Biology:Proenkephalin
Proenkephalin (PENK), formerly known as proenkephalin A (since proenkephalin B was renamed prodynorphin), is an endogenous opioid polypeptide hormone which, via proteolyic cleavage, produces the enkephalin peptides met-enkephalin, and to a lesser extent, leu-enkephalin.[1] Upon cleavage, each proenkephalin peptide results in the generation of four copies of Met-enkephalin, two extended copies of met-enkephalin, and one copy of leu-enkephalin.[1] Contrarily, Leu-enkephalin is predominantly synthesized from prodynorphin, which produces three copies of it per cleavage, and no copies of Met-enkephalin. Other endogenous opioid peptides produced by proenkephalin include adrenorphin,[2] amidorphin,[3] BAM-18,[4] BAM-20P,[5] BAM-22P,[5] peptide B,[6] peptide E,[7] and peptide F.[8]
The following table lists the peptides that are derived from cleavage of the proenkephalin protein.[9]
| Peptide | Alternative Names | Amino acid positions |
|---|---|---|
| Met-enkephalin | Opioid growth factor (OGF) | 107–111 |
| PENK(114–133) | Neuropeptide E; ENK-20 | 114–133 |
| Leu-enkephalin | — | 150–154 |
| Met-enkephalin-Arg-Phe | MERF; Neuropeptide AF | 186–191 |
| Met-enkephalin-Arg-Gly-Leu | MERGL; Neuropeptide AM | 218–223 |
| PENK(237–258) | Neuropeptide F | 237–258 |
Clinical significance
Proenkephalin is produced by the medium spiny neurons of the striatum which undergo neurodegeneration in early stages of Huntington's disease (HD). PENK[10] and related peptides[11][12] measured in cerebrospinal fluid are proposed as potential biomarkers of disease progression in HD. Furthermore, PENK has been found associated with acute kidney injury[13] and glomerular filtration rate in steady-state and critically ill patients.[14][15]
See also
- Prodynorphin (Proenkephalin B)
- Proopiomelanocortin (POMC)
References
- ↑ 1.0 1.1 Donald W. Pfaff (2002). Hormones, brain, and behavior. Elsevier. pp. 173. ISBN 978-0-12-532109-9. https://books.google.com/books?id=cGbE2nC__Q0C&pg=PA173. Retrieved 25 November 2011.
- ↑ "Novel C-terminally amidated opioid peptide in human phaeochromocytoma tumour". Nature 305 (5936): 721–723. 1983. doi:10.1038/305721a0. PMID 6633641. Bibcode: 1983Natur.305..721M.
- ↑ "Isolation and structure of a novel C-terminally amidated opioid peptide, amidorphin, from bovine adrenal medulla". Nature 313 (5997): 57–59. 1985. doi:10.1038/313057a0. PMID 3965972. Bibcode: 1985Natur.313...57S.
- ↑ "Pharmacological properties of a proenkephalin A-derived opioid peptide: BAM 18". European Journal of Pharmacology 138 (3): 359–366. June 1987. doi:10.1016/0014-2999(87)90474-2. PMID 3040439.
- ↑ 5.0 5.1 "A new family of endogenous "big" Met-enkephalins from bovine adrenal medulla: purification and structure of docosa- (BAM-22P) and eicosapeptide (BAM-20P) with very potent opiate activity". Biochemical and Biophysical Research Communications 97 (4): 1283–1290. December 1980. doi:10.1016/S0006-291X(80)80005-2. PMID 7213356.
- ↑ "Purification and sequence of a non-opioid peptide derived from ovine proenkephalin: implications for possible species specific processing". Peptides 5 (5): 853–856. 1984. doi:10.1016/0196-9781(84)90105-0. PMID 6504720.
- ↑ "Peptide E and its products, BAM 18 and Leu-enkephalin, in bovine adrenal medulla and cultured chromaffin cells: release in response to stimulation". Journal of Neurochemistry 49 (6): 1824–1832. December 1987. doi:10.1111/j.1471-4159.1987.tb02443.x. PMID 3681299.
- ↑ "Structure of two adrenal polypeptides containing multiple enkephalin sequences". Archives of Biochemistry and Biophysics 204 (1): 392–395. October 1980. doi:10.1016/0003-9861(80)90048-X. PMID 7425644.
- ↑ "Involvement of pro-enkephalin-derived peptides in immunity". Developmental and Comparative Immunology 25 (3): 177–85. April 2001. doi:10.1016/s0145-305x(00)00047-1. PMID 11164883.
- ↑ "Proenkephalin Decreases in Cerebrospinal Fluid with Symptom Progression of Huntington's Disease". Movement Disorders 36 (2): 481–491. February 2021. doi:10.1002/mds.28391. PMID 33247616.
- ↑ "Decrease in a proenkephalin peptide in cerebrospinal fluid in Huntington's disease and progressive supranuclear palsy". Brain Research 479 (2): 397–401. February 1989. doi:10.1016/0006-8993(89)91648-X. PMID 2522341.
- ↑ "Cerebrospinal fluid levels of proenkephalin and prodynorphin are differentially altered in Huntington's and Parkinson's disease". Journal of Neurology 269 (9): 5136–5143. September 2022. doi:10.1007/s00415-022-11187-8. PMID 35737109.
- ↑ "Proenkephalin as a biomarker correlates with acute kidney injury: a systematic review with meta-analysis and trial sequential analysis". Critical Care 27 (1): 481. December 2023. doi:10.1186/s13054-023-04747-5. PMID 38057904.
- ↑ "Assessing GFR With Proenkephalin". Kidney International Reports 8 (11): 2345–2355. November 2023. doi:10.1016/j.ekir.2023.08.006. PMID 38025210.
- ↑ "Proenkephalin Compared to Conventional Methods to Assess Kidney Function in Critically Ill Sepsis Patients". Shock 54 (3): 308–314. September 2020. doi:10.1097/SHK.0000000000001510. PMID 31977957.
External links
- Pro-Enkephalin at the US National Library of Medicine Medical Subject Headings (MeSH)
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