CTOP is a peptide that acts as a μ-opioid receptor antagonist.
CAT No: R1808
CAS No:103429-31-8
Synonyms/Alias:CTOP;CTOPA;103429-31-8;Ctop-NH2;Cys(2)-tyr(3)-orn(5)-pen(7)-amide;Phe-cycl(cys-tyr-trp-orn-thr-pen)thr-NH2;N-(1-amino-3-hydroxy-1-oxobutan-2-yl)-19-[(2-amino-3-phenylpropanoyl)amino]-10-(3-aminopropyl)-7-(1-hydroxyethyl)-16-[(4-hydroxyphenyl)methyl]-13-(1H-indol-3-ylmethyl)-3,3-dimethyl-6,9,12,15,18-pentaoxo-1,2-dithia-5,8,11,14,17-pentazacycloicosane-4-carboxamide;Phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide;L-Threoninamide, D-phenylalanyl-L-cysteinyl-L-tyrosyl-D-tryptophyl-L-ornithyl-L-threonyl-3-mercapto-L-valyl-, cyclic (2-7)-disulfide;FCYWXTXT;CTOP TFA;CTOP?;SCHEMBL1239661;CHEBI:230371;PZWWYAHWHHNCHO-UHFFFAOYSA-N;AS-85089;FP108621;C20160;L000207;H-D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (Disulfide bond between Cys2 and Pen7);
CTOP, also known as D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2, is a synthetic peptide that functions as a highly selective μ-opioid receptor antagonist. Structurally engineered for enhanced receptor specificity and metabolic stability, CTOP has become a valuable tool in neuropharmacology and peptide-based signal transduction research. Its unique amino acid sequence and conformational properties allow for precise modulation of opioid receptor-mediated pathways, making it an indispensable compound for studies dissecting endogenous opioid systems, receptor-ligand interactions, and downstream signaling events. As a research-grade peptide, CTOP enables detailed exploration of the physiological and biochemical roles of μ-opioid receptors in various experimental models.
Receptor binding studies: CTOP is widely employed in binding assays to characterize the pharmacological properties of μ-opioid receptors. Its high affinity and selectivity for these receptors allow researchers to delineate receptor subtypes, quantify receptor density, and assess competitive binding dynamics in both in vitro and ex vivo systems. By serving as a reference antagonist, it provides a benchmark for evaluating the potency and selectivity of novel opioid ligands, aiding in the development of more targeted pharmacological agents.
Signal transduction analysis: The peptide is instrumental in dissecting intracellular signaling cascades initiated by μ-opioid receptor activation. By competitively inhibiting endogenous or exogenous agonists, CTOP enables the assessment of downstream effectors such as G-protein activation, second messenger modulation, and kinase pathway engagement. This application is particularly valuable for elucidating the molecular mechanisms underlying opioid receptor function, desensitization, and cross-talk with other neurotransmitter systems.
Neuroscience and behavioral research: In neurobiological studies, CTOP is used to investigate the role of μ-opioid receptors in modulating synaptic transmission, neural circuitry, and behavior. By selectively blocking receptor activity, the peptide allows researchers to parse the contributions of endogenous opioids to processes such as pain perception, reward, and stress response. Its use in animal models supports the identification of receptor-specific effects on neural plasticity and behavioral phenotypes, facilitating a deeper understanding of opioid system physiology.
Peptide structure-activity relationship (SAR) studies: CTOP serves as a model compound in the design and evaluation of peptide-based ligands targeting G protein-coupled receptors (GPCRs). Its well-defined sequence and receptor selectivity provide a foundation for systematic modifications aimed at optimizing binding affinity, metabolic resistance, and functional activity. SAR studies using CTOP inform the rational design of next-generation peptide therapeutics and research probes with improved pharmacological profiles.
Analytical method development: The unique physicochemical and chromatographic properties of CTOP make it a useful standard for developing and validating analytical techniques such as high-performance liquid chromatography (HPLC) and mass spectrometry. Its stability and distinct retention characteristics facilitate method optimization for the detection, quantification, and purity assessment of peptide-based compounds in complex biological matrices. This application supports robust quality control and reproducibility in peptide research and development workflows.
2. Autoinhibition and phosphorylation-induced activation of phospholipase C-γ isozymes
4. Cationic cell-penetrating peptides are potent furin inhibitors
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