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

Rat liver catalase mRNA was translated in a rabbit reticulocyte lysates and wheat germ cell-free system in the presence or absence of hemin and/or a translational inhibitor prepared from reticulocytes, liver cells, and wheat germs. Failure to add hemin to the lysates, or the addition of a hemin-regulated translational inhibitor (HRI) to the hemin-supplemented lysates caused a repressed translation. A preparation of inhibitor from rat liver showed activity similar to that of HRI for this translating system. The translation repression by rat liver inhibitor was reversed by eIF-2 (initiation factor) or GTP, but ATP enhanced the repression. The translation of catalase mRNA in the wheat germ system was not affected by the addition of hemin. An inhibitor prepared from wheat germ extracts, as well as the rat liver inhibitor, markedly decreased the rate of translation. eIF-2, GTP, and ATP behaved in the manner described above. Catalase synthesis in a cell-free system derived from rat liver (using endogenous mRNA) was not influenced by either hemin or the inhibitor. The possibilities are discussed that the synthesis of catalase in liver cells is controlled by a translational inhibitor at the level of chain initiation, and that the formation of the inhibitor from its inactive proinhibitor is regulated by the amount of heme.
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PMID:Studies on rat liver catalase. X. Effect of hemin and an inhibitor on the translation of catalase messenger RNA1. 42 38

In photosynthetically competent chloroplasts from spinach the quantum requirements for oxygen evolution during CO2 reduction were higher, by a factor often close to 1.5, than for oxygen evolution during reduction of phosphoglycerate. Mass spectrometer experiments performed under rate-limiting light indicated that an oxygen-reducing photoreaction was responsible for the consumption of extra quanta during carbon dioxide assimilation. Uptake of 18O2 during reduction of CO2 was considerably higher than could be accounted for by oxygen consumption during glycolate formation and by the Mehler reaction of broken chloroplasts which were present in the preparations of intact chloroplasts. The oxygen reducing reaction occurring during CO2 assimilation resulted in the formation of H2O2. This was indicated by a large stimulation of CO2 reduction by catalase, but not of phosphoglycerate reduction. Catalase could be replaced as a stimulant of photosynthesis by dithiothreitol or ascorbate, compounds known to react with superoxide radicals. There was no effect of dithiothreitol and ascorbate on phosphoglycerate reduction. A main effect of superoxide radicals and/or H2O2 was shown to be at the level of phosphoglycerate formation. Evidence for electron transport of oxygen was also obtained from 14CO2 experiments. The oxidation of dihydroxyacetonephosphate during a dark period or after addition of carbonyl cyanide p-trifluoromethoxyphenyl-hydrazone in the light was studied. The results indicated a link between the chloroplast pyridine nucleotide system and oxygen. Oxygen reduction during photosynthesis under conditions where light is rate limiting is seen as important in supplying the ATP which is needed for CO2 reduction but is not provided during electron transport to NADP. A mechanism is discussed which would permit proper distribution of electrons between CO2 and oxygen during photosynthesis.
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PMID:Reduction of oxygen by the electron transport chain of chloroplasts during assimilation of carbon dioxide. 119 61

Rifamycins are antibacterial antibiotics which are especially useful for the treatment of tuberculosis. Reactive oxygen intermediates are produced in the presence of rifamycin SV and metals such as copper or manganese. Experiments were carried out to evaluate the interaction of rifamycin SV with rat liver microsomes to catalyze the production of reactive oxygen species. At a concentration of 1 mM, rifamycin SV increased microsomal production of superoxide with NADPH as cofactor 3-fold, and with NADH as reductant by more than 5-fold. Rifamycin SV increased rates of H2O2 production by the microsomes twofold with NADPH, and 4- to 8-fold with NADH. In the presence of various iron complexes, microsomes generated hydroxyl radical-like (.OH) species. Rifamycin SV had no effect on NADPH-dependent microsomal .OH production, irrespective of the iron chelate. A striking stimulation of .OH production was found with NADH as the reductant, ranging from 2- to 4-fold with catalyst such as ferric-EDTA and ferric-DTPA to more than 10-fold with ferric-ATP, -citrate, or -histidine. Catalase and competitive .OH scavengers lowered rates of .OH production (chemical scavenger oxidation) and prevented the stimulation by rifamycin. Superoxide dismutase had no effect on the NADH-dependent rifamycin stimulation of .OH production with ferric-EDTA or -DTPA, but was inhibitory with the other ferric complexes. In contrast to the stimulatory effects on production of O2-., H2O2, and .OH, rifamycin SV was a potent inhibitor of microsomal lipid peroxidation. These results show that rifamycin SV stimulates microsomal production of reactive oxygen intermediates, and in contrast to results with other redox cycling agents, is especially effective with NADH as the microsomal reductant. These interactions may contribute to the hepatotoxicity associated with use of rifamycin, and, since alcohol metabolism increases NADH availability, play a role in the elevated toxic actions of rifamycin plus alcohol.
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PMID:Stimulation of microsomal production of reactive oxygen intermediates by rifamycin SV: effect of ferric complexes and comparisons between NADPH and NADH. 132 62

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

The respective roles of H2O2 and .OH radicals was assessed from the protective effects of catalase and the iron chelator o-phenanthroline on 1) the inhibition of protein synthesis, and 2) DNA damage and the related events (activation of the DNA repairing enzyme poly(ADP)ribose polymerase with the associated depletion of NAD and ATP stores) in cultured endothelial cells exposed to the enzyme reaction hypoxanthine-xanthine oxidase (HX-XO) or pure H2O2. Catalase added in the extracellular phase completely prevented all of these oxidant-induced changes. O-phenanthroline afforded a complete protective effect against DNA strand breakage and the associated activation of the enzyme poly(ADP)ribose polymerase. By contrast, iron chelation was only partially effective in maintaining the cellular NAD and ATP contents, as well as the protein synthetic activity. In addition, the ATP depletion following oxidant injury was much more profound than NAD depletion. These results indicate that: 1) .OH radical was most likely the ultimate O2 species responsible for DNA damage and activation of poly(ADP)ribose polymerase; 2) both H2O2 and .OH radicals were involved in the other cytotoxic effects (inhibition of protein synthesis and reduction of NAD and ATP stores); and 3) NAD and ATP depletion did not result solely from activation of poly(ADP)ribose polymerase, but other mechanisms are likely to be involved. These observations are also compatible with the existence of a compartmentalized intracellular iron pool.
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PMID:Differential protective effects of O-phenanthroline and catalase on H2O2-induced DNA damage and inhibition of protein synthesis in endothelial cells. 166 Apr 79

When isolated rat heart mitochondria are subject to xanthine/xanthine oxidase generated free radicals, nmol quantities of ADP are phosphorylated to ATP. This effect is proportional to xanthine oxidase concentration, and is relatively independent of ADP concentration. Exogenous superoxide dismutase partially suppresses the phosphorylation. Micromolar concentrations of iron salts completely eliminate the phosphorylation. Catalase has no effect. The likely electron source, then, is superoxide radicals. The reduced minus oxidised spectra of superoxide-bombarded mitochondria show that superoxide enters the electron transport chain by reducing cytochrome c and complex IV. Mitochondria retain their ability to phosphorylate ADP in more traditional ways under the experimental conditions described. Superoxide under physiological conditions in vivo may be a source of electrons for the oxidative phosphorylation of ADP.
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PMID:Superoxide radical as electron donor for oxidative phosphorylation of ADP. 216 11

The Fischer rat is known for its susceptibility to develop liver necrosis when challenged with paraquat (Smith et al., J. Pharmacol. Exp. Ther. 235: 172-177, 1985). We postulated that other organs, specifically the lung, may also be more susceptible to injury and examined whether lungs from Fischer (F) rats were injured more easily when challenged with active oxygen species than Sprague-Dawley (SD) rat lungs. We aimed to investigate whether increased susceptibility to oxidant injury was related to differences in lung antioxidant defenses. Perfused lungs from both rat strains were challenged by addition of H2O2 to the perfusate or by short-term hyperoxic ventilation. To assess nonoxidant modes of lung injury, we examined lung responses after exposure to protamine sulfate or neutrophil elastase. Intravascular H2O2 or 3 h in vitro hyperoxia caused lung edema in F but not SD rats, and elastase injured F rat lungs more than the lungs from SD rats. Protamine, however, injured the lungs from both strains to a similar degree. Catalase, but not superoxide dismutase or allopurinol, protected F rat lungs against edema, resulting from 3 h in vitro hyperoxia. The lung homogenate levels for reduced glutathione or conjugated dienes and the activities of lung tissue catalase, glutathione peroxidase, and cytochrome P-450 were not different between the two strains. Lung tissue ATP levels, however, were lower in F than in SD rats. Although the F rat strain appears to have an altered oxidant-antioxidant defense balance, the exact cause of the greater susceptibility to oxidant stress of the F rat strain remains elusive.
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PMID:Lung injury in Fischer but not Sprague-Dawley rats after short-term hyperoxia. 226 Jun 76

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

The activity of acetyl-CoA hydrolase (dimeric form) purified from the supernatant fraction of rat liver was shown to have a half-life (t1/2) of 3 min at 0 degree C, but to stable at 37 degrees C (t1/2 = 34 h) [Isohashi, F., Nakanishi, Y. & Sakamoto, Y. (1983) Biochemistry 22, 584-590]. Incubation of the purified enzyme with L-ascorbic acid (AsA) at 37 degrees C resulted in inactivation of the enzyme (t1/2 = 90 min at 2 mM AsA). The extent of inactivation was greatly enhanced by addition of transition metal ions (Cu2+, Fe2+, and Fe3+). Thiol reducing agents, such as reduced glutathione and DL-dithiothreitol, protected the hydrolase from inactivation by AsA. However, these materials did not restore the catalytic activity of the enzyme inactivated by AsA. When AsA solution containing Cu2+ was preincubated under aerobic conditions at 37 degrees C for various times in the absence of enzyme, and then aliquots were incubated with the enzyme solution for 20 min, remaining activity was found to decrease with increase in the preincubation time, reaching a minimum at 60 min. However, further preincubation reduced the potential for inactivation. Catalase, a hydrogen peroxide (H2O2) scavenger, almost completely prevented inactivation of the enzyme by AsA plus Cu2+. Superoxide dismutase and tiron, which are both superoxide (O2-) scavengers, also prevented inactivation of the enzyme. A high concentration of mannitol, a hydroxyl radical (OH) scavenger, partially protected the enzyme from inactivation. These results suggest that inactivation of the enzyme by AsA in the presence of Cu2+ was due to the effect of active oxygen species (H2O2, O2-, OH) that are known to be autoxidation products of AsA. Valeryl-CoA, a competitive inhibitor of acetyl-CoA hydrolase, greatly protected the enzyme from inactivation by AsA plus Cu2+, but ATP and ADP, which are both effectors of this enzyme, had only slight protective effects. These results suggest that inactivation of this enzyme by addition of AsA plus Cu2+ was mainly due to attack on its active site.
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PMID:Oxidative inactivation of an extramitochondrial acetyl-CoA hydrolase by autoxidation of L-ascorbic acid. 286 35

The direct in vitro effects of alloxan on the Ca2+ handling by microsomal membranes isolated from dog mesenteric arteries were investigated. Preincubation of the vascular muscle microsomal membranes with alloxan showed a suppressive effect on both binding of Ca2+ (in the absence of ATP) and ATP-driven Ca2+ transport. Such an inhibition was time dependent, dose dependent, and temperature dependent. ATP-driven Ca2+ transport was much more susceptible to the inhibitory action of alloxan than Ca2+ binding under all experimental conditions examined. Alloxan inhibited ATP-driven Ca2+ transport at a comparable level over the entire period of Ca2+ uptake, but had no significant effect on the efflux of Ca2+ from preloaded microsomal membranes. This suggests that alloxan exerts its inhibitory effect on the ATP-driven Ca2+ transport via its action on the Ca-pump protein rather than the membrane permeability to Ca2+. Catalase and mannitol but not superoxide dismutase partially protected against such as inhibition by alloxan. The possible involvement of H2O2 mediating the inhibitory action of alloxan was further supported by the finding of a similar in vitro inhibitory effect of H2O2 on the ATP-driven Ca2+ transport by the vascular smooth muscle microsomes.
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PMID:Mechanism of inhibition by alloxan of ATP-driven calcium transport by vascular smooth muscle microsomes. 297 55


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