Independent research-data planningEditorial and review policy
PHPeptide HarborResearch Data Harbor
Menu ▼
Peptide Harbor / Lab Notes

Entity-boundary dossier

How should TB-500 be distinguished from full-length thymosin beta-4?

A research dossier that fixes TB-500 to the reviewed N-acetylated heptapeptide entity and keeps it separate from full-length thymosin beta-4 records.

Reviewed by Peptide Harbor editorial reviewUpdated 2026-08-03Educational research-data guidance

Answer first

TB-500 should be named as the N-acetylated seven-residue peptide Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH. Full-length thymosin beta-4 has a different sequence, formula, mass, and evidence context, so the two names must never share one chemical ledger.

Reviewed Chemical LedgerTB-500
Molecular form representedN-acetylated heptapeptide represented by PubChem CID 62707662
CAS number
885340-08-9
Molecular formula
C38H68N10O14
Average molecular weight
889.0 g/mol average molecular weight
Exact mass
888.49164688 Da
Reviewed peptide designationAc-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH
Sequence representationIncludes stated terminal and modification notation
Ac-LKKTETQ-OH
Structural notes
  • N-terminal acetylation
Known Aliases / Code Names:TB-500TB500UNII-QHK6Z47GTG

Field-level sources

PubChem CID 62707662: TB-500

National Library of Medicine / PubChem · accessed 2026-08-03

Supports: name, molecularForm, cas, formula, weight, exactMass, sequence, peptideDesignation, modifications, aliases

Where this framework helps

  • Resolving TB-500 versus thymosin beta-4 naming conflicts
  • Building an expected-mass record for the acetylated heptapeptide
  • Reviewing whether a report and sample label describe the same entity

Limits to keep visible

  • The common name alone does not prove which entity a third-party file used.
  • This dossier does not transfer full-length thymosin beta-4 evidence to TB-500.
  • Recovery, injury, dosing, and human-use content is excluded.
01

Anchor TB-500 to a defined fragment

The reviewed PubChem compound lists the condensed sequence Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln-OH. The N-acetyl group and C-terminal acid are part of the expected molecular entity.

02

Keep the full-length record separate

Thymosin beta-4 is a much larger peptide with a different compound record. References about the full-length protein can provide terminology context but cannot populate TB-500 formula, mass, sequence, or sample conclusions.

03

Make identity evidence explicit

The packet should connect the sample label to the heptapeptide sequence, expected mass, analytical method, and observed data. A generic thymosin label is an unresolved identity gap.

Primary and official sources

References used for this page

Visible FAQ

Questions research teams ask

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

Not in this reviewed ledger. TB-500 is represented by an N-acetylated heptapeptide; full-length thymosin beta-4 is recorded separately and has a different molecular identity.

Why include Ac- and -OH in the sequence line?

They define the terminal chemistry used for the formula and mass record. Removing them describes a different expected form.

What should be flagged in an incoming report?

Flag any report that uses TB-500 and thymosin beta-4 interchangeably without a sequence, expected mass, or compound reference that resolves the entity.