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Miscellaneous Neuropeptides
Published in Paul V. Malven, Mammalian Neuroendocrinology, 2019
Note in Table 5-2 that octapeptide met-ENK also differs from heptapeptide met- ENK at position 7. Figure 5-1 illustrates the location of these various enkephalin- related sequences within the linear 267-residue sequence of proenkephalin. The pentapeptide sequences are numbered sequentially starting at the N-terminus, and Leu-ENK is the sixth one. Other fragments of proenkephalin have been studied and assigned various names. The only one of these to be mentioned here is Peptide E which contains the fifth and sixth pentapeptide sequences as well as the intervening 15 residues (Figure 5-1). Therefore, peptide E contains 25 residues with met-ENK at its N-terminus and leu-ENK at its C-terminus. These naturally occurring EOPs of the enkephalin family share higher affinities for the delta subtype of opioid receptors.
Postulated Physiological and Pathophysiological Roles on Motility
Published in Edwin E. Daniel, Neuropeptide Function in the Gastrointestinal Tract, 2019
Hans-Dieter Allescher, Sultan Ahmad
Proenkephalin B, which is also termed prodynorphin and is expressed in the CNS and in the digestive tract, contains a variety of opioid peptides (α-neoendorphin, β-neoendorphin, dynorphin A [1—17, 1—13, 1—9, 1—8], dynorphin B [1—29, 1—12], and rimorphin).
Selective Post-Translational Processing of Opioid Peptides in Cardioregulatory Mechanisms of the Dorsal Medulla
Published in I. Robin A. Barraco, Nucleus of the Solitary Tract, 2019
William R. Millington, Michael D. Hirsch
Unlike POMC, proenkephalin contains multiple copies of the enkephalin sequence — six met- and one leu-enkephalin — amplifying the opioid “message” derived from the prohormone (Figure 1). Met- and leu-enkephalin are not, in all cases, the final products of proenkephalin processing, however; C-terminally extended peptides are also generated, particularly in the adrenal medulla.27,28 In brain, the major end product of the three enkephalin sequences near the prohormone’s N-terminal appears to be the pentapeptide, itself, although this is almost certainly not the case for the remaining met-enkephalin sequences which are expressed, at least in part, as C-terminally extended forms.28 Thus, both met-enkephalin-Arg-Gly-Leu (ME-RGL) and met-enkephalin-Arg-Phe (ME-RF) are abundant in brain and low levels of the peptide E derivatives, BAM-22,52 BAM-18,28,53 BAM-12,54 and metorphamide (BAM-8)55 are also present; BAM-18, rather than its larger precursors or metorphamide, appears to predominate, however.27,28 Like POMC, proenkephalin processing is regionally specific in the brain, and relative amounts of BAM-18, ME-RGL, ME-RF, and met-enkephalin vary extensively among brain regions,53 suggesting that C-terminally extended forms may be selectively expressed to mediate yet unidentified functions. Nevertheless, the greater abundance of met-enkephalin indicates that the pentapeptide, itself, rather than larger forms, is the predominant product of proenkephalin processing in the brain.
Localization and characterization of proenkephalin-A as a potential biomarker for kidney disease in murine and human kidneys
Published in Biomarkers, 2023
Michaela Alexandra Anna Fuchs, Julia Schrankl, Charlotte Wagner, Christoph Daniel, Armin Kurtz, Katharina Anna-Elisabeth Broeker
Among the candidates of newly identified makers for renal injury and predictors of GFR are proenkephalin-A (Penk), lipocalin-2 (Lcn2) and kidney-injury-molecule-1 (KIM-1). These markers have already found some implementation into clinical practice within the last five years and were studied in a number of patient cohorts (Viau et al.2010, Ng et al.2017, De Oliveira et al.2019, Beunders et al.2020, Hartman et al.2020). They show considerable potential for early diagnosis of kidney injury and rapid changes in GFR. In addition, these new markers might have predictive advantages by correlating high biomarker measurements with increased risk for severe adverse events in the follow-up periods of these studies (Kim et al.2017, Caironi et al.2018, Hartman et al.2020, Khorashadi et al.2020, Albert et al.2021). Of the proposed candidates, Penk has so far been reported as a good marker for predicting accurate renal function and long-term patient survival (Ng et al.2017, Caironi et al.2018, Emmens et al.2019, Khorashadi et al.2020).
Urine N-terminal pro-B-type natriuretic peptide and plasma proenkephalin are promising biomarkers for early diagnosis of cardiorenal syndrome type 1 in acute decompensated heart failure: a prospective, double-center, observational study in real-world
Published in Renal Failure, 2022
Hong-Liang Zhao, Hai-Juan Hu, Xiu-Jie Zhao, Wei-Wei Chi, De-Min Liu, Qian Wang, Wei Cui
Amino-terminal pro-B-type natriuretic peptide (NT-proBNP) is a well-known biomarker for the diagnosis and prognosis of ADHF, which has been linked to the occurrence and prognosis of CRS-1 [11–13]. However, most studies focused on blood NT-proBNP and none of them discussed urine NT-proBNP (uNT-proBNP) as a predictor of CRS-1 in ADHF patients. Enkephalin is an endogenous opioid peptide that regulates a variety of pathophysiological processes. Nevertheless, enkephalin is unstable and difficult to measure in plasma. As a precursor and surrogate marker of enkephalin, proenkephalin (PENK) is stable and simple to measure in plasma [14]. In recent years, PENK has gradually come into people’s awareness as a new biomarker for predicting the kidney dysfunction and prognosis in patients with ADHF [15,16]. However, it is still unknown whether PENK can early predict the occurrence of CRS-1. Therefore, this study first analyzes the uNT-proBNP and plasma PENK (pPENK) levels in ADHF patients on admission, explores whether they can early predict the occurrence of CRS-1, and finally evaluates the vulnerable-phase prognostic value of uNT-proBNP, pPENK, and CRS-1 for ADHF patients.
Role of preovulatory concentrations of estradiol on timing of conception and regulation of the uterine environment in beef cattle
Published in Systems Biology in Reproductive Medicine, 2020
George A. Perry, Robert A. Cushman, Brandi L. Perry, Amanda K. Schiefelbein, Emmalee J. Northrop, Jerica J.J. Rich, Stephanie D. Perkins
Proenkephalin-A is the precursor of several individual enkephalins (Marx 1983). Transcript abundance of proenkephalin-A has been reported to increase fourfold during pregnancy in the rat uterus (Jin et al. 1988), and was increased by exposure to progesterone and decreased by exposure to RU486 (Cheon et al. 2002). Similarly, Jin and co-workers (1988) reported that expression in the rat uterus was greatest at metestrus and diestrus. In the current study, proenkephalin-A mRNA was not detected on Day 0 and was not different between treatments. However, expression increased from Day 5 to Day 10, then decreased to Day 16 of the cycle. This again supports the hypothesis that the uterus in the non-estrus animals may not be functioning properly to support proper embryo development and survival, even among proteins that are regulated by progesterone.