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)

An isotopic assay for NADPH ixodase that measures the amount of NADP formed by the 6-phosphogluconate dehydrogenase reaction has been developed. Under appropriate conditions, the amount of NADP present is directly proportional to the amount of 14CO2 released from [1-14C]6-phosphogluconic acid. Because this assay employs radioisotopes, it is far more sensitive than conventional assays for the enzyme. The human granule NADPH oxidase, as measured by this assay, is active in the presence of CN minus, is stimulated by Mn-2+, and has a pth optimum of 5.5. Granules isolated from cells that have been allowed to ingest zymosan consistently exhibited more enzyme activity than did granules isolated from either resting cells or cells challenged with zymosan that was not preopsonized. This effect was observed over a wide range of substrate concentrations and could not be explained by differences in protein concentrations between the various samples. If whole homogenates are used in place of isolated granules, the enzyme activity can be observed only with a homogenate of phagocytizing cells and even then only at a high concentration of NADPH. This suggests that an inhibitor of the enzyme might be present within the cell. One patient with chronic granulomatous disease was studied. There was no difference in tnadph oxidase activity of the patients' cells when granules from resting and phagocytizing cells were compared. In contrast, the enzyme activity in granules from two control patients doubled upon phagocytosis. These results are consistent with a role for NADPH oxidase in the initiation of the respiratory burst accompanying phagocytosis by human neutrophils.
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PMID:An isotopic assay for NADPH oxidase activity and some characteristics of the enzyme from human polymorphonuclear leukocytes. 23 61

Peripheral blood leukocytes from patients given corticosteroid or radiation therapy, as well as patients with bacterial or viral infections, were studied with regard to the selected enzyme activities of the hexose monophosphate shunt (HMS). Glucose-6-phosphate dehydrogenase (G-6-PD), 6-phosphogluconate dehydrogenase (6-PGD) and reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase were assayed spectrophotometrically on mixed leukocyte suspensions in isotonic glycerol. Enzyme activities of G-6PD and NADPH oxidase in patients receiving corticosteroid or radiation therapy were significantly lower than the enzyme activity of 6-PGD. In patients with bacterial infections, activities of the three enzymes increased but in patients with viral infections, only the activities of NADPH oxidase and G-6PD were slightly decreased. Nitroblue tetrazolium (NBT) dyereducing activities of neutrophils from patients receiving corticosteroid or radiation therapy were attenuated which coincides with the reduced activities of HMS enzymes. From these results, it is likely that the reduced activities of intraleukocytic HMS enzymes of patients receiving corticosteroid or radiation therapy are correlated with intracellular bactericidal activities which might result from the attenuated level of hydrogen peroxide production.
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PMID:The metabolic and phagocytic activities of leukocytes from patients receiving corticosteroid and radiation therapy, and patients with bacterial infections. 117 10

Radiometric methods for the assay of deoxycorticosterone 11beta-hydroxylase and for the determination of NADP on a microscale were developed. The determination of NADP was based on the quantitative conversion of 6-phospho[1-14C]gluconate to 14CO2 by the action of 6-phosphogluconate dehydrogenase. Using these methods NADPH oxidase activity of the adrenodoxin reductase-adrenodoxin system as well as kinetic properties of deoxycorticosterone 11beta-hydroxylase (cytochrome P-450) were investigated. The NADPH oxidase activity observed in the presence of adrenodoxin reductase, adrenodoxin, and O2, but in the absence of cytochrome P-450 and deoxycorticosterone, were functions of O2 and adrenodoxin concentrations and represented the autooxidation of reduced adrenodoxin which resulted in the production of H2O2. Due to the rapid autooxidizability of reduced adrenodoxin, only a small fraction of electrons conveyed from NADPH to adrenodoxin by way of adrenodoxin reductase was utilized for the deoxycorticosterone 11beta-hydroxylase reaction under the conditions employed.
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PMID:Enzymic studies on adrenocortical deoxycorticosterone 11beta-hydroxylase system. 117 57

The generation of oxygen free radicals (OFR) by peripheral blood monocytes and neutrophils of patients with rheumatic fever (RF) and rheumatic heart disease (RHD) has been studied using the luminol-enhanced chemiluminescence technique. The mechanism of OFR generation was studied by measuring NADPH oxidase enzyme activity. The effect of substrate was studied by measuring the hexose monophosphate (HMP) shunt enzymes: glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Three groups of patients [i) recurrent rheumatic activity, (ii) chronic RHD, (iii) acute pharyngitis) and normal controls were studied at day 0 and followed-up serially at 15, 90 and 180 days. The release of OFR, was significantly higher (P less than 0.001) in patients with recurrent rheumatic activity than in those with acute pharyngitis or chronic RHD, throughout the study period. A significant decline (P less than 0.001) in OFR release was observed from day 0 to day 180 in these patients, whereas no such change was observed in the chronic RHD group. This study raises the possibility that these phagocytic cells, which infiltrate the myocardium, may through generation of OFR, have a role in the pathogenesis of cardiac damage seen in patients with RHD.
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PMID:Release of oxygen free radicals by macrophages and neutrophils in patients with rheumatic fever. 191 47

1. Enzymes pertinent to bactericidal activities of leucocytes were assayed in children suffering from protein-calorie malnutrition. 2. Leucocytes obtained from malnourished and control children contained similar activities for glucose 6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Granule-bound NADPH oxidase activity was low in leucocytes isolated from malnourished patients and failed to show the phagocytic stimulation which is normally seen in control leucocytes. Further, leucocytes obtained from malnourished patients did not release the acid phosphatase from lysosomes during phagocytosis, unlike those from controls. 3. Treatment of the malnourishment with a diet high in calories and protein resulted in significant increase in the activities of glucose 6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase and NADPH oxidase and in releasing the acid phosphatase from the lysosomes into the supernatant fraction during phagocytosis. 4. The significance of these enzyme changes are discussed in relation to the increased susceptibility of these patients to infection.
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PMID:Phagocytosis and leucocyte enzymes in protein-calorie malnutrition. 440 28

The respiratory burst reaction, estimated as O2.- production, has been studied in rat peritoneal macrophages of different age (3, 12 and 24 months). To stimulate NADPH oxidase, the enzyme responsible for the respiratory burst, various stimuli that act in different ways have been used: PMA (phorbol myristate acetate), Con-A (concanavalin A) and N-FMLP (N-formyl-methionyl-leucyl-phenylalanine). All produced a decrease in response with age, with that from PMA being the greatest. The PMA-induced decrease in the O2.- production may be related to the inactivation of NADPH-producing enzymes such as glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase that we have found with age. Glutathione reductase, an enzyme that participates in the maintenance of the redox status in the cell, also showed an age-related decrease. Enzymes that participate in oxygen species scavenging, such as glutathione peroxidase and Cu/Zn superoxide dismutase, did not change with age, although an age-related decrease in catalase activity was found.
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PMID:Respiratory burst reaction changes with age in rat peritoneal macrophages. 821 68

Attachment of Salmonella typhimurium to epithelial surfaces elicit significant alterations in different cell signalling events which lead to the development of disease. The present investigation was conducted to evaluate the effect of immunization of rats with porins, on gut physiologic markers following challenge with S. typhimurium. Male albino Wistar rats were immunized with purified porins and challenged by intragastric infection with S. typhimurium. Electrolyte transport, levels of different second messengers and inflammatory mediators were studied. A net absorption of transepithelial fluxes of Na+ and Cl- in immunized-challenged group and secretion in infected group was found. Ca2+ and 3-O-methyl-D-glucose fluxes did not show any change. Significant increase in the levels of [Ca2+]i, cAMP, membrane form of protein kinase C, prostaglandins, NADPH oxidase, Glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, total oxygen free radicals, reactive nitrogen intermediates, citrulline and lipid peroxidation was found in the infected group. However, in the immunized-challenged group, the values of all the parameters were found to be almost the same as that of control as well as immunized groups. Na+, K+-ATPase and calmodulin levels were unaltered in all the groups of animals. The results of this study thus suggest that immunization of rats with purified Salmonella porins followed by subsequent challenge with the organism might be helpful for the prevention of multiple physiologic derangements in isolated ileal cells.
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PMID:The effect of immunization with porins on gut pathophysiological response in rats infected with Salmonella typhimurium. 1063 Jun 36

The O2*(-) production has been studied in rat peritoneal neutrophils of different age (3, 12 and 24 months), in order to analyse whether the neutrophil respiratory burst is modified with increasing age. To stimulate NADPH oxidase, the enzyme responsible for the respiratory burst, two stimuli that act in different way have been used: phorbol myristate acetate (PMA) and N-formyl-methionyl-leucyl-phenylalanine (N-FMLP). Production of O2*(-) decreased with age in neutrophils stimulated with N-FMLP (about 40%), but not in the stimulated with PMA. No difference in NADPH oxidase activity was found with age. The NADPH is supplied to the respiratory burst mainly by the pentose phosphate shunt. A progressive and significant decrease in the two most important enzymes of this route, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, was detected as a function of age; in spite of this reduction, the NADPH produced by cells from old animals seems not limiting for the O2*(-) production. The N-FMLP-induced decrease in the O2*(-) production may be related to the age-dependent increase in the membrane fluidity observed. A decline in the cholesterol/phospholipid ratio and a rise in the total polyunsaturated fatty acids content were found, that correlated well with the increase in the membrane fluidity. The decrease (50%) of phosphatidylinositols in the 24-month-old animals may be also related to the age-impairment in the respiratory burst found after stimulation with N-FMLP. These studies suggest that the age-related alterations in neutrophil may result in diminished neutrophil function and increased susceptibility to infection in the ageing.
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PMID:Age-related changes in membrane lipid composition, fluidity and respiratory burst in rat peritoneal neutrophils. 1135 47

Neutrophils from pregnant women display reduced neutrophil-mediated effector functions, such as reactive oxygen metabolite (ROM) release. Because the NADPH oxidase and NO synthase produce ROMs and NO, the availability of their substrate NADPH is a potential regulatory factor. NADPH is produced by glucose-6-phosphate dehydrogenase (G-6-PDase) and 6-phosphogluconate dehydrogenase (6-PGDase), which are the first two steps of the hexose monophosphate shunt (HMS). Using immunofluorescence microscopy, we show that 6-PGDase, like G-6-PDase, undergoes retrograde transport to the microtubule-organizing centers in neutrophils from pregnant women. In contrast, 6-PGDase is found in an anterograde distribution in cells from nonpregnant women. However, lactate dehydrogenase distribution is unaffected by pregnancy. Cytochemical studies demonstrated that the distribution of 6-PGDase enzymatic activity is coincident with 6-PGDase Ag. The accumulation of 6-PGDase at the microtubule-organizing centers could be blocked by colchicine, suggesting that microtubules are important in this enzyme's intracellular distribution. In situ kinetic studies reveal that the rates of 6-gluconate turnover are indistinguishable in samples from nonpregnant and pregnant women, suggesting that the enzyme is functionally intact. Resonance energy transfer experiments showed that 6-PGDase and G-6-PDase are in close physical proximity within cells, suggesting the presence of supramolecular enzyme complexes. We suggest that the retrograde trafficking of HMS enzyme complexes during pregnancy influences the dynamics of NADPH production by separating HMS enzymes from glucose-6-phosphate generation at the plasma membrane and, in parallel, reducing ROM and NO production in comparison with fully activated neutrophils from nonpregnant women.
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PMID:6-phosphogluconate dehydrogenase and glucose-6-phosphate dehydrogenase form a supramolecular complex in human neutrophils that undergoes retrograde trafficking during pregnancy. 1512 28

The pathophysiological mechanism of Salmonella enterica subsp. enterica serovar Typhimurium (Salmonella typhimurium) induced gastroenteritis is controlled by interplay of various cell signaling events. Adherence of this organism through type-1 fimbriae is known to be a vital prerequisite for the establishment of infection. In the present investigation male albino Wistar rats were immunized with purified type-1 fimbriae and challenged intragastrically with S. typhimurium. Electrolyte transport and level of different second messengers were studied in four different groups of animals. Transepithelial fluxes of Na+ and Cl- revealed absorption in immunized-challenged group as observed in case of control and immunized group while secretion was observed in infected group. Ca2+ and 3-0-methyl-D-glucose fluxes did not show any change. Significant increase in the level of intracellular Ca2+, cAMP, membrane form of protein kinase C, prostaglandins, NADPH oxidase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, total oxygen free radicals, reactive nitrogen intermediates, citrulline and lipid peroxidation was found in the infected group. However, in the immunized-challenged group, the values of all the parameters were found to be same as that of control as well as immunized groups. Na+, K(+)-ATPase and calmodulin levels were found to be unaltered in all the groups of animals. Thus, the immunization with type-1 fimbriae has been found to be quite effective leading to the prevention of multiple physiologic derangements in isolated ileal cells suggesting the protective role of the fimbriae.
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PMID:The effect of type-1 fimbrial immunization on gut pathophysiological response in rats infected with Salmonella enterica subsp. enterica serovar Typhimurium. 1601 47


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