Editing Enkephalin (section)

{{Short description|Pentapeptide}}
{{infobox protein
|Name=
|caption=Met-enkephalin 3D structure, alpha-carbons shown as balls and labeled by residue.<ref name="pmid14990485">{{PDB|1plx}}; {{cite journal | vauthors = Marcotte I, Separovic F, Auger M, Gagné SM | title = A multidimensional 1H NMR investigation of the conformation of methionine-enkephalin in fast-tumbling bicelles | journal = Biophys. J. | volume = 86 | issue = 3 | pages = 1587–600 |date=March 2004 | pmid = 14990485 | pmc = 1303993 | doi = 10.1016/S0006-3495(04)74226-5 | bibcode=2004BpJ....86.1587M}}</ref>
|image=Met-enkephalin 1plx model 1.png
|width=
|HGNCid=8831
|Symbol=PENK
|AltSymbols=
|EntrezGene=5179
|OMIM=131330
|RefSeq=NM_006211
|UniProt=P01210
|PDB=
|ECnumber=
|Chromosome=8
|Arm=q
|Band=23
|LocusSupplementaryData=-q24
}}

An '''enkephalin''' is a [[peptide|pentapeptide]] involved in regulating [[nociception]] (pain sensation) in the body.  The enkephalins are termed endogenous [[ligand]]s, as they are internally derived (and therefore [[endogenous]]) and bind as [[ligand]]s to the body's [[opioid receptor]]s.  Discovered in 1975, two forms of enkephalin have been found, one containing [[leucine]] ("leu"), and the other containing [[methionine]] ("met"). Both are products of the proenkephalin [[gene]].<ref name="pmid6281660">{{cite journal | vauthors = Noda M, Teranishi Y, Takahashi H, Toyosato M, Notake M, Nakanishi S, Numa S | title = Isolation and structural organization of the human preproenkephalin gene | journal = Nature | volume = 297 | issue = 5865 | pages = 431–4 |date=June 1982 | pmid = 6281660 | doi =10.1038/297431a0 |bibcode = 1982Natur.297..431N | s2cid = 4371340 }}</ref>
* [[Met-enkephalin]] is Tyr-Gly-Gly-Phe-'''Met'''.
* [[Leu-enkephalin]] is Tyr-Gly-Gly-Phe-'''Leu'''.