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Peptide identity index

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.

TB-500

889.02 Da

BPC-157

137525-51-0

Not the same molecule

Fifteen residues versus seven. Often ordered together, never interchangeable.

TB-500

View specs

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.

CAS
Not assigned to this listing
Formula
Catalog mass
Sequence avg
889.02 Da
Monoisotopic
888.4916 Da
Sequence
Ac-Leu-Lys-Lys-Thr-Glu-Thr-Gln

Expected ions

[M+H]+

889.4989

[M+2H]2+

445.2531

[M+3H]3+

297.1711

Often confused with

How the index decides

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.