Selank 10 mg

What is Selank?

Selank is a synthetic, linear heptapeptide and an analogue of the tetrapeptide tuftsin. Besides the common name, databases list the code designation TP-7, the spelling variant Selanc and the sequence notations Thr-Lys-Pro-Arg-Pro-Gly-Pro and TKPRPGP. In the catalogue Selank is listed in the neuropeptides group. No single, established target in the sense of a receptor has been identified for the molecule.

From tuftsin to heptapeptide

Tuftsin consists of the four amino acids threonine, lysine, proline and arginine and is a fragment of the heavy chain of immunoglobulin G from the Fc region. The free tetrapeptide has the molecular formula C21H40N8O6 and a molar mass of 500.6 g/mol (CAS 9063-57-4). Selank extends this sequence at the C-terminus by proline, glycine and proline. The first four positions of the heptapeptide chain are thus identical to tuftsin.

Key data for Selank

• Sequence: Thr-Lys-Pro-Arg-Pro-Gly-Pro (TKPRPGP), free N- and C-terminus
• Molecular formula: C33H57N11O9
• Molar mass: 751.9 g/mol (calculated for the free peptide)
• CAS number: 129954-34-3
• PubChem CID: 11765600

Its characteristic features are three proline residues and the basic side chains of lysine and arginine. Selank contains no sulfur-containing or aromatic amino acids.

Classification: Selank, tuftsin and Semax

Selank shares with Semax a chain length of seven amino acids and the appended Pro-Gly-Pro motif. The front part of the sequence, however, has a different origin: in Semax it is a section of the hormone ACTH, in Selank it is tuftsin, which derives from immunoglobulin G. The composition and mass of the two molecules therefore differ so much that they can be reliably told apart analytically. For comparative work both peptides are available in the Semax + Selank set; the Neuropeptides category gives an overview of the group.

Research context

The preclinical literature on Selank comprises studies in rodents and in cell lines such as IMR-32. One focus is the expression of genes involved in GABAergic neurotransmission. These are gene expression data, not evidence of binding to a GABA receptor. Other studies examine the expression of inflammation-related genes such as chemokines and cytokines, measurements of BDNF in rat brain tissue, and in-vitro experiments with enkephalin-degrading enzymes in human plasma.

Analytics at GPeptides

Selank is tested externally at regular intervals, by HPLC for purity and by mass spectrometry for identity, in each case by an independent laboratory. As the peptide has no aromatic amino acids, UV detection in the chromatogram relies on the absorption of the peptide bonds in the short-wavelength range. In the mass spectrum the measured value is compared with the mass calculated from C33H57N11O9; because of the basic residues lysine and arginine, multiply protonated ions also frequently appear in electrospray ionisation. The lab area shows which certificates have already been published; where a document is missing, the entry there is marked “pending”. How purity figures can be put into context is described in the guide Purity of research peptides.