Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.11.1.7 (peroxidase)
 65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An enzyme system from Datura innoxia roots oxidizing formylphenylacetic acid ethyl ester was purified 38-fold by conventional methods such as (NH4)2SO4 fractionation, negative adsorption on alumina Cy gel and chromatography on DEAE-cellulose. The purified enzyme was shown to catalyse the stoicheiometric oxidation of formylphenylacetic acid ethyl ester to benzoylformic acid ethyl ester and formic acid, utilizing molecular O2. Substrate analogues such as phenylacetaldehyde and phenylpyruvate were oxidized at a very low rate, and formylphenylacetonitrile was an inhilating agents, cyanide, thiol compounds and ascorbic acid. This enzyme was identical with an oxidase-peroxidase isoenzyme. Another oxidase-peroxidase isoenzyme which separated on DEAE-chromatography also showed formylphenylacetic acid ethyl ester oxidase activity, albeit to a lesser extent. The properties of the two isoenzymes of the oxidase were compared and shown to differ in their oxidation and peroxidation properties. The oxidation of formylphenylacetic acid ethyl ester was also catalysed by horseradish peroxidase. The Datura isoenzymes exhibited typical haemoprotein spectra. The oxidation of formylphenylacetic acid ethyl ester was different from other peroxidase-catalysed reactions in not being activated by either Mn2+ or monophenols. The oxidation was inhibited by several mono- and poly-phenols and by catalase. A reaction mechanism for the oxidation is proposed.
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PMID:Oxidase-peroxidase enzymes of Datura innoxia. Oxidation of formylphenylacetic acid ethyl ester. 0 Sep 97

Effect of IAA (10(-10)-10(-3) M) on photophosphorylation, NADP reduction and the oxygen exchange is investigated. It is shown that low concentrations of IAA (10(-10)-10(-7) M) increase the photophosphorylation reaction and the flow of electrones to NADP under the phosphorylation conditions in the chloroplasts, and their effect on the O2 exchange is not the same in different types of photophosphorylation. It is supposed that the effect of IAA on the photophosphorylation is connected with H292 metabolism in chloroplasts and with catalase and peroxidase functions.
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PMID:[Effect of IAA on the photophosphorylation of pea isolated chloroplasts]. 0 32

The lacrimal gland (Glandula orbitalis externa) of rat contains both peroxidase and catalase and was used as a model for biochemical and cytochemical distinction between peroxidase and catalase. Both enzymes were isolated by ammonium sulfate precipitation from tissue homogenates, and the effects of fixation with glutaraldehyde and various conditions of incubation were investigated colorimetrically using DAB as hydrogen donor. The lacrimal gland peroxidase is strongly inhibited by glutaraldehyde treatment. In contrast, for catalase the fixation with glutaraldehyde is the prerequistie for demonstration of its peroxidatic activity. The maximal peroxidatic activity was obtained after treatment of catalase with 3% glutaraldehyde, higher concentrations being inhibitory. For lacrimal gland peroxidase, the maximal rate of oxidation of DAB is at pH 6.5, whereas for catalase it is at pH 10.5. The optimal concentration of H2O2 for lacrimal gland peroxidase is at 10(-3)M and for peroxidatic activity of catalase at 10(-1)M. These optimal conditions obtained biochemically were applied to tissue sections of rat lacrimal gland. After the fixation of tissue with a low concentration of glutaraldehyde and incubation in the DAB medium at neutral pH containing 10(-3)M H2O2 (Peroxidase medium), the reaction product was localized in the cisternae of the rough endoplasmic reticulum, in elements of the Golgi apparatus, and in secretory granules. After the fixation of tissue with 3% glutaraldehyde and incubation in the DAB-medium containing 10(-1)M H2O2 and at pH 10.5 (catalase medium), the staining in the endoplasmic reticulum, the Golgi-apparatus and in secretory granules was completely inhibited and reaction product was localized exclusively in small (0.2-0.5 mu) particles similar to small peroxisomes described in various other cell-types.
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PMID:Intracellular distinction between peroxidase and catalase in exocrine cells of rat lacrimal gland: a biochemical and cytochemical study. 0 18

Two strains of Escherichia coli and one strain each of Salmonella typhimurium and Pseudomonas aeruginosa were killed by the bactericidal activity of the lactoperoxidase-thiocyanate-hydrogen peroxide system in milk and in a synthetic medium. H2O2 was supplied exogenously by glucose oxidase, and glucose was produced at a level which was itself noninhibitory. Two phases were distinguished: the first phase was dependent on the oxidation of SCN(-) by lactoperoxidase and H2O2, which was reversed by reducing agent, and the second phase was dependent on the presence of accumulated H2O2, which was reversed by catalase. The latter enzyme could also reverse the first phase, but only when present in excessive and unphysiological levels. The bactericidal activity was greatest at pH 5 and below, and it depended on the SCN(-)concentration and on the number of organisms. Since raw or heated milk neutralizes the acid barrier against infection in the stomach, the bactericidal system discussed may contribute to the prevention of enteric infections in neonates.
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PMID:Nonspecific bactericidal activity of the lactoperoxidases-thiocyanate-hydrogen peroxide system of milk against Escherichia coli and some gram-negative pathogens. 0 74

The role of peroxidase-mediated bacterial killing by rabbit alveolar macrophages was examined. During 3 h of incubation in vitro, alveolar macrophages ingested and killed greater than 88% of the Streptococcus faecalis, Proteus mirabilis, or Streptococcus pneumoniae present in the incubation mixture. Preincubation of alveolar macrophages with inhibitors of catalase, 3-amino-1,2,4-triazole or sodium nitrite, did not alter their bactericidal potential. Iodination of ingested zymosan particles, a peroxidase-dependent and hydrogen peroxide-dependent reaction, was not observed, in spite of vigorous phagocytosis by alveolar macrophages. Furthermore, iodination by alveolar macrophages was not significantly increased when peroxidase-coated zymosan particles were ingested. The results suggest that hydrogen peroxide may not be available to the phagocytic vacuole for microbial killing. Since tetrazolium dye reduction reflects the activity of an oxidase responsible for stimulated oxygen consumption by polymorphonuclear leukocytes, this reaction was also measured. Rabbit alveolar macrophages incubated with latex particles did not exhibit an increased dye reduction compared with resting cells. The absence of significant stimulation of tetrazolium dye reduction indicates that the oxidase reaction does not occur in the proximity of the phagocytic vacuole of alveolar macrophages.
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PMID:Bactericidal mechanisms in rabbit alveolar macrophages: evidence against peroxidase and hydrogen peroxide bactericidal mechanisms. 0 33

Four manned experiments (4 test subjects participating in each) were carried out in a chamber of 24 m3. The effect of CO at a concentration of 10 to 45 mg/m3 on the content of carboxyhemoglobin in the blood, nonhemoglobin iron in the plasma, CO in the breathing air, catalase and peroxidase activity was studied. A correlation was found between these parameters and CO concentration in the atmosphere and exposure time. It was demonstrated that a continuous exposure (up to 90 days) to CO at a concentration of 10 mg/m3 under favorable microclimatic conditions produced no significant effect on the above mentioned biochemical paramters.
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PMID:[Relationship of the content of carboxyhemoglobin in the blood and of carbon monoxide in the expired air of test subjects to the CO concentration in the air of a hermetic chamber]. 1 44

Some properties of a number of enzymes immobilized by the diazotized m-diaminobenzene (dDAB) method are described. The pH-activity profiles of beta-D-glucosidase, glucoamylase, peroxidase, uricase, and D-glucose oxidase were virtually unchanged on immobilization while those of catalase and dextranase were significantly altered. beta-D-Glucosidase, glucoamylase, and glucose oxidase were found to be more susceptible to denaturation on lyophilization when immobilized than in the native state; however, sorbitol had a marked protective effect in every case examined. Sorbitol was also found to exert a stabilizing effect when lyophilized immobilized preparations were stored. Immobilization marginally improved the stabilities of a number of enzymes to heating at 60 degrees at pH 8.0. The usefulness for continuous reaction of a column of glucoamylase attached to celite was established. The reuse of the solid supports was demonstrated.
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PMID:Properties of enzymes immobilized by the diazotized m-diaminobenzene method. 1 49

A procedure has been developed for the partial purification from Chlorella vulgaris of an enzyme which catalyzes the formation of HCN from D-histidine when supplemented with peroxidase of a metal with redox properties. Some properties of the enzyme are described. Evidence is presented that the catalytic activity for HCN formation is associated with a capacity for catalyzing the oxidation of a wide variety of D-amino acids. With D-leucine, the best substrate for O2 consumption, 1 mol of ammonia is formed for half a mol of O2 consumed in the presence of catalase. An inactive apoenzyme can be obtained by acid ammonium sulfate precipitation, and reactivated by added FAD. On the basis of these criteria, the Chlorella enzyme can be classified as a D-amino acid oxidase (EC 1.4.3.3). Kidney D-amino acid oxidase and snake venom L-amino acid oxidase, which likewise form HCN from histidine on supplementation with peroxidase, have been compared with the Chlorella D-amino acid oxidase. The capacity of these enzymes for causing HCN formation from histidine is about proportional to their ability to catalyze the oxidation of histidine.
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PMID:A D-amino acid oxidase from Chlorella vulgaris. 1 7

The air oxidation of procarbazine in the presence of Ti(IV) was examined as a model system for the effects titanium has on oxidative processes and intermediates involving molecular oxygen. It was found that Ti(IV) inhibited oxidation when the substrate, procarbazine, was coordinated to titanium. This inhibition was most prominent (reduction of overall rate constant by a factor of 10(2)) in its interference with Cu(II) catalyzed oxidation of the substrate whole oxidation by the neutral species O2 was only slightly inhibited (factor of 2). However, when Mn(II) was used to catalyze the oxidation of procarbazine by air, titanium enhanced the catalytic effect of Mn(II) by a factor of 10(2). This enhancement was found to be due to Ti(IV) catalysis of the air oxidation of Mn(II), and the effect was found to be inhibited by catalase but not superoxide dismutase or peroxidase. These results are discussed in terms of a Ti(IV) ability to activate molecular oxygen and its ability to form oxygen free-radical complexes.
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PMID:Oxidation of procarbazine in the presence of Ti(IV). 1 28

A new enzyme which catalyzes the oxidation of the side chain of tryptophan and other indole derivatives, has been purified to apparent homogeneity from Pseudomonas and crystallized. The overall purification was about 25-fold with a yield of 4.5%. The purified enzyme was apparently homogeneous as judged by polyacrylamide gel electrophoresis. The molecular weight estimated by gel filtration was approximately 280,000 and sedimentation coefficient (S20,w) was 11 by sucrose density gradient ultracentrifugation. The absorption spectra indicated that the enzyme was a hemoprotein. The purified enzyme was shown to catalyze the reaction in which 1 mol each of NH3 and CO2 was formed at the expense of 1 mol each of L-tryptophan and molecular oxygen. Neither peroxidase nor catalase activity was detected in the purified enzyme and no formation of H2O2 was observed during the enzyme reaction. The product(s) of the reaction was unstable but was converted to and was identified as its stable quinoxaline derivative, 2-(3-indolyl)quinoxaline, in the presence of o-phenylenediamine. These results indicate that the product of the reaction was 3-indolylglycoaldehyde or 3-indolylglyoxal. A variety of other indole derivatives such as D-tryptophan, 5-hydroxyl-L-tryptophan, tryptamine, serotonin, melatonin, N-acetyl-L-tryptophan, N-acetyl-L-tryptophanamide, 3-indoleacetamide, 3-indolelactic acid, 3-indolepropionic acid, 3-indoleethanol, and skatole were also substrates.
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PMID:Crystalline hemoprotein from Pseudomonas that catalyzes oxidation of side chain of tryptophan and other indole derivatives. 1 95


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