Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.6.5.3 (complex I)
 8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Chinese hamster subunits of mitochondrial respiratory Complex I (NADH-ubiquinone reductase), Complex IV (cytochrome c oxidase), and Complex V (oligomycin-sensitive ATPase) were identified by immunoprecipitation and/or Western immunoblotting with antibody to the corresponding beef heart complexes. In the Chinese hamster lung cell mutant Gal 32, cytochrome c oxidase activity and its mitochondrially synthesized subunits (I, II, and III) are substantially decreased, but a cytoplasmically synthesized subunit (IV) is present at wild type levels. Complex I activity and five of its subunits are greatly diminished in Gal 32; several of the affected Complex I subunits correspond in mobility to mitochondrial translation products. In contrast, ATPase activity and its mitochondrially and cytoplasmically synthesized subunits are not greatly modified in the mutant. Our data suggest that the ATPase complex contains two rather than one mitochondrially synthesized peptides. The simultaneous correction of this pleiotropic phenotype in a spontaneous revertant of Gal 32 selected for its ability to grow on galactose suggests that the Gal 32 phenotype is a consequence of a single mutation. Therefore, it is concluded that Complex I may contain a previously unrecognized mitochondrially synthesized subunit(s), and that the lowered activity of both Complex I and cytochrome c oxidase in the mutant is due to decreased levels of their mitochondrially encoded subunits.
 ...
PMID:A novel mutation selectively decreases complex I and cytochrome c oxidase subunits in Chinese hamster mitochondria. 608 29

The effect of p-toluyl m-nitro-piperazine on energy conservation processes in rat liver mitochondria is presented. The drug showed an inhibitory effect on the three segments of the respiratory chain and on the ATPase system. NADH oxidase and NADH dehydrogenase activity was inhibited 100%. The velocity and amplitude of swelling induced by glutamate, succinate, ascorbate + TMPD, and ATP was significantly changed by p-toluyl m-nitro-piperazine. It was suggested that the general action of the drug on mitochondrial metabolism would be concerning with modifications on mitochondrial membrane.
 ...
PMID:Possible mechanism of action of piperazine derivatives on liver mitochondria. I--Effect of p-toluyl m-nitro-piperazine (p-TNP). 627 80

Ischemic myocardium was produced by occluding the left circumflex coronary artery in anesthetized dogs. Autolyzed myocardium was produced by incubating transmural samples of canine left ventricle at 37 degrees C. Tissue pH was recorded continuously in each model using a microcombination pH electrode impaled into the midmyocardium. The activities of the five mitochondrial inner membrane enzyme complexes of electron transport and coupled oxidative phosphorylation were assayed as a function of time of ischemia or autolysis. While the activities of complex II (succinate-CoQ reductase) and IV (cytochrome c oxidase) were completely stable, that of complex I (NADH-CoQ reductase) decreased markedly, but largely only after 20 min of ischemia or autolysis. At 20 min and beyond, the decrease in the activity of complex I paralleled closely the decrease in whole mitochondrial oxygen uptake with NAD-linked substrates in both models. The activity of complex III (CoQH2-c reductase) decreased at a more gradual rate during ischemia or autolysis, and its rate of decrease paralleled that of succinate-supported oxygen uptake. The activity of complex V (oligomycin-sensitive ATPase) decreased most rapidly (by 40% in only 5 min of autolysis) but nearly leveled off beyond 20 min in the two models. A strikingly similar pattern of differential enzyme lability was observed in isolated control mitochondria incubated at lowered pH values. The results demonstrate 1) differential enzyme lability within the mitochondrial inner membrane, 2) a connection between severity of acidosis and the degree of enzyme activity loss, and 3) the usefulness of simple tissue autolysis as an analogue of in situ myocardial ischemia.
 ...
PMID:Mitochondrial complexes I, II, III, IV, and V in myocardial ischemia and autolysis. 630 12

Cells of Streptococcus mitis ATCC 903 were converted to stable protoplasts by the cell wall-degrading M-1 enzyme of the mutanolysin complex isolated from Streptomyces globisporus. Over 90% of total glucokinase (EC 2.7.1.2), aminopeptidase (EC 3.4.11.1), and dextranglucosidase (EC 3.2.1.70) was recovered in the cytoplasmic fraction, whereas over 20% of total invertase (beta-fructofuranosidase: EC 3.2.1.26) was released during protoplast formation. ATPase (EC 3.6.1.3). chymotrypsin-like protease (EC 3.4.21.1), arginine aminopeptidase (EC 3.4.11.6), and lactate dehydrogenase (EC 1.1.1.27) were detected in Triton X-100 extracts of the cytoplasmic membrane fraction by crossed immunoelectrophoresis in combination with enzyme-staining procedures. By these methods, NADH dehydrogenase (EC 1.6.99.3), aminopeptidase, and lactate dehydrogenase were detected in the cytoplasmic fraction. Aminopeptidases in the cytoplasmic fraction differed from this activity in the membrane fractions in electrophoretic mobility and substrate specificity.
 ...
PMID:Protoplast formation and localization of enzymes in Streptococcus mitis. 634 41

Ca2+-dependent K+ transport and plasma membrane NADH dehydrogenase activities have been studied in several 'high-K+' (human, rabbit and guinea pig) and 'low-K+' (dog, cat and sheep) erythrocytes. All the species except sheep showed Ca2+-dependent K+ transport. NADH-ferricyanide reductase was detected in all the species and showed positive correlation with the flavin contents of the membranes. NADH-cytochrome c reductase was very low or absent in dog, sheep and guinea pig membranes. No correlation was found between NADH dehydrogenase and Ca2+-dependent K+ channel activities in the species studied. Nor were any of the above activities correlated with (Na+ + K+)-ATPase activity.
 ...
PMID:Plasma membrane nadh dehydrogenase and Ca2+-dependent potassium transport in erythrocytes of several animal species. 640 2

Sarcoplasmic and myofibrillar proteins of a frog mixed muscle (distal cruralis bundle) were investigated and compared to their fast twitch muscle homologues. Histochemical reactions revealed two populations of fibres in this muscle, differing from fast twitch fibres by the intensity of their myofibrillar ATPase reaction and by their mitochondrial NADH dehydrogenase activity. The distribution of parvalbumins and LDH isoenzymes in the whole muscle showed some features of tonic muscle type. Myosin light chains pattern of cruralis bundle fibres was characterized by the lower proportion of the LC3 subunit. These results confirmed the heterogeneity of this frog muscle and the presence of tonic or intermediate fibres with their typical sarcoplasmic and myofibrillar proteinic composition.
 ...
PMID:Comparison of the sarcoplasmic and myofibrillar proteins of twitch and tonic fibres of frog muscle (Rana esculenta). 644 68

Left anterior descending coronary artery occlusion in anesthetized pigs produced a stable transmural ischemia characterized by a rapid and then sustained loss of blood flow and mechanical function. After 2 h of occlusion, mitochondria from the ischemic area exhibited a 36 +/- 6% drop in state 3 respiratory activity (QO2) supported by the NAD-linked substrates, glutamate plus malate, but only a 5 +/- 3% decrease in QO2 with succinate plus rotenone. The activity of electron transfer complex I (NADH-CoQ reductase) decreased commensurately by 33 +/- 4% with the decrease in QO2 with NAD-linked substrates. Consistent with the nearly unchanged QO2 with succinate plus rotenone, the activities of electron transfer complexes III and IV decreased only slightly by 9 +/- 5% and 9 +/- 4%, respectively. Mitochondrial ATPase (complex V) activity decreased by 48 +/- 2% with little change in its oligomycin sensitivity. A 48% drop in ATPase activity was shown, by means of oligomycin titrations, to correspond to a 32% decrease in NAD-linked substrate supported QO2. The decreases observed in NADH-CoQ reductase and ATPase activities each account nearly quantitatively for the impaired mitochondrial phosphorylating respiration observed during sustained myocardial ischemia. These results suggest that mitochondrial inner enzyme complexes I and V are important sites of cellular injury in myocardial ischemia.
 ...
PMID:Mitochondrial inner membrane enzyme defects in porcine myocardial ischemia. 645 Nov 85

Rat liver mitochondria, stored with the energy-linked functions preserved or in aging conditions, were used to assay the activity of various enzymes during five days. The preservation of energy-linked functions was monitored by the respiratory control coefficient. ATPase, cytochrome oxidase and NADH dehydrogenase showed increased activity when the energy-linked functions were preserved. In aging conditions, cytochrome oxidase, NADH dehydrogenase and ATPase showed decreased activity. The ATPase activity increased only when mitochondria were stored in the presence of inhibitors of the electron transport chain. The activity of NADH oxidase did not change, and succinate oxidase and succinate dehydrogenase showed a small decrease in their activity. The enzymes of the matrix, alpha-ketoglutarate dehydrogenase, malate dehydrogenase and aspartate aminotransferase showed little decrease in activity under either of the conditions of storage. The total protein content decreased slightly under both conditions of storage. These results show that the activity of the enzymes analysed was maintained at reasonable levels, when the energy-linked functions of isolated mitochondria were preserved.
 ...
PMID:Studies on rat liver mitochondria: 4. Enzyme activities in mitochondria preserved at 0-4 degrees C. 646 13

Under dark and essentially anaerobic conditions electron flow to either dimethylsulphoxide or trimethylamine-N-oxide in cells of Rhodopseudomonas capsulata has been shown to generate a membrane potential. This conclusion is based on the observation of a red shift in the carotenoid absorption band which is a well characterised indicator of membrane potential in this bacterium. The magnitude of the dimethylsulphoxide- or trimethylamine-N-oxide-dependent membrane potential was reduced either by a protonophore uncoupler of oxidative phosphorylation or synergistically by a combination of a protonophore plus rotenone, an inhibitor of electron flow from NADH dehydrogenase. These findings, together with the observation that venturicidin, an inhibitor of the proton translocating ATPase, did not reduce the membrane potential, show that electron flow to dimethylsulphoxide or trimethylamine-N-oxide is coupled to proton translocation. Thus contrary to some previous proposals dark and anaerobic growth of Rps. capsulata in the presence of dimethylsulphoxide or trimethylamine-N-oxide cannot be regarded as purely fermentative.
 ...
PMID:Electron flow to dimethylsulphoxide or trimethylamine-N-oxide generates a membrane potential in Rhodopseudomonas capsulata. 666 89

The cell wall (CW), cytoplasmic (CM) and intracytoplasmic membrane (ICM) fractions were obtained by sucrose linear gradient centrifugation of membrane preparations of Methylomonas methanica. The CW fraction represented by large open fragments with 5-layer structure is enriched in lipopolysaccharides and is similar in its protein composition to the CW fractions of other gram-negative bacteria. The CM vesicles are surrounded with a unit membrane, have high activities of marker enzymes (NADH dehydrogenase, succinate dehydrogenase and ATPase), a higher phospholipid content, cytochromes of a-, b- and c-types and differ qualitatively in its protein composition from the CW fraction. The ICM fraction has much in common with the CM fraction but differs from it by a higher level of marker enzymes and cytochromes of b and c types.
 ...
PMID:[Isolation and characterization of membranes from Methylomonas methanica]. 733 69


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>