Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Hepatic microsomes from rats fed a crude or a purified diet were compared by measureing their contents of protein, cytochrome P-450, and cytochrome b5, their rates of activity of NADPH- and NADH-cytochrome c reductases, NADPH-cytochrome P-450 reductase, NADPH oxidase, lipid peroxidase, ethylmorphine N-demethylase, aniline hydroxylase, benzpyrene hydroxylase, and their substrate-binding spectra (ethylmorphine, hexobarbital, aniline, and ethyl isoyanide). With the exception of lipid peroxidase activity, which was much higher in microsomes from animals fed the crude diet, little or no consistent diet-related differences in these measurements were observed over a 4-week experimental period, nor were results significantly less variable with one or the other diet. No consistent significant differences were observed with two strains of rats. The lower lipid peroxidase activity seen with the purified diet appeared to be due to the high vitamin E intake when that diet was employed; rats fed the crude diet and an oral supplement of alpha-tocopherol yielded microsomes with low lipid peroxidase activities similar to those seen in microsomes from rats fed the purified diet. A gradual temporal increase in benzpyrene hydroxylase activity was observed with both diets. This was interpreted to be due to environment inducing agents other than those present in the diet.
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PMID:Comparison of hepatic microsomal drug-metabolizing systems from rats fed crude and purified diets. 0 25

Cyanide has been shown to stimulate both oxygen uptake and hexose monophosphate shunt activity in phagocytizing human polymorphonuclear leukocytes. It also stimulates the oxidation of NADPH by a particulate fraction derived from phagocytizing cells. This stimulation of NADPH oxidase is not observed in the presence of exogenous Mn2+. Studies with purified enzymes have shown that CN- also stimulates NADPH oxidation by horseradish peroxidase or lactoperoxidase, suggesting that the respiratory burst might be initiated by activation of a peroxidase-like enzyme in the human polymorphonuclear leukocyte. Based on studies of others, however, it does not appear as though the enzyme is identical to myeloperoxidase. The mechanism of the CN- stimulation appears to involve an oxidatic chain reaction, since it stimulates markedly NADPH oxidation in the presence of an artificial superoxide-generating system.
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PMID:Effect of cyanide on NADPH oxidation by granules from human polymorphonuclear leukocytes. 1 79

The oxidative response to phagocytosis by chicken polymorphonuclear leucocytes was investigated as compared to guinea pig polymorphonuclear leucocytes. The polymorphs from both species respond to phagocytosis with an increased oxygen consumption, an increased generation of O2 and H2O2, and an increased oxidation of glucose through the hexose monophosphate shunt. The rate of oxygen consumption, and generation of O2- and H2O2 by phagocytosing chicken polymorphonuclear leucocytes is considerably lower than with phagocytosing guinea pig polymorphonuclear leucocytes. By contrast, the extent of hexose monophosphate shunt stimulation in chicken polymorphs is comparable to that of guinea pig polymorphs. Evidence is presented suggesting that H2O2 is preferentially degraded in chicken cells through the glutathione cycle, whereas catalase and myeloperoxidase are the two main H2O2 degrading enzymes in guinea pig cells. The 20,000 g fraction of the postnuclear supernatant of chicken polymorphs contains a cyanide-insensitive NADPH oxidizing activity which is stimulated during phagocytosis. Similar properties for the NADPH oxidizing activity of guinea pig polymorphs have been previously reported. It is concluded that the metabolic burst of phagocytosing chicken polymorphonuclear leucocytes is qualitatively similar to that of guinea pig polymorphonuclear leucocytes, but the latter cells are more active in all the biochemical parameters that have been measured. The difference in the H2O2 degradation pathways between the two species is accounted for by the lack of myeloperoxidase and catalase in chicken polymorphs.
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PMID:Oxidative metabolism of chicken polymorphonuclear leucocytes during phagocytosis. 3 93

NADPH-cytochrome c reductase (NADPH : ferricytochrome oxido-reductase, EC 1.6.2.4), the flavoprotein which mediates the NADPH-dependent reduction of cytochromes P-450 in adrenocortical microsomes, has been localized immunohistochemically at the light microscopic level in rat adrenal glands. Localization was achieved through the use of sheep antiserum produced against purified, trypsin-solubilized rat hepatic microsomal NADPH-cytochrome c reductase in both an unlabeled antibody peroxidase-antiperoxidase technique and an indirect fluorescent antibody method. The sheep antibody to rat hepatic microsomal NADPH-cytochrome c reductase concomitantly inhibited the NADPH-cytochrome c reductase and progesterone 21-hydroxylase activities catalyzed by isolated rat adrenal microsomes. When sections of rat adrenal glands were exposed to the reductase antiserum in both immunohistochemical procedures, positive staining for NADPH-cytochrome c reductase was observed in parenchymal cells of the three cortical zones but not in medullary chromaffin cells. The intensity of staining, however, was found to differ among the three cortical zones, with the most intense staining being found in the zona fasciculata and the least in the zona glomerulosa. The intensity of staining was also found to differ among cells within the zona fasciculata. These immunohistochemical observations demonstrate that microsomal NADPH-cytochrome c reductase is not distributed uniformly throughout the rat adrenal cortex.
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PMID:Immunohistochemical studies on electron transport proteins associated with cytochromes P-450 in steroidogenic tissues. II. Microsomal NADPH-cytochrome c reductase in the rat adrenal. 10 28

Human adult lung fragments removed from macroscopically undamaged and anthracosis exempted zones of lungs of 20 pneumonectomies made for cancer, were tested for 25 enzymic activities. The location and intensities of these enzymic activities were different in the lung tissue components; The bronchial epithelia contained highly active LDH, MDH, SDH, NADH-TR and NADPH-TR, glucose-6-phosphate dehydrogenase, active hydroxyproline-2-epimerase, alkaline phosphatase. Ca2+-activated ATP-ase, and beta-galactosidase. Bronchial and vascular muscles presented intense activities of LDH, MDH and SDH of alkalinephosphatase, AMP-ase and Ca2+-activated ATP-ase, as well as of beta-galactosidase. The alveolar walls presented high activities of SDH, MDH and LDH, of alkaline and acid phosphatases, of beta-galactosidase and of Tween-40 and 60-esterases, of HEP, cytochrome-oxidase and peroxidase. The free alveolar macrophages were active for LDH, MDH, SDH, NADH-TR and NADPH-TR, G1-6-ph-DH, acid and alkaline phosphatase, cytochrome-oxidase and peroxidase, HEP, AMP-ase and Mg2+-activated ATP-ase, Tween-esterases, naphthol-ASD-acetate esterase, and beta-galactosidase. The endothelia contained high activities of alkaline phosphatase, of AMP-ase and Mg2+-activated ATPase, of LDH, MDH and SDH, and of beta-galactosidase. In bronchial lymphoid nodules it was the LDH, MDH, SDH, cytochrome-oxidase and peroxidase, HEP, alkaline phosphatase and AMP-ase, Tween-60-esterase and beta-galactosidase that were active. The interlobular areas of the lung presented intense activities of SDH, MDH, LDH, HEP and cytochrome-oxidase. The activities of the other tested enzymes were weaker or absent in the adult human lung components, the same as those of aminopeptidases which were present only in some free alveolar macrophages. The discussion of some relationships between these enzymic actitivies and the morphology of the human adult lung tissue asserted that the latter could not be considered as a "normal" tissue but as one overstrained by the components of blood and polluted air.
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PMID:Histoenzymology of the lung. I. Enzyme activities of the lung tissue of acult humans; relationships between structure and functions. 14 Mar 14

The mechanism of steroid hydroxylation in rat liver microsomes has been investigated by employing NaIO4, NaClO2, and various organic hydroperoxides as hydroxylating agents and comparing the reaction rates and steroid products formed with those of the NADPH-dependent reaction. Androstenedione, testosterone, progesterone, and 17beta-estradiol were found to act as good substrates. NaIO4 was by far the most effective hydroxylating agent followed by cumene hydroperoxide, NADPH, NaClO2, pregnenolone 17alpha-hydroperoxide, tert-butyl hydroperoxide, and linoleic acid hydroperoxide. Androstenedione was chosen as the model substrate for inducer and inhibitor studies. The steroid was converted to its respective 6beta-, 7alpha, 15-, and 16alpha-hydroxy derivatives when incubated with microsomal fractions fortified with hydroxylating agent. Evidence for cytochrome P-450 involvement in androstenedione hydroxylation included a marked inhibition by substrates and modifiers of cytochrome P-450 and by reagents which convert cytochrome P-450 to cytochrome P-420. The ratios of the steroid products varied according to the type of hydroxylating agent used and were also modified by in vivo phenobarbital pretreatment. It was suggested that multiple forms of cytochrome P-450 exhibiting different affinities for hydroxylating agent are responsible for these different ratios. Horse-radish peroxidase, catalase, and metmyoglobin could not catalyze androstenedione hydroxylation. Addition of NaIO4, NaClO2, cumene hydroperoxide and other organic hydroperoxides to microsomal suspensions resulted in the appearance of a transient spectral change in the difference spectrum characterized by a peak at about 440 nm and a trough at 420 nm. The efficiency of these oxidizing agents in promoting steroid hydroxylation in microsomes appeared to be related to their effectiveness in eliciting the spectral complex. Electron donors, substrates, and modifiers of cytochrome P-450 greatly diminished the magnitude of the spectral change. It is proposed that NaIO4, NaClO2, and organic hydroperoxides promote steroid hydroxylation by forming a transient ferryl ion (compound I) of cytochrome P-450 which may be the common intermediate hydroxylating species involved in hydroxylations catalyzed by cytochrome P-450.
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PMID:The involvement of cytochrome P-450 in hepatic microsomal steroid hydroxylation reactions supported by sodium periodate, sodium chlorite, and organic hydroperoxides. 17 55

The object of the study was to investigate the occurrence and localization of oxidative enzymes in the redia -- the third larval stage of Fasciola hepatica L. The author detected cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases (diaphorases), as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate, and alcohol dehydrogenases. The presence and localization of the enzymes in various periods of development of the redia were detected with histochemical methods. Out of the studied oxidases and dehydrogenases only cytochrome oxidase was found to be absent from the stages of young rediae. It was ascertained that the redia uses all three paths of release of energy i.e. the glycolytic, Krebs, and pentose cycles, glycolysis being presumably the principal mode of energy production.
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PMID:Oxidative enzymes in the development of Fasciola hepatica L. IV. The activity of oxidases and dehydrogenases in redia. 17 35

The object of the study was the investigation of the occurrence and localization of oxidative enzymes in the 4th and 5th larval stages of the liver fluke, i. e. in the cercaria and metacercaria. The following enzymes were detected: cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases/diaphorases) as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate and alcohol dehydrogenases. The occurrence and localization of the enzymes were investigated histochemically in the cercaria still unreleased from the snail tissues, in the free natatorial cercaria, and in the encysted specimen, i.e. metacercaria. Among the enzymes studied only peroxidase was found to be absent from the cercaria and metacercaria, the latter larva being deprived of alcohol and L-glutamate dehydrogenases as well. The aerobic path, i.e. the Krebs cycle, was ascertained as the principal mode of obtaining energy in the free natatorial cercaria and metacercaria, and glycolysis as the main energy path for the undetached larva. The analysis of the above-mentioned oxidative enzymes was the basis for the description, within the available range, of the function and metabolism of individual organs of cercaria in different periods of its development. In the recapitulation the author discusses the effect of the parasitic way of life of the larval forms of Fasciola hepatica on their energy metabolism.
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PMID:Oxidative enzymes in the development of Fasciola hepatica L. V. Activity of oxidases and dehydrogenases in the Cercaria and Metacercaria. 17 36

Polymorphonuclear leukocytes isolated from chicken peritoneal exudates have been found to catalyze cyanide-insensitive stimulation of respiration and the hexose monophosphate shunt upon exposure to heat-inactivated Staphylococcus aureus. However, there was no demonstrable formate oxidation concomitant with phagocytosis in either the presence or absence of exogenous catalase. Moreover, chicken polymorphonuclear leukocytes failed to oxidize scopoletin concomitant with phagocytosis in the presence of horseradish peroxidase. While oxygen uptake was increased 2- to 3-fold by the stimulus of phagocytosis, the oxidation of [1-(14)C]glucose was increased approximately 20-fold. The cells contain two mechanisms, a glutathione reductase-glutathione peroxidase system and an NADPH-NAD+ transhydrogenase, each of which is present in sufficient capacity to accommodate the enhanced shunt activity. Although chicken polymorphonuclear leukocytes were found to possess a substantial capacity to catalyze the cyanide-insensitive oxidation of either NADH or NADPH, the total or specific activities of such processes were not demonstrably affected by phagocytosis.
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PMID:Chicken neutrophils: oxidative metabolism in phagocytic cells devoid of myeloperoxidase. 17 90

The ability of polymorphonuclear leukocytes (PMN) to produce H(2)O(2) in response to phagocytic stimulation was examined cytochemically using leukocytes from normal individuals and patients with chronic granulomatous disease (CGD). Normal PMN oxidized diaminobenzidine within the phagocytic vacuole by a reaction dependent upon endogenous H(2)O(2) and myeloperoxidase. CGD PMN failed to oxidize diaminobenzidine, which is consistent with the biochemical data showing a lack of H(2)O(2)-generating capacity. A plasma membrane enzyme (oxidase) activated by phagocytosis is capable of H(2)O(2) production in PMN. The localization of this oxidase activity was explored in CGD PMN using a cytochemical technique specific for H(2)O(2). The enzyme activity is stimulated by exogenous NADH, but not NADPH. Reaction product formation, indicative of activity of the oxidase, is dependent upon precipitation of cerium ions by the enzymatically generated H(2)O(2). The advantage of this approach is that enzyme activity of individual cells can be assessed, allowing determination of numbers of reactive cells in the population and their relative degrees of reactivity. NADH oxidase was found to be active both on the plasma membrane and within the phagocytic vacuoles of control PMN, whereas those cells from three CGD patients showed greatly reduced activity in both these sites. Assessment of the reactivity of individual cells showed the number of cells with oxidase activity in CGD to be significantly reduced when compared to control values. Additionally, of those cells that do react, a higher percentage of them are only weakly reactive. Omission of NADH from the incubation medium reduced the percentage of control cells showing enzyme activity but had no effect on CGD PMN, implying that the enzyme is not saturated with substrate in control cells, but in CGD the diminished enzyme is fully saturated. The defect may lie in the fact that in CGD patients there are fewer cells capable of peroxide generation, and a majority of these reactive cells produce only reduced amounts of this bactericidal agent.
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PMID:Hydrogen peroxide production in chronic granulomatous disease. A cytochemical study of reduced pyridine nucleotide oxidases. 19 72


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