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Compound reference

PT-141: CAS number, formula, molecular weight and sequence

PT-141 (Bremelanotide) is a cyclic heptapeptide melanocortin receptor agonist (lactam-bridged alpha-MSH analogue), CAS 189691-06-3, molecular formula C50H68N14O10, average molecular weight 1025.2 g/mol.

For Laboratory Research Use Only. Not For Human Consumption.

Chemical data

Name
PT-141
Synonyms
Bremelanotide · PT 141
CAS number
189691-06-3This is the free base; bremelanotide acetate is 1607799-13-2.
Molecular formula
C50H68N14O10
Average molecular weight
1025.2 g/mol
Monoisotopic mass
1024.5243 Da
Residues
7
Class
Cyclic heptapeptide melanocortin receptor agonist (lactam-bridged alpha-MSH analogue)
PubChem CID
9941379
Form supplied
Lyophilized powder
Purity specification
≥98% (HPLC)
Storage
Store lyophilized at -20°C; protect from light

Sequence

XDHfRWK

One-letter convention here: X = non-proteinogenic residue, lowercase = D-amino acid. Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH: N-acetyl-norleucine (X1); lactam bridge between the Asp2 side-chain carboxyl and the Lys7 side-chain amine (2->7); D-Phe4; C-terminal FREE ACID (the C-terminal-acid counterpart of melanotan II).

PT-141 molarity calculator

Pre-filled with the average molecular weight above. Change it if your lot is a salt form.

g/mol
mg
mL

Uses the formula weight you enter. For salt forms (acetate, TFA) use the salt's weight, and correct for net peptide content from the lot's certificate where it is reported.

Result

2.439 mM

2.5 mg/mL

References

Publications characterising this compound. Neupeptides makes no representation as to the findings, methods or applicability of the work below. The list is bibliographic and is not a claim about any product.

  1. Yuvaraaj VK, et al. Comprehensive characterization of bremelanotide acetate and its degradants by LC-HRMS/MS and predicting epimerization through computational modelling. Anal Methods. 2026. PMID 42485063 · doi:10.1039/d6ay01098a
  2. Zhang H, et al. Structural insights into ligand recognition and activation of the melanocortin-4 receptor. Cell Res. 2021. PMID 34433901 · doi:10.1038/s41422-021-00552-3

Questions

PT-141 FAQ

The CAS registry number of PT-141 is 189691-06-3. This is the free base; bremelanotide acetate is 1607799-13-2.

PT-141 has an average molecular weight of 1025.2 g/mol and a monoisotopic mass of 1024.5243 Da, molecular formula C50H68N14O10. Salt forms such as acetate weigh more; the Certificate of Analysis states the form of each lot.

PT-141 has 7 residues: XDHfRWK. One-letter convention here: X = non-proteinogenic residue, lowercase = D-amino acid. Ac-Nle-cyclo[Asp-His-D-Phe-Arg-Trp-Lys]-OH: N-acetyl-norleucine (X1); lactam bridge between the Asp2 side-chain carboxyl and the Lys7 side-chain amine (2->7); D-Phe4; C-terminal FREE ACID (the C-terminal-acid counterpart of melanotan II).

Neupeptides supplies PT-141 as a lyophilized powder in a sealed vial, for laboratory research use only. Storage: Store lyophilized at -20°C; protect from light. Each lot has a Certificate of Analysis, linked from the QR code on the box.