Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We investigated the effects of H2O2 generated by glucose (G) and glucose oxidase (GO) on the isolated rabbit tracheal smooth muscle suspended in Krebs-Ringer solution. H2O2 generated by G+GO was measured with luminol-dependent chemiluminescence. G+GO in the concentrations of 1x (1.80 microM G, 0.075 U/ml GO) and 2, 4, and 8x generated 1.35, 3.2, 6.10, and 6.00 microM of H2O2, respectively. H2O2 produced relaxation of rabbit tracheal smooth muscle, relaxed acetylcholine (ACh)-precontracted muscle, and reduced muscle responsiveness to ACh. These effects were concentration dependent. H2O2, however, produced contraction of guinea pig tracheal smooth muscle. Catalase completely inhibited the H2O2-induced relaxation of ACh-precontracted tracheal smooth muscle. H2O2-induced relaxation was greater in preparations with intact epithelium (65%) than in those denuded of epithelium (40%). The relaxant effects of H2O2 in the presence of an inhibitor of nitric oxide synthesis (NG-monomethyl-L-arginine), an inhibitor of guanylate cyclase (methylene blue), an inhibitor of cyclooxygenase (indomethacin), and an ATP-sensitive K+ channel blocker (glipizide) were 44, 44, 39, and 48%, respectively. H2O2-induced relaxation in the presence of indomethacin in preparations with denuded epithelium was 29%. These results suggest that H2O2-induced relaxation of tracheal smooth muscle is partly epithelium dependent and is mediated by inhibitory arachidonic acid metabolites, epithelium-derived relaxing factor (nitric oxide), ATP-sensitive K+ channels, and the synthesis and release of prostaglandins from epithelium and the underlying smooth muscle.
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PMID:Mechanism of H2O2-induced modulation of airway smooth muscle. 133 2

Our objective was to determine whether hydroxylamine is a possible intermediate in the oxidative conversion of L-arginine to nitric oxide. Vasorelaxation by hydroxylamine is known to be mediated by nitric oxide. The vasorelaxant properties of hydroxylamine were examined using rat aortic rings and an isolated rat lung perfusion model. Hydroxylamine and acetylcholine were equally effective in relaxing norepinephrine-contracted intact aortic rings, whereas only hydroxylamine relaxed aortic rings with endothelium removed. This endothelium-independent vasorelaxation by hydroxylamine indicated that the hydroxylamine-converting enzyme is not localized solely within endothelial cells. Catalase, an enzyme known to oxidize hydroxylamine to nitric oxide, was present in homogenates of intact and endothelium-denuded rings. Cyanamide, another catalase substrate and a known precursor of nitroxyl (HNO), was not a vasorelaxant of aortic rings or of isolated, hypoxia-constricted lungs. These results suggest that free nitroxyl is not an intermediate in the oxidation of hydroxylamine to nitric oxide. An overall pathway for the oxidative conversion of L-arginine through an hydroxylamine intermediate to nitric oxide is proposed.
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PMID:Hydroxylamine is a vasorelaxant and a possible intermediate in the oxidative conversion of L-arginine to nitric oxide. 250 70

Bovine liver catalase (hydrogen-peroxide:hydrogen peroxide oxidoreductase, EC 1.11.1.6) was derivatized by 9"(10")-[4'-(2-(4,6-dichloro-1,3,5-triazinyl) oxy)butoxy] stearic acid and the fatty acyl-coated enzyme was separated from native catalase and excess reagent by hydroxyapatite chromatography. The derivatization of catalase resulted in coupling the long-chain fatty acyl residues to lysine, histidine and arginine, while other amino acids remained essentially unaffected. The fatty acyl-coated enzyme was water soluble at pH greater than 7.0 but became octanol and ether soluble at pH less than 6.5. The derivatized enzyme retained 50-80% of the catalatic- and peroxidative-specific activities. The free carboxyl function of the coupled long-chain fattyl acyl residues could serve as substrate for ATP-dependent CoA-thioesterification catalyzed by the rat liver microsomal long-chain fatty acyl-CoA synthase.
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PMID:Fatty acyl coupled catalase. 253 62

Previously we have shown that human neutrophils treated with conditioned medium from phytohemagglutinin-stimulated mononuclear leukocytes (sCM) in the presence of antisera have amoebicidal properties for Naegleria fowleri, a pathogenic free-living amoeba. The data now presented show that neutrophils which lack myeloperoxidase (MPO) but have a normal oxygen-dependent respiratory burst could not be altered by sCM to express the amoebicidal activity. Catalase inhibited this amoebicidal activity of sCM-treated neutrophils. Various components and products of the neutrophils were examined for effects on naegleriae. A granule extract was found to have no effect at concentrations up to 100-fold that which killed Salmonella minnesota R595. Hydrogen peroxide appeared to have little effect even at 100 microM. However, in the presence of MPO, H2O2 was amoebicidal at 2.5 microM. The generation of amoebicidal activity required the presence of chloride ions. Azide inhibited the effects of the MPO-H2O2-Cl- system. Arginine, a scavenger of hypochlorite, significantly depressed the ability of sCM-treated neutrophils to kill amoebae and also prevented the amoebicidal properties of the MPO-H2O2-halide system. These results suggest that the MPO-H2O2-halide system is important in the killing of naegleriae by sCM-treated neutrophils and that hypochlorite may be the amoebicidal agent.
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PMID:Role of myeloperoxidase in the killing of Naegleria fowleri by lymphokine-altered human neutrophils. 303 97

Eosinophil peroxidase (donor:hydrogen peroxide oxidoreductase, EC 1.11.1.7) was isolated from outdated human white blood cells. The purified enzyme has a molecular weight of 71000 +/- 1000. The enzyme is composed of two subunits, of Mr 58000 and 14000, in a 1:1 stoichiometry. Amino-acid analyses showed that eosinophil peroxidase has a high content of the amino acids arginine, leucine and aspartic acid. The millimolar absorbance coefficient of the Soret band at 412 nm of eosinophil peroxidase was determined. Three independent methods yield a value for epsilon 412nm of 110 +/- 4 mm-1 X cm-1. Purified eosinophil peroxidase showed a homogeneous high-spin EPR signal with rhombic symmetry (gx = 6.50; gy = 5.40; gz = 1.982) for the haem group. EPR spectroscopy of low-spin cyanide and azide derivatives of eosinophil peroxidase, lactoperoxidase, myeloperoxidase and catalase revealed that the haem-ligand structure of eosinophil peroxidase is closely related to lactoperoxidase, whereas that of myeloperoxidase shows great resemblance to catalase.
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PMID:Some properties of human eosinophil peroxidase, a comparison with other peroxidases. 631 32

The present study intends to define the role of the endothelium derived relaxing factor nitric-oxide (EDRF-NO) and the reactive oxygen intermediates in hypersensitivity to 5-hydroxytryptamine (5-HT) observed in abdominal aorta rings of two kidney-two clip hypertensive rats. Methylene Blue (which blocks production of cGMP by EDRF-NO) and Nw-nitro-L-arginine (which inhibits EDRF-NO synthesis), both shifted 5-HT dose-response curves to the left and completely abolished the differences in sensitivity to the agonist. The aortic perfusion with Krebs-Alcohol 20% (v/v) suppressed vascular relaxation to Ach (10(-5) M) and also abolished differences in sensitivity to 5-HT. These results suggest that a lower availability of EDRF-NO accounts for a higher 5-HT sensitivity in vessels of hypertensive rats. On the contrary, ridogrel (inhibitor of tromboxane-synthase and blocker of PGH2 and TxA2 receptors) did not suppress the hypersensitivity to 5-HT. In addition, since the superoxide anion (O2-) inactivates EDRF-NO, the effects of Superoxide dismutase (SOD) and Catalase (CAT) added in the bath were analyzed. Significant changes in sensitivity (P < 0.005) were found only for vessels of hypertensive rats (SOD depressing and CAT increasing sensitivity to 5-HT). Complementary, SOD activity was evaluated in the aorta homogenates and was found to be significantly lower in the hypertensive rats [(differences between hypertensive and sham rats, mU.mg wet weight tissue-1: 7 days after clipping, -183 +/- 67 (n = 11), P < 0.02; 21 days, -160 +/- 70 (n = 9), p < 0.05]. Results would indicate: 1. Lower EDRF-NO availability in vessels of the hypertensive animals which would account for higher sensitivity to 5-HT; 2. Such a lower EDRF-NO might depend, in part, upon its greater inactivation by O2- anions; 3. A greater presence of O2- anions in the vessels of hipertensive rats that might be favored by the lower SOD activity concentration in the vascular wall.
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PMID:Nitric oxide and superoxide anions in vascular reactivity of renovascular hypertensive rats. 765 50

The production of H2O2 by cells in cold paraformaldehyde-fixed frozen sections of inflammatory lesions was histochemically demonstrated by incubating them with diaminobenzidine (DAB) for 2 to 6 h. Catalase (150 micrograms/ml, about 1400 U/ml) inhibited the reaction, indicating that H2O2 was required to produce the chromogenic DAB product. Granulocytes (PMNs and eosinophils) were the main types of cells stained by the DAB reaction. Positive staining of macrophages was less frequent. The H2O2 was produced by metabolic enzymes that were still active after cell death and mild fixation. An atmosphere of 95 to 100% oxygen enhanced the specific DAB reaction, and an atmosphere of 100% nitrogen eliminated it. The DAB histochemical reaction to detect H2O2 requires the presence of peroxidases to produce the colored reaction product. Within our tissue sections, such peroxidases were evidently present in excess, because addition of low concentrations of H2O2 significantly increased the reaction product. Although some of the H2O2 produced by the granulocytes may have been derived from the dismutation of superoxide (O2-), the NADPH oxidase pathway for O2- formation did not seem to be involved: NADPH oxidase, a rather labile enzyme, should not be active after mild fixation, and diphenyleneiodonium (100 microM), an inhibitor of flavine-requiring NADPH oxidase, did not inhibit the reaction. Reactive nitrogen intermediates were also not involved, because NG-monomethyl-L-arginine and NG-nitro-L-arginine methyl ester, inhibitors of nitric oxide synthetase, did not appreciably inhibit the reaction. We conclude that stable, non-flavine-requiring oxidases, possibly cyclooxygenases or lipoxygenases, produced the H2O2 measured histochemically by our DAB reaction. These studies were made on tissue sections of acute dermal inflammatory lesions produced in rabbits by the topical application of 1% sulfur mustard [bis(2-chloroethyl) sulfide] in methylene chloride. Both intact PMNs and disintegrating PMNs in the base of the crust produced H2O2. Despite the production of H2O2 and the presence of peroxidase activity, no tissue damage was seen microscopically near the H2O2-producing cells, which indicates that the tissues are well protected by the antioxidants present in this self-limiting inflammatory reaction.
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PMID:Histochemical demonstration of hydrogen peroxide production by leukocytes in fixed-frozen tissue sections of inflammatory lesions. 793 Sep 39

1. Small arteries were isolated from either rat mesentery or human subcutaneous fat, and mounted in a myograph for the measurement of isometric force. 2. Superoxide dismutase, either in the presence or absence of catalase, relaxed noradrenaline-induced tone. This effect was abolished by removal of the endothelium or incubation with an inhibitor of NO synthase, N-omega-nitro-L-arginine methyl ester. Catalase alone had a negligible effect on noradrenaline-induced tone. 3. Captopril, an angiotensin-converting enzyme inhibitor and putative free-radical scavenger, did not relax pre-contracted isolated vessels. N-Acetylcysteine caused an endothelium-independent relaxation of rat vessels. Similar effects were observed in human vessels. 4. Acetylcholine induced a concentration-dependent relaxation of isolated resistance arteries, which was inhibited by removal of the endothelium or N-omega-nitro-L-arginine methyl ester, but unaffected by indomethacin. Preincubation with captopril, N-acetylcysteine or catalase alone did not alter the acetylcholine concentration-response relationship, but superoxide dismutase in combination with catalase enhanced responses to acetylcholine, causing a six-fold increase in potency. 5. Superoxide dismutase causes endothelium-dependent relaxation of resistance arteries and potentiates responses to acetylcholine. This action is probably due to the ability of the enzyme to scavenge superoxide anions which inhibit endothelium-dependent relaxation. 6. N-Acetylcysteine causes an endothelium-independent relaxation of resistance arteries which is probably unrelated to the putative ability of this compound to scavenge superoxide radicals and may reflect a direct action on vascular smooth muscle.
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PMID:Free-radical scavengers, thiol-containing reagents and endothelium-dependent relaxation in isolated rat and human resistance arteries. 838 51

Nitric oxide has been implicated in mediating the neurotoxic effects of ischemia in the brain. However, studies of the effects of nitric oxide inhibition with nitric oxide synthase inhibitors have provided controversial results. One of the reasons for the controversy may be related to the specificity of the nitric oxide synthase inhibitors, such as Nw-nitro-L-arginine methylester (L-NAME), which has recently been questioned. The present work investigated the possible interaction of L-NAME with the enzyme catalase in vitro. Catalase is an iron containing enzyme which could potentially interact with the iron-binding groups of L-NAME. Since the normal function of catalase in the brain is to remove excess hydrogen peroxide, the inhibition of this process could have potentially toxic effects. L-NAME was found to attenuate the catalase inhibiting effects of the known catalase inhibitor cyanamide in vitro, suggesting a competition between cyanamide and L-NAME for catalase. In addition, L-NAME by itself attenuated catalase activity in vitro. These results indicate that in addition to inhibiting nitric oxide synthase, L-NAME may have effects on catalase activity.
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PMID:The nitric oxide synthase inhibitor NW-nitro-L-arginine methylester attenuates brain catalase activity in vitro. 861 53

NBXFO hybridoma cells produced both the membrane and secreted isoforms of macrophage colony-stimulating factor (M-CSF). Murine bone marrow cells stimulated by the secreted form of M-CSF (sM-CSF) became Mac1+, Mac2+, Mac3+, and F4/80+ macrophages that inhibited the growth of NBXFO cells, but not L1210 or P815 tumor cells. In cytotoxicity studies, M-CSF activated macrophages and freshly isolated macrophages killed NBXFO cells in the presence of polymyxin B, eliminating the possibility that contaminating lipopolysaccharide (LPS) was responsible for the delivery of the cytotoxic signal. Retroviral-mediated transfection of T9 glioma cells with the gene for the membrane isoform of M-CSF (mM-CSF), but not for the secreted isoform of M-CSF, transferred the ability of macrophages to kill these transfected T9 cells in a mM-CSF dose-dependent manner. Macrophage-mediated killing of the mM-CSF transfected clone was blocked by using a 100-fold excess of recombinant M-CSF. Catalase, superoxide dismutase, and the nitric oxide inhibitor, N-omega-nitro-arginine methyl ester (NAME), did not effect macrophage cytotoxicity against the mM-CSF transfectant T9 clones. T9 parental cells when cultured in the presence of an equal number of the mM-CSF transfectant cells were not killed, indicating specific target cell cytotoxicity by the macrophages. Electron microscopy showed that macrophages were capable of phagocytosizing mM-CSF bearing T9 tumor cells and NBXFO hybridoma cells; this suggested a possible mechanism of this cytotoxicity. This study indicates that mM-CSF provides the necessary binding and triggering molecules through which macrophages can initiate direct tumor cell cytotoxicity.
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PMID:Macrophages can recognize and kill tumor cells bearing the membrane isoform of macrophage colony-stimulating factor. 865 38


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