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)

The origin of luminol-dependent chemiluminescence (CL) in neutrophils stimulated by immune complexes (IC) was investigated. It was found that CL induced by soluble IC and aggregated human gamma globulin (AHG) was glucose-independent, while insoluble IC-induced CL was diminished in the absence of glucose. AHG-induced CL was not inhibited by superoxide dismutase, catalase or 2,5-dimethyl furan, but was suppressed in the presence of phenol, sodium benzoate, sodium formate and mannitol. The CL was also inhibited by inhibitors of arachidonic acid (AA) metabolism including 5,8,11,14-eicosatetraynoic acid, nordihydroguaiaretic acid, quinacrine, indomethacin and aspirin, and by prostaglandins E1 and E2, theophylline and dibutyryl cyclic AMP. Luminol-dependent CL was also studied in cell-free systems including AA plus soybean lipoxygenase, hydroperoxyeicosatetraenoic acid plus peroxidase and xanthine oxidase plus xanthine. Our results indicate that, in neutrophils exposed to soluble IC and AHG, CL is produced and this is closely linked to the formation of free radicals during the metabolism of AA. The radical(s) involved is likely to include the hydroxyl radical. In neutrophils stimulated by large aggregates of IC or micro-organisms, superoxide anion, H2O2 and singlet oxygen are also produced as a result of activation of NAD(P)H oxidase. These oxygen species function as oxidizing agents for AA metabolism and amplify the production of hydroxyl radical along the lipoxygenase (and possibly cyclooxygenase) pathway(s).
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PMID:Luminol-dependent chemiluminescence produced by neutrophils stimulated by immune complexes. 608 70

The effects of 4-weeks ethanol application (20% ethanol, w/w, 2 g X kg-1 on the alcohol oxidizing systems and gluconeogenic enzyme activities of the liver in guinea pigs kept in the cold (+4 degrees C) and at room temperature (+20 degrees C) were studied. The controls were guinea pigs reared at room temperature or in a cold environment without ethanol. The study showed a significant increase (1.5-fold) in liver microsomal cytochrome P-450 after chronic ethanol treatment at room temperature, but not in a cold environment. Microsomal NADPH oxidase activity did not significantly change in any group. Ethanol treatment in a cold environment resulted in a significant increase in liver mitochondrial cytochromes, aa3 and c+c1, and at room temperature in cyt aa3. The activities of total liver homogenate alcohol dehydrogenase or catalase did not change after chronic ethanol treatment. The activity of liver fructose-1.6-diphosphatase showed a significant ethanol induced decrease at room temperature, an effect not observed in the cold environment. Ethanol increased glucose-6-phosphatase activity in the cold, but not at room temperature. In conclusion, the stimulation of liver mitochondrial cytochromes and microsomal cyt P-450 as a consequence of chronic ethanol treatment indicated an increased oxidation capacity for ethanol. The stimulation of glucose-6-phosphatase in a cold environment might be responsible for increasing glucose for heat production after chronic ethanol treatment in cold adapted animals.
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PMID:Liver alcohol oxidizing systems and gluconeogenic enzyme activities after long term ethanol application in cold exposed guinea pigs. 609 47

Kupffer cells were isolated from pronase-perfused rat livers and were maintained as a monolayer culture in a state of high purity and viability. Immediately after contact with zymosan particles, O2 uptake of the Kupffer cells increased fivefold; about 50% of the net oxygen consumed was accounted for as superoxide released into the medium. Concomitantly, a transient burst of luminol-dependent chemiluminescence, an increased activity of NAD(P)H oxidase and a stimulation of the flow of glucose through the hexose monophosphate shunt were observed. Chemiluminescence and O2- production were almost completely inhibited by superoxide dismutase and iodoacetate. Zymosan-induced chemiluminescence was not inhibited in the presence of the non-penetrating thiol reagents, 5,5'-dithio-bis-2-nitrobenzoate and iodoacetyl-sepharose. Iodoacetate acted on the cytosolic glucose-6-phosphate dehydrogenase rather than on NAD(P)H oxidase of the cell membrane.
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PMID:Superoxide release by zymosan-stimulated rat Kupffer cells in vitro. 628 Oct 2

These studies on the effect of administration of 1,600 units of vitamin E to humans indicated the following responses to the PMNs (TABLE 6). Functional alterations occur with an increased ability to ingest particles but a mild decrease in bactericidal potency of the PMN. Although the respiratory burst is slightly enhanced as is superoxide anion release, H2O2 release from the PMN is markedly impaired. The hexose monophosphate shunt activity, which is dependent on intracellular H2O2 is decreased during phagocytosis. Membrane responses such as changes in order parameter during phagocytosis as reported by the stearic acid analogue probe 5DS are similar to those of normal PMNs. The release of arachidonic acid from membranes of vitamin E PMNs during phagocytosis of opsonized zymosan is slightly enhanced, indicating normal phospholipase A2 activation. NADH oxidase-derived H2O2 is not impaired within phagocytic generated by NADPH oxidase in phagocytic vesicles, accounting for impairment in HMPS activity and bactericidal activity in these cells.
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PMID:The influence of vitamin E on human polymorphonuclear cell metabolism and function. 629 63

Phagocytosis by neutrophils is accompanied by a burst in O2 consumption and activation of the hexose monophosphate shunt (HMPS). Proton secretion equal to the amount of O2 consumed is an additional feature of the respiratory burst, but its source has not been identified, nor has the source of all electrons donated to O2 in the respiratory burst. We chemically quantitated total CO2 generation in human neutrophils and found that proton secretion elicited by phagocytosis was accompanied by a stoichiometric increase in CO2 generation. Addition of carbonic anhydrase and its inhibitors had no effect on either the quantities of CO2 measured or the quantities of protons secreted. Therefore, the CO2 generated in the respiratory burst of stimulated neutrophils is hydrated to form H2CO3, which then dissociates, accounting for the observed proton secretion. Furthermore, the CO2 generated corresponds to the O2 consumed with a respiratory quotient of nearly 1. We conclude on the basis of this and previous studies that the HMPS activity is the source of both the electrons for the NADPH oxidase and of protons secreted in association with the respiratory burst.
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PMID:Proton secretion by stimulated neutrophils. Significance of hexose monophosphate shunt activity as source of electrons and protons for the respiratory burst. 643 Sep 61

The luminol-dependent chemiluminescence (CL) of neutrophils phagocytosing zymosan is inhibited by superoxide dismutase (SOD), catalase, sodium benzoate, and 2,5-dimethyl furan. In the present report it is shown that inhibition by SOD and 2,5-dimethyl furan is diminished and removed, respectively, by the omission of glucose from the incubation medium. Zymosan-induced CL is also inhibited by inhibitors of arachidonic acid (AA) metabolism, including 5,8,11,14-eicosatetraynoic acid, nordihydroguaiaretic acid, quinacrine, indomethacin, and aspirin, by prostaglandins E1 and E2, theophylline, and dibutyryl cyclic AMP (cAMP), and by the addition of AA, sodium fluoride, and xanthine oxidase plus xanthine to the cell suspension. These findings lead us to postulate that the metabolism of AA via the lipoxygenase (and cyclooxygenase) pathway(s) is the source of CL observed in neutrophils after phagocytosis. Reactive oxygen species produced as a result of activation of NAD(P)H oxidase provide oxidizing agents for the oxidation of AA along these pathways. It is also suggested that elevated levels of cAMP induced by prostaglandins synthesized via the cyclooxygenase pathway may play a role in the regulation of the zymosan-induced CL response.
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PMID:The origin of chemiluminescence produced by neutrophils stimulated by opsonized zymosan. 668 3

Approved type strains of Streptococcus sanguis, S. mitis, S. mutans, and S. salivarius were grown under aerobic and anaerobic conditions. The rate of hydrogen peroxide excretion, oxygen uptake, and acid production from glucose by washed-cell suspensions of these strains were studied, and the levels of enzymes in cell-free extracts which reduced oxygen, hydrogen peroxide, or hypothiocyanite (OSCN-) in the presence of NADH or NADPH were assayed. The effects of lactoperoxidase-thiocyanate-hydrogen peroxide on the rate of acid production and oxygen uptake by intact cells, the activity of glycolytic enzymes in cell-free extracts, and the levels of intracellular glycolytic intermediates were also studied. All strains consumed oxygen in the presence of glucose. S. sanguis, S. mitis, and anaerobically grown S. mutans excreted hydrogen peroxide. There was higher NADH oxidase and NADH peroxidase activity in aerobically grown cells than in anaerobically grown cells. NADPH oxidase activity was low in all species. Acid production, oxygen uptake, and, consequently, hydrogen peroxide excretion were inhibited in all the strains by lactoperoxidase-thiocyanate-hydrogen peroxide. S. sanguis and S. mitis had a higher capacity than S. mutans and S. salivarius to recover from this inhibition. Higher activity in the former strains of an NADH-OSCN oxidoreductase, which converted OSCN- into thiocyanate, explained this difference. The change in levels of intracellular glycolytic intermediates after inhibition of glycolysis by OSCN- and the actual activity of glycolytic enzymes in cell-free extracts in the presence of OSCN- indicated that the primary target of OSCN- in the glycolytic pathway was glyceraldehyde 3-phosphate dehydrogenase.
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PMID:Hydrogen peroxide excretion by oral streptococci and effect of lactoperoxidase-thiocyanate-hydrogen peroxide. 683 37

The relationship between glucose metabolism and the "respiratory burst" of phagocytosing polymorphonuclear leukocytes (PMN) was studied in a Renex 30-treated cell system of guinea pig PMN by a polarometric technique. Phagocytosing PMN were treated with a detergent (Renex 30) and recovery of respiratory activity was examined by addition of various concentrations of NADP and glucose-6-phosphate (G6P) to determine the availability of endogenously formed NADPH via the hexose monophosphate (HMP) pathway. The oxygen uptake by phagocytosing PMN ceased after the treatment with Renex 30 and was restored by the addition of NADP and G6P. Furthermore, the restoration of oxygen uptake was linearly proportional to the rate of NADPH formation on increase in either NADP or G6P concentration. Resting PMN showed no respiratory activity even in the presence of excess NADP and G6P, in which NADPH was formed at the same rate as in phagocytosing PMN. In a parallel experiment, recovery of respiratory activity was examined in the same system by addition of NAD and glyceraldehyde-3-phosphate (G3P) in that order to clarify whether the respiratory enzyme can utilize NADH formed via the glycolytic pathway. In contrast to the results in the NADPH-forming system, the addition of NAD and G3P induced slight oxygen uptake of Renex 30-treated PMN, but there was no difference in the oxygen uptake between resting and phagocytosis-activated PMN. The results indicated that the primary oxidase responsible for the "respiratory burst" is NADPH oxidase, and that its activity is coupled with glucose oxidation via the HMP pathway without the participation of other metabolic pathways such as glycolysis.
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PMID:Evidence that NADPH is the actual substrate of the oxidase responsible for the "respiratory burst" of phagocytosing polymorphonuclear leukocytes. 687 61

1. The luminol-dependent chemiluminescence of rat thymocytes responding to concanavalin A can be resolved into glucose-dependent and glucose-independent portions. 2. The glucose-dependent portion, supported by D-glucose and D-mannose oxidation, is inhibited by catalase (200 microgram/ml), amobarbital (1 mM) and hexose analogues that block D-glucose uptake. Thus concanavalin A may activate, transiently, an NAD(P)H oxidase that utilizes reducing equivalents derived from the oxidation of exogenous glucose to give dismutation products of O2- (including H2O2) as its major products. 3. The glucose-independent portion is inhibited by eicosa-5,8,11,14-tetraynoic acid but not by indomethacin. It may therefore be associated with the conversion of hydroperoxy intermediates of arachidonic acid metabolism to hydroxy products by the lipoxygenase pathway. 4. Preincubation of thymocytes for 18 h in serum-free medium enhances the subsequent chemiluminescent response to concanavalin A severalfold and evokes the response at a lower threshold concentration. The incorporation of [3H]thymidine by preincubated cells is similarly enhanced at low doses of concanavalin A, whereas the response to optimal doses is unaltered. 5. Catalase does not inhibit the enhanced incorporation of [3H]thymidine obtained in response to concanavalin A, but instead amplifies the response to low doses in the same manner as preincubation.
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PMID:Concanavalin A-induced chemiluminescence in rat thymus lymphocytes. Its origin and role in mitogenesis. 697 84

An in vitro incubation study was conducted to investigate whether increased activity of the polyol pathway in human neutrophils under diabetic conditions resulted in a decrease of superoxide anion produced by NADPH oxidase on the membrane of neutrophils. Lucigenin-enhanced chemiluminescence (CL) to phorbol myristate acetate as respiratory burst and sorbitol levels in neutrophils after incubation with glucose and an aldose reductase (AR) inhibitor, SNK-860 (SNK) were measured. Sorbitol levels increased from 0.210 +/- 0.029 nmol 10(7) cells-1 in 5 mmol l-1 glucose to 0.446 +/- 0.036 nmol 10(7) cells-1 in 40 mmol l-1 glucose, while CL decreased from 0.542 +/- 0.034 cpm cell-1 in 5 mmol l-1 glucose to 0.430 +/- 0.018 cpm cell-1 in 40 mmol l-1 glucose. The addition of 10 mumol l-1 SNK normalized the increased sorbitol levels in neutrophils exposed to 40 mmol l-1 glucose and improved, but did not normalize, the decrease in CL induced by 40 mmol l-1 glucose (p < 0.001). Galactose (40 mmol l-1) also reduced CL, which was improved by the addition of SNK (p < 0.01). These results suggest that impaired respiratory burst induced by high-glucose concentrations is caused by competition for NADPH resulting from increased polyol pathway activity and/or glycation and that an AR inhibitor may be capable in part of preventing increased susceptibility to infection in diabetic patients.
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PMID:Effects of glucose and SNK-860, an aldose reductase inhibitor, on the polyol pathway and chemiluminescence response of human neutrophils in vitro. 764


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