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)

1. Formate inhibits cytochrome c oxidase activity both in intact mitochondria and submitochondrial particles, and in isolated cytochrome aa3. The inhibition increases with decreasing pH, indicating that HCOOH may be the inhibitory species. 2. Formate induces a blue shift in the absorption spectrum of oxidized cytochrome aa3 (a3 + a33+) and in the half-reduced species (a2 + a33+). Comparison with cyanide-induced spectral shifts, towards the red, indicates that formate and cyanide have opposite effects on the aa3 spectrum, both in the fully oxidized and the half-reduced states. The formate spectra provide a new method of obtaining the difference spectrum of a32+ minus a33+, free of the difficulties with cyanide (which induces marked high leads to low spin spectral shifts in cytochrome a33+) and azide (which induces peak shifts of cytochrome a2+ towards the blue in both alpha- and Soret regions). 3. The rate of formate dissociation from cytochrome a2+ a33+ -HCOOH is faster than its rate of dissociation from a3+ a33+ -HCOOH, especially in the presence of cytochrome c. The Ki for formate inhibition of respiration is a function of the reduction state of the system, varying from 30 mM (100% reduction) to 1 mM (100% oxidation) at pH 7.4, 30 degrees C. 4. Succinate-cytochrome c reductase activity is also inhibited by formate, in a reaction competitive with succinate and dependent on [formate]2. 5. Formate inhibition of ascorbate plus N, N, N', N'-tetramethyl-p-phenylenediamine oxidation by intact rat liver mitochondria is partially released by uncoupler addition. Formate is permeable through the inner mitochondrial membrane and no differences in 'on' or 'off' inhibition rates were observed when intact mitochondria were compared with submitochondrial particles. 6. NADH-cytochrome c reductase activity is unaffected by formate in submitochondrial particles, but mitochondrial oxidation of glutamate plus malate is subject both to terminal inhibition at the cytochrome aa3 level and to a slow extra inhibition by formate following uncoupler addition, indicating a third site of formate action in the intact mitochondrion.
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PMID:The effect of formate on cytochrome aa3 and on electron transport in the intact respiratory chain. 0 41

Pathways of electron transport utilized for respiration in human term placental mitochondrial preparations were differentiated and characterized through the use of classical respiratory chain inhibitors and multiple sources of reducing equivalents. Mechanisms of associated energy conservation and utilization were examined in the preparations with uncouplers and inhibitors of phosphorylation. Inhibition by rotenone, antimycin A and cyanide established the classical electron transport chain as the major pathway of respiration with glutamate and succinate as substrates. Approximately 20% of glutamate-supported respiration was insensitive to inhibitors and may proceed by the cytochrome P-450 linked pathway of electron transport. Approximately 50% of ascorbate-N,N,N',N'-tetramethyl-p-phenylenediamine supported respiration was insensitive to 10-3 M cycanide and must utilize an undefined by-pass of cytochrome oxidase. A rotenone- and antimycin-insensitive, exterior pathway for NADH oxidation was demonstrated which could be artificially linked by exogenous cytochrome c to the cytochrome oxidase region of the classical electron transport system. Glycerol 3-phosphate also supported oxidative phosphorylation yielding ADP/O ratios of 2. Respiration of placental mitochondria was stimulated by 2,4-dinitrophenol and gramicidin. With succinate, dinitrophenol-stimulated respiration exceeded that obtained in the presence of ADP. Oligomycin and atractyloside prevented the stimulation of respiration by ADP. Thus, respiration appeared coupled through normal mechanisms to ATP formation and ion transport. A preferential coupling of respiration to the energy-utilizing processes of steroid hormone biosynthesis may exist.
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PMID:Mitochondria from human term placenta. II. Characterization of respiratory pathways and coupling mechanisms. 4 60

Differentiation and calcification of cartilage of a fracture callus morphologically, ultrastructurally, and histochemically resembles cartilage of growing epiphyseal plate. The fracture callus includes the various cartilage cell types found in the epiphyseal plate. Proliferating and hypertrophic cartilage had higher activities of cytochrome oxidase, alkaline phosphatase and glutamate aspartate transaminase than fibrocartilage. Enzymes controlling glycogen synthesis and glycolysis had higher levels of activity in fibrocartilage than in hypertrophic cartilage. Lysosomal enzymes, catalase, 6-phospho-gluconic acid and glucose 6-phosphate dehydrogenase were uniformly distributed. Alkaline phosphatase was associated with extracellular vesicles found in hypertrophic cartilage. EM dense granules were found in mitochondria in hypertrophic cartilage. There was an increase of total lipids in hypertropic and calcified cartilage as compared to resting cartilage.
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PMID:Morphological and biochemical studies during differentiation and calcification of fracture callus cartilage. 4 43

The object of the study was to investigate the occurrence and localization of oxidative enzymes in the redia -- the third larval stage of Fasciola hepatica L. The author detected cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases (diaphorases), as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate, and alcohol dehydrogenases. The presence and localization of the enzymes in various periods of development of the redia were detected with histochemical methods. Out of the studied oxidases and dehydrogenases only cytochrome oxidase was found to be absent from the stages of young rediae. It was ascertained that the redia uses all three paths of release of energy i.e. the glycolytic, Krebs, and pentose cycles, glycolysis being presumably the principal mode of energy production.
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PMID:Oxidative enzymes in the development of Fasciola hepatica L. IV. The activity of oxidases and dehydrogenases in redia. 17 35

The object of the study was the investigation of the occurrence and localization of oxidative enzymes in the 4th and 5th larval stages of the liver fluke, i. e. in the cercaria and metacercaria. The following enzymes were detected: cytochrome oxidase, peroxidase, NADH and NADPH tetrazolium reductases/diaphorases) as well as succinate, isocitrate, malate, lactate, alpha-glycerophosphate, glyceraldehyde phosphate, glucose-6-phosphate, 6-phosphogluconate, beta-hydroxybutyrate, L-glutamate and alcohol dehydrogenases. The occurrence and localization of the enzymes were investigated histochemically in the cercaria still unreleased from the snail tissues, in the free natatorial cercaria, and in the encysted specimen, i.e. metacercaria. Among the enzymes studied only peroxidase was found to be absent from the cercaria and metacercaria, the latter larva being deprived of alcohol and L-glutamate dehydrogenases as well. The aerobic path, i.e. the Krebs cycle, was ascertained as the principal mode of obtaining energy in the free natatorial cercaria and metacercaria, and glycolysis as the main energy path for the undetached larva. The analysis of the above-mentioned oxidative enzymes was the basis for the description, within the available range, of the function and metabolism of individual organs of cercaria in different periods of its development. In the recapitulation the author discusses the effect of the parasitic way of life of the larval forms of Fasciola hepatica on their energy metabolism.
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PMID:Oxidative enzymes in the development of Fasciola hepatica L. V. Activity of oxidases and dehydrogenases in the Cercaria and Metacercaria. 17 36

Inorganic lead, added to the diet of suckling rat in high doses, produces an encephalopathy similar to that seen in the immature human. Pathologic changes of edema and hemorrhage are seen earliest and are most prominent in the cerebellum. In this study, we measured respiration in cerebral hemisphere and cerebellar mitochondria isolated from led-fed and age-matched normal rat pups. Lactating mothers were begun on ad libitum feedins containing 4% lead carbonate when their pups were 2 weeks old. Mitochondria were isolated by differential centrifugation. Oxygen consumption was measured polarographically, NAD-linked respiration was measured with oxidation of the substrate pair, glutamate and malate. Cytochrome oxidase (cytochrome c oxidase, EC. 1.9.3.1) activity was measured in the presence of tetramethyl-p-phenylenediamine dihydrochloride (TMPD) and ascorbate. Within 2 days of starting lead feedings, rat pups showed a significant loss in body weight (P less than 0.02) and, after 1 week, a significant loss in cerebral hemisphere wet weight (P less than 0.01) compared with controls. Overt encephalopathy appeared in pups from two of nine litters receiving lead feedings for 1 week and in half of the litters after 2 weeks of feedings. None of the lead-fed mothers developed encephalopathic signs. With oxidation of the NAD-linked substrate pair, there was a progressive decrease, relative to controls, in ADP/O ratios in both cerebellar and cerebral mitochondria from lead-fed animals. After 2 weeks these differences were significant in mitochondria from both regions (cerebellum, P less than 0.02; cerebrum, P less than 0.005). Respiratory control ratios were significantly lower in cerebellar mitochondria from lead-fed rats within 2 days of beginning feedings (P less than 0.02) and in mitochondria from both regions after 2 weeks of lead feedings (cerebellum, P less than 0.01; cerebrum, P less than 0.05). The decrease in control ratios in cerebellar mitochondria from animals receivint lead feedings for 1 week or less was due to a small decrease in state 3 respiration and a large, but inconsistent, increase in state 4 respiration. The decrease in control ratios in both cerebellar and cerebral hemisphere mitochondria after 2 weeks of lead feedings was due to a marked inhibition of state 3 respiration, relative to controls (cerebellum, P less than 0.01; cerebral hemisphers, P less than 0.05). In cerebellar mitochondria from lead-fed animals, cytochrome oxidase activity showed similar changes compared with controls: a highly significant (P less than 0.001) increase within 2 days of beginning feedings and a significant (P less than 0.01) decrease after 2 weeks of feedings.
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PMID:Early effects of inorganic lead on immature rat brain mitochondrial respiration. 17 53

There is only indirect evidence to suggest that the sudden postpartum appearance of dietary lipid regulates the perinatal development of the enzyme pathways required for fatty acid oxidation. To test this idea directly, rabbit pups were maintained on diets containing lipid to equal either 14.2% (LF) or 77.6% (HF) of the total caloric intake. Palmityl coenzyme A oxidation rates in the presence of excess ADP and carnitine were measured polarographically in heart and liver homogenates. No significant difference in oxidation rates between HF and LF groups was observed even at 10 days of age. Palmityl coenzyme A oxidation in both groups was carnitine dependent and was in general the same as that of mother-fed animals. Similarly, an evaluation of cytochrome oxidase activity and glutamate + malate-supported respiration in heart and liver homogenates revealed no difference attributable to diet. To consider the possibility that fatty acid oxidation might be specifically increased or decreased over other mitochondrial respiratory activity as a function of diet, palmityl coenzyme A oxidation rates were normalized with respect to glutamate + malate oxidation rates. A similar comparison was made relative to cytochrome oxidase activity. Still no differences were observed between HF and LF groups. By studying the maximum rate of oxygen utilization in the presence of excess carnitine and palmityl-coenzyme A we would have detected any change in a rate-limiting step for fatty acid oxidation beyond acyl activation. We must conclude, therefore, that large differences in the proportion of postnatal dietary lipid do no influence the cellular capacity to oxidize palmityl coenzyme A.
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PMID:Dietary lipid and postnatal development. II. Palmityl coenzyme A oxidation in heart and liver. 18 52

Subcellular copper distribution was studied after single alimentary loading of rats with copper sulfate and after 2- and 4-day spontaneous decorporation of the metal. Copper content in mitochondria and in the soluble fraction was found to rise as early as the 1st day. Then it decreased reaching the normal values after 2-day and 4-day autodecorporation for cytosol and mitochondria, respectively. The activities of rotenone-sensitive NADH-cytochrome c reductase, succinate-cytochrome c reductase and cytochrome oxidase were inhibited by copper treatment but after a 4-day decorporation they became normal. On the contrary, rotenone-insensitive NADH-cytochrome c reductase was activated. Single alimentary copper treatment induced changes in electron transport and oxidative phosphorylation with succinate and glutamate as substrates. The changes established were in accordance with the decreased enzyme activities. After chronic copper loading (7-8 weeks) the interruption of copper-enriched diet for 5 days led to restoration of the copper content in the subcellular fractions. Treatment with unitiol did not change the spontaneous decorporation.
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PMID:Decorporation of copper from liver subcellular fractions after alimentary loading of rats. 21 32

Redox reactions were studied in 217 placentas obtained after partus maturus and pathological labor (premature labor, gestoses, incompatibility by Rh antigen, uterine inertia, placentas at early therapeutic and spontaneous abortions). Several uniform alterations were observed in activities of NADP-dependent isocitrate dehydrogenase, lactate-, glutamate- and malate dehydrogenases. Increase in the activity of these enzymes was accompanied by alteration in distribution of LDH isoenzymes and by elevated formation of glutamic acid; activities of transaminases, cytochrome c and cytochrome oxidase were unaltered. The alterations observed appear to be due to activation of compensatory-adaptive mechanisms of placenta.
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PMID:[Role of oxidative processes in the realization of the adaptive mechanisms of the human placenta]. 59 4

The dermal cells in grey, xanthic, and white goldfish integuments were cytochemically characterized for the following enzymatic activities: tyrosinase, DOPA-oxidase, cytochrome oxidase, monoamine oxidase, peroxidase, non-specific esterase, cholinesterase, NAD-diaphorase, NADP-diaphorase, aryl sulfatase, nucleotide phosphodiesterase, beta-glucuronidase, acid phosphatase, alkaline phosphatase, adenosine triphosphatase, thiamine pyrophosphatase, glucose-6-phosphatase, aldolase, as well as succinate, malate, isocitrate, glutamate, glucose-6-phosphate, 6-phosphogluconate, alpha-glycerophosphate, alcohol, lactate, and beta-hydroxybutyrate dehydrogenases. It was found that the epidermis was a significant barrier to the access of cytochemical reaction substrates. Removal of the epidermal barrier provided dermal cell localizations of enzymatic activities which were reproducible. Further, alterations in reaction times and temperatures from the mammalian methodology provided conditions fe various integumental cells were compared for possible interrelationships. The basic foundations for future work with the dermis of poikilothermic vertebrates on an experimental basis were established. In addition, a previously undescribed non-pigmented dermal cell, the "x"-cell, was found to have enzymatic characteristics similar to both melanophores and lipophores. The "x"-cell may be the common precursor of both types of pigment cells.
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PMID:Cytochemical characterization of goldfish (Carassius auratus L.) dermis with special reference to the pigment cells. 82 86


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