Introduction to TB-500
TB-500 is a synthetic 7-amino acid peptide corresponding to the active region of thymosin beta-4 (Tβ4), the most abundant intracellular peptide in mammalian cells (~0.5% of cytoplasmic protein). TB-500 sequence (Ac-LKKTETQ) represents the actin-binding domain responsible for the majority of Tβ4's biological activity in tissue repair research.
Thymosin Beta-4: Biological Context
Full-length Tβ4 (43 AA, ~4.9 kDa) is expressed in virtually all cells and secreted in response to tissue injury. It serves as the primary G-actin sequestering protein, maintaining a pool of monomeric actin for rapid cytoskeletal remodeling.
Molecular Properties (TB-500 Active Fragment)
- Sequence: Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln
- MW: ~2,100 Da
- Actin binding: Direct G-actin binding via KLKKTET domain
- Distribution: Secreted; circulates in blood and lymph
- Half-life: Estimated hours; weekly dosing used in most research
Core Mechanisms
Actin Sequestration → Cell Migration
- Binds G-actin, modulating F-actin/G-actin equilibrium
- Facilitates lamellipodia formation for directed cell migration
- Critical for wound closure, satellite cell activation, angiogenesis
Anti-Inflammation
- NF-κB pathway inhibition
- M1→M2 macrophage polarization
- Promotes inflammation resolution (efferocytosis)
Angiogenesis
- VEGF receptor upregulation on endothelial cells
- Endothelial cell migration and tube formation
- Capillary density increases in ischemic models
Research Data Summary
| Model | Key Finding |
|-------|-------------|
| Muscle crush | Accelerated satellite cell activation, faster recovery |
| MI (cardiac) | 20–35% infarct size reduction, preserved EF |
| Wound healing | 3–5x faster closure in scratch assays |
| Tendon | Increased collagen synthesis and tenocyte migration |
| Neurological | Some evidence for peripheral nerve regeneration |
Reconstitution Protocol
10mg vial:
- 2mg/mL: Add 5mL BAC water
- 5mg/mL: Add 2mL BAC water
Swirl gently to dissolve (60–90 sec). Store at 2–8°C. Use within 4–8 weeks.
TB-500 10mg from our verified supplier — research-grade, for laboratory use.