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Hydroperoxidases

HYDROPEROXIDASES USE HYDROGEN PEROXIDE OR AN ORGANIC PEROXIDE AS SUBSTRATE... [Pg.88]

Hydroperoxidases protect the body against harmful peroxides. Accumulation of peroxides can lead to generation of free radicals, which in turn can dismpt membranes and perhaps cause cancer and atherosclerosis. (See Chapters 14 and 45.)... [Pg.88]

Oxidoreductases have a variety of functions in metabolism oxidases and dehydrogenases play major roles in respiration hydroperoxidases protect the body against damage by free radicals and oxygenases mediate the hydroxylation of drugs and steroids. [Pg.91]

Nunez-Delicado E, Sojo MM, Sanchez-Ferrer A and Garcia-Carmona F. 1999. Hydroperoxidase activity of lipoxygenase in the presence of cyclodextrins. Arch Biochem Biophys 367(2) 274-280. [Pg.128]

These observations suggest that vitamin E may play a regulatory role in PG biosynthesis by controlling the formation of key intermediates such as hydroperoxides and cyclic endoperoxides. In these experiments, peroxidase activity associated with the PGH synthase could not be measured because of the contamination of other peroxidases like cyt P-450 hydroperoxidase in crude microsomal preparations. Our attempts to measure the differences in catalytic rates employing indomethacin were not successful. Nevertheless, it is not too unreasonable to assume that probably both activities of PGH synthase are equally affected by vitamin E deficiency, since both require heme as cofactor. [Pg.262]

Figure 16.24 Major prostaglandin and leukotriene products derived from arachidonic acid via the cyclooxygenase and 5-lipooxygenase pathways. Major enzymes 1, cyclooxygenase 2, hydroperoxidase 1 + 2, prostaglandin endoperoxidase synthetase 3, thromboxane synthetase 4, prostacyclin synthetase 5, 5-lipooxygenase 6, 9-ketoisomerase 7, PGH-PGF2a reductase 8, 11-ketoisomerase 9, PGE reductase 10, PGD reductase. (Reproduced by permission from Nelson NA, Kelly RC, Johnson, RA. Prostaglandins and the arachidonic acid cascade. Chem Eng News August 30-44, 1982.)... Figure 16.24 Major prostaglandin and leukotriene products derived from arachidonic acid via the cyclooxygenase and 5-lipooxygenase pathways. Major enzymes 1, cyclooxygenase 2, hydroperoxidase 1 + 2, prostaglandin endoperoxidase synthetase 3, thromboxane synthetase 4, prostacyclin synthetase 5, 5-lipooxygenase 6, 9-ketoisomerase 7, PGH-PGF2a reductase 8, 11-ketoisomerase 9, PGE reductase 10, PGD reductase. (Reproduced by permission from Nelson NA, Kelly RC, Johnson, RA. Prostaglandins and the arachidonic acid cascade. Chem Eng News August 30-44, 1982.)...
Regelsberger G, Jakopitsch C, Plasser L et al (2002) Occurrence and biochemistry of hydroperoxidases in oxygenic photorophic prokaryotes (cyanobacteria). Plant Physiol Biochem 40 479 190... [Pg.32]

Klotz M, Loewen PC (2003) The molecular evolution of catalatic hydroperoxidases evidence for multiple lateral transfer of genes between prokaryota and form bacteria into eukaryota. Mol Biol Evol 20 1098-1112... [Pg.32]

Another pathway is the fatty acid hydroperoxidase lyase (HPL) pathway. This pathway produces C6-aldehydes and C12-oxo acids. 2 C6-volatiles, including ( )-2-hexenal, (Z)-3-hexenal, hexanal, as well as their corresponding alcohols or esters, are produced from mechanically wounded plant tissue.197,203 C6-aldehydes are also formed during hypersensitive response to infection by bacterial pathogens, after insect feeding, and after exogenous application ofJA.204,205 As already shown in this chapter, some of C6-volatiles are known to be attractants of parasitoids and predators. [Pg.359]

A quarter of a century has passed since the first contribution on catalase to The Enzymes Enzyme substrate compounds Mechanism of action of hydroperoxidases (I). In this perspective, we can identify a sequence of steps in the development of ideas on the mechanism of enzymic action and the nature of enzyme-substrate compounds. The identification of these compounds and the approach to enzymic reactions at concentrations stoichiometric with the substrate caused a principal transition of viewpoint on hemoprotein catalysis from free radical mechanisms (2) unrelated to an active center toward the acceptance of catalysis occurring at the iron atom of the porphyrin (S-5). The latter concept followed natu-... [Pg.363]

Generation of aldehydes is discussed to be achieved by action of lyases and hydroperoxidases [198,217,218] epoxygenases are claimed to transfer IffODEs to epoxy hydroxy fatty acids [217,219] which are... [Pg.77]

Figure 5 Conversion of acetaminophen to its reactive free radical by co-oxidation mediated by the hydroperoxidase activity of prostaglandin H synthase-catalyzed reduction of prostaglandin Ga (PGGa) to prostaglandin Ha (PGHa). Figure 5 Conversion of acetaminophen to its reactive free radical by co-oxidation mediated by the hydroperoxidase activity of prostaglandin H synthase-catalyzed reduction of prostaglandin Ga (PGGa) to prostaglandin Ha (PGHa).

See other pages where Hydroperoxidases is mentioned: [Pg.151]    [Pg.831]    [Pg.86]    [Pg.233]    [Pg.149]    [Pg.151]    [Pg.364]    [Pg.1121]    [Pg.105]    [Pg.121]    [Pg.930]    [Pg.349]    [Pg.56]    [Pg.930]    [Pg.59]    [Pg.706]    [Pg.739]    [Pg.261]    [Pg.203]    [Pg.8]    [Pg.8]    [Pg.188]    [Pg.721]    [Pg.163]    [Pg.364]    [Pg.1951]    [Pg.381]    [Pg.935]    [Pg.706]    [Pg.303]    [Pg.303]    [Pg.1487]   
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See also in sourсe #XX -- [ Pg.184 , Pg.196 , Pg.197 , Pg.198 , Pg.199 , Pg.200 , Pg.201 , Pg.202 , Pg.203 , Pg.204 , Pg.205 , Pg.207 ]

See also in sourсe #XX -- [ Pg.120 , Pg.164 ]

See also in sourсe #XX -- [ Pg.359 ]




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