CTOP

CTOP
	source ↗
Names
	IUPAC name (4S,7R,10S,13R,16S,19R)-N-[(2S,3R)-1-amino-3-hydroxy-1-oxobutan-2-yl]-19-[[(2R)-2-amino-3-phenylpropanoyl]amino]-10-(3-aminopropyl)-7-[(1R)-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
Identifiers
CAS Number	103429-31-8;
3D model (JSmol)	Interactive image;
ChEBI	CHEBI:230371;
ChemSpider	4470595;
KEGG	C20160;
PubChem CID	5311058;
	InChI InChI=1S/C50H67N11O11S2/c1-26(62)39(42(53)65)59-49(72)41-50(3,4)74-73-25-38(58-43(66)33(52)21-28-11-6-5-7-12-28)47(70)56-36(22-29-16-18-31(64)19-17-29)45(68)57-37(23-30-24-54-34-14-9-8-13-32(30)34)46(69)55-35(15-10-20-51)44(67)60-40(27(2)63)48(71)61-41/h5-9,11-14,16-19,24,26-27,33,35-41,54,62-64H,10,15,20-23,25,51-52H2,1-4H3,(H2,53,65)(H,55,69)(H,56,70)(H,57,68)(H,58,66)(H,59,72)(H,60,67)(H,61,71)/t26-,27-,33-,35+,36+,37-,38+,39+,40+,41-/m1/s1 Key: PZWWYAHWHHNCHO-FGHAYEPSSA-N;
	SMILES C(C=1C=2C(NC1)=CC=CC2)[C@H]3NC(=O)[C@H](CC4=CC=C(O)C=C4)NC(=O)[C@@H](NC([C@@H](CC5=CC=CC=C5)N)=O)CSSC(C)(C)[C@@H](C(N[C@@H]([C@@H](C)O)C(N)=O)=O)NC(=O)[C@]([C@@H](C)O)(NC(=O)[C@H](CCCN)NC3=O)[H];
Properties
Chemical formula	C50H67N11O11S2
Molar mass	1062.27 g·mol−1
	Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa). Infobox references

CTOP is an opioid antagonist cyclic peptide related to somatostatin.¹ It has been used in research about other opioid ligands.²³

Pharmacology

CTOP is described as a highly potent mu-opioid receptor antagonist. In mice, its analgesic effects are qualified as being more potent than naloxone's, a well-known opioid antagonist typically used as an antidote in humans.⁴ Additionally, CTOP appears to lack significant affinity at the delta and kappa opioid receptors, suggesting that this peptide is selective for the μ receptor.⁵

References

PubChem. "Phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide". pubchem.ncbi.nlm.nih.gov. Retrieved 2026-01-01.
Soini, S. L.; Ovaska, T.; Honkanen, A.; Hyytiä, P.; Korpi, E. R. (April 1998). "Brain opioid receptor binding of [3H]CTOP and [3H]naltrindole in alcohol-preferring AA and alcohol-avoiding ANA rats". Alcohol (Fayetteville, N.Y.). 15 (3): 227–232. doi:10.1016/s0741-8329(97)00125-0. ISSN 0741-8329. PMID 9539380.
Leite dos Santos, Gisele Graça; Casais e Silva, Luciana Lyra; Pereira Soares, Milena Botelho; Villarreal, Cristiane Flora (November 2012). "Antinociceptive properties of Micrurus lemniscatus venom". Toxicon. 60 (6): 1005–1012. Bibcode:2012Txcn...60.1005L. doi:10.1016/j.toxicon.2012.07.003. ISSN 1879-3150. PMID 22841808.
Gulya, K.; Kriván, M.; Nyolczas, N.; Sarnyai, Z.; Kovács, G. L. (1988-06-10). "Central effects of the potent and highly selective mu opioid antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) in mice". European Journal of Pharmacology. 150 (3): 355–360. doi:10.1016/0014-2999(88)90018-0. ISSN 0014-2999. PMID 2901358.
Hawkins, K. N.; Knapp, R. J.; Gehlert, D. R.; Lui, G. K.; Yamamura, M. S.; Roeske, L. C.; Hruby, V. J.; Yamamura, H. I. (1988). "Quantitative autoradiography of [3H]CTOP binding to mu opioid receptors in rat brain". Life Sciences. 42 (25): 2541–2551. doi:10.1016/0024-3205(88)90322-0. ISSN 0024-3205. PMID 2898716.

[1] PubChem. "Phenylalanyl-cyclo(cysteinyltyrosyl-tryptophyl-ornithyl-threonyl-penicillamine)threoninamide". pubchem.ncbi.nlm.nih.gov. Retrieved 2026-01-01.

[2] Soini, S. L.; Ovaska, T.; Honkanen, A.; Hyytiä, P.; Korpi, E. R. (April 1998). "Brain opioid receptor binding of [3H]CTOP and [3H]naltrindole in alcohol-preferring AA and alcohol-avoiding ANA rats". Alcohol (Fayetteville, N.Y.). 15 (3): 227–232. doi:10.1016/s0741-8329(97)00125-0. ISSN 0741-8329. PMID 9539380.

[3] Leite dos Santos, Gisele Graça; Casais e Silva, Luciana Lyra; Pereira Soares, Milena Botelho; Villarreal, Cristiane Flora (November 2012). "Antinociceptive properties of Micrurus lemniscatus venom". Toxicon. 60 (6): 1005–1012. Bibcode:2012Txcn...60.1005L. doi:10.1016/j.toxicon.2012.07.003. ISSN 1879-3150. PMID 22841808.

[4] Gulya, K.; Kriván, M.; Nyolczas, N.; Sarnyai, Z.; Kovács, G. L. (1988-06-10). "Central effects of the potent and highly selective mu opioid antagonist D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr-NH2 (CTOP) in mice". European Journal of Pharmacology. 150 (3): 355–360. doi:10.1016/0014-2999(88)90018-0. ISSN 0014-2999. PMID 2901358.

[5] Hawkins, K. N.; Knapp, R. J.; Gehlert, D. R.; Lui, G. K.; Yamamura, M. S.; Roeske, L. C.; Hruby, V. J.; Yamamura, H. I. (1988). "Quantitative autoradiography of [3H]CTOP binding to mu opioid receptors in rat brain". Life Sciences. 42 (25): 2541–2551. doi:10.1016/0024-3205(88)90322-0. ISSN 0024-3205. PMID 2898716.

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