Opioid peptide
(Redirected from
Endogenous opioid
)
| Vertebrate endogenous opioids neuropeptide | |||||||||
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| Identifiers | |||||||||
| Symbol | Opiods_neuropep | ||||||||
| Pfam | PF01160 | ||||||||
| InterPro | IPR006024 | ||||||||
| PROSITE | PDOC00964 | ||||||||
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Opioid peptides or opiate peptides are
.Opioid-like peptides may also be absorbed from partially digested food (casomorphins, exorphins, and rubiscolins). Opioid peptides from food typically have lengths between 4–8 amino acids. Endogenous opioids are generally much longer.
Opioid peptides are released by
disulfide bond formation. It is speculated that this region might be important for neuropeptide processing.[1]
Endogenous
The human genome contains several homologous genes that are known to code for endogenous opioid peptides.
- The nucleotide sequence of the human gene for γ-endorphin.[3]
- The human gene for the enkephalins was isolated and its sequence described in 1982.[4]
- The human gene for dynorphins (originally called the "Enkephalin B" gene because of sequence similarity to the enkephalin gene) was isolated and its sequence described in 1983.[5]
- The PNOC gene encoding prepronociceptin, which is cleaved into nociceptin and potentially two additional neuropeptides.[1]
- Adrenorphin, amidorphin, and leumorphin were discovered in the 1980s.
- The endomorphins were discovered in the 1990s.
- Opiorphin and spinorphin, enkephalinase inhibitors (i.e., prevent the metabolism of enkephalins).
- Hemorphins, hemoglobin-derived opioid peptides, including hemorphin-4, valorphin, and spinorphin, among others.
While not peptides, codeine and morphine are also produced in the human body.[6][7]
| Opioid peptide | Amino acid sequence
|
Opioid receptor target(s) | References |
|---|---|---|---|
Enkephalins
|
|||
| Leu-enkephalin | YGGFL | δ-opioid receptor†, μ-opioid receptor† | [8][9][10] |
| Met-enkephalin | YGGFM | δ-opioid receptor†, μ-opioid receptor† | [8][9][10] |
Metorphamide |
YGGFMRRV-NH2 | δ-opioid receptor, μ-opioid receptor | [8] |
| Peptide E | YGGFMRRVGRPEWWMDYQKRYGGFL | μ-opioid receptor, κ-opioid receptor | [8] |
| Endorphins | |||
| α-Endorphin | YGGFMTSEKSQTPLVT | μ-opioid receptor, unknown affinity for other opioid receptors | [8] |
| β-Endorphin | YGGFMTSEKSQTPLVTLFKNAIIKNAYKKGE | μ-opioid receptor†‡, δ-opioid receptor† | [8][9][10][7] |
| γ-Endorphin | YGGFMTSEKSQTPLVTL | μ-opioid receptor, unknown affinity for other opioid receptors | [8] |
Dynorphins
|
|||
| Dynorphin A | YGGFLRRIRPKLKWDNQ | κ-opioid receptor†‡ | [8][9][11] |
Dynorphin A1–8 |
YGGFLRRI | κ-opioid receptor, μ-opioid receptor (partial agonist at δ-opioid receptor) | [12][13] |
| Dynorphin B | YGGFLRRQFKVVT | κ-opioid receptor | [8][9] |
| Big dynorphin | YGGFLRRIRPKLKWDNQKRYGGFLRRQFKVVT | κ-opioid receptor†‡ | [11][14][15] |
| Leumorphin | YGGFLRRQFKVVTRSQEDPNAYYEELFDV | κ-opioid receptor | [16][17][18][19] |
| α-Neoendorphin | YGGFLRKYPK | κ-opioid receptor | [8][9] |
| β-Neoendorphin | YGGFLRKYP | κ-opioid receptor | [8] |
| Nociceptin | |||
| Nociceptin | FGGFTGARKSARKLANQ | nociceptin receptor†‡ | [8][9][20] |
Endomorphins
|
|||
| Endomorphin-1 | YPWF-NH2 | μ-opioid receptor | [8][9] |
| Endomorphin-2 | YPFF-NH2 | μ-opioid receptor | [8][9] |
| † This symbol next to a receptor indicates that the corresponding peptide is a principal endogenous agonist of the receptor in humans. ‡ This symbol next to a receptor indicates that the corresponding peptide is the endogenous ligand with the highest known potency for the receptor in humans. | |||
Exogenous
Exogenous opioid substances are called exorphins, as opposed to endorphins. Exorphins include opioid food peptides, such as gluten exorphin and opioid food peptides, and are often contained in cereals and animal milk. Exorphins mimic the actions of endorphins by binding to and activating opioid receptors in the brain.
Common exorphins include:
- Casomorphin (from casein found in milk of mammals, including cows)
- Gluten exorphin (from gluten found in cereals wheat, rye, barley)
- Gliadorphin/gluteomorphin (from gluten found in cereals wheat, rye, barley)
- Soymorphin-5 (from soybean)
- Rubiscolin (from spinach)
Amphibian
Synthetic
- Zyklophin – semisynthetic KOR antagonist derived from dynorphin A
References
- ^ PMID 8710928.
- PMID 6254047.
- PMID 1069261.
- S2CID 4371340.
- S2CID 4315441.
- PMID 22578954.
Positive evolutionary pressure has apparently preserved the ability to synthesize chemically authentic morphine, albeit in homeopathic concentrations, throughout animal phyla. ... The apparently serendipitous finding of an opiate alkaloid-sensitive, opioid peptide-insensitive, µ3 opiate receptor subtype expressed by invertebrate immunocytes, human blood monocytes, macrophage cell lines, and human blood granulocytes provided compelling validating evidence for an autonomous role of endogenous morphine as a biologically important cellular signalling molecule (Stefano et al., 1993; Cruciani et al., 1994; Stefano and Scharrer, 1994; Makman et al., 1995). ... Human white blood cells have the ability to make and release morphine
- ^ a b "μ receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. 15 March 2017. Retrieved 28 December 2017.
Comments: β-Endorphin is the highest potency endogenous ligand ...
, citing:
Morphine occurs endogenously (Poeaknapo et. al. 2004) ...
Principal endogenous agonists (Human) [are]
β-endorphin (POMC, P01189), [Met]enkephalin (PENK, P01210), [Leu]enkephalin (PENK, P01210)- Poeaknapo C, Schmidt J, Brandsch M, Dräger B, Zenk MH (2004). "Endogenous formation of morphine in human cells". Proc. Natl. Acad. Sci. USA. 101 (39): 14091–6. PMID 15383669.
- Poeaknapo C, Schmidt J, Brandsch M, Dräger B, Zenk MH (2004). "Endogenous formation of morphine in human cells". Proc. Natl. Acad. Sci. USA. 101 (39): 14091–6.
- ^ PMID 22300099, in particular Table 1: Endogenous opioid peptides.
- ^ a b c d e f g h i Toll L, Caló G, Cox BM, Chavkin C, Christie MJ, Civelli O, Connor M, Devi LA, Evans C, Henderson G, Höllt V, Kieffer B, Kitchen I, Kreek MJ, Liu-Chen LY, Meunier JC, Portoghese PS, Shippenberg TS, Simon EJ, Traynor JR, Ueda H, Wong YH (10 August 2015). "Opioid receptors: Introduction". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 20 October 2017.
- ^ a b c "δ receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. 15 May 2017. Retrieved 28 December 2017.
Principal endogenous agonists (Human) [are]
β-endorphin (POMC, P01189), [Leu]enkephalin (PENK, P01210), [Met]enkephalin (PENK, P01210) - ^ a b "κ receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. 21 February 2017. Retrieved 28 December 2017.
Comments: Dynorphin A and big dynorphin are the highest potency endogenous ligands ...
Principal endogenous agonists (Human) [are]
big dynorphin (PDYN, P01213), dynorphin A (PDYN, P01213) - ^ "Dynorphin A 1–8". HMDB Version 4.0. Human Metabolome Database. 27 September 2017. Retrieved 20 October 2017.
Dynorphin A (1–8) is a fraction of Dynorphin A with only Tyr-Gly-Gly-Phe-Leu-Arg-Arg-Ile peptide chain.
- ^ "Dynorphin A-(1–8): Biological activity". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 20 October 2017.
- ^ "Big dynorphin: Biological activity". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 20 October 2017.
Principal endogenous agonists at κ receptor
. - ^ "Big dynorphin: Structure – Peptide Sequence". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. Retrieved 20 October 2017.
Peptide sequence
YGGFLRRIRPKLKWDNQKRYGGFLRRQFKVVT - PMID 19481570.
- ^ "Dynorphin B (1-29)". PubChem Compound. United States National Library of Medicine – National Center for Biotechnology Information. 23 December 2017. Retrieved 28 December 2017.
- S2CID 42419724.
- S2CID 24631286.
- ^ "NOP receptor". IUPHAR/BPS Guide to PHARMACOLOGY. International Union of Basic and Clinical Pharmacology. 18 August 2017. Retrieved 28 December 2017.
Natural/Endogenous Ligands
nociceptin/orphanin FQ
External links
- Opioid+Peptides at the U.S. National Library of Medicine Medical Subject Headings (MeSH)
| Authority control databases: National |
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