View source for Beta-endorphin

{{protein
| Name = proopiomelanocortin (adrenocorticotropin/ beta-lipotropin/ alpha-melanocyte stimulating hormone/ beta-melanocyte stimulating hormone/ beta-endorphin)
| caption = 
| image = beta-endorphin.png
| width = 300
| HGNCid = 9201
| Symbol = POMC
| AltSymbols = 
| EntrezGene = 5443
| OMIM = 176830
| RefSeq = NM_000939
| UniProt = P01189
| PDB = 
| ECnumber = 
| Chromosome = 2
| Arm = p
| Band = 23
| LocusSupplementaryData = 
}}
'''β-[[endorphin]]''' is an [[endogenous]] [[opioid]] [[peptide]] [[neurotransmitter]] found in the [[neuron]]s of both the [[central nervous system|central]] and [[peripheral nervous system]]. 

The amino acid sequence is: [[tyrosine|Tyr]]-[[Glycine|Gly]]-Gly-[[Phenylalanine|Phe]]-[[Methionine|Met]]-[[Threonine|Thr]]-[[Serine|Ser]]-[[glutamic acid|Glu]]-[[Lysine|Lys]]-Ser-[[Glutamine|Gln]]-Thr-[[Proline|Pro]]-[[Leucine|Leu]]-[[Valine|Val]]-Thr-Leu-Phe-Lys-[[Asparagine|Asn]]-[[Alanine|Ala]]-[[Isoleucine|Ile]]-Ile-Lys-Asn-Ala-Tyr-Lys-Lys-Gly-Glu<ref>[http://www.genome.ad.jp/dbget-bin/www_bget?compound+C02210+C11684+C16041+C16042+C16043+C15890+C15891+C01574+C16135+C01516+-s DBGET]</ref>

==Formation==
β-endorphin is a peptide, 31 amino acids long, resulting from processing of the precursor [[proopiomelanocortin]] (POMC). (Note, POMC also gives rise to other peptide hormones, including ACTH ( [[Adrenocorticotropic hormone]] ), as well α- and γ-MSH ( [[Melanocyte-Stimulating Hormone]] ), resulting from intracellular processing by internal enzymes known as [[Proprotein convertase|prohormone convertase]]s.)

β-endorphin is found in neurons of the [[hypothalamus]], as well as the [[pituitary]] gland.

==Function==

It is an agonist of the opioid receptors, with evidence suggesting it serves as the endogenous [[ligand]] of the [[μ-opioid receptor]], the same receptor to which the chemicals extracted from [[opium]], such as [[morphine]], have their [[analgesic]] and [[Substance_use_disorder|addictive]] effects (indeed, the μ-opioid receptor was named based on its most renowned ligand, morphine).

==History==
β-endorphin was discovered from camel pituitary extracts by C.H. Li and David Chung.<ref>{{cite journal | url = http://www.pnas.org/cgi/content/abstract/73/4/1145 | author = Choh Hao Li and David Chung | title = Isolation and Structure of an Untriakontapeptide with Opiate Activity from Camel Pituitary Glands | journal = PNAS | year = 1976 | volume = 73 | pages = 1145–1148}}</ref> The discovery was amidst a flurry of discoveries made in the opioid field of "endogenous opiates", including [[Met-enkephalin]], [[Leu-enkephalin]], and [[dynorphin]]. Shortly thereafter, also in C.H. Li's laboratory, the opioid effects of this peptide were characterized.<ref>{{Cite journal | url = http://www.pnas.org/cgi/content/abstract/73/4/1145 | author = Horace H. Loh, L. F. Tseng, Eddie Wei, and Choh Hao Li | title = β-Endorphin is a Potent Analgesic Agent | journal = PNAS | year = 1976 | volume = 73 | pages = 2895–2898}}</ref> Some notable early questions which were investigated included anatomical questions (where in the body? where in the brain? where in the neuron?), pharmacological questions (how similar to morphine? how does potency differ? what part of the molecule confers opioid activity?), biochemical questions (how is it biosynthesized? how is the activity regulated? how is it metabolized?), behavioral questions (what is the effect of endogenous β-endorphin on activity levels), clinical questions (do deficiencies in endogenous β-endorphin lead to psychological disorders?), and therapeutic questions (is β-endorphin a viable treatment for morphine and heroin addiction, as well as chronic pain disorders?).

== Effects ==

It is used as an analgesic in the body to numb or dull pains. That is the reason why humans start to feel better immediately after an acute physical trauma even though the symptoms are still present. The reason the pain dulls is because it binds to and activates opioid receptors. β-endorphin has approximately 80 times the analgesic potency of [[morphine]].

β-endorphin is believed to have a number of other benefits, including:

*Boosting the [[immune system]]{{Fact|date=April 2007}}
*Slowing the growth of [[cancer]] cells <ref>[http://www.lowdosenaltrexone.org/ldn_and_cancer.htm LDN and Cancer<!-- Bot generated title -->]</ref>
*Promoting feeling of well-being
*Increasing relaxation

==References==
{{Reflist}}

== External links ==
* {{PubChem|16132316}} - β-endorphin
* {{PubChem|3081525}} - β-endorphin (1-9)
* {{PubChem|133304}} - β-endorphin (2-9)
* {{MeshName|β-endorphin}}

{{Opioid peptides}}

[[Category:Neurotransmitters]]

[[pl:Beta-endorfina]]
[[pt:Betaendorfina]]
[[ru:Бета-эндорфин]]