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)

Adriamycin (ADR) failed to inhibit and paradoxically enhanced the biological action of 12-O-tetradecanoylphorbol-13-acetate (TPA) in mouse epidermis in vivo and in vitro. In the presence of ADR, the tumor promoter caused a greater sequential rapid increase and prolonged decrease in glutathione (GSH) peroxidase (GSH:H2O2 oxidoreductase, EC 1.11.1.9) activity accompanied by a greater decrease in the ratio of reduced (GSH)/oxidized (GSSG) glutathione in isolated epidermal cells. The ability of ADR to deplete the intracellular level of GSH correlated with its ability to increase basal and TPA-induced ornithine decarboxylase (ODC, L-ornithine carboxylase, EC 4.1.1.17) activities. In vivo, topical ADR treatments also enhanced TPA-induced ODC activity as well as the tumor-promoting ability of TPA in the two-stage system of mouse skin carcinogenesis. Since lipid peroxidation has been associated with ADR toxicity, these data suggest that the enhancement of the tumor-promoting ability of TPA by ADR may be the result of an increased oxidative challenge that overwhelms the GSH-dependent antioxidant protective system of the epidermal cells.
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PMID:Enhancement by adriamycin of the effects of 12-O-tetradecanoylphorbol-13-acetate on mouse epidermal glutathione peroxidase activity, ornithine decarboxylase induction and skin tumor promotion. 407 83

There is growing evidence that natural killer (NK) cells play an important role in immune surveillance against tumors and certain infections. The coexistence of activated neutrophils with lymphocytes in tumor masses and inflammatory tissues suggests the possibility of interaction between secreted neutrophil products and nearby lymphocytes. We examined the susceptibility of lymphocyte NK activity to oxidative injury by the neutrophil myeloperoxidase (MPO) system and H2O2 with the use of a cellfree model system. Exposure of human mononuclear leukocytes (MNL) to MPO, an H2O2-generating system (glucose + glucose oxidase), and a halide (C1- or I-) resulted in marked suppression of MNL-NK activity, as measured by 51Cr release from K562 tumor targets (p less than 0.001). This suppression was dependent on the presence and activity of each system component and was blocked by azide and catalase, but not by heated catalase. In spite of the marked functional suppression of NK activity, MNL viability was more than 95% and target binding frequency was not affected. NK suppression was reversible after 24 hr in culture. The mechanism of suppression was dependent on the amount and rate of H2O2 delivered, and on MNL number. MPO was essential when H2O2 flux was low or when MNL numbers were high. As H2O2 flux increased or MNL numbers decreased, NK suppression gradually became MPO-independent and was mediated by H2O2 alone. The ability of the MPO system to compromise lymphocyte NK function may explain the in vitro inhibition of NK activity of mixed cell populations by the tumor promoter phorbol esters, because these agents are potent stimulants for neutrophil secretion of MPO and H2O2. This study may also provide a possible mechanism for the reported in situ NK activity suppression by adherent phagocytic cells during carcinogenesis in both humans and animals.
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PMID:Down-regulation of human natural killer activity against tumors by the neutrophil myeloperoxidase system and hydrogen peroxide. 609 70

Preneoplastic liver foci were produced in female Wistar rats by the administration of 2-acetylaminofluorene (0.03% w/w) in the diet for 174 days. Increased UDP-glucuronyltransferase (UDP-GT) could be visualized immunohistochemically in the same focal areas which were ATPase-negative and gamma-glutamyltranspeptidase-positive. Immunohistochemical detection was possible using rabbit anti-UDP-GT and peroxidase-labeled swine anti-rabbit immunoglobulins. The results of immunohistochemistry were substantiated by enzyme determination in microdissected material. UDP-GT activity was 5-fold higher in focal areas in comparison with the surrounding liver tissue. Increased UDP-GT activity in conjunction with the altered pattern of other drug-metabolizing enzymes is consistent with increased resistance of preneoplastic cells to the cytotoxicity of carcinogens. Immunohistochemical detection of UDP-GT may provide a new marker for preneoplastic lesions which, in conjunction with other markers, may prove useful in analyzing the various stages of liver carcinogenesis and the remodeling of preneoplastic lesions after cessation of carcinogenic stimuli.
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PMID:Immunohistochemical and biochemical detection of uridine-diphosphate-glucuronyltransferase (UDP-GT) activity in putative preneoplastic liver foci. 613 91

A method is proposed for the simultaneous staining of neutral and acidic, periodate reactive and nonperiodate reactive mucosubstances, glycogen and keratin in paraffin sections. Briefly, sections are stained by the Alcian blue (pH 2.5)-PAS method, followed by a peroxidase-antiperoxidase immunohistochemical stain for keratin. The proposed method modifies an existing method, and expands the range of polysaccharides and mucosubstances which may be demonstrated. The proposed method is easily performed within a single working day and promises to be of value in surgical pathology as well as in studies of bronchial carcinogenesis.
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PMID:An Alcian blue (pH 2.5)-PAS-keratin immunoperoxidase method for the simultaneous demonstration of keratin and neutral and acidic mucosubstances. 619 75

12-)-Tetradecanoylphorbol-13-acetate (TPA), the prototype polyfunctional diterpene ester tumor promoter of two-step carcinogenesis in mouse skin, induced differentiation of human promyelocytic leukemia cells (HL-60) in culture. Differentiation of HL-60 cells was characterized by increased phagocytosis, increased lysozyme activity (EC 3.2.1.17) in the growth medium, and changes in morphology to those characteristics of more mature cells resembling macrophages. Many of the cells treated with TPA became aggregated, attaching firmly to culture flasks. The average intracellular myeloperoxidase activity (EC 1.11.1.7) per cell decreased during induction of differentiation by TPA. It was also found that TPA enhanced, rather than inhibited, differentiation of HL-60 cells induced by DMSO. In addition to TPA, several polyfunctional diterpene esters of the tigliane, ingenane, and daphnane type have been tested for their ability to induce morphological and functional changes of HL-60 cells. The activities of the compounds to induce these changes correlated well with their activities as tumor promoters in two-step carcinogenesis in mouse skin. In particular, half the concentrations required for induction of adhesion of the cells to flasks were roughly correlated to the potency of these compounds as tumor promoters. Among the compounds tested, phorbol-12,13-didecanoate (PDD), ingenol-3-hexadecanoate, Pimelea factor P1 and Pimelea factor P2 were as active as TPA, while 4-O-methyl-TPA and 4 alpha-PDD were much less active. Phorbol and ingenol were totally inactive up to a concentrations 10,000-fold higher than that of TPA.
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PMID:Induction of differentiation in human promyelocytic leukemia cells by tumor promoters. 628 Dec 83

Prostaglandin H synthase (PHS) and horseradish peroxidase catalyze the oxidation of benzidine to the same free radical species. No radical was observed if either benzidine, H2O2 or enzyme was omitted. The similarity of the fine structure of this radical to a computer-simulated model suggests the presence of a free cation radical of benzidine. Neither superoxide nor hydroxyl radicals appear to be involved in the co-oxidation of benzidine or 2-amino-4-(5-nitro-2-furyl)-thiazole (ANFT) by PHS. Production of the benzidine radical by PHS was inhibited by ANFT, acetaminophen, cyanide and ascorbate. ANFT was metabolized by PHS but not by horseradish peroxidase. ANFT had no effect on either radical production or 14C-metabolism of benzidine by horseradish peroxidase. These results indicate that different peroxidases may exhibit specificity with respect to the carcinogens they activate. The free radical cation of benzidine may be the electrophilic intermediate responsible for PHS-catalyzed binding of benzidine to protein and nucleic acids.
Carcinogenesis 1983
PMID:Prostaglandin H synthase metabolism of the urinary bladder carcinogens benzidine and ANFT. 629 1

The oxidation of carcinogenic hydroxamic acids, N-hydroxy-N-2-fluorenylacetamide (N-OH-2-FAA) and N-hydroxy-N-3-fluorenylacetamide (N-OH-3-FAA) catalyzed by horseradish peroxidase (HRP) or cytochrome c in the presence of H2O2 was investigated. HRP/H2O2 was a more efficient system in oxidation of both hydroxamic acids and the standard substrate, guaiacol, then cytochrome c/H2O2. Peroxidative activity of cytochrome c was shown after incubation with Triton X-100 and H2O2 for 20 min at room temperature in 0.05 M phosphate buffer (pH 7.5) or in 0.1 M sodium acetate (pH 6.0) without Triton X-100. Both hydroxamic acids were oxidized to nitroxyl free radicals as shown by electron spin resonance (ESR) spectroscopy. These radicals dismutated to equimolar amounts of 2- or 3-nitrosofluorene and acetate esters of the corresponding hydroxamic acids as shown by thin layer chromatography and spectrophotometric analysis of the products. In addition, large amounts of the N-fluorenylamides were generated in the reactions with cytochrome c/H2O2 system. Of the products, only 2- or 3-nitrosofluorene per se or when generated from the oxidation of the hydroxamic acids, interacted with lecithin (1 mg/ml) to yield ESR signals of the immobilized nitroxyl free radicals. In contrast to HRP/H2O2 system, in which the initial velocity of the radical formation was too fast to measure and the maximal concentrations of the nitroxyl free radicals of both hydroxamic acids were similar, in the cytochrome c/H2O2 system the nitroxyl free radical of N-OH-2-FAA formed at a 6-fold faster rate and accumulated at a 2-fold higher concentration than the radical of N-OH-3-FAA. In both enzyme systems, the persistence of the signal and the length of time before it had decreased to one half its maximum were several-fold longer for the nitroxyl free radical of N-OH-3-FAA than for that of N-OH-2-FAA. These data showed that these nitroxyl free radicals differed in their kinetic properties. One electron oxidation of N-OH-3-FAA by HRP/H2O2 system and of both isomeric hydroxamic acids by cytochrome c/H2O2 system are reported for the first time in this work and may be considered an activation reaction in carcinogenesis by these compounds.
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PMID:Cytochrome c/H2O2-mediated one electron oxidation of carcinogenic N-fluorenylacetohydroxamic acids to nitroxyl free radicals. 631 47

Variation of the binding Ulex europaeus agglutinin-I (Ulex-I), a lectin specific for blood group H(O) substance, was examined in normal, dysplastic and cancerous esophageal epithelium from 43 instances of carcinoma by means of the lectin- antilectin peroxidase-antiperoxidase method. The normal epithelium showed strong staining at the cell border, although the basal cells were entirely negative. In mild and moderate dysplasia, staining was negative, while in some cases of severe dysplasia positive staining was found in the basal cells. Most of the basal cells in carcinoma in situ revealed granular or diffuse positive staining in the cytoplasm. The results indicate that the loss of blood group H antigen occurs during carcinogenesis of the esophageal mucosa. Thus, Ulex-I may be a useful marker of cytoplasmic differentiation of the esophagus.
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PMID:Blood group H(O) antigen in normal, dysplastic and carcinomatous esophageal epithelium. 637 74

The prostaglandin synthase and horseradish peroxidase catalyzed binding of p-phenetidine to DNA was investigated. The addition of arachidonic acid to an incubation containing ram seminal vesicle microsomes, [14C]p-phenetidine and DNA resulted in a rapid incorporation of radioactivity into DNA. This was inhibited by greater than 75% by indomethacin (0.1 mM) or butylated hydroxyanisole (0.5 mM). Hydrogen peroxide was as efficient as arachidonic acid in mediating the activation of p-phenetidine thus implicating the involvement of the hydroperoxidase activity of prostaglandin synthase in this reaction. Horseradish peroxidase and hydrogen peroxide also catalyzed the activation of p-phenetidine to DNA-binding metabolites. Reduced glutathione (GSH) stimulated the binding of p-phenetidine to DNA by greater than 3-fold in both the prostaglandin synthase and the horseradish peroxidase system, whereas cysteine and N-acetylcysteine reduced the DNA-binding in the prostaglandin synthase system by up to 62% under the conditions used. Furthermore, water-soluble metabolites formed in the presence of GSH also bound to DNA. Seventy-two hour dialysis of DNA samples from incubations with GSH present reduced the amount of bound material by 75%. In contrast, the radioactivity which associated with DNA in the absence of GSH was not decreased by dialysis.
Carcinogenesis 1984 Feb
PMID:Prostaglandin synthase and horseradish peroxidase catalyzed DNA-binding of p-phenetidine. 642 1

The lectin, Concanavalin A(Con A) has been used to localize specific sugar residues (D-glucose, D-mannose and D-fructose) in premalignant lesions and squamous-cell carcinomas induced following cryosurgery of the mouse submandibular gland. The original Con A-horseradish peroxidase (HRP) technique as well as its combination with periodate oxidation and subsequent reduction by borohydrate were used to compare the epithelial elements during submandibular gland carcinogenesis. Granules in the granular convoluted tubule cells which were weakly reactive to the Con A-HRP method were not present in the premalignant duct like structures. The epithelium of premalignant lesions, duct-like structures, multicystic lesions, and squamous-cell carcinomas were positive for the cell-surface and intercellular substances; and basement membranes and stromal fibers were also positive. The results indicated that throughout malignant transformation of the ductal segments, premalignant epithelia lost Con A-HRP-staining granules and that Con A-binding patterns in induced squamous-cell carcinomas were similar to those found in squamous-cell epithelium.
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PMID:Histochemical studies on Concanavalin A-binding in experimental carcinoma of the mouse submandibular gland. 643 86


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