What the molecule is
Tesamorelin is a synthetic analogue of human growth hormone releasing hormone, a forty four residue peptide with the sequence YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL and an average mass near 5,135.9 daltons. It is supplied as a lyophilised powder, acetate salt.
Growth hormone releasing hormone itself was isolated and sequenced in 1982 by two groups working on pancreatic tumours that had produced acromegaly, one led by Roger Guillemin and one by Jean Rivier and Wylie Vale. The native peptide is produced in the hypothalamus and acts on the anterior pituitary.
Native growth hormone releasing hormone is cleaved rapidly at the amino terminus by dipeptidyl peptidase 4, which limits its working lifetime. Tesamorelin carries a trans three hexenoyl group attached to the amino terminal tyrosine. That modification slows the enzymatic clipping and gives a molecule that survives longer in a biological matrix than the unmodified forty four residue peptide.
Published research context
The growth hormone axis has been studied for decades, and growth hormone releasing hormone analogues are standard tools in that work. Published research areas include pituitary cell culture systems measuring growth hormone release, receptor binding and selectivity at the growth hormone releasing hormone receptor, and rodent models examining the regulation of the axis.
Tesamorelin has been through registered clinical development, which is unusual for a peptide sold into the research supply market and means more published characterisation data exists for it than for many catalogue items. That literature concerns the compound as a registered product and is separate from the research use supply covered here.
A point of comparison worth understanding is the difference between this class and the growth hormone secretagogues, which act at a different receptor, the ghrelin receptor, and reach the same axis by another route. Papers in this area frequently compare the two classes, so knowing which receptor a given compound engages is the first thing to establish when reading the literature.
As with every item in this catalogue, the material supplied is for laboratory research. Nothing in the published literature changes that, and the peptide is not supplied for any use involving people or animals outside a laboratory setting.
How each lot is characterised
A forty four residue peptide is long enough that synthesis related impurities become the main analytical concern. Deletion sequences, where a single residue failed to couple during chain assembly, are the most common, and they are close enough in mass to the target that chromatographic separation matters as much as the mass measurement.
Purity is measured by reversed phase high performance liquid chromatography with detection at 214 nanometres and reported as main peak area over total area. Identity is confirmed by electrospray ionisation mass spectrometry against the theoretical mass calculated from the sequence and the hexenoyl modification.
The certificate also records appearance, net peptide content by amino acid analysis, water content and counter ion. For a peptide with many charged residues, net peptide content is worth reading carefully, because the acetate and bound water can make up a meaningful fraction of the vial mass.
Handling on the bench
Store the unopened vial at minus twenty degrees, dark and desiccated. Bring it to room temperature before opening so that moisture does not condense onto the cold cake.
Reconstitute with bacteriostatic water, running the solvent slowly down the inside wall of the vial and swirling to dissolve. Do not shake. Long peptides with extended helical regions are more prone to aggregation at an air and liquid interface than short ones, and vigorous mixing creates exactly that interface.
Refrigerate after reconstitution and aliquot for single use. Avoid repeated freeze and thaw cycles. If the solution is to be held for any length of time, note that peptides with asparagine and glutamine residues can undergo slow deamidation in aqueous buffer, which shows up as a shoulder on the main chromatographic peak on reanalysis.
Specification
| Form | Lyophilised powder, acetate salt |
|---|---|
| Sequence | YADAIFTNSYRKVLGQLSARKLLQDIMSRQQGESNQERGARARL |
| Residues | 44 |
| Average mass | 5,135.9 Da |
| Fill size | 20 mg |
| Storage | Minus 20 degrees, dark and desiccated |
References
- Guillemin R, Brazeau P, Bohlen P, Esch F, Ling N, Wehrenberg WB (1982). Growth hormone-releasing factor from a human pancreatic tumor that caused acromegaly. Science, volume 218.
- Rivier J, Spiess J, Thorner M, Vale W (1982). Characterization of a growth hormone-releasing factor from a human pancreatic islet tumour. Nature, volume 300.
For research use only
Products are supplied for laboratory research by qualified researchers and institutions. They are not for human or veterinary use, not for diagnostic or therapeutic use, and are not drugs, foods or cosmetics.