Description
TB-500 (Thymosin Beta-4 Fragment / Fequesetide)
Intended for laboratory research purposes only. Not for human consumption
TB-500 is a synthetic heptapeptide corresponding to the N-acetylated active fragment (amino acids 17–23) of thymosin beta-4 (Tβ4), a naturally occurring actin-sequestering protein.
Key Chemical Details:
- CAS Number: 885340-08-9
- Molecular Formula: C₃₈H₆₈N₁₀O₁₄
- Molecular Weight: 889.0–889.02 g/mol (commonly listed as 889.018; exact monoisotopic mass ≈888.50 Da)
- Amino Acid Sequence (one-letter code): Ac-LKKTETQ (N-acetylated; Ac = acetyl group)
- Full sequence (three-letter code): Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln
- N-terminal: Acetylated Leucine (Ac-Leu); C-terminal: Glutamine (Gln)
- IUPAC/Full Chemical Name: (2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S,3R)-2-[[(2S)-2-[[(2S)-2-[[(2S)-2-acetamido-4-methylpentanoyl]amino]-6-aminohexanoyl]amino]-6-aminohexanoyl]amino]-3-hydroxybutanoyl]amino]-4-carboxybutanoyl]amino]-3-hydroxybutanoyl]amino]-5-amino-5-oxopentanoic acid (or similar variants reflecting the linear heptapeptide with N-acetylation)
- PubChem CID: 62707662
- Appearance (typical research grade): White to off-white lyophilized powder
- Solubility: Readily soluble in water (e.g., ≥1 mg/mL) and aqueous buffers
- Storage: Typically -20°C (as lyophilized powder for stability); avoid repeated freeze-thaw cycles and light/moisture exposure
- Other Properties:
- Contains the conserved actin-binding motif (LKKTET) critical for Tβ4-like activity
- Amphiphilic with charged (Lys, Glu) and polar (Thr, Gln) residues
- High polarity from multiple basic (Lys) and acidic (Glu) side chains
- Sensitive to proteases (shorter fragment offers some stability), heat, light, and extreme pH
Disclaimers:
- Strictly for qualified laboratory research professionals.
- Not FDA-approved; no therapeutic, diagnostic, or human-use applications
- Purity typically ≥98–99% (HPLC); batch-specific third-party Certificates of Analysis (COAs) available for identity, purity, and contaminants.
- Handle according to standard lab safety protocols.
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