5 Lipoxygenase
Mostrando 25-36 de 242 artigos, teses e dissertações.
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25. Growth control of lung cancer by interruption of 5-lipoxygenase-mediated growth factor signaling.
Signal transduction pathways shared by different autocrine growth factors may provide an efficient approach to accomplish clinically significant control of lung cancer growth. In this study, we demonstrate that two autocrine growth factors activate 5-lipoxygenase action of the arachidonic acid metabolic pathway in lung cancer cell lines. Both growth factors
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26. Characterization of human 12-lipoxygenase genes.
Two human 12-lipoxygenase enzyme (arachidonate:oxygen 12-oxidoreductase, EC 1.13.11.31)-related genes were characterized from 13 distinct clones isolated from three genomic bacteriophage and cosmid libraries. A complete gene (12-lipoxygenase gene 1) spanning approximately 17 kilobases and consisting of 14 exons with sequence matching the cloned platelet/huma
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27. Single protein from human leukocytes possesses 5-lipoxygenase and leukotriene A4 synthase activities.
The activity of leukotriene A4 (LTA4) synthase in crude human leukocyte homogenates was found to have a similar requirement for Ca2+ and ATP as had been noted previously for 5-lipoxygenase activity. Purification of the 5-lipoxygenase using ammonium sulfate fractionation, AcA 44 gel-filtration chromatography, and HPLC on anion-exchange and hydroxyapatite colu
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28. Cellular oxidative modification of low density lipoprotein does not require lipoxygenases.
The oxidative modification of low density lipoprotein (LDL) may play an important role in the pathogenesis of atherosclerosis. LDL can be oxidatively modified in vitro by endothelial cells, mouse peritoneal macrophages, or copper ions. Studies using lipoxygenase inhibitors have suggested that lipoxygenase(s) is required for the cellular modification of LDL [
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29. Lymphocytes stimulate expression of 5-lipoxygenase and its activating protein in monocytes in vitro via granulocyte macrophage colony-stimulating factor and interleukin 3.
The aim of this study was to examine the role of lymphocytes in regulating expression of the 5-lipoxygenase pathway in monocytes. When monocytes were cultured over a period of days with lymphocytes, calcium ionophore-stimulated 5-lipoxygenase activity was enhanced. If lymphocytes alone were activated with lectins and their supernatants added to monocytes, st
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30. Inhibition of arachidonate 5-lipoxygenase triggers massive apoptosis in human prostate cancer cells
Diets high in fat are associated with an increased risk of prostate cancer, although the molecular mechanism is still unknown. We have previously reported that arachidonic acid, an omega-6 fatty acid common in the Western diet, stimulates proliferation of prostate cancer cells through production of the 5-lipoxygenase metabolite, 5-HETE (5-hydroxyeicosatetrae
The National Academy of Sciences.
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31. Reversible, calcium-dependent membrane association of human leukocyte 5-lipoxygenase.
Maximal activity of human leukocyte 5-lipoxygenase requires Ca2+, ATP, a microsomal membrane preparation, and two cytosolic stimulatory factors. We report here some effects of Ca2+ on the physical properties of the 5-lipoxygenase. When leukocytes were homogenized in the presence of 2 mM EDTA, 5-lipoxygenase was found to be a soluble enzyme. However, when Ca2
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32. Mutagenesis of some conserved residues in human 5-lipoxygenase: effects on enzyme activity.
Recombinant human 5-lipoxygenase (arachidonate:oxygen 5-oxidoreductase, EC 1.13.11.34) was expressed in Escherichia coli. In incubations of E. coli supernatants with arachidonic acid, 5-hydroxy-7,9,11,14-eicosatetraenoic acid and leukotriene A4 were formed, while incubation with 8,11,14-eicosatrienoic acid gave 8-hydroxy-9,11,14-eicosatrienoic acid. Six cons
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33. On the expression and regulation of 5-lipoxygenase in human lymphocytes.
The expression of arachidonate 5-lipoxygenase (arachidonate:oxygen 5-oxidoreductase, EC 1.13.11.34) and the 5-lipoxygenase-activating protein (FLAP) genes in human tonsillar B cells and lymphoblastoid B-cell lines was demonstrated at the transcriptional level by reverse transcription-PCR analysis. Also, five lymphoblastoid T-cell lines were investigated and
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34. On the nature of the 5-lipoxygenase reaction in human leukocytes: characterization of a membrane-associated stimulatory factor.
When 10,000 X g supernatants of human leukocyte homogenates were subjected to centrifugation at 100,000 X g for 75 min, the activity of 5-lipoxygenase decreased by 30-60%, even though no enzyme was detectable in the resuspended 100,000 X g pellet. Recombination of the 100,000 X g supernatant and pellet resulted in a restoration of the lost enzymatic activity
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35. Enzyme with dual lipoxygenase activities catalyzes leukotriene A4 synthesis from arachidonic acid.
When arachidonic acid was incubated with homogenates of potato tubers, two isomers of 6-trans-leukotriene B4, epimeric at C-12, were formed in addition to the major product, (5S-hydroperoxy-6-trans-8,11,14-cis-icosatetraenoic acid (5-HPETE). To elucidate the mechanism of biosynthesis of the dihydroxy-acids, the lipoxygenase from the potato tubers was purifie
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36. Stimulation of leukotriene biosynthesis in human blood leukocytes by platelet-derived 12-hydroperoxy-icosatetraenoic acid.
Addition of arachidonic acid to suspensions of human blood leukocytes induces the synthesis of small amounts only of the C-5 lipoxygenase products as demonstrated by HPLC. However, the coincubation of blood platelets with the leukocytes always resulted in an activation of the C-5 lipoxygenase and formation of (5S)-5-hydroxy-6,8,11,14-icosatetraenoic acid, (5