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)

Five enzymes were measured in 50 liver specimens (18 normal liver, 20 Reye liver, 12 diverse liver disorders other than Reye syndrome). The enzymes were: glutamic dehydrogenase (E.C. 1.4.1.3), monoamine oxidase (E.C. 1.4.3.4), lactate dehydrogenase (E.C. 1.1.1.27), D-glucose-6-phosphate dehydrogenase (E.C. 1.1.1.49), catalase (E.C. 1.11.1.6). The Reye syndrome group showed significant decreases in glutamic dehydrogenase (56%) and monoamine oxidase (70%) compared to normal control tissue and these changes were not characteristic of the non-Reye liver disorder group as a whole. Neither catalase nor lactate dehydrogenase appeared to be altered significantly in the Reye or in the abnormal control group compared with normal controls. Thus, only the prominent decreases in the mitochondrial enzyme activities appeared to be highly characteristic of Reye syndrome. Paradoxically, the means of the five hepatic enzymes and the admission levels of two serum enzymes indicative of liver damage (alanine and aspartate aminotransferase) were remarkably similar for both survivors and nonsurvivors of Reye syndrome.
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PMID:Quantitative evaluation of the extent of hepatic enzyme changes in Reye syndrome compared with normal liver or with non-Reye liver disorders: objective criteria for animal models. 396 10

The subcellular localization of alanine-glyoxylate aminotransferase (EC 2.6.1.44 L-Alanine: glyoxylate aminotransferase) of adult human liver was examined by sucrose density gradient centrifugation. The enzyme sedimented at the same density as catalase, indicating that it was localized in the peroxisomes. Alanine-glyoxylate aminotransferase activity in the liver of patients with cirrhosis was about 65% of that of normal liver or 71% of that from patients with chronic hepatitis, but its activity in the serum of patients with cirrhosis was higher than that from patients with chronic hepatitis. Patterns of activity of alanine-glyoxylate aminotransferase in liver and serum differed from those of aspartate-2-oxoglutarate aminotransferase and ornithine carbamoyltransferase that have a different intracellular location. Serum immunoreactive alanine-glyoxylate aminotransferase (Im-AGT) was measured by enzyme-linked immunoadsorbent assay (ELISA). The Im-AGT levels (mean +/- SEM) in acute (80 +/- 13 micrograms/L) and chronic (72 +/- 4 micrograms/L) hepatitis were higher than those of normal controls (44 +/- 1 micrograms/L). However, the difference between acute and chronic hepatitis was not statistically significant. The level in liver cirrhosis (54 +/- 3 micrograms/L) was lower than those of the hepatitides but higher than that of normal controls. The apparent half-life of serum Im-AGT of patients who underwent liver lobectomy by a microwave tissue coagulation method was approximately 3-4 days.
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PMID:Peroxisome localized human hepatic alanine-glyoxylate aminotransferase and its application to clinical diagnosis. 405 44

Fourteen strains of catalase-positive, Gram-positive and coagulase-negative cocci that were sensitive to 20 micrograms/ml of furazolidone were isolated from goats and sheep. Two of the strains had glycerol with glucose teichoic acids whilst another possessed glycerol, glucose, glucosamine and acetylglucosamine teichoic acids. Six strains had peptidoglycan type L-Lys-Ala-Gly4 peculiar to Staphylococcus sciuri and Staph. lentus but other phenotypic characters were different from those of Staph. sciuri and Staph. lentus. The guanine plus cytosine (G + C) content of the DNA determined for three of the strains examined ranged from 32.9-34.6 mol %. The coagulase-positive staphylococcal strain of caprine origin examined had glycerol and glucosamine teichoic acids in addition to peptidoglycan type L-Lys-Gly5-6. The characteristics of the strains of staphylococci described herein are different from those already described in the literature.
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PMID:Characteristics of some unclassifiable strains of staphylococci isolated from goats and sheep. 405 38

L-[1-11C]Lactic acid was prepared enzymatically from [1-11C]pyruvic acid by way of DL-[1-11C]alanine, using remote, semiautomated procedures. The DL isomers of alanine were prepared by a modification of the Bucherer-Strecker reaction from no-carrier-added (NCA) hydrogen [11C]cyanide. The enantiomer mixture was transformed to [1-11C]pyruvic acid by successive elution through columns of (a) immobilized D-amino acid oxidase (D-AAO)/catalase and (b) immobilized L-alanine dehydrogenase (L-AID) or L-amino acid oxidase (L-AAO/catalase). [1-11C]-Pyruvic acid was subsequently converted to L-[1-11C]lactic acid by passage through a L-lactic dehydrogenase (L-LDH) column. L-[1-11C]Alanine and [1-11C]-pyruvic acid were separated chromatographically by way of a cation-exchange column (AG50W-X2, H+ form). Typically the synthesis time was 35-40 min after cyclotron production of hydrogen [11C]cyanide (400 mCi), with radiochemical yields of 25 mCi (25%) for L-[1-11C]lactic acid, 35 mCi (29%) for [1-11C]pyruvic acid, and 20 mCi (20%) for L-[1-11C]alanine. The use of immobilized enzymes eliminates the possibility of protein contamination and assures the production of sterile, pyrogen-free products, allowing for rapid and effective regio- and stereo-specific transformations.
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PMID:Enzymatic synthesis of [1-11C]pyruvic acid, L-[1-11C]lactic acid and L-[1-11C]alanine via DL-[1-11C]alanine. 661 89

Cu++ was uniquely capable of catalyzing the peroxidation of rat erythrocyte membrane lipid in the presence of 10 mM H2O2, whereas several other transition metal ions were without significant effect. In contrast, peroxidation of soybean phospholipid liposomes could be catalyzed with decreasing efficiency by Co++, Cu++, Pb++, or Cr+++ also in the presence of H2O2. The effect of imidazole on Cu++- catalyzed lipid peroxidation was stimulatory in liposomes and inhibitory in membrane preparations, whereas EDTA, histidine, citrate and alanine inhibited peroxidation in both systems. EDTA could stop the peroxidation after initiation, but catalase could not, indicating that Cu++ alone was necessary for the propagation of the chain reaction. Competitive inhibition studies with various scavengers of hydroxyl radicals or singlet oxygen and the absence of significant reaction enhancement by D2O indicated that neither of these reactive oxygen species was a major mediator in the Cu++-H2O2 oxidative system. A copper-oxygen complex may be directly involved in the initiation of peroxidation. Normal erythrocyte membranes and phospholipid liposomes also differ in their sensitivities toward external oxidative stress. In the absence of H2O2, CU++ (0.2 mM) was capable of catalyzing lipid peroxidation in liposomes, aged erythrocyte membranes and membranes from vitamin-E-deficient rats; however, freshly prepared membranes from control rats and liposomes containing alpha-tocopherol required H2O2 greater than 2 mM for the catalytic effect of Cu++ to be observed.
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PMID:Copper(II)-catalyzed lipid peroxidation in liposomes and erythrocyte membranes. 709 74

Peroxisomes appear profusely, in harmony with a marked enhancement of catalase activity level, in yeast cells growing on n-alkanes or higher fatty acids as the sole carbon source. Catalase (H2O2:H2O2 oxidoreductase, EC 1.11.1.6) was purified to homogeneity from the crude extract and from the peroxisome-containing particulate fraction of alkane-grown Candida tropicalis cells. The purified enzyme from each source was a similar protein of molecular weight 210000 composed of four identical subunits of molecular weight 54000, namely a kind of homotetramer. The enzyme contained one molecule of heme per subunit, giving the absorption spectrum characteristic of hemoprotein. Beta-(3,4-Dihydroxyphenyl)-L-alanine served as a substrate for the peroxidatic reaction by the enzyme. Ouchterlony double-diffusion analysis and immunochemical titration with rabbit antiserum against peroxisomal catalase of n-alkane-grown C. tropicalis have indicated that cytoplasmic catalase of the yeast is immunologically indistinguishable with peroxisomal catalase.
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PMID:Properties of catalase purified from whole cells and peroxisomes of n-alkane-grown Candida tropicalis. 711 50

Enhanced formation of nitric oxide (NO) by both the constitutive and the inducible isoforms of NO synthase (NOS) has been implicated in the pathophysiology of a variety of diseases, including circulatory shock. Non-isoform-selective inhibition of NO formation, however, may lead to side effects by inhibiting the constitutive isoform of NOS and, thus, the various physiological actions of NO. S-Methylisothiourea sulfate (SMT) is at least 10- to 30-fold more potent as an inhibitor of inducible NOS (iNOS) in immunostimulated cultured macrophages (EC50, 6 microM) and vascular smooth muscle cells (EC50, 2 microM) than NG-methyl-L-arginine (MeArg) or any other NOS inhibitor yet known. The effect of SMT on iNOS activity can be reversed by excess L-arginine in a concentration-dependent manner. SMT (up to 1 mM) does not inhibit the activity of xanthine oxidase, diaphorase, lactate dehydrogenase, monoamine oxidase, catalase, cytochrome P450, or superoxide dismutase. SMT is equipotent with MeArg in inhibiting the endothelial, constitutive isoform of NOS in vitro and causes increases in blood pressure similar to those produced by MeArg in normal rats. SMT, however, dose-dependently reverses (0.01-3 mg/kg) the hypotension and the vascular hyporeactivity to vasoconstrictor agents caused by endotoxin [bacterial lipopolysaccharide (LPS), 10 mg/kg, i.v.] in anesthetized rats. Moreover, therapeutic administration of SMT (5 mg/kg, i.p., given 2 hr after LPS, 10 mg/kg, i.p.) attenuates the rises in plasma alanine and aspartate aminotransferases, bilirubin, and creatinine and also prevents hypocalcaemia when measured 6 hr after administration of LPS. SMT (1 mg/kg, i.p.) improves 24-hr survival of mice treated with a high dose of LPS (60 mg/kg, i.p.). Thus, SMT is a potent and selective inhibitor of iNOS and exerts beneficial effects in rodent models of septic shock. SMT, therefore, may have considerable value in the therapy of circulatory shock of various etiologies and other pathophysiological conditions associated with induction of iNOS.
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PMID:Beneficial effects and improved survival in rodent models of septic shock with S-methylisothiourea sulfate, a potent and selective inhibitor of inducible nitric oxide synthase. 752 23

The Maillard reaction of glucose/amino acid produces components that induce strand breakage of supercoiled DNA. This study was designed to elucidate the structure of the active components and the mechanisms of their DNA strand breakage. When an aqueous mixture of glucose/glycine heated under reflux for 4 hr was extracted with ethyl acetate, the extract showed mutagenicity to Salmonella typhimurium TA100 and strand-breaking activity for supercoiled DNA. One of the components with DNA strand-breaking activity was isolated by repeated HPLC using a reverse phase column. The component was identified as 4-hydroxy-2-hydroxymethyl-5-methyl-3(2H)-furanone (HHMF), a fragrant component in the Maillard reaction mixture. HHMF was similarly produced in the reaction of glucose/alanine and fructose/glycine. DNA strand-breaking activity of the component at pH 7.4 increased with increasing dose of the component and with increasing incubation time. The strand-breaking activity of the component was greater at pH 7.4 than at pH 4.4 and 9.4; it was inhibited in the presence of superoxide dismutase, catalase, hydroxyl radical scavengers, spin-trapping agents, thiol compounds and metal chelators, and also by removal of dissolved oxygen from the reaction mixture. The strand-breaking activity was enhanced in the presence of ionic iron. Incubation of HHMF with 5,5-dimethyl-1-pyrroline N-oxide (DMPO) gave electron spin resonance signals characteristics of the DMPO-OH adduct, indicating generation of the hydroxyl radical. HHMF generated superoxide, hydrogen peroxide and then hydroxyl radical with the aid of a trace amount of metal ions, which effectively cleaved the DNA strand.
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PMID:DNA strand breaks induced through active oxygen radicals by fragrant component 4-hydroxy-2-hydroxymethyl-5-methyl-3(2H)-furanone in Maillard reaction of hexose/amino acid. 759 May 24

A critical step in the activation of cellular Ras is the release of bound GDP. Oligonucleotide primers derived from a mouse cDNA sequence homologous to the Saccharomyces cerevisiae CDC25 gene product were used to screen a human brain cDNA library. The cloning led to the isolation of a 2.8-kb cDNA predicted to encode a protein of 488 amino acids. This protein was produced in Escherichia coli as a glutathione S-transferase fusion protein and functioned in vitro as a specific guanine nucleotide-releasing factor. Polyclonal antibodies raised against the last 281 amino acids of the protein allowed a protein in the molecular weight range of 55 kDa to be identified in human cortex homogenates. Analysis by Northern blotting led to the identification of a 5.5-kb mRNA in brain poly(A)+ RNA. The functionality of the encoded protein was evaluated after expression in different cells: (i) in Saccharomyces cerevisiae the effects of the cdc25.5 and RAS2 Ala-22 mutations were reversed; (ii) in chinese hamster ovary cells, a RAS-responsive element was transactivated as demonstrated by the expression of a CAT reporter gene under the control of the polyomavirus enhancer. Finally, in situ hybridization on of human chromosomes revealed a localization on band 15q2.4.
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PMID:Identification of a human guanine nucleotide-releasing factor (H-GRF55) specific for Ras proteins. 768 28

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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