01 / Reference identity
Identity at a glance.
Public records describe Selank as one seven-residue peptide: the tuftsin sequence Thr–Lys–Pro–Arg followed by Pro–Gly–Pro. The values below are for the free peptide; the salt form of a supplied lot follows its own record.
| Sequence, three-letter | Thr–Lys–Pro–Arg–Pro–Gly–Pro |
|---|---|
| Sequence, one-letter | TKPRPGP |
| Length | 7 residues |
| Residues 1–4 | Thr–Lys–Pro–Arg, the tuftsin sequence |
| Residues 5–7 | Pro–Gly–Pro |
| Formula, free peptide | C33H57N11O9 |
| Molecular weight, free peptide | 751.9 g/mol |
| CAS number | 129954-34-3 |
| PubChem CID | 11765600 |
- SemaxSemax ends in the same Pro–Gly–Pro; the two chains are compared side by side.
02 / Molecular architecture
A closer look at the chain.
Thr–Lys–Pro–Arg corresponds to the tuftsin segment, followed by Pro–Gly–Pro. The extension is part of the same seven-residue molecule, not a separate blended ingredient.
- 7 amino acids
- Tuftsin-related segment
- Pro–Gly–Pro extension
- 1Thr
- 2Lys
- 3Pro
- 4Arg
- 5Pro
- 6Gly
- 7Pro
Reference information: [1][2][3]. Actual lot identity must be verified separately.
Two sequence regions in one molecule.
The TKPR region relates to tuftsin, and PGP denotes the Pro–Gly–Pro extension. Reading TKPRPGP as one continuous sequence distinguishes Selank from a mixture of the two fragments. The boundaries explain the design history without changing the fact that the reference is a single seven-residue chain.
A shared ending does not define the whole chain.
Selank and Semax both include Pro–Gly–Pro, but the residues preceding that ending differ. A matching sequence segment can be useful for structural comparison without establishing identical molecular identity. The complete backbone is the relevant unit when distinguishing the two references.
Structure and research references: [1]
03 / Read the evidence
Research & analytical context.
The chemical reference identifies the seven-residue chain and its acetate salt separately. The Pro–Gly–Pro extension is part of the peptide backbone; acetate is not an additional amino acid in that chain.
Read the references: [1][2][3].
The distinction that matters
Unmodified Selank and N-acetylated derivatives have different chemical identities. Confirm terminal modifications and salt form on the supplied material’s documentation.
04 / From reference to record
Know the lot, too.
A publication describes its own test material. Your lot’s certificate describes what was tested on that lot. Keep the compound name, batch number and reported methods together when reviewing a result.
Identity & composition
Check sequence or chemical form, terminal modifications, counterion and—where relevant—each blend component.
Analytical results
Read purity, content, sterility and endotoxin results as separate measurements. Only call a test passed when the actual report supports it.
Handling & storage notes
Lyophilized material: Store at −20°C; protect from light and moisture.
Follow the material-specific label and supporting storage documentation. These temperatures do not establish a shelf life.
How to store lyophilized peptides05 / Reference questions
A few details, explained.
Is Selank simply tuftsin under another name?
No. The reference includes the Pro–Gly–Pro extension as part of its chain. That extension is a structural distinction, not an optional ingredient in the name.
Do Selank and Semax have identical sequences?
No. Their first four residues differ. Sharing the PGP ending does not make the full seven-residue chains the same.
Read alongside the references: [1]
06 / Continue reading
Go to the source.
Each source is labeled by its type. External sources are not Pioneer batch certificates.