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

---

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

Escherichia coli strains that lacked the d-type cytochrome oxidase, the terminal oxidase with a high affinity for O2, grew anaerobically as well as the wild type did and were not impaired in the ability to evolve H2 from either glucose or formate. The anaerobic synthesis and activity of nitrogenase in transconjugants of these strains carrying Klebsiella pneumoniae nif genes were also normal. However, the behavior towards O2 of anaerobically grown bacteria lacking the d-type oxidase differed from that of the wild type in the following ways: the potential O2 uptake was lower, H2 evolution and nitrogenase activity supported by fermentation were more strongly inhibited by O2, and microaerobic O2-dependent nitrogenase activity in the absence of a fermentable carbon source did not occur. These results show that the d-type oxidase serves two functions in enteric bacteria--to conserve energy under microaerobic conditions and to protect anaerobic processes from inhibition by O2.
...
PMID:Roles for enteric d-type cytochrome oxidase in N2 fixation and microaerobiosis. 215 9

Isolated vegetative tumour cells from mice bearing the Lewis lung carcinoma showed low rates of basal respiration with both low oxygen uptake rates and cytochrome-c oxidase activity. The cells were affected by a marked Crabtree effect and a high rate of lactate production in the presence of 10 mM glucose. The glycolytic capacity of the tumour was also assessed through the measurement of the maximum activities for hexokinase, phosphofructokinase, pyruvate kinase and lactate dehydrogenase. These activities were similar to the ones found in other fast-growing, undifferentiated tumours. The concentration of fructose-2,6-bisphosphate in the tumour was 2,3 nmoles/g fresh tissue wt., a value which is of the same order of magnitude as that found in other types of highly glycolytic cells. It is concluded that the Lewis lung carcinoma follows the same pattern as other undifferentiated tumours with a high capacity for both glucose and amino acid utilization.
...
PMID:The impairment of respiration by glycolysis in the Lewis lung carcinoma. 215 46

The structure of cytochrome oxidase from beef heart mitochondria has been analysed by cryo-electron microscopy of vesicle crystals of the space group p22(1)2(1), with cell dimensions a = 102 A, b = 123 A, gamma = 90 degrees. Several methods of specimen preparation were applied to the vesicular two-dimensional crystals in the electron microscope, to ensure that the structure was preserved to the maximum resolution. The two most informative density maps were from specimens embedded in ice and from negative staining in a 1:1 mixture of glucose and uranyl acetate. The three-dimensional structure of the ice-embedded molecule shows a single, well resolved, but convoluted density, which represents in size and shape one cytochrome oxidase dimer. At the bottom of the molecule, a substantial part of the protein is embedded in the lipid bilayer of the vesicle. The molecule then extends upwards, out of the bilayer, into the internal space within the vesicle. Here, the structure first passes through a region within the molecule containing a hollow cavity that lies roughly at the centre of mass of the dimer, and then branches into two well-resolved halves at some distance from the membrane. The negatively stained structure, in contrast, shows a stain-excluding region in the centre of the vesicle at the level of the cavity in the ice-embedded structure, but otherwise has a similar overall external shape. In addition, there is a small rotation of the whole molecule by approximately 25 degrees relative to the orientation of ice-embedded specimens. We interpret these differences to mean that the central cavity seen in the ice-embedded structure is too small to allow the stain to penetrate during the drying process and that the drying process causes the rotation. The structures described here are consistent with one another and allow an interpretation at higher resolution than from previous work.
...
PMID:Electron cryo-microscopic analysis of crystalline cytochrome oxidase. 216 84

Cultured skin fibroblasts from patients with lacticacidemia were incubated with glucose for 1 h and the lactate and pyruvate production measured. Those patients with increased lactate to pyruvate ratios were further analyzed for the cause of the abnormal redox state. Two categories of patients are described. The first contains patients with either severe or partial cytochrome oxidase deficiency; this group can be broken down further into patients with Leigh's disease, Kearns-Sayre syndrome, and liver-specific cytochrome oxidase deficiency. In this group, the rise in lactate to pyruvate ratio roughly correlated with the severity of the defect. The second patient category had defects located in complex I of the mitochondrial respiratory chain. This is easily demonstrated in the most severely affected patients with the fatal infantile form of the disease. Patients with severe defects in either complex I or cytochrome oxidase had complexes that were only partially assembled. Patients with mitochondrial encephalopathy with lactic acidosis and stroke-like episodes demonstrated only minor changes in redox state and in the behavior of the mitochondrial respiratory chain.
...
PMID:The use of skin fibroblast cultures in the detection of respiratory chain defects in patients with lacticacidemia. 217 27

Klebsiella pneumoniae synthesized only b-type and d-type cytochromes under the wide range of growth conditions tested, and reaction with CO revealed two potential oxidases. The o-type oxidase was produced only in the presence of O2 and appeared to be repressed by glucose. The d-type oxidase was, by contrast, produced only in the absence of measurable O2 (less than 1 microM), and was the only oxidase expressed in nitrogen-fixing conditions. It was extracted from the membrane, purified and shown to be similar to that from E. coli in being a heterodimer (subunits of Mr 52,000 and 35,000), in containing two distinguishable b haems and haem d (one or two molecules per molecule of oxidase), and in being able to react with O2 to give a stable oxygenated intermediate. The purified d-type cytochrome oxidase had a very high affinity for O2 (Km 20 nM; measured by the spectral properties of leghaemoglobin). It is proposed that this provides a role for this oxidase in lowering the O2 concentration to allow nitrogenase synthesis and function, and to provide a terminal oxidase to permit electron-transport-coupled ATP synthesis which supports the increase in efficiency of nitrogen fixation observed under microaerobic conditions.
...
PMID:The purification, characterization and role of the d-type cytochrome oxidase of Klebsiella pneumoniae during nitrogen fixation. 219 Oct 76

The reduction of 2,6-dichlorophenolindophenol (DCIP) was measured by amperometric methods in Morris hepatoma 3924A cells, normal isolated rat hepatocytes and in mitochondria isolated from normal rat liver. The influence of aerobic and anaerobic atmospheres and of various inhibitors of cellular metabolism, especially of the respiratory chain (KCN, NaN3, oligomycin), on DCIP-reduction were studied using glucose, succinate, beta-hydroxybutyrate, alpha-keto-glutarate and oxalacetate as substrates. Under the influence of KCN and oligomycin the velocity of DCIP-reduction was increased in both cell types. Azide showed a similar effect on tumour cells and to a lower extent on hepatocytes. Using isolated mitochondria total DCIPred was increased by KCN and azide using various mitochondrial metabolites as substrates and with ADP/Pi present. The effects of KCN, azide and oligomycin could be explained by taking DCIP as an artificial coupling site in mitochondria which is only used when oxygen is absent or when the respiratory chain is blocked by inhibitors of cytochrome oxidase. Evaluation of the reaction kinetics revealed differences between normal and transformed cells in terms of the pseudo-first-order rate constants and the activity of overall oxidoreductases. The results apparently reflect quantitative differences in enzymatic equipment and the metabolic pathways predominating in normal and neoplastic cells.
...
PMID:Investigation by amperometric methods of intracellular reduction of 2,6-dichlorophenolindophenol in normal and transformed hepatocytes in the presence of different inhibitors of cellular metabolism. 229 12

The steady state levels of mitochondrial rRNAs, 5 tRNAs, the 9 S RNA, and the RNA products from the genes coding for subunits 6 and 9 of the ATP synthase, cytochrome b, and subunit 1 of cytochrome oxidase have been determined after growth of yeast under conditions of respiratory repression or derepression. The analysis indicates that the mitochondrial rRNAs are present in 2000 or 9000 copies/cell in repressed or derepressed yeast, respectively. The levels of the other RNAs also differed to a similar extent, with the exception of the level of the tRNAfMet which differs by only 1.7-fold. The levels of the individual protein coding RNAs varied from 480 copies/cell for the Oli-1 RNA to 100 copies/cell for the Oli-2 RNA under derepressive conditions and from 130 copies/cell to 33 copies/cell for the same RNAs in glucose repressive conditions. The levels of the tRNAs varied even more markedly, ranging from 4200 copies/cell for the tRNAPhe to 240 copies/cell for the tRNACys after growth in derepressive conditions and from 800 copies/cell for the tRNAfMet to 30 copies/cell for the tRNACys of glucose repressed yeast. These results indicate that glucose repression uniformly decreases the levels of the individual mitochondrial RNAs studied. This decrease is related to a lower synthesis of mitochondrial RNA in the glucose repressed cells as compared to derepressed cells.
...
PMID:Steady state analysis of mitochondrial RNA after growth of yeast Saccharomyces cerevisiae under catabolite repression and derepression. 242 12

Histochemical evidence of the activity and distribution of glycolysis redox enzymes, tissue respiration and terminal oxidation pattern (dehydrogenase of lactic, malic, succinic and isocitric acids, NAD-N- and NADPh-N-ase, cytochrome oxidase) as well as the levels of the major carbohydrates (glycogen, neutral aminopolysaccharides, glucose) were experimentally studied in the cardiomyocytes of myocardial necrotic, perinecrotic and intact areas in the control and in the experimental material under the administration of terrilitin-nicotinic acid mixture. It was stated that the use of aforementioned mixture contributed to the retention of enzymatic activity and optimal levels of energy formation in the cardiomyocytes of the marginal infarction zone and noticeably prevented the destructive involvement of the considered area as well as the impairment of functional activity of oscillating cardiomyocytes. Therefore, the application of the mixture improved the outcome prognosis in acute myocardial infarction.
...
PMID:[The structuro-functional state of the ischemic myocardium under the action of a terrilitin-nicotinic acid mixture in animal experiments]. 245 88

The in vitro metabolism of [1-13C]glucose by Ascaris suum third and fourth-stage larvae was analyzed under different gas phases using 13C nuclear magnetic resonance spectroscopy (13C-NMR). Third-stage larvae (L3) incubated under a gas phase of 85% N2/5% O2/10% CO2 produced trace amounts of [13C]succinate, and molted to fourth-stage larvae (L4) between days 3 and 4 in vitro. However, they appeared to arrest as L3s when incubated under air, or 85% N2/5% O2/10% CO2 in the presence of 2 mM potassium cyanide, or 95% N2/5% CO2. Day 12 L4 (eight days after molting) incubated under 85% N2/5% O2/10% CO2, or 95% N2/5% CO2, or 94% N2/1% O2/5% CO2, produced succinate, acetate, propionate and the branched-chain fatty acids 2-methylvalerate and 2-methylbutyrate by fermentative pathways characteristic of adult body wall muscle. In contrast, when Day 12 L4 were incubated under air, only trace amounts of these acids were detected in the incubation medium. Thus, L4 are capable of synthesizing end-products typical of the adult even in the presence of oxygen, as long as the CO2 tensions are above 5%. As would be predicted, activities of enzymes involved in aerobic metabolism, including citrate synthase, isocitrate dehydrogenase, and cytochrome oxidase, decreased dramatically as L4s underwent the final ecdysis and matured to the adult stage. More importantly, activities of enzymes typical of anaerobic metabolism, including phosphoenolpyruvate carboxykinase and malic enzyme, were substantially elevated in L3s (over their levels in second-stage larvae), and appeared to have reached their adult levels in L3s prior to the third molt, even though L3s still exhibited cyanide sensitivity. Since L3s and L4s have enzymes involved in both aerobic and anaerobic pathways, it is possible that the L3s contain two populations of mitochondria, one which functions aerobically and a second which functions anaerobically.
...
PMID:Effect of gas phase on carbohydrate metabolism in Ascaris suum larvae. 250 8

Heart transplantation involves chronic effects due to denervation, rejection, and treatment of rejection. The chronically denervated dog heart provides a model for the effects of denervation alone. These hearts have been shown to contain intrinsic neurons with VIP and NPY as possible neurotransmitters. Myocardial tissue noradrenaline concentration falls to very low levels after degeneration of postganglionic sympathetic neurons, but dopamine remains in near-normal concentration and is probably synthesized extraneuronally. ANP is present and released normally; however, the natriuretic response to atrial distension is blunted, suggesting that this response is mainly due to a reflex mechanism. Chronically denervated myocardial tissue exhibits increased oxygen consumption in vitro and increased Na-K, ATPase activity but has normal tissue levels of ATP and creatine phosphate. Glucose oxidation is inhibited in vivo, associated with increased levels of fructose-6-phosphate but normal glucose-6-phosphate, suggesting inhibition of phosphofructokinase activity. However, the enzyme protein concentration of phosphofructokinase, as judged by maximal in vitro activity, is normal. Maximal in vitro activities of succinate dehydrogenase, cytochrome oxidase, monoamine oxidase, calcium-dependent ATPase, and glyceraldehyde-3-dehydrogenase are also normal. From these findings, we would predict that patients with transplanted hearts are likely to show myocardial metabolic inefficiency.
...
PMID:Cellular abnormalities in chronically denervated myocardium. Implications for the transplanted heart. 253 6


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

---