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

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

Administration of N-hydroxy-2-acetylaminofluorene (90 mumol/kg, iv) to rats results in damage to periportal hepatocytes. The most prominent ultrastructural changes are the appearance of numerous unusual vesicles of about 200 nm diameter and the proliferation of the endoplasmic reticulum to form fingerprint-like structures. In order to characterize these vesicles and to investigate their possible origin, their enzymatic activity was studied by ultrastructural enzyme histochemistry. The vesicles as well as the fingerprint-like structures exhibited glucose-6-phosphatase activity. Continuities between the vesicles and the membranes of both the RER and the SER were frequently seen. The vesicles lacked ATPase, 5'nucleotidase and catalase activity. From these results we conclude that the vesicles may be an unusual proliferation of the endoplasmic reticulum.
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PMID:Genesis of unusual vesicles in rat periportal hepatocytes after administration of N-hydroxy-2-acetylaminofluorene. 614 30

We have studied the effects of adriamycin (doxorubicin HCl) on human red blood cells. The peroxidizing effect of adriamycin on the thiols of red cell constituents resulted in decreased glutathione stability, and oxidation of hemoglobin and membrane protein components 1, 2, and 3, forming large molecular weight complexes. Membrane lipids were also peroxidized. Adriamycin itself did not inhibit the enzymes of the reductions system (glucose-6-phosphate dehydrogenase, 6-phosphogluconic dehydrogenase, glutathione reductase, glutathione peroxidase, catalase, superoxide dismutase) of the red cells. Because adriamycin has the potential of inhibiting ATPase, including both Na-K-dependent ATPase and ouabain insensitive ATPase, at concentrations not inhibitory to other enzymes, the net sodium content increased, and potassium content decreased after incubation of red cells with adriamycin at high concentrations. The experimental results described with adriamycin may serve as a model for the possible mechanism of cardiotoxicity observed in its clinical use, and also explain the potential hemolyzing effect on red cells. There was greater oxidizing effect on glucose-6-phosphate dehydrogenase (G-6-PD) deficient than on normal erythrocytes. It is suggested that adriamycin be used with caution in individuals with G-6-PD deficient red cells.
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PMID:The effects of adriamycin (doxorubicin HCl) on human red blood cells. 625 23

The subcellular localization of the omega-hydroxylase of Saccharomycopsis lipolytica was assessed by the analytical fractionation technique, originally described by de Duve C., Pressman, B.C., Gianetto, R., Wattiaux, R. and Appelmans, F., and hitherto little, if at all, applied to yeasts. Protoplasts were separated in six fractions by differential centrifugation. Some of these fractions were further fractionated by density gradient centrifugation. The distribution of omega-hydroxylase and 15 other constituents chosen as possible markers of its subcellular entities. (1) Mitochondria were characterized by particulate malate dehydrogenase, particulate Antimycin A-insensitive NADH-cytochrome c reductase, oligomycin-sensitive and K+-stimulated ATPase pH 9. (2) Most if not all of the catalase and urate oxidase is peroxisomal. (3) Free ribosomes account for most RNA. (4) Nucleoside diphosphatase is for the first time reported in a yeast and appears to belong to an homogeneous population of small membranes. (5) The soluble compartment contains magnesium pyrophosphatase, alkaline, 5'-nucleotidase and part of the NADH-cytochrome c reductase. Latent arylesterase and ATPase pH 7 have an unspecific distribution. Alkaline phosphodiesterase I has not been detected.
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PMID:Subcellular distribution of enzymes in the yeast saccharomycopsis lipolytica, grown on n-hexadecane, with special reference to the omega-hydroxylase. 626 2

In this report the disturbances in biochemistry of the heart muscle exposed to alcohol are delineated. All elements of cellular substructures are affected. In plasma membranes, (Na+ + K+)-activated ATPase (EC 3.6.1.3) is inhibited. Mitochondrial damage consists in diminished respiratory function and calcium uptake and binding. High-energy phosphates remain intact. Alcohol also affects the malate-aspartate shuttle. Acetaldehyde, a metabolite of ethanol, has a direct effect on myocardial protein synthesis through microsomal inhibition; however, the development of cardiac hypertrophy is not affected. Malfunction of sarcoplasmic reticulum is evidenced by disturbances in calcium binding and uptake. Effects of ethanol on the contractile machinery are deficiencies in the turnover rate of chemical into mechanical energy (diminished Vmax), and in the number of cross-bridges formed (P0). It increases stiffness of series elastic elements. There is diminished fatty acid oxidation with increased esterification. The involvement of CoA synthetase (EC 6.2.1.1), palmityl-carnitine transferase (EC 2.3.1.7), and pyruvate dehydrogenase complex in disturbed fatty acid oxidation is not certain. The role of catalase in myocardial ethanol oxidation was examined. Ethanol activates myocardial catalase-H2O2 complex (EC 1.11.1.6). The biochemical basis of fetal alcohol syndrome is low hepatic alcohol dehydrogenase (EC 1.1.1.1) activity during fetal life.
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PMID:Effect of alcohol on the heart and cardiac metabolism. 628 54

We studied the effect of aclacinomycin on human erythrocyte membrane enzymes. Aclacinomycin inhibited ATPase, including Na-K-dependent ATPase, ouabain insensitive ATPase and Ca-ATPase. However acetylcholinesterase was not inhibited by aclacinomycin. The ATPase activities were not inhibited by aclacinomycin if ascorbate was added to the incubation mixture. However other reducing agents, alpha-tocopherol, superoxide dismutase and catalase had no effect on ATPase activity. Ascorbate may protect membrane proteins and lipids from peroxidate damage.
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PMID:Inhibition of erythrocyte ATPase activity by aclacinomycin and reverse effects of ascorbate on ATPase activity. 631 32

Previous research has shown that heart mitochondria are able to produce reactive species of oxygen such as superoxide radicals, hydrogen peroxide and hydroxyl radicals [10, 11]. When these compounds are formed beyond a certain level they are not completely removed by the enzymatic and metabolic processes which neutralize their toxicity, and as a result they are able to produce structural and functional damages that impair mitochondrial function [5, 10]. In order to study the molecular mechanism/s by which the oxygen radicals may function as mediators of cellular injury a flow of these radicals by chemical, enzymatic or photochemical methods has been generated in vitro in the presence of cellular preparations. For example, the exposure of isolated subcellular particles to the enzymatic flow of oxygen radicals produced by the reaction of xanthine oxidase upon xanthine reduced both calcium uptake velocity and Ca2+-ATPase activity in sarcoplasmic reticulum [7], while it reduced Ca2+-stimulated ATPase activity in myofibrillar preparations [4]. In addition, incubation with the xanthine oxidase reaction produced an impairment of the respiratory functions associated with an increased lipid peroxidation in the isolated mitochondria [5, 10]. These negative effects were augmented in alpha-tocopherol-deficient mitochondria [3], but were opposed by the exogenous addition of superoxide dismutase [10]. This report shows that the superoxide radicals generated by the xanthine oxidase reaction reduced rat heart mitochondrial respiration induced by pyruvate. This negative effect was partially prevented by superoxide dismutase and catalase and by thiol protecting agents. Moreover, the generation of free radicals caused a significant reduction in the rate of (1-14C) -pyruvate decarboxylation, while it did not change the transport of pyruvate into mitochondria.
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PMID:Effect of superoxide generation on rat heart mitochondrial pyruvate utilization. 631 22

Proximal tubules were isolated in highly pure form from rabbit cortices by a mechanical procedure that is known to preserve the structural and metabolic aspects of the tubular cells. Postnuclear supernates prepared from the isolated tubules were subjects to isopycnic centrifugation in linear sucrose gradients. The enzyme activities associated with the plasma membrane (gamma-glutamyl transpeptidase, amino-peptidase M, alkaline phosphatase, Na-K-ATPase, and phosphodiesterase I) exhibited sharp unimodal frequency-density profiles with a median density near 1.16 g/ml, which shifted to a heavier density when treated with digitonin. The lysosomal enzymes, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and cathepsin B, and the peroxisomal enzyme catalase exhibited particle-associated activity near a density of 1.22 g/ml. Disruption of these particles by freezing and thawing resulted in these activities appearing in the rho = 1.10 g/ml region of the gradient where the soluble cytosolic enzyme, phosphoglucomutase, exhibited activity. Cytochrome oxidase activity typical of mitochondria gave a sharp unimodal profile at rho = 1.18 g/ml. Microsomal glucose-6-phosphatase and NADPH: cytochrome c reductase activities gave median densities near 1.16 g/ml, which did not change after incubation with digitonin. Galactosyl transferase activity gave a skewed profile at rho = 1.16 g/ml and showed a slight shift to heavier density after digitonin. This study of the enzymatic activities and density gradient distribution of the components of the proximal tubule cells provides the methodology for the further study of the cellular processing of endogenous and exogenous substances by this vital cell type.
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PMID:Analytical cell fractionation of isolated rabbit renal proximal tubules. 730 Jan 16

The Na(+)-K+ ATPase activity and SH group content were decreased whereas malondialdehyde (MDA) content was increased upon treating the porcine cardiac sarcolemma with xanthine plus xanthine oxidase, which is known to generate superoxide and other oxyradicals. Superoxide dismutase either alone or in combination with catalase and mannitol fully prevented changes in SH group content but the xanthine plus xanthine oxidase-induced depression in Na(+)-K+ ATPase activity as well as increase in MDA content were prevented partially. The Lineweaver-Burk plot analysis of the data for Na(+)-K+ ATPase activity in the presence of different concentrations of MgATP or Na+ revealed that the xanthine plus xanthine oxidase-induced depression in the enzyme activity was associated with a decrease in Vmax and an increase in Km for MgATP; however, Ka value for Na+ was decreased. Treatment of sarcolemma with H2O2 plus Fe2+, an hydroxyl and other radical generating system, increased MDA content but decreased both Na(+)-K+ ATPase activity and SH group content; mannitol alone or in combination with catalase prevented changes in SH group content fully but the depression in Na(+)-K+ ATPase activity and increase in MDA content were prevented partially. The depression in the enzyme activity by H2O2 plus Fe2+ was associated with a decrease in Vmax and an increase in Km for MgATP. These results indicate that the depressant effect of xanthine plus xanthine oxidase on sarcolemmal Na(+)-K+ ATPase may be due to the formation of superoxide, hydroxyl and other radicals. Furthermore, the oxyradical-induced depression in Na(+)-K+ ATPase may be due to the formation of superoxide, hydroxyl and other radicals.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Inhibition of cardiac sarcolemma Na(+)-K+ ATPase by oxyradical generating systems. 749 43

A cyanobacterial sulfur-regulated gene (cysR), which encodes a protein with similarity to the Crp family of prokaryotic regulatory proteins, has recently been isolated and characterized. Polyacrylamide gel electrophoresis of periplasmic protein extracts reveals that a cysR mutant fails to synthesize a 36-kDa polypeptide that is normally induced in wild-type cells that have been grown under sulfur-deficient conditions. The amino-terminal sequence of this protein was obtained, and a synthetic oligonucleotide was used to isolated a clone containing a 1.9-kb NruI-KpnI fragment from a Synechococcus sp. strain PCC 7942 genomic library. RNA blot analysis indicates that this fragment encodes a transcript that is detectable in wild-type but not cysR mutant cells that have been starved for sulfur. DNA blot analysis revealed that the 1.9-kb NruI-KpnI fragment is contained within the Ba4 BamHI fragment of the endogenous 50-kb plasmid pANL. RNA blot studies indicate that the accumulation of a large number of pANL transcripts is regulated by sulfur levels and CysR. DNA sequence analysis confirmed that the gene encoding the sulfur-regulated 36-kDa periplasmic protein is encoded on the Ba4 fragment of pANL. The sequence of the 36-kDa protein displays sequence similarity to the enzyme catalase, and two downstream proteins exhibit 25 and 62% identity to a subunit of a P-type ATPase complex involved in Mg2+ transport and a chromate resistance determinant, respectively. Surprisingly, a strain in which the putative chromate resistance gene was interrupted by a drug resistance marker exhibited increased resistance to chromate when grown in media containing low sulfate concentrations. The possible role of this protein in the acclimation of cyanobacteria to conditions of low sulfur availability is discussed.
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PMID:Genes encoded on a cyanobacterial plasmid are transcriptionally regulated by sulfur availability and CysR. 753 34

We have evaluated the effect of lipopolysaccharides (LPS), endotoxins from gram negative bacteria, on sodium-coupled amino acid and phosphate transport by alveolar epithelial type II cells and on their alteration induced by oxidants. Alveolar type II cells were obtained by enzymatic digestion of rat lung and grown for 24 h prior to incubation with LPS and then exposed or not exposed to H2O2 (2.5 mM; 20 min). LPS (10 micrograms/ml, 24 h) induced a significant increase in the Na-dependent component of alanine and phosphate uptake while they decreased Na,K-ATPase activity measured by ouabain-sensitive 86Rb influx. We showed that this stimulatory effect i) was independent from macrophage products since it was not mimicked either by supernatant of LPS-treated alveolar macrophages or by pretreatment with tumor necrosis factor and/or interleukin 1 and ii) was dependent on protein synthesis since it was abolished by protein synthesis inhibitors cycloheximide and actinomycin D. Moreover, LPS blunted H2O2-induced decrease of Na-dependent alanine and phosphate uptake. This protective effect of LPS against H2O2 injury i) was independent of macrophage products, ii) was abolished by cycloheximide, and iii) was not associated with either changes in extracellular H2O2 clearance or catalase and glutathione peroxidase activities. We conclude that, in alveolar type II cells, LPS stimulate sodium-coupled transport by a process involving protein synthesis and partially prevent H2O2-induced decrease of Na-coupled transport without discernible change in antioxidant activities.
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PMID:Lipopolysaccharides stimulate Na-dependent transport in alveolar cells and protect against oxidant injury. 770 77


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