Source comparison
Sequence and Molecular Weight: A Structural Comparison
Getting the structural facts right is the anchor of the whole tb-500 vs tb4 discussion. The following reflects what is documented for the endogenous protein, alongside the honest caveats for the market label. Length 43 amino acids Short peptide containing the
This comparison does not assign a generated winner or score.
- Getting the structural facts right is the anchor of the whole tb-500 vs tb4 discussion. The following reflects what is documented for the endogenous protein, alongside the honest caveats for the market label.
- Length
- 43 amino acids
- Short peptide containing the LKKTETQ motif (exact length varies by product/description)
- Approx. molecular weight
- ~4.9 kDa (~4963 Da)
- Substantially smaller if a true fragment; ~full weight if actually full-length Tβ4
- Key functional motif
- LKKTETQ actin-binding domain (residues ~17–23)
- Built around the same motif
- N-terminal feature
- Acetylated; can release Ac-SDKP on processing
- Fragment may not reproduce Ac-SDKP generation
- Verified commercial identity
- Defined for research-grade recombinant/synthetic Tβ4
- Not reliably verified across suppliers
- The single most important honesty point in this whole article lives in that table’s last row. The endogenous protein has a defined sequence and mass. A product labeled “TB-500” may match that protein, may be a smaller actin-binding fragment, or may vary between suppliers. The published, verifiable structural fact is about Thymosin Beta-4; the structure of any specific TB-500 vial is a claim on a label, not a fact confirmed in the peer-reviewed record. Our peptide research glossary defines the underlying terms — actin sequestration, angiogenesis, fragment, motif — for readers who want the vocabulary spelled out.