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Query: UNIPROT:P04040 (Catalase)
 3,577 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Luminol chemiluminescence was observed by addition of menadione to yeast cell suspension and was amplified 1000-fold by further addition of Fe-complex. Catalase, superoxide dismutase and ceruloplasmin had inhibitory effects on luminol chemiluminescence, indicating the extracellular generation of active oxygens (H2O2 and O2-) and reduction of Fe-complex. The generation of H2O2 and reduction of Fe-complex were mainly dependent on the activity of NADH: menadione oxidoreductase in the plasma membrane and cytosol fractions. Both luminol chemiluminescence and H2O2 production were sensitive to the inhibitory effects of proton conductor, ionophorous antibiotics and ATPase inhibitor rather than the inhibitors of the mitochondria electron transport system. The incubation of glucose with yeast cells caused a parallel increase in luminol chemiluminescence, H2O2 production and intracellular NADH concentration. These facts suggest that menadione-catalyzed H2O2 production and chemiluminescence are used as the indicators of cell activity to keep the NADH concentration and NADH: menadione oxidoreductase activity which may be sensitive to the change in pH and ion concentrations.
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PMID:Extracellular generation of active oxygen species catalyzed by exogenous menadione in yeast cell suspension. 187

Microsomal membranes isolated from sugar beet (Beta vulgaris L. var. GWD-2) storage tissue were found to contain a Na3VO4-dependent system for the oxidation of NADH. The system was demonstrated to be enzymatic in nature and specific for Na3VO4. Maximal Na3VO4-dependent NADH oxidation was observed at pH 6.5, when Na3VO4 was present at 200 microM and when NADH was present at 100 microM. The oxidation activity was insensitive to rotenone and antimycin A but was inhibited by NaN3, NaCN, and quinacrine. Sodium vanadate-dependent NADH oxidation occurred with a concomitant uptake of O2 from the assay solution. Both NADH oxidation and O2 consumption were dependent upon the presence of Na3VO4, inhibited by manganese, and preferred NADH to NADPH. Catalase prevented Na3VO4-dependent O2 consumption but accelerated NADH oxidation. The effects of manganese and catalase suggest that superoxide anion and hydrogen peroxide may be involved in this process. While it is unclear as to the physiological significance of Na3VO4-dependent NADH oxidation in plant cells, the presence of this system indicates that caution must be exercised when coupled ATPase assays depending upon NADH oxidation are used with plant membranes in the presence of Na3VO4.
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PMID:Vanadate-dependent NADH oxidation in microsomal membranes of sugar beet. 384 27

Homogenates of the posterior latissimus dorsi muscle, a phasic muscle, were fractionated by a one-step zonal centrifugation technique into four major organelle populations and cytoplasmic constituents. These were: (1) Plasma membrane fragments with a modal equilibrium density of 1.10 and containing 5'-nucleotidase, alkaline phosphodiesterase, p-nitrophenylphosphatase and acid phosphatase (beta-glycerophosphate was used as the substrate). (2) Sarcoplasmic reticular fragments which could be further subdivided into calcium transport vesicles, with a model equilibrium density of 1.16, that exhibited calcium uptake; K+-ATPase; leucyl-bet-naphthylamidase; acid phosphodiesterase; acid phosphatase (using cytidine monophosphate as the substrate); and sarcoplasmic reticular lysosomes, with a model equilibrium density of 1.18, possessing dipeptidyl-aminopeptidase II, cathepsin D, alpha-glucosidase, N-acetyl-beta-glucosaminidase, and NADH oxidase activity. (3) Mitochondria with a modal equilibrium density of 1.21. (4) Catalase-containing vesicles with a modal equilibrium density of 1.22; and cytoplasmic constituents (modal density of 1.25) with phosphorylase, pyruvate kinase, myosin-ATPase, aldolase, and protein and RNA content. The purity of these organelles was equal to or better than previous efforts, with a 30-fold purification achieved for 5'-nucleotidase and alkaline phosphodiesterase. These results lend support to the hypothesis that the sarcoplasmic reticulum of phasic muscle, in addition to its specialized role in excitation-contraction coupling, represents a multifunctional membrane system, and that, similar to the smooth endoplasmic reticulum of other cells, it includes some membrane-bound lysosomal enzymes and NADH oxidase.
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PMID:Isopycnic-zonal centrifugation of plasma membrane, sarcoplasmic reticular fragments, lysosomes, and cytoplasmic proteins from phasic skeletal muscle. 721 87

This study was to investigate the effects of hydrogen peroxide on membrane fluidity and Ca(2+)-ATPase activity of rabbit myocardial sarcoplasmic reticulum (SR). The membrane fluidity of SR was monitored by measuring the changes in the steady state fluorescence anisotropies (rs) using diphenylhexatriene as a probe. The Ca(2+)-ATPase activity was determined by assaying the amount of inorganic phosphate (Pi) released from ATP. It was found that the membrane fluidity (rs: 0.154 +/- 0.014 vs 0.113 +/- 0.010, P < 0.01) and Ca(2+)-ATPase activity (3.1 +/- 1.3 vs 25.3 +/- 2.4 mumol Pi.h-1/mg protein, P < 0.01) were reduced in SR exposed to H2O2 (2 mmol.L-1) for 40 min. Catalase 20 micrograms.ml-1 completely prevented the SR damages caused by H2O2. H2O2 jeopardized the SR in a concentration- and time-dependent manner as measured by changes in rs values and Ca(2+)-ATPase activities, which were negatively correlated (r = 0.981, P < 0.01). These results suggest that H2O2 produces dysfunctions of the rabbit myocardial SR, and that the alteration of membrane fluidity may be one of the mechanisms responsible for the decrease of Ca(2+)-ATPase activity.
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PMID:Effects of hydrogen peroxide on membrane fluidity and Ca(2+)-transporting ATPase activity of rabbit myocardial sarcoplasmic reticulum. 801 24

Artemisinin is an effective antimalarial agent, and its action on the malarial parasite is suggested to be mediated by oxidative processes. Since malarial parasites contain a high concentration of hemin, and hemin may induce the formation of reactive oxygen species, we investigated the interaction of artemisinin, iron and hemin. We used erythrocyte membrane-bound Ca2+ pump ATPase (basal) and calmodulin (CaM)-activated Ca2+ pump ATPase as our model. Membranes were incubated with artemisinin in the presence or absence of iron-ascorbate or hemin at 37 degrees for 1 hr. Following incubation, ATPase activity was measured. Our results showed that artemisinin (500 microM) had no effect on ATPase activities. However, artemisinin enhanced the inhibitory effect of iron (50 microM)-ascorbate (500 microM) on ATPase activity (46.3 +/- 3.9 vs 63 +/- 2.1% for basal; 57.2 +/- 2.5 vs 74.8 +/- 2.1% for CaM-activated). Desferrioxamine (DFO, 200 microM) blocked significantly the effect of iron-ascorbate-artemisinin on ATPases (P < 0.01). Hemin inhibited ATPase activity in a concentration-dependent fashion. Artemisinin enhanced hemin (10 microM)-induced inhibition of basal (36.0 +/- 6.0 vs 73.7 +/- 3.0%) and CaM-activated Ca2+ pump ATPase (31.6 +/- 2.8 vs 70.0 +/- 1.5%). Iron chelators (DFO, ferene, 8-hydroxyquinoline, 1,10-phenanthroline, and 1,2-dimethyl-3-hydroxypyrid-4-one) had no effect on artemisinin plus hemin-induced enzyme inhibition. Catalase (2000 U/mL) had a minor effect on the artemisinin-hemin or hemin-mediated effect. Thiourea (1 mM) had no effect. However, superoxide dismutase (500 U/mL) and dithiothreitol blocked artemisinin-hemin or hemin-mediated ATPase inhibition significantly (P < 0.001). In conclusion, these results suggest that, in our model, artemisinin enhances the damage of hemin-induced ATPases via oxidation of thiol groups on the enzymes. Free iron or hydroxyl radical does not seem to be involved. This interaction between artemisinin and hemin may contribute to the antimalarial action of artemisinin against malarial parasites.
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PMID:Enhancement of hemin-induced membrane damage by artemisinin. 808 Apr 46

Hydrogen peroxide plays an important role in the regulation of iodination and thyroid hormone formation. In the present study, the effect of exogenous H2O2 on 125I transport and organification was investigated in FRTL-5 rat thyroid cells. Less than 20 passages after subcloning, cells in 24-well plates (6 x 10(4) cells/well) were maintained in a thyrotropin (TSH)-containing medium (6H) for 3 days. A TSH-free medium (5H) was then used for the next 7 days. A 1-h exposure to H2O2 stimulated 125I transport and 125I organification at 0.1-0.5 mmol/l H2O2 and had a toxic effect on FRTL-5 cell at 5 mmol/l. Hydrogen peroxide (0.5 mmol/l) augmented the iodide transport and iodine organification induced by TSH (333 U/l) by two- and threefold, respectively. The biphasic effect of H2O2 was blocked totally by 5-200 micrograms/l of catalase. Catalase by itself did not influence TSH-mediated 125I transport and 125I organification. Hydrogen peroxide (0.5 mmol/l) added to cells in 5H medium increased Na+K(+)-ATPase activity twofold. Ouabain (1 mmol/l), an inhibitor of Na+K(+)-ATPase, completely inhibited the twofold increase in 125I transport induced by 0.5 mmol/l H2O2 but only inhibited H2O2-induced 125I organification by 28%. Methimazole (1 mmol/l), an inhibitor of thyroid peroxidase, had no effect on H2O2-mediated 125I transport but totally blocked the fivefold rise in 125I organification induced by 0.5 mmol/l H2O2. The effect of H2O2 on intracellular cyclic adenosine monophosphate (cAMP) levels also was studied.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Effect of exogenous hydrogen peroxide on iodide transport and iodine organification in FRTL-5 rat thyroid cells. 839 14

We have studied the regulation of Na+/K(+)-ATPase function in alveolar type II cells submitted to oxidative stress. Alveolar type II cells were isolated from Sprague Dawley rats and suspended in Dulbecco's modified Eagle's medium. 500 muM xanthine plus 0.5 or 5 mU/ml xanthine oxidase (group 1 and 2, respectively) were added to the cell suspensions. Following various exposure times the reaction was stopped by adding allopurinol and cells were processed to assay H2O2 steady state concentrations, enzymatic activity of catalase and Na+/K(+)-ATPase function. Hydrogen peroxide production by the xanthine-xanthine oxidase system reached maximal values at 30 min of incubation in both groups. H2O2 steady state concentration increased 2- and 10-fold, respectively. Catalase activity was not changed after slight oxidative stress (group 1) but decreased in severe oxidative stress (group 2). Decreases in the Na+/K(+)-ATPase activity (10 and 60% for groups 1 and 2) were found during the first hour of exposure coinciding with the peak in H2O2 steady state concentration. This early inactivation was followed by progressive increases in the activity up to 70% over the control value in group 1, and to the control value in group 2. [3H]Ouabain binding studies showed that the increase in Na+/K(+)-ATPase activity after oxidative stress was due to an increase in the number of phosphorylated pump molecules in the plasma membrane of alveolar type II cells.
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PMID:Hydrogen peroxide increases Na+/K(+)-ATPase function in alveolar type II cells. 864 6

Although in vitro studies have shown that oxygen free radicals depress the sarcolemmal Ca(2+)-pump activity and thereby may cause the occurrence of intracellular Ca2+ overload for the genesis of contractile failure, the exact relationship between changes in sarcolemmal Ca(2+)-pump activity and cardiac function due to these radicals is not clear. In this study we examined the effects of oxygen radicals on sarcolemmal Ca2+ uptake and Ca(2+)-stimulated ATPase activities as well as contractile force development by employing isolated rat heart preparations. When hearts were perfused with medium containing xanthine plus xanthine oxidase, the sarcolemmal Ca(2+)-stimulated ATPase activity and ATP-dependent Ca2+ accumulation were depressed within 1 min whereas the developed contractile force, rate of contraction and rate of relaxation were increased at 1 min and decreased over 3-20 min of perfusion. The resting tension started increasing at 2 min of perfusion with xanthine plus xanthine oxidase. Catalase showed protective effects against these alterations in heart function and sarcolemmal Ca(2+)-pump activities upon perfusion with xanthine plus xanthine oxidase whereas superoxide dismutase did not exert such effects. The combination of catalase and superoxide dismutase did not produce greater effects in comparison to catalase alone. These results are consistent with the view that the depression of heart sarcolemmal Ca2+ pump activities may result in myocardial dysfunction due to the formation of hydrogen peroxide and/or hydroxyl radicals upon perfusing the hearts with xanthine plus xanthine oxidase.
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PMID:Relationship between mechanical dysfunction and depression of sarcolemmal Ca(2+)-pump activity in hearts perfused with oxygen free radicals. 890 72

This study was undertaken to examine if modulations of intracellular and extracellular Ca2+ affect the lethal cell injury and impairment of membrane transport function induced by oxidants in rabbit renal cortical slices. The oxidant t-butylhydroperoxide (t-BHP) and H2O2 increased lactate dehydrogenase (LDH) release and inhibited PAH uptake in a dose-dependent manner, but the potency of H2O2 was 100 times lower than that of t-BHP. Catalase prevented the effect of H2O2 but not that of t-BHP, suggesting that lower potency of H2O2 is attributed to the endogenous catalase activity. t-BHP induced lipid peroxidation and inhibited microsomal (Na+)-(K+)-ATPase activity. Omission of Ca2+ from the medium or addition of Ca2+ channel blockers (verapamil, diltiazem, and nifedipine) prevented the oxidant-induced LDH release. Similar effect was observed by addition of La3+. Buffering intracellular Ca2+ with BAPTA/AM decreased the oxidant-induced LDH release. However, the oxidant-induced impairment in PAH uptake was not altered under the same conditions. Also, the inhibition of microsomal (Na+)-(K+)-ATPase activity by t-BHP was not affected by verapamil, La3+, and BAPTA/AM. Dithiothreitol and glutathione prevented the oxidant-induced LDH release and reduction of PAH uptake and impeded the oxidant-induced inhibition of (Na+)-(K+)-ATPase activity and lipid peroxidation. Effects of t-BHP on TEA uptake were similar to those on PAH uptake. Modulations of intracellular or extracellular Ca2+ had little effect on the oxidant-induced lipid peroxidation. Glycine did not exert protective effect against the oxidant-induced cell injury. These results suggest strongly that Ca2+ plays an important role in the oxidant-induced LDH release but not in the oxidant-induced alterations of membrane transport function in rabbit renal cortical slices. The role of Ca2+ in oxidant-induced LDH release is not apparently associated with peroxidation of membrane lipid.
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PMID:Differential effect of Ca2+ on oxidant-induced lethal cell injury and alterations of membrane functional integrity in renal cortical slices. 897 86

The purpose of this study was to gain direct insights into mechanisms by which myoglobin induces proximal tubular cell death. To avoid confounding systemic and hemodynamic influences, an in vitro model of myoglobin cytotoxicity was employed. Human proximal tubular (HK-2) cells were incubated with 10 mg/ml myoglobin, and after 24 hours the lethal cell injury was assessed (vital dye uptake; LDH release). The roles played by heme oxygenase (HO), cytochrome p450, free iron, intracellular Ca2+, nitric oxide, H2O2, hydroxyl radical (-OH), and mitochondrial electron transport were assessed. HO inhibition (Sn protoporphyrin) conferred almost complete protection against myoglobin cytotoxicity (92% vs. 22% cell viability). This benefit was fully reproduced by iron chelation therapy (deferoxamine). Conversely, divergent cytochrome p450 inhibitors (cimetidine, aminobenzotriazole, troleandomycin) were without effect Catalase induced dose dependent cytoprotection, virtually complete, at a 5000 U/ml dose. Conversely, -OH scavengers (benzoate, DMTU, mannitol), xanthine oxidase inhibition (oxypurinol), superoxide dismutase, and manipulators of nitric oxide expression (L-NAME, L-arginine) were without effect. Intracellular (but not extracellular) calcium chelation (BAPTA-AM) caused approximately 50% reductions in myoglobin-induced cell death. The ability of Ca2+ (plus iron) to drive H2O2 production (phenol red assay) suggests one potential mechanism. Blockade of site 2 (antimycin) and site 3 (azide), but not site 1 (rotenone), mitochondrial electron transport significantly reduced myoglobin cytotoxicity. Inhibition of Na, K-ATPase driven respiration (ouabain) produced a similar protective effect. We conclude that: (1) HO-generated iron release initiates myoglobin toxicity in HK-2 cells; (2) myoglobin, rather than cytochrome p450, appears to be the more likely source of toxic iron release; (3) H2O2 generation, perhaps facilitated by intracellular Ca2+/iron, appears to play a critical role; and (4) cellular respiration/terminal mitochondrial electron transport ultimately helps mediate myoglobin's cytotoxic effect. Formation of poorly characterized toxic iron/H2O2-based reactive intermediates at this site seems likely to be involved.
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PMID:Myoglobin toxicity in proximal human kidney cells: roles of Fe, Ca2+, H2O2, and terminal mitochondrial electron transport. 906 5


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