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:2.7.10.1 (ERK)
95,504 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Melanin-concentrating hormone (MCH) is a cyclic peptide which behaves as an antagonist of the pituitary melanotropic hormone alpha-melanocyte-stimulating hormone in fishes. Cloning of the rat MCH cDNA precursor recently revealed the presence of an additional putative peptide named NEI. The present work examined the susceptibility of these novel peptides to hydrolysis by various purified exo- and endo-peptidases including endopeptidases 24.11 (NEP), 24.15, 24.16, angiotensin-converting enzyme, leucine aminopeptidase and carboxypeptidase A. NEP attacked MCH at three sites of the molecule with an apparent affinity of about 12 microM and a kcat. of 4 min-1. The first site of cleavage was at Cys-7-Met-8, i.e. within the peptide loop formed by the internal disulphide bridge. NEP could therefore be considered as an MCH-inactivating peptidase since the degradation products generated are probably devoid of biological activity. In contrast, NEI neither inhibited the degradation of the NEP chromogenic substrate glutaryl-Phe-Ala-Phe-p-aminobenzoate nor was susceptible to proteolysis by NEP. Unlike NEP, angiotensin-converting enzyme, endopeptidase 24.15 and endopeptidase 24.16 appeared totally unable to cleave MCH, whereas the peptide was readily degraded by aminopeptidase M and carboxypeptidase A.
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PMID:Hydrolysis of rat melanin-concentrating hormone by endopeptidase 24.11 (neutral endopeptidase). 152 Feb 71

Rapid increases in the membrane expression of C3 receptors on granulocytes and monocytes in response to the anaphylatoxin C5a have previously been described. In this study we demonstrate increases in the membrane expression of neutral endopeptidase (NEP, CD10, CALLA), aminopeptidase N (APN, CD13), tyrosine phosphatase (CD45/CD45Ro) and the Fc R Fc gamma-RIII (CD16) on granulocytes within minutes of treatment with human C5a. Monocytes responded to C5a with increases in CD13 and CD45/CD45Ro. These membrane modulations could be prevented by preincubating the C5a preparations with anti-C5a mAb C17/5 but not by pretreating the cells with cycloheximide. Increases of CD10, CD13, and CD11b but not CD11a (LFA-1) were also observed in leukocytes from patients undergoing hemodialysis with cuprophan membranes. The increase of CD16 on granulocytes was dependent on the presence of plasma during in vitro activation with C5a indicating that plasma contains inhibitors which prevent the previously described loss of Fc gamma-RIII upon stimulation of the cells.
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PMID:Rapid increases in the membrane expression of neutral endopeptidase (CD10), aminopeptidase N (CD13), tyrosine phosphatase (CD45), and Fc gamma-RIII (CD16) upon stimulation of human peripheral leukocytes with human C5a. 168 87

We have developed a novel fluorescent histochemical method to localize the enzyme neutral endopeptidase-24.11 (NEP, E.C. 3.4.24.11, enkephalinase) in the rat brain in order to directly compare the relative distributions of the enzyme and its putative peptide substrate, the enkephalins. The method is based on the sequential cleavage of the synthetic peptide substrate, glutaryl-alanyl-alanyl-phenylanyl-4-methoxy-2-naphthylamide, by NEP and exogenous aminopeptidase M to yield free 4-methoxy-2-naphthylamine (MNA). In the presence of nitrosalicylaldehyde, free MNA is captured, yielding an insoluble yellow fluorescent precipitate which marks the site of NEP activity. The specificity of the method was demonstrated using the selective NEP inhibitors thiorphan, phosphoramidon, and JHF26. All NEP staining throughout the brain was abolished using a 50-nM concentration of these inhibitors. The enzyme was richly localized to many regions, including the cerebral cortex, caudate putamen, globus pallidus, hippocampus, substantia nigra, periaqueductal gray, several cranial nerve nuclei, nuclei of the reticular formation of the medulla. In most regions, reaction product was associated with cell bodies of varying size and morphology. In a number of regions, colchicine increased the amount of NEP staining, particularly in cell processes. The regional distribution pattern of the enzyme, however, did not change in response to colchicine and was similar to that of untreated animals. The histochemical localization of NEP was combined with fluorescent immunocytochemical visualization of the enkephalins in order to localize both in the same tissue section. In the globus pallidus, this combined fluorescent technique revealed numerous NEP-positive cell bodies surrounded by fiber pathways displaying intense enkephalin-like immunoreactivity. The source of the NEP in the globus pallidus was studied using the neurotoxic agent, N-methyl-D-aspartate (NMDA). A pronounced decrease in NEP cellular staining was observed within 7 d in response to NMDA, persisted for at least 16 weeks, and correlated with injury of pallidal neurons. There was no apparent change in enkephalin-like immunoreactivity in the globus pallidus in response to NMDA. These data provide evidence that NEP and enkephalin in the globus pallidus derive from different sources. This study supports the hypothesis that NEP localizes to enkephalin-rich regions of the rat brain, and that the enzyme may be involved in the inactivation of synaptically released enkephalins.
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PMID:Histochemical visualization of neutral endopeptidase-24.11 (enkephalinase) activity in rat brain: cellular localization and codistribution with enkephalins in the globus pallidus. 259 7

Recent developments on neutral endopeptidase (NEP, EC 3.4.24.11) are described. These include (1) the development of a novel colorimetric assay with a chromogenic substrate (Glutaryl-Gly-Gly-Phe-2-naphthylamide) coupled with aminopeptidase M (EC 3.4.11.2). (2) A detergent form of the pig kidney enzyme has been purified by immuno-adsorbent chromatography and its molecular properties compared with other forms of the enzyme from rabbit kidney and pig intestine. (3) Rat kidney microvilli contain two endopeptidases of about equal activity when assayed with [125I]iodo-insulin B chain as substrate. One is similar to the rabbit and pig endopeptidases in being sensitive to inhibition by phosphoamidon. The other is insensitive to the inhibitor, though susceptible to chelating agents. The two enzymes are resolvable and have been partially characterized. (4) Endopeptidases of the phosphoramidon-sensitive type are present in various tissues in addition to the principal locations in brush borders of kidney and intestine.
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PMID:Microvillar membrane neutral endopeptidases. 612 11

Respiratory epithelial cell surface neutral endopeptidase 24.11 (NEP-24.11) degrades proinflammatory peptides, and it has been suggested that glucocorticoids may reduce airway inflammation, in part, by upregulation of NEP-24.11. Despite the potential importance of the epithelium as a metabolic barrier, little is known regarding what other peptidases may be present on the epithelial cell surface. Using an immortalized bronchial epithelial cell line (BEAS-2B), we have shown that human epithelial cells express no detectable angiotensin-converting enzyme, carboxypeptidase N, or dipeptidyl(amino)peptidase IV, but express significant levels of aminopeptidase M (AmM), as well as NEP-24.11. The presence of these enzymes was demonstrated via their degradation of biologically active peptides and by flow cytometry. Exposure of cells to the glucocorticoid budesonide (10(-7) M) for up to 5 days did not markedly alter the expression of NEP-24.11 or AmM, as assessed by flow cytometry, nor did glucocorticoid treatment modify rates of peptide hydrolysis by NEP-24.11 or AmM. Thus, BEAS-2B cells have both AmM and NEP-24.11 on their surface, and expression of these enzymes is not altered by glucocorticoids.
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PMID:Glucocorticoids do not alter peptidase expression on a human bronchial epithelial cell line. 751 43

Analysis of SP and NKA metabolism by human vascular endothelium, relative to that in human plasma, identified integrative, multiple pathways for the processing of circulating SP (but not NKA) by angiotensin-converting enzyme (ACE; EC 3.4.15.1), dipeptidyl(amino)peptidase IV (DAP IV; EC 3.4.14.5), and aminopeptidase M (AmM; EC 3.4.11.2). In contrast, SP and NKA, which may diffuse into or be neurally released within the vessel wall, were both metabolized by smooth muscle neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11). Collectively, these studies indicate peptide-specific and site-specific differential processing of SP and NKA by human plasma and vasculature.
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PMID:Metabolism of substance P and neurokinin A by human vascular endothelium and smooth muscle. 752 48

Two anti-nerve growth factor receptor (LNGFR or p75NGFR) antibodies, Me20.4 and Me8211, label stromal cells with dendritic features in fresh smears and in formalin-fixed, paraffin-embedded human bone marrow (BM). The LNGFR+ cells have an oval nucleus, a scanty cytoplasm with long dendrites that intermingle with the hematopoietic cells, line the abluminal side of sinus endothelial cells, and provide the scaffold for the hematopoietic marrow. At the electron microscopy level, the immunogold tag labels the body and the long branching dendrites of fibroblast-like cells with scanty cytoplasm containing mitochondria, endoplasmic reticulum, and dense bodies. The LNGFR+ cells are positive for alkaline phosphatase, reticulin, collagen III, vimentin, TE-7, and CD13 but negative for endothelial (vWF, CD34, Pal-E), neural (CD56, neurofilament) and leukocyte markers (CD45, CD68). The LNGFR+ stromal cells appear in the fetal BM before the hematopoietic activity begins, originate from the vessel adventitia, and radiate in the Bm cavity. Long-term BM culture (LTBMC) in vitro contain LNGFR+ stromal cells. We document the presence of RNA message for the low- (LNGFR) and the high-affinity NGF receptor (NTRK1) by using RT-PCR on fresh BM aspirate and on LTBMC. BM biopsies from patients with hematologic fibrogenic diseases and in cytokine-treated cancer patients are evaluated for LNGFR+ cells: the amount of stained cells is correlated with the traditional reticulin stain in cases of myelofibrosis, therapy-related myelodysplasia, leukemia, and detected an increase of stromal cells in cytokine-treated patients. The anti-LNGFR antibodies represent a specific membrane marker for the adventitial reticular cells (ARC) of the human marrow and allow precise evaluation and quantitation of this important BM microenvironment component in vivo and in vitro.
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PMID:Bone marrow stroma in humans: anti-nerve growth factor receptor antibodies selectively stain reticular cells in vivo and in vitro. 768 1

The chromosomal aberration t(2:5) resulting in the juxtaposition of NPM and ALK genes is a well-known feature of several Ki-1+ anaplastic large cell lymphomas (ALCL) of the T-cell type. However, conflicting results have been reported concerning the presence of this gene rearrangement in other ALCL and Hodgkin's disease (HD), respectively. We performed NPM/ALK RT-PCR on 14 cases of ALCL expressing distinct myelomonocytic markers, e.g. CD11c, CD13, CD14 or CD68, but neither T-cell nor B-cell associated antigens (null cell phenotype). The specific translocation was found exclusively in six childhood tumours previously diagnosed as malignant histiocytosis (MH), whereas all adult lymphomas (three ALCL without characteristics of MH, three secondary ALCL following HD) and two paediatric cases of secondary ALCL following HD did not show NPM/ALK gene fusion products. By Southern blotting, the status of T-cell receptor (TCR) and immunoglobulin heavy chain genes (IgH) were investigated; two patients with initially diagnosed MH had the TCRdelta-chain gene rearranged (Ddelta2-Ddelta3 and Vdelta1-Jdelta1, respectively). IgH rearrangements were detected in only one patient with secondary ALCL. Our data indicate a high association of previously diagnosed MH and NPM/ALK gene rearrangements. In one case, this specific translocation was demonstrated at an early stage of development; in another, a mature TCRdelta-chain gene rearrangement was detected. These data support the hypothesis of a lymphoid origin of this subgroup of Ki-1 positive ALCL previously diagnosed as MH.
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PMID:NPM/ALK gene fusion transcripts identify a distinct subgroup of null type Ki-1 positive anaplastic large cell lymphomas. 861 79

Angiotensin (ANG) and kinin metabolizing enzymes, angiotensin-converting enzyme (ACE; EC 3.4.15.1), neutral endopeptidase-24.11 (NEP-24.11; EC 3.4.24.11), and aminopeptidase M (AmM; EC 3.4.11.2), have recently been identified in a purified skeletal muscle glycoprotein fraction. We have analyzed the cellular localization of these enzymes. In cultured human skeletal muscle adult myoblasts, myotubes, and fibroblasts, kinins and angiotensins were metabolized by NEP-24.11 and AmM but not by ACE. NEP-24.11 degraded ANG II, ANG III. and bradykinin (BK) and converted ANG I to the active metabolite ANG(1-7). ANG III was converted to the novel ANG IV metabolite [des-Arg1]ANG III by AmM. These data suggest that, due to their abundance in the body, skeletal muscle myocytes and fibroblasts may play a major role in modulation of the systemic and local effects of angiotensins and kinins. This role could be particularly important in individuals receiving treatment with ACE inhibitors.
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PMID:Angiotensin and bradykinin metabolism by peptidases identified in cultured human skeletal muscle myocytes and fibroblasts. 874 45

Expression of the CD4 antigen was observed on human fetal liver, fetal bone marrow (BM), and umbilical cord blood progenitors expressing high levels of CD34. Using clonal and liquid-culture assays, CD4+ CD34++ Lin- (lineage = CD3, CD8, CD10, CD14, CD15, CD16, CD19, CD20, and glycophorin A) fetal liver progenitors were found to have a greater proliferative potential than CD4- CD34++ Lin- progenitors, whereas the CD4- fraction was more enriched for erythroid progenitors. Both the CD4+ and the CD4- progenitor subpopulations also gave rise to multilineage engraftment upon transplantation into human fetal bone fragments, supportive of B-lymphoid and myeloid growth, or into human fetal thymic fragments, supportive of T-cell growth, implanted in scid/scid (SCID) mice. However, in SCID-hu mice transplanted with graded doses of donor cells ranging from 2.0 x 10(2) to 2.0 x 10(4) cells, BM reconstitution by the CD4+ fraction of CD34++ Lin- cells was more frequent than by the CD4- fraction when low numbers of cells were injected. These functional data strongly suggest that stem cells reside among CD4+ CD34++ Lin- fetal liver cells. This hypothesis was further supported by the observations that CD4+ CD34++ Lin- fetal liver cells were enriched for CDw90+ (Thy-1), CD117+ (kit), CD123+, HLA-DR+, CD7-, CD38-, CD45RA-, CD71-, CD115- (fms), and rhodamine 123(dull) cells, a phenotypic profile believed to represent fetal stem cells. Furthermore, all CD4+ CD34++ Lin- fetal liver cells also expressed CD13 and CD33.
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PMID:Phenotypic and functional evidence for the expression of CD4 by hematopoietic stem cells isolated from human fetal liver. 902 60


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