Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P01189 (beta-endorphin)
 21,003 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The distribution of FMRFamidelike peptides was studied in the nervous system of the lobster Homarus americanus by using immunocytochemical and radioimmunological techniques. By radioimmunoassay FMRFamidelike immunoreactivity (FLI) was found in low levels (ca. 1 pmol/mg protein) throughout the ventral nerve cord and in much higher amounts (60-100 pmol/mg protein) in the neurosecretory pericardial organs. Immunocytochemical studies showed FLI in approximately 300-350 cell bodies, and in distinct neuropil regions, neuronal fiber tracts, and varicose endings. Specificity of the immunostaining was tested by preabsorbing the antiserum with FMRFamide, with peptides having similar carboxyl termini to FMRFamide (Met-enkephalin-Arg-Phe, Phe-Met-Arg-Tyr-amide), with several amidated peptides (alpha-melanocyte-stimulating hormone, substance P, oxytocin), and with proctolin, a peptide found widely distributed in the lobster nervous system. Of these substances, only FMRFamide blocked the staining. In addition to the pericardial organs, significant levels of FLI were found in neurosecretory regions associated with thoracic second roots and in the connective tissue sheath that surrounds the ventral nerve cord. In all three regions, immunocytochemical studies showed the FLI to be localized to fine fibers and associated terminal varicosities lying close to the surface of the tissue, with no obvious target in their immediate vicinity. When examined at the ultrastructural level, the immunoreactive varicosities of the thoracic second roots and of the ventral nerve cord sheaths were found a few microns from the surface of the tissue and contained electron-dense granules. In the immunoreactive nerve cord sheath endings, in addition to the large, dense granules, small, clear vesicles were found. The appearance and location of these terminals suggest a neurohormonal role for FMRFamidelike peptides in lobsters. The observation that low levels of FLI are found in the hemolymph supports this suggestion. In addition, the localization of FLI to particular neuronal somata, fiber tracts, and neuropil regions suggests possible functional roles for these peptides in (1) integration of visual and olfactory information, (2) function of the anterior and posterior gut, and (3) the control of exoskeletal muscles.
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PMID:FMRFamidelike peptides of Homarus americanus: distribution, immunocytochemical mapping, and ultrastructural localization in terminal varicosities. 332 67

Recently, the presence and the concomitant release with catecholamines of metenkephalin and other pro-enkephalin A deriving peptides have been demonstrated in the adrenal medulla of various mammals and man. As high amounts of catecholamines are released in the newborn at delivery, probably following the stress of parturition, a similar release of met-enkephalin and other pro-enkephalin A deriving peptides from the newborn chromaffin tissue may be hypothesized. In the present study we investigate the occurrence of met-enkephalin-like immunoreactivity and enkephalinase (quite a specific enkephalin degrading enzyme) in cord and newborn plasma at different hours after birth. Our results show the presence of high met-enkephalin-like immunoreactivity levels in cord and newborn plasma with respect to normal adult values. On the contrary, cord blood enkephalinase activity was lower than in adult subjects and further decreased during the first hours of life. A positive correlation was found between the two parameters. These data seem to indicate a release of met-enkephalin-like peptides from the newborns' sympathoadrenal tissue following the stress of delivery and in the first hours of life.
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PMID:Met-enkephalin-like immunoreactivity (MELI) and enkephalinase activity (EKA) in cord blood and newborns in the first hours of life. 352 98

Total RNA has been prepared from human leukocytes from patients with chronic lymphoblastic leukemia (CLL) as well as from post mortem human caudate nucleus, hypothalamus, cerebellum and cerebral cortex. Dot-blot and Northern blot analysis, using a human proenkephalin A clone and SP-6 derived "complementary" proenkephalin A RNA respectively, revealed the existence of proenkephalin A-like RNA:s in CLL-leukocytes with the same characteristics as in caudate nucleus, hypothalamus, and cortex. Furthermore, RIA and Western blot analysis confirmed that immunoreactive pro-enkephalin A activity is present in human CLL-leukocytes. The progress in DNA recombinant technology has allowed the study of opioid peptide regulation at the transcriptional and translational-posttranslational level. Studies on the distribution and quantitation of preproenkephalin A mRNA in bovine, rat and human central nervous system (CNS) have recently been reported. Different opioid peptides, related to the enkephalins, dynorphins and beta-endorphin have also been detected in tissues outside the CNS including the adrenal medulla and in pheochromocytomas. Northern blot analysis and cDNA-cloning confirmed that the proenkephalin A gene is indeed expressed in these tissues. Proenkephalin A derived peptides are potentially significant in nervous disorders. We have chosen to investigate whether the corresponding gene is expressed not only in CNS-tissues but also in human leukocytes, cells readily obtained in individual patients.
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PMID:Proenkephalin A-like mRNA in human leukemia leukocytes and CNS-tissues. 378 78

The inhibitory activity of opioid peptides derived from pro-opiomelanocortin (POMC), pro-enkephalin A and pro-enkephalin B (= pro-dynorphin) on the electrically evoked twitch of the rat vas deferens (RVD) was evaluated. The POMC-derived beta-endorphin exhibits the greatest potency on this preparation. In addition, all peptides derived from pro-enkephalin A show full agonistic activity with BAM-22P and peptide E as the most potent peptides. In contrast, the majority of peptides derived from pro-enkephalin B (= pro-dynorphin) were essentially inactive on this tissue. Moreover, no antagonistic properties of these peptides were demonstrable in this preparation; thus the opioid receptors present in the RVD (putative epsilon receptors) might not possess any particular affinity for the pro-enkephalin B derived peptides.
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PMID:Opiate activity of peptides derived from the three opioid peptide families on the rat vas deferens. 609 92

Adrenal chromaffin granules contain at least 10 peptides, ranging in size from 3 to 5 kilodaltons, that yield, upon digestion with trypsin, peptides that show specific binding to opiate receptors. All are distinctly different from beta-endorphin. Two of these peptides have been purified to homogeneity and subjected to chemical analysis. One is apparently a [Met]enkephalin precursor containing two copies of the [Met]enkephalin sequence. The other peptide contains both [Leu]enkephalin and [Met]enkephalin sequences and is presumably a common precursor of the two forms of enkephalin.
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PMID:Probable precursors of [Leu]enkephalin and [Met]enkephalin in adrenal medulla: peptides of 3-5 kilodaltons. 624

When deplasticized Epon sections were treated with endo- and/or exopeptidases prior to incubation with antibodies, the neuropeptide immuno-reactivity of secretory nerves was often altered in a predictable way. Cleavage of neurosecretory material in octopus nerves by trypsin and carboxypeptidase-B enhanced enkephalin-like immunoreactivity, while Molluscan neuropeptide-like immunoreactivity was prevented by tryptic cleavage. The enzyme effects indicated the occurrence of a heptapeptide (Tyr-Gly-Gly-Phe-Met/Leu-Arg-Phe) that contains both the enkephalin and the Molluscan neuropeptide sequence. Vasopressin terminals of the rat neurohypophysis, which presumably contain enkephalin precursor sequences, exhibited enkephalin-like immunostaining after tryptic cleavage. ACTH/beta-endorphin cells of the rat intermediate pituitary, which synthesize the enkephalin sequence at the N-terminus of Beta-endorphin, exhibited enkephalin=like immunoreactivity when sections were treated with alpha-chymotrypsin or trypsin, but not after incubation with leucine-aminopeptidase or carboxypeptidase-B. Enkephalin-like immunostaining could not be induced in any way in ACTH/beta-endorphin cells of the anterior pituitary. Enzymatic cleavage may give additional information in immunocytochemical localization studies on neuropeptide sequences in secretory nerves and hormonal granules.
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PMID:Enzymatic cleavage prior to antibody incubation as a method for neuropeptide immunocytochemistry. 628 42

A large number of opioid peptides derived from the three established precursors, pro-opiomelanocortin (POMC), pro-enkephalin A (pro-enk A), and pro-enkephalin B (pro-enk B) were tested for their ability to inhibit electrically induced contractions of the isolated rabbit vas deferens, a preparation sensitive to k but not to mu opioid ligands. In the presence of enzyme inhibitors, all peptides exhibit roughly similar potencies, but the shorter peptides display lower potencies in the absence of enzyme inhibitors. This suggests that the loss in activity is due to their enzymatic degradation. It is concluded that the pro-enk B gene codes peptides with high k-receptor activities, whereas peptides produced by the POMC gene are devoid of k-receptor activity and the peptides, coded by the pro-enk A gene exhibit weak to moderate k-receptor activity.
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PMID:K receptor activities of the three opioid peptide families. 631 75

Enkephalin-containing polypeptides derived from pro-enkephalin A, pro-enkephalin B, or pro-opiomelanocortin were inhibitors of enkephalin degradation by aminoenkephalinases purified from cytosol or membranes. Of the peptides, Argo-Met-enkephalin was the most potent inhibitor for the aminoenkephalinases, with an IC50 of about 0.6 microM, it was more effective than bestatin (IC50 = 0.8-1.0 microM). This inhibition was partly due to substrate competition. Argo-Met-enkephalin was hydrolyzed by aminoenkephalinases to form Arg, Tyr, and Gly-Gly-Phe-Met in a substrate-inhibited manner. The hexapeptide also inhibited the breakdown of Arg- and Tyr-beta-naphthylamide by the membrane aminoenkephalinase. Since Argo-Met-enkephalin did not inhibit leucine aminopeptidase, it was a more selective inhibitor than bestatin of Met-enkephalin breakdown by aminopeptidases. Argo-Met-enkephalin inhibited enkephalin breakdown by synaptosomal plasma membranes but not by brain slices. Our data suggest that in addition to their possible role as opioids, the enkephalin-containing polypeptides may be regulators of enkephalin levels.
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PMID:Enkephalin-containing polypeptides are potent inhibitors of enkephalin degradation. 665 12

Methionine-enkephalin(met-enkephalin)-, leucine-enkephalin(leu-enkephalin)-, methionine-enkephalin-Arg6-Phe7(met-enkephalin-Arg-Phe)- and methionine-enkephalin-Arg6-Gly7-Leu8(met-enkephalin-Arg-Gly-Leu)-like immunoreactivities(-LI) were studied in 16 pheochromocytomas by radioimmunoassays (RIAs) for these four opioid peptides. Met-enkephalin-Arg-Phe-LI and met-enkephalin-Arg-Gly-Leu-LI existed together with met-enkephalin-LI and leu-enkephalin-LI in 16 pheochromocytomas. Significant positive correlations were observed among contents of these four opioid peptides in 16 pheochromocytomas. The concentrations of these four opioid peptides in epinephrine producing pheochromocytomas were much higher than those in norepinephrine producing tumors. HPLC and gel exclusion chromatography followed by the RIAs showed the presence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe and met-enkephalin-Arg-Gly-Leu together with their high molecular weight forms. These results indicate the co-existence of met-enkephalin, leu-enkephalin, met-enkephalin-Arg-Phe, met-enkephalin-Arg-Gly-Leu and their high molecular weight forms derived from preproenkephalin A in human pheochromocytomas and suggest the association of preproenkephalin A synthesis with epinephrine production in human pheochromocytomas.
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PMID:Methionine-enkephalin, leucine-enkephalin methionine-enkephalin-Arg6-Phe7 and methionine-enkephalin-Arg6-Gly7-Leu8 in human pheochromocytoma. 666 56

Enkephalins are pentapeptides with opioid activity which are found in a wide variety of tissues. Studies of enkephalin-containing peptides from the adrenal gland have established that the mature pentapeptides are derived by proteolytic processing of a precursor protein. We have shown that human adrenal medullary tumours contain mRNA which can be translated in vitro to yield a single major enkephalin precursor. The sequence of cloned cDNA shows that the preproenkephalin mRNA encodes four copies of met-enkephalin, two copies of met-enkephalin extended sequences and one copy of leu-enkephalin; each copy is flanked by paired basic amino acids which are presumably recognised by the processing protease. We have used the cloned human cDNA as a hybridisation probe to detect the corresponding mRNAs in rat adrenal gland and, in smaller amounts, in rat brain. We have been unable to detect in brain any other cross-hybridising mRNAs which might encode other putative precursor proteins.
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PMID:The structure and expression of the preproenkephalin gene. 676 48


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