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)

Ca(2+)-loaded rat liver mitochondria treated with 3,5,3'-triiodothyronine (T3) undergo nonspecific inner membrane permeabilization, as evidenced by mitochondrial swelling, a decrease in membrane potential (delta psi), and an increase in the rate of oxygen uptake. T3 analogues thyroxine (T4), 3',5'-diiodothyronine (T2), and 3,5',3'-triiodothyronine (reverse T3), in decreasing order of potency, resulted in a similar but less extensive effect. Permeabilization induced by T3 is dependent on Ca2+ (1 microM) and T3 (0.5-25 microM) concentrations and is inhibited by cyclosporin A, a known inhibitor of mitochondrial permeability transition. Catalase or dithiothreitol also prevents membrane permeabilization, suggesting the participation of membrane protein thiol group oxidation induced by reactive oxygen species. The determination of the mitochondrial membrane protein thiol group content after treatment with Ca2+ and T3 shows a significant decrease, due to thiol oxidation. When mitochondria are incubated in the presence of inorganic phosphate and the protonophore carbonyl cyanide p-trifluoromethoxyphenylhydrazone, mitochondrial swelling still occurs after treatment with T3 and high Ca2+ concentrations, suggesting that mitochondrial permeabilization is not dependent on T3-induced delta psi or matrix pH alterations. Under these experimental conditions, when no oxygen is present in the incubation medium, no permeabilization occurs, suggesting that the permeabilization is dependent on mitochondrial-generated reactive oxygen species. Confirming this hypothesis, superoxide generation in a suspension of submitochondrial particles is increased when T3 is present. Our results lead to the conclusion that T3 induces a situation of oxidative stress in isolated liver mitochondria, with Ca(2+)-mediated membrane protein thiol oxidation and nonspecific inner membrane permeabilization.
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PMID:3,5,3'-triiodothyronine induces mitochondrial permeability transition mediated by reactive oxygen species and membrane protein thiol oxidation. 963 10

The objective of this research was to gain a better understanding of the degree to which recovery of activity of model proteins after freeze-drying can be maximized by manipulation of freeze-dry process conditions in the absence of protective solutes. Catalase, beta-galactosidase and lactate dehydrogenase (LDH) were used as model proteins. All of the three proteins exhibited a concentration-dependent loss of activity after freezing, with significantly higher recovery at higher concentration. The freezing method and the type of buffer were also important, with sodium phosphate buffer and freezing by immersion of vials in liquid nitrogen associated with the lowest recovery of activity. Differential scanning calorimetry was predictive of the onset of collapse during freeze-drying only for beta-galactosidase. For the other proteins, either no Tg' transition was observed, or the apparent glass transition did not correlate with the microscopically-observed collapse temperature. The time course of activity loss for beta-galactosidase and LDH was compared during freeze-drying under conditions which produced collapse of the dried matrix and conditions which produced retention of microstructure in the dried solid. Recovery of activity decreased continuously during primary drying, with no sharp drop in recovery of activity associated with the onset of collapse. The most important drying process variable affecting recovery of activity was residual moisture level, with a dramatic drop in activity recovery associated with residual moisture levels less than about 10%.
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PMID:Effect of process conditions on recovery of protein activity after freezing and freeze-drying. 965 29

Catalase HPII from Escherichia coli is a homotetramer of 753 residue subunits. The multimer displays a number of unusual structural features, including interwoven subunits and a covalent bond between Tyr415 and His392, that would contribute to its rigidity and stability. As the temperature of a solution of HPII in 50 mM potassium phosphate buffer (pH 7) is raised from 50 to 92 degrees C, the enzyme begins to lose activity at 78 degrees C and 50% inactivation has occurred at 83 degrees C. The inactivation is accompanied by absorbance changes at 280 and 407 nm and by changes in the CD spectrum consistent with small changes in secondary structure. The subunits in the dimer structure remain associated at 95 degrees C and show a significant level of dissociation only at 100 degrees C. The exceptional stability of the dimer association is consistent with the interwoven nature of the subunits and provides an explanation for the resistance to inactivation of the enzyme. For comparison, catalase-peroxidase HPI of E. coli and bovine liver catalase are 50% inactivated at 53 and 56 degrees C, respectively. In 5.6 M urea, HPII exhibits a coincidence of inactivation, CD spectral change, and dissociation of the dimer structure with a midpoint of 65 degrees C. The inactive mutant variants of HPII which fold poorly during synthesis and which lack the Tyr-His covalent bond undergo spectral changes in the 78 to 84 degrees C range, revealing that the extra covalent linkage is not important in the enhanced resistance to denaturation and that problems in the folding pathway do not affect the ultimate stability of the folded structure.
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PMID:Catalase HPII from Escherichia coli exhibits enhanced resistance to denaturation. 1019

Aerial oxidation of dopamine at concentrations as low as 50 microM in the presence of ferrous ions in phosphate buffer (pH 7.4) led in the early stages (6-8 h) to the formation of the quinone of the neurotoxin 6-hydroxydopamine, 2, followed (24 h) by a complex product pattern comprising main components norepinephrine (5), 3, 4-dihydroxybenzaldehyde (4), and the neurotoxic alkaloid 6, 7-dihydroxy-1,2,3,4-tetrahydroisoquinoline (3). Product formation required the assistance of metal ions such as Mn(II), Zn(II), and iron, in either the ferrous or ferric form. Product yields were shown to vary linearly with iron and dopamine concentration in the early phases of the reaction (2 h). Biologically relevant antioxidants, like glutathione and ascorbate, and metal chelators, e. g., 2,2'-bipyridyl, inhibited dopamine conversion to products 2-5, but not substrate consumption, while hydroxyl radical scavengers such as DMSO and mannitol did not alter the course of the reaction. On the contrary, mannitol increased product yields, an effect seen for other monosaccharides. Catalase exhibited a significant inhibitory effect particularly on the formation of 3 and 4. By using (18)O(2), evidence was obtained for incorporation of the label into the carbonyl oxygen of 4, but not into the hydroxyl group of 5. On the basis of these and other results, a complete mechanistic picture of the oxidation is drawn involving conversion of dopamine to the corresponding o-quinone and its quinonemethide tautomer with concomitant reduction of O(2) to H(2)O(2). Nucleophilic attack by H(2)O to the quinonemethide gives rise to 5, while H(2)O(2) addition leads to benzaldehyde 4 via a beta-aminohydroperoxide intermediate. This latter reaction path also gives formaldehyde which yields the isoquinoline 3 by Pictet-Spengler condensation with dopamine. The quinone 2 results from H(2)O(2) attack at the 6-position of dopamine o-quinone in agreement with previous studies. These results provide an insight into new routes of nonenzymatic conversion of dopamine to its metabolite norepinephrine and neurotoxic species which may become operative under conditions relevant to neurodegeneration.
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PMID:New reaction pathways of dopamine under oxidative stress conditions: nonenzymatic iron-assisted conversion to norepinephrine and the neurotoxins 6-hydroxydopamine and 6, 7-dihydroxytetrahydroisoquinoline. 1056 35

Catalases are oxidized by singlet oxygen giving rise to more acidic conformers detected in zymograms after electrophoresis in polyacrylamide gels. This shift in catalase mobility can be indicative of singlet oxygen production in vivo. Catalase from human cells, as from many organisms, is susceptible to in vitro modification by singlet oxygen. Human myeloid leukemia (U937) cells were treated under different stress conditions and catalase activity and its electrophoretic mobility was monitored. The U937 cells were found to have high levels of catalase activity, as compared to cultured fibroblasts, and to be very resistant to oxidative stress. Hydrogen peroxide did not modify the electrophoretic mobility of catalase, even at doses that produced cell damage. Conditions that primarily generate superoxide, such as treatment with paraquat or heat shock, also failed to modify the enzyme. In contrast, photosensitization reactions using rose Bengal gave rise to a more acidic conformer of catalase. Singlet oxygen quenchers prevented catalase modification by rose Bengal and light. The growth medium had a photosensitizing activity. Catalase was not modified in cells illuminated in phosphate buffer but was modified in cells illuminated in phosphate buffer containing riboflavin. Intense light per se also generated a slight shift in the electrophoretic mobility of catalase. Ultraviolet light (350 or 366 nm) did cause a change in catalase, but to a less acidic catalase conformer, indicating other modifications of the enzyme. The main effect of photosensitization with methylene blue was crosslinking of the enzyme, although some shift to acidic conformers was observed at a low concentration of the photoactive compound. Results indicate that catalase can be modified by singlet oxygen generated intracellularly, even though the enzyme is predominantly inside peroxisomes. Under some photosensitization conditions, catalase modification can be used as a marker to detect intracellular singlet oxygen.
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PMID:Oxidation of human catalase by singlet oxygen in myeloid leukemia cells. 1062

Catalase (CATpp) with molecular weight 223 kD was isolated from the methylotrophic yeast Pichia pastoris and purified 90-fold by ion-exchange chromatography and gel filtration. Quantitative parameters of absorption and CD spectra of CATpp solutions and of its membrane-concentrated form (CATpp-conc) were studied. Rates of H2O2 decomposition and kinetic characteristics Km and kcat of CATpp and CATpp-conc were determined in 10 mM phosphate buffer (pH 7.4) at 30 degrees C, as well as the effective constant kin of the enzyme inactivation rate during the catalysis and the constant k2 of the interaction rate of the Complex I catalases with H2O2. Thermal inactivation of CATpp in solutions at 45 degrees C was characterized by the effective rate constant kin*, and the low-frequency (27 kHz) ultrasonic inactivation of CATpp at 20 degrees C was characterized by the first-order rate constant kin(US). All spectral and kinetic characteristics of CATpp and CATpp-conc were compared with the corresponding values for catalase from bovine liver (CAT) and for catalase from the methylotrophic yeast Candida boidinii (CATcb). All three catalases were rather similar in their spectral properties but strongly varied in their kinetic parameters, and their comparison suggests that CATpp should be the best enzyme in its overall properties as it displayed the maximal efficiency in terms of kcat/Km, thermal stability comparable with the thermal stability of CAT in terms of kin*, the minimal kin, and high stability in the ultrasonic cavitation field at the US power of 60 W/cm2.
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PMID:Isolation, purification, and characterization of catalase from the methylotrophic yeast Pichia pastoris. 1142 14

The inactivation of glutamine synthetase (GS; EC 6.3.1.2) by metal-catalyzed oxidation (MCO) systems was studied in several Prochlorococcus strains, including the axenic PCC 9511. GS was inactivated in the presence of various oxidative systems, either enzymatic (as NAD(P)H+NAD(P)H-oxidase+Fe(3+)+O(2)) or non-enzymatic (as ascorbate+Fe(3+)+O(2)). This process required the presence of oxygen and a metal cation, and is prevented under anaerobic conditions. Catalase and peroxidase, but not superoxide dismutase, effectively protected the enzyme against inactivation, suggesting that hydrogen peroxide mediates this mechanism, although it is not directly responsible for the reaction. Addition of azide (an inhibitor of both catalase and peroxidase) to the MCO systems enhanced the inactivation. Different thiols induced the inactivation of the enzyme, even in the absence of added metals. However, this inactivation could not be reverted by addition of strong oxidants, as hydrogen peroxide or oxidized glutathione. After studying the effect of addition of the physiological substrates and products of GS on the inactivation mechanism, we could detect a protective effect in the case of inorganic phosphate and glutamine. Immunochemical determinations showed that the concentration of GS protein significantly decreased by effect of the MCO systems, indicating that inactivation precedes the degradation of the enzyme.
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PMID:Regulation of glutamine synthetase by metal-catalyzed oxidative modification in the marine oxyphotobacterium Prochlorococcus. 1178 30

Resistance of Penicillium piceum F-648 to hydrogen peroxide under short-term and prolonged oxidative stress was studied. An increase in the activity of intracellular catalase in fungal cells after short-term exposure to hydrogen peroxide was shown. Activation of fungal cells induced by H2O2 depends on H2O2 concentration, time of exposure, and the growth phase of the fungus. Variants of P. piceum F-648 that produced two forms of extracellular catalase with different catalytic properties were obtained due to prolonged adaptation to H2O2. Catalase with low affinity for substrate was produced predominantly by the parent culture and variant 3; however, a high substrate affinity of catalase was observed in variant 5. Variant 5 of P. peniceum F-648 displayed a high catalytic activity and operational stability of catalase in the presence of phosphate ions and the concentration of substrate less than 30 mM at pH more than 7.
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PMID:[Resistance of Penicillium piceum F-648 to hydrogen peroxide under short term and prolonged oxidative stress]. 1262 39

The aim of the present study was to investigate the effects of treatment with antioxidant stobadine (ST) on the activities of enzymes related with pentose phosphate pathway and glutathione-dependent metabolism and the other markers of oxidative stress in brain and peripheral organs of diabetic rats, and to compare the effects of ST treatment alone with the effects of treatments with another antioxidant vitamin E and ST plus vitamin E. Rats were made diabetic by the injection of streptozotocin (STZ; 55 mg/kg IP), and, 2 days later, some control and diabetic rats were left untreated or treated with ST (24.7 mg/kg/day, orally), vitamin E (400-500 U/kg/day, orally), or both substances together. In the brain, although 6-phosphogluconate dehydrogenase activity (6-PGD) did not change, glucose-6-phosphate dehydrogenase activity (G-6PD) was markedly increased in diabetic rats compared with controls; only combined treatment with ST and vitamin E produced a partial prevention on this alteration. The aorta G-6PD and 6-PGD of diabetic rats were 52% and 36% of control values, respectively. Neither single treatments with each antioxidant nor their combination altered the G-6PD and 6-PGD in aorta of diabetic rats. Glutathione peroxidase (GSHPx) activity was increased by STZ-diabetes in brain, heart, and kidney. In diabetic brain, vitamin E alone or combination with ST kept GSHPx at normal levels. Diabetes-induced stimulation in GSHPx did not decrease in response to the treatment with vitamin E in heart and kidney, but was greatly prevented by ST alone. The activity of glutathione reductase (GR) was decreased in brain and heart of diabetic rats. The treatment with each antioxidant or with a combination of both agents completely prevented this deficiency and resulted in further activation of GR in diabetic tissues. Glutathione S-transferase (GST) activity did not significantly change in diabetic brain and aorta. GST was stimulated by all treatment protocols in the brain of diabetic rats and was depressed in aorta of control rats. Catalase (CAT) was activated in diabetic heart but depressed in diabetic kidney. Diabetes-induced abnormalities in CAT activity did not respond to vitamin E alone in heart, was moderately ameliorated by the treatment with this vitamin in kidney, and was completely prevented by ST alone in both tissues. Superoxide dismutase (SOD) activity of brain and heart was unchanged by the diabetes but inhibited in diabetic kidney after the treatment ST alone or ST plus vitamin E. The lipid peroxidation (MDA) was increased in diabetic brain and heart. ST or vitamin E alone partly prevented diabetes-induced increase in MDA in brain and heart; however, antioxidant combination achieved a completely amelioration in MDA of these tissues of diabetic rats. Kidney MDA levels were similar in control and untreated diabetic animals. ST and vitamin E treatments, when applied separately or together, significantly reduced kidney MDA in both control and diabetic rats; and the combined effect of antioxidants was greater than that of each alone. These results are consistent with the degenerative role of hyperglycemia on cellular reducing equivalent homeostasis and antioxidant defense, and provide further evidence that pharmacological intervention of different antioxidants may have significant implications in the prevention of the prooxidant feature of diabetes and protects redox status of the cells.
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PMID:Pentose phosphate pathway, glutathione-dependent enzymes and antioxidant defense during oxidative stress in diabetic rodent brain and peripheral organs: effects of stobadine and vitamin E. 1271 33

We examined the combined effects of gamma-radiation (24 degrees C) on spores of Clostridium botulinum-type Eklund strain suspended in different gas-saturated Na-phosphate buffer in absence or presence of protectors or sensitizers. Response surface methodology (RSM) was also used to ascertain the effects of radiation on the recovery of spores using a medium containing various levels of NaCl or Na-thioglycollate. The former (< 0.5%) decreased viable spore counts, but the latter (0.15%) did not. Irradiation inactivation of Eklund spores was most effective in air-saturated buffers compared to N2O and N2 gas. The Na2-EDTA (0.01 M) was the most efficient radioprotector of spores due to its reactivity toward hydroxy radicals, followed by t-butanol (0.1 M) in NO2 or N(2)-saturated buffers, respectively. Catalase (10.0 mg ml(-1)) and DL-cysteine (0.1 mM) sensitized the spores during irradiated N2O or N(2)-saturated buffers, and NaCl (0.01 M) only sensitized spores in N2 environment. Spores frozen at -75 degrees C for 30 days and thawed prior to use were more sensitive to radiation damage compared to freshly prepared spores. Glycerol (15%), in Na-phosphate buffer (pH 7.0, 0.06 M), protected Eklund spores and increased the number of spores from 10(6) to 10(11) colony forming unit (CFU) ml(-1), and enhanced their radiosensitivities. Seven strains of C. botulinum type E were screened for plasmids and strain BL764 had two plasmids (15.8 and 46.8 mDa), BL4028 also had two (4.4 and 13.2 mDa), BL4850 contained only one (4.9 mDa), whereas EQA, BL211, Eklund, and Beluga had none. Gamma-Radiation (10 kGy, absorbed dose) cured the 15.8-mDa plasmid in strain BL764, but its absence yielded no changes in toxigenicity.
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PMID:Combined effects of ionizing-irradiation and different environments on Clostridium botulinum type E spores. 1462 91


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