Compound Guide
TB-500 (Thymosin Beta-4 Fragment) Research — Actin Regulation & Tissue Repair
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TB-500 (Thymosin Beta-4 fragment): actin sequestration and cell migration. Sanders PNAS 1992 and Bock-Marquette Nature 2004 founding citations.
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TB-500 is a synthetic 7-amino-acid peptide (Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln; Ac-LKKTETQ) corresponding to residues 17–23 of Thymosin Beta-4 (Tβ4) — the actin-binding domain of the full 43-amino-acid endogenous protein. TB-500 and full-length Tβ4 are related but structurally distinct. Clinical trial data — including ophthalmic (RGN-259) and cardiac trials — use full-length Tβ4, not the TB-500 fragment. Conclusions from those trials do not automatically transfer to TB-500.
Actin Sequestration Mechanism
TB-500 sequesters G-actin (globular, monomeric actin), maintaining a pool available for rapid polymerization when cells need to migrate. This directly influences lamellipodia and filopodia formation at the cell's leading edge.
The actin-sequestering function of Tβ4 was definitively established by Sanders MC, Goldstein AL, Wang YL (Proc Natl Acad Sci USA. 1992;89(10):4678–4682, PMID: 1584803), demonstrating Tβ4 binds G-actin in 1:1 stoichiometry and prevents polymerization in living cells.
Cardiac Repair — Nature (2004)
Bock-Marquette I, Saxena A, White MD, Dimaio JM, Srivastava D (Nature. 2004;432(7016):466–472, PMID: 15565145) demonstrated that systemic Tβ4 administration after experimental myocardial infarction in mice improved cardiac function, reduced scar size, and enhanced neovascularization via integrin-linked kinase (ILK) activation.
Complementarity with BPC-157
BPC-157 drives angiogenesis via VEGFR2/NO pathways; TB-500 drives cell migration via actin regulation. These represent two distinct, complementary phases of tissue repair — the mechanistic rationale for studying them together.
Key References
- Sanders MC, Goldstein AL, Wang YL. Thymosin beta 4 is a potent regulator of actin polymerization. Proc Natl Acad Sci USA. 1992;89(10):4678–4682. PMID: 1584803.
- Bock-Marquette I, et al. Thymosin beta4 activates integrin-linked kinase and promotes cardiac cell migration and repair. Nature. 2004;432(7016):466–472. PMID: 15565145.
- Goldstein AL, Hannappel E, Kleinman HK. Thymosin beta4: actin-sequestering protein moonlights to repair injured tissues. Trends Mol Med. 2005;11(9):421–429.
For educational and research reference only. TB-500 is supplied for in-vitro laboratory research use only. Not for human consumption.
Compounds Referenced in This Article
For in-vitro laboratory research use only
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This article is for informational and research purposes only. All compounds referenced are sold strictly for in-vitro laboratory research use and are not intended for human consumption, veterinary use, or clinical/diagnostic procedures. These statements have not been evaluated by the FDA. Avera Refined Wellness is a subsidiary of RDS 412 LLC.
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