The tesamorelin peptide is the 44-residue human GHRH sequence, YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL-NH2, carrying a trans-3-hexenoyl group on the N-terminal tyrosine. This guide covers the sequence, what the N-terminal modification changes chemically, and which positions limit stability in solution. It builds on the overview in the tesamorelin structure and in-vitro research profile.
What is the tesamorelin sequence?
| Residues | Sequence |
|---|---|
| 1-10 | YADAIFTNSY |
| 11-20 | RKVLGQLSAR |
| 21-30 | KLLQDIMSRQ |
| 31-40 | QGESNQERGA |
| 41-44 | RARL-NH2 |
The parent peptide has the formula C221H366N72O67S and an average mass near 5135.9 g/mol. The Tesamorelin listing carries the acetate-form figures, C223H370N72O69S and 5195.908 g/mol, the difference being one acetic acid (60.05 Da).
What does the trans-3-hexenoyl group change?
The modification is an N-acyl cap: a six-carbon unsaturated acyl group joined to the alpha-amine of Tyr1. It adds about 96.1 Da (C6H8O) to the peptide and removes the free N-terminal amine. Native GHRH is cleaved after residue 2 by dipeptidyl peptidase IV, which requires that free amine; capping it reduces that cleavage in peptidase-containing media, which is the reason the analog is used for longer incubations.
Which positions limit stability in solution?
| Liability | Position | Mass change | How it is detected |
|---|---|---|---|
| Methionine oxidation | Met27 | +16 Da (sulfoxide) | LC-MS; earlier RP-HPLC elution |
| Deamidation | Asn8, Asn35, Gln residues | +0.98 Da | High-resolution MS; shifted HPLC peak |
| Adsorption and aggregation | Whole 44-mer, high concentration | None | Loss of recovery from low-bind versus standard plastic |
Because the peptide is long and contains an oxidation-prone methionine, lyophilized storage is the default; the basics are explained in what freeze-dried means for peptides.
How is stability checked in the laboratory?
- Run a stability-indicating RP-HPLC gradient and track the main-peak area over time points at 4 C and 37 C in the actual assay buffer.
- Confirm any new peak by LC-MS: +16 Da points to oxidation, +1 Da to deamidation, and a loss of about 96 Da to loss of the hexenoyl cap.
- Use low-bind tubes and single-use aliquots, and record the number of freeze-thaw cycles.
The identity checks referred to above are expanded in confirming tesamorelin identity by CAS and mass spectrometry.
Related research guides
- Sermorelin as a GHRH-analog reference compound
- Tesamorelin 10 mg / 5 mg Vials: Stock Concentration Math (In Vitro)
Research-use note
All materials discussed are supplied for in vitro laboratory research use only, and are not for human or animal use.
