CAS numbers and PubChem for peptides.
Two identifiers follow a peptide through catalogs, lab reports and papers: the CAS Registry Number and the PubChem Compound ID. They look like serial numbers, and they are, but they identify a specific chemical entity, so a salt, a cation and a free peptide can each carry their own. Here is what each number means, why some peptides have more than one and the numbers for the compounds in the Helion catalog.
One number per substance.
The Chemical Abstracts Service assigns a registry number to each distinct substance in its index, written as up to seven digits, two digits and a check digit, such as 137525-51-0 for BPC-157. The number carries no chemical information itself; it is a key into the CAS database. Because a salt is a different substance from the free peptide, the acetate of a peptide can have its own number, which is the most common reason two suppliers quote different CAS numbers for what is chemically the same peptide. Larazotide, for example, is 258818-34-7 as the free peptide and 881851-50-9 as the acetate.
One record per structure.
PubChem, run by the US National Library of Medicine, assigns a Compound ID to each unique structure deposited by its contributors and publishes the formula, computed mass and synonyms for each. A CID can be checked by anyone in a browser, which makes it the more useful of the two for verifying what a label claims: open the record, compare the formula and molecular weight with the product page and the lab report. Some peptides have a free-peptide record and an acetate record; some have records drawn with a wrong stereocenter or a missing cap, which is why the Helion pages note which CID they match. SNAP-8 is one example, where the default record differs from the correct one.
Identifiers for Helion compounds.
| BPC-157 | CAS 137525-51-0; PubChem CID 9941957 |
|---|---|
| SS-31 (elamipretide) | CAS 736992-21-5 |
| GHK-Cu | CAS 89030-95-5 (free GHK: 49557-75-7) |
| MOTS-c | CAS 1627580-64-6; PubChem CID 146675088 |
| Tesamorelin | CAS 218949-48-5; PubChem CID 16137828 |
| Sermorelin | CAS 86168-78-7; PubChem CID 16132413 (acetate 16132412) |
| Ipamorelin | CAS 170851-70-4; PubChem CID 9831659 |
| AOD-9604 | CAS 221231-10-3; PubChem CID 71300630 |
| SNAP-8 | CAS 868844-74-0; PubChem CID 76283482 |
| DSIP | CAS 62568-57-4; PubChem CID 68816 |
Each compound page in the research library carries the identifiers with a link to the PubChem record it was checked against.
Salts, stereochemistry and trade names.
Three situations produce conflicting identifiers. A supplier quotes the acetate's number while another quotes the free peptide's. A PubChem record was deposited with a stereocenter or cap different from the material actually sold, so its mass is off by a few daltons. Or a trade name covers more than one molecule, as with CJC-1295, where the DAC and no-DAC forms are different substances with different masses; CJC-1295 DAC vs no DAC works through that case. In each situation the sequence, formula and mass on the lab report settle what is in the vial, not the registry number.
Nothing about the vial.
A CAS number or CID identifies a structure, not a batch. It says nothing about purity, content, endotoxin or whether the vial labeled with it actually contains that structure. Those come from a Certificate of Analysis for the lot, verified with the lab that issued it. The identifiers are the reference the report is checked against, which is their whole job.
Identifiers on every page, reports on every lot.
Every Helion compound page lists CAS and PubChem identifiers with the sequence, formula and mass, and every lot has a third-party report in the COA Portal to check against them.
Specs and storage by compound.
Questions (6)
What is a CAS number for a peptide?
A registry number from the Chemical Abstracts Service that identifies one specific substance; the free peptide and its salts can each have their own.
What is a PubChem CID?
The Compound ID of a structure's record in PubChem, the US National Library of Medicine's chemical database, which publishes the formula, mass and synonyms for that structure.
Why do two suppliers list different CAS numbers for the same peptide?
Usually one quotes the free peptide and the other the acetate salt, which are different registry entries for the same peptide.
What is the CAS number of BPC-157?
137525-51-0; its PubChem CID is 9941957.
What is the CAS number of GHK-Cu?
89030-95-5 for the copper complex; the free tripeptide GHK is 49557-75-7.
Does a CAS number prove what is in a vial?
No. It identifies the intended structure. What is in the vial is shown by the lot's lab report.
Published studies (1)
Citations from PubMed for reference. They describe the compound in the literature, not any Helion lot, and nothing here is guidance on use.