Key findings
- The two sequences are different molecules. One is an adrenocorticotropic hormone fragment analogue whose binding was measured in rat basal forebrain membranes; the other is a tuftsin derived sequence that acts on tritiated GABA binding in isolated brain cell membranes. [1][2]
- A study that exposed mouse embryonic stem cells to both peptides reported different outcomes for each, with one raising survival under serum deprivation and the other lowering the proportion of GABA positive neurons, so the two are not interchangeable in the same assay. [3]
- Liquid chromatography with tandem mass spectrometry identified both peptides in seized preparations, which is the kind of method that can confirm the identity of each constituent in a combined listing. [4]
Identity and structure
- Components
- Met-Glu-His-Phe-Pro-Gly-Pro and Thr-Lys-Pro-Arg-Pro-Gly-Pro, two distinct heptapeptides [1][2]
- Composition
- The amount of each constituent and the total fill come from the lot documentation for the supplied material and are not established by any cited publication
- Identity confirmation
- Both sequences are separable and identifiable by liquid chromatography with tandem mass spectrometry, validated in several matrices [4]
- Form as supplied
- Sterile lyophilized powder
Mechanism as studied
The two components are studied through different assays. For the first sequence the cited work reports specific, calcium dependent binding in rat basal forebrain membranes together with a rise in brain-derived neurotrophic factor protein in that region. For the second the cited work reports positive allosteric modulation of tritiated GABA binding in isolated brain cell plasma membranes. [1][2]
No cited publication measures the two peptides applied together. The one study in the component set that exposed cells to both did so as separate treatment arms, and its authors report separate results for each, so nothing here describes an interaction between them. [3]
Research findings
Ex vivo
- System
- Cell membranes isolated from rat basal forebrain, and rat brain tissue, testing the first component alone
- Measured
- Binding of tritium-labelled peptide, its reversibility and calcium requirement, its dissociation constant and maximum binding capacity, and brain-derived neurotrophic factor protein
- Reported
- Binding was time dependent, specific and reversible and required calcium ions, with a dissociation constant of 2.4 nM and a maximum binding capacity of 33.5 fmol per mg protein. Brain-derived neurotrophic factor protein rose in basal forebrain at 3 h and did not rise in cerebellum. [1]
Ex vivo
- System
- Isolated plasma membranes from brain cells, testing the second component alone with its purity confirmed by HPLC
- Measured
- Tritiated GABA binding by the radioligand receptor method, alone and jointly with benzodiazepines, diazepam and olanzapine
- Reported
- The peptide acted as a positive allosteric modulator of tritiated GABA binding. Its joint action with benzodiazepines was not cumulative, and it blocked the modulatory activity of diazepam and olanzapine, which the authors read as partly overlapping but non-identical sites. [2]
In vitro
- System
- Mouse embryonic stem cells and their derivatives, with both components present in the study as separate treatment arms alongside thyroliberin and several glyproline peptides, never as a mixture
- Measured
- Proliferative activity, survival under serum deprivation, formation of neuronal precursors, differentiation into mature neurons and the proportion of GABA positive neurons
- Reported
- The first component raised the survival rate of the cells under serum deprivation. The second had an insignificant effect on differentiation into mature neurons and lowered the proportion of GABA positive neurons by 61 percent relative to control. The authors report the two separately and do not test them together. [3]
Analytical
- System
- Two seized pharmaceutical preparations and a panel of 10 polypeptides sold online, which included both components
- Measured
- Identity of each polypeptide by a combined liquid chromatography tandem mass spectrometry method, validated in different matrices under ISO 17025
- Reported
- Both sequences were identified in the seized preparations. The authors note that neither peptide had completed a clinical trial and that such material circulates both as lyophilized powder and in ready-made preparations. [4]
Handling for in-vitro work
- Purity check in cited work
- Peptide purity was confirmed by HPLC before the membrane binding experiments on the second component [2]
- Storage
- Lyophilized at -20 °C, dark and dry; reconstituted aliquots kept cold and used promptly
Open questions
- No cited study characterizes the mixture, so its composition, stability and any interaction between the two peptides are open.
- A combined mass on a label does not give the amount of either constituent; the split has to come from the lot documentation.
- The two components were characterized in different assay systems, so the cited results cannot be compared with each other directly.
- Whether the two sequences remain separable and stable in a single reconstituted vial is not addressed by any cited publication.
Clinical literature exists for each component separately and concerns finished formulations; it is out of scope for a research material profile and says nothing about this combination.
Lot records
Check the record for the exact material you order. A published paper and a batch certificate answer different questions.
No published lot is available for this exact compound name.
Read a certificate of analysis ↗References
- Dolotov OV, Karpenko EA, Seredenina TS, et al. Semax, an analogue of adrenocorticotropin (4-10), binds specifically and increases levels of brain-derived neurotrophic factor protein in rat basal forebrain. Journal of neurochemistry. 2006.
- Vyunova TV, Andreeva L, Shevchenko K, et al. Peptide-based Anxiolytics: The Molecular Aspects of Heptapeptide Selank Biological Activity. Protein and peptide letters. 2018.
- Kobylyanskii AG, Zolotarev YA, Andreeva LA, et al. Studying the Toxic Effects of Some Biologically Active Peptides on the Model of Mouse Embryonic Stem Cells. Bulletin of experimental biology and medicine. 2017.
- Vanhee C, Francotte A, Janvier S, et al. The occurrence of putative cognitive enhancing research peptides in seized pharmaceutical preparations: An incentive for controlling agencies to prepare for future encounters of the kind. Drug testing and analysis. 2020.
Publication records fetched from PubMed on 2026-09-20. Profile text reviewed 2026-09-20.