TB-500 is the synthetic form of Thymosin Beta-4, a 43-amino acid actin-regulating peptide found in all human cells. Extensively studied for cell migration, tissue repair, and anti-fibrotic research.
TB-500 is the synthetic preparation of Thymosin Beta-4 (Tβ4), a highly conserved 43-amino acid peptide that is expressed ubiquitously in virtually all mammalian cells and tissues, with the notable exception of red blood cells. First isolated from calf thymus by Goldstein’s laboratory in the 1960s as part of the thymosin family, Tβ4 was subsequently identified as the most abundant intracellular G-actin (globular actin) sequestering peptide in eukaryotic cells, present at concentrations of 100-500 μM in the cytoplasm. Its primary physiological role is the maintenance of the cellular actin monomer pool, directly regulating the equilibrium between monomeric G-actin and polymerized F-actin filaments that form the structural basis of the cytoskeleton.
The mechanism of TB-500’s biological activity is multifaceted. The central actin-binding domain (residues 17-23, LKKTETQ) enables G-actin sequestration, which in turn regulates cytoskeletal dynamics necessary for cell migration, shape change, and wound response. The N-terminal tetrapeptide Ac-SDKP (residues 1-4), released by prolyl oligopeptidase enzymatic cleavage, functions as an independent bioactive molecule that has been extensively studied for anti-fibrotic and anti-inflammatory properties. Ac-SDKP inhibits collagen deposition by cardiac and renal fibroblasts and suppresses inflammatory cell recruitment. Additionally, the full-length peptide promotes upregulation of actin and other cytoskeletal proteins necessary for endothelial cell migration and tubule formation, contributing to new blood vessel development in research models.
The published research literature for Thymosin Beta-4 is extensive, spanning over 1,000 publications across PubMed. Key research application areas include cardiac repair models (post-ischemic cardiac function, cardiomyocyte survival), dermal wound healing (full-thickness excisional wound closure, burn models), corneal epithelial repair (corneal debridement healing, alkaline burn recovery), hair follicle biology (dermal papilla stem cell activation, follicle cycling), musculoskeletal repair (muscle contusion, tendon healing), and neurological repair models (peripheral nerve regeneration, CNS injury response). The peptide has also been studied for modulation of inflammatory cell phenotypes, including macrophage polarization from pro-inflammatory (M1) to anti-inflammatory (M2) states.
Landmark published studies include the discovery by Sosne et al. that Tβ4 promotes corneal wound healing and suppresses corneal inflammation, the demonstration by Bock-Marquette et al. (published in Nature) that Tβ4 activates the survival kinase Akt/PKB in cardiomyocytes following ischemic injury, and the identification of Ac-SDKP as an endogenous anti-fibrotic factor naturally regulated by angiotensin-converting enzyme (ACE). These foundational publications have been widely cited and independently replicated.
Supplied as a lyophilized powder with ≥99% purity confirmed by RP-HPLC and ESI-MS. Certificate of Analysis provided with each lot. Store at -20°C desiccated. Reconstitute with bacteriostatic water. For laboratory research purposes only.
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