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The peptide identity index tells you whether two names used for research peptides refer to the same molecule. Look up a catalog name, a CAS number, or an alias. Compare a second name when a vial, a paper, or a COA uses a different label.
Mass values computed from sequence are for checking an HPLC-MS report. This page does not calculate reconstitution volumes or human doses. Pair it with a lot-linked Certificate of Analysis and the 12-point COA audit.
Thymosin beta-4
77591-33-4
TB-500
889.02 Da
Fragment versus the 43-residue protein. Same family, not the same molecule.
Reference identity
Thymosin beta-4
Full-length protein, about 4,963 Da. Material sold as TB-500 is a short N-acetylated fragment of this sequence, not the protein itself.
No sequence-derived ions for this entry. Compare the catalog mass to the COA report.
Often confused with
Peptide
TB-500
Trade name for the N-acetylated 17-23 fragment of thymosin beta-4 (Ac-LKKTETQ). CAS 77591-33-4 and the ~4,963 Da mass belong to the full-length protein, not this heptapeptide.
Expected ions
[M+H]+
889.4989
[M+2H]2+
445.2531
[M+3H]3+
297.1711
Often confused with
Catalog CAS, formula, and sequence come from Tetrava lot identity tables. Monoisotopic mass and expected ions are calculated only when the sequence parses as standard residues plus common caps (acetyl, amide, Aib, Nle, pGlu). Heavily modified GLP-1 analogs stay as catalog text.
TB-500 is the main trap. Supplier tables often reuse the CAS and 4,963 Da mass of full-length thymosin beta-4 on a vial whose sequence is Ac-LKKTETQ. This index splits those identities on purpose.
Research use only. Not for human or veterinary consumption.
