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)

1. The intracellular distribution of nitrogen, DPNH cytochrome c reductase, succinic dehydrogenase, and cytochrome c oxidase has been studied in fractions derived by differential centrifugation from rat and guinea pig spleen homogenates. 2. In the spleens of each species, the nuclear fraction accounted for 40 to 50 per cent of the total nitrogen content of the homogenate, and the mitochondrial, microsome, and supernatant fractions contained about 8, 12, and 30 per cent of the total nitrogen, respectively. 3. Per mg. of nitrogen, DPNH cytochrome c reductase was concentrated in the mitochondria and microsomes of both rat and guinea pig spleens. Seventy per cent of the total DPNH cytochrome c reductase activity was recovered in these two fractions. The reductase activity associated with the nuclear fraction was lowered markedly by isolating nuclei from rat spleens with the sucrose-CaCl(2) layering technique. The lowered activity was accompanied by the recovery of about 90 per cent of the homogenate DNA in the isolated nuclei, indicating that little, if any, of the reductase is present in spleen cell nuclei. 4. Per mg. of nitrogen, succinic dehydrogenase was concentrated about 10-fold in the mitochondria of rat spleen, and 65 per cent of the total activity was recovered in this fraction. 5. Cytochrome c oxidase was concentrated, per mg. of nitrogen, in the mitochondria of both rat and guinea pig spleens. The activity associated with the nuclear fraction was greatly diminished when this fraction was isolated from rat spleens by the sucrose-CaCl(2) layering technique. Only 50 to 70 per cent of the total cytochrome c oxidase activity of the original homogenates was recovered among the four fractions from both rat and guinea pig spleens, while the specific activities of reconstructed homogenates were only 55 to 75 per cent of those of the original whole homogenates. This was in contrast to the results with DPNH cytochrome c reductase and succinic dehydrogenase where the recovery of total enzyme activity approached 100 per cent, and the specific activities of reconstructed homogenates equalled those of the original homogenates. The recovery of cytochrome c oxidase was greatly improved when only the nuclei were separated from rat spleen homogenates. 6. Data were presented comparing the concentrations (ratio of activity per mg. of nitrogen of the fraction to activity per mg. of nitrogen of the homogenate) of DPNH cytochrome c reductase in mitochondria and microsomes derived from different organs of different animals. 7. Data were presented comparing the activities per mg. of nitrogen of DPNH cytochrome c reductase in homogenates from several organs of various animals.
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PMID:Intracellular localization of enzymes in spleen. I. Reduced diphosphopyridine nucleotide cytochrome c reductase, cytochrome c oxidase, and succinic dehydrogenase in the rat and guinea pig. 1343 24

The classic spectrophotometric method for identification and characterization of respiratory enzymes has been used for the study of the cytochrome system of Aplysia. Particles have been prepared from the buccal mass and the gizzard muscles. Difference spectra taken on isolated particle suspensions show the presence of a complete cytochrome system composed of five components: cytochrome a, b, c, c(1), and a(3). As indicated by the peaks of the sharp absorption bands of their reduced forms, they are very similar to the cytochromes of mammals and yeast. Cytochrome a(3) has been identified as the terminal oxidase of Aplysia muscle by means of the spectrophotometric study of its carbon monoxide compound. Further evidence for the presence of a cytochrome system in Aplysia was obtained by assays of the catalytic activities of the isolated particles: succinic dehydrogenase, cytochrome oxidase, DPNH cytochrome c reductase. The cytochrome oxidase activity was strongly inhibited by carbon monoxide in the dark; the inhibition was totally relieved by light. Cytochrome c has been extracted and purified from muscle tissue. Its spectrum is almost identical with that of the mammalian pigment both in the oxidized and reduced forms. From the hepatopancreas a new respiratory enzyme has been extracted which has many physical and chemical properties in common with cytochrome h from terrestrial snails.
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PMID:Pathways of terminal respiration in marine invertebrates. II. The cytochrome system of Aplysia. 1366 20

Low (1 x 10(-9)M) concentrations of cytochrome c inhibit H2O2 production in cytochrome c-depleted mitochondria, purified succinate-cytochrome c reductase (SCR) and antimycin A inhibited cytochrome c-depleted HMP. At higher concentration (2 x 10(-6)M), cytochrome c eliminates pre-existed H2O2 if feeding electrons to it by succinate. Cytochrome c also decreases the OH* produced by succinate-cytochrome c reductase oxidizing succinate. We conclude that the alternative electron-leak pathway mediated by cytochrome c operates very well. In the presence of antimycin A, ferrocytochrome c can suppress the generation of H2O2 in SCR system, but ferricytochrome c cannot. Similar results are obtained on the elimination of pre-existed H2O2 by cytochrome c. For hydroxyl radical, antimycin A abolishes the suppression caused by both ferrocytochrome c and ferricytochrome c. These results indicate that the reductive state of cytochrome c caused by electron-flow is necessary and sufficient for the operation of cytochrome c-mediated electron-leakage pathway.
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PMID:The operation of the alternative electron-leak pathways mediated by cytochrome c in mitochondria. 1509 65

Cytochrome c is an important electron transfer protein in the respiratory chain, shuttling electrons from cytochrome c reductase to cytochrome c oxidase. Extensive chemical modification studies indicate significant electrostatic interactions between these proteins and show that all structural and conformational changes of cytochrome c can influence the electron transport. In the present work we examine the effect of an anticancer ruthenium complex, trans-Indazolium (bisindazole) tetrachlororuthenate(III) (HInd[RuInd(2)Cl(4)]), on the conformation of cytochrome c, the state of the heme moiety, formation of the protein dimer and on the folding state of apocytochrome c. For this purpose, gel-filtration chromatography, absorption second derivative spectroscopy, circular dichroism (CD) and inductively coupled plasma atomic emission spectroscopy (ICP(AES)) were used. The present data have revealed that binding of the potential anticancer drug HInd[RuInd(2)Cl(4)] complex to cytochrome c induces a conformation of the protein with less organized secondary and tertiary structure.
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PMID:Interaction of an anticancer ruthenium complex HInd[RuInd2Cl4] with cytochrome c. 1509 40

Cytochrome c (CYC) and 9 of the 13 subunits of cytochrome c oxidase (complex IV; COX) were previously shown to have accelerated rates of nonsynonymous substitution in anthropoid primates. Cytochrome b, the mtDNA encoded subunit of ubiquinol-cytochrome c reductase (complex III), also showed an accelerated nonsynonymous substitution rate in anthropoid primates but rate information about the nuclear encoded subunits of complex III has been lacking. We now report that phylogenetic and relative rates analysis of a nuclear encoded catalytically active subunit of complex III, the iron-sulfur protein (ISP), shows an accelerated rate of amino acid replacement similar to cytochrome b. Because both ISP and subunit 9, whose function is not directly related to electron transport, are produced by cleavage into two subunits of the initial translation product of a single gene, it is probable that these two subunits of complex III have essentially identical underlying rates of mutation. Nevertheless, we find that the catalytically active ISP has an accelerated rate of amino acid replacement in anthropoid primates whereas the catalytically inactive subunit 9 does not.
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PMID:Rapid nonsynonymous evolution of the iron-sulfur protein in anthropoid primates. 1590 47

1. One hundred and sixty 1-d-old Arbor Acre male broiler chicks were fed with maize-soybean based diets for 6 weeks in a 2 x 2 factorial experiment. The factors were CoQ10 supplementation (0 or 40 mg/kg) and Escherichia coli lipopolysaccharide (LPS) challenge (LPS or saline). 2. CoQ10 was supplemented from d 1. From d 18, the chickens received three weekly i.p. injections of LPS (1.0 mg/kg BW) or an equivalent amount of sterile saline as control. From d 10 on, all chickens were exposed to low ambient temperature (12 to 15 degrees C) to induce ascites. 3. The blood packed cell volume and ascites heart index of broiler chickens were reduced by dietary CoQ10 supplementation. Mitochondrial State 3 and State 4 respiration, respiratory control ratio and phosphate oxygen ratio were not changed, but H+/site stoichiometry of complex II + III was elevated by dietary CoQ10 supplementation. 4. Cytochrome c oxidase and H+-ATPase activity were increased by CoQ10 supplementation, whereas NADH cytochrome c reductase and succinate cytochrome c reductase were not influenced. Mitochondrial anti-ROS capability was increased and malondialdehyde content was decreased by CoQ10 supplementation. 5. The work suggested that dietary CoQ10 supplementation could reduce broiler chickens' susceptibility to ascites, which might be the result of improving hepatic mitochondrial function, some respiratory chain-related enzymes activities and mitochondrial antioxidative capability.
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PMID:Effects of dietary coenzyme Q10 supplementation on hepatic mitochondrial function and the activities of respiratory chain-related enzymes in ascitic broiler chickens. 1635 19

Tirandamycin inhibits respiration and phosphorylation in rat liver mitochondria. An investigation of individual reaction sequences occurring within the respiratory chain showed that the antibiotic stimulates reduced nicotinamide adenine dinucleotide (NADH)- and succinate-linked coenzyme Q reductase. NADH-linked reduction of tetrazolium salts remains unaffected by tirandamycin. Succinotetrazolium salt reductase is inhibited significantly. Reduction of cytochrome c by succinate is blocked by the antibiotic; NADH-cytochrome c reductase is inhibited but not completely blocked. Cytochrome c oxidase remains unaffected. Mitochondrial difference spectra prepared in the presence of tirandamycin indicate that the reduction of cytochrome b is not impaired but no reduction of cytochromes c or a is apparent. These results indicate that tirandamycin interferes with the respiratory chain at a point beyond the cytochrome b and prior to the cytochrome c reduction site. Tirandamycin acts also as a potent inhibitor of ribonucleic acid polymerase as discussed in the foregoing paper.
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PMID:Tirandamycin: inhibition of oxidative phosphorylation in rat liver mitochondria. 1655 5

Cytochrome c oxidase has been purified from Zea mays mitochondria by a solubilization with dodecyl maltoside followed by a simple and rapid two step fast protein liquid chromatographic method involving anion exchange on Mono Q and size exclusion chromatography on Superose 12. The preparation obtained was resolved by urea sodium dodecyl sulfate-polyacrylamide gel electrophoresis and had a subunit composition comprising polypeptides of apparent molecular masses of 48, 31, and 25 kilodaltons at least one at 16 and 11 kilodaltons and three subunits below 10 kilodaltons. Comparison with a purified yeast cytochrome c oxidase revealed that the four largest subunits showed similar electrophoretic mobilities. Subunits I and II cross-reacted with antibodies raised against the yeast homologous polypeptides. Polypeptides of the plant ubiquinone:cytochrome c reductase complex have also been identified by cross-reaction with antibodies raised against yeast cytochrome b and c(1) subunits and by inference from comigration.
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PMID:Subunit Composition of Cytochrome c Oxidase in Mitochondria of Zea mays. 1666 13

Although it has been shown that endothelial nitric oxide synthase (eNOS)-derived nitric oxide downregulates mitochondrial oxygen consumption during early reperfusion, its effects on inducible NOS (iNOS) induction and myocardial injury during late reperfusion are unknown. Wild-type (WT) and eNOS(-/-) mice were subjected to 30 min of coronary ligation followed by reperfusion. Expression of iNOS mRNA and protein levels and peroxynitrite production were lower in postischemic myocardium of eNOS(-/-) mice than levels in WT mice 48 h postreperfusion. Significantly improved hemodynamics (+/-dP/dt, left ventricular systolic pressure, mean arterial pressure), increased rate pressure product, and reduced myocardial infarct size (18 +/- 2.5% vs. 31 +/- 4.6%) were found 48 h after reperfusion in eNOS(-/-) mice compared with WT mice. Myocardial infarct size was also significantly decreased in WT mice treated with the specific iNOS inhibitor 1400W (20.5 +/- 3.4%) compared with WT mice treated with PBS (33.9 +/- 5.3%). A marked reperfusion-induced hyperoxygenation state was observed by electron paramagnetic resonance oximetry in postischemic myocardium, but Po(2) values were significantly lower from 1 to 72 h in eNOS(-/-) than in WT mice. Cytochrome c-oxidase activity and NADH dehydrogenase activity were significantly decreased in postischemic myocardium in WT and eNOS(-/-) mice compared with baseline control, respectively, and NADH dehydrogenase activity was significantly higher in eNOS(-/-) than in WT mice. Thus deficiency of eNOS exerted a sustained beneficial effect on postischemic myocardium 48 h after reperfusion with preserved mitochondrial function, which appears to be due to decreased iNOS induction and decreased iNOS-derived peroxynitrite in postischemic myocardium.
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PMID:Endothelial nitric oxide synthase (NOS3) knockout decreases NOS2 induction, limiting hyperoxygenation and conferring protection in the postischemic heart. 1711 45

Cytochrome c release from mitochondria induces caspase activation in cytosols; however, it is unclear whether the redox state of cytosolic cytochrome c can regulate caspase activation. By using cytosol isolated from mammalian cells, we find that oxidation of cytochrome c by added cytochrome oxidase stimulates caspase activation, whereas reduction of cytochrome c by added tetramethylphenylenediamine (TMPD) or yeast lactate dehydrogenase/cytochrome c reductase blocks caspase activation. Scrape-loading of cells with this reductase inhibited caspase activation induced by staurosporine. Similarly, incubating intact cells with ascorbate plus TMPD to reduce intracellular cytochrome c strongly inhibited staurosporine-induced cell death, apoptosis, and caspase activation but not cytochrome c release, indicating that cytochrome c redox state can regulate caspase activation. In homogenates from healthy cells cytochrome c was rapidly reduced, whereas in homogenates from apoptotic cells added cytochrome c was rapidly oxidized by some endogenous process. This oxidation was prevented if mitochondria were removed from the homogenate or if cytochrome oxidase was inhibited by azide. This suggests that permeabilization of the outer mitochondrial membrane during apoptosis functions not just to release cytochrome c but also to maintain it oxidized via cytochrome oxidase, thus maximizing caspase activation. However, this activation can be blocked by adding TMPD, which may have some therapeutic potential.
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PMID:Mitochondrial regulation of caspase activation by cytochrome oxidase and tetramethylphenylenediamine via cytosolic cytochrome c redox state. 1769 99


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