Semax + Selank 2 Vials

What does the Semax + Selank set contain?

The set consists of two separately filled, lyophilised vials, according to the label with 10 mg of Semax and 10 mg of Selank. Both substances are linear, synthetic heptapeptides and follow the same design: a short fragment of a natural peptide is extended at the C-terminus by the sequence Pro-Gly-Pro. The first four amino acids, however, come from two entirely different parent molecules, which makes the two peptides an instructive pair for comparison.

Key data side by side

• Semax: Met-Glu-His-Phe-Pro-Gly-Pro (MEHFPGP), C37H51N9O10S, 813.9 g/mol, CAS 80714-61-0
• Selank: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), C33H57N11O9, 751.9 g/mol, CAS 129954-34-3

The values apply to the free peptides without counter-ions. Two differences stand out at once: only Semax contains sulfur, which comes from the N-terminal methionine, and only Selank carries two strongly basic side chains, in lysine and arginine, whereas Semax has an acidic side chain in glutamic acid.

Two parent sequences, one design principle

Semax takes residues 4 to 7 of adrenocorticotropic hormone (ACTH), Met-Glu-His-Phe; in the literature it is also listed as an analogue of ACTH(4-10). Selank goes back to tuftsin, the tetrapeptide Thr-Lys-Pro-Arg, and is also recorded in databases under the code TP-7. The shared ending Pro-Gly-Pro is the only matching partial sequence; in research catalogues the two are nevertheless often listed together. As single vials, the catalogue lists Semax and Selank in the Neuropeptides category.

Research context

For neither peptide has a single target receptor been conclusively defined. Semax is studied in rodent models in connection with the expression of BDNF and its receptor TrkB in the hippocampus, and with melanocortin receptors. For Selank there are cell culture and animal studies dealing with the expression of genes of GABAergic neurotransmission and of inflammation-related genes. The work cited is preclinical basic research; its results apply only to the model studied in each case.

Analytics at GPeptides

In the set, each heptapeptide can be analysed on its own. Although both molecules are the same length, a difference of around 62 Da separates them in the mass spectrum, so a mix-up of the vials would be noticed immediately. HPLC determines, separately for each peptide, the share of the main peak in the total area of the chromatogram. The products are regularly tested externally by HPLC and mass spectrometry in an independent laboratory; available certificates of analysis can be accessed in the lab area, and where one is missing, the testing is noted there as pending. The structure and key figures of a certificate are explained in the guide to reading a certificate of analysis.