TB-500

TB-500 is a synthetic analogue of Thymosin Beta-4 (Tβ4), an endogenous 43-amino acid peptide encoded by the TMSB4X gene. It is the most abundant member of the beta-thymosin family and functions as the principal actin-sequestering molecule in most eukaryotic cell types. Intracellular concentrations can reach up to 0.5 mM, reflecting its fundamental role in cytoskeletal regulation.

The peptide forms a 1:1 complex with G-actin (globular actin), opposing polymerization into F-actin (filamentous actin) and effectively buffering the monomeric actin pool. The conserved LKKTET motif at positions 17–22 is frequently cited as the primary actin-binding domain, though crystallographic modeling shows that essentially the entire length of the sequence interacts with actin in the complex. TB-500 does not bind to the extracellular matrix and has a low molecular weight, allowing it to travel through tissues efficiently.

Research Applications

• Actin polymerization dynamics and cytoskeletal remodeling studies
• Cell migration, morphology, and motility assays
• Angiogenesis research — identified as a gene upregulated 4–6 fold during early blood vessel formation
• Epicardial progenitor cell activation and cardiac remodeling models
• Anti-inflammatory pathway investigation (oxidized Tβ4 sulfoxide derivative)
• Wound fluid composition analysis and extracellular matrix signaling

Published Research Context

Thymosin Beta-4 was originally isolated from calf thymus and was the second peptide from Thymosin Fraction 5 to be fully sequenced and synthesized. Its role extends well beyond immune function: research at multiple institutions has demonstrated diverse effects in tissue regeneration models. Phase 2 clinical trials in patients with pressure ulcers, venous ulcers, and epidermolysis bullosa showed accelerated repair rates with favorable safety profiles. Notably, Glasgow University researchers (1999) identified the Tβ4 sulfoxide derivative as having multiple anti-inflammatory effects on neutrophils, including reduced adhesion to endothelial cells. The peptide is highly conserved across mammalian species, underscoring its fundamental biological significance.

Specifications

• Molecular Formula: C212H350N56O78S
• Molecular Weight: 4,963 g/mol
• Sequence Length: 43 amino acids
• Gene: TMSB4X
• Key Motif: LKKTET (positions 17–22)
• Form: White lyophilized powder
• Storage: Lyophilized, −20°C, desiccated
• Purity: ≥98% by HPLC

⚠ For in-vitro research use only. Not for human consumption. Not FDA approved. Certificate of Analysis included with every order.

🔬 Research Reference: TB-500 — Compound Reference & Research Data | Certificate of Analysis (Lot 2603)