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)

A new procedure for the isolation of membrane vesicles from Acholeplasma laidlawii cells is described. The membrane vesicles are completely free from contaminations of whole cells and cell debris and represent a homogeneous fraction as shown by electron microscopy, Ficoll density-gradient centrifugation, and titration on agar plate. Absence of cytoplasmic contaminations was confirmed by double-labelling of membranes with 3H-oleic acid and 14C-uridine, as well as by distribution of specific marker enzymes of membranes and cytoplasm. On the basis of light-scattering and electron microscopy, the vesicular nature of these membranes was established. The vesicles had the same orientation as intact cells (absence on membrane vesicles of ATPase and NADH dehydrogenase activities, localized in the inner surface of membrane). The respiratory activity of the membrane vesicles was low and was not stimulated by exogenous substrates, the respiratory chain of the vesicles being reduced and terminated by flavoproteins. The ability of membrane vesicles to take up carbohydrates was shown.
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PMID:Transport properties of membrane vesicles from Acholeplasma laidlawii. I. Isolation and general characteristics. 12 39

In the cells of RH, SPEV and HEp-2 lines irradiated with 6.5 mm radiowaves of 1 mW/cm2 flux density the following phenomena were established: activation of succinate dehydrogenase and ATPase; reduction of cytochrome oxidase, NAD- and NADP-diaphorase, acid and alkaline phosphatase activities; repression of 3H-thymidine incorporation in DNA and of 3H-uridine incorporation in RNA; violation of ultrastructure; suppression of cellular proliferation; decrease of mitotic activity; occurrence of pathological forms of mitosis.
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PMID:[Biological oxidation in cells exposed to microwaves in the millimeter range]. 68 31

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49

With the aid of cDNA and RNA sequence analysis, we have determined to what extent transcripts of mitochondrial maxicircle genes of the insect trypanosome Crithidia fasciculata are altered by RNA editing, a novel mechanism of gene expression which operates via the insertion and deletion of uridine residues. Editing of cytochrome c oxidase (cox) subunit II and III transcripts and of maxicircle unidentified reading frame (MURF) 2 RNA is limited to a small section and results in the creation of a potential AUG translational initiation codon (coxIII, MURF2) or the removal of a frameshift (coxII). No differences with the genomic sequences were observed in the remainder of these RNAs. Surprisingly, NADH dehydrogenase subunit I transcripts were completely unedited in the coding region, implying that an AUG translational initiation codon is absent. The partial ribosomal RNA sequences determined also conform to the gene sequences. Together these results lead to the conclusion that the unusual sequences predicted by the protein and rRNA genes must indeed be present in the gene products. Editing also occurred in the poly(A) tail of RNAs from all protein genes, including those that are unedited in the coding region. The tails display a large variation in AU sequence motifs. Finally, some cDNAs contained sequences absent from both the DNA and the edited RNA. Some of these may represent intermediates in the RNA editing process. We argue, however, that long runs of T may be artefacts of cDNA synthesis.
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PMID:RNA editing in transcripts of the mitochondrial genes of the insect trypanosome Crithidia fasciculata. 168 30

Chimeric RNA molecules were detected by polymerase chain reaction amplification of kinetoplast RNA using a 3' primer specific to mRNA and a 5' primer specific to guide RNA (gRNA), and directly by Northern analysis. Covalent linkage of the 3' oligo(U) tail of the gRNA to the mRNA occurs at editing sites. Chimeric molecules were isolated for NADH dehydrogenase subunit 7 and cytochrome oxidase subunits II and III. We propose that these molecules are intermediates in the editing process and that successive transesterifications result in the transfer of uridine residues from the gRNA 3' oligo(U) tail to an editing site, with the number of uridine residues determined by base pairing with adenine and guanine "guide" nucleotides in the gRNA.
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PMID:Chimeric gRNA-mRNA molecules with oligo(U) tails covalently linked at sites of RNA editing suggest that U addition occurs by transesterification. 170 91

We describe an assay for light microscopic visualization of specific glycosyltransferases on tissue sections or on cells. The assay uses a sequence of enzyme reactions that yields two moles of NADH for each mole of the uridine-5'-diphosphate (UDP) released during transfer of a monosaccharide from a UDP sugar to an acceptor. When diaphorase and tetrazolium salts are present in the incubation mixture, the tetrazolium salts are reduced to colored diformazans, which precipitate at the sites of glycosyltransferase activity. The validity of the assay was established by applying the technique to spermatozoa and liver, in which some glycosyltransferases have previously been localized. When suspensions of mouse spermatozoa were assayed for galactosyltransferase (GalTase) activity, diformazan precipitates appeared on the plasma membranes overlying the anterior heads of the spermatozoa, in agreement with immunochemical localizations. In mouse liver slices assayed with bilirubin as acceptor for glucuronyltransferase (GluTase) activity, dense diformazan deposits appeared on the hepatocytes but not on endothelial cells, also in agreement with immunochemical data. In the absence of acceptor or UDP sugar donor, diformazan deposits were minimal and random in all tissues tested. The assay's versatility was tested by incubating tissues with different sugar donors and acceptors to localize other sites of transferase activity. In mouse frozen liver sections, GalTase activity occurred in both hepatocytes and endothelial cells; in sections of rat submaxillary glands, GalTase activity was detected in mast cells. In liver sections, GlcuTase activity with o-aminophenol as acceptor was located primarily on the endothelial cells. With the appropriate sugar donor and acceptor, this assay should detect any transferase, other than the glucosyltransferases, that utilizes UDP sugars.
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PMID:Light microscopic localization of glycosyltransferase activities in cells and tissues. 210 33

Diets containing 12 or 48% of calories from corn oil were fed to weanling Sprague-Dawley female rats for 28 days. Hepatic cytochrome P-450 content was higher with the high-fat diet, but the activities of cytochrome P-450 reductase, cytochrome c reductase, benzo[a]pyrene hydroxylase (BPH), and uridine-5'-diphosphoglucuronic acid (UDPGA) transferase were unchanged. There were no differences in small intestinal cytochrome P-450 or BPH attributable to diet. Additional rats given an oral dose of 14C-7,12-dimethylbenz[a]anthracene (14C-DMBA) after 28 days of feeding showed no effects of diet on the cumulative daily excretion of radioactivity from 14C-DMBA in the urine or feces over 72 h. However, rats fed the high-fat diet showed greater concentrations of radioactivity in the liver, kidney, adrenal, pituitary, breast, and adipose tissue at 4 h after dosing when compared to rats fed low-fat diets. The transiently higher tissue concentrations of 14C-DMBA in rats fed a high-fat diet prior to DMBA administration correlate with the enhancement of mammary cancer induction seen when high-fat diets are fed prior to administration of this carcinogen.
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PMID:Hepatic and intestinal drug-metabolizing enzymes and the tissue distribution and excretion of 14C-7,12-dimethylbenz[a]anthracene in rats fed diets varying in fat concentration. 250 36

Comparison between the sequence of the gene coding for the wheat mitochondrial NADH dehydrogenase subunit IV (nad4) and the cDNA sequence obtained by reverse transcription, using total wheat mtRNA as template, has shown the presence of a uridine residue, not encoded by the genomic sequence, at the exon2-exon3 junction of the spliced transcript. This U creates a non-encoded CUG leucine codon which is essential for maintaining the reading frame, as shown by the conservation of the amino acid sequence of the NAD4 protein in various species. The addition of a U or the specific post-transcriptional conversion of a C to a U could explain this phenomenon.
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PMID:RNA editing at a splicing site of NADH dehydrogenase subunit IV gene transcript in wheat mitochondria. 268 23

The metabolism of chemical carcinogens was investigated in liver preparations from 28 captive woodchucks (Marmota monax). Of these, 23 were naturally infected with the woodchuck hepatitis virus (WHV), and eight also had primary hepatocellular carcinoma (PHC). Twenty-nine parameters were investigated in liver subcellular fractions, including cross-reactivity with HBsAg, and biochemical parameters, such as gamma-glutamyl transpeptidase, cytochrome P-450 and microsomal monooxygenases (aryl hydrocarbon hydroxylase, ethoxycoumarin and ethoxyresorufin deethylases, aminopyrine and dimethylnitrosamine demethylases, and testosterone 7 alpha-, 16 alpha- and 6 beta-hydroxylases), uridine 5'-diphosphoglucuronosyl transferase, GSH and related enzymes (peroxidase, reductase and S-transferase), as well as other cytosolic enzyme activities (glucose 6-phosphate and 6-phosphogluconate dehydrogenases, NADPH- and NADH-dependent diaphorases, and DT diaphorase). In addition, liver preparations were used in order to quantify the metabolic activation into bacterial mutagens of five procarcinogens (aflatoxin B1, the pyrolysis products Trp-P-2 and MeIQ, 2-aminofluorene and dimethylnitrosamine) and the decrease of potency of three direct-acting mutagens (sodium dichromate, ICR 191 and 4-nitroquinoline 1-oxide). WHV infection produced a significant stimulation of carcinogen metabolism, as shown by the simultaneous change in detoxification parameters (GSH depletion) and activation indices (enhancement of microsomal monooxygenases and of procarcinogen activation into mutagenic metabolites). There were no significant differences between WHV-positive samples from animals without PHC and the noncancerous tissue of PHC-bearing animals, whereas a decrease of both activation and detoxification indices was recorded in the tumorous tissue. There was a considerable interindividual variability among WHV carriers, which was tentatively ascribed to genetic factors. Pregnancy was the only known factor influencing the results in WHV carriers. However, even by excluding pregnant animals, the effects on carcinogen metabolism produced by WHV infection were still statistically significant. These results, together with previous data obtained in humans, revealed that metabolic factors may play a role in the synergism between viral hepatitis and chemical hepatocarcinogens in the etiopathogenesis of PHC.
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PMID:Enhanced metabolic activation of chemical hepatocarcinogens in woodchucks infected with hepatitis B virus. 272 Sep 3

In vivo effects of tetrahydrocannabinols (THCs) and their eight monooxygenated metabolites on the hepatic microsomal drug-metabolizing enzymes in mice were studied. delta 8-THC and its metabolites (7 alpha-hydroxy-, 7 beta-hydroxy- and 7-oxo-delta 8-THC, and 8 alpha, 9 alpha- and 8 beta, 9 beta-epoxyhexahydrocannabinol) tended to increase the enzyme contents or activities except for 7 beta-hydroxy-delta 8-THC which affected the microsomal enzymes in a different manner between the single and subchronic treatments. Single administration (5 mg/kg, i.v.) of 7-oxo-delta 8-THC, 8 alpha, 9 alpha- and 8 beta, 9 beta-epoxyhexahydrocannabinol led to the significant increase in hepatic microsomal p-nitroanisole O-demethylase and aniline hydroxylase activities accompanying a significant increase in cytochrome P-450 content in hepatic microsomes. The same results were obtained with subchronic treatment of mice with these metabolites (5 mg/kg/d, i.v. for 7 d), although the effect of 8 beta, 9 beta-epoxyhexahydrocannabinol on cytochrome P-450 was not statistically significant. 7 beta-Hydroxy-delta 8-THC significantly increased nicotinamide adenine dinucleotide phosphate (NADPH)-cytochrome c reductase and aniline hydroxylase activities by single administration, while the metabolite significantly decreased the contents of cytochrome b5 and P-450 and p-nitrophenol uridine diphosphate-glucuronyltransferase activity by the subchronic treatment. In contrast, delta 9-THC and its metabolites (8 alpha-hydroxy-, 8 beta-hydroxy- and 8-oxo-delta 9-THC) did not significantly affect the microsomal enzymes by both treatments except that the single administration of 8 alpha-hydroxy-delta 9-THC and the subchronic treatment of delta 9-THC significantly decreased NADPH-cytochrome c reductase activity.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:In vivo effects of tetrahydrocannabinols and their eight monooxygenated metabolites of the hepatic microsomal drug-metabolizing enzyme systems of mice. 283 34


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