Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The membrane-bound flavoprotein NADPH:cytochrome P-450 (cytochrome c) reductase, that functions in electron transfer to cytochrome P-450 monooxygenases, was purified from a cell suspension culture of the higher plant Catharanthus roseus. Anti-serum raised against the purified protein was found to inhibit NADPH:cytochrome c reductase activity as well as the activities of the cytochrome P-450 enzymes geraniol 10-hydroxylase and trans-cinnamate 4-hydroxylase, which are involved in alkaloid biosynthesis and phenylpropanoid biosynthesis, respectively. Immunoscreening of a C. roseus cDNA expression library resulted in the isolation of a partial NADPH: cytochrome P-450 reductase cDNA clone, which was identified on the basis of sequence homology with NADPH:cytochrome P-450 reductases from yeast and animal species. The identify of the cDNA was confirmed by expression in Escherichia coli as a functional protein capable of NADPH-dependent reduction of cytochrome c and neotetrazolium, two in vitro substrates for the reductase. The N-terminal sequence of the reductase, which was not present in the cDNA clone, was determined from a genomic NADPH: cytochrome P-450 reductase clone. It was demonstrated that the reductase probably is encoded by a single copy gene. A sequence comparison of this plant NADPH:cytochrome P-450 reductase with the corresponding enzymes from yeast and animals species showed that functional domains involved in binding of the cofactors FMN, FAD and NADPH are highly conserved between all kingdoms. In C. roseus cell cultures a rapid increase of the reductase steady state mRNA level was observed after the addition of fungal elicitor preparations that are known to induce cytochrome P-450-dependent biosynthetic pathways.
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PMID:Isolation and characterization of a cDNA clone from Catharanthus roseus encoding NADPH:cytochrome P-450 reductase, an enzyme essential for reactions catalysed by cytochrome P-450 mono-oxygenases in plants. 822 Apr 74

The localization of three monooxygenase (hydroxylase) enzyme systems which occur in dark-grown seedlings of Sorghum bicolor has been studied. Cinnamic acid 4-hydroxylase (CAH) (trans-cinnamate 4-monooxygenase, EC 1.14.13.11), which has been increasingly utilized in plants as a marker for the endoplasmic reticulum, migrated with that fraction in continuous and discontinuous sucrose gradients. When 10 mm MgCl(2) was used to shift the density banding of the marker enzyme, NADPH cytochrome c reductase, from 1.12 to 1.17 g/cm(3), the CAH activity was displaced as well.The membrane-bound enzyme system involved in the biosynthesis of the cyanogenic glucoside dhurrin was also shown to be closely associated with the endoplasmic reticulum. This system contains hydroxylases capable of hydroxylating tyrosine to form N-hydroxytyrosine and hydroxylating p-hydroxyphenylacetonitrile to form p-hydroxy-(S)-mandelonitrile.
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PMID:Localization of Cinnamic Acid 4-Monooxygenase and the Membrane-bound Enzyme System for Dhurrin Biosynthesis in Sorghum Seedlings. 1666 Jan 52

The mixed function oxidase trans-cinnamic acid 4-hydroxylase, cytochrome P-450, cytochrome b(5), and NADPH-cytochrome c (P-450) reductase were measured in microsomes from aging artichoke tuber slices exposed to manganese, ethanol, phenobarbital, and the herbicides Chloro-IPC, Dichlobenil, and Monuron. Although the microsomal hydroxylating complex is already induced by the slicing and aging process, 25 millimolar MnCl(2), 4 millimolar phenobarbital, and 300 millimolar ethanol caused a marked increase of hydroxylase activity and cytochrome P-450 content and shifted their time course. The herbicides, 200 micromolar Dichlobenil and 200 micromolar Monuron, were less effective. Chloro-IPC was slightly inhibitory. NADPH cytochrome c reductase was significantly increased only in phenobarbital-treated slices. Cytochrome b(5) was generally the least affected among the parameters being measured. The mechanisms by which these compounds increase cytochrome P-450 content and hydroxylase activity are not yet defined.
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PMID:Time Course of Induction of Cytochrome P-450, NADPH-Cytochrome c Reductase, and Cinnamic Acid Hydroxylase by Phenobarbital, Ethanol, Herbicides, and Manganese in Higher Plant Microsomes. 1666 86