Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.4.24.11 (CD10)
9,792 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

In order to further clarify the role of renal kallikrein-kinin (K-K) system in primary aldosteronism (PA), daily urinary excretions of renal K-K system components including kallikrein (KAL), kinin (KIN), total kininase (K-ase), K-ase I, K-ase II and neutral endopeptidase (NEP) were measured in PA and normotensives (NT). In this study, a new method for the simultaneous determination of human urinary K-ase I, II and NEP was established and employed. The daily excretions of KAL was significantly higher in PA than that in NT, while no difference was found in KIN between PA and NT. On the other hand, total K-ase in PA (897 +/- 258 micrograms/min/day) was significantly higher than that in NT (209 +/- 6). NEP was also significantly higher in PA (262 +/- 22 micrograms/min/day) than that in NT (127 +/- 6), whereas there were no differences in K-ase I and K-ase II between PA and NT. The relative contributions of K-ase I, II and NEP to total K-ase in NT were 14, 27 and 59%, while those in PA were 12, 17 and 36%, respectively. As a result, these three K-ase contributed only 64% to the total K-ase in PA. These findings suggested that 1) NEP may play a major role in the catabolism of renal KIN in human, 2) NEP is accelerated in PA, 3) unknown K-ase, different from K-ase I, II or NEP, may exist in PA, and 4) accelerated renal K-ase activity may play some role on the disorder of renal water-sodium metabolism and high blood pressure in PA.
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PMID:Renal kininases in primary aldosteronism. 255 6

We examined the interaction of SC-46542 [des(Phe106, Gly107, Ala115, Gln116)-AP(103-126)], a non-guanylate cyclase-linked atriopeptin (AP) binding site ligand, with thiorphan, an inhibitor of endopeptidase 24.11, on mean arterial pressure, urine flow, urinary sodium excretion and plasma AP immunoreactivity in conscious rats. The coadministration of SC-46542 (16 micrograms/kg/min) and thiorphan (30 mg/kg i.v. bolus) produced a greater diuresis and natriuresis (but had no effect on mean arterial pressure) than administration of either compound alone; plasma APir increased 2-fold during coadministration of SC-46542 and thiorphan (from 325 +/- 46 to 676 +/- 86 pg/ml). Administration of SC-46542 or thiorphan alone had small or no effects on mean arterial pressure, urine flow, urinary sodium excretion or plasma APir. Converting enzyme inhibition did not contribute to the effects of thiorphan since coadministration of captopril plus SC-46542 produced effects similar to SC-46542 alone. When a near threshold infusion of AP(103-126) was combined with the coadministration of SC-46542 and thiorphan, there was a potentiation of the depressor, diuretic and natriuretic responses. Neither SC-46542 nor thiorphan alone had these effects. SC-46542 potentiated the depressor but not diuretic or natriuretic responses to low dose AP(103-126) infusion; thiorphan had little or no effect on the responses to low dose AP(103-126). We conclude that blockade of non-guanylate cyclase-linked AP binding sites with SC-46542 combined with inhibition of AP degradation by endopeptidase 24.11 with thiorphan increases diuresis and natriuresis more than inhibition of either system alone.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Interaction of non-guanylate cyclase-linked atriopeptin receptor ligand and endopeptidase inhibitor in conscious rats. 256 86

An endopeptidase that converts the opioid peptide dynorphin B (Tyr-Gly-Gly-Phe-Leu-Arg-aRg-Gln-Phe-Lys-Val-Val-Thr) to its bioactive fragment Leu-enkephalin-Arg6 was isolated from bovine spinal cord. The enzyme was purified about 230-fold from a concentrated spinal cord extract. Upon sodium dodecyl sulfate-polyacrylamide gel electrophoresis, it stained as a protein of Mr 55,000. The purified enzyme is optimally active at around pH7 and has essential thiol groups. It appears to be highly specific for dynorphin B (Km = 11 microM) but not for alpha-neoendorphin or dynorphin A, two other opioids included in the prodynorphin precursor. From its specificity, molecular size, and inhibitory spectrum, this enzyme is different from other known dynorphin-converting or -degrading enzymes and appears to be a unique and novel endoprotease.
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PMID:A novel bovine spinal cord endoprotease with high specificity for dynorphin B. 256 32

A comprehensive survey of 11 peptidases, all of which are markers for renal microvillar membranes, has been made in membrane fractions prepared from pig choroid plexus. Two fractionation schemes were explored, both depending on a MgCl2-precipitation step, the preferred one having advantages in speed and yield of the activities. The specific activities of the peptidases in the choroid-plexus membranes were, with the exception of carboxypeptidase M, lower than in renal microvillar membranes: those of aminopeptidase N, peptidyl dipeptidase A ('angiotensin-converting enzyme') and gamma-glutamyltransferase were 3-5-fold lower, those of aminopeptidase A and endopeptidase-24.11 were 12-15 fold lower, and those of dipeptidyl peptidase IV and aminopeptidase W were 50-70-fold lower. Carboxypeptidase M had a similar activity in both membranes. Alkaline phosphatase and (Na+ + K+)-activated ATPase were more active in the choroid-plexus membranes. No activity for microsomal dipeptidase, aminopeptidase P and carboxypeptidase P could be detected. Six of the peptidases and (Na+ + K+)-activated ATPase were also studied by immunoperoxidase histochemistry at light- and electron-microscopic levels. Endopeptidase-24.11 and (Na+ + K+)-activated ATPase were uniquely located on the brush border, and the other two peptidases appeared to be much more abundant on the endothelial lining of microvessels. Dipeptidyl peptidase IV and aminopeptidase W were also detected in microvasculature. Pial membranes associated with the brain and spinal cord also stained positively for endopeptidase-24.11, aminopeptidase N and peptidyl dipeptidase A. The immunohistochemical studies indicated the subcellular fractionation did not discriminate between membranes derived from epithelial cells (i.e. microvilli) and those from endothelial cells. The possible significance of these studies in relation to neuropeptide metabolism and the control of cerebrospinal fluid production is discussed.
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PMID:Membrane peptidases in the pig choroid plexus and on other cell surfaces in contact with the cerebrospinal fluid. 265 79

An endopeptidase specific to the Plasmodium falciparum erythrocytic schizont stage and to free merozoites was detected using the fluorogenic GlcA-Val-Leu-Gly-Lys(or Arg)-AEC substrate. The enzyme was purified by high performance liquid chromatography (HPLC); its optimal activity was around pH 7.5 and its isoelectric point was 4.4. The molecular weight of the enzyme was about 68,000, as demonstrated by sodium dodecyl sulfate polyacrylamide gel electrophoresis (SDS-PAGE) under reducing conditions. The endopeptidase was strongly inhibited by thiol proteinase inhibitors, leupeptin, and antipain. The possible involvement of this neutral endopeptidase in the reinvasion process is discussed.
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PMID:Purification and identification of a neutral endopeptidase in Plasmodium falciparum schizonts and merozoites. 266 80

The hydrophilic GH-binding protein of serum is a derivative of the GH receptor. Little is known how this GH binding protein is released from the receptor which is firmly anchored in the plasma membrane. The IM-9 lymphocytes provide a useful laboratory model for studying this process because they are richly endowed with GH receptors and, under special conditions, are able to shed these receptors during incubation. Incubation of IM-9 cells for 90 min at 30 C did not result in the appearance of significant [125I]hGH binding in conditioned medium as determined with an ultrogel AcA 44 minicolumn. When iodoacetamide, 20 mM, or N-ethylmaleimide, 5 mM, was added during incubation, the conditioned medium bound 20-35% of [125I]human(h)GH. p-Chloromercuriphenyl sulfonic acid was less effective in promoting shedding of GH-binding protein. In contrast, aprotinin, phenylmethylsulfonylfluoride (PMSF), bacitracin, leupeptin, pepstatin, phosphoramidon, or chloroquine did not promote release of GH binding protein and did not affect iodoacetamide-induced release. Release was not inhibited by the addition of serum lacking GH binding protein. GH binding protein release was markedly temperature sensitive and practically ceased at 4 C. GH binding protein incubated with [125I] hGH was cross-linked with disuccinimidyl suberate. After sodium dodecyl sulfate-polyacrylamide gel electrophoresis in the presence of dithiothreitol the complex migrated with an estimated molecular weight of 100,000 whereas [125I]hGH cross-linked to the membrane-bound GH receptor of the IM-9 cells migrated with an estimated molecular weight of 135,000. The smaller size of the binding protein is consistent with its derivation from the extracellular domain of the GH receptor. Because the release of this GH binding is greatly augmented by iodoacetamide and N-ethylmaleimide, two known sulfhydryl reactive reagents, we suggest that a free sulfhydryl group, either on the GH receptor or on a neighboring protein normally maintains the integrity of the receptor. The loss of this sulfhydryl group destabilizes the receptor and permits a membrane endopeptidase to release the GH binding protein. Cleavage is not dependent on lysosomal action and is not inhibited by protease inhibitors.
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PMID:Release of growth hormone binding protein from IM-9 lymphocytes by endopeptidase is dependent on sulfhydryl group inactivation. 284 6

1. The L-type Ca2+ current was recorded in guinea-pig ventricular myocytes by the patch clamp technique in the whole-cell configuration. The modification of the current by intracellular application of proteases was studied. 2. During the first phase of action, trypsin, an endopeptidase, increased the amplitude of Ca2+ current about 3-fold. 3. Thereafter, there was a drastic slowing of the inactivation time course of the enhanced Ca2+ current. The half-time of inactivation increased from a control value of about 25 ms to values larger than 200 ms. 4. Cell dialysis with carboxypeptidase A, an exopeptidase, also enlarged the amplitude of Ca2+ current, but did not affect the kinetics of Ca2+ current. Leuaminopeptidase did not modify the Ca2+ current. 5. The hypothesis that Ca2+ channels are affected by the protease is supported by the fact that alterations of the extracellular Na+ or K+ concentration did not influence the modification of the membrane current. Another argument for the involvement of Ca2+ channels is that the modified membrane current could be blocked by inorganic and organic Ca2+ channel blockers (e.g. 10 microM-Cd2+, 100 microM-La3+ or 1 microM-D600). 6. Although the actions of trypsin and maximal concentrations of isoprenaline on the amplitude of the Ca2+ current were not additive, the slowing of inactivation by trypsin occurred independently from beta-adrenergic stimulation. 7. The effect of trypsin on the Ca2+ current could not be blocked by intracellular 5'-adenylyl-imidodiphosphate (AMP-PNP) or Rp-adenosine 3'5'-monothionophosphate (Rp-cAMPS), both of which are known to suppress the cyclic AMP-dependent phosphorylation of the Ca2+ channel. 8. It was concluded that trypsin may directly modify the membrane protein which forms the Ca2+ channel. Since the increment in peak Ca2+ current resembled the action of cyclic AMP-dependent phosphorylation, it may be related to the removal of a 'chemical' inactivation gate which is normally controlled by phosphorylation. The slowing of the time course of Ca2+ current inactivation by trypsin could be due to a modification of the voltage-dependent inactivation gate. Alternatively, the endopeptidase might remove an internal Ca2+ binding site normally responsible for Ca2+-dependent inactivation.
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PMID:Modification of L-type calcium current by intracellularly applied trypsin in guinea-pig ventricular myocytes. 285 49

A nonlysosomal alkaline protease which degrades the oxidatively modified form of Escherichia coli glutamine synthetase has been purified to apparent homogeneity from rat and mouse liver acetone powders. Its molecular weight was determined to be 300,000 by Sephacryl S-300 gel filtration but results of further studies using high pressure liquid chromatography gel filtration suggest a value of 650,000. Examination of the subunit structure by sodium dodecyl sulfate-polyacrylamide gel electrophoresis showed multiple bands of molecular weights between 22,000 and 34,000. The alkaline protease was inhibited by thiol reagents. Phenylmethylsulfonyl fluoride, aprotinin, leupeptin, antipain, and chymostatin partially inhibited the protease. The inhibition by phenylmethylsulfonyl fluoride was prevented by dithiothreitol, and alpha 1-antitrypsin and soybean trypsin inhibitor did not inhibit. No inhibition was observed with metalloprotease inhibitors. The alkaline protease is active over a broad range of pH with optimum activity for the degradation of oxidized glutamine synthetase around pH 9.0. Its activity is not stimulated by MgATP. A study of the products of insulin B chain degradation demonstrated major cleavage sites at Gln13-Ala14, Leu15-Tyr16, Cys(SO3H)19-Gly20, Gln4-His5, and Leu17-Val18. Based on its endopeptidase activity and its inhibitor specificity, the alkaline protease should be classified as a cysteine proteinase. It appears to be distinct from previously described proteinases and is likely involved in nonlysosomal mechanisms of intracellular protein turnover.
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PMID:Purification of a liver alkaline protease which degrades oxidatively modified glutamine synthetase. Characterization as a high molecular weight cysteine proteinase. 286 41

Plasma membrane vesicles were prepared from the basolateral face of pig small intestinal epithelial cells and were enriched in the activity of Na+-K+-ATPase (9-fold relative to the cell homogenate) and ranged in size from 0.15 to 0.40 micron diam. Incubation of somatostatin-14 and [125I-Tyr11]-somatostatin-14 with the vesicles at 37 degrees C resulted in rapid proteolytic degradation of the peptides. Metabolites were isolated by reverse-phase high-performance liquid chromatography and identified by amino acid composition. Cleavages between Ala1-Gly2, Phe6-Phe7, Phe7-Trp8, and Thr10-Phe11 were observed, indicative of aminopeptidase and endopeptidase action. Degradation was inhibited by 1,10-phenanthroline and by bacitracin, and in the presence of these inhibitors and at 21 degrees C binding of [125I-Tyr11]somatostatin-14 to the vesicles was observed. Binding was inhibited in a concentration-dependent manner by somatostatin-14 (half-maximal inhibition at 2.0 +/- 0.1 nM) and by somatostatin-28 (0.8 +/- 0.1 nM) but not by structurally unrelated peptides. The rate of degradation of [125I-Leu8, D-Trp22, Tyr25]somatostatin-28 by basolateral membrane was less than 20 fold that of [125I-Tyr11]somatostatin-14 and a two- to three-fold enhanced binding to the vesicles was observed. Analysis of the inhibition of binding of this analogue by somatostatin-28 indicates the presence of single class of binding site with Kd = 1.3 +/- 0.3 nM. Rapid degradation but no specific binding of somatostatin-14 by brush-border membranes was observed.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Specific binding and degradation of somatostatin by membrane vesicles from pig gut. 287 63

We investigated the ability of human T cells to be directed to lyse murine and human tumor targets by antibodies (Ab) to the T11-E rosette (CD2) receptor. We found that the human cytotoxic T lymphocyte clone TBI-6, which is specific for the Epstein-Barr virus-transformed cell line, CM-EBV, could be directed to lyse the Fc receptor-positive murine tumor P388D1, by the combination of anti-T11(2) plus anti-T11(3) Ab. This activation and lysis was demonstrable only with an Fc receptor expressing tumor target and only with those Ab or with anti-T3 (CD3) Ab but not with other anti-T11 Ab or other Ab directed against surface structures on the clone. We therefore constructed heterodimeric Ab consisting of anti-T11(2) or anti-T11(3) Ab and the J5 anti-common acute lymphoblastic leukemic antigen (anti-CALLA) Ab. The purity and retained functional properties of the dimers were demonstrated by sodium dodecyl sulfate-polyacrylamide gels, fluorescence-activated cell sorter analysis on relevant cells, and by the ability of these conjugates to activate human peripheral blood lymphocytes to proliferate. These heterodimeric Ab conjugates were shown to be able to direct the lysis of CALLA+ targets by TBI-6. The specificity of this lysis was demonstrated by the inability of these heterodimers to direct the lysis of CALLA- targets by the cytotoxic T lymphocyte clone, and by the ability of excess free J5, but not an irrelevant Ab of the same isotype, to block this type of lysis. The potential clinical significance of these reagents is discussed.
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PMID:Human T cells can be directed to lyse tumor targets through the alternative activation/T11-E rosette receptor pathway. 289 67


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