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)

A histochemical study of the metabolism of rat renal arteries and arterioles. Rat renal arteries and arterioles were examined histochemically to determine their metabolic profiles. Succinate, malate and NAD-isocitrate dehydrogenase, cytochrome oxidase and ubiquinone were assessed to determine aerobic metabolism. Glucose-6-phosphate dehydrogenase and DPN diaphorase were evaluated to determine hexose-monophosphate-shunt activity. Anaerobic metabolism was evaluated via lactate dehydrogenase, and the substrate, glycogen. Gomori's lipase, beta-hydroxybutyrate dehydrogenase and amounts of neutral fat and free fatty acids were assessed as indicators of lipid utilization. Myosin ATPase activity was evaluated as an index of ATP utilization for contraction. Deoxyribonucleic and ribonucleic acids were appraised as indicators of protein synthesis. In general, the oxidative enzymes and myosin ATPase demonstrate considerable activity in renal arteries and arterioles which suggests aerobic metabolism and ATP usage. Renal arteries and arterioles also appear capable of anaerobic metabolism as indicated by strong lactate dehydrogenase reactivity and by the presence of slight to moderate quantities of glycogen, while high levels of glucose-6-phosphate dehydrogenase and moderate amounts of deoxyribonucleic acid suggest a potential for beta-hydroxybutyrate dehydrogenase, minimal lipase activity, and the absence of fatty acids with substantial amounts of neutral fat, indicate limited lipid catabolism.
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PMID:A histochemical study of the metabolism of rat renal arteries and arterioles. 620 11

Crossed immunoelectrophoresis was used to analyze the components of membrane vesicles of anaerobically grown Escherichia coli. The number of precipitation lines in the crossed immunoelectrophoresis patterns of membrane vesicles isolated from E. coli grown anaerobically on glucose plus nitrate and on glycerol plus fumarate were 83 and 70, respectively. Zymogram staining techniques were used to identify immunoprecipitates corresponding to nitrate reductase, formate dehydrogenase, fumarate reductase, and glycerol-3-phosphate dehydrogenase in crossed immunoelectrophoresis reference patterns. The identification of fumarate reductase by its succinate oxidizing activity was confirmed with purified enzyme and with mutants lacking or overproducing this enzyme. In addition, precipitation lines were found for hydrogenase, cytochrome oxidase, the membrane-bound ATPase, and the dehydrogenases for succinate, malate, dihydroorotate, D-lactate, 6-phosphogluconate, and NADH. Adsorption experiments with intact and solubilized membrane vesicles showed that fumarate reductase, hydrogenase, glycerol-3-phosphate dehydrogenase, nitrate reductase, and ATPase are located at the inner surface of the cytoplasmic membrane; on the other hand, the results suggest that formate dehydrogenase is a transmembrane protein.
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PMID:Identification and localization of enzymes of the fumarate reductase and nitrate respiration systems of escherichia coli by crossed immunoelectrophoresis. 621 54

1. Two oligomycin-resistant strains of Saccharomyces cerevisiae have been isolated and shown to have mutations in the oli2 region of the mitochondrial DNA. On solid media containing a non-fermentable energy source, the mutant strains were able to grow only slowly at 28 degrees C and not at all at 18 degrees C or 36 degrees C. 2. When grown in a glucose-limited chemostat at 28 degrees C, the mutant strains were almost completely defective in oxidative metabolism. The mutant mitochondria contained significant levels of all respiratory enzymes, and an active, oligomycin-sensitive ATPase, but the ATP-32Pi exchange activity and P : O ratio were very low. 3. The mutations in these strains are genetically closely linked to mit mutations which have been shown to affect a 20 000-dalton ATPase subunit (Roberts, H., Choo, W.M., Murphy, M., Marzuki, S., Lukins, H.B. and Linnane, A.W. (1979) FEBS Lett. 108, 501-504). Since the mitochondrial ATPase in these mutant strains appears to be fully assembled, the defect in the coupling mechanism is probably a result of a small alteration in the structure of the 20 000-dalton ATPase subunit. 4. When the mutant strains were grown at 18 degrees C, the mitochondria had very low cytochrome oxidase activities, and reduced levels of cytochrome aa3. The largest subunit (Mr 40 000) of this enzyme was not synthesized.
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PMID:Biogenesis of mitochondria. oli2 Mutations affecting the coupling of oxidation to phosphorylation in Saccharomyces cerevisiae. 625 66

Yeast cells growing synchronously in glucose medium accumulate in the cytosol, the cytosolically made subunits of cytochrome oxidase, during the G1 and early-S phases. The mitochondrially made subunits, on the other hand, are detected only after the mid-S phase. The cytosolically synthesized subunits are integrated into the membrane after the mid-S phase.
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PMID:Synthesis and assembly of cytochrome c oxidase in synchronous cultures of yeast. 627 Nov 85

We have analyzed the catabolite regulation of cytochrome oxidase by assaying changes in the synthesis of precursors of the nuclear-coded peptides (IV--VII) of cytochrome c oxidase in an in vitro reticulocyte cell-free system programmed with RNA isolated from cells grown in either glucose or raffinose. As a first step, we have characterized antibodies which bind to the precursors of subunits V and VI. Initial translation products for subunits IV and VII have also been tentatively identified by utilizing these antibodies. The messenger RNAs coding for the precursors of the nuclear-coded subunits fall in the expected size range of 8--15 S. Catabolite repression of the nuclear-coded oxidase peptides appears to be regulated by the abundance of their messenger RNAs. Translation of messenger RNA isolated from yeast cells grown on glucose indicates a coordinate and uniform increase in precursor synthesis during glucose derepression. In contrast, when RNA isolated from raffinose (derepressed) grown cells is used to direct cell-free translation, precursor abundance is high throughout growth, although the synthesis of some of the species changes in a complex pattern of ratio and abundance. These data indicate that the abundance of the messengers for the nuclear-coded precursors is regulated in a fashion dependent on the physiologic state of the cell.
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PMID:Regulation of the nuclear-coded peptides of yeast cytochrome c oxidase. 628 Jul 49

We have used 2-deoxy-D-[14C]glucose (2-DG) autoradiography and cytochrome oxidase histochemistry to examine background and stimulus-induced patterns of metabolic activity in monkey striate cortex. In squirrel monkeys (Saimiri sciureus) that binocularly or monocularly viewed diffuse white light or binocularly viewed bars of many orientations and spatial frequencies, 2-DG consumption was not uniform across the cortex but consisted of regularly spaced radial zones of high uptake. The zones extended through all laminae except IVc beta and, when viewed tangentially, formed separate patches 500 microns apart. The cytochrome oxidase stain in these animals also revealed patches of high metabolism which coincided with the 2-DG patches. Squirrel monkeys binocularly viewing vertical stripes showed parallel bands of increased 2-DG uptake in the cortex, while the cytochrome label in these animals remained patchy. When monkeys were kept in the dark during 2-DG exposure, 2-DG-labeled patches were not seen but cytochrome oxidase-positive patches remained. In macaque (Macaca nemestrina) monkeys, binocular stimulation with many orientations and spatial frequencies produced radial zones of high 2-DG uptake in layers I to IVa and VI. When viewed tangentially, these zones formed a dots-in-rows pattern with a spacing of 350 X 500 microns; cytochrome oxidase staining produced an identical pattern. Macaca differed from Saimiri in that monocular stimulation labeled alternate rows. These results indicate that there are radial zones of high background metabolism across squirrel and macaque monkey striate cortex. In Saimiri these zones do not appear to be related to an eye dominance system, while in Macaca they do. The presence of these zones of high metabolism may complicate the interpretation of 2-DG autoradiographs that result from specific visual stimuli.
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PMID:Background and stimulus-induced patterns of high metabolic activity in the visual cortex (area 17) of the squirrel and macaque monkey. 629 33

Leucine can be utilized efficiently as a precursor for lipid biosynthesis by adipose tissue, especially in the presence of glucose or glucose and insulin. During the differentiation of 3T3-L1 fibroblasts to adipocytes, the rate of lipid biosynthesis from L-[U-14C]leucine increases at least 30-fold and lipogenesis, with [U-14C] acetate as the precursor, increases by 10- to 15-fold. The specific activities of two mitochondrial dehydrogenases in the leucine oxidative pathway, the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase, as well as of leucine:alpha-ketoglutarate transaminase, increase at least 20-fold during the adipose conversion. Isovaleryl-CoA dehydrogenase was assayed in crude extracts using a specific fluorimetric method employing electron transfer flavoprotein as the electron acceptor for the flavoprotein dehydrogenase. The specific activity of 3-hydroxy-3-methylglutaryl-CoA lyase, the mitochondrial enzyme catalyzing the terminal reaction in the leucine degradation pathway, increases 4-fold during differentiation. The increases in the specific activities of the mitochondrial enzymes occur without a change in the specific activity of cytochrome oxidase, indicating that the increases do not simply reflect proliferation of mitochondria. The biosynthesis of at least 20 soluble mitochondrial polypeptides is enhanced during the adipose conversion of the fibroblasts as determined by polyacrylamide gel electrophoresis following incubation of the cells with [35S] methionine. The results provide a conservative estimate of the extent of changes in mitochondrial soluble proteins during the adipose conversion. They also establish that differentiated 3T3-L1 adipocytes metabolize leucine like mature adipose tissue and illustrate the roles of the branched chain alpha-ketoacid dehydrogenase and isovaleryl-CoA dehydrogenase in lipogenesis.
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PMID:Leucine catabolism during the differentiation of 3T3-L1 cells. Expression of a mitochondrial enzyme system. 630 77

The effect of potassium cyanide on p-nitroanisole O-demethylation in perfused rat livers has been examined. Cyanide (2 mM), an inhibitor of cytochrome oxidase, diminished p-nitroanisole O-demethylation by 50-75% in perfused livers from normal and phenobarbital-treated rats, but had much less effect on hepatic microsomal p-nitroanisole O-demethylation. The inhibition was also observed in livers where the activity of the pentose phosphate shunt was abolished by pretreatment with 6-aminonicotinamide. Cyanide infusion decreased hepatic ATP/ADP ratios and cellular concentrations of glutamate, alpha-ketoglutarate, and isocitrate, but caused an increase in the NADP+/NADPH ratio. Rates of NADPH generation via the pentose phosphate shunt were unchanged by cyanide, and hepatic concentrations of glucose 6-phosphate were markedly increased by cyanide. Thus, inhibition of p-nitroanisole metabolism could not be explained solely by a direct interaction of cyanide with mixed-function oxidases or diminished NADPH generation via the pentose cycle. These data indicate that cyanide inhibits mixed-function oxidation in intact cells by diminishing the generation of NADPH from sources other than the pentose cycle. Further, these data are consistent with the hypothesis that some NADPH for mixed-function oxidation arises from cyanide-sensitive mitochondrial sources.
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PMID:Inhibition of p-nitroanisole O-demethylation in perfused rat liver by potassium cyanide. 631 Nov 7

In stress-resistant animals exposed to 5-minute immobilization, the metabolic reaction of leukocytes was marked by an increase in the activity of G-6-PDH, hexokinase (HK), cytochrome oxidase (CCO) accompanied by a decrease in the activity of succinate dehydrogenase (SDH). In stress-labile animals, there was a decrease in the activity of G-6-PDH, HK, CCO with an increase in the activity of SDH. The orientation of enzymatic processes in leukocytes of stress-labile animals after immobilization and of stress-resistant animals following intravenous injection of propranolol was discovered to be similar. After propranolol injection leukocytes did not show any glucose, while the activity of G-6-PDH, HK and CCO descended. Injection of propranolol decreased the animal's resistance to traumatic shock. In stress-resistant animals exposed to trauma after the blockade of beta-adrenoreactive structures, the metabolic reaction was marked by low mobility restitution of energy processes as was the case in stress-labile animals during the development of a severe shock.
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PMID:[Metabolic reaction of leukocytes in the course of experimental traumatic shock of varying intensity and on exposure to obzidan]. 632 78

relationship between levels of cAMP and catabolite repression in yeasts has been investigated. Strains of Saccharomyces cerevisiae, Schizosaccharomyces pombe and Kluyveromyces fragilis were used. The yeasts were grown on different carbon sources to attain various degrees of repression. Galactose repressed as much as glucose, while maltose was less effective. Full derepression was achieved with ethanol. The enzymes tested were fructose-bisphosphatase, malate dehydrogenase, glutamate dehydrogenase (NAD dependent), cytochrome oxidase and isocitrate lyase (this last enzyme was found to be absent in Schizosaccharomyces). The levels of cAMP were 2-3 times higher in the repressed conditions than in the derepressed ones. It is therefore concluded that in yeasts catabolite repression is not mediated by a lowering of the intracellular concentration of cAMP.
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PMID:Catabolite repression in yeasts is not associated with low levels of cAMP. 632 8


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