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

---

Query: EC:1.11.1.6 (catalase)
55,569 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Xanthine oxidase acting aerobically upon acetaldehyde was found to cause the peroxidation of linolenate. This was demonstrated by increased absorbance at 233 nm due to diene conjugation and by the detection of a lipid peroxide spot on the thin layer chromatograms. 2. Superoxide dismutase inhibited this lipid peroxidation, as did catalase, thus indicating that both O2- and H2O2 were essential intermediates. Scavengers of singlet oxygen also inhibited the peroxidation of linolenate, whereas scavengers of hydroxyl radical did not. These effects, which were observed in the absence of iron salts, led to the proposal that O2- and H2O2 can directly give rise to a singlet oxygen, as follows: O2- + H2O2 leads to OH- + OH. + O2. 3. This proposal was further supported through the use of 2,5-dimethylfuran, as an indicating scavenger of singlet oxygen. Thus, when this compound was exposed to a known source of singlet oxygen, it gave a product which was detectable by thin layer chromatography. This product was also observed when 2,5-dimethylfuran was exposed to the xanthine oxidase system, in which case its accumulation was prevented by superoxide dismutase or by catalase, but not by scavengers of hydroxyl radical.
...
PMID:Superoxide, hydrogen peroxide, and singlet oxygen in lipid peroxidation by a xanthine oxidase system. 17 Dec 66

Human hemoglobin containing cobalt protoporphyrin IX or cobalt hemoglobin has been separated into two functionally active alpha and beta subunits using a new method of subunit separation, in which the -SH groups of the isolated subunits were successfully regenerated by treatment with dithiothreitol in the presence of catalase. Oxygen equilibria of the isolated subunit chains were examined over a wide range of temperature using Imai's polarographic method (Imai, K., Morimoto, H., Kotani, M., Watari, H., and Kuroda, M. (1970) Biochim. Biophys. Acta 200, 189-196). Kinetic properties of their reversible oxygenation were investigated by the temperature jump relaxation method at 16 degrees. Electron paramagnetic resonance characteristics of the molecules in both deoxy and oxy states were studies at 77K. The oxygen affinity of the individual regenerated chains was higher than that of the tetrameric cobalt hemoglobin and was independent of pH. The enthalpy changes of the oxygenation have been determined as -13.8 kcal/mol and -16.8 kcal/mol for the alpha and beta chains, respectively. The rates of oxygenation were similar to those reported for iron hemoglobin chains, whereas those of deoxygenation were about 10(2) times larger. The effects of metal substitution on oxygenation properties of the isolated chains were correlated with the results obtained previously on cobalt hemoglobin and cobalt myoglobin. The EPR spectrum of the oxy alpha chain showed a distinctly narrowed hyperfine structure in comparison with that of the oxy beta chain, indicating that the environment around the paramagnetic center (the bound oxygen) is different between these chains. In the deoxy form, EPR spectra of alpha and beta chains were indistinguishable. These observations suggest that one of the inequivalences between alpha and beta chains might exist near the distal histidine group.
...
PMID:Studies on cobalt myoglobins and hemoglobins. Preparation of isolated chains containing cobaltous protoporphyrin IX and characterization of their equilibrium and kinetic properties of oxygenation and EPR spectra. 18 20

A successive triple introduction of organophosphorus complexon DTPP (sodium-dicalcium salt of diethylene-triaminopentamethylphosphonic acid) in a dose of 500 mg/kg to albino male rats did not produce any marked effect on the composition of the peripheral blood. Some shortening of the initial period in blood coagulation process was noted. DTPP produced a moderate stimulation of the iron-containing enzymes (catalase, peroxidase, cytochroxidase) which led to an increased oxygen consumption. The blood serum and urine potassium, sodium and calcium content did not undergo any significant changes, while the magnesium concentration in the blood serum dropped by 37 pc and in the urine rose by as much as twice as compared to controls. This bears evidence to an elevated discharge of magnesium from the organism following the action of the DTPP complexon.
...
PMID:[Effect of diethylene-triaminopentamethylphosphonic acid complex on various hematologic and biochemical indicators in experimental animals]. 19 88

Low-potential electron acceptors of photosystem I of chloroplast lamellae produce superoxide anions (0-2) and hydrogen peroxide by autoxidation, but have no effect on ethylene formation from methionine; equimolar amounts of ferredoxin are less active in photosynthetic O-2 and H2O2 production but strongly stimulate ethylene production from methionine. 2. Ten to fifty units of superoxide dismutase inhibit fifty to two hundred units of superoxide dismutase stimulate ethylene formation from methionine by chloroplast lamellae in the presence of ferredoxin. This stimulation is stronger at pH 7.0 than at pH 7.8. Catalase inhibits ethylene formation from methionine. 3. Pulse-radiolytic production of nitrite (NO-2) from hydroxylamine, initiated by hydroxyl radicals (.OH) or O-2, shows no difference in the presence or absence of ferredoxin, nor do the decay kinetics of O2. 4. From the above observations and from model reactions (xanthine/xanthine oxidase; iron salts in the presence of H2O2), it is concluded that reduced ferredoxin in the presence of H2O2 forms a Fenton-type oxidizing species for methionine, generating ethylene in the presence of pyridoxal phosphate. 5. Inhibitory effects of both superoxide dismutase and catalase in oxygen-dependent reactions need not necessarily indicate the participation of the 'Haber-Weiss' reaction.
...
PMID:Oxygen activation in isolated chloroplasts. Mechanism of ferredoxin-dependent ethylene formation from methionine. 21 71

The effects of oxidant, pH and ligands on iron- and copper-catalyzed ascorbate oxidation have been examined. The formation of the catalyst-substrate complex is affected by pH, whereas oxidant affects its breakdown. With copper-ion catalysis, ligands inhibit competitively. With iron catalysis, on the other hand, for a series of aminopolycarboxylic ligands at neutral pH, formation of catalyst-substrate is favored by ligands which form more stable iron complexes. Decreased rates caused by changes in metal environment (ligand or pH) may result for competing activities (e.g., catalase activity competing with peroxidase activity). Evidence for a ternary complex (catalyst-substrate-oxidant) is presented.
...
PMID:Kinetics of iron and copper catalysis of ascorbate oxidation. 23 45

Peroxidase from Mycobacterium tuberculosis H37Rv was purified to homogeneity. The homogeneous protein exhibits catalase and Y (Youatt's)-enzyme activities in addition to peroxidase activity. Further confirmation that the three activities are due to a single enzyme was accomplished by other criteria, such as differential thermal inactivation, sensitivity to different inhibitors, and co-purification. The Y enzyme (peroxidase) was separated from NADase (NAD+ glycohydrolase) inhibitor by gel filtration on Sephadex G-200. The molecular weights of peroxidase and NADase inhibitor, as determined by gel filtration, are 240000 and 98000 respectively. The Y enzyme shows two Km values for both isoniazid (isonicotinic acid hydrazide) and NAD at low and high concentrations. Analysis of the data by Hill plots revealed that the enzyme has one binding site at lower substrate concentrations and more than one at higher substrate concentration. The enzyme contains 6g-atoms of iron/mol. Highly purified preparations of peroxidases from different sources catalyse the Y-enzyme reaction, suggesting that the nature of the reaction may be a peroxidatic oxidation of isoniazid. Moreover, the Y-enzyme reaction is enhanced by O2. Isoniazid-resistant mutants do not exhibit Y-enzyme, peroxidase or catalase activities, and do not take up isoniazid. The Y-enzyme reaction is therefore implicated in the uptake of the drug.
...
PMID:The purification and properties of peroxidase in Mycobacterium tuberculosis H37Rv and its possible role in the mechanism of action of isonicotinic acid hydrazide. 24 21

Anaerobically grown Escherichia coli K-12 contain only one superoxide dismutase and that is the iron-containing isozyme found in the periplasmic space. Exposure to oxygen caused the induction of a manganese-containing superoxide dismutase and of another, previously undescribed, superoxide dismutase, as well as of catalase and peroxidase. These inductions differed in their responsiveness towards oxygen. Thus the very low levels of oxygen present in deep, static, aerobic cultures were enough for nearly maximal induction of the manganese-superoxide dismutase. In contrast, induction of the new superoxide dismutase, catalase, and peroxidase required the much higher levels of oxygen achieved in vigorously agitated aerobic cultures. Anaerobically grown cells showed a much greater oxygen enhancement of the lethality of streptonigrin than did aerobically grown cells, in accord with the proposal that streptonigrin can serve as an intracellular source of superoxide. Anaerobically grown cells in which enzyme inductions were prevented by puromycin were damaged by exposure to air. This damage was evidenced both as a decline in viable cell count and as structural abnormalities evident under an electron microscope.
...
PMID:Enzymatic defenses against the toxicity of oxygen and of streptonigrin in Escherichia coli. 32 33

Twenty-three isolates of Achromobacter species (CDC group Vd) were examined morphologically and biochemically. Gram stains revealed gram-variable bacilli frequently curved or hooked at one pole and often coryneform in shape and arrangement. Electron microscopy revealed the presence of extracellular material in polar accumulations and demonstrated the polar flagella arrangement seen by light microscopy to be lateral. Two colony types were produced; one was minute and watery at 24 h (35 degrees C) progressing to large, mucoid colonies at 48 h, and the other type was shiny, glistening, opaque but nonmucoid. All isolates grew on MacConkey agar and produced catalase, oxidase, and urease. Most grew on salmonella-shigella agar, reduced nitrate to nitrite and gas, hydrolyzed esculin, deaminated phenylalanine (2 to 4 days) and produced H2S in triple sugar iron agar (4 to 12 days). Oxidation of carbohydrates was weak, delayed, and limited to glucose and xylose. Two isolates also oxidized maltose, mannitol, and sucrose. The ability of miniaturized "nonfermenter" kits to identify Achromobacter species was tested. The Minitek (Baltimore Biological Laboratory, Cockeysville, Md.) and N/F (Corning, Roslyn, N.Y.) systems, respectively, identified 21 and 19 of the 23 isolates, whereas the Oxi/Ferm (Roche, Nutley, N.J.) identified 13 and the API 20E (Analytab Products, Plainview, N.Y.) identified only 3.
...
PMID:Achromobacter species (CDC group Vd): morphological and biochemical characterization. 37 35

The acceleration of H202 decomposition induced by catalase and the dimer complex [Fe3+(EDTA)]2 has been observed in a constant magnetic field. The effect increases with the field increasing up to 8000 Oe, reaching 20 +/- 5% and 24 +/- 5% for catalase and [Fe3+(EDTA)]2 respectively. The results are discussed within the hypothesis of a one-electron reaction mechanism using the models developed specially to explain the magnetic effects in radical reactions. It is supposed that the stage which is affected by the magnetic field is the electron transfer coupled with Fe3+O./2 paramagnetic species. The interpretation proposed does not exclude an alternative possibility of the magnetic effects during the electron transfer to two iron atoms by a two-electron (synchronous) mechanism.
...
PMID:[Effect of a magnetic field on the rate of H202 breakdown by catalase and by an Fe3+--EDTA complex]. 41 38

The effect of hydrogen peroxide and the mineral limonite on the rate of microbial processes was studied in poor and rich soils. The dynamics of CO2 evolution can be registered upon addition of hydrogen peroxide to chernozem samples, which confirms the existence of metabolism of soil microorganisms. In experiments with desert soil, the evolution of O2 increases rather than that of CO2, which is probably due to an increase in the number of microorganisms producing catalase. Limonite stimulates the metabolic activity of microrganisms. The cultural and morphological properties of microflora are described, which are typical of soils incubated in the presence of limonite and hydrogen peroxide. This work supports the conclusion that, theoretically, the ground of Mars may contain microorganisms which have adapted, in the course of evolution, to high concentrations of hydrogen peroxide and hydrated iron oxides (of the limonite type) in the surrounding medium.
...
PMID:[Effect of hydrogen peroxide and hydrated ferric oxides on the metabolism of soil microflora]. 50 13


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>

---