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)

Phenotypes of eight red cell enzymes at nine genetic loci were determined in the semi-free-ranging population of rhesus macaques; Macaca mulatta, that inhabit Cayo Santiago. The following enzymes were examined electrophoretically: adenosine deaminase, glucose-6-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, indophenol oxidase, lactate dehydrogenase, malate dehydrogenase, phosphoglucomutase-1, phosphoglumutase-2, and purine nucleoside phosphorylase. Hemolysates from at least 372 animals were analyzed, and no variants of the enzymes were observed with the exception of malate dehydrogenase. Three animals displaying a variant form of malate dehydrogenase were found.
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PMID:Genetic studies of free-ranging macaques of Cayo Santiago. I. Description of the population and some nonpolymorphic red cell enzymes. 41 22

The effect of the switch to aerobic growth conditions was examined in rabbit articular chondrocytes transferred to culture. Spectroscopic analysis of the cytochromes of the respiratory chain shows that only cytochrome b is present in chondrocytes from cartilage, cytochromes c, c1, and a.a3 being undetectable as compared with the typical spectrum found in a primary cell culture on day 4. Steady state levels of RNA transcripts of nuclear (cytochrome c) and mitochondrial genes (cytochrome b and cytochrome oxidase subunits II and III) involved in the oxidative metabolism were determined relative to the RNA transcripts of the nuclear gene for glyceraldehyde phosphate dehydrogenase involved in the glycolytic pathway and to mitochondrial ribosomal RNAs. Chondrocytes transferred to culture showed a general increase in the levels of all transcripts, but the effect on mitochondrial transcripts was much greater (x 20) than the effect on nuclear transcripts (x 3-4). These results show the absence of a coordinate regulation of the expression of mitochondrial and nuclear genes coding for components of the respiratory chain. The increase in mitochondrial DNA triggered by culture conditions does not appear to be sufficient to account for the enhanced transcription. Concomitant with these mitochondrial changes, the level of transcripts for the collagen II gene involved in the differentiation function decreases dramatically (3% of the control on day 3).
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PMID:Mitochondrial biogenesis in rabbit articular chondrocytes transferred to culture. 191 49

The purpose of the study was to verify the influence of several weeks of chronic low-frequency electrical stimulation (LFES) on the metabolic profile and functional capacity of human skeletal muscle. Knee extensor muscles (KEM) of eight subjects were electrically stimulated at 8 Hz for 8 h/day and 6 days/wk. Vastus lateralis muscle samples were taken before, after 4 wk, and after 8 wk of LFES, and activities of anaerobic (creatine kinase, phosphofructokinase, glyceraldehyde-3-phosphate dehydrogenase) and aerobic-oxidative (citrate synthase, 3-hydroxyacyl-CoA dehydrogenase, cytochrome-c oxidase) enzyme markers were determined. KEM dynamic performance was also assessed before, after 4 wk, and after 8 wk of LFES. Activity levels of anaerobic enzymes were not altered, whereas the activity levels of citrate synthase (29%),3-hydroxyacyl-CoA dehydrogenase (22%), and cytochrome-c oxidase (25%) were significantly increased after 4 wk of LFES but were not further increased after 4 additional wk of LFES. KEM performance was also improved (P < 0.05) but leveled off after 4 wk of LFES. Although significant changes were observed, the results of the present study suggest that the muscle characteristics investigated in the current study have a limited capacity of adaptation in response to this form of chronic LFES.
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PMID:Human skeletal muscle adaptation in response to chronic low-frequency electrical stimulation. 783 13

Aging of rats results in slower activities of calcium transport by cardiac calcium adenosinetriphosphatase (ATPase) of the sarcoplasmic reticulum (SR) and mitochondrial cytochrome oxidase (COX). These enzyme activities are faster after exercise training of previously sedentary old rats. Our purpose was to determine whether the expression of the genes encoding SR calcium ATPase (SERCA2a) or COX is altered by exercise training. Old (24-mo-old) male Fischer 344 rats were assigned to SO (sedentary old) or EO (exercised old) groups and compared with younger (12-mo-old) sedentary rats (SM). EO rats were trained on a treadmill for 8-10 wk. SERCA2a and COX mRNAs were lower (P < 0.05) in SO compared with SM and EO, whereas glyceraldehyde 3-phosphate dehydrogenase (GAPDH) and cardiac alpha-actin mRNAs were similar across groups. The immunoreactive protein contents of cardiac calcium ATPase, cytochrome c, sarcomeric actin, and GAPDH followed the changes, when observed, in mRNA contents. Thus pretranslational mechanisms may be modified in some genes during aging and exercise training of previously sedentary old rats.
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PMID:SERCA2a and mitochondrial cytochrome oxidase expression are increased in hearts of exercise-trained old rats. 876 Jan 59

Inhibition of DNA polymerase gamma-function mediated by 3'-azido-3'-deoxythymidine (AZT) has been proposed to cause a myopathy by reducing mitochondrial DNA (mtDNA) replication. Repeated bouts of exercise stimulate an increase in mtDNA replication, mitochondrial content, and mitochondrial volume fraction. Therefore, adaptation of rat skeletal muscle [tibialis anterior (TA)] mitochondria exposed to AZT (1 mg/ml for 35 days) and then to electrical stimulation for 8 h/day (7, 14, 21 days) with continued AZT treatment was examined. Fourteen and 21 days of stimulation increased TA cytochrome oxidase (CO) activity, mtDNA, and CO subunit III and VIc mRNA levels in both groups. The TA CO activity and CO III mRNA increases after 14 and 21 days of stimulation were diminished in AZT-treated rats. TA glyceraldehyde-3-phosphate dehydrogenase was reduced in normal rats after chronic stimulation but was unchanged in AZT-treated rats. Chronic stimulation increased the mitochondrial volume fraction by 80 and 40% in normal and AZT-treated rats, respectively. These results indicate diminution, but not complete inhibition, of mitochondrial adaptation by AZT-treated skeletal muscle in response to stimulation.
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PMID:Skeletal muscle mitochondria from AZT-treated rats have a diminished response to chronic electrical stimulation. 882 81

The etiology of the selective neuronal death that occurs in Huntington's disease (HD) is unknown. Several lines of evidence implicate the involvement of energetic defects and oxidative damage in the disease process, including a recent study that demonstrated an interaction between huntingtin protein and the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Using spectrophotometric assays in postmortem brain tissue, we found evidence of impaired oxidative phosphorylation enzyme activities restricted to the basal ganglia in HD brain, while enzyme activities were unaltered in three regions relatively spared by HD pathology (frontal cortex, parietal cortex, and cerebellum). Citrate synthase-corrected complex II-III activity was markedly reduced in both HD caudate (-29%) and putamen (-67%), and complex IV activity was reduced in HD putamen (-62%). Complex I and GAPDH activities were unaltered in all regions examined. We also measured levels of the oxidative damage product 8-hydroxydeoxyguanosine (OH8dG) in nuclear DNA, and superoxide dismutase (SOD) activity. OH8dG levels were significantly increased in HD caudate. Cytosolic SOD activity was slightly reduced in HD parietal cortex and cerebellum, whereas particulate SOD activity was unaltered in these regions. These results further support a role for metabolic dysfunction and oxidative damage in the pathogenesis of HD.
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PMID:Oxidative damage and metabolic dysfunction in Huntington's disease: selective vulnerability of the basal ganglia. 915 27

The insulin resistance of skeletal muscle in glucose-tolerant obese individuals is associated with reduced activity of oxidative enzymes and a disproportionate increase in activity of glycolytic enzymes. Because non-insulin-dependent diabetes mellitus (NIDDM) is a disorder characterized by even more severe insulin resistance of skeletal muscle and because many individuals with NIDDM are obese, the present study was undertaken to examine whether decreased oxidative and increased glycolytic enzyme activities are also present in NIDDM. Percutaneous biopsy of vatus lateralis muscle was obtained in eight lean (L) and eight obese (O) nondiabetic subjects and in eight obese NIDDM subjects and was assayed for marker enzymes of the glycolytic [phosphofructokinase, glyceraldehyde phosphate dehydrogenase, hexokinase (HK)] and oxidative pathways [citrate synthase (CS), cytochrome-c oxidase], as well as for a glycogenolytic enzyme (glycogen phosphorylase) and a marker of anaerobic ATP resynthesis (creatine kinase). Insulin sensitivity was measured by using the euglycemic clamp technique. Activity for glycolytic enzymes (phosphofructokinase, glyceraldehye phosphate dehydrogenase, HK) was highest in subjects with subjects with NIDDM, following the order of NIDDM > O > L, whereas maximum velocity for oxidative enzymes (CS, cytochrome-c oxidase) was lowest in subjects with NIDDM. The ratio between glycolytic and oxidative enzyme activities within skeletal muscle correlated negatively with insulin sensitivity. The HK/CS ratio had the strongest correlation (r = -0.60, P < 0.01) with insulin sensitivity. In summary, an imbalance between glycolytic and oxidative enzyme capacities is present in NIDDM subjects and is more severe than in obese or lean glucose-tolerant subjects. The altered ratio between glycolytic and oxidative enzyme activities found in skeletal muscle of individuals with NIDDM suggests that a dysregulation between mitochondrial oxidative capacity and capacity for glycolysis is an important component of the expression of insulin resistance.
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PMID:Altered glycolytic and oxidative capacities of skeletal muscle contribute to insulin resistance in NIDDM. 921 60

A developmental block is induced by phosphate in rat embryos at the late two-cell stage. The present study was designed to examine the energy metabolism of rat two-cell blocked and non-blocked embryos. Enzyme activity was measured in individual embryos by histochemical techniques. The activities of malate dehydrogenase, isocitrate dehydrogenase, lactate dehydrogenase, pyruvate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase, glucose-6-phosphatase, and phosphorylase did not differ among non-blocked and blocked embryos. However, the activity of succinate dehydrogenase was significantly decreased in blocked embryos compared with non-blocked embryos. In blocked embryos, cytochrome oxidase activity was distributed homogeneously, but was located at the perinuclear region in non-blocked embryos. Active mitochondrial organization was visualized using the fluorescent probe rhodamine 123 and laser scanning confocal microscopy. In both non-blocked and blocked embryos, mitochondria were distributed homogeneously. The concentration of H2O2 measured fluorometrically in embryos cultured without phosphate did not change significantly during the culture period, but decreased in embryos cultured with phosphate. The timing corresponded to the occurrence of the two-cell block. In summary, these results suggest that the developmental block in rat two-cell embryos is induced by disturbance of mitochondrial energy metabolism.
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PMID:Microscopic analysis of enzyme activity, mitochondrial distribution and hydrogen peroxide in two-cell rat embryos. 986 Nov 63

The physiological role of huntingtin and the mechanisms by which the expanded CAG repeat in ITI5 and its polyglutamine stretch in mutant huntingtin induce Huntington's disease (HD) are unknown. Several techniques have now demonstrated abnormal metabolism in HD brain; direct measurement of respiratory chain enzyme activities has shown severe deficiency of complex II/III and a milder defect of complex IV. We confirm that these abnormalities appear to be confined to the striatum within the HD brain. Analysis of complex II/III activity in HD fibroblasts was normal, despite expression of mutant huntingtin. Although glyceraldehyde 3-phosphate dehydrogenase (a huntingtin binding protein) activity was normal in all areas studied, aconitase activity was decreased to 8% in HD caudate, 27% in putamen, and 52% in cerebral cortex, but normal in HD cerebellum and fibroblasts. We have demonstrated that although complexes II and III are those parts of the respiratory chain most vulnerable to inhibition in the presence of a nitric oxide (NO*) generator, aconitase activity was even more sensitive to inhibition. The pattern of these enzyme deficiencies and their parallel to the anatomical distribution of HD pathology support an important role for NO* and excitotoxicity in HD pathogenesis. Furthermore, based on the biochemical defects we have described, we suggest that NO* generation produces a graded response, with aconitase inhibition followed by complex II/III inhibition and the initiation of a self-amplifying cycle of free radical generation and aconitase inhibition, which results in severe ATP depletion. We propose that these events are important in determining neuronal cell death and are critical steps in the pathogenesis of HD.
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PMID:Biochemical abnormalities and excitotoxicity in Huntington's disease brain. 989 73

Manganism is a disorder characterized by hyperintensities in basal ganglia structures on magnetic resonance imaging which may be the consequence of manganese deposition in these areas. Since manganese is taken up avidly into astrocytes and is known to interfere with cerebral energy metabolism, we studied the effect of this metal on the expression and activity of the glycolytic enzyme glyceraldehyde-3-phosphate dehydrogenase (GAPDH) in primary cultures of astrocytes. Treatment with 100 microM manganese for 7 days increased both the Vmax and Km values for GAPDH which was not reproducible with other divalent metals. Using RT-PCR, increased GAPDH expression was detected in cells exposed to manganese compared with controls. No changes in cytochrome oxidase activity or ATP levels were observed, and lactate production was unaffected, in manganese-treated cells. These findings provide evidence of a possible role for GAPDH in the mediation of the effects of manganese on central nervous system function.
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PMID:Increased expression of glyceraldehyde-3-phosphate dehydrogenase in cultured astrocytes following exposure to manganese. 1040 26


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