Actin-Sequestering Peptide / Thymic Hormone
Thymosin Beta-4 (TB-4, Tβ4) Research Peptide
Thymosin Beta-4 (Tβ4, TB-4) is an endogenous 44-amino acid peptide that is one of the most abundant peptides in eukaryotic cells. It functions primarily as an actin-sequestering protein — binding G-actin monomers and regulating the dynamic equilibrium between monomeric and filamentous actin — and is studied in the contexts of cytoskeletal regulation, cell migration, angiogenesis, and tissue remodeling.
Compound identity
- Name
- Thymosin Beta-4
- Class
- Actin-Sequestering Peptide / Thymic Hormone
- CAS number
- 77591-33-4
- Molecular formula
- C₂₁₂H₃₅₀N₅₆O₇₈S
- Also known as
- TB-4, Tβ4, Thymosin β4, TB4
- Sequence
- Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser (44 aa; N-terminal Ac; MW ~4963 Da)
Research context
Thymosin Beta-4 (CAS 77591-33-4, MW ~4963 Da, C₂₁₂H₃₅₀N₅₆O₇₈S) was originally isolated from thymic tissue by Goldstein and colleagues but is now understood to be ubiquitously expressed in essentially all nucleated mammalian cells, with particularly high concentrations in platelets and white blood cells. The peptide consists of 44 amino acid residues with an N-terminal acetylation (Ac-Ser). Its primary structural domain — the conserved LKKTET actin-binding motif (residues 17–23, often cited as the Wasp Homology 2 / WH2 domain) — mediates sequestration of monomeric (G-actin) and prevention of F-actin polymerization. This sequestration activity places Tβ4 at the center of cytoskeletal dynamics in migrating and remodeling cells.
Research into Thymosin Beta-4 has identified multiple downstream effects beyond its canonical actin-sequestering role. Studies in preclinical wound-healing models — particularly work by Malinda et al., Philp et al., and the Bhattacharyya lab — examined Tβ4's effects on keratinocyte migration, corneal healing, and angiogenic factor expression. The peptide has been investigated in cardiac research (Bock-Marquette et al., Nature, 2004, reported Tβ4 promotion of cardiac progenitor cell survival and differentiation in murine models), hair follicle biology (research examining dermal papilla cell activation), and neurological contexts (oligodendrocyte and neural progenitor work in demyelination models). An important distinction: Thymosin Beta-4 is a distinct molecule from TB-500, which is a synthetic peptide corresponding to the active LKKTET fragment of Tβ4 (approximately residues 17–23, commercially designated TB-500 though the exact fragment definition varies). TB-4 is the full 44-aa native endogenous peptide.
As a research reagent, Thymosin Beta-4 is used in cytoskeletal biology, wound-healing and tissue-remodeling assays, angiogenesis research, and studies of actin dynamics. DMV Research supplies Tβ4 as a lyophilized peptide with per-batch Certificate of Analysis confirming identity by mass spectrometry and purity ≥99% by HPLC.
Frequently asked questions
What is Thymosin Beta-4 (TB-4)?+
Thymosin Beta-4 (Tβ4, CAS 77591-33-4) is an endogenous 44-amino acid N-terminally acetylated peptide expressed in virtually all nucleated mammalian cells. It functions as an actin-sequestering protein — binding monomeric G-actin and modulating cytoskeletal dynamics via its LKKTET WH2 domain. It is studied in tissue remodeling, wound healing, angiogenesis, and cell migration research.
What is the difference between Thymosin Beta-4 (TB-4) and TB-500?+
TB-500 is a commercial designation for a synthetic fragment of Thymosin Beta-4, generally corresponding to the active actin-binding LKKTET hexapeptide region (approximately residues 17–23 of Tβ4), though commercial TB-500 products may represent slightly different fragment boundaries. Thymosin Beta-4 (TB-4) is the full-length 44-amino acid endogenous peptide. The two have different molecular weights, different CAS numbers, and are studied as distinct research reagents, though both involve the actin-sequestering WH2 domain. TB-500 is already available in our research catalog; TB-4 represents the full-length native sequence.
Is Thymosin Beta-4 the same as Thymosin Alpha-1?+
No. Thymosin Alpha-1 (Tα1, CAS 62304-98-7) and Thymosin Beta-4 (Tβ4, CAS 77591-33-4) are distinct peptides with unrelated sequences and different biological roles. Both are named 'thymosin' because they were originally isolated from thymic tissue, but the naming reflects co-isolation, not structural or functional similarity. Tα1 is a 28-amino acid N-acetylated peptide studied in the context of immune modulation; Tβ4 is a 44-amino acid peptide studied for actin dynamics and tissue remodeling. Both are available in the DMV Research catalog.
Is Thymosin Beta-4 approved for human use?+
No. Thymosin Beta-4 is not FDA-approved for any indication. Clinical trials have investigated Tβ4 in specific wound-healing and cardiac contexts, but it has not received market approval. As supplied by DMV Research, it is for in-vitro and pre-clinical laboratory research purposes only. Not for human consumption.
Research use only
All products are intended for laboratory and research use only (RUO) and are not for human consumption, ingestion, or any in-vivo use.
The statements on this page have not been evaluated by the FDA. Thymosin Beta-4 is not intended to diagnose, treat, cure, or prevent any disease. Content is provided for laboratory research reference only.