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 respiratory systems of the mother cells and forespores of Bacillus cereus were compared throughout the maturation stages (III to VI) of sporulation. The results indicated that both cell compartments contain the same assortment of oxidoreductases and cytochromes. However membrane fractions from young forespores were clearly distinct from those of the mother cell, i.e., lower content of cytochrome aa3, lower cytochrome c oxidase activity, higher concentration of cytochrome o, and a lower sensitivity of the respiration to the inhibiting effect of cyanide. This suggests that the cyanide-resistant pathway contributes more importantly to forespore respiratory activity than to activity in the mother cell compartment. During the maturation stages, the forespore NADH oxidase activity declined faster than in the mother cells. Other activities studied decreased steadily in both cell compartments. These findings together with the analysis of the kinetics of NADH-dependent reduction of cytochromes in the mature spore membranes indicated an impairment of electron flow between NADH dehydrogenase and cytochrome b. This impairment could be overcome by the addition of menadione.
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PMID:Respiratory systems of the Bacillus cereus mother cell and forespore. 309 18

A 3-week-old girl with failure to thrive and cardiomegaly died of cardiac arrest at age 4 weeks. Morphologic studies of the heart showed enlarged muscle fibers with large accumulations of mitochondria, characteristic of histiocytoid cardiomyopathy. Biochemical studies showed markedly decreased succinate-cytochrome c reductase and rotenone-sensitive NADH-cytochrome c reductase activities, while other mitochondrial enzymes were normal. In isolated mitochondria, cytochrome spectra showed a severe defect of reducible cytochrome b and a less marked defect of cytochrome cc1, while the content of cytochrome aa3 (cytochrome c oxidase) was normal. Histiocytoid cardiomyopathy appears to be due to a defect of complex III (reduced coenzyme Q-cytochrome c reductase) in the respiratory chain of heart mitochondria.
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PMID:Histiocytoid cardiomyopathy of infancy: deficiency of reducible cytochrome b in heart mitochondria. 609 33

Among 979 non-glycerol growers of the yeast Schizosaccharomyces pombe, 40 strains were found to be deficient in the mitochondrial ATPase activity. Three of them exhibited an alteration in either the alpha or beta subunits of the F1ATPase. The alpha subunit was not immunodetected in the A23/13 mutant. The beta subunit was not immuno-detected in the B59/1 mutant. The existence of these two mutants shows that the alpha and beta subunits can be present independently of each other in the inner mitochondrial membrane. The beta subunit of the mutant F25/28 had a slower electrophoretic mobility than that of the wild-type beta subunit. This phenotype indicates abnormal processing or specific modification of the beta subunit. All mutants showed reduced activities of the NADH-cytochrome c reductase and of the cytochrome oxidase and a decreased synthesis of cytochrome aa3 and cytochrome b. This pleiotropic phenotype appears to result from specific modifications in the mitochondrial protein synthesis. The mitochondrial synthesis of four polypeptides (three cytochrome oxidase and one cytochrome b subunits) was markedly decreased or absent while three new polypeptides (Mr = 54000, 20000 and 15000) were detected in all the mutants analysed. This observation suggests that a functional F1ATPase is necessary for the correct synthesis and/or assembly of the mitochondrially made components of the cytochrome oxidase and cytochrome b complexes.
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PMID:Alterations of the alpha or beta subunits of the mitochondrial ATPase in yeast mutants. 621 96

Cell lines resistant to ethidium bromide have been developed from cultured mammalian BHK21/C13 cells and these same cells transformed by Rous sarcoma virus (C13/B4). Cells resistant to 2 micrograms ethidium bromide per milliliter have been cloned. One clone of the control and one of the virus-transformed cell lines has been employed for characterization. The resistant cells, in the presence of 2 micrograms ethidium bromide/ml, grow at approximately the same rate as the untreated parental cells. The control cells possess a "normal" karyotype (44 chromosomes), while the corresponding ethidium bromide mutant has a reduced chromosome number of 41 and a number of translocations. The mitochondria displayed morphological alterations compared to the parental lines during the transition phase prior to the isolation of the ethidium bromide-resistant cells. The mitochondria of the ethidium bromide-resistant mutants appear somewhat enlarged with a normal morphology. The effect of ethidium bromide on selected respiratory enzymes in normal and virus-transformed ethidium bromide-resistant baby hamster kidney cells was determined. Ethidium bromide-resistant cells exhibited a depressed level of cytochrome aa3. This depression could not be reversed by growth in ethidium bromide-free media. Ethidium bromide-resistant cells possessed the same cytochrome b, c, and c1 levels per cell as their corresponding parental lines. Purified mitochondria isolated from virus-transformed ethidium bromide-resistant cells exhibited a depression in cytochrome oxidase-specific activity, while the ethidium bromide-resistant control cells did not. All cell lines studied showed a depression in NADH-ferricyanide and NADH-cytochrome c reductase-specific activities relative to their parental BHK21/C13 cells. No increase was observed in virus-transformed ethidium bromide-resistant cells. Ethidium bromide-resistant control cells exhibited a two-fold increase in oligomycin-insensitive adenosine triphosphatase activity relative to their parental cells. All of the cell lines studied possessed equivalent oligomycin-sensitive adenosine triphosphatase-specific activity except for the virus-transformed, dye-resistant mutant, whose activity was increased.
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PMID:Control and virus-transformed baby hamster kidney cells resistant to ethidium bromide. I. Characterization and the respiratory enzymes. 625 Oct 98

Mammary gland and liver microsomes of lactating rats were examined for the components of mixed function oxidase and related enzyme activities. Cytochrome b5, NADH- and NADPH- dependent cytochrome c reductase activities were 15-, 6- and 10-fold lower, respectively, in the mammary gland than in the liver microsomes. The determination of cytochrome P-450 (P-448) in the mammary gland microsomes required elimination of the spectral interferences by hemoglobin and cytochrome aa3. The presence of the latter in this fraction was also shown by cytochrome c oxidase activity. Cytochrome aa3 was reduced by anaerobic incubation of mammary gland microsomes, in the presence of antimycin A, with sodium succinate, phenazine ethosulfate, and sodium ascorbate for 30 min at room temperature. Spectral resolution of the dithionite-reduced cytochrome P-450 (P-488) carbon monoxide complex occurred 30 min after gassing. The basal level of cytochrome P-450 was about 500-fold greater in the liver than in the mammary gland microsomes. Pretreatment of lactating rats with the inducers of hepatic cytochrome P-448, 3-methylcholanthrene and beta-naphthoflavone, increased the cytochrome content 3- to 10-fold, in the mammary gland and liver microsomes, respectively. The induction of cytochrome P-448 in microsomes of both tissues was also shown by type I binding spectra obtained with N-2-fluorenylacetamide. Using hydroxylation of benzo[a]pyrene and N-2-fluorenylacetamide as a measure of mixed function oxidase activity, we found that the basal activities, which were 4- to 8-fold greater in the liver microsomes, were increased in both tissues after treatment of rats with the inducers. The induced activities were inhibited by 0.1 micrometers alpha-napthoflavone in vitro, indicating a dependence on cytochrome P-448. The data suggest that the mammary gland, an extrahepatic target for carcinogens, is capable of their metabolism.
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PMID:Mixed function oxidase in the mammary gland and liver microsomes of lactating rats. Effects of 3-methylcholanthrene and beta-naphthoflavone. 627 40

A partial deficiency of cytochrome oxidase has been found in 7 patients with chronic progressive external ophthalmoplegia and proximal myopathy or craniosomatic abnormalities. Muscle biopsies from all these patients showed morphological mitochondrial abnormalities ("ragged red" fibres) and cytochemical assay of cytochrome oxidase showed that these fibres contained no demonstrable enzyme activity. The incidence of cytochrome oxidase-negative fibres was greater than that of "ragged-red" fibres suggesting that the enzyme defect preceded the development of morphological mitochondrial changes. Biochemical analysis of skeletal muscle mitochondrial fractions from 3 patients revealed in 1 case a significantly lower concentration of cytochrome aa3 and a decreased ratio of cytochrome oxidase/succinate-cytochrome c reductase. Fasting blood metabolites were elevated in 2 patients. We suggest that partial cytochrome oxidase deficiency is the underlying defect in mitochondrial myopathy associated with the oculocraniosomatic syndromes.
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PMID:A partial deficiency of cytochrome c oxidase in chronic progressive external ophthalmoplegia. 630 77

Epithelial and connective tissue compartments of rat oral mucosa were dissociated after incubation with elastase +/- soybean trypsin inhibitor (SBTI). Elastase + SBTI induced greater ultrastructural damage within the dissociated compartments than elastase alone. The basal lamina remained with the epithelial layer after elastase separation and was destroyed after exposure to elastase + SBTI. Isolated epithelial mitochondria were more severely damaged ultrastructurally after elastase + SBTI separation of the compartment than those prepared after exposure to elastase alone. Isolated fibroblast mitochondria were damage to the same extent after dissociation of the compartment with either medium. Oxidative metabolism and mitochondrial recoveries declined significantly after exposure to either dissociating medium. Cytochrome oxidase activity was significantly greater than succinic cytochrome c reductase in the control and experimental groups. Oxidative metabolism was found to be significantly greater in the connective tissue compartment than the epithelial compartment after dissociation of immature rat oral mucosa. Our data suggests that caution be utilized in assessing cellular viability and oxidative metabolism in tissue compartments immediately after their dissociation by proteolytic enzymes.
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PMID:Elastase +/- soybean trypsin inhibitor dissociation of rat oral mucosa: ultrastructural and oxidative metabolic destructive changes in isolated, epithelial and dermal mitochondria after dissociation. 690 88

Proximal tubules were isolated in highly pure form from rabbit cortices by a mechanical procedure that is known to preserve the structural and metabolic aspects of the tubular cells. Postnuclear supernates prepared from the isolated tubules were subjects to isopycnic centrifugation in linear sucrose gradients. The enzyme activities associated with the plasma membrane (gamma-glutamyl transpeptidase, amino-peptidase M, alkaline phosphatase, Na-K-ATPase, and phosphodiesterase I) exhibited sharp unimodal frequency-density profiles with a median density near 1.16 g/ml, which shifted to a heavier density when treated with digitonin. The lysosomal enzymes, N-acetyl-beta-glucosaminidase, alpha-mannosidase, and cathepsin B, and the peroxisomal enzyme catalase exhibited particle-associated activity near a density of 1.22 g/ml. Disruption of these particles by freezing and thawing resulted in these activities appearing in the rho = 1.10 g/ml region of the gradient where the soluble cytosolic enzyme, phosphoglucomutase, exhibited activity. Cytochrome oxidase activity typical of mitochondria gave a sharp unimodal profile at rho = 1.18 g/ml. Microsomal glucose-6-phosphatase and NADPH: cytochrome c reductase activities gave median densities near 1.16 g/ml, which did not change after incubation with digitonin. Galactosyl transferase activity gave a skewed profile at rho = 1.16 g/ml and showed a slight shift to heavier density after digitonin. This study of the enzymatic activities and density gradient distribution of the components of the proximal tubule cells provides the methodology for the further study of the cellular processing of endogenous and exogenous substances by this vital cell type.
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PMID:Analytical cell fractionation of isolated rabbit renal proximal tubules. 730 Jan 16

Mitochondrial biogenesis was studied during differentiation of two immortalized cell lines (C2C12, 3T3) with enzyme measurements, Northern blots, and quantitative ultrastructure. Citrate synthase, isocitrate dehydrogenase, and 3-hydroxyacyl-CoA dehydrogenase (nuclear encoded, mitochondrial matrix location) showed linear, four- to sixfold increases in enzymatic activity in C2C12 cells but increased exponentially in 3T3 cells. Cytochrome oxidase and NADH dehydrogenase (nuclear and mitochondrial encoded, cristae location) increased to a lesser extent and with a pattern dissimilar to the first group. Northern blots and activity of succinate dehydrogenase (cristae location but entirely nuclear encoded) suggested the groupings were based on location of the genes rather than the mature enzyme. However, quantitative electron microscopy and comparisons with adult tissue suggested that mitochondrial ultrastructure can influence the change in cristae enzymes. Cristae surface area per unit mitochondrial volume and per unit cell volume increased much less than did cristae enzymes. Available space on the inner membrane may become limiting and account for some aspects of the pattern of change in electron transport enzymes during differentiation.
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PMID:Mitochondrial biogenesis during cellular differentiation. 914 61

The effect of galactosamine on liver mitochondrial functions was studied in vivo in rats at 12hr, 24hr and 36hr after the administration of the drug. State 3 respiration decreased significantly with both NAD+ linked and FAD linked substrates. Respiratory control ratio, an index of membrane integrity and P/O ratio which is a measure of phosphorylation efficiency decreased significantly. There was a significant decrease in the activities of NADH dehydrogenase, succinate dehydrogenase and cytochrome oxidase. A significant decrease was also seen on membrane potential, cytochrome aa3, cytochrome b, cytochrome c and on phospholipids of mitochondria. The observed mitochondrial dysfunctions were related to increased lipid peroxidation, which could cause loss of membrane integrity and a decreased rate of phosphorylation. It is proposed that increased lipid peroxidation was responsible for the inhibition on both oxidation and phosphorylation in mitochondria in galactosamine treated rats.
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PMID:Effect of administration of galactosamine hydrochloride on rat liver mitochondria. 942 49


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