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:1.11.1.7 (peroxidase)
65,474 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

We studied the effects of granulocyte-macrophage colony-stimulating factor in burn patients. Serial measurements of granulocyte oxidative function were obtained in treated patients and in a group of controls matched for age and total burn size. The administration of granulocyte-macrophage colony-stimulating factor resulted in a 50% increase in mean leukocyte counts. Both groups showed significant baseline increases in granulocytic cytosolic oxidative function. Treated patients showed normal stimulated cytosolic oxidative function, which was significantly depressed compared with that of untreated patients. Myeloperoxidase activity was increased in treated patients during the first postburn week but then declined to normal levels. Untreated patients had a significant increase in myeloperoxidase activity for the first 3 weeks following injury. Untreated patients exhibited a significant decrease in superoxide activity during the second 3 weeks following injury. Treated patients demonstrated normal superoxide activity.
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PMID:Effects of granulocyte-macrophage colony-stimulating factor in burn patients. 184 29

Antineutrophil cytoplasmic autoantibodies (ANCA) are present in patients with systemic vasculitis with or without renal involvement. These antibodies were first seen using indirect immunofluorescence (IIF). Two types of patterns are seen on ethanol-fixed neutrophils: the cytoplasmic and the perinuclear pattern. The cytoplasmic pattern is called C-ANCA (classical or cytoplasmic ANCA) and the perinuclear, P-ANCA. Antibodies to a serine proteinase, called proteinase 3 or myeloblastin, give rise to the C-ANCA pattern, while antibodies to myeloperoxidase give rise to the P-ANCA pattern. Proteinase 3, as well as myeloperoxidase, is present in the primary granules of neutrophils, and the P-ANCA pattern is thus an artifactual staining pattern. Myeloperoxidase, which is a basic protein, redistributes during ethanol fixation from the primary granules to the negatively charged nucleus. As an alternative to the IF technique, several solid-phase assays have been developed using either 125I or enzyme-labeled secondary antibodies. Depending on the degree of purification of the antigens used, such assays may be used for screening or as a complement to the IF method. Today it is possible to directly screen for both types of ANCA using enzyme-linked immunosorbent assay (ELISA). Simultaneous screening for antiglomerular basement membrane (GBM) antibodies (Goodpasture antibodies) increases the diagnostic yield, especially in patients with renopulmonary syndromes.
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PMID:How are antineutrophil cytoplasmic autoantibodies detected? 186 72

A recent paper (Buchberger, W., 1988, J. Chromatogr. 432, 57) on lactoperoxidase-catalyzed bromination of tyrosine and thyroglobulin stated, without evidence, that thyroid peroxidase (TPO) is able to use bromide as a substrate. This was in disagreement with unpublished experiments previously performed in this laboratory, and we undertook, therefore, to examine this subject further. Highly purified porcine TPO was compared with lactoperoxidase (LPO) and chloroperoxidase (CPO) for ability to catalyze bromination of tyrosine, thyroglobulin, and bovine serum albumin (BSA). The incubation mixture contained 50-100 nM peroxidase, 10-500 microM 82Br-, tyrosine (150 microM), thyroglobulin (0.3 or 1 microM), or BSA (7.5 microM), and a source of H2O2. The latter was either generated by glucose (1 mg/ml)-glucose oxidase (0.5 or 1 micrograms/ml), or added initially as a bolus (100 microM). With TPO, formation of organically bound 82Br was undetectable under all conditions in the pH range 5.4-7.0. Lactoperoxidase and CPO, on the other hand, displayed considerable brominating activity. Lactoperoxidase was much more active at pH 5.4 than at pH 7.0 and was more active with BSA as acceptor than with tyrosine or thyroglobulin. The distribution of 82Br among the various amino acids in LPO-brominated thyroglobulin and BSA was determined by HPLC. As expected, monobromotyrosine and dibromotyrosine together comprised the greatest part of the bound 82Br. However, a surprisingly high percentage (20-25%) was present as monobromohistidine. Evidence was also obtained for the presence of a small percentage of the bound 82Br as tetrabromothyronine. Peroxidase-catalyzed bromination probably depends on the oxidation of Br- to Br+ by the Compound I form of the enzyme. Since oxidation of Br- to Br+ requires a stronger oxidant than oxidation of I- to I+, our results suggest that Compound I of LPO and of CPO has a higher oxidation potential than Compound I of TPO. In vivo experiments with rats on a low iodine diet injected with 82Br- showed that even under conditions of high stimulation by thyrotropic hormone, there is negligible formation of organic bromine in the thyroid. Measurements of thyroid:serum concentration ratios for 82Br- in similar rats provided no evidence that Br- is a substrate for the iodide transport system of the thyroid.
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PMID:Peroxidase-catalyzed bromination of tyrosine, thyroglobulin, and bovine serum albumin: comparison of thyroid peroxidase and lactoperoxidase. 189 6

Myeloperoxidase (MPO) plays an important role in the oxygen-dependent microbicidal mechanism of polymorphonuclear neutrophils. The purpose of our study was to investigate the therapeutic potency of human MPO preparations. This paper is to present our work on MPO purification and its identification. White blood cells, isolated freshly from normal donors, were lysed with cetyltrimethylammonium bromide to liberate myeloperoxidase. The purified MPO was obtained by 65% (NH4)2SO4 precipitation followed by separation over the Sephadex G150 column. These pure MPO preparations were green in color and had an A430/A280 nm of 0.68. The enzymatic activity was of 29.77 u/mg. The pure normal MPO was composed of a 59,000 MW peptide, a 13,500 MW peptide, and a 38,000 MW peptide when subjected to SDS-PAGE under reducing conditions. The study of the therapeutic effect of the pure MPO on mice with C. albicans infection is under way.
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PMID:[Purification and identification of human leukocyte myeloperoxidase]. 196 3

Pneumonic pasteurellosis was experimentally induced in calves by inoculation of 5 x 10(8) Pasteurella haemolytica organisms into the right diaphragmatic lung lobe. Blood and bronchoalveolar lavage fluid samples were obtained prior to inoculation and at postinoculation hour (PIH) 2, 4, and 6. Calves developed acute lung injury, characteristic of pneumonic pasteurellosis. Lesions were found only in the right diaphragmatic lobe. By PIH 4, significant (P less than 0.01) increases were detected in lavage fluid total cell count, neutrophil count, total protein and albumin concentrations, and alkaline phosphatase (ALP) and lactic dehydrogenase (LD) activities. Myeloperoxidase and elastase activities did not increase. Neutrophil depletion ameliorated the lung lesions and prevented the increase in lavage fluid cell count, total protein, and albumin concentrations and ALP and LD activities. Treatment with the iron chelator, deferoxamine mesylatehydroxyethyl starch, attenuated the increase in total protein and albumin concentrations and ALP and LD activities at PID 4, but not PIH 6. Treatment with a neutrophil function inhibitor, pentoxifylline, prevented the increase in lavage fluid neutrophil numbers, but accentuated the increase in total protein and albumin concentrations, and ALP, LD, myeloperoxidase, and elastase activities.
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PMID:Changes in blood and bronchoalveolar lavage fluid components in calves with experimentally induced pneumonic pasteurellosis. 201 47

Lactoperoxidase and thiocyanate content in goat milk from two Spanish breeds throughout 5 mo of lactation has been investigated. Mean lactoperoxidase for milk from Verata and Murciano-Granadina goats was .95 and 2.15 units/ml, respectively. Very low concentrations, .03 units/ml for Verata and .20 units/ml for Murciano-Granadina, were found for the first 24 h after kidding. Highest concentrations were detected at the end of lactation (135 to 150 d) for Verata and in midlactation (60 to 75 d) for Murciano-Granadina goats. Mean thiocyanate content was 5.76 ppm for Verata goats, without a distinct maximum throughout lactation, and 3.20 ppm for Murciano-Granadina goats, with maximum levels at final lactation stages. Activation of the lactoperoxidase system might be a useful procedure in preserving raw goat milk quality by addition of low levels of thiocyanate and hydrogen peroxide.
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PMID:Influence of breed, animal, and days of lactation on lactoperoxidase system components in goat milk. 207 11

The permeability of tight junctions to tracers having different molecular weights was investigated in the submandibular gland of rats stimulated parasympathetically, sympathetically, or both. Lactoperoxidase (82,000 daltons), horseradish peroxidase (40,000 daltons), and microperoxidase (1,630 daltons) were used as the tracers. The tracers were administered by close arterial infusion via the glandular artery, and their secretion into the saliva was quantified biochemically, and their secretory routes within the gland were determined histochemically at the electron microscopic level. Microperoxidase and horseradish peroxidase passed into the saliva by electrical stimulation of either the chorda or superior cervical ganglion, and the combined stimulation of both caused a larger output of both tracers. No output of lactoperoxidase into the saliva occurred with any type of nerve stimulation. Electron microscopic histochemical observations showed that molecules of molecular weight equal to or lower than that of horseradish peroxidase entered the lumen through the tight junctions between adjacent acinar cells following combined stimulations of chorda and superior cervical ganglion. These findings indicate that electrical stimulation of parasympathetic and sympathetic nerves causes an increase in tight junctional permeability of acinar cells to microperoxidase and horseradish peroxidase. Although the combined stimulation of parasympathetic and sympathetic nerves resulted in increased junctional permeability to these tracers, the junctions remained impermeable to larger molecules, i.e., lactoperoxidase.
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PMID:Autonomic regulation of tight junctional permeability in the rat submandibular gland. 213 Jan 59

An inflammatory response was elicited in the rabbit eye by intravitreal injection of endotoxin. The appearance in aqueous humor of selected metabolites of arachidonic acid metabolism at various times was correlated with the influx of protein and myeloperoxidase activity in the iris-ciliary body. After intravitreal injection of endotoxin, aqueous humor protein levels increased substantially within 2 hr. This aqueous humor protein increase occurred before a significant appearance of prostaglandin E2 (PGE2) in the aqueous humor. Myeloperoxidase activity in the iris-ciliary body, a measure of polymorphonuclear leukocyte (PMN) infiltration, showed little elevation until 6 hr after endotoxin injection and then increased rapidly through 24 hr. The appearance of the leukotriene B4 (LTB4) followed a similar time course: levels in the aqueous humor were partially elevated until 6 hr after endotoxin injection, when levels begin to rise rapidly. These findings are interpreted to demonstrate the dependence of PMN infiltration on the release and accumulation of LTB4; the initial breakdown of the blood-aqueous barrier and influx of protein appears to be independent of significant release of PGE2.
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PMID:Time course of rabbit ocular inflammatory response and mediator release after intravitreal endotoxin. 215 16

The myeloperoxidase catalysed oxidation of methimazole in the presence of NADH or GSH resulted in oxygen uptake suggesting that metabolism proceeded via a one electron mechanism. The GSH was oxidised to GSSG and the thiyl radical could be trapped with DMPO while NADH was oxidized to NAD+. Metabolism proceeded without the inactivation of the enzyme myeloperoxidase. Myeloperoxidase catalyzed oxidation of other substrates which proceed via one electron intermediates; 2,6-dimethylphenol, N,N,N',N'-tetramethyl-phenylenediamine and luminol, were all stimulated by methimazole providing further evidence for a methimazole free radical. The presence of iodide stimulated the oxidation of methimazole but inhibited the oxygen uptake in the presence of GSH or NADH suggesting that metabolism in this case proceeded by a two electron mechanism. In contrast, another S-thioureylene drug, thiourea; did not cause oxygen uptake when oxidised in the presence of GSH or NADH indicating that the myeloperoxidase oxidation of thiourea proceeded primarily by a two electron mechanism. The horseradish peroxidase catalysed one electron oxidation of p'p'-biphenol, and 3,3',5,5'-tetramethylbenzidine was reversibly inhibited by methimazole and thiourea by preventing the accumulation of oxidation products via reductive mechanisms whereas the reversible inhibition of guaiacol and luminol oxidation was the result of competitive inhibition. With p,p'-biphenol, and 3,3',5,5'-tetramethylbenzidine unstable adduct formation could be demonstrated.
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PMID:Myeloperoxidase catalysed cooxidative metabolism of methimazole: oxidation of glutathione and NADH by free radical intermediates. 215 13

Myeloperoxidase is a major protein component of the azurophilic granules (specialized lysosomes) of normal human neutrophils and serves as part of a potent bactericidal system in the host defense function of these cells. In normal, mature cells, myeloperoxidase occurs exclusively as a dimer of Mr 150,000 while in immature leukemia cells, there are both monomeric (Mr 80,000) as well as dimeric species. Like other lysosomal enzymes, myeloperoxidase is synthesized as a larger glycosylated precursor (Mr 91,000) that undergoes processing through single-chain intermediates (Mr 81,000 and 74,000) to yield mature heavy (Mr 60,000) and light (Mr 15,000) subunits. To study the assembly of dimeric myeloperoxidase, azurophilic granules were isolated from either unlabeled or pulse-labeled ([35S]methionine/cysteine) HL-60 cells, and myeloperoxidase was extracted and separated into monomeric and dimeric forms by FPLC gel filtration chromatography. Steady-state levels of dimeric and monomeric myeloperoxidase were found to account for 67% and 33%, respectively, of the total peroxidase activity and were correlated with the levels of associated heme as measured by absorption at 430 nm. Labeled myeloperoxidase polypeptides were immunoprecipitated using a monospecific rabbit antibody and were identified and quantitated by sodium dodecyl sulfate-polyacrylamide gel electrophoresis/fluorography and liquid scintillation counting. After a 2-h pulse, labeled myeloperoxidase species of Mr 74,000 and 60,000 were found in fractions coeluting with the monomeric form of myeloperoxidase.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Assembly of dimeric myeloperoxidase during posttranslational maturation in human leukemic HL-60 cells. 215 41


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