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:1.6.3.1 (NADPH oxidase)
11,281 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Rifapentine (R773, DL473) is a long-acting antituberculous drug used in China. In our experiments we have found some manifestations of induction of hepatic mixed function oxidase system in mice following pretreatment with rifapentine or phenobarbital. Both rifapentine and phenobarbital significantly increased the rate of antipyrine and pentobarbital metabolism in vivo. They also increased liver weight, the content of liver microsomal protein and cytochrome P-450, the activity of NADPH-cytochrome C reductase and NADPH oxidase. SDS-polyacylamide gel electrophoresis showed that the relative proportions of some polypeptide bands in mice microsomal fraction were significantly changed following rifapentine or phenobarbital pretreatment. The results indicate that rifapentine, like phenobarbital, is a potent inducer of hepatic mixed function oxidase system in mice and that it should be used carefully in clinical therapy, when combined with other drugs.
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PMID:Inductive effects of rifapentine on mice hepatic mixed function oxidase system. 231 33

The effect of inositol lipids on the SDS-initiated cell-free activation of NADPH oxidase in membranes of human neutrophils was investigated. In a system consisting of low density membranes, cytosol and SDS, low doses of phosphatidylinositol, phosphatidylinositol mono- and biphosphates and phosphatidic acid interfered with activation of the oxidase. The inhibition was relieved by increasing concentrations of the cytosol. Conversely, preincubation of multilamellar phosphoinositide vesicles with cytosol reduced its ability to support activation of the oxidase.
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PMID:Inositol lipids and phosphatidic acid inhibit cell-free activation of neutrophil NADPH oxidase. 254 71

The superoxide-forming NADPH oxidase of resting macrophages can be activated in a cell-free system by certain anionic amphiphiles, most notably SDS. Activation requires the cooperation of membrane-associated and cytosolic components. We now report that at least two cytosolic factors are required for SDS-elicited activation of NADPH oxidase of guinea pig macrophages. Treatment of cytosol with ammonium sulfate at 37% saturation led to the partition of the two factors in the supernatant and precipitate fractions (termed components sigma 1 and sigma 2, respectively). Although each fraction by itself was inactive, recombining them resulted in complete recovery of the original ability of native cytosol to support SDS-elicited superoxide production by octyl-glucoside solubilized macrophage membranes. Both components are proteins, as shown by their susceptibility to trypsin and proteinase K, and were inactivated by heating at 60 degrees C. sigma 2, but not sigma 1, was inactivated by treatment with the covalent sulfhydryl reagent N-ethylmaleimide. On high-performance gel filtration, sigma 1 was found to have a molecular mass of 30 to 52 kDa, whereas sigma 2 eluted with molecules of 150 to 440 kDa. Component sigma 1 was partially purified from the ammonium sulfate supernatant fraction of cytosol by hydrophobic interaction chromatography followed by gel filtration. A material behaving like sigma 1 was also found to be present in the cytosol of guinea pig thymus cells, lymph node lymphocytes and brain and of the mouse myeloma cell line MOPC 315. However, sigma 2 appears to be strictly phagocyte specific. The molecular characteristics of sigma 1 components from nonphagocytic cells were similar to those of macrophage sigma 1, as shown by their presence in the supernatant, after treatment of cytosol with ammonium sulfate at 37% saturation, a molecular mass close to 30 to 52 kDa and a similar behavior on hydrophobic interaction chromatography. These findings raise the possibility that cytosolic component sigma 1 might be the bearer of a cellular function, more general than the one suggested by its role in the activation of NADPH oxidase of phagocytes.
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PMID:Activation of the superoxide-forming NADPH oxidase of macrophages requires two cytosolic components--one of them is also present in certain nonphagocytic cells. 255 80

The stimulation of O2.- generation by phorbol 12-myristate 13-acetate (PMA) in human neutrophil-derived cytoplasts was inhibited by a variety of phospholipase A2 inhibitors in a concentration-dependent manner. Inhibition was found to be independent of the order of addition of the inhibitor and PMA. The most potent inhibitor, RO 31-4639, inhibited O2.- generation with an IC50 value (concentration causing 50% inhibition) of 1.5 microM. The addition of either arachidonic acid or SDS, in the presence of the inhibitors, was able to restore O2.- generation. The results suggest that arachidonic acid, released by phospholipase A2, is necessary for both the activation and the maintenance of O2.- generation by the NADPH oxidase.
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PMID:Superoxide generation is inhibited by phospholipase A2 inhibitors. Role for phospholipase A2 in the activation of the NADPH oxidase. 255 29

Anionic amphiphiles such as long chain unsaturated fatty acids and SDS were shown to activate the superoxide (O2-) producing NADPH oxidase in a cell-free system derived from sonically disrupted phagocytes (macrophages and granulocytes). O2- production required the cooperation of a membrane associated component sedimenting at 48,000 X g (pi) and a cytosolic factor (sigma). The purpose of the present investigation was to find out whether components pi and sigma were also present in non-phagocytic cells that do not produce O2- when stimulated. It was found that the 48,000 X g pellets of guinea pig lymph node and thymus cell sonicates contained significant amounts of component pi, as shown by their ability to support SDS-elicited NADPH-dependent O2- production when supplemented with macrophage cytosol. Lymph node and thymus pi could be extracted from the membrane by 30 mM octyl glucoside, just as its macrophage-derived equivalent. Combining lymph node and thymus 48,000 X g pellet with autologous cytosol did not yield an active enzyme preparation. Also, cytosol from lymph node and thymus cells could not cooperate with macrophage 48,000 X g pellet, indicating that component sigma was lacking in lymphoid cells. Neither pi nor sigma could be detected in guinea pig kidney, the mouse myeloma cell line MOPC 315 and the canine cell line Cf2Th. The 48,000 X g pellet of all nonphagocytic cells examined contained a b-cytochrome that resembled, by its spectral characteristics, the cytochrome b559 thought to be characteristic of phagocytes. In macrophages, cytochrome b559 represented 80% of b-cytochrome content of the 48,000 X g pellet, whereas in non-phagocytic cells, the equivalent material represented only 50 to 60%. There was no correlation between the presence and quantity of the cytochrome b559-like chromophore in the 48,000 X g pellet of a particular cell type and its ability to cooperate with macrophage cytosol in SDS-elicited O2- production.
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PMID:Certain lymphoid cells contain the membrane-associated component of the phagocyte-specific NADPH oxidase. 283 Dec 70

Highly active superoxide (O2-)-forming NADPH oxidase was extracted from plasmamembranes of phorbol-12-myristate-13-acetate-activated pig neutrophils and was partially purified by gel filtration chromatography. Oxidase activity copurified with cytochrome b-245 in an aggregate containing phospholipids and was almost completely separated from FAD and NAD(P)H-cytochrome c reductase. A polypeptide with molecular weight of 31,500 strictly paralleled the purification of NADPH oxidase, suggesting that it is a major component of the enzyme. The enzyme complex was then dissociated by high detergent and salt concentration and cytochrome b-245 was isolated by a further gel filtration chromatography, with a 147 fold purification with respect to the initial preparation. The cytochrome b-245 showed a 31,500 molecular weight by SDS electrophoresis, indicating that it is actually the component previously identified in the partially purified enzyme. The 31,500 protein was phosphorylated in enzyme preparations from activated but not from resting neutrophils, suggesting that phosphorylation of cytochrome b-245 is involved in the activation mechanism of the O2(-) -forming enzyme responsible for the respiratory burst in phagocytes.
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PMID:Studies on the nature and activation of O2(-)-forming NADPH oxidase of leukocytes. Identification of a phosphorylated component of the active enzyme. 285 Feb 66

Peritoneal macrophages were elicited in rats by using casein as a stimulus; when stimulated with phorbol 12-myristate 13-acetate (PMA) they produced O2.-. Nearly 60% of the total cytochrome b had a low Em,7.0 of -247 mV, typical of the cytochrome b component found in the NADPH-dependent O2(.-)-generating oxidase of neutrophils. The rate of O2.- generation by macrophages was 1.23 mol of O2.-/s per mol of cytochrome b. Treatment of intact macrophages with diphenyleniodonium (DPI) at 0.9 microM caused 50% inhibition of PMA-induced O2.- generation, with little effect on mitochondrial respiratory activity; KCN inhibited respiratory activity without affecting PMA-induced O2.- generation. A similar specificity of inhibition was found for di-2-thienyliodonium (50% inhibition of O2.- generation at 0.5 microM) and, at higher concentrations, for diphenyl iodonium. When macrophage suspensions were incubated with [125I]DPI followed by autoradiography of SDS/polyacrylamide-gel-electrophoresis-separated polypeptides, radioactivity was most strongly associated with a band of Mr 45,000, similar to that found in neutrophils [Cross & Jones (1986) Biochem. J. 237, 111-116]. The O2(.-)-generating oxidase of macrophages appears to have components in common with the NADPH oxidase of neutrophils, despite differences in activity. Its sensitivity to DPI suggests that selective prevention of radical generation by macrophages in vivo is possible.
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PMID:The inhibition by diphenyleneiodonium and its analogues of superoxide generation by macrophages. 303 79

NADPH oxidase was induced in HL-60 human promyelocytic leukemia cells when these cells were treated with 10(-7) M 1,25-dihydroxyvitamin D3 (VD3) for 4 days. The treated cells were disrupted by sonication, and the postnuclear fraction was separated into 48,000 X g supernatant (cytosol) and precipitate (membrane) fractions. Membrane-bound NADPH oxidase was activated in vitro with SDS and cytosol. However, the cytosol from untreated HL-60 cells could not activate NADPH oxidase. The cytosolic activity was induced 2 days after VD3 treatment and fully expressed on day 4. The activity was heat-sensitive and destroyed by trypsin. The possibility that the cytosolic activation factor is a protein kinase C (PKC) was then tested. Ca2+- and phospholipid-dependent PKC activity was low in the cytosol of untreated HL-60 cells but increased in the cytosols of VD3-treated cells 4 and 11 times, respectively, 2 days and 4 days after treatment. H-7 [1-(5-isoquinolinesulfonyl)-2-methylpiperazine dihydrochloride], inhibited PKC activity in a dose-dependent manner at 1-100 microM. Cytosolic activity of NADPH oxidase was not inhibited at all at those concentrations. Furthermore, PKC activity was lost when Ca2+ was omitted from the assay mixture, but NADPH oxidase was activated in the presence of EGTA. These results indicated that the cytosolic factor is not a PKC, and that NADPH oxidase in this cell-free system is activated by a mechanism that does not involve PKC.
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PMID:Induction of cytosolic activation factor for NADPH oxidase in differentiated HL-60 leukemia cells. 316 10

The mechanisms regulating activation of the respiratory burst enzyme, NADPH oxidase, of human neutrophils (PMN) are not yet understood, but protein phosphorylation may play a role. We have utilized a defect in a cytosolic factor required for NADPH oxidase activation observed in two patients with the autosomal recessive form of chronic granulomatous disease (CGD) to examine the role of protein phosphorylation in activation of NADPH oxidase in a cell-free system. NADPH oxidase could be activated by SDS in reconstitution mixtures of cytosolic and membrane subcellular fractions from normal PMN, and SDS also enhanced phosphorylation of at least 16 cytosolic and 14 membrane-associated proteins. However, subcellular fractions from CGD PMN plus SDS expressed little NADPH oxidase activity, and phosphorylation of a 48-kD protein(s) was selectively defective. The membrane fraction from CGD cells could be activated for NADPH oxidase when mixed with normal cytosol and phosphorylation of the 48-kD protein(s) was restored. In contrast, the membrane fraction from normal cells expressed almost no NADPH oxidase activity when mixed with CGD cytosol, and phosphorylation of the 48-kD protein(s) was again markedly decreased. Protein kinase C (PKC) activity in PMN from the two patients appeared to be normal, suggesting that a deficiency of PKC is not the cause of the defective 48-kD protein phosphorylation and that the cytosolic factor is not PKC. These results demonstrate that the cytosolic factor required for activation of NADPH oxidase also regulates phosphorylation of a specific protein, or family of proteins, at 48 kD. Although the nature of this protein(s) is still unknown, it may be related to the functional and phosphorylation defects present in CGD PMN and to the activation of NADPH oxidase in the cell-free system.
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PMID:Coregulation of NADPH oxidase activation and phosphorylation of a 48-kD protein(s) by a cytosolic factor defective in autosomal recessive chronic granulomatous disease. 336 3

Heterogeneity of brewer's yeast old yellow enzyme (OYE) was found by anion-exchange high-performance liquid chromatography (HPLC) as well as by 13C-NMR spectroscopy of [4a-13C]FMN reconstituted into apo OYE. Though the OYE sample prepared according to the conventional procedure gave a single protein band on sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), the OYE sample was found to consist of five species on anion-exchange HPLC. The 13C-NMR spectrum of the [4a-13C]FMN-reconstituted OYE gave multiple peaks corresponding to 4a-13C. This multiplicity indicates that this OYE preparation possesses heterogeneity in the environment surrounding FMN, i.e., the active site of OYE. The different species of OYE were separately obtained by preparative HPLC on an anion-exchange column. These species as well as the unresolved sample showed identical mobility on SDS-PAGE and similar but slightly different NADPH oxidase activities. This heterogeneity was shown not to have resulted from proteolytic modification during the conventional purification procedure, which includes autolysis of the yeast cells, since the enzyme extracted by mechanical destruction of the yeast cells in the presence of various protease inhibitors exhibited identical heterogeneity. The pure OYE forms obtained by preparative anion-exchange HPLC are homogeneous in the flavin environment as revealed by a single 13C-NMR signal for the [4a-13C]FMN-reconstituted species.
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PMID:The heterogeneity of brewer's yeast old yellow enzyme. 351 95


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