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)

Oligonucleotides were end-labelled with digoxigenin (DIG), chemically at the 5'-end or enzymically at the 3'-end. Following specific in situ hybridization of these probes to intracellular rRNA molecules, the hybrids were detected with anti-DIG Fab fragments labelled with fluorescent dyes. The antibody fragments penetrated through the bacterial cell periphery and specifically bound to their antigens. Probe-conferred and non-specific fluorescence per cell were quantified by flow cytometry and compared to values obtained with end-labelled fluorescent probes. The DIG reporter molecules could also be detected in whole fixed cells by antibodies labelled with either alkaline phosphatase or horseradish peroxidase. The penetration of the large antibody-enzyme complexes into the cells required lysozyme/EDTA treatment prior to the hybridization and has so far only been achieved for Gram-negative bacteria. This technique has the potential for significant signal amplification as compared to the fluorescently end-labelled oligonucleotides hitherto used for single cell identification in microbial ecology. Moreover, it can be used instead of fluorescent assays in natural samples showing autofluorescence.
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PMID:Identification of single bacterial cells using digoxigenin-labelled, rRNA-targeted oligonucleotides. 172 65

The effect of four myotoxins isolated from Bothrops snake venoms on the release of peroxidase trapped in large multilamellar liposomes was studied and correlated to their phospholipase A2, myotoxic and anticoagulant activities. The four myotoxins affected negatively-charged liposomes in a dose-dependent way, having no effect on positively-charged liposomes. Conditions that inhibited phospholipase A2 activity, i.e., substitution of calcium by EDTA, reduced liposome-disrupting activity of Bothrops asper myotoxin I and Bothrops atrox myotoxin, both of which have high phospholipase A2 activity, but did not affect the action of B. asper myotoxin II and Bothrops moojeni myotoxin II, which have extremely low phospholipase A2 activity. However, all myotoxins disrupted to some extent negatively-charged liposomes under conditions where phospholipase A2 activity was abolished. Since these toxins behave as amphiphilic proteins in charge-shift electrophoresis, it is suggested that membrane-disorganization is at least partially due to a non-enzymatic penetration and alteration of bilayers. There was no strict correlation between liposome-disrupting activity and myotoxicity in vivo. Thus, although both effects probably depend on the toxins' ability to disturb membranes, it is likely that variation in complexity between skeletal muscle plasma membrane and liposome bilayers are the basis for this difference. The anticoagulant effect seems to depend on the ability of the toxins to enzymatically degrade phospholipids, since only B. asper myotoxin I and B. atrox myotoxin prolonged the plasma recalcification time.
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PMID:The effect of myotoxins isolated from Bothrops snake venoms on multilamellar liposomes: relationship to phospholipase A2, anticoagulant and myotoxic activities. 176 57

In the presence of the Cu(I)-chelating agent neocuproine (2,10-dimethyl-1,9-phenanthroline) hydrogen peroxide acts as a reductant of Cu(II). The reaction does not proceed in the absence of neocuproine and the addition of EDTA to the reaction mixture prior to addition of Cu(II) also inhibits the reduction. Colour development can be arrested and stabilized by addition of EDTA. The reaction can be used to estimate hydrogen peroxide concentrations in the range 0.68-6.8 micrograms/ml and glucose concentrations in the range 3.6-36 micrograms/ml (20-200 microM). Horseradish peroxidase is not required for the peroxide assay but glucose oxidase must be used for glucose estimations. Thermostable cellulase activity has been estimated at 60 degrees C against cellobiose, carboxymethylcellulose and cellulose substrates by estimation of the glucose released from the substrates.
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PMID:Estimation of cellulase activity using a glucose-oxidase-Cu(II) reducing assay for glucose. 177 Jan 97

Renal transplant recipients have a high incidence of cutaneous complications such as neoplasia and viral or fungal infections. Morphologic alterations of epidermal Langerhans cells (LC) have furthermore been described in these patients. Since these changes have been mainly found in sun-exposed skin, a direct effect of immunosuppressive therapy remains a matter of discussion. A quantitative and morphometric study of epidermal LC in non-exposed skin was performed in 28 renal transplant patients (RTP). RTP were divided in two groups according to immunosuppressive treatment: group A; azathioprine + prednisone (14 cases) and group B; cyclosporine + prednisone (14 cases). Twenty sex-age matched non-immunosuppressed patients acted as controls (group C). Epidermal sheets were obtained by incubation in EDTA and stained for ATPase activity and with the monoclonal antibody T6 (CD1) using the avidin-biotin peroxidase method. Langerhans cells were counted using a calibrated graticule (400x) and expressed as the mean number of LC/mm2. The mean area of the LC and the number of primary dendrites (pd) and secondary dendrites (sd) were determined with a morphometer adapted to an Apple II computer. The mean number of positive cells in controls was: ATPase, 677 +/- 157; T6, 695 +/- 164. Patients in group A had the maximum reduction in both ATPase and T6 LC density (ATPase, 339 +/- 142; T6, 402 +/- 194). Patients in group B had an intermediate reduction in the number of LC (ATPase, 494 +/- 121; T6, 529 +/- 112).(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Quantitative and morphometric analysis of Langerhans cells in non-exposed skin in renal transplant patients. 183 Mar 23

The haem enzyme myeloperoxidase (MPO) (EC 1.11.1.7) with a spectral A430/A280 ratio greater than 0.7 and a specific activity of 125 U/mg was purified from isolated human neutrophils. To obtain a radioimmunoassay (RIA) for this enzyme, a specific antiserum against human neutrophil MPO was raised in rabbits and used at an initial dilution of 1/10,000. MPO labelled with 125iodine by a technique of self-labelling in the presence of H2O2, had a specific activity of 24 mCi/mg. After incubation at room temperature (2 h) and separation by double antibody precipitation in the presence of polyethylene glycol, the sensitivity of the RIA was 21 ng/ml. The RIA showed good precision and accuracy with intra- and interassay coefficients of variation of less than 7% for MPO concentrations ranging from 100 to 800 ng/ml, and satisfactory recoveries of known amounts of exogenous MPO in plasma. For the measurement of MPO in blood, the best sampling technique was to collect blood into EDTA. Rapid centrifugation (within 20 min) was necessary for blood collected into heparin. Mean MPO values in normal individuals were 340 +/- 98 ng/ml in EDTA plasma (n = 152) and 332 +/- 82 ng/ml in heparinized plasma (n = 34). When MPO was measured 12-6 h after injury in critically ill patients high values (above 1000 ng/ml) were found in 6/15 patients with multiple injuries. In patients with sepsis (n = 22), MPO values were always above 1000 ng/ml.
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PMID:Fast double antibody radioimmunoassay of human granulocyte myeloperoxidase and its application to plasma. 184 40

Aluminum intoxication is currently thought to play a major role in the development of Alzheimer's disease and in certain pathologic manifestations seen during long-term hemodialysis and aging. The hypothesis that aluminum toxicity is mediated via an increased free radical production was tested by studying the effects of two aluminum and five other metallic compounds on the production of luminol-enhanced chemiluminescence (LECL) by human neutrophils. AlCl3, Al2(SO4)3 and FeCl3 were found to stimulate LECL production by human neutrophils whereas FeCl2, CuCl, CuCl2, AuCl3 were inactive. Metal chelators such as Desferal, EDTA and DETAPA suppressed aluminum-induced stimulation and depressed cell-dependent LECL below basal levels. Sodium azide and Cytochalasin B greatly depressed both basal and aluminum-induced stimulation of LECL production, suggesting that, in this system, most of this stimulation was due to myeloperoxidase. These results suggest that high tissue aluminum concentrations may induce cell-tissue lesions by stimulating local production or release of mediators of tissue damage.
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PMID:Aluminum salts stimulate luminol-enhanced chemiluminescence production by human neutrophils. 190 35

A severe dysfunction in the cellular response of human polymorphonuclear leukocytes (PMNL) to non-opsonized zymosan was observed under a deficiency of extracellular Mg2+. The phagocytosis-association native (luminol-independent) luminescence (NL), as well as luminol-dependent luminescence (LDL) (detected simultaneously and discriminated by spectral methods), was strongly inhibited. Apart from a general decrease of total light production, a Mg2+-concentration-dependent delay of the maximum of NL and LDL was observed. A disorder in recruitment of activated membrane-bound NADPH-oxidase of PMNL is suggested. The presence of extracellular Ca2+ did not compensate for the Mg2+ deficit. In the presence of Mg2+ only a slight Ca2+-dependent reduction of NL was obtained, but Ca2+ seemed to selectively promote LDL. This may indicate a positive influence of Ca2+ on the myeloperoxidase release from the cells. Experiments with the metalions-chelating agents EDTA and EGTA, which complex Mg2+ to differing extents, confirmed the important role of Mg2+ in PMNL-activation by non-opsonized zymosan.
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PMID:Magnesium-dependent induction of phagocytosis-associated chemiluminescence of adherent human polymorphonuclear leukocytes by non-opsonized zymosan. 210 60

Dithionite is often used to deoxygenate aqueous solutions because it reacts readily with oxygen. However, milder reducing agents, that do not ordinarily react readily with oxygen, may do so in the presence of an appropriate redox catalyst. We show that dithiothreitol reacts rapidly with oxygen in concentrated hemoglobin solutions to produce a mixture of deoxy-, met- and sulf-hemoglobin. The reaction in neutral phosphate buffer is not significantly affected by superoxide dismutase, benzoate or EDTA. However, addition of catalase or horseradish peroxidase decreases the proportions of met- and sulf-hemoglobin produced. We conclude that both hemoglobin and horse radish peroxidase accept dithiothreitol as the reducing substrate in heme catalyzed reactions with their respective oxidizing substrates (dioxygen and hydrogen peroxide). As a result, deoxy-hemoglobin suitable for physical studies can be prepared with a combination of a stoichiometric excess of dithiothreitol and a catalytic amount of horse radish peroxidase.
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PMID:Gentle chemical deoxygenation of hemoglobin solutions. 212 39

The ability of various reactive oxygen species and serine proteases to activate latent collagenase (matrix metalloproteinase-1) purified from human neutrophils was examined. Latent 70-75 kD human neutrophil collagenase (HNC) was efficiently activated by known non-proteolytic activators phenylmercuric chloride (an organomercurial compound) and gold thioglucose (Au(I)-salt). Corresponding degree of activation was achieved by reactive oxygen species including hypochlorous acid (HOCl), hydrogen peroxide (H2O2) and hydroxyl radical generated by hypoxanthine/xanthine oxidase (HX/XAO). The presence of trace amounts of iron and EDTA were necessary and even enhanced H2O2 induced activation of latent HNC. This activation could be abolished by an iron chelator desferrioxamine and a hydroxyl radical scavenger mannitol. HOCl induced activation of latent HNC was not affected by desferrioxamine and mannitol. Thus, these compounds do not inhibit the active/activated form of HNC. Latent HNC could also be activated by trypsin and chymotrypsin but not by plasmin and plasma kallikrein. The ability of mannitol and desferrioxamine to inhibit the H2O2-induced activation of HNC suggests the transition metal dependent Fenton reaction to be responsible for localized and/or site-specific generation of hydroxyl radical/hydroxyl radical -like oxidants to act as the activating oxygen species. Our results support the ability of myeloperoxidase derived HOCl to act as a direct oxidative activator of HNC and further suggest the existence of a new/alternative oxidative activation pathway of HNC involving hydroxyl radical.
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PMID:Activation of latent human neutrophil collagenase by reactive oxygen species and serine proteases. 217 13

This communication presents four different assay systems for the determination of myeloperoxidase in body fluids. One is based on conventional chemiluminescence, two on luminescence-amplified enzyme measurement using either spiroadamantane-1,2-dioxetanes with alkaline phosphatase or luminol/peroxidase/4-iodophenol coupled with a peroxidase label. The assays covered the range 0-600 micrograms/l peroxidase. Established reference range for EDTA plasma from healthy volunteers gave an upper limit of 250 micrograms/l (95% confidence limits). Intra-assay coefficients of variation were less than 5% for all assays, as seen in compound precision profiles. Inter-assay variation was less than 10% throughout the whole concentration range. Kinetic curves for the light production were performed over a 2 hour period for the enhanced luminescence assays. Dynamic ranges of these assays were compared with the conventional colorimetric assay using 4-nitrophenyl phosphate--alkaline phosphatase. The assay was standardized using a commercially available myeloperoxidase preparation with defined enzymatic activity. The protein content was estimated and the laboratory standard compared and calibrated in mass units.
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PMID:A comparison of four immunometric assays for myeloperoxidase using luminescent and colorimetric signal detection. 217 39


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