Purity
98.7%
Fill
5 mg
Vial
3 mL
Lot
GPB-4488
Repair · CAS 77591-33-4
TB-500
Thymosin β4 Fragment
A 43-residue actin-sequestering fragment. Long chains are unforgiving to synthesise — this one gets a double-coupling protocol at every hindered residue.
At 43 residues, TB-500 sits at the point where stepwise synthesis starts fighting back: aggregation on resin, deletion sequences, and methionine oxidation are all live risks. We run double couplings from residue 18 onward, cap after every step so truncations stay separable, and hold the cleavage cocktail under nitrogen to keep the single methionine reduced. Purification is a two-pass job — a preparative cut followed by a shallow analytical-grade polish — and any lot that shows oxidised methionine above 0.5% by MS is rejected outright rather than blended down.
Primary sequence
Physical data
- Molecular formula
- C₂₁₂H₃₅₀N₅₆O₇₈S
- Molecular weight
- 4963.44 g/mol
- CAS number
- 77591-33-4
- Appearance
- White lyophilised powder
- Solubility
- Soluble in sterile water to 10 mg/mL
- Storage
- Lyophilised: −20 °C, desiccated
Certificate of analysis
Lot GPB-4488| RP-HPLC purity | 98.7% area @ 214 nm |
|---|---|
| Identity (ESI-MS) | 4963.8 observed, 4963.4 expected |
| Met sulfoxide | 0.31% |
| Net peptide content | 79.8% |
| Water (Karl Fischer) | 4.6% |
| Bacterial endotoxin | < 0.25 EU/mg (LAL) |
Handling
- Protect from oxygen — do not leave the vial uncapped after piercing.
- Reconstitute slowly down the vial wall; do not shake.
- Stable ~14 days at 2–8 °C once in solution.
For laboratory research use only. Not for human or veterinary consumption, diagnostic or therapeutic use. Supplied to qualified researchers at institutional addresses.