Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound   Target Concepts: Gene/Protein Disease Symptom Drug Enzyme Compound

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Query: EC:3.4.24.11 (CD10)
9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two exocellular enzymes have been characterized in the culture media of sporulating Bacillus sphaericus 9602 : a gamma-D-glutamyl-(L) meso-diaminopimelate endopeptidase and a L-lysyl-D-alanine carboxypeptidase. These two enzymes and the corresponding membrane-bound peptidases found in Bacillus sphaericus and Bacillus subtilis strains have similar activities. Their separation is described. Both enzymes were precipitated between 25 and 65 per cent (NH4)2SO4 saturation and a first chromatography was carried out on a column of DEAE-cellulose. The separation was performed by chromatography on hydroxyapatite, each enzyme was finally filtered through Ultrogel AcA 34. After separation, the endopeptidase activity and the carboxypeptidase activity increased respectively 93 and 11 fold. Both enzymes have a molecular weight near 200 000. By gel electrophoresis at pH 8.5, they were shown to have different mobilities : the carboxypeptidase is more anionic than the endopeptidase.
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PMID:[Characterization and separation of exocellular gamma-D-glutamyl-(L)meso-diaminopimelate endopeptidase and LD-carboxypeptidase from Bacillus sphaericus 9602]. 1 31

Sublethal levels (10 to 100 micrograms/ml) of the chlorinated insecticide chlordane (1,2,4,5,6,7,8,8-octachloro-3a,4,7,7a-tetrahydro-4,7-methanoindan) were introduced into the growth medium of the marine bacterium, Aeromonas proteolytica. Chlordane inhibited the synthesis of an extracellular endopeptidase by almost 40% but exhibited no such inhibition of the extracellular aminopeptidase also produced during the growth cycle. Studied with 14C-labeled chlordane demonstrated that the insecticide was not biologically degraded under the test conditions used and that up to 75% of the recoverable chlordane was cell associated within 48 h. Studied with uniformly labeled L[14C]valine and [2-14C]uracil established that neither the transport nor the incorporation of these protein and ribonucleic acid precursors was inhibited by chlordane. Separation of the membrane fractions using isopycnic centrifugation localized 14C-labeled chlordane in the cytoplasmic membrane. Also, chlordane inhibited the membrane-bound adenosine 5'-triphosphatase while the soluble (released) form of this enzyme remained unaffected. These data indicate that chlordane resides in the cytoplasmic membrane and may cause specific alterations in membrane-associated activities.
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PMID:Evidence for the subcellular localization and specificity of chlordane inhibition in the marine bacterium Aeromonas proteolytica. 15 17

The ligand-binding properties of the gastrin-releasing peptide (GRP) receptor and the cellular processing of GRP have been studied in the small-cell lung cancer (SCLC) cell line COR-L42. Scatchard analysis of GRP receptor expression indicated a single class of high-affinity receptors (Kd 1.5 nM) and approx. 6700 receptors/cell. GRP bound to its receptor with a Ki of 2.4 nM. The bombesin-related peptides neuromedin B (NMB) and phyllolitorin also bound to GRP receptors with Ki values of 22.7 and 59.1 nM respectively. Binding of 125I-GRP to COR-L42 cells increased rapidly at 37 degrees, achieved a maximum at 10 min and declined rapidly thereafter. At 4 degrees C, maximum binding was achieved at 30 min and the subsequent decline in cell-associated radioactivity was slower than that seen at 37 degrees C. Acid/salt extraction, to separate surface-bound ligand from internalized GRP, indicated that after receptor binding 125I-GRP was rapidly internalized. To determine the pathway of 125I-GRP degradation, binding studies were carried out with the lysosomotropic agent chloroquine (5 mM), and with phosphoramidon (10 microM), an inhibitor of the membrane-bound enzyme (EC 3.4.24.11). Both agents markedly inhibited the degradation of GRP, indicating that this process involves a lysosomal pathway and a phosphoramidon-sensitive pathway, possibly involving the EC 3.4.24.11 enzyme. GRP receptor down-regulation was observed following a 10 min exposure to 100 nM-GRP. With longer pretreatment times the number of binding sites recovered to 80% of control values. Treatment with 5 mM-chloroquine plus GRP or cycloheximide (10 micrograms/ml) plus GRP demonstrated that the majority of GRP receptors are recycled. NMB and phyllolitorin pretreatment did not influence the subsequent binding of 125I-GRP, suggesting that these peptides do not down-regulate GRP receptors.
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PMID:Characterization of ligand binding and processing by gastrin-releasing peptide receptors in a small-cell lung cancer cell line. 131 3

The purpose of this study was to examine whether neutral endopeptidase and angiotensin I-converting enzyme, two membrane-bound metalloenzymes that are widely distributed in the microcirculation, play a role in bradykinin-induced increase in vascular permeability in the hamster cheek pouch. Changes in vascular permeability were quantified by counting the number of leaky sites and by calculating the clearance of fluorescein isothiocyanate (FITC)-dextran (molecular mass, 70,000 d) during suffusion of the cheek pouch with bradykinin. Bradykinin produced a concentration- and time-dependent increase in the number of leaky sites and clearance of FITC-dextran. The selective, active site-directed neutral endopeptidase inhibitors phosphoramidon (1.0 microM) and thiorphan (10.0 microM) and the selective angiotensin I-converting enzyme inhibitor captopril (10.0 microM) each shifted the concentration-response curve to bradykinin significantly to the left. During suffusion with bradykinin (1.0 microM) and phosphoramidon, the number of leaky sites increased significantly from 17 +/- 2 to 27 +/- 4 sites per 0.11 cm2 (mean +/- SEM, p less than 0.05), and FITC-dextran clearance increased significantly from 1.0 +/- 0.2 to 2.1 +/- 0.3 ml/sex x 10(-6).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Role of peptidases in bradykinin-induced increase in vascular permeability in vivo. 131 17

In addition to the cholinergic and adrenergic nervous systems, a new noncholinergic and nonadrenergic nervous system has recently been described, involving the afferent sensory nerves in the airways. Many irritants (dusts, chemicals) stimulate these sensory nerves to release neuropeptides. Among these neuropeptides, the "tachykinins" exist in sensory nerves of airways (substance P, neurokinin A). These tachykinins have the ability to affect multiple cells in the airways and to provoke many responses including smooth muscle contraction, mucus secretion, plasma extravasation and neutrophil adhesion. This series of effects is termed "neurogenic inflammation". Using the respiratory tract as experimental model, it has been shown that: a) substance P (SP) is widely distributed in afferent fibers in the vagus, b) SP-immunoreactivity has been demonstrated in the epithelium, in airway smooth muscle, near blood vessels and submucosal glands, c) substance P and other tachykinins are released from sensory nerve terminals during stimulation electrically and by capsaicin, d) local administration of substance P mimics the effect of sensory nerve stimulation, e) smooth muscle contraction, gland secretion and plasma leakage, normally induced by nerve stimulation or noxious stimulus, are absent in tissues pretreated with the substance P depleting agent capsaicin or with tachykinin antagonists. These findings indicate that peptidergic nerve fibers are involved in the local regulation of tone of smooth muscle, regulation of blood flow, vascular permeability, and mucus secretion. We released that degradative mechanisms could play an important role in modulating tachykinin effects, just as acetylcholinesterase modulates effects of acetylcholine released from nerve terminals. We discovered that a membrane-bound enzyme called enkephalinase (also called neutral endopeptidase, EC 3, 4, 24, 11), located on specific cells that contain tachykinin receptors, modulate the action of tachykinins by cleaving and thus inactivating them. Our studies demonstrate that viral infection or cigarette smoke potentiate various effects of tachykinins by decreasing tissue enkephalinase activity. Thus, down-regulation of enkephalinase activity in specific tissues can modify the extent of neurogenic inflammation, and this modification could be important in the pathogenesis of diseases in airways and other tissues that contain tachykinins.
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PMID:[The role of enkephalinase (neutral endopeptidase) in neurogenic inflammation of the respiratory tract]. 134 Apr 78

Neutral endopeptidase (NEP; E.C. 3.4.24.11) is a mammalian ectopeptidase identified as the common acute lymphoblastic leukemia antigen (CALLA or CD10). In order to investigate its cellular processing and its role in B lymphocyte differentiation, a fluorescent derivative of the mercapto NEP inhibitor thiorphan, N-[fluoresceinyl]-N'-[1-(6-(3-mercapto-2-benzyl-1-oxopropyl) amino-1-hexyl]thiocarbamide (FTI), has been synthesized. The fluorescent characteristics of fluorescein were conserved in FTI after linkage with the thiol NEP inhibitor. FTI inhibited NEP with an IC50 value of 10 nM and a good selectivity compared to that of aminopeptidase N (greater than 100 microM) and angiotensin converting enzyme (32 microM). The FTI probe was shown to detect membrane-bound NEP using photomicroscopy on cultured cells or flow cytometry techniques. Using NEP-expressing MDCK cells and episcopic fluorescence microscopy, a specific labeling was obtained with 100 nM FTI which was completely displaced by 10 microM HACBOGly, a specific and potent inhibitor of NEP. Therefore, FTI can be considered a suitable tool for following cellular NEP traffic. In flow cytometry, the fluorescent probe FTI, used at concentrations as low as 1 nM with Reh6 cells, could be very useful for detecting NEP/CALLA on lymphoid cells. In addition, the recognition of FTI is independent of tissues and species, a major advantage of inhibitors over monoclonal antibodies.
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PMID:Detection of neutral endopeptidase-24.11/CD10 by flow cytometry and photomicroscopy using a new fluorescent inhibitor. 135 7

The expression of aminopeptidase-N and neutral endopeptidase in human ovarian tissue was examined using specific monoclonal antibodies for each of these peptidases and histochemical staining for enzyme activity. Aminopeptidase-N is a membrane-bound metalloprotease catalyzing the removal of N-terminal amino acids from peptides and was detected by immunofluorescence staining on theca interna cells in secondary follicles and on luteinized thecal cells in preovulatory follicles and corpora lutea. However, aminopeptidase-N was not detected on granulosa cells. Peptidase activity was also detected by histochemical staining on theca interna cells and luteinized thecal cells. Luteinized granulosa cells showed peptidase activity, despite the lack of aminopeptidase-N. Neutral endopeptidase was not detected in ovarian granulosa and thecal cells. These observations indicate that aminopeptidase-N can be a useful surface marker for thecal cells.
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PMID:Differential expression of aminopeptidase-N on human ovarian granulosa and theca cells. 137 Jan 66

A membrane-bound metallo-endopeptidase that hydrolyzes human parathyroid hormone (1-84) and reduced hen egg lysozyme between hydrophilic amino acid residues was isolated from rat kidney [Yamaguchi et al. (1991) Eur. J. Biochem. 200, 563-571]. In this study, the hydrolyses of various peptide hormones and neuropeptides by the metallo-endopeptidase were examined using an automated gas-phase protein sequencer. The purified enzyme hydrolyzed the oxidized insulin B chain and substance P most rapidly, followed by big endothelin 1, neurotensin, angiotensin 1, endothelin 1, rat alpha-atrial natriuretic peptide and bradykinin, in this order. The enzyme mainly cleaved these peptides at bonds involving a hydrophilic amino acid residue. However, it cleaved bonds between less hydrophilic amino acid pairs in several short peptides, e.g. at the His5-Leu6 bond in oxidized insulin B chain, the Ile28-Val29 bond in big endothelin-1 and the Ile5-His6 and Phe8-His9 bonds in angiotensin 1. The enzyme cleavage sites of oxidized insulin B chain and angiotensin 1 were different from the reported sites cleaved by meprin and by endopeptidase 2, respectively. Kinetic determination of bradykinin hydrolysis by the purified enzyme yielded values of Km = 18.1 microM and kcat = 0.473 s-1, giving a ratio of kcat/Km = 2.62 x 10(4) s-1.M-1. The Km value was about 20-fold lower than that reported for meprin and endopeptidase 2. These results indicate that the membrane-bound metallo-endopeptidase from rat kidney is distinguished from meprin and endopeptidase 2 in its substrate specificity and is not parathyroid hormone specific, but has potential capacities to inactivate various biologically active peptide hormones and neuropeptides in vivo.
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PMID:A membrane-bound metallo-endopeptidase from rat kidney. Characteristics of its hydrolysis of peptide hormones and neuropeptides. 137 51

The purpose of this study was to determine whether substance P (SP), neurokinin A (NKA), and neurokinin B (NKB) induce the release of neutrophil chemotactic activity (NCA) from bovine bronchial epithelial cells (BBEC) and whether neutral endopeptidase (NEP), a membrane-bound metalloenzyme that hydrolyzes tachykinins, modulates these effects. BBEC monolayers were exposed to SP, NKA, and NKB in the absence or presence of phosphoramidon (10(-6) M), a selective NEP inhibitor, for 72 h. Using a modified blind-well in vitro neutrophil chemotaxis assay, we found that tachykinin-exposed BBEC culture supernatant fluids induced significant neutrophil chemotaxis compared with supernatants obtained from unstimulated BBEC. Maximal effect was observed after 48 h of incubation and at SP concentration of 10(-13) M [92 +/- 3 (SP) vs. 64 +/- 2 (media) cells/high-power field (HPF), mean +/- SE, n = 7, P less than 0.05]. Release of NCA was mediated by the COOH-terminal of the SP molecule. The rank order of potency of tachykinins in inducing release of NCA was SP greater than NKA = NKB. SP-induced response was significantly potentiated by phosphoramidon (109 +/- 3 vs. 92 +/- 3 cells/HPF, n = 7, P less than 0.05), whereas other proteinase inhibitors had no effect. The released NCA was composed of protein and lipid-soluble components. These data indicate that mammalian tachykinins induce the release of NCA from BBEC and that NEP modulates these effects. We suggest that tachykinins regulate neutrophil recruitment into the lower respiratory tract, in part, by inducing the release of NCA from airway epithelial cells.
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PMID:Bronchial epithelial cells release neutrophil chemotactic activity in response to tachykinins. 138 Nov 52

Aminopeptidase activities were identified in extracts of kidney, ovotestis, head ganglia, heart and haemolymph of Aplysia californica. These enzyme preparations hydrolysed [3H][Leu]enkephalin at the Try-1-Gly-2 bond as determined by h.p.l.c. analysis of cleavage products. In all these tissues, enkephalin-degrading aminopeptidase activities were present both in membrane-bound and cytosolic fractions. The bivalent-cation-chelating agent, 1,10-phenanthroline, inhibited kidney membrane aminopeptidase activity with an IC50 of 30 microM, suggesting that this enzyme is a metalloproteinase. The aminopeptidase inhibitor amastatin was the most potent inhibitor of [Leu]enkephalin degradation (IC50 25 nM) by membrane-bound aminopeptidase, and bacitracin, bestatin and puromycin were about 100-1000 times less potent. In contrast with membrane-bound aminopeptidase, the cytosolic form is sensitive to puromycin. Angiotensin-converting enzyme inhibitor had no effect on [Leu]enkephalin degradation by kidney membranes, while the neutral endopeptidase inhibitors were poor inhibitors of the enzymes in this preparation. The Km values of the aminopeptidase in the kidney membranes and cytosolic fractions for the [Leu]enkephalin substrate were 2.4 and 7.4 microM respectively. The aminopeptidase present in the kidney membranes also hydrolysed endogenous Phe-Met-Arg-Phe-amide peptide at the Phe-1-Met-2 bond as well as synthetic alanine p-nitroanilide and leucine p-nitroanilide. When used in a competition assay, these substrates inhibited hydrolysis of [3H][Leu]enkephalin, suggesting that the same enzyme degraded all these substrates. Taken together, these results suggest that Aplysia tissues contain both a membrane-bound aminopeptidase related to the mammalian aminopeptidase N and a cytosolic puromycin-sensitive aminopeptidase.
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PMID:Identification and characterization of aminopeptidases from Aplysia californica. 141 57


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