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TB-500 Pro research peptide vial and box
TB-500 - Pro
  1. TB-500 Pro research peptide vial and box
  2. TB-500 - Pro

TB-500 – Pro

Pro Series
Thymosin beta-4, a 43-amino-acid N-acetylated actin-sequestering peptide
CAS 77591-33-4C₂₁₂H₃₅₀N₅₆O₇₈SApproximately 4963 g/mol43 amino acidsLinear peptideLyophilized powder

Price range: $60.00 through $850.00

Ships from lot PLB-TB55-20260706-03 · 5 mg vial · 99% purity · pH Solutions Lab See the COA
Why the Pro Series costs more
  • Synthesized in the USA. Domestic ground and air only, no ocean freight.
  • Released only above 99% HPLC purity.
  • Its own lot and its own published certificate.
How the Pro Series is made and tested
Ships from Austin, TexasUnited States only
Tested by an outside labNever in-house
Every lot publishedIncluding rejected lots
Same-day dispatchOn orders before 2pm ET
SKU: N/A Category: Tags: ,
BATCH
VERIFICATION
LOT NUMBER
PLB-TB55-20260706-03
5 mg vial
IDENTITY
Supported by HPLC retention-time match to a certified reference standard (no mass spectrometry on this certificate)
CHROMATOGRAPHIC PURITY
99%
APPEARANCE
White to off-white lyophilized powder cake, free of visible particulates
Analytical characterization

Every result against its specification.

Lot PLB-TB55-20260706-03 · 5 mg vial · pH Solutions Lab · reported 23 July 2026 . The bar shows where the reported result falls against Astramide’s published release criterion. The notch marks the criterion.
Within criterion Above criterion Not on this COA
Test
Method
Criterion
Result
Result vs criterion
Status
Identity
HPLC retention time vs certified reference standard
Match to the labelled compound
Supported by HPLC retention-time match to a certified reference standard (no mass spectrometry on this certificate)
WITHIN SPEC
Chromatographic purity
HPLC (220 nm)
at or above 99.0%
99%
95 at or above 99.0% 100
WITHIN SPEC
Net content
—
Not reported on this certificate (fill conformance 300/300 vials at 5.00 mg target fill)
NOT REPORTED
Appearance
Visual
white lyophilized powder
White to off-white lyophilized powder cake, free of visible particulates
WITHIN SPEC
Microbial panel
qPCR
not detected
Pass, total aerobic count, Enterobacteriaceae and total yeast and mold not detected in 1 g
WITHIN SPEC
Mycotoxins
LC-MS
below limits
Not detected (aflatoxins B1, B2, G1, G2 and ochratoxin A)
WITHIN SPEC
Water activity
Water activity meter
below 0.65 aw
0.43 aw, pass
WITHIN SPEC
Residual solvents
GC headspace
within ICH Q3C limits
Below ICH Q3C Class 2/3 limits
WITHIN SPEC
Heavy metals
ICP-MS (USP <232>)
within USP limits
Below USP <232> limits
WITHIN SPEC
Endotoxin
LAL
—
Not reported on this certificate
NOT REPORTED
Values are reported per vial unless otherwise noted. Every figure here is taken from the batch Certificate of Analysis and nothing else.
Certificate of Analysis
TB-500 - Pro · Lot PLB-TB55-20260706-03 · 5 mg vial · Lab No. PLB-TB55-20260706-03
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Quick reference

How to read this report

Same six keys on every Astramide product page. Only the values change.
1Lot numberMatch it to the number printed on your vial. If they differ, this report is not for your vial.
2IdentityMass spectrometry confirms the molecule is the one on the label. It conforms or it does not. There is no partial result.
3Chromatographic purityThe share of the material that is the target peptide. A purity figure quoted without a method is not a purity figure.
4Net contentHow much peptide is in the vial, as measured by the laboratory. A different question from purity.
5EndotoxinMeasured against a ceiling, not a floor. Sensitivity differs by laboratory, so results are not compared across labs.
6Laboratory, method, dateWho ran it, on what instrument, and when. A report with no named laboratory or no date is not a report.
Molecular profile

TB-500 - Pro, in structural terms.

TB-500 - Pro molecular structure
Sequence
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 (Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES)
Molecular formula
C₂₁₂H₃₅₀N₅₆O₇₈S
Molecular weight
Approximately 4963 g/mol
CAS number
77591-33-4
Peptide length
43 amino acids
Structure type
Linear peptide
Parent sequence
Thymosin beta-4 (TMSB4X gene product)
Primary molecular target
Monomeric (G-) actin. Thymosin beta-4 binds actin monomers in a 1:1 complex and sequesters them from polymerization.
Physical form
Lyophilized powder
PubChem CID
16132341

Thymosin beta-4 is a 43-amino-acid linear peptide with an acetylated N-terminal serine. It belongs to the beta-thymosin family of small, highly charged actin-binding peptides and is largely unstructured in solution, adopting an extended conformation when bound to actin. The commercial name TB-500 is used here for synthetic full-length thymosin beta-4.

Research profile

Where TB-500 - Pro appears in the literature.

Cell Biology; Cytoskeletal Biology; Biochemistry; Structural Biology
Research applications
  • Published studies have used thymosin beta-4 in:
  • G-actin binding and sequestration studies
  • Actin polymerization studies
  • Beta-thymosin structure-function studies
  • Structural biology of actin complexes
Experimental systems
  • Purified actin in vitro
  • Cultured mammalian cell lines
  • Actin complexes with thymosin beta-4 constructs for X-ray crystallography
Specific assays
  • Actin polymerization assays
  • Actin monomer binding and sequestration assays
  • Amino acid sequencing
  • X-ray crystallography
Measured endpoints
  • Affinity for monomeric actin
  • Unpolymerized actin pool and polymerization kinetics
  • Ligand-actin contact residues
  • Primary amino acid sequence
Pcs

Single Vial, Pack of 10
Strength

5mg, 10mg
Mechanism and research context

What has been studied, and in what systems.

Thymosin beta-4 was isolated from thymus tissue, and its complete 43-residue sequence with an acetylated N-terminus was reported in 1981 (Low et al., 1981).

Biochemical studies later showed that thymosin beta-4 and its relative thymosin beta-10 both bind and sequester actin monomers, holding them in an unpolymerized pool (Yu et al., 1993).

A crystal structure of an actin complex with a thymosin beta-4 construct showed how the peptide stretches across the actin monomer and contacts both its ends, explaining how it blocks polymerization (Irobi et al., 2004). These studies place thymosin beta-4 in cytoskeletal and structural biology research.

These are published research systems. They do not describe approved clinical applications, and they do not establish efficacy or safety in humans.

Cited literature

Low TL et al., 1981. Complete amino acid sequence of bovine thymosin beta 4: a thymic hormone that induces terminal deoxynucleotidyl transferase activity in thymocyte populations. Proc Natl Acad Sci U S A. PMID 6940133. https://pubmed.ncbi.nlm.nih.gov/6940133/
Yu FX et al., 1993. Thymosin beta 10 and thymosin beta 4 are both actin monomer sequestering proteins. J Biol Chem. PMID 8416954. https://pubmed.ncbi.nlm.nih.gov/8416954/
Irobi E et al., 2004. Structural basis of actin sequestration by thymosin-beta4: implications for WH2 proteins. EMBO J. PMID 15329672. https://pubmed.ncbi.nlm.nih.gov/15329672/

Evidence level
Actin binding and sequestration by thymosin beta-4 are well characterised in biochemical and structural studies. Statements on this page describe experimental systems, not outcomes in humans.
Handling and storage
As supplied
Lyophilized powder in a sealed vial. Held in laboratory-rated freezers from arrival to shipment.
Storage
Store per the conditions printed on the vial label. Avoid heat, moisture and repeated temperature cycling.
Handling
For qualified professionals in controlled laboratory environments, following validated laboratory procedures.
Frequently asked questions

About this compound and its batch data.

What is TB-500 (thymosin beta-4)?

TB-500 Pro is synthetic full-length thymosin beta-4, a 43-amino-acid peptide with an acetylated N-terminal serine (Ac-SDKPDMAEIEKFDKSKLKKTETQEKNPLPSKETIEQEKQAGES). Its formula is C212H350N56O78S, its molecular weight is about 4963 g/mol and its CAS number is 77591-33-4. It is supplied as a lyophilized powder in a 5 mg vial. Sold for research use only.

What has thymosin beta-4 been examined for in published research?

Biochemical studies have shown that thymosin beta-4 binds actin monomers and holds them in an unpolymerized pool (Yu et al., 1993, PMID 8416954). A crystal structure later showed how the peptide stretches across the actin monomer to block polymerization (Irobi et al., 2004, PMID 15329672). This page describes laboratory research. Astramide makes no claim about outcomes in humans.

What purity does the current TB-500 Pro lot reach?

Lot PLB-TB55-20260706-03 returned 99% chromatographic purity by HPLC at 220 nm, reported by pH Solutions Lab on 23 July 2026 under certificate PLB-COA-TB55-20260706-03. Identity is supported by HPLC retention-time match to a certified reference standard; this certificate does not include mass spectrometry. The full certificate is published on this page.

How much TB-500 is in the vial?

The current certificate covers the 5 mg vial. It reports fill conformance of 300 out of 300 vials at the 5.00 mg target fill, but a measured net content result was not reported for lot PLB-TB55-20260706-03. The page shows that row as not reported rather than estimating a figure.

How should TB-500 be stored for research use?

Lyophilized thymosin beta-4 is stored at -20°C and protected from light. Once reconstituted, the solution is held at 2 to 8°C and used within 14 to 30 days. Repeated temperature cycling and exposure to moisture should be avoided, because both can affect peptide stability and the comparability of experimental results.

Is TB-500 the same as thymosin beta-4?

TB-500 is a commercial name, and it is used for more than one compound. Astramide TB-500 Pro is synthetic full-length thymosin beta-4, 43 amino acids and about 4963 g/mol. Some suppliers use the same name for a 7-residue fragment, Ac-LKKTETQ, which is a different compound with a molecular weight of about 889 g/mol. The certificate and molecular weight show which one a vial contains.

How is Astramide's TB-500 Pro tested?

Lot PLB-TB55-20260706-03 was tested by pH Solutions Lab, an independent ISO/IEC 17025:2017 accredited laboratory (PJLA #84351). The certificate reports purity by HPLC at 220 nm, appearance, fill conformance, a qPCR microbial panel, mycotoxins by LC-MS, water activity of 0.43 aw, residual solvents against ICH Q3C limits and elemental impurities against USP <232>. Results apply only to this lot.

What is the difference between TB-500 and TB-500 Pro?

TB-500 Pro is part of the Astramide Pro Series. It is American-made, synthesized in the USA, and moves by domestic ground and air only, with no ocean freight. It is released under its own lot, and only when HPLC purity measures at or above 99%. The results for each lot are published on this page. The standard TB-500 is released under separate lots with separate certificates.

Research use only

This product is intended strictly for in-vitro laboratory research conducted by qualified professionals. It is not intended for human or animal consumption, clinical use, or therapeutic application. The statements on this page have not been reviewed by the FDA. These research peptides are not intended to diagnose, treat, cure, or prevent any disease. Research Use Only.

COA library Every lot we have tested Search by batch number. Past lots stay published. How we test The analytical panel What each method measures and the criterion each lot must meet. Open Lab Send us your peptides Any vendor. Same lab. Your own Certificate of Analysis.
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Replacement or store creditOn approved claims. See refund policy.

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