β-Endorphin

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Beta-Endorphin
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β-Endorphin
Names
IUPAC name
L-Tyrosylglycylglycyl-L-phenylalanyl-L-methionyl-L-threonyl-L-seryl-L-glutaminyl-L-lysyl-L-seryl-L-glutaminyl-L-threonyl-L-prolyl-L-leucyl-L-valyl-L-threonyl-L-leucyl-L-phenylalanyl-L-lysyl-L-asparaginyl-L-alanyl-L-isoleucyl-L-isoleucyl-L-lysyl-L-asparaginyl-L-alanyl-L-tyrosyl-L-lysyl-L-lysylglycyl-L-glutamine
Identifiers
3D model (
JSmol
)
ChEBI
ChemSpider
ECHA InfoCard
100.056.646 Edit this at Wikidata
IUPHAR/BPS
UNII
  • InChI=1S/C158H253N41O44S/c1-17-84(9)126(153(237)184-102(44-29-34-65-163)137(221)188-112(74-120(168)210)142(226)173-86(11)131(215)185-110(73-94-48-52-96(206)53-49-94)146(230)179-99(41-26-31-62-160)135(219)177-98(40-25-30-61-159)134(218)172-78-124(214)175-106(158(242)243)56-59-119(167)209)195-154(238)127(85(10)18-2)194-132(216)87(12)174-143(227)113(75-121(169)211)187-136(220)100(42-27-32-63-161)180-147(231)111(72-92-38-23-20-24-39-92)186-144(228)107(68-81(3)4)190-155(239)129(89(14)203)197-152(236)125(83(7)8)193-148(232)108(69-82(5)6)189-151(235)116-45-35-66-199(116)157(241)130(90(15)204)198-140(224)104(55-58-118(166)208)182-149(233)114(79-200)191-138(222)101(43-28-33-64-162)178-139(223)103(54-57-117(165)207)181-150(234)115(80-201)192-156(240)128(88(13)202)196-141(225)105(60-67-244-16)183-145(229)109(71-91-36-21-19-22-37-91)176-123(213)77-170-122(212)76-171-133(217)97(164)70-93-46-50-95(205)51-47-93/h19-24,36-39,46-53,81-90,97-116,125-130,200-206H,17-18,25-35,40-45,54-80,159-164H2,1-16H3,(H2,165,207)(H2,166,208)(H2,167,209)(H2,168,210)(H2,169,211)(H,170,212)(H,171,217)(H,172,218)(H,173,226)(H,174,227)(H,175,214)(H,176,213)(H,177,219)(H,178,223)(H,179,230)(H,180,231)(H,181,234)(H,182,233)(H,183,229)(H,184,237)(H,185,215)(H,186,228)(H,187,220)(H,188,221)(H,189,235)(H,190,239)(H,191,222)(H,192,240)(H,193,232)(H,194,216)(H,195,238)(H,196,225)(H,197,236)(H,198,224)(H,242,243)/t84-,85-,86-,87-,88+,89+,90+,97-,98-,99-,100-,101-,102-,103-,104-,105-,106-,107-,108-,109-,110-,111-,112-,113-,114-,115-,116-,125-,126-,127-,128-,129-,130-/m0/s1
    Key: WOPZMFQRCBYPJU-NTXHZHDSSA-N
  • InChI=1/C158H253N41O44S/c1-17-84(9)126(153(237)184-102(44-29-34-65-163)137(221)188-112(74-120(168)210)142(226)173-86(11)131(215)185-110(73-94-48-52-96(206)53-49-94)146(230)179-99(41-26-31-62-160)135(219)177-98(40-25-30-61-159)134(218)172-78-124(214)175-106(158(242)243)56-59-119(167)209)195-154(238)127(85(10)18-2)194-132(216)87(12)174-143(227)113(75-121(169)211)187-136(220)100(42-27-32-63-161)180-147(231)111(72-92-38-23-20-24-39-92)186-144(228)107(68-81(3)4)190-155(239)129(89(14)203)197-152(236)125(83(7)8)193-148(232)108(69-82(5)6)189-151(235)116-45-35-66-199(116)157(241)130(90(15)204)198-140(224)104(55-58-118(166)208)182-149(233)114(79-200)191-138(222)101(43-28-33-64-162)178-139(223)103(54-57-117(165)207)181-150(234)115(80-201)192-156(240)128(88(13)202)196-141(225)105(60-67-244-16)183-145(229)109(71-91-36-21-19-22-37-91)176-123(213)77-170-122(212)76-171-133(217)97(164)70-93-46-50-95(205)51-47-93/h19-24,36-39,46-53,81-90,97-116,125-130,200-206H,17-18,25-35,40-45,54-80,159-164H2,1-16H3,(H2,165,207)(H2,166,208)(H2,167,209)(H2,168,210)(H2,169,211)(H,170,212)(H,171,217)(H,172,218)(H,173,226)(H,174,227)(H,175,214)(H,176,213)(H,177,219)(H,178,223)(H,179,230)(H,180,231)(H,181,234)(H,182,233)(H,183,229)(H,184,237)(H,185,215)(H,186,228)(H,187,220)(H,188,221)(H,189,235)(H,190,239)(H,191,222)(H,192,240)(H,193,232)(H,194,216)(H,195,238)(H,196,225)(H,197,236)(H,198,224)(H,242,243)/t84-,85-,86-,87-,88+,89+,90+,97-,98-,99-,100-,101-,102-,103-,104-,105-,106-,107-,108-,109-,110-,111-,112-,113-,114-,115-,116-,125-,126-,127-,128-,129-,130-/m0/s1
    Key: WOPZMFQRCBYPJU-NTXHZHDSBY
  • CC[C@H](C)[C@@H](C(=O)N[C@@H]([C@@H](C)CC)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CC(=O)N)C(=O)N[C@@H](C)C(=O)N[C@@H](Cc1ccc(cc1)O)C(=O)N[C@@H](CCCCN)C(=O)N[C@@H](CCCCN)C(=O)NCC(=O)N[C@@H](CCC(=O)N)C(=O)O)NC(=O)[C@H](C)NC(=O)[C@H](CC(=O)N)NC(=O)[C@H](CCCCN)NC(=O)[C@H](Cc2ccccc2)NC(=O)[C@H](CC(C)C)NC(=O)[C@H]([C@@H](C)O)NC(=O)[C@H](C(C)C)NC(=O)[C@H](CC(C)C)NC(=O)[C@@H]3CCCN3C(=O)[C@H]([C@@H](C)O)NC(=O)[C@H](CCC(=O)N)NC(=O)[C@H](CO)NC(=O)[C@H](CCCCN)NC(=O)[C@H](CCC(=O)N)NC(=O)[C@H](CO)NC(=O)[C@H]([C@@H](C)O)NC(=O)[C@H](CCSC)NC(=O)[C@H](Cc4ccccc4)NC(=O)CNC(=O)CNC(=O)[C@H](Cc5ccc(cc5)O)N
Properties
C158H251N39O46S
Molar mass 3465.03 g·mol−1
Except where otherwise noted, data are given for materials in their standard state (at 25 °C [77 °F], 100 kPa).
checkY verify (what is checkY☒N ?)

β-Endorphin (beta-endorphin) is an

γ-endorphin.[2]

There are multiple forms of β-endorphins with the full sequence of

endorphin classes of neuropeptides;[1] all of the established endogenous opioid peptides contain the same N-terminal amino acid sequence, Tyr-Gly-Gly-Phe, followed by either -Met or -Leu.[1]

Function of β-endorphin has been known to be associated with

volume transmission into the ventricular system in response to a variety of stimuli, and novel stimuli in particular.[5]

Formation and structure

β-Endorphin is found in neurons of the

β-lipotropin, which is produced in the pituitary gland from a larger peptide precursor, proopiomelanocortin (POMC).[6] POMC is cleaved into two neuropeptides, adrenocorticotropic hormone (ACTH) and β-lipotropin.[7] The formation of β-endorphin is then the result of cleavage of the C-terminal region of β-lipotropin, producing a 31 amino acid-long neuropeptide with an alpha-helical secondary structure. However, POMC also gives rise to other peptide hormones, including α- and γ-melanocyte-stimulating hormone (MSH), resulting from intracellular processing by internal enzymes known as prohormone convertases
.

A significant factor that differentiates β-endorphin from other endogenous opioids is its

proteolytic enzymes, as its secondary structure makes it less vulnerable to degradation.[6]

This diagram depicts the formation of β-endorphin from the proopiomelanocortin gene in the pituitary gland. Portions of the second and third exon of this gene make up the proopiomelanocortin protein. The cleavage of the C-terminal end of this protein produces β-lipotropin, which is then cleaved again to form β-endorphin. The proopiomelanocortin protein is also a precursor to other neuropeptides and hormones, such as adrenocorticotropic hormone.
beta-endorphin
with each amino acid labeled.

Function and effects

β-Endorphin function is said to be divided into two main categories: local function and global function. Global function of β-endorphin is related to decreasing bodily stress and maintaining homeostasis resulting in pain management, reward effects, and behavioral stability. β-Endorphin in global pathways diffuse to different parts of the body through cerebral spinal fluid in the spinal cord, allowing for β-endorphin release to affect the peripheral nervous system. Localized function of β-endorphin results in release of β-endorphin in different brain regions such as the amygdala or the hypothalamus.

ACTH to modulate hormone system functioning. Neuroregulation by β-endorphin occurs through interference with the function of another neuropeptide, either by direct inhibition of neuropeptide release or induction of a signaling cascade that reduces a neuropeptide's effects.[7]

Opioid agonist

β-Endorphin is an agonist of the

G-protein coupled receptors, such that when β-endorphin or another opioid binds, a signaling cascade is induced in the cell.[10] Acetylation of the N-terminus of β-endorphin, however, inactivates the neuropeptide, preventing it from binding to its receptor.[6] The opioid receptors are distributed throughout the central nervous system and within the peripheral tissue of neural and non-neural origin. They are also located in high concentrations in the Periaqueductal gray, Locus coeruleus, and the Rostral ventromedial medulla.[11]

cannot be released from the presynaptic terminal of the neurons. These neurotransmitters are vital in the transmission of pain, and as β-Endorphin reduces the release of these substances, there is a strong analgesic effect.

Pain management

β-Endorphin has been primarily studied for its influence on

GABA, a neurotransmitter which prevents the release of dopamine.[7][15] Thus, the inhibition of GABA release by β-endorphin allows for a greater release of dopamine, in part contributing to the analgesic effect of β-endorphin.[7][15]
The combination of these pathways reduces pain sensation, allowing for the body to stop a pain impulse once it has been sent.

β-Endorphin has approximately 18 to 33 times the analgesic potency of morphine,[18] though its hormonal effect is species dependent.[8]

Exercise

β-Endorphin release in response to exercise has been known and studied since at least the 1980s.

runner's high.[20]

Sunlight

There is evidence that β-endorphin is released in response to ultraviolet radiation, either through sun exposure or artificial tanning.[21] This is thought to contribute to addiction behavior among excessive sunbathers and users of artificial tanning despite health risks.

Mechanism of action

β-Endorphin acts as an agonist that binds to various types of

G protein–coupled receptors(GPCRs), most notably to the mu, delta, and kappa opioid receptors. The receptors are responsible for supra-spinal analgesia.[medical citation needed
]

History

β-Endorphin was discovered in camel pituitary extracts by C.H. Li and David Chung.

γ-lipotropin. They noticed that the C-terminus region of this neuropeptide was similar to that of some enkephalins, suggesting that it may have a similar function to these neuropeptides. The C-terminal sequence of γ-lipotropin turned out to be the primary sequence of the β-endorphin.[6]

References

  1. ^ . Opioid Peptides
    β-Endorphin (also a pituitary hormone) ...
    Opioid peptides are encoded by three distinct genes. These precursors include POMC, from which the opioid peptide β-endorphin and several nonopioid peptides are derived, as discussed earlier; proenkephalin, from which met-enkephalin and leu-enkephalin are derived; and prodynorphin, which is the precursor of dynorphin and related peptides. Although they come from different precursors, opioid peptides share significant amino acid sequence identity. Specifically, all of the well-validated endogenous opioids contain the same four N-terminal amino acids (Tyr-Gly-Gly-Phe), followed by either Met or Leu ... Among endogenous opioid peptides, β-endorphin binds preferentially to μ receptors. ... Shared opioid peptide sequences. Although they vary in length from as few as five amino acids (enkephalins) to as many as 31 (β-endorphin), the endogenous opioid peptides shown here contain a shared N-terminal sequence followed by either Met or Leu.
  2. .
  3. .
  4. ^ DBGET
  5. ^
    PMID 25879522
    .
  6. ^ .
  7. ^ .
  8. ^ .
  9. ^ a b Borsodi A, Caló G, Chavkin C, Christie MJ, Civelli O, Cox BM, 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, Toll L, Traynor JR, Ueda H, Wong YH (15 March 2017). "Opioid receptors: μ receptor". IUPHAR/BPS Guide to Pharmacology. International Union of Basic and Clinical Pharmacology. Retrieved 26 May 2017. Principal endogenous agonists (Human)
    β-endorphin (POMC, P01189), [Met]enkephalin (PENK, P01210), [Leu]enkephalin (PENK, P01210) ...
    Comments: β-Endorphin is the highest potency endogenous ligand
  10. PMID 28419415
    .
  11. .
  12. .
  13. .
  14. .
  15. ^ .
  16. ^ .
  17. .
  18. .
  19. ^ .
  20. ^ Goldberg J (19 February 2014). "Exercise and Depression". WebMD. Retrieved 14 July 2014.
  21. ^ "Addicted to the Sun". hms.harvard.edu. 19 June 2014. Retrieved 29 August 2023.
  22. PMID 1063395
    .

External links