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Sequence & Structure

TB-500 Sequence, Molecular Weight & Chemical Identity

3 min read•Published 2025-11-02•Quality Peptide USA Research

TB-500 is a synthetic version of the active 17-amino-acid region of thymosin beta-4 (Tβ4), a naturally occurring polypeptide present in nearly all human and animal cells. TB-500 is widely used in laboratory research focused on actin sequestration, cell migration, and tissue regeneration.. This guide covers sequence & structure for TB-500 — written for laboratory researchers sourcing US-synthesized peptides from Quality Peptide USA.

Primary Sequence

The primary sequence of TB-500 is recorded as: Ac-Ser-Asp-Lys-Pro-Asp-Met-Ala-Glu-Ile-Glu-Lys-Phe-Asp-Lys-Ser-Lys-Leu-Lys-Lys-Thr-Glu-Thr-Gln-Glu-Lys-Asn-Pro-Leu-Pro-Ser-Lys-Glu-Thr-Ile-Glu-Gln-Glu-Lys-Gln-Ala-Gly-Glu-Ser-OH. Sequence integrity is verified during release testing using analytical reverse-phase HPLC compared against a reference standard, with mass spectrometry confirming the expected molecular ion.

Molecular Formula and Weight

TB-500 carries the molecular formula C212H350N56O78S and a calculated monoisotopic weight of approximately ≈ 4963 g/mol. These values are essential for accurate molar-concentration calculations during reconstitution and for normalizing dose curves across studies.

Identifiers and Synonyms

CAS Registry: 77591-33-4. Common synonyms include Thymosin Beta-4 Fragment, TMSB4X. When searching publications, querying both the common and chemical names typically surfaces the broadest body of work.

Structural Notes for Researchers

TB-500 is supplied as a lyophilized solid with a white to off-white appearance. Researchers should reconstitute in sterile bacteriostatic water unless their assay calls for a specific buffer (e.g., 0.1% acetic acid for hydrophobic peptides). Quality Peptide USA publishes the full chemical-identity card on every product page so that incoming-QC checks can be performed against a known reference.

Research Use Only

All content is for laboratory and in-vitro research contexts only. Not intended to diagnose, treat, or prevent any condition. Not for human or veterinary consumption.

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