TB-500 Mechanism of Action: The Thymosin Beta-4 Fragment and Actin Binding
Research compounds for laboratory use only · not medical advice
How TB-500's conserved actin-binding (LKKTETQ) domain drives the cell-migration and tissue-repair mechanisms studied in research.
TB-500 is a synthetic thymosin beta-4 fragment — a short peptide built around the conserved LKKTETQ actin-binding domain that gives the full-length protein its biological activity. In research it is used as a fragment-level tool for studying actin dynamics and tissue-repair pathways.
The actin-binding domain
| Element | Role |
|---|---|
| LKKTETQ motif | Binds actin monomers — the conserved domain of thymosin beta-4 |
| Fragment design | Retains the actin-binding activity without the full 43-aa protein |
| Downstream effects studied | Cell migration, endothelial tubule formation, wound healing, anti-inflammatory signaling |
Actin dynamics sit under most cell-migration and tissue-repair research: cells must reorganize their cytoskeleton to migrate, proliferate and form new vessels. The LKKTETQ domain is the handle researchers use to probe those processes with a small, defined molecule.
Why a fragment instead of the full protein
Thymosin beta-4 is a 43-amino-acid protein. TB-500 (the fragment) is a smaller research tool that isolates the actin-binding axis. That design makes it practical for in vitro studies where a defined, lyophilized, batch-documented peptide is preferred over a full-length recombinant protein.
Research applications
- Cell migration and wound-healing models
- Endothelial cell tubule formation (angiogenesis-adjacent)
- Actin-dynamics studies
- Combined with BPC-157 in the popular BPC-157 + TB-500 blend for dual-pathway tissue-repair research
Reference data
CAS 885340-08-9 · C212H350N56O78S1 · MW 4963.4 · 99.3% purity · 5 mg lyophilized vial
Store at -20°C, reconstitute with bacteriostatic water — see TB-500 reconstitution math and BPC-157 vs TB-500.
Last updated September 9, 2026
FAQ
Frequently asked questions
What is TB-500?
TB-500 is a synthetic fragment of thymosin beta-4 (TB-4) built around the conserved actin-binding LKKTETQ domain.
What is TB-500's molecular weight?
4963.4 g/mol (C212H350N56O78S1); it ships as a lyophilized 5 mg research vial.
How does TB-500's mechanism relate to actin?
The LKKTETQ sequence binds actin monomers, which is central to the cell-migration, endothelial tubule-formation and wound-healing research models.
Is TB-500 approved for human use?
No. It is a research peptide for laboratory use only, supplied lyophilized with batch documentation.
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