The alternating aromatic-cationic motif gives the molecule a net positive charge at physiological pH, and the D-configuration arginine at the N-terminus confers resistance to aminopeptidase cleavage that an all-L sequence would not have.

It belongs to the Szeto-Schiller class of mitochondria-targeted peptides, characterised in published work by selective association with cardiolipin, a phospholipid of the inner mitochondrial membrane. That binding affinity is the property on which the class is defined and studied in preclinical models.

Supplied here as 10mg of lyophilised powder in a 3ml vial.

Supplied as a lyophilised (freeze-dried) powder in a sealed vial under vacuum. Lyophilisation removes water by sublimation, which is what allows a peptide to remain stable at ambient temperature during transit where a solution would degrade.

Reconstitution in a laboratory setting is typically performed with bacteriostatic water, introduced slowly against the vial wall rather than directly onto the powder cake. Peptide bonds are susceptible to shear, so the vial is swirled to dissolve rather than shaken.

Lyophilised and sealed, the vial is stable at 2 to 8 degrees Celsius and tolerates ambient temperature in transit. For storage beyond several months, minus 20 degrees Celsius is standard.

Once in solution the stability window shortens considerably and refrigeration is required. Repeated freeze-thaw cycles are the most common cause of degradation in a reconstituted peptide, so solutions are generally aliquoted rather than frozen and thawed as a single volume.

Every batch is independently tested through seven rounds of analysis. Identity is confirmed by mass spectrometry and purity quantified by reverse-phase HPLC, with the resulting Certificate of Analysis published against the specific batch rather than the product line.

Testing is performed by third-party laboratories operating to ISO 17025. The COA for the batch currently shipping is linked from this page and archived at /lab-tests.