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)

7,12-Dimethylbenz(a)anthracene-induced rat mammary tumors often contain high levels of the enzyme perioxidase, a putative marker of estrogen dependence. This enzyme can be effectively extracted with 0.5 M CaCl2, giving rise to a soluble peroxidase with a molecular weight of about 50,000 as determined by gel filtration. This is the same size as the estrogen-induced peroxidase of rat uterus but smaller than other mammalian peroxidases. Further purification of the rat mammary tumor peroxidase by concanavalin A-Sepharose chromatography and hydrophobic interaction chromatography on phenyl Sepharose provides a 640-fold purification of the enzyme.
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PMID:Isolation and purification of rat mammary tumor peroxidase. 10 Feb 15

Hydrogen peroxide-dependent oxidation of xenobiotics in a crude fraction of human term placental membranes (nuclei, mitochondria and microsomes) was investigated. Guaiacol was employed as a model substrate. The rate of its oxidation was found to be dependent on the concentration of protein, H2O2 and the substrate as well as the pH of the buffer. Several other classical substrates for peroxidases from different sources viz. pyrogallol, benzidine, p-PDA, DMBD, ABTS, TMPD and TMBD and endogenous chemicals such as bilirubin and epinephrine were also found to undergo oxidation. The xenobiotic oxidizing capacity of the membranes was retained by CaCl2 (0.5 M) extract as well as by the partially purified enzyme obtained by affinity (Con A) chromatography. The H2O2-dependent chemical oxidation by the partially purified peroxidase was inhibited by NaN3 and KCN (IC50 values 41 and 23 microM respectively). These results suggest that peroxidase may be a major enzyme in human term placenta capable of oxidation of endogenous chemicals and xenobiotics.
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PMID:Peroxidase: a novel pathway for chemical oxidation in human term placenta. 129 5

In a cathodal polyacrylamide gel electrophoresis system, three distinct groups of isoperoxidases from Lupinus albus were found to achieve retention factors (rf) dependent on the quantity of sample applied onto the gel. The possibility of extract-derived substances weakly associating with peroxidase samples was investigated. Association of the putative agents survived dialysis against electrophoresis buffer with and without 2 M CaCl2 and freeze-thaw treatments. The addition of polyvinylpolypyrrolidone and polyethylene glycol to the homogenization buffer also proved ineffective in eliminating the variation in isoperoxidase rf although differences in the zymogram profiles of these samples were evident. The addition of spermine and cytochrome c to samples was found to increase the rf of some peroxidase bands. Electrophoresis of samples with cytochrome c resulted in the resolution of peroxidase groups to distinct bands at rf independent of the quantity of peroxidase applied. Control experiments indicate that this treatment did not introduce any detectable artifacts.
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PMID:Cytochrome c aided resolution of Lupinus albus isoperoxidases in a cathodal polyacrylamide gel electrophoresis system. 131 83

The objective of this study was to develop a simplified method for the simultaneous analysis of cellular karyotype and phenotype which would permit the identification of cell origin. We studied 6 patients with AML, 3 with CML (one of which was in blastic transformation) and one ALL. We used a method in which the suspension of bone marrow cells was incubated in TC 199 medium with colchicine and with hypotonic solution formed from glycerol, NaCl, KCl, CaCl2, MgCl2 and sucrose. The slides were prepared from this cell suspension by cytospin and stained for peroxidase, PAS, esterases and iron. The karyotype was studied by direct method and culture. It was possible to relate the cytogenetic marker with cytochemistry characteristics in the same cell in 3 cases, showing the feasibility of cytochemistry techniques in cytogenetical preparations. The best preparations were found through peroxidase. The presence of iron granules allowed identification of erythroblastic lineage in the combined staining. Mitosis with a marker chromosome of leukemic clone in an AML cell with negative peroxidase probably showed a proliferation of more primitive precursor not sufficiently differentiated to show markers.
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PMID:Simplified method for the analysis of cellular karyotype and phenotype in leukemias. 134 Oct 1

The monoclonal antibody NMC-VIII/10 is a neutralizing antibody which recognizes the Glu1675-Glu1684 sequence of the factor VIII light chain and inhibits factor VIII (FVIII) binding to immobilized von Willebrand factor (vWf). In this study we immunohistochemically determined, using human umbilical cord tissue, whether or not NMC-VIII/10 has an inhibitory effect on FVIII binding to endogenous vWF in endothelial cells. Tissue sections were reacted with purified FVIII followed by peroxidase-conjugated monoclonal antibody (C5) recognizing the 54 kD fragment of the FVIII heavy chain. The labelling pattern of bound FVIII was similar to that of endogenous vWF and appeared as a fine granular deposit in the endothelial cells. Addition of purified vWF completely inhibited the binding of FVIII to endothelial cells. Furthermore, FVIII did not bind to endothelium in the presence of 0.25 M CaCl2, and similarly, thrombin-treated FVIII did not bind to the vascular site. These findings suggested that FVIII was bound to endogenous vWF in the endothelial cells. The binding reaction was completely inhibited by NMC-VIII/10, confirming that the monoclonal antibody recognizes the specific epitope responsible for FVIII binding to endogenous vWF.
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PMID:A monoclonal antibody (NMC-VIII/10) to factor VIII light chain recognizing Glu1675-Glu1684 inhibits factor VIII binding to endogenous von Willebrand factor in human umbilical vein endothelial cells. 139 Feb 41

In order to prepare biosensing electrodes which respond to hydrogen peroxide, horseradish peroxidase has been adsorbed to colloidal gold sols and electrodes prepared by deposition of these enzyme-gold sols onto glassy carbon using three methods: evaporation, electrodeposition and electrolyte deposition. In the latter method the enzyme-gold sol is applied to the surface of a glassy carbon disk electrode followed by an equal volume of 2 mM CaCl2. The electrolyte causes the sol to precipitate on the electrode surface, producing an immobilized enzyme electrode. Satisfactory electrodes which gave an electrochemical response to hydrogen peroxide in the presence of the electron transfer mediator ferrocenecarboxylic acid were produced by all three methods. Evaporation of horseradish peroxidase-gold sols produced electrodes with the best reproducibility and the widest linear amperometric response range. These electrodes can also easily be stored in a dry state. Although not as good as evaporation, electrodeposition also produced satisfactory electrodes. Electro-deposition provides the added advantage that it lends itself to the preparation of multi-enzyme/multi-analyte electrodes by the adsorption of different enzymes to separate gold sols, followed by sequential electrodeposition onto discrete areas of a multichannel electrode.
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PMID:Comparison of colloidal gold electrode fabrication methods: the preparation of a horseradish peroxidase enzyme electrode. 151 18

Peroxidase activity in the uterine luminal fluid of mice treated with diethylstilbestrol was measured by the guaiacol assay and also by the formation of 3H2O from [2-3H]estradiol. In the radiometric assay, the generation of 3H2O and 3H-labeled water-soluble products was dependent on H2O2 (25 to 100 microM), with higher concentrations being inhibitory. Tyrosine or 2,4-dichlorophenol strongly enhanced the reaction catalyzed either by the luminal fluid peroxidase or the enzyme in the CaCl2 extract of the uterus, but decreased the formation of 3H2O from [2-3H]estradiol by lactoperoxidase in the presence of H2O2 (80 microM). NADPH, ascorbate, and cytochrome c inhibited both luminal fluid and uterine tissue peroxidase activity to the same extent, while superoxide dismutase showed a marginal activating effect. Lactoferrin, a major protein component of uterine luminal fluid, was shown not to contribute to its peroxidative activity, and such an effect by prostaglandin synthase was also ruled out. However, it was not possible to exclude eosinophil peroxidase, brought to the uterus after estrogen stimulation, as being the source of peroxidase activity in uterine luminal fluid.
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PMID:Characteristics of estrogen-induced peroxidase in mouse uterine luminal fluid. 165 74

Peroxidases can metabolize a variety of xenobiotics to reactive intermediates capable of binding to protein or DNA. The potential role of these enzymes in fetotoxicity has not been explored. In this study, the presence of peroxidase activity was observed in human term and pre-term placenta. Human term placental peroxidase activity (HTPP) was partially purified by concanavalin A affinity chromatography from CaCl2 extracts of the particulate fraction. HTPP appears to be a membrane-bound glycoprotein. Arachidonic acid-dependent oxidation of guaiacol was not observed, suggesting that the peroxidase activity was not due to prostaglandin synthase. Moreover, HTPP preparations were devoid of catalase and spectrally dissimilar from human haemoglobin, cytochrome P-450, eosinophil peroxidase and myloperoxidase, suggesting an endogenous origin. An Mr of approx. 119,000 was determined for HTPP by gel filtration. Cathodic slab-PAGE of cetyltrialkylammonium bromide-solubilized HTPP yielded two peroxidase-staining bands.
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PMID:Partial purification and characterization of a peroxidase activity from human placenta. 236 7

Frog esophageal mucosa contains peptic glands which are innervated by cholinergic neurons. When incubated in a medium containing 1.5 mM CaCl2, pepsinogen release from esophageal mucosa was increased by a high potassium concentration (55 mM KCl), 1,1-dimethyl-4-phenylpiperazinium (DMPP) or bethanechol. Whereas the response to bethanechol remained little changed, the response to high KCl concentrations or DMPP was abolished in the absence of Ca2+. The stimulatory effects of high KCl concentrations and DMPP were also eliminated by the presence of atropine or somatostatin. Furthermore, pepsinogen release in response to bethanechol was dose-dependently inhibited by somatostatin. Frog esophagus was found to contain somatostatin-like immunoreactivity, with a higher density at the end adjacent to the stomach. Chromatography of mucosa extract on Sephadex G-50 revealed a single peak of somatostatin-like immunoreactivity that coeluted with somatostatin-14. Immunohistochemical staining of the mucosa with peroxidase antiperoxidase technique demonstrated the presence of two varieties of somatostatin-like immunoreactivity-containing cells, one individually dispersed within the intercalated septa and the other in groups within the interlobular septa of the peptic glands. These results seem to indicate that somatostatin or somatostatin-like immunoreactivity may play a modulatory role in neurally mediated pepsinogen secretion in the frog esophagus.
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PMID:Somatostatin modulation of neurally mediated pepsinogen secretion from frog esophageal mucosa. 289 27

Thirty-one normal women were studied daily in 41 cycles. Venous blood samples were taken for measurements of luteinizing hormone (LH), estradiol (E2), and progesterone (P), and vaginal examinations were done to obtain cervical mucus and vaginal fluid. The specific activity of guaiacol peroxidase (GP), extracted from cervicovaginal secretions with 0.5 M CaCl2, was determined in the vaginal samples. In the follicular phase, from day -7 to day 0 (the LH +1 day, when ovulation presumably occurred), there was a strong negative correlation between GP and the rising E2 (r = -0.94). On days 1 to 10 after ovulation, there was a strong positive correlation between GP and P (r = 0.84). In nine ovulatory cycles in which P levels did not exceed 8 ng/ml on any day, indicating possible luteal phase inadequacy, there were significantly lower GP levels than in another 32 ovulatory cycles with higher P (P = 0.04). These results suggest that (1) at midcycle, E2 seems to "down-regulate" the GP specific activity; and (2) in the luteal phase, serum P levels parallel those of GP activity, even in the presence of high luteal E2. GP activity profiles during the menstrual cycle can be used to define the fertile period, may prove useful in diagnosing pregnancy, and may be a simple, convenient test for an inadequate corpus luteum.
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PMID:Cervicovaginal peroxidases: sex hormone control and potential clinical uses. 299 Oct 22


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