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:1.6.5.3 (complex I)
8,901 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. Measurements were made at 12 degrees K of the electron-paramagnetic-resonance (e.p.r.) spectra of submitochondrial particles from Candida utilis cells grown under conditions that alter the amount of the mitochondrial NADH dehydrogenase (EC 1.6.99.3). 2. Iron-limited growth decreases the extent of iron-sulphur e.p.r. signals to undetectable values that are less than 1 percent of those normally found with glycerol-limited growth. 3. Small but significant signals attributable to the NADH dehydrogenase were detected in submitochondrial particles from sulphate-limited cells. 4. Measurements made on submitochondrial particles prepared from these and other phenotypically modified cells lead us to conclude that the presence of low-temperature e.p.r.-detectable iron-sulphur centres attributable to the NADH dehydrogenase are necessary but not sufficient for the coupling of ATP synthesis to the NADH dehydrogenase reaction in the mitochondrial membrane of C. utilis. 6. The amplitude of the g=2.01 signal observed in non-reduced submitochondrial particles is approximately tenfold diminished by iron limitation but not significantly altered by sulphate limitation.
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PMID:Electron-paramagnetic-resonance spectroscopy studies of iron-sulphur centres of submitochondrial particles from iron- and sulphur-deficient. Candida utilis. 16 15

The effect of treating mitochondria with visible light above 400 nm on electron transport and coupled reactions was examined. The temporal sequence of changes was: stimulation of respiration coupled to ATP synthesis, a decline in ATP synthesis, inactivation of respiration, increased ATPase activity and, later, loss of the membrane potential. Loss of respiration was principally due to inactivation of dehydrogenases. Of the components of dehydrogenase systems, flavins and quinones were most susceptible to illumination, the iron-sulfur centers were remarkably resistant to being damaged. Succinate dehydrogenase was inactivated before choline and NADH dehydrogenase. Redox reactions of cytochromes and cytochrome c oxidase activity were unaffected. Inactivation was O2-dependent and prevented by anaerobiosis or the presence of substrates for the dehydrogenases. Light in the range 400-500 nm was most effective and the presence of free flavins greatly enhanced inactivation of all of the above mitochondrial activities. This suggests that visible light mediates a flavin-photosensitized reaction that initiates damage involving participation of an activated species of oxygen in the damage propagation.
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PMID:Damage to mitochondrial electron transport and energy coupling by visible light. 65 6

Treating bovine epididymal spermatozoa with rutamycin or rotenone inhibited both respiration and motility supported by endogenous substrates. When oxidative phosphorylation had been blocked with various inhibitors, pyruvate was metabolized to yield ATP and restored motility. Fructose, which is metabolized via glycolysis to yield ATP, was also able to resuscitate the cells. Other substrates tested (lactate, acetate, alpha-ketoglutarate, or glyoxylate) were unable to restore motility in rutamycin-treated cells. In the presence of pyruvate, the phosphorylation uncoupler, carbonylcyanide-p-trifluoromethyoxphenylhydrazone, reduced motility and ATP to common levels in untreated cells or cells treated with rutamycin or rotenone. Pyruvate is thus metabolized to produce ATP by a pathway independent of oxidative phosphorylation associated with the electron transport chain. 5-Methoxyindole-2-carboxylic acid, an inhibitor of lipoyldehydrogenase, prevented the increase of motility and ATP in rutamycin-treated cells, indicating that alpha-keto acid oxidation is involved in the production of ATP from pyruvate when rutamycin is present. With pyruvate present, bongkrekic acid, antimycin A, and anaerobiosis eliminated motility, reduced ATP to low levels, and also significantly reduced the rate of pyruvate metabolism. Acetate was produced from pyruvate only when cellular ATP concentrations were low. Decreases in free carnitine concentrations showed that pyruvate initially used was converted to acetylcarnitine. The results indicate that the intramitochondrial lactate dehydrogenase X, which is unique to spermatozoa, allows the NADH resulting from pyruvate oxidation to reduce other pyruvate molecules to lactate. Pyruvate thus competes with, and can substitute for, the NADH dehydrogenase of the electron transport chain. Pyruvate rapidly repletes the acetylcarnitine pool under a variety of conditions.
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PMID:Pyruvate metabolism in bovine epididymal spermatozoa. 83 18

The effects of halothane on the beating response of rat heart cells in tissue culture were studied using an optical-electronic monitoring device. A dose-response curve was obtained over a concentration range to as much as 5 vol per cent halothane. The clinical dosage of 1 vol per cent halothane decreased the inotropic response of 4-10-day-old cells to 59 plus or minus 10 per cent of the original beating strength; no significant decrease in beating strength was seen in 25-30-day-old cells. One volume per cent halothane caused no significant change in the chronotropic response of the heart cells. Higher concentrations of halothane caused significant negative chronotropic and negative inotropic responses in a dose-related manner. When glycolysis was inhibited by 2-deoxyglucose in the growth medium, the cells became dependent on fatty-acid oxidation and oxidative phorphorylation for energy and showed increased sensitivity to halothane; for example, the chronotropic response to 5-8-day old cells treated with 2-deoxyglucose was decreased approximately 70 per cent by exposure to 3 vol per cent halothane, whereas 4-10-day-old cells maintained on a complete growth medium showed only a 40 per cent decrease. Increasing concentrations of halothane decreased the rate of ATP turnover. This supports evidence suggesting that halothane blocks electron transport in the NADH-coenzyme Q reductase level. The model described provides a means for determining anesthetic potency in a mammalian system in terms of functional as well as metabolic responses. It also provides a means for study of metabolic effects of anesthetics and other drugs.
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PMID:Halothane and the beating response and ATP turnover rate of heart cells in tissue culture. 111 60

Idiopathic dilated cardiomyopathy (IDCM) is a primary myocardial disease of unknown cause. We tested the hypothesis that IDCM was associated with a myocardial metabolic defect by determining a comprehensive biochemical profile of metabolite concentrations and enzyme activities for the major metabolic pathways of the myocardium. We used the Doberman pinscher breed as a naturally occurring canine model of IDCM and compared its myocardial profile with that of healthy adult mongrels. Compared with controls, myocardium in IDCM had markedly reduced mitochondrial electron transport activity and myoglobin concentration, in association with acidosis and energy depletion following anoxic challenge: 60% decreased NADH dehydrogenase and 50% decreased ATP synthetase activities; 90% decreased myoglobin concentration; and 30% reduced ATP and 50% increased lactate and proton concentrations. Sarcoplasmic reticulum Ca(2+)-transport ATPase was decreased by 42%. There was a 15% compensatory increase in fatty acid oxidation and Krebs cycle activity. Other biochemical changes were mild by comparison with the mitochondrial defects. We conclude that IDCM is associated with a marked impairment of mitochondrial production of ATP, arising from decreased activity of the mitochondrial electron transport system, including myoglobin. These changes may be secondary to an underlying genetic defect or may indicate a deficiency of the mitochondrial respiratory chain that predisposes this breed to heart failure.
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PMID:Respiratory chain defect of myocardial mitochondria in idiopathic dilated cardiomyopathy of Doberman pinscher dogs. 133 76

The sequence of 13.9 kilobases (kb) of the 17.1-kb mitochondrial genome of Mytilus edulis has been determined, and the arrangement of all genes has been deduced. Mytilus mitochondrial DNA (mtDNA) contains 37 genes, all of which are transcribed from the same DNA strand. The gene content of Mytilus is typically metazoan in that it includes genes for large and small ribosomal RNAs, for a complete set of transfer RNAs and for 12 proteins. The protein genes encode the cytochrome b apoenzyme, cytochrome c oxidase (CO) subunits I-III, NADH dehydrogenase (ND) subunits 1-6 and 4L, and ATP synthetase (ATPase) subunit 6. No gene for ATPase subunit 8 could be found. The reading frames for the ND1, COI, and COIII genes contain long extensions relative to those genes in other metazoan mtDNAs. There are 23 tRNA genes, one more than previously found in any metazoan mtDNA. The additional tRNA appears to specify methionine, making Mytilus mtDNA unique in having two tRNA(Met) genes. Five lengthy unassigned intergenic sequences are present, four of which vary in length from 79 to 119 nucleotides and the largest of which is 1.2 kb. The base compositions of these are unremarkable and do not differ significantly from that of the remainder of the mtDNA. The arrangement of genes in Mytilus mtDNA is remarkably unlike that found in any other known metazoan mtDNA.
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PMID:A novel mitochondrial genome organization for the blue mussel, Mytilus edulis. 138 86

In the cattle filarial parasite, Setaria digitata, the mitochondria-like particles have been shown to possess site I associated oxidative phosphorylation and rotenone sensitive and insensitive pathways for the dehydrogenation of NADH. Quinone depleted mitochondria-like particles show a loss of activity of these NADH dehydrogenases and also a complete loss of fumarate reductase activity. Reconstitution with quinone restores both NADH linked oxygen uptake and fumarate reductase activity. Thus activities of complex I and fumarate reductase are linked to quinone. Hence an inhibitor at the level of quinone can simultaneously block both aerobic and anaerobic pathways which drive ATP production and may prove useful in the effective control of filariasis.
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PMID:Quinone dependent NADH dehydrogenation in mitochondria-like particles from Setaria digitata, a filarial parasite. 149 58

Citrinin depresses the phosphorylation efficiency of rat renal cortical mitochondria, as inferred from the decrease of the respiratory control coefficient (RC) and ADP/O ratios. The transmembrane potential (delta psi) developed by energized mitochondria and the depolarization upon ADP addition are also decreased. Citrinin (1.0 mM) inhibits almost all enzymes linked to the respiratory chain and increases the activity of succinate cytochrome c reductase and succinate oxidase (coupled). Malate and glutamate dehydrogenases are also inhibited. The inhibitory action of citrinin on phosphorylation efficiency could be related to the following findings: the effect on complex I; the action on the ATP synthetase complex; the partial inhibition of the transmembrane potential.
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PMID:Mechanism of citrinin-induced dysfunction of mitochondria. I. Effects on respiration, enzyme activities and membrane potential of renal cortical mitochondria. 155 79

In the cattle filarial parasite Setaria digitata the mitochondria like particles have been shown to possess NADH dependent fumarate reduction coupled with site I electron transport associated phosphorylation. This reduction is catalysed by the fumarate reductase system. The Km for fumarate is 1.47 mM and that for NADH is 0.33 mM. This activity is sensitive to rotenone, antimycin A and o-Hydroxy diphenyl. One ATP is produced for each pair of electrons transferred to fumarate. The fumarate reductase system consisting of NADH-coenzyme Q reductase, cytochrome b like component(s) and succinate dehydrogenase/fumarate reductase is thus very important and hence specific inhibitors of the system may prove useful in the effective control of filariasis.
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PMID:Fumarate reductase system of filarial parasite Setaria digitata. 156 48

Manganese is known to accumulate in mitochondria and in mitochondria-rich tissues in vivo. Although Ca2+ enhances mitochondrial Mn2+ uptake, ATP-bound Mn2+ is not sequestered by suspended rat brain mitochondria, and ATP binds Mn2+ even more tightly than it binds Mg2+. Physiological levels of the polyamine spermine enhanced 54 Mn2+ uptake at the low [Ca2+]s characteristic of unstimulated cells (approximately 100 nM). With succinate as substrate, Mn2+ inhibited oxygen consumption by suspensions of rat liver mitochondria after the addition of ADP but not after the addition of uncoupler. With glutamate/malate as substrate, Mn2+ inhibited ADP-stimulated respiration and also slightly inhibited uncoupler-stimulated respiration. State 4 (resting) respiration was unchanged in all cases, indicating that the inner membrane retained its impermeability to protons. These results suggest that Mn2+ was not oxidized and that it can interfere directly with oxidative phosphorylation, most likely by binding to the F1 ATPase. Mn2+ may also bind to the NADH dehydrogenase complex, but not strongly enough to affect electron transport in vivo. It is suggested that accumulation of manganese within the mitochondria of globus pallidus may help explain the distinctive pathology of manganism.
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PMID:Mn2+ sequestration by mitochondria and inhibition of oxidative phosphorylation. 163 87


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