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:1.6.99.3 (diaphorase)
5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Previous studies have shown that the bacterium, Vitreoscilla, generates a respiratory-driven delta psi Na+. Two major respiratory electron transport proteins, NADH dehydrogenase (NADH:Quinone oxidoreductase), and cytochrome o terminal oxidase are candidates for the electrogenic Na+ pumping that mediates the delta psi Na+ formation. The NADH oxidase activity of the membranes was enhanced more by Na+ than by Li+. The NADH:Quinone oxidoreductase activity in the respiratory chain was enhanced by Na+ and Li+, whereas the quinol oxidase activity of cytochrome o was enhanced specifically by Na+, and not by Li+, K+, or choline. Purified cytochrome o, reconstituted into Na(+)-loaded liposomes in the right-side-out orientation, catalyzed a net Na+ extrusion when energized with Q1H2(1). In nonloaded inside-out proteoliposomes, this cytochrome catalyzed a net uptake of 22Na+ when energized with ascorbate/TMPD. Both Na(+)-pumping activities were inhibited by CN-. These results are consistent with the Vitreoscilla cytochrome o being a redox-driven Na+ pump.
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PMID:A cytochrome that can pump sodium ion. 225 29

Adult rats of either sex and mature females ovariectomized 44 days earlier, were partially hepatectomized under ether anesthesia, leading to two-thirds organ removal. The respective controls were incised and the livers manipulated by hand. At specified p.o. periods, hepatic microsomal total protein, cytochrome P-450 and activities of the enzymes, aminopyrine demethylase and benzo[a]pyrene hydroxylase were determined for the respective pairs and submitted to analysis of variance. The data are expressed as ratios of the sham-operated to the partially hepatectomized group mean values on a percentage basis. For one male series, cytochrome P-450 and the 2 enzyme activities were significantly elevated with the intact rats at 72 and 96 h and 10 days and in yet another series of the same sex, the findings were similar except that only the cytochrome level of the controls was increased at day 10; the ratios normalized by day 21. As screened in a few groups, the changes in microsomal NADPH cytochrome c reductase were not noteworthy. Possible latency periods were shorter for the female series and the hydroxylase activity was elevated in the intact liver microsomes over test periods of 24 h to 10 days. In general, although a trend of increased parameter value for the intact group was apparent and in agreement with several published reports, statistical significance could not be substantiated in many instances, wide variations and sporadic data being encountered. None of the intact group changes in the constants were significant with the ovariectomized series. The effect of an inducer, phenobarbital, was determined in relation to the 10 day-ratios derived for males fed a casein based control diet as such and supplemented with 30 wt % each of glucose, fructose, galactose, maltose and lactose, the last one being screened only in partially hepatectomized rats. Phenobarbital was injected i.p. daily at 80 mg/kg on the last 3 days. Among other changes noted with the respective ratios, each of the intact groups displayed remarkable elevations in the total protein content. Additional comparisons are also advanced for the individual group parameter findings in relation to the control diet- and the 30% glucose-fed animals.
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PMID:Variations in microsomal parameters of intact and regenerating rat liver with time and on feeding high carbohydrate diets. 235 31

NADPH-cytochrome P-450 reductase (EC 1.6.2.4), the enzyme involved in progesterone 17-hydroxylation, was purified to apparent homogeneity by detergent solubilization of the microsomal fractions of liver and testis from untreated rats. The enzymes from these two tissues were then compared with regard to several parameters. The liver and testicular reductases have the same subunit mol wt (79,000), determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), and have similar specific activity for cytochrome c reduction (48.1 and 58.2 mumol min-1 mg-1, respectively). The absolute flavin absorption spectra of liver and testicular reductase were very similar. The spectra of native, reduced, and oxidized reductases were characteristic of flavoprotein with two flavin groups. The Km values for NADPH during cytochrome reduction were shown to be the same, within experimental error (5.29 +/- 0.46 microM-1 for liver and 4.37 +/- 0.53 microM-1 for testis). Monospecific antiserum was prepared against both rat liver and testicular reductases. There were no antigenic differences demonstrated by immunological tests using either antibody preparation. Antiliver reductase antiserum was shown to inhibit testicular microsomal progesterone 17-hydroxylase activity by 70%. Testicular cytochrome c reductase activity was inhibited by 94%, and liver cytochrome c reductase activity was inhibited by 85%. Peptide maps of both forms of reductase isolated from immunoprecipitates showed very similar patterns after enzymatic proteolysis. These results indicate that microsomal NADPH-cytochrome P-450 reductase involved in steroid hydroxylations in untreated rat liver and testis could not be distinguished from each other by these methods and, therefore, are probably the same protein.
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PMID:NADPH-cytochrome P-450 reductase from untreated rat testicular and liver microsomes: isolation and comparison. 242 90

Previous studies have shown that behavioral and neurophysiological responses to tastes develop during rat's postnatal life. The present experiments evaluated morphological and metabolic development of neurons in the gustatory zone of the caudal parabrachial nucleus (PBNc) of rat. Histological reconstruction studies were conducted to establish coordinate systems for PBNc gustatory zones in developing rats. Reliability of coordinate systems were evaluated in separate experiments following infusions of horseradish peroxidase in the thalamic taste area. Morphological and Golgi impregnation studies were performed to characterize neuronal and dendritic architecture in PBNc gustatory zones defined by coordinates. Conventional histochemical studies were performed for the mitochondrial respiratory enzymes cytochrome C oxidase (CO; EC 1.9.3.1) succinate dehydrogenase (SDH; EC 1.3.99.1), and NADH-dehydrogenase (NADH-DH; EC 1.6.99.3). Results show that two somatic morphologies can be statistically characterized in PBNc gustatory zones: Multipolar somatic types and fusiform somatic types. Multipolar and fusiform neurons of neonatal and adult rats project axons to the thalamic taste area, and dendrites of these neurons grow extensively between approximately 16 days after birth to approximately 35 days after birth. Activity of CO, SDH, and NADH-DH increases in the PBNc gustatory zones during the period of dendritic growth, and continues to increase slightly to approximately 45 days. These results provide the first demonstration of postnatal morphological and metabolic developmental in a central gustatory relay. Postnatal development of gustatory system therefore appears similar to that reported for other sensory systems, to the extent that morphological and metabolic development accompanies the ontogeny of taste responses.
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PMID:Postnatal development of the parabrachial gustatory zone in rat: dendritic morphology and mitochondrial enzyme activity. 246 23

Bloodstream forms of Trypanosoma brucei brucei (EATRO 110) were cultured with 100 microM difluoromethylornithine (DFMO). After 48 hr, intracellular putrescine was depleted and cells were positive when histochemically stained for the mitochondrial marker enzyme, NAD diaphorase, and exhibited mitochondrial proliferation and cristae development when examined by electron microscopy. This suggested that the mitochondrion was undergoing the physiological transformation necessary for successful transmission of the bloodstream form to the vector, namely the initiation of development of a TCA cycle and cytochrome system. The short stumpy forms that appeared by day 4 of culture, although physiologically transformed, were not viable in so far as they were not capable of transforming to procyclic trypomastigotes when introduced into SDM-79 medium. When rats infected with T. b. brucei were given 4% (w/v) DFMO in their drinking water, they were cured within 72 hr. Trypanosomes removed from animals and stained for NAD diaphorase showed mitochondrial transformation, as well as an intermediate and short stumpy morphology, at 36 and 60 hr, respectively. Data from this study on the growth and transformation characteristics of the DFMO induced intermediate and short stumpy form trypanosomes supports the observation that the intermediate form, and not the short stumpy form, is able to successfully transform to procyclic trypomastigotes.
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PMID:Physiological activation of the mitochondrion and the transformation capacity of DFMO induced intermediate and short stumpy bloodstream form trypanosomes. 249 2

The NAD(P)H:menadione oxidoreductase gene (Nmo-1) codes for a quinone reductase (also called DT diaphorase; EC 1.6.99.2) believed to play a central role in protection against oxidative stress. We have studied mice with a radiation-induced chromosomal deletion involving the albino locus (c) on chromosome 7 and found that Nmo-1 mRNA levels and the rate of Nmo-1 gene transcription are markedly increased (greater than 100-fold and greater than 12-fold, respectively) in the untreated c14CoS/c14CoS deletion homozygote, compared with the untreated Cch/Cch wild-type and the Cch/C14CoS heterozygote. These data suggest that a gene located on chromosome 7 encodes a trans-acting regulatory factor that might be a negative effector of the Nmo-1 gene, which we show here is located on chromosome 8 approximately 1.4 centimorgans (about 1000 kilobase pairs) from the Es-2 gene. Conversely, there are no detectable basal levels of cytochrome P1450 (Cyp1a1 gene) or cytochrome P3450 (Cyp1a2 gene) mRNA, indicating that the regulation of basal expression of the Cyp1a1 and Cyp1a2 genes is distinct from that of the Nmo-1 gene. Moreover, the Cyp1a1 and Cyp1a2 genes and the Nmo-1 gene are induced by tetrachlorodibenzo-p-dioxin in the cch/cch, cch/c14CoS, and c14CoS/c14CoS mice. The mechanism of tetrachlorodibenzo-p-dioxin inducibility of the Cyp1a1, Cyp1a2, and Nmo-1 genes is, therefore, independent of the mechanism of Nmo-1 gene activation in untreated c14CoS/c14CoS mice.
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PMID:Marked increases in hepatic NAD(P)H:oxidoreductase gene transcription and mRNA levels correlated with a mouse chromosome 7 deletion. 250 56

The electrostatically stabilized complex between Anabaena variabilis ferredoxin--NADP+ reductase and Azotobacter vinelandii flavodoxin has been covalently cross-linked by treatment with 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide. The covalent complex exhibits a molecular mass and FMN/FAD content consistent with that expected for a 1:1 stoichiometry of the two flavoproteins. Immunochemical cross-reactivity is exhibited by the covalent complex with rabbit antisera prepared separately against each protein. The complex retains NADPH-ferricyanide diaphorase activity although the Km for ferricyanide is increased twofold and the turnover number is decreased by a factor of two when compared to native reductase. NADPH-cytochrome-c reductase activity of the complex is observed at a level that is quite similar to that determined at saturating concentrations of flavodoxin, while it is only 1-2% of that exhibited by the reductase in the presence of ferredoxin. No stimulation of cytochrome-c reductase activity is observed on adding ferredoxin to the cross-linked complex. Stopped-flow data show that covalent cross-linking of the flavodoxin to the reductase reduces the rate of electron transfer from its semiquinone form to cytochrome c by a factor of 60. Anaerobic titrations of the reduced complex with NADP+ show the semiquinone/quinol couple of the flavodoxin is increased 100 mV relative to the free form and the quinone/quinol couple of complexed ferredoxin-NADP+ reductase is increased by only 25 mV, relative to the free protein. Addition of NADPH to the cross-linked complex reduces the FAD of the reductase as well as the FMN moiety of flavodoxin to a mixture of semiquinone and quinol forms.
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PMID:Preparation and properties of a cross-linked complex between ferredoxin--NADP+ reductase and flavodoxin. 250 11

A strain of yeast lacking the gene for the Rieske iron-sulfur protein (RIP) of the cytochrome b-c1 complex was used to study the assembly of this complex in the mitochondrial membrane. This strain lacks the mRNA for the iron-sulfur protein as evidenced by both Northern hybridization using a probe containing the coding region of the gene plus in vitro translation of total RNA followed by immunoprecipitation with a specific antibody against the iron-sulfur protein. In addition, isolated mitochondria from this strain lacked cytochrome c reductase activity with either succinate or the decyl analog of ubiquinol as substrate. Immunoblotting studies with antiserum against the cytochrome b-c1 complex revealed that mitochondria from the iron-sulfur protein-deficient strain have levels of core protein I, core protein II, and cytochrome c1 equal to those of wild-type mitochondria; however, a decrease in cytochrome b was evident from both immunoblotting and spectral analysis. Moreover, it is evident from the immunoprecipitates of radiolabeled mitochondria that the amounts of the low-molecular-weight subunits (17, 14, and 11 kDa) are decreased 53, 65, and 50%, respectively, in mitochondria lacking the iron-sulfur protein. These results suggest that the iron-sulfur protein is required for the complete assembly of the low-molecular-weight subunits into the cytochrome b-c1 complex.
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PMID:The iron-sulfur protein is necessary for the complete assembly of the low-molecular-weight subunits into the cytochrome b-c1 complex of yeast mitochondria. 253 36

A ubiquinone derivative, 3-chloro-5-hydroxyl-2-methyl-6-decyl- 1,4-benzoquinone (3-CHMDB), which shows different effects on the mitochondrial cytochrome b-c1 complex and chloroplast cytochrome b6-f complex, has been synthesized and characterized. When the cytochrome b-c1 complex is treated with varying concentrations of 3-CHMDB and assayed at constant substrate (Q2H2) concentration, a 50% inhibition is observed when 2 mol of 3-CHMDB per mol of enzyme are used. The degree of inhibition is dependent on the substrate concentration. When ubiquinol-cytochrome c reductase is treated with 2 mol of 3-CHMDB per mol of enzyme, less inhibition is observed with a lower substrate concentration, suggesting the possible existence of two forms of reductases: one with a high affinity for ubiquinone and another with a low affinity. 2-Chloro-5-hydroxyl-3-methyl-6-decyl-1,4-benzoquinone (2-CHMDB), an isomer of 3-CHMDB, shows much less inhibition of the mitochondrial cytochrome b-c1 complex, suggesting that the quinone binding site in this complex is highly specific. In contrast to the inhibition observed with the cytochrome b-c1 complex, 3-CHMDB causes no inhibition of the plastoquinol-plastocyanin reductase activity of chloroplast cytochrome b6-f complex, regardless of whether plastoquinol-2 or ubiquinol-2 is used as substrate. 3-CHMDB restores the dibromothymoquinone-altered EPR spectra of iron-sulfur protein in both complexes. In the case of the cytochrome b6-f complex, 3-CHMDB also partially restores the dibromothymoquinone-inhibited activity. Reduced form 3- or 2-CHMDB is oxidizable by the cytochrome b6-f complex, but not by the cytochrome b-c1 complex. These results suggest that the quinol oxidizing sites in the cytochrome b6-f complex may differ from those in the mitochondrial cytochrome b-c1 complex.
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PMID:A ubiquinone derivative that inhibits mitochondrial cytochrome b-c1 complex but not chloroplast cytochrome b6-f complex activity. 253 47

The tissues of hepatocellular carcinoma were operatively resected from six patients. All four components of the systems of microsomal cytochrome P-450-linked monooxygenase of the tissues were investigated and compared to those of normal liver tissue. The concentrations of cytochromes P-450, P-420 and b5 were measured optically and the concentrations of all components except cytochrome P-450 were measured by the Western blotting method followed by immunochemical staining. In microsomes of hepatocellular carcinoma tissues, there was as much cytochrome P-450 and other redox components as in the normal liver tissues, but cytochrome P-450 in liver cancer tissues was unstable and easily converted to cytochrome P-420. The specific activities of NADPH- and NADH-ferricyanide and cytochrome c reductase of each sample were also measured. In the microsomes of the cancer tissues, the specific activities were remarkably reduced compared with those of normal liver tissues. The lipid compositions of the microsomes and the phospholipid/cholesterol ratios (w/w) were 13.1 +/- 3.13 in the cancer tissues and 43.0 +/- 6.74 in normal liver tissues. This difference of the lipid composition elucidates the instability of cytochrome P-450 molecules and the inefficiency of the electron transport of cytochrome P-450-linked monooxygenase systems.
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PMID:Microsomal cytochrome P-450-linked monooxygenase systems and lipid composition of human hepatocellular carcinoma. 254 14


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