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:1.9.3.1 (cytochrome oxidase)
8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The maximal rate (Vmax) of some mitochondrial enzymatic activities related to the energy transduction (citrate synthase, malate dehydrogenase, NADH cytochrome c reductase as total, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase) were evaluated in non-synaptic (free) and synaptic mitochondria from rat brain hippocampus. Three types of mitochondria were isolated from rats subjected to single i.m. treatment with L-acetylcarnitine (308 mg X kg-1) or to sub-chronic i.m. treatment with L-acetylcarnitine at three different dose levels (38; 154; 614 mg X kg-1, 5 days a week, for 4 weeks). With respect to the enzymatic pattern of three types of non-synaptic and synaptic mitochondria, in hippocampus a different maximal rate of both total NADH-cytochrome c reductase and cytochrome oxidase was observed, these activities being lower in "synaptic heavy" mitochondrial subfraction rather than that in both "free" and "synaptic light" ones. This confirms that in various types of brain mitochondria a different metabolic machinery exists. Acute treatment with L-acetylcarnitine decreased citrate synthase and glutamate dehydrogenase activities only in mitochondria obtained from synaptosomes. The sub-chronic treatment with L-acetylcarnitine decreased the activity of citrate synthase and total NADH-cytochrome c reductase activities only in the same type of mitochondria, i.e. synaptic mitochondria. Therefore in vivo administration of L-acetylcarnitine mainly affects some specific enzyme activities (suggesting a specific molecular trigger mode of action) of the intrasynaptic mitochondria (suggesting a specific subcellular trigger site of action).
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PMID:Action of L-acetylcarnitine on different cerebral mitochondrial populations from hippocampus. 396 36

The respiratory parameters of a freshwater teleost, Tilapia mossambica Peters, were studied under sublethal intoxication of methyl parathion. The rate of oxygen consumption by whole fish and selected tissues decreased during a 48-hr time-course study. The activities of the respiratory enzymes succinate dehydrogenase, malate dehydrogenase, and cytochrome-c oxidase also decreased considerably under methyl parathion exposure in muscle, gill, liver, and brain tissues. These results suggest that methyl parathion has a profound effect on the oxidative metabolism of the fish which results in low ATP turnover, possibly due to its influence on the respiratory center of the brain.
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PMID:Methyl parathion (O-O-dimethyl O-4-nitrophenyl thiophosphate) effects on whole-body and tissue respiration in the teleost, Tilapia mossambica (Peters). 400 33

Muscular glycolytic fuels, intermediates and end-products (glycogen, glucose, glucose-6-phosphate, pyruvate, lactate), Krebs cycle intermediates (citrate, alpha-ketoglutarate, succinate, malate), related free amino acids (glutamate, alanine), ammonia, energy store (creatine phosphate), energy mediators (ATP, ADP, AMP) and energy charge potential were evaluated. Furthermore the maximum rate (Vmax) of the following muscular enzyme activities was evaluated in the crude extract and/or mitochondrial fraction: for the anaerobic glycolytic pathway: hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase; for the tricarboxylic acid cycle: citrate synthase, malate dehydrogenase; for the electron transfer chain: total NADH cytochrome c reductase, cytochrome oxidase. The rat gastrocnemius muscles were analyzed in normoxia and after repeated, alternate hypoxic and normoxic exposures (12 hours of hypoxia daily; for 5 days). Naftidrofuryl was administered daily at three different doses: 10, 15 and 22.5 mg/kg i.m., 30 min before the beginning of the experimental hypoxia. The biochemical adaptation to intermittent normobaric hypoxic-normoxic exposures was characterized by the decrease of the muscular contents of creatine phosphate, citrate, alpha-ketoglutarate and glutamate. This adaptation occurred in absence of significant changes in the Vmax of the muscle enzymes tested. By naftidrofuryl treatment, in gastrocnemius muscle from hypoxic rats both alpha-ketoglutarate and creatine phosphate contents maintained normal values, while glutamate concentration remained reduced to subnormal values. With the exception of hexokinase, naftidrofuryl treatment did not modify the Vmax of marker enzymes related to energy transduction.
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PMID:Adaptation of skeletal muscle energy metabolism to repeated hypoxic-normoxic exposures and drug treatment. 401 59

Muscular glycolytic fuels, intermediates and end-products (glycogen, glucose, glucose-6-phosphate, pyruvate, lactate), Krebs cycle intermediates (citrate, alpha-ketoglutarate, succinate, malate), related free amino acids (glutamate, alanine), ammonia, energy store (creatine phosphate), energy mediators (ATP, ADP, AMP) and energy charge potential were evaluated. Furthermore the maximum rate (Vmax) of the following enzyme activities was evaluated in the crude extract and/or mitochondrial fraction: for the anaerobic glycolytic pathway: hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase; for the tricarboxylic acid cycle: citrate synthase, malate dehydrogenase; for the electron transfer chain: total NADH cytochrome c reductase, cytochrome oxidase. The rat gastrocnemius muscles were analysed in normoxia and after normobaric intermittent hypoxia (12 hours continuously daily; for 5 days). Cytidine and/or uridine were administered daily at the dose of 120 mg/kg, i.p., 30 min before the beginning of the experimental hypoxia. The intermittent normobaric hypoxia induced a biochemical adaptation characterized by the decrease of the muscular contents of creatine phosphate, citrate, alpha-ketoglutarate and glutamate. This adaptation occurred in the absence of significant changes in the Vmax of the tested muscle enzymes. In gastrocnemius muscle from hypoxic rats, the two biological pyrimidines tested induced various discrete, but often related, modifications of the contents of some Krebs cycle intermediates (i.e., alpha-ketoglutarate, malate) and related free amino acids (i.e., glutamate, alanine). In any case, the treatment with cytidine and/or uridine did not modify the Vmax of marker enzymes related to energy transduction.
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PMID:Modification of the skeletal muscle energy metabolism induced by intermittent normobaric hypoxia and treatment with biological pyrimidines. 402 89

Controlled osmotic lysis (water-washing) of rat liver mitochondria results in a mixed population of small vesicles derived mainly from the outer mitochondrial membrane and of larger bodies containing a few cristae derived from the inner membrane. These elements have been separated on Ficoll and sucrose gradients. The small vesicles were rich in monoamine oxidase, and the large bodies were rich in cytochrome oxidase. Separation of the inner and outer membranes has also been accomplished by treating mitochondria with digitonin in an isotonic medium and fractionating the treated mitochondria by differential centrifugation. Treatment with low digitonin concentrations released monoamine oxidase activity from low speed mitochondrial pellets, and this release of enzymatic activity was correlated with the loss of the outer membrane as seen in the electron microscope. The low speed mitochondrial pellet contained most of the cytochrome oxidase and malate dehydrogenase activities of the intact mitochondria, while the monoamine oxidase activity could be recovered in the form of small vesicles by high speed centrifugation of the low speed supernatant. The results indicate that monoamine oxidase is found only in the outer mitochondrial membrane and that cytochrome oxidase is found only in the inner membrane. Digitonin treatment released more monoamine oxidase than cytochrome oxidase from sonic particles, thus indicating that digitonin preferentially degrades the outer mitochondrial membrane.
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PMID:The submitochondrial localization of monoamine oxidase. An enzymatic marker for the outer membrane of rat liver mitochondria. 429 12

1. Mitochondria isolated from livers of fed adult, starved adult, and embryonic rats can be separated into three distinct bands by isopycnic density centrifugation on a sucrose density gradient. The least dense band (B1) has a mean buoyant density of 1.162 and consists mainly of disrupted mitochondria. The middle band (B2) has a mean buoyant density of 1.184. The most dense band (B3) has a mean buoyant density of 1.216. B2 and B3 consist of intact mitochondria. 2. The mitochondria in B2 and B3 have very similar protein/phospholipid ratios, virtually identical phospholipid and fatty acid compositions and similar specific activities for cytochrome oxidase, malate dehydrogenase and monoamine oxidase. Both fractions have very low glucose 6-phosphatase and acid phosphatase activities. 3. As isolated, adult rat liver mitochondria have electron-dense matrices (condensed forms); some embryonic liver mitochondria are condensed, but a significant proportion have dilated matrices. All B2 mitochondria are in the condensed form. B3 mitochondria from adult rats are condensed if fixed in their equilibrium-density sucrose, but when this is diluted rapidly to 0.25m they become swollen. Some B3 mitochondria from embryonic rats are condensed, the others have dilated matrices. They all swell if rapidly diluted to 0.25m-sucrose. B2 mitochondria retain their condensed form on dilution of the sucrose. 4. It is concluded that the matrix space of B2 mitochondria is almost totally inaccessible to sucrose, but that of B3 mitochondria is readily accessible to sucrose. 5. In liver from normally fed adult rats the B2 mitochondria predominate, whereas in starved rats B2 and B3 are present in approximately equal proportions. Mitochondrial preparations from embryonic liver consist predominantly of B3 mitochondria, but the proportion of these decreases progressively as development proceeds. 6. The B2 mitochondria from livers of fed adult rats can be converted into B3 mitochondria by incubation with 10mm-succinate and 10mm-phosphate. 7. Some B2 mitochondria are converted into B3 mitochondria by exposure to high concentrations of sucrose.
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PMID:The isolation by isopycnic density-gradient centrifugation of two mitochondrial populations from livers of embryonic and fed and starved adult rats. 431 15

The isolation of a new class of mutants permitting facultative anaerobiosis in Neurospora crassa is described. Backcross analyses to the obligate aerobe prototroph (An(-)) indicate single nuclear gene inheritance (An(-)/An(+)). An(+) and An(-) are indistinguishable in morphology and growth rates under aerobic conditions. Anaerobic growth requires nutritional supplements that are dispensable for aerobic growth. Conidiogenesis, conidial germination, and vegetative growth rate are suppressed by anaerobiosis. An(+) mutants produce substantial quantities of ethanol under anaerobic conditions. Anaerobiosis and chloramphenicol both affect mitochondrial enzyme activity and morphology. Chloramphenicol inhibition leads to reduction in cytochrome oxidase and swollen mitochondria with few cristae. Anaerobiosis leads to reduction in both cytochrome oxidase and malate dehydrogenase activities, enlarged mitochondria with fewer cristae, enlarged nuclei, and other alterations in cellular morphology. The fine structure of anaerobically grown cells changes with the time of anaerobic growth. We conclude that either inhibition of mitochondrial membrane synthesis or inhibition of respiration might lead to the observed alterations in mitochondria.
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PMID:Mitochondrial biogenesis in Neurospora crassa. I. An ultrastructural and biochemical investigation of the effects of anaerobiosis and chloramphenicol inhibition. 432 55

The present study demonstrates the importance of mitochondrial activities in controlling Mucor rouxii morphogenesis. The respiratory capacity of the spores of this facultatively anaerobic, dimorphic fungus becomes repressed if germination and growth take place in the absence of oxygen. The level of activity of mitochondrial enzymes such as cytochrome oxidase and malate dehydrogenase is lower in the anaerobic yeastlike cells than it is in ungerminated spores and in aerobic hyphae, but the reverse is true for glycolytic enzymes such as pyruvate kinase and alcohol dehydrogenase. Following exposure to air, yeastlike cells convert into hyphae after a lag period corresponding to aerobic adaptation. Anaerobic cultures grown in the presence of ethylenediaminetetraacetate (EDTA) at a concentration of 10(-4) M exhibit hyphal morphology. These cells, which are fully adapted to anaerobic fermentation, nevertheless have potentially active mitochondria with the same levels of respiratory enzymes as ungerminated spores. These cells are able to grow immediately after aeration, without an adaptation lag. Evidence is presented which indicates that the morphogenetic effect of EDTA is not the result of elimination of free metals. Additional evidence proving mitochondrial control of morphogenesis in M. rouxii is that chloramphenicol (4 mg/ml) induced the formation of respiratory-deficient, yeastlike cells in aerobic cultures.
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PMID:Effects of ethylenediaminetetraacetate and chloramphenicol on mitochondrial activity and morphogenesis in Mucor rouxii. 435 71

Mitochondria, released from yeast spheroplasts and subjected to rate separation through sorbitol gradients in the zonal centrifuge, migrated in a wide symmetrical zone. Electron micrographs showed that the mitochondria had been resolved within the zone according to size. The mean mitochondrial diameter at the leading edge was approximately twice that at the trailing edge of the particle zone. Activities of the enzymes cytochrome oxidase, malate dehydrogenase, and reduced nicotinamide adenine dinucleotide- and d-lactate cytochrome c reductases were essentially uniform throughout the mitochondrial zone. Mitochondria from a vegetative-petite mutant had almost the same size distribution as the isogenic wild type, but with somewhat larger mean diameter and either absent or markedly reduced enzyme activities. Mixtures of wild-type and petite mitochondria produced sedimentation profiles showing overlap of particle populations with respect to mean sedimentation rates and mitochondrial diameters, as well as intermediate levels of enzyme activities. Both cristate and noncristate organelles were present throughout the mitochondrial zone from these mixtures. Mitochondria centrifuged in sorbitol density gradients were well-preserved and yielded consistent sedimentation profiles, whereas particles in sucrose density gradients migrated more slowly, produced varied sedimentation profiles, and often showed spurious peaks, presumably due to particle aggregations.
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PMID:Size-separation of yeast mitochondria in the zonal centrifuge. 535 8

Leaves of 10 plant species, 7 with photorespiration (spinach, sunflower, tobacco, pea, wheat, bean, and Swiss chard) and 3 without photorespiration (corn, sugarcane, and pigweed), were surveyed for peroxisomes. The distribution pattern for glycolate oxidase, glyoxylate reductase, catalase, and part of the malate dehydrogenase indicated that these enzymes exist together in this organelle. The peroxisomes were isolated at the interface between layers of 1.8 to 2.3 m sucrose by isopycnic nonlinear sucrose density gradient centrifugation or in 1.95 m sucrose on a linear gradient. Chloroplasts, located by chlorophyll, and mitochondria by cytochrome c oxidase, were in 1.3 to 1.8 m sucrose. In leaf homogenates from the first 7 species with photorespiration, glycolate oxidase activity ranged from 0.5 to 1.5 mumoles x min(-1) x g(-1) wet weight or a specific activity of 0.02 to 0.05 mumole x min(-1) x mg(-1) protein. Glyoxylate reductase activity was comparable with glycolate oxidase. Catalase activity in the homogenates ranged from 4000 to 12,000 mumoles x min(-1) x g(-1) wet weight or 90 to 300 mumoles x min(-1) x mg(-1) protein. Specific activities of malate dehydrogenase and cytochrome oxidase are also reported. In contrast, homogenates of corn and sugarcane leaves, without photorespiration, had 2 to 5% as much glycolate oxidase, glyoxylate reductase, and catalase activity. These amounts of activity, though lower than in plants with photorespiration, are, nevertheless, substantial. Peroxisomes were detected in leaf homogenates of all plants tested; however, significant yields were obtained only from the first 5 species mentioned above. From spinach and sunflower leaves, a maximum of about 50% of the marker enzyme activities was found to be in these microbodies after homogenization. The specific activity for peroxisomal glycolate oxidase and glyoxylate reductase was about 1 mumole x min(-1) x mg(-1) protein; for catalase. 8000 mumoles x min(-1) x mg(-1) protein, and for malate dehydrogenase, 40 mumoles x min(-1) x mg(-1) protein. Only small to trace amounts of marker enzymes for leaf peroxisomes were recovered on the sucrose gradients from the last 5 species of plants. Bean leaves, with photorespiration, had large amounts of these enzymes (0.57 mumole of glycolate oxidase x min(-1) x g(-1) tissue) in the soluble fraction, but only traces of activity in the peroxisomal fraction. Low peroxisome recovery from certain plants was attributed to particle fragility or loss of protein as well as to small numbers of particles in such plants as corn and sugarcane. Homogenates of pigweed leaves (no photorespiration) contained from one-third to one-half the activity of the glycolate pathway enzymes as found in comparable preparations from spinach leaves which exhibit photorespiration. However, only traces of peroxisomal enzymes were separated by sucrose gradient centrifugation of particles from pigweed. Data from pigweed on the absence of photorespiration yet abundance of enzymes associated with glycolate metabolism is inconsistent with current hypotheses about the mechanism of photorespiration. Most of the catalase and part of the malate dehydrogenase activity was located in the peroxisomes. Contrary to previous reports, the chloroplast fractions from plants with photo-respiration did not contain a concentration of these 2 enzymes, after removal of peroxisomes by isopycnic sucrose gradient centrifugation.
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PMID:A survey of plants for leaf peroxisomes. 577 48


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