PT-141 (Bremelanotide) | Laboratory Research Reagent

Melanocortin Receptor Research | Cyclic Heptapeptide | Batch COA

For laboratory research use only. Not for use in humans or animals.

TECHNICAL SPECIFICATIONS

CHEMICAL IDENTITY AND STRUCTURE

PT-141 is a synthetic cyclic heptapeptide with molecular formula C50H68N14O10 and approximate molecular weight 1,025 g/mol for the free base. Identifiers include PubChem CID 9941379, CAS 189691-06-3, DB11653, KEGG D06569, ChemSpider 8116997, and CHEMBL2104001.

The sequence is Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH. The lactam bridge connects the Asp2 side-chain carboxyl group and Lys7 side-chain amine. N-terminal acetylated norleucine, D-Phe4, and the cyclic constraint provide structural context for receptor-binding and peptide-stability research. The His-D-Phe-Arg-Trp motif is discussed as a receptor-contact region.

The listed systematic name is (3S,6S,9R,12S,15S,23S)-15-[(N-Acetyl-L-norleucyl)amino]-9-benzyl-6-{3-[(diaminomethylidene)amino]propyl}-12-(1H-imidazol-5-ylmethyl)-3-(1H-indol-3-ylmethyl)-2,5,8,11,14,17-hexaoxo-1,4,7,10,13,18-hexaazacyclotricosane-23-carboxylic acid.

The supplied material is described as the research-grade free base. PubChem CID 91971505 and CID 169434958 provide acetate-salt and acetate-hydrate references. Counter-ion and hydration state affect molecular formula and molecular weight, so concentration calculations should use the form specified in the batch documentation.

MOLECULAR STRUCTURE

PT-141 cyclic heptapeptide structure showing the Asp-Lys lactam bridge and peptide architecture, PubChem CID 9941379.

RECEPTOR AND LABORATORY ASSAY CONTEXT

The listed melanocortin receptor profile includes MC1R, MC3R, MC4R, and MC5R, with principal activity at MC1R and MC4R. Laboratory research examines receptor binding, cAMP signaling, and neural-cell activity. MC1R-expressing melanocyte systems and MC4R-expressing neuronal systems provide distinct cell-based assay contexts.

1. Receptor binding: Competitive radioligand displacement using [125I]-NDP-alpha-MSH, receptor-subtype profiling, and isoform-selective reporter systems.
2. Signaling measurements: cAMP accumulation in MC4R-expressing HEK293 cells, adenylate cyclase/PKA pathway readouts, antagonist competition, and calcium imaging.
3. Neuronal measurements: Electrophysiology, neuronal firing-rate assays, and c-Fos readouts in appropriate laboratory preparations.
4. Peptide stability: In vitro enzymatic degradation, amide-bond hydrolysis, mass spectrometry metabolite identification, and plasma-matrix stability assays.
5. Structure-activity measurements: Alanine-scan analogues, Trp indole modifications, Arg guanidinium interactions, and cyclic or linearized scaffold binding measurements.
6. Permeability and solvent context: Caco-2 permeability, enzyme stability, and P-glycoprotein efflux assays provide analytical research contexts for cyclic peptides.

These methods provide experimental questions and measurement endpoints. They do not establish outcomes for the supplied reagent.

ANALYTICAL QUALITY AND COA

Each batch is listed with ≥99% RP-HPLC purity, LC-MS molecular-weight verification and cyclic-scaffold characterization, and endotoxin screening below 0.25 EU/mg by LAL chromogenic method. The expected protonated molecular ion is approximately [M+H]+ 1026 for the free base.

The COA includes lot number, manufacturing date, and analytical results. HPLC purity and structural characterization address different analytical questions. LPS can activate TLR4/NF-kB signaling and confound receptor-related cell assays, making endotoxin documentation relevant to experimental controls.

STORAGE AND LABORATORY HANDLING

Store lyophilized material at 2–8 °C, desiccated and protected from light. Tryptophan at position 6 contains an indole side chain susceptible to oxidation in aqueous environments, particularly with light or thermal exposure. Oxidation products can affect receptor-binding measurements.

PBS or another aqueous diluent provides the listed solvent context. Evaluate solvent compatibility and solution stability for the selected assay. Laboratory solutions are listed for prompt analytical use and −20 °C aliquot storage. Limit repeated freezing and thawing. Consult the batch COA for handling and storage recommendations.

Use gloves, a laboratory coat, and protective eyewear. Profound Aminos lists monitored domestic USA cold-chain shipping from a climate-controlled facility.

CHEMICAL REFERENCE RECORDS

PubChem CID 9941379 provides the free-base identity record. CIDs 91971505 and 169434958 provide the acetate and acetate-hydrate references. KEGG D06569 provides additional compound annotations. These identifiers support laboratory material identification.

FREQUENTLY ASKED QUESTIONS

What is the intended laboratory context for PT-141?

PT-141 is supplied as a laboratory reagent for melanocortin receptor-binding, signaling, structural, and analytical research assays. For laboratory research use only. Not for use in humans or animals.

What chemical identifiers are listed for PT-141?

PT-141, also known as bremelanotide, has free-base PubChem CID 9941379, CAS 189691-06-3, molecular formula C50H68N14O10, and an approximate molecular weight of 1,025 g/mol. Additional identifiers include DB11653, KEGG D06569, ChemSpider 8116997, and CHEMBL2104001.

Which melanocortin receptors are referenced?

The listed receptor profile includes MC1R, MC3R, MC4R, and MC5R, with principal activity described at MC1R and MC4R. Receptor-binding and signaling measurements should be interpreted within the specific assay system.

What structural features characterize the peptide?

PT-141 is a cyclic heptapeptide with sequence Ac-Nle-cyclo(Asp-His-D-Phe-Arg-Trp-Lys)-OH. A lactam bridge connects Asp2 and Lys7. The sequence includes N-terminal acetylated norleucine and D-phenylalanine at position 4.

What laboratory assays are described?

Listed assays include radioligand displacement, cAMP accumulation in receptor-expressing cells, isoform-selective reporter measurements, calcium imaging, electrophysiology, mass spectrometry metabolite analysis, and peptide-degradation measurements.

What solvent-system considerations apply?

PBS or another aqueous diluent provides the listed laboratory solvent context. Select the solvent system and concentration according to assay requirements and batch documentation. Use the free-base molecular weight of approximately 1,025 g/mol when calculating molar concentrations for that form.

What does the batch COA document?

The batch COA lists RP-HPLC purity of at least 99%, LC-MS molecular-weight and cyclic-scaffold identity data, endotoxin screening below 0.25 EU/mg by LAL chromogenic method, lot number, and manufacturing date. COAs are available through the Profound Aminos COA portal.

How do the free-base and acetate registry references differ?

PubChem CID 9941379 identifies the free base, CID 91971505 identifies the acetate salt, and CID 169434958 identifies the acetate hydrate. Counter-ion and hydration state affect the molecular formula and molecular weight. Check the batch documentation for the supplied form.

What laboratory handling precautions are listed?

Use gloves, a laboratory coat, and protective eyewear. Protect the material and laboratory solutions from light to limit tryptophan oxidation. Follow batch documentation and institutional chemical-safety procedures.

What storage conditions are listed?

Store lyophilized material at 2–8 °C, desiccated and protected from light. Laboratory solution aliquots are listed for −20 °C storage and prompt analytical use. Limit repeated freezing and thawing and follow the batch COA recommendations.

For laboratory research use only. Not for use in humans or animals.