PT-141

PT-141 is a cyclic heptapeptide whose lactam-bridged backbone constrains the molecule into a conformation that engages the melanocortin-receptor family with a documented preference for MC4R relative to MC1R, MC3R, and MC5R. The structural difference from Melanotan-II — a free C-terminal carboxylic acid rather than a primary amide — is the principal driver of this MC4R-shifted selectivity profile in published binding-affinity studies. Pharmacokinetic descriptors documented in published animal-model investigations include moderate plasma residence under standard parenteral paradigms. Interaction profile in the literature centers on Gs-coupled cAMP signaling activation downstream of MC4R engagement, with downstream investigations of central-melanocortin-pathway physiology in rodent-model paradigms. All activity descriptors here are framed as documented in published work. Structural confirmation is established by mass spectrometry molecular-ion match and HPLC-validated purity on each Certificate of Analysis.

Experimental domains documented in the published literature include MC4R-selective ligand pharmacology, structure-activity studies probing the role of C-terminal chemistry in melanocortin-receptor subtype preference, central-nervous-system melanocortin-pathway investigations in animal-model contexts, in-vitro cAMP signaling assays in receptor-expressing cell lines, and comparative work alongside Melanotan-II to dissect amide-versus-acid C-terminal effects on receptor engagement. Investigators have also characterized PT-141 in screening paradigms for MC4R-selective ligand discovery and in receptor-internalization kinetic studies. Use in laboratory research extends to mechanism-elucidation paradigms where the molecule serves as a probe for MC4R-driven signaling in central pathways. The reference standard is supplied for these and equivalent in-vitro experimental contexts only, with no associated guidance for human, clinical, cosmetic, or veterinary application.

Each lot is characterized by reverse-phase HPLC for chromatographic purity and by mass spectrometry for molecular-ion confirmation against the C50H68N14O10 empirical formula. Purity is reported as an HPLC-area percentage on the Certificate of Analysis distributed with every lot, alongside the molecular-weight match within instrument tolerance. Peptide content where applicable is determined by amino-acid analysis or nitrogen-content assay following the analytical method specified on the COA. Residual solvent and water content are reported categorically when these parameters are part of the lot's release specification. The COA records the lot identifier, manufacturing date, and analytical method versions used, providing a traceable provenance chain from synthesis through release. Researchers requiring batch-level analytical detail should reference the COA distributed with the supplied material.

For laboratory storage, the lyophilized reference standard should be held at −20°C in its sealed, light-protected container until ready for analytical use. Allow vials to equilibrate to ambient temperature before opening to avoid moisture condensation on the lyophile. Reconstitution for in-vitro experimental use is typically performed in bacteriostatic water or a researcher-selected buffer compatible with the downstream assay; once reconstituted, store the working solution at 2–8°C and characterize stability in the relevant buffer prior to extended storage. Avoid repeated freeze-thaw cycles of reconstituted material — single-use aliquots are preferred for experiments where peptide integrity is assay-critical. These handling parameters reflect general best-practice for lyophilized peptide reference standards and do not constitute preparation guidance for human, cosmetic, or veterinary application.