Synthetic β-thymosin-derived heptapeptide

TB-500

Also known as TB500 · TB4 fragment · Ac-LKKTETQ · N-acetyl thymosin β-4 (17-23)

TB-500 is the N-acetylated heptapeptide Ac-LKKTETQ derived from residues 17-23 of thymosin β-4, encompassing the conserved LKKTET actin-binding motif characteristic of WH2-domain peptides.

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ClassSynthetic β-thymosin-derived heptapeptide

Molecular weight~889.0 g/mol (free base; acetate salt form ~949.1 g/mol)

Molecular formulaC38H68N10O14 (free base); acetate salt C40H72N10O16 (PubChem CID 155977548)

CAS number885340-08-9

The overview

What is TB-500?

TB-500 is the N-acetylated heptapeptide Ac-LKKTETQ derived from residues 17-23 of thymosin β-4, encompassing the conserved LKKTET actin-binding motif characteristic of WH2-domain peptides. In cell-free and cultured-cell systems, parent thymosin β-4 functions as the principal intracellular G-actin (monomeric actin) sequestering peptide: it binds G-actin in a 1:1 complex (reported Kd in the sub-micromolar to low-micromolar range), inhibits nucleotide exchange, and holds actin in a polymerization-incompetent state, thereby buffering the pool of unpolymerized actin available for filament (F-actin) assembly. Mutational and NMR mapping studies localize the principal actin contacts to electrostatic interactions involving the LKKTET motif lysines and an N-terminal helix. At the signaling level, in-vitro models associate this actin-regulatory activity with modulation of cytoskeletal dynamics relevant to endothelial cell migration, tubule formation, and angiogenic sprouting. The framing here is receptor-independent cytoskeletal/biochemical regulation in laboratory models only.

In the research

Where TB-500 shows up

The areas researchers focus on with TB-500 - and why it has the science community paying attention.

In-vitro G-actin sequestration and actin-monomer buffering assays
Actin filament (F-actin) polymerization kinetics in cell-free systems
Cytoskeletal dynamics and cell-migration models (endothelial/fibroblast cultures)
Angiogenesis and endothelial tubule-formation in-vitro models
Structure-activity mapping of the LKKTET / WH2 actin-binding motif (NMR, mutational analysis)
Comparative β-thymosin family biochemistry

By the numbers

The facts that matter

Peptide identity / originSynthetic N-acetylated heptapeptide (Ac-LKKTETQ) corresponding to residues 17-23 of endogenous thymosin β-4, containing the conserved LKKTET actin-binding motif

CAS Registry Number885340-08-9

Molecular formula (free base)C38H68N10O14

Molecular weight (free base)~889.0 g/mol

Primary molecular mechanism (parent Tβ4)G-actin (monomeric actin) sequestration; holds actin in polymerization-incompetent state and inhibits nucleotide exchange

Actin-binding site localizationElectrostatic contacts involving LKKTET-motif lysines (e.g. Lys18) and an N-terminal helix region

Angiogenesis-relevant motif (in-vitro)The seven-amino-acid actin-binding motif of Tβ4 is required for angiogenic activity in endothelial cell models

To the molecule

Molecular specifications

Molecular formulaC38H68N10O14 (free base); acetate salt C40H72N10O16 (PubChem CID 155977548)

Molecular weight~889.0 g/mol (free base; acetate salt form ~949.1 g/mol)

CAS number885340-08-9

Amino-acid sequence

Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH (Ac-LKKTETQ); corresponds to residues 17-23 of thymosin β-4, containing the conserved LKKTET actin-binding motif

Sourced, not claimed

The science behind it

The peer-reviewed studies behind TB-500, linked so you can read them yourself.

Goldstein, A. L., et al. (2012). Thymosin beta 4: actin-sequestering peptide pathways in wound healing and tissue regeneration. Vitamins and Hormones.
DOI ↗
Smart, N., et al. (2011). Thymosin beta 4 induces adult myocardial regeneration and neovascularization. Nature.
DOI ↗

Straight answers

Questions, answered

Is TB-500 approved by the FDA?

No. TB-500 is not an FDA-approved drug. We supply it as a research-use-only reference compound, identity-verified for purity with a COA on every vial.

What class of compound is TB-500?

TB-500 is classified as: Synthetic β-thymosin-derived heptapeptide (N-acetylated actin-binding fragment); WH2-motif-containing actin-sequestering peptide.

What is the molecular weight of TB-500?

The molecular weight of TB-500 is ~889.0 g/mol (free base; acetate salt form ~949.1 g/mol), with a molecular formula of C38H68N10O14 (free base); acetate salt C40H72N10O16 (PubChem CID 155977548).

What is the CAS number for TB-500?

The CAS Registry Number for TB-500 is 885340-08-9.

What is the amino acid sequence of TB-500?

TB-500 has the sequence: Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH (Ac-LKKTETQ); corresponds to residues 17-23 of thymosin β-4, containing the conserved LKKTET actin-binding motif.

Available now

Get TB-500

Identity-verified, third-party tested, made in the USA, and traceable to its lot - with a scannable COA on every vial. For research use only.

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Go deeper

More on TB-500

MechanismTB-500 mechanism of action: receptor binding, signal transduction, and mRead →ResearchTB-500 research: peer-reviewed studies, in-vitro and preclinical model cRead →ReconstitutionHow TB-500 is reconstituted for in-vitro laboratory research: bacteriostRead →Half-LifeTB-500 pharmacokinetic, stability, degradation, and storage characteristRead →SpecsTB-500 molecular specifications: amino-acid sequence, molecular weight, Read →FAQAnswers to common research questions about TB-500: classification, strucRead →

Keep exploring

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For in-vitro laboratory research use only. Not for human or animal consumption. Bodily introduction into humans or animals is strictly prohibited by law. TB-500 is not a drug and is not intended to diagnose, treat, cure, or prevent any disease. These statements have not been evaluated by the FDA.

Complete the stack

Researchers often pair TB-500 with

BPC-157

Reciprocal of the canonical repair pairing - actin-driven migration co-investigated with cytoprotective signaling.

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GHK-Cu

Collagen-matrix remodeling research complements actin-regulated migration in the repair axis.

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GLOW Blend

TB-500 is a named component of the GLOW research stack - the pre-combined repair + dermal kit.

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