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)

There has been disagreement as to the identity of the enzyme responsible for the peroxidate activity in luminal epithelial cells of distal ducts of salivary glands; both peroxidase and catalase could be responsible. Our immunocytochemical investigations using anti-catalase antibodies demonstrate that there are high levels of catalase in these cells in the mouse submandibular gland confirming previous enzyme histochemical studies from this laboratory. Since only relatively small amounts of lactoperoxidase are observed in ductal cells by conventional histochemistry or immunocytochemistry, there can be little doubt that the majority of the peroxidatic activity in striated and excretory duct luminal epithelial cells is due to catalase.
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PMID:Catalase in salivary gland striated and excretory duct cells. III. Immunocytochemical demonstration with fluorescein and peroxidase-labelled antibodies. 7 20

Macromolecular tracers were injected into the tongue or around a crush in mouse hypoglossal nerves. At various times thereafter, the tracers were histochemically localized on the basis of peroxidase activity. The distribution of reaction product was then examined using light microscopy in order to study the influence of molecular charge and size on uptake and retrograde axonal transport from the periphery or from the crushed axon. Of various proteins with peroxidase activity, horseradish peroxidase and cytochrome-c showed the greatest penetration into axons proximal to the crush. Following injection into the tongue, intra-axonal cytochrome-c was detectable in some of the peripheral branches but not any of the other proteins. Retrograde transport to the nerve cell bodies was demonstrated for horseradish peroxidase and cytochrome-c, both from the tongue and from the axonal crush but not for microperoxidase, myoglobin, hemoglobin, lactoperoxidase and catalase. The number of neuronal cell bodies having detectable reaction product was higher for peroxidase-injected than for cytochrome-c-injected animals. Ferritin and iron-dextran (Imferon) also accumulated in hypoglossal neurons, but this could be detected only after repeated injections into the tongue. Uptake and retrograde transport from the tongue or from the crush occurred both for anionic and for cationic horseradish peroxidase. This is interpreted as evidence against absolute specificity in the uptake and transport of macromolecules on the basis of electrical charge.
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PMID:Uptake and retrograde axonal transport of various exogenous macromolecules in normal and crushed hypoglossal nerves. 8 Oct 88

Elucidation of the ultrastructural basis of vascular permeability was aided by the development of cytochemical techniques for visualizing the distribution, within the vessel wall, of intravenously injected peroxidatic enzymes of varying molecular size. Tracer enzymes available range from 10 A (hemeoctapeptide) to 52 A (catalase) effective molecular radius. The use of enzymatic probe molecules assumes a thorough characterization of: (a) the molecular charge (isoelectric point of the native enzyme, and when feasible, its polyanionic and polycationic derivatives; (b) effective molecular radius (ae); (c) peroxidase activity (to detect by spectrophotometry of DAB-oxidizing activity, the optimal pH, temperature, and enzyme concentration to be employed in the cytochemical procedure). Molecular shape and state of dispersion of the enzymatic probes should be determined by gel chromatography and spectrophotometry of both the tracer solution and aliquots of blood plasma collected after i.v. injection of the tracer. Conditions required for the probe administration include: (a) the investigation of potential side effects (tests for toxicity and vascular leakage) and (b) estimation of the tracer volume and concentration which does not affect significantly the blood volume and osmotic pressure. Determination in vitro of the crosslinking of tracer molecules induced by the aldehyde fixative to be employed, also gives an indication on potential diffusion artifacts. Based on the information thus obtained, the design of the cytochemical procedure should also take into account the possible use of methods for enhancing the peroxidatic reaction product: nitrogenous ligands (imidazole, diaminopyrimidine, histidine) or polyphenolic mordants (galloylglucoses). The usefulness of peroxidatic tracers in the investigation of vascular permeability is exemplified by some results obtained on the microvascular endothelium in vivo (trasncytosis, intercellular pathway, etc.), and on endothelial cells isolated from heart microvasculature.
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PMID:Enzymatic tracers in the study of vascular permeability. 9 73

A sensitive method for evaluating extracellular parasite viability was used to determine the in vitro susceptibility of virulent Toxoplasma gondii to selected oxygen intermediates. By acridine orange fluorescent staining criteria, toxoplasmas were resistant to up to either 10(-3) M reagent H2O2 or H2O2 generated by glucose-glucose oxidase. In keeping with a lack of sensitivity to H2O2, toxoplasmas contained endogenous catalase (5.7 x 10(-4) Baudhuin units/10(6) organisms). The addition of a peroxidase and halide, however, markedly accelerated killing and lowered the H2O2 requirement by 1,000-fold. In contrast, toxoplasmas were promptly killed after exposure to products generated by xanthine (1.5 x 10(-4) M) and xanthine oxidase (50 micrograms). The inhibition of this system's microbicidal activity by scavengers of O2- (superoxide dismutase) and H2O2 (catalase) indicated that although neither O2- nor H2O2 were toxoplasmacidal, their interaction was required for parasite killing. Quenching OH. and 1O2, presumed products of O2--H2O2 interaction, by mannitol, benzoate, diazabicyclooctane, and histidine, also inhibited toxoplasma killing by xanthine-xanthine oxidase. These findings suggested that O2- and H2O2 functioned in precursor roles and that OH. and 1O2 were toxoplasmacidal. The capacity of normal peritoneal macrophages to pinocytose an oxygen intermediate scavenger, soluble catalase, was also demonstrated. Appreciable extraphagosomal concentrations of catalase were achieved by exposing macrophages to 1 mg/ml of the enzyme for 3 h. Maintenance of high intracellular levels required constant exposure because interiorized catalase was rapidly degraded.
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PMID:Macrophage oxygen-dependent antimicrobial activity. I. Susceptibility of Toxoplasma gondii to oxygen intermediates. 9 21

Isolates of Cephalosporium maydis varied in their pathogenicity to D.C. 67 maize cultivar from highly to weakly pathogenic. Highly pathogenic isolates showed lower activity of polyphenol oxidase, peroxidase, cytochrome oxidase, and beta-glucosidase enzymes and higher activity of catalase and dehydrogenase than weakly pathogenic isolates. Enzymes production by the tested isolates increased as the culture age increased; except in case of catalase enzyme, the reverse action was detected. The role of these enzymes in the virulence of C. maydis is suggested and discussed.
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PMID:The role of certain oxidative enzymes, catalase, and beta-glucosidase on virulence of Cephalosporium maydis. 9 10

The effects of K2PtCl4, cis-Pt(NH3)2Cl2, and trans-Pt(NH3)2Cl2 on the activities of glyceraldehyde-3-phosphate dehydrogenase, glucose-6-phosphate dehydrogenase, dihydrofolate reductase, fructose-1,6-bisphosphate aldolase, catalase, tyrosinase, and peroxidase have been investigated. All of the enzymes which are thought to have essential sulfhydryl groups (glyceraldehyde-3-phosphate dehydrogenase, aldolase, and glucose-6-phosphate dehydrogenase) were significantly inhibited by K2PtCl4. The other four enzymes studied are not known to have essential sulfhydryl groups, and were not significantly affected by the Pt compounds under the conditions employed. Glyceraldehyde-3-phosphate dehydrogenase was the only enzyme inhibited by all three Pt compounds tested, with K2PtCl4 being the most effective and cis-Pt(NH3)2Cl2 the least effective inhibitor. Semilogarithmic plots of residual activity versus inhibition time indicated that the inhibition reactions were not simple first-order processes, except for the inhibition of glucose-6-phosphate dehydrogenase by K2PtCl4 which appeared to be first-order with respect to enzyme concentration.
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PMID:The effects of platinum complexes on seven enzymes. 11 85

The oxidase-peroxidase from Datura innoxia which catalyses the oxidation of formylphenylacetic acid ethyl ester to benzoylformic acid ethyl ester and formic acid was also found to catalyse the oxidation of NADH in the presence of Mn2+ and formylphenylacetic acid ethyl ester. NADH was not oxidized in the absence of formylphenylacetic acid ethyl ester, although formylphenylacetonitrile or phenylacetaldehyde could replace it in the reaction. The reaction appeared to be complex and for every mol of NADH oxidized 3-4 g-atoms of oxygen were utilized, with a concomitant formation of approx. 0.8 mol of H2O2, the latter being identified by the starch-iodide test and decomposition by catalase. Benzoylformic acid ethyl ester was also formed in the reaction, but in a nonlinear fashion, indicating a lag phase. In the absence of Mn2+, NADH oxidation was not only very low, but itself inhibited the formation of benzoylformic acid ethyl ester from formylphenylacetic acid ethyl ester. A reaction mechanism for the oxidation of NADH in the presence of formylphenylacetic acid ethyl ester is proposed.
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PMID:Oxidase-peroxidase enzymes of Datura innoxia. Oxidation of reduced nicotinamide-adenine dinucleotide in the presence of formylphenylacetic acid ethyl ester. 17 92

The mechanism of steroid hydroxylation in rat liver microsomes has been investigated by employing NaIO4, NaClO2, and various organic hydroperoxides as hydroxylating agents and comparing the reaction rates and steroid products formed with those of the NADPH-dependent reaction. Androstenedione, testosterone, progesterone, and 17beta-estradiol were found to act as good substrates. NaIO4 was by far the most effective hydroxylating agent followed by cumene hydroperoxide, NADPH, NaClO2, pregnenolone 17alpha-hydroperoxide, tert-butyl hydroperoxide, and linoleic acid hydroperoxide. Androstenedione was chosen as the model substrate for inducer and inhibitor studies. The steroid was converted to its respective 6beta-, 7alpha, 15-, and 16alpha-hydroxy derivatives when incubated with microsomal fractions fortified with hydroxylating agent. Evidence for cytochrome P-450 involvement in androstenedione hydroxylation included a marked inhibition by substrates and modifiers of cytochrome P-450 and by reagents which convert cytochrome P-450 to cytochrome P-420. The ratios of the steroid products varied according to the type of hydroxylating agent used and were also modified by in vivo phenobarbital pretreatment. It was suggested that multiple forms of cytochrome P-450 exhibiting different affinities for hydroxylating agent are responsible for these different ratios. Horse-radish peroxidase, catalase, and metmyoglobin could not catalyze androstenedione hydroxylation. Addition of NaIO4, NaClO2, cumene hydroperoxide and other organic hydroperoxides to microsomal suspensions resulted in the appearance of a transient spectral change in the difference spectrum characterized by a peak at about 440 nm and a trough at 420 nm. The efficiency of these oxidizing agents in promoting steroid hydroxylation in microsomes appeared to be related to their effectiveness in eliciting the spectral complex. Electron donors, substrates, and modifiers of cytochrome P-450 greatly diminished the magnitude of the spectral change. It is proposed that NaIO4, NaClO2, and organic hydroperoxides promote steroid hydroxylation by forming a transient ferryl ion (compound I) of cytochrome P-450 which may be the common intermediate hydroxylating species involved in hydroxylations catalyzed by cytochrome P-450.
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PMID:The involvement of cytochrome P-450 in hepatic microsomal steroid hydroxylation reactions supported by sodium periodate, sodium chlorite, and organic hydroperoxides. 17 55

Polymorphonuclear leukocytes isolated from chicken peritoneal exudates have been found to catalyze cyanide-insensitive stimulation of respiration and the hexose monophosphate shunt upon exposure to heat-inactivated Staphylococcus aureus. However, there was no demonstrable formate oxidation concomitant with phagocytosis in either the presence or absence of exogenous catalase. Moreover, chicken polymorphonuclear leukocytes failed to oxidize scopoletin concomitant with phagocytosis in the presence of horseradish peroxidase. While oxygen uptake was increased 2- to 3-fold by the stimulus of phagocytosis, the oxidation of [1-(14)C]glucose was increased approximately 20-fold. The cells contain two mechanisms, a glutathione reductase-glutathione peroxidase system and an NADPH-NAD+ transhydrogenase, each of which is present in sufficient capacity to accommodate the enhanced shunt activity. Although chicken polymorphonuclear leukocytes were found to possess a substantial capacity to catalyze the cyanide-insensitive oxidation of either NADH or NADPH, the total or specific activities of such processes were not demonstrably affected by phagocytosis.
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PMID:Chicken neutrophils: oxidative metabolism in phagocytic cells devoid of myeloperoxidase. 17 90

Cytochemical and ultrastructural analysis of wild-type cells of Saccharomyces cerevisiae, grown aerobically in a glucose-limited chemostat, shows that cytochrome c peroxidase is localized between the membranes of the cristae, that is, in the intracristal space. This enzyme is thus positioned appropriately within the organelle to act as an alternate terminal oxidase for the respiratory chain. The proximity of the peroxidase to major sites of generation of its two substrates may account for the small leakage of hydrogen peroxide from yeast mitochondria, as compared with the larger outflow from mammalian mitochondria. In the cytoplasmic petite mutant, gross distortion of promitochondrial membrane arrangement is evident. Nevertheless, cytochrome c perioxidase activity is present in the same amounts as is found in wild-type cells, and is localized predominantly within annuli of membrane which constitute the promitochondria in these cells. No unequivocal evidence was obtained for the localization of catalase in microbodies or other organelles in either wild-type or petite cells.
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PMID:The intramitochondrial location of cytochrome c peroxidase in wild-type and petite Saccharomyces cerevisiae. 17 51


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