Opiorphin

Opiorphin[1]
IUPAC name (2S,5S,8S,11S,14S)-14,17-diamino-8-benzyl-2,11-bis(3-guanidinopropyl)-5-(hydroxymethyl)-4,7,10,13,17-pentaoxo-3,6,9,12-tetraazaheptadecan-1-oic acid
Other names Gln-Arg-Phe-Ser-Arg; L-Glutaminyl-L-arginyl-L-phenylalanyl-L-seryl-L-arginine
Identifiers
CAS number	864084-88-8 Y
Jmol-3D images	Image 1
SMILES O=C([C@H](CO)NC([C@H](CC1=CC=CC=C1)NC([C@H](CCCNC(N)=N)NC([C@H](CCC(N)=O)N)=O)=O)=O)N[C@H](C(O)=O)CCCNC(N)=N
Properties
Molecular formula	C29H48N12O8
Molar mass	692.77 g mol−1
Y (verify) (what is: Y/N?) Except where noted otherwise, data are given for materials in their standard state (at 25 °C, 100 kPa)
Infobox references

Opiorphin is an endogenous chemical compound first isolated from human saliva. Initial research with mice shows the compound has a painkilling effect greater than that of morphine. It works by stopping the normal breakdown of enkephalins, natural pain-killing opioids in the spinal cord. It is a relatively simple molecule consisting of a five-amino acid polypeptide, Gln-Arg-Phe-Ser-Arg.^{[2][3][4][5][6][7][8][9]}

Opiorphin pentapeptide originates from the N-terminal region of the protein PROL1 (proline rich, lacrimal 1).^[2] Opiorphin inhibits three proteases: neutral ecto-endopeptidase (MME), ecto-aminopeptidase N (ANPEP)^[2] and perhaps also a dipeptidyl peptidase DPP3.^[7] Such action extends the duration of enkephalin effect where the natural pain killers are released physiologically in response to specific potentially painful stimuli, in contrast with administration of narcotics, which floods the entire body and causes many undesirable adverse reactions, including addiction liability and constipation.^{[10] [11]} In addition, opiorphin may exert anti-depressive action.^{[12] [13]}

Therapeutic application of opiorphin in humans would require modifying the molecule to avoid its rapid degradation in the intestine and its poor penetration of the blood-brain barrier.^[10][11]

See also

• RB-101
• Racecadotril

References

1. ^ Opiorphin at Sigma-Aldrich
2. ^ ^{a b c} Dickinson DP, Thiesse M (April 1996). "cDNA cloning of an abundant human lacrimal gland mRNA encoding a novel tear protein". Curr. Eye Res. 15 (4): 377–86. doi:10.3109/02713689608995828. PMID 8670737. 
3. ^ Andy Coghlan (November 13, 2006). "Natural-born painkiller found in human saliva". New Scientist. http://www.newscientist.com/article.ns?id=dn10514. 
4. ^ "Natural chemical 'beats morphine'". BBC News. November 14, 2006. http://news.bbc.co.uk/2/hi/health/6142842.stm. 
5. ^ Mary Beckman (November 13, 2006). "Prolonging Painkillers". ScienceNOW. http://sciencenow.sciencemag.org/cgi/content/short/2006/1113/3. 
6. ^ Stanovic S, Boranic M, Petrovecki M, Batinic D, Skodlar J, Nemet D, Labar B. Haematologia. 2000; 30(1):1-10.
7. ^ ^{a b} Thanawala V, Kadam VJ, Ghosh R (October 2008). "Enkephalinase inhibitors: potential agents for the management of pain". Current Drug Targets 9 (10): 887–894. doi:10.2174/138945008785909356. PMID 18855623. 
8. ^ Davies KP (March 2009). "The role of opiorphins (endogenous neutral endopeptidase inhibitors) in urogenital smooth muscle biology". The Journal of Sexual Medicine 6 Suppl 3: 286–291. doi:10.1111/j.1743-6109.2008.01186.x. PMC 2864530. PMID 19267851. http://www.pubmedcentral.nih.gov/articlerender.fcgi?tool=pmcentrez&artid=2864530. 
9. ^ Tian XZ, Chen J, Xiong W, He T, Chen Q (July 2009). "Effects and underlying mechanisms of human opiorphin on colonic motility and nociception in mice". Peptides 30 (7): 1348–1354. doi:10.1016/j.peptides.2009.04.002. PMID 19442408. 
10. ^ ^{a b} Rougeot C, Robert F, Menz L, Bisson JF, Messaoudi M (October 2010). "Systemically active human opiorphin is a potent yet non-addictive analgesic without drug tolerance effects". J Physiol Pharmacol 61 (4): 483–490. PMID 20814077. http://www.jpp.krakow.pl/journal/archive/08_10/pdf/483_08_10_article.pdf. 
11. ^ ^{a b} Popik P, Kamysz E, Kreczko J, Wróbel M (November 2010). "Human opiorphin: the lack of physiological dependence, tolerance to antinociceptive effects and abuse liability in laboratory mice". Behav Brain Res 213 (1): 88–93. doi:10.1016/j.bbr.2010.04.045. http://www.sciencedirect.com/science/article/pii/S0166432810003268. 
12. ^ Javelot H, Messaoudi M, Garnier S, Rougeot C (June 2010). "Human opiorphin is a naturally occurring antidepressant acting selectively on enkephalin-dependent delta-opioid pathways". J Physiol Pharmacol 61 (3): 355–362. http://www.jpp.krakow.pl/journal/archive/06_10/pdf/355_06_10_article.pdf. 
13. ^ Yang QZ, Lu SS, Tian XZ, Yang AM, Ge WW, Chen Q (February 2011). "The antidepressant-like effect of human opiorphin via opioid-dependent pathways in mice". Neuroscience Letters 489 (2): 131–135. http://linkinghub.elsevier.com/retrieve/pii/S0304-3940(10)01536-3.