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

In the presence of intact Ehrlich ascite carcinoma cells and the supernatant obtained by preincubation and subsequent precipitation of cells, egg phosphatidylcholine is oxidized in liposomes to form malonic dialdehyde (MDA). Catalase and carbon dioxide markedly reduce, whereas sodium azide increases MDA accumulation during liposome incubation with the cells. EDTA, diethylthiocarbonate and alpha-tocopherol effectively inhibit, whereas ascorbate and cysteine strongly activate MDA synthesis in both cases. Superoxide dismutase has no appreciable effect on these processes. It is concluded that metal-containing catalysts and the H2O2 released by intact cells into the incubation medium induce lipid peroxidation in liposomes.
 ...
PMID:[Mechanism of formation of malonic dialdehyde during liposome interaction with cells]. 320 6

The mechanism of cytogenetic genotoxicity (clastogenicity, induction, cell cycle delay) of 10(-3) M glutathione in V79-E cells, as described by Thust and Bach (1985), was studied in detail by using different treatment conditions. It was found that 1-cystine is the essential cofactor in the incubation system. Catalase, but not superoxide dismutase, abolished the genotoxic effect, and the iron chelator desferoxamine, as well as the hydroxyl radical scavenger mannitol, diminished the activity. It is suggested that glutathione, in combination with V79-E cells and cystine, forms a hydrogen peroxide-generating system which provokes the adverse effects. Glutathione as well as 1-cysteine and 2-mercaptopropionylglycine, which were checked for comparison, show a "paradoxic genotoxicity," i.e., at 10(-2) M the effects return almost to the level of controls. Concentration dependence and other criteria of cytogenetic genotoxicity observed with glutathione show obvious similarities to those of other oxidatively acting agents and reveal striking differences to the cytogenetic effects of "typical" genotoxins.
 ...
PMID:The mechanism of cytogenetic genotoxicity of exogenous glutathione in V-79 cells in vitro--implication of hydrogen peroxide and general traits of oxidative chromosome damage. 323 33

1. Glutathione (GSH) and cysteine, added to the constituted incubation medium, rapidly disappeared from the medium in the presence of bovine serum albumin (BSA). The major portions of added GSH and cysteine were oxidized. Only a fraction was recovered as cysteine-GSH mixed disulfide in case of GSH. About 15-30% cysteine or GSH were not recovered in the media. 2. The rate of GSH oxidation was linear with time, however, GSH disappearance was not linear with GSH concentrations. 3. Oxidation of GSH to GSSG in the albumin supplemented media was greater under O2 atmosphere, but was significantly decreased under N2 atmosphere. 4. Catalase, a peroxy radical scavenger, but not dimethyl pyroline N-oxide (DMPO), N-tertbutyl-2(-2 sulfophenyl)-nitrone (NTBSPN), mannitol or superoxide dismutase (SOD), decreased BSA mediated GSH oxidation. 5. GSH oxidation was abolished when mono- or divalent metal ions were absent in the BSA supplemented media. 6. Alkaline pH favored and acidic pH inhibited GSH oxidation. GSH oxidation was maximum above pH 7.4. GSH oxidation was minimal in the media containing boiled BSA. 7. A reaction mechanism involving the mixed GSH-BSA disulfide formation, followed by the reduction of these disulfides by GSH and subsequent release of GSSG is proposed.
 ...
PMID:Glutathione status in constituted physiological fluids containing albumin. 342 75

Dithranol (0.01-1 micrograms/ml), but not the auto-oxidized form, caused a dose-related enhancement of the generation of reactive oxidants by leukoattractant-activated polymorphonuclear leukocytes (PMNL) in vitro. At the same concentrations dithranol inhibited both PMNL migration to leukoattractants and mitogen-stimulated mononuclear leukocyte (MNL) proliferation. Catalase (50-100 units/ml) protected both PMNL migration and MNL proliferation from dithranol whilst ascorbate and cysteine (1 mM), which maintain dithranol in the biologically active reduced state, potentiated the inhibition. To establish the molecular mechanism of the pro-oxidative activity of dithranol its effects on cytosolic protein kinase C (PKC) activity were investigated. Dithranol caused a dose-related activation of PKC by apparent substitution for 1,2-diolein. These results demonstrate that dithranol, but not its auto-oxidation products, activates PKC which in turn initiates the generation of reactive oxidants by PMNL. Since reactive oxidants are immunosuppressive the therapeutic mechanisms of dithranol may be related to pro-oxidative interactions of this agent with skin phagocytes.
 ...
PMID:Dithranol mediates pro-oxidative inhibition of polymorphonuclear leukocyte migration and lymphocyte proliferation. 367 90

Autooxidation of reduced glutathione in 50 mM buffer at pH 7.9 is indetectably slow in the presence of 1 mM DETAPAC, EDTA, TET, or tripyridine, but passing buffer through Chelex resin was insufficient to remove traces of catalytically active metals. Production of hydrogen peroxide during glutathione autooxidation was catalyzed by traces of Fe+2 or Cu+2, and to a much lesser extent by Cu+1 and Ni+2, but not to a detectable extent by Na+1, K+1, Fe+3, Al+3, Cd+2, Zn+2, Ca+2, Mg+2, Mn+2, or Hg+2. Cysteine was a much better precursor for hydrogen peroxide production than were cysteine sulfinic or sulfonic acids. The chelators EGTA, NTA, bipyridine, dimethyl glyoxime, salicylate, and Desferal were ineffective at preventing autooxidation. EDDA and 8-hydroxyquinoline were partially effective. Catalase could completely prevent the accumulation of detectable H2O2, but superoxide dismutase was only slightly inhibitory. Hydroxyl radical and singlet oxygen quenching agents (mannitol and histidine) stimulated. A mechanism for the production of H2O2 during trace metal catalyzed oxidation of glutathione is proposed, involving glutathione-complexed metal and dissolved oxygen. Although a radical intermediate can not be ruled out, no radical initiated chain reaction is necessary.
 ...
PMID:Generation of hydrogen peroxide by incidental metal ion-catalyzed autooxidation of glutathione. 376 Aug 59

Detailed quantitative studies on the mutagenicity of methylglyoxal showed that its contribution to the total mutagenicity of instant coffee on S. typhimurium TA100 was minor although we reported previously (Kasai et al., 1982) that its contribution to the mutagenicity of freshly brewed coffee was about 50%. Cysteine suppressed the mutagenicity of methylglyoxal and of methylglyoxal when added to instant coffee, but did not affect the mutagenicity of coffee itself. Catalase suppressed most of the mutagenicity of coffee, but not that of methylglyoxal or of methylglyoxal added to coffee.
 ...
PMID:Characteristics of major mutagenicity of instant coffee. 388 16

The catalase activity of cultured rat hepatocytes was inhibited by 90% pretreatment with 20 mM aminotriazole without effect on the activities of glutathione peroxidase or glutathione reductase, or on the viability of the cells over the subsequent 24 h. Glutathione reductase was inhibited by 85% by pretreatment with 300 microM 1,3-bis(2-chloroethyl)-1-nitrosourea (BCNU) without effect on glutathione peroxidase, catalase, or on viability. Both pretreatments sensitized the hepatocytes to the cytotoxicity of H2O2 generated either by glucose oxidase (0.05-0.5 units/ml) or by the autoxidation of the one-electron-reduced state of menadione (50-250 microM). Aminotriazole pretreatment had no effect on the GSH content of the hepatocytes. BCNU reduced GSH levels by 50%. Depletion of GSH levels to less than 20% of control by treatment with diethyl maleate, however, did not sensitize the cells to either glucose oxidase or menadione, indicating that the effect of BCNU is related to inhibition of the GSH-GSSG redox cycle rather than to the depletion of GSH. With glucose oxidase, most of the cell killing in hepatocytes pretreated with either aminotriazole or BCNU occurred between 1 and 3 h. The antioxidant diphenylphenylenediamine (DPPD) had no effect on viability at 3 h. Catalase added to the culture medium 1 h after the addition of glucose oxidase prevented the cell killing measured at 3 h. The sulfhydryl reagents dithiothreitol (200 microM), N-acetyl-L-cysteine (4 mM), and alpha-mercaptopropionyl-L-glycine (2.5 mM) prevented the cell killing with exogenous H2O2 in hepatocytes sensitized by the inhibition of catalase or glutathione reductase. With menadione, there was no killing of nonpretreated hepatocytes at 1 h, and DPPD did not prevent the cell death after 3 h. Aminotriazole pretreatment enhanced the cell killing at 3 h but not at 1 h, and DPPD was not protective. Catalase added to the medium at 1 h inhibited the cell death measured at 3 h. In contrast, menadione killed hepatocytes pretreated with BCNU within 1 h. DPPD prevented cell death at 1 h, and there was evidence of lipid peroxidation in the accumulation of malondialdehyde in the culture medium. Catalase added with menadione did not prevent the cell killing at 1 h but did prevent it at 3 h. These data indicate that catalase and the GSH-GSSG cycle are active in the defense of hepatocytes against the toxicity of H2O2.(ABSTRACT TRUNCATED AT 400 WORDS)
 ...
PMID:Endogenous defenses against the cytotoxicity of hydrogen peroxide in cultured rat hepatocytes. 396 66

Some of the factors influencing the oxygen uptake and peroxide formation for cysteamine (MEA) and other thiols in serum-supplemented modified McCoy's 5A, a well-known medium used to cultivate a variety of cells in vitro, have been studied. The oxidation of MEA and cysteine in modified McCoy's 5A has been compared with that in Ham's F-12, MEM, and phosphate-buffered saline. All of the growth media were supplemented with 10% calf serum and 5% fetal calf serum. The rate of oxygen uptake for all of the studied thiols was greatest in McCoy's 5A. The data indicate that this medium may contain more copper than the other preparations. MEA and cysteine were found to be more effective at 0.4 mM at producing peroxide than dithiothreitol (DTT). N-acetylcysteine was the least reactive. The ability to produce peroxide is dependent upon the temperature, the concentration of thiol, the presence of copper ions, and pH of the medium. MEA and other thiol oxidation is inhibited by the copper chelator diethyldithiocarbamate. Catalase also reduces the oxygen uptake for all thiols. This inhibition involves the recycling of peroxide to oxygen. Superoxide dismutase (SOD) was found to stimulate the oxygen uptake in the case of MEA and cysteine, but had little or no effect with DTT and glutathione. The combined presence of SOD and catalase resulted in less inhibition of oxygen uptake than that obtained by catalase alone. Alkaline pH was found to enhance the oxidation of cysteine and MEA. An important observation was the inhibition of MEA oxidation at 0 degrees C and the stimulation at 42 degrees C. The results indicate that many problems may arise when thiols are added to various media. A major consideration is concerned with the production of peroxide, superoxide, and reduced trace metal intermediates. The presence of these intermediates may result in the production of hydroxyl radical intermediates as well as the eventual oxygen depletion from the medium. Oxygen depletion may alter the results of radiation sterilization and carcinogen activation. Radical production will cause cell damage that is temperature dependent. Therefore, careful consideration must be given to changes in oxygen tension when thiols are added to cells growing in complicated growth medium to protect against either chemical or radiation damage.
 ...
PMID:Factors influencing the oxidation of cysteamine and other thiols: implications for hyperthermic sensitization and radiation protection. 609 88

The medium of cultured melanoma cells was studied for tyrosine hydroxylation and dopa-oxidizing activity. The supernatant obtained after centrifugation at 100 000 g for 2 hours was treated with ammonium sulphate, and the precipitate obtained between 35 and 50% saturation was used. Dopa was determined as the product of tyrosine hydroxylation and 5-S-cysteinyldopa as the product of dopa oxidase activity. Determinations were performed with HPLC and electrochemical detection. Our preparation of culture medium of cells showed the following. 1) No hydroxylation of tyrosine in the absence of co-factor. 2) Hydroxylation of L-tyrosine in the presence of dopamine. No hydroxylation with boiled medium. Minimal effect of catalase on hydroxylation. 3) Hydroxylation of tyrosine in the presence of ascorbic acid. Hydroxylation was catalyzed also with boiled medium. Catalase strikingly diminished hydroxylation. 4) Oxidation of L-dopa to dopaquinone determined as its main reaction product with cysteine, 5-S-cysteinyl-dopa. There was negligible oxidation with boiled medium. 5) With dopamine as co-factor the catalysis of tyrosine hydroxylation was stereospecific for L-tyrosine. Dopa oxidase activity was also stereospecific for L-dopa.
 ...
PMID:Tyrosinase activity in the medium of human melanoma cell cultures. 619 32

Cytotoxicity of catechols has been ascribed to their binding with proteins through sulfhydryl groups. The possibility that iron-protein complexes catalyse this type of covalent binding was studied with a model system. Reaction of dopa and cysteine catalysed by iron-EDTA complexes at physiological pH resulted in the formation of not only cystine but also conjugation products, cysteinyldopas among which 5-S-cysteinyldopa was the major product. The reaction required iron ion, EDTA, and molecular oxygen. Fe3+ and Fe2+ were equally effective, while other transition metal ions examined had no effect on the formation of cysteinyldopas. Catalase, superoxide dismutase, and scavengers of hydroxyl radical inhibited to some extents the formation of 5-S-cysteinyldopa. Addition of both catalase and superoxide dismutase resulted in approximately 60% inhibition. These results indicated that the iron-EDTA-catalysed conjugation of dopa with cysteine was mainly mediated by hydroxyl radical.
 ...
PMID:Oxygen-dependent conjugation of dopa with cysteine catalysed by iron-EDTA complex. 643 77


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