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 EL-4 thymoma cell line contains a peptidase which converts beta-endorphin to beta-endorphin 1-17 (gamma-endorphin), beta-endorphin 1-18, and their corresponding C-terminal fragments. This enzyme was purified approximately 700-fold to a single band on an SDS-polyacrylamide gel (106 kDa) in 16% yield. Estimation of the native molecular weight by molecular sieve chromatography gave a value of approximately 220 kDa, indicating that this enzyme is a dimer. Peptide sequencing demonstrated this activity can be attributed to insulin degrading enzyme, a previously described member of the inverzincin family (Hooper, 1994). Kinetic studies with a number of peptide substrates indicate that the enzyme preferentially cleaves on the amino side of hydrophobic or basic residues. However, the substrate specificity is more complex since not all basic and hydrophobic residues in a peptide are cleaved. The enzyme exhibits a requirement for a P'2 residue. On the basis of kcat/K(m) values, insulin, growth hormone releasing factor, and beta-endorphin are nearly equivalent substrates for the enzyme; however, growth hormone releasing factor and beta-endorphin exhibit a 40-fold higher kcat, but a 10-fold decreased affinity relative to insulin. A role for insulin-degrading enzyme as both a beta-endorphin-processing and -inactivating enzyme is implicated from these studies.
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PMID:Identification of gamma-endorphin-generating enzyme as insulin-degrading enzyme. 891 18

The presence and regulated expression of peptidase activity is a powerful mechanism with the potential to terminate or alter receptor recognition, cell membrane signal transduction, and physiological responses of immune cells to exogenous opioid peptides. In this study, the expression of an endopeptidase that hydrolyzes beta-endorphin to gamma-endorphin and other peptide products was investigated during in vitro differentiation and maturation of recombinant granulocyte-macrophage colony-stimulating factor (rGM-CSF) -derived, bone marrow-derived macrophages. In freshly isolated intact isolated mouse bone marrow cells the rate of beta-endorphin hydrolysis is undetectable (<0.1 nmol beta-endorphin hydrolyzed/h/10[6] cells). However, total intracellular beta-endorphin hydrolytic activity was increased significantly to 20.0 +/- 1.7 nmol/h/10(6) cells in the mature mouse macrophages derived in vitro by culture with rGM-CSF. rGM-CSF-derived macrophages expressed significantly higher levels of both protein and mRNA for the major beta-endorphin endopeptidase, gamma-endorphin-generating enzyme/insulin-degrading enzyme (gamma-EGE/IDE). Moreover, this enzymatic activity appears to be responsible for cleavage of exogenous beta-endorphin by intact rGM-CSF-derived macrophages or peritoneal macrophages to generate gamma-endorphin and other peptide products.
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PMID:Increased expression of an endopeptidase (gamma-EGE/IDE) hydrolyzing beta-endorphin during differentiation and maturation of bone marrow macrophages. 940 Aug 16

In this study, increased expression of an endopeptidase hydrolyzing beta-endorphin (beta-Ep) to gamma-endorphin (gamma-Ep, beta-Ep1-17) was observed upon immobilized anti-CD3 stimulated activation of human peripheral blood CD4+ T cells (hCD4+ T cells). Although freshly isolated hCD4+ T cells are devoid of significant beta-Ep endopeptidase activity ( < 0.1 nmol h(-1) 10(6) cells (-1)), activation of these cells with immobilized anti-CD3 results in a time dependent appearance of beta-Ep endopeptidase activity which reaches a maximal value of 17.4+/-0.48 nmol h(-1) 10(6) cells(-1) after 48 h of culture. Significant up-regulation of both mRNA encoding IDE/gamma-EpGE and immunoreactive protein are observed in anti-CD3 stimulated hCD4+ T cells, indicating transcription and translation of IDE/gamma-EpGE may be elevated. No significant hydrolysis of exogenous beta-Ep is observed with intact hCD4+ T cells whether quiescent or activated or from preparations of hCD4+ T cell membranes. Therefore, this activity appears to be intracellular. Immunoreactive IDE/gamma-EpGE is detected inside activated hCD4+ T cells. Analysis of metabolites generated upon hydrolysis of beta-Ep with lysed activated hCD4+ T cell preparations identified the presence of: beta-Ep1-18, beta-Ep2-18, beta-Ep1-17, beta-Ep2-17, beta-Ep18-31, beta-Ep19-31, beta-Ep1-13, beta-Ep2-13, beta-Ep18-26, and beta-Ep20-31 as major metabolites and the majority of these are consistent with beta-Ep hydrolytic activity attributable to IDE/gamma-EpGE.
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PMID:Anti-CD3 activation of human CD4+ T cells increases expression of the intracellular beta-endorphin endopeptidase (IDE/gamma-EpGE). 962 98

The active site glutamate (Glu(111)) and the active site histidine (His(112)) of insulin-degrading enzyme (IDE) were mutated. These mutant enzymes exhibit, in addition to a large decrease in catalytic activity, a change in the substrate-velocity response from a sigmoidal one seen with the native enzyme (Hill coefficient > 2), to a hyperbolic response. With 2-aminobenzoyl-GGFLRKHGQ-N-(2,4-dinitrophenyl)ethylenediamine as substrate, ATP and triphosphate increase the reaction rate of the wild type enzyme some 50-80-fold. This effect is dampened with glutamate mutants to no effect or less than a 3-fold increase in activity and changed to inhibition with the histidine mutants. Sedimentation equilibrium shows the IDE mutants exhibit a similar oligomeric distribution as the wild type enzyme, being predominantly monomeric, with triphosphate having little if any effect on the oligomeric state. Triphosphate did induce aggregation of many of the IDE mutants. Thus, the oligomeric state of IDE does not correlate with kinetic properties. The His(112) mutants were shown to bind zinc, but with a lower affinity than the wild type enzyme. The glutamate mutants displayed an altered cleavage profile for the peptide beta-endorphin. Wild type IDE cleaved beta-endorphin at Leu(17)-Phe(18) and Phe(18)-Lys(19), whereas the glutamate mutants cleaved at these sites, but in addition at Lys(19)-Asn(20) and at Met(5)-Thr(6). Thus, active site mutations of IDE are suggested to not only reduce catalytic activity but also cause local conformational changes that affect the allosteric properties of the enzyme.
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PMID:Mutation of active site residues of insulin-degrading enzyme alters allosteric interactions. 1574 95

Treatment of an N-terminal-containing His6-tagged insulysin (His6-IDE) with proteinase K led to the initial cleavage of the His tag and linker region. This was followed by C-terminal cleavages resulting in intermediate fragments of approximately 95 and approximately 76 kDa and finally a relatively stable approximately 56 kDa fragment. The approximately 76 and approximately 56 kDa fragments exhibited a low level of catalytic activity but retained the ability to bind the substrate with a similar affinity as the native enzyme. The kinetics of the reaction of the IDE approximately 76 and approximately 56 kDa proteolytic fragments with a synthetic fluorogenic substrate produced hyperbolic substrate versus velocity curves, rather than the sigmoidal curve obtained with His6-IDE. The approximately 76 and approximately 56 kDa IDE proteolytic fragments were active toward the physiological peptides beta-endorphin, insulin, and amyloid beta peptide 1-40. Although activity was reduced by a factor of approximately 103-104 with these substrates, the relative activity and the cleavage sites were unchanged. Both the approximately 76 and approximately 56 kDa fragments retained the regulatory cationic binding site that binds ATP. Thus, the two proteinase K cleavage fragments of IDE retain the substrate- and ATP-binding sites but have low catalytic activity and lose the allosteric kinetic behavior of IDE. These data suggest a role of the C-terminal region of IDE in allosteric regulation.
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PMID:Proteolytic fragments of insulysin (IDE) retain substrate binding but lose allosteric regulation. 1715 46

The regional distribution and cellular localization of insulin-degrading enzyme (IDE) was studied in adult human brain and pituitary by means of immunhistochemistry. We show that the enzyme is widely but unevenly distributed in human brain, with hypothalamic neurons showing the strongest immunoreaction. Strong to moderate immunostaining for the enzyme was observed in multiple cortical areas, hippocampus, cerebellum, and brain stem. Cellularly, IDE was mainly confined to neurons, but it was also present in oligodendrocytes, choroid plexus, and some blood vessel endothelial cells. A strong immunoreaction was seen in a subset of adenohypophysial cells. Some immunolabeling was also present in the neurohypophysis. The putative importance of the distribution of the enzyme in brain and pituitary is discussed in relation to its main known substrates, insulin, Abeta, and beta-endorphin.
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PMID:Regional and cellular distribution patterns of insulin-degrading enzyme in the adult human brain and pituitary. 1822 93

Numerous studies have investigated the behavioural effects of beta-endorphin, both endogenous and exogenously applied. However, the potential for biotransformation of beta-endorphin in the extracellular space of the brain has not been previously directly addressed in vivo. Utilising microinfusion/microdialysis and matrix-assisted laser desorption/ionisation mass spectrometry, we investigated beta-endorphin biotransformation in the striatum of rats. We infused 1.0 nmol beta-endorphin into the striatum of adult male Fischer rats and observed rapid cleavage resulting in beta-endorphin 1-18, as well as several fragments resulting from further N-terminal degradation. In vitro studies with incubation of full-length beta-endorphin, with and without protease inhibitors, in the incubation fluid of isolated striatal slices indicate that beta-endorphin is initially cleaved predominantly at the Phe(18)-Lys(19), position, as well as at the Leu(17)-Phe(18) position. Investigations of cerebrospinal fluid revealed similar enzymatic cleavage of beta-endorphin. The observed pattern of cleavage sites (Phe(18)-Lys(19) and Leu(17)-Phe(18)) is consistent with published in vitro studies of purified insulin-degrading enzyme cleavage of beta-endorphin. The binding affinities of full-length beta-endorphin, as well as previously identified beta-endorphin fragments alpha-endorphin (beta-endorphin 1-16) and gamma-endorphin (beta-endorphin 1-17), and the fragment identified in the present study, beta-endorphin 1-18, at heterologously expressed mu, delta and kappa-opioid receptors, respectively, were determined; the affinity of the truncation fragments is reduced at each of the receptors compared to the affinity of full length beta-endorphin.
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PMID:Extracellular biotransformation of beta-endorphin in rat striatum and cerebrospinal fluid. 1836 1

Insulin-degrading enzyme (IDE) is a neutral thiol metalloprotease, which cleaves insulin with high specificity. Additionally, IDE hydrolyzes Abeta, glucagon, IGF I and II, and beta-endorphin. We studied the expression of IDE protein in postmortem brains of patients with schizophrenia and controls because: (1) the gene encoding IDE is located on chromosome 10q23-q25, a gene locus linked to schizophrenia; (2) insulin resistance with brain insulin receptor deficits/receptor dysfunction was reported in schizophrenia; (3) the enzyme cleaves IGF-I and IGF-II which are implicated in the pathophysiology of the disease; and (4) brain gamma-endorphin levels, liberated from beta-endorphin exclusively by IDE, have been reported to be altered in schizophrenia. We counted the number of IDE immunoreactive neurons in the dorsolateral prefrontal cortex, the hypothalamic paraventricular and supraoptic nuclei, and the basal nucleus of Meynert of 14 patients with schizophrenia and 14 matched control cases. Patients had long-term haloperidol treatment. In addition, relative concentrations of IDE protein in the dorsolateral prefrontal cortex were estimated by Western blot analysis. There was a significantly reduced number of IDE expressing neurons and IDE protein content in the left and right dorsolateral prefrontal cortex in schizophrenia compared with controls, but not in other brain areas investigated. Results of our studies on the influence of haloperidol on IDE mRNA expression in SHSY5Y neuroblastoma cells, as well as the effect of long-term treatment with haloperidol on the number of IDE immunoreactive neurons in rat brain, indicate that haloperidol per se, is not responsible for the decreased neuronal expression of the enzyme in schizophrenics. Haloperidol however, might exert some effect on IDE, through changes of the expression levels of its substrates IGF-I and II, insulin and beta-endorphin. Reduced cortical IDE expression might be part of the disturbed insulin signaling cascades found in schizophrenia. Furthermore, it might contribute to the altered metabolism of certain neuropeptides (IGF-I and IGF-II, beta-endorphin), in schizophrenia.
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PMID:Reduced neuronal expression of insulin-degrading enzyme in the dorsolateral prefrontal cortex of patients with haloperidol-treated, chronic schizophrenia. 2187 64

Insulin-degrading enzyme (IDE) or insulysin is a highly conserved Zn(2+) -dependent endopeptidase with an "inverted" HxxEH motif. In vivo, IDE contributes to regulate the steady state levels of peripheral insulin and cerebral amyloid beta peptide (Abeta) of Alzheimer's disease. In vitro, substrates of IDE include a broad spectrum of peptides with relevant physiological functions such as atrial natriuretic factor, insulin-like growth factor-II, transforming growth factor-alpha, beta-endorphin, amylin or glucagon. The recently solved crystal structures of an inactive IDE mutant bound to four different substrates indicate, in accordance with previous compelling biochemical data, that peptide backbone conformation and size are major determinants of IDE recognition and substrate selectivity. IDE-N and IDE-C halves contribute to substrate binding and may rotate away from each other leading to open and closed conformers that permit or preclude the entry of substrates. Noteworthy, stabilization of substrate beta strands in their IDE-bound form may explain the preference of IDE for peptides with a high tendency to self-assembly as amyloid fibrils. These structural requirements may underlie the capability of some amyloid peptides of forming extremely stable complexes with IDE and raise the possibility of a dead-end chaperone-like function of IDE independent of catalysis. Furthermore, the recent recognition of IDE as a varicella zoster virus receptor and its putative involvement in muscle cell differentiation, steroid receptor signaling or proteasome modulation suggest that IDE is a multi-functional protein with broad and relevant roles in several basic cellular processes. Accordingly, IDE functions, regulation or trafficking may partake in the molecular pathogenesis of major human diseases and become potential targets for therapeutic intervention.
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PMID:Insulin-degrading enzyme: structure-function relationship and its possible roles in health and disease. 1992 17