Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.9.3.1 (cytochrome oxidase)
 8,822 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The contribution of muscle tissue to the increased metabolic efficiency of the obese (fa/fa) Zucker rat at 6 wk of age was examined. In vitro O2 consumption was similar in obese and nonobese soleus and extensor digitorum longus (EDL) muscles, whether the animals were fed ad libitum, fasted, or treated with triiodothyronine. No phenotypic difference in the in vitro O2 consumption was seen when the muscles were preincubated with or without exogenous insulin. Pyruvate kinase, citrate synthase, succinate dehydrogenase, and cytochrome oxidase activities were similar in the soleus and the EDL muscles of both phenotypes. Phosphofructokinase and lactate dehydrogenase activities were higher in the soleus muscles from the obese rats, whereas hexokinase activities were higher in the EDL muscles from the nonobese rats. Mitochondrial and whole muscle homogenate respiration rates were similar in both phenotypes. The soleus and EDL muscles from the obese animals weighed less than those from the nonobese, but empty carcass weights were similar. Taken together these data suggest that muscle mass, muscle O2 consumption, and muscle oxidative capacity are similar in 6-wk-old obese and nonobese rats. Therefore other tissues are probably responsible for the increased metabolic efficiency of the young obese rat.
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PMID:Oxygen consumption and oxidative capacity of muscles from young obese and nonobese Zucker rats. 609 7

Mitochondria were isolated from whole homogenates of normal liver and Novikoff hepatomas using reorienting rate zonal centrifugation on sucrose gradients. The activities of several mitochondrial-specific enzymes and ultrastructure were compared in the two tissues. Our results indicate that cytochrome oxidase, lipoamide dehydrogenase, malate dehydrogenase, and succinate dehydrogenase activities are all higher in liver homogenates than in Novikoff hepatoma homogenates. Mitochondrial hexokinase, however, is much greater in the hepatoma than in liver. The activity of these enzymes in isolated mitochondria displayed a much different pattern. Both cytochrome oxidase and succinate dehydrogenase activities were higher in hepatoma mitochondria than in liver mitochondria. Lipoamide dehydrogenase and malate dehydrogenase, conversely, were higher in liver mitochondria. Hexokinase was found to be virtually absent in liver mitochondria but plentiful in hepatoma mitochondria. Ultrastructural studies have shown that the hepatoma mitochondria are much smaller in size, which results in a decreased rate of migration into the gradient. These studies have also shown that normal liver consists of predominantly "condensed" forms of mitochondria, whereas hepatoma contained a majority of "twisted" species. Experiments using 1% bovine serum albumin in the homogenization procedures and in the gradient have confirmed earlier observations that bovine serum albumin is essential for optimal isolation of neoplastic mitochondria.
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PMID:Characteristics of mitochondria isolated by rate zonal centrifugation from normal liver and Novikoff hepatomas. 624 94

The distribution of hexokinase, a general glycolytic enzyme, was compared to that of cytochrome oxidase and acetylcholinesterase (AChE) in the somatosensory cortex and the superior colliculus of the rat. The vibrissal barrel fields of the adult rat contain high hexokinase and cytochrome oxidase activity and low AChE activity. In the superior colliculus, hexokinase activity was highest in cell layers and discrete foci of intense activity were observed in the deep grey layer. This distribution was different from that of both cytochrome oxidase and AChE in this structure.
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PMID:The distribution of hexokinase compared to cytochrome oxidase and acetylcholinesterase in the somatosensory cortex and the superior colliculus of the rat. 631 13

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

The metabolic characteristics of 12 skeletal muscles of the sheep were studied. Glycolytic activities (hexokinase, glycogen synthetase I and D, phosphorylase a and b, phosphofructokinase) were measured. Myofibrillar ATPase activity was evaluated. Oxygen consumption, respiratory control and carnitine palmityl transferase, isocitrate dehydrogenase, succinate dehydrogenase and cytochrome oxidase activities were measured in isolated mitochondria. Three metabolic types could be distinguished; (1) essentially oxidative slow twitch muscles, typified by the supraspinatus and infraspinatus, having low ATPase activity, (2) fast twitch red muscles, typified by the longissimus dorsi and the semimembranosus, having a higher ATPase activity and both high oxidative and high glycolytic activity, and (3) essentially glycolytic fast twitch muscles, typified by the tensor fascia lata and the semitendinosus, having the highest ATPase activity.
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PMID:Metabolic types of muscle in the sheep: I. Myosin ATPase, glycolytic, and mitochondrial enzyme activities. 645 90

The effect of intermittent normobaric hypoxia and of biological pyrimidines (uridine and cytidine) on the specific activities of some enzymes related to cerebral energy metabolism were studied. Measurement were carried out on the following: homogenate in toto; purified mitochondrial fraction; crude synaptosomal fraction, in different areas of rat brain: cerebral cortex, hippocampus, corpus striatum, hypothalamus, cerebellum, and medulla oblongata. Intermittent normobaric hypoxia (12 hours daily for 5 days) caused modifications of the enzyme activities in the homogenate in toto (decrease of hexokinase in cerebellum; increase of pyruvate kinase in medulla oblongata), in the purified mitochondrial fraction (increase of succinate dehydrogenase in the corpus striatum) and in the crude synaptosomal fraction (decrease of cytochrome oxidase activity in cerebral cortex, hippocampus, and cerebellum; decrease of malate dehydrogenase in hippocampus and cerebellum; decrease of lactate dehydrogenase in cerebellum). Daily treatment with cytidine or uridine altered some enzyme activities either affected or unaffected by intermittent hypoxia.
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PMID:Influence of intermittent hypoxia and pyrimidinic nucleosides on cerebral enzymatic activities related to energy transduction. 649 41

Hexokinase (ATP: D-hexose-6-phosphotransferase, EC 2.7.1.1) activity was determined in subcellular fractions prepared from pea (Pisum sativum) leaf homogenates. About 60% of the total detectable activity of hexokinase was found associated with a particulate fraction consisting essentially of mitochondria and chloroplasts and free of cytosol contamination. The hexokinase specific activity of the particulate fraction was 2-fold higher than that of the homogenate and about 4-fold higher than that of the cytosol. Using a specially designed isokinetic-isopycnic sucrose density gradient centrifugation method, the distribution of hexokinase activity correlated with that of the mitochondrial marker (cytochrome oxidase) and not with that of the chloroplast membrane marker ( chlorophyll ) or that of the cytosol marker (phosphoenolpyruvate carboxylase). Thus, the hexokinase/mitochondria ratio was close to 1.0 along the entire gradient, while the hexokinase/chloroplast ratio varied over a 10-fold range. The results strongly suggest that hexokinase is predominantly bound to mitochondria of pea leaves, and that pea leaf chloroplasts are essentially devoid of any specifically associated hexokinase activity. This work provides the first demonstration of a specific association of hexokinase with mitochondria from photosynthetic tissues of higher plants.
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PMID:Subcellular localization of hexokinase in pea leaves. Evidence for the predominance of a mitochondrially bound form. 673 23

The maximal rate of some cerebral enzymatic activities related to energy transduction (hexokinase; phosphofructokinase; lactate dehydrogenase; citrate synthase; malate dehydrogenase; total NADH-cytochrome c reductase; cytochrome oxidase), amino acid metabolism (glutamate decarboxylase; glutamate dehydrogenase) and cholinergic metabolism (acetylcholine esterase) were tested in the cerebral cortex and in sub-cortical area of rats. The evaluations were performed both in the homogenate in toto and in the crude mitochondrial fraction, before and after a postdecapitative normothermic ischemia of 5, 10, 20, and 40 min duration. The results are discussed also with respect to the pharmacological pretreatment with two biological substances which may modulate amino acid (L-alanine) and phospholipid metabolism (CDP-choline). The analysis of the present data suggests the occurrence in brain tissue of a variety of interrelated factors implicated in the ischemia-induced changes of the maximal rate of the enzymatic activities related to the energy transduction. These include: (a) rearrangement of the enzymatic activities because of the changed metabolic and chemico-physical condition; (b) decrease in the activity of enzymes related to the electron transfer chain and glycolysis; (c) changes in enzymes related to mitochondrial membranes. The effects of in vivo administration of alanine or CDP-choline, even if significant, are not consistent throughout the time period studied.
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PMID:Changes induced by ischemia on some cerebral enzymatic activities related to energy transduction and amino acid metabolism. 685 30

The energy metabolism of the English E-CMO strain of contagious equine metritis bacterium was studied in whole cells and cell extracts. This bacterium appears to have an active Krebs cycle and probably obtains energy by oxidative phosphorylation since glycolysis and the hexose monophosphate pathways appear to be absent. These conclusions are based on the findings that [U-14C]glucose incorporation by this bacterium is below the level of detection, and that respiration is stimulated by Krebs cycle intermediates (i.e., malate, citrate, and succinate), but not by glucose, fructose, maltose, or sucrose. Furthermore, support comes from the fact that enzymes generally associated with the Krebs cycle and electron transport (i.e., malate dehydrogenase, succinate dehydrogenase, isocitrate dehydrogenase, fumarate hydratase, malate dehydrogenase [decarboxylating], cytochrome oxidase, superoxide dismutase, NADH dehydrogenase, and catalase) were detected. Those enzymes normally associated with glycolysis and the hexose monophosphate pathways (i.e., hexokinase, glucose 6-phosphate dehydrogenase, fructose biphosphate aldolase, glycerol 3-phosphate dehydrogenase, phosphoenolpyruvate carboxykinase, pyruvate kinase, phosphate acetyl transferase, acetate kinase, alcohol dehydrogenase, and lactate dehydrogenase) were below the level of detection.
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PMID:Energy metabolism of the contagious equine metritis bacterium. 708 71

The energy metabolism was evaluated in gastrocnemius muscle from 3-month-old rats subjected to either mild or severe 4-week intermittent normobaric hypoxia. Furthermore, 4-week treatment with CNS-acting drugs, namely, alpha-adrenergic (delta-yohimbine), vasodilator (papaverine, pinacidil), or oxygen-increasing (almitrine) agents was performed. The muscular concentration of the following metabolites was evaluated: glycogen, glucose, glucose 6-phosphate, pyruvate, lactate, lactate-to-pyruvate ratio; citrate, alpha-ketoglutarate, succinate, malate; aspartate, glutamate, alanine; ammonia; ATP, ADP, AMP, creatine phosphate. Furthermore the Vmax of the following muscular enzymes was evaluated: hexokinase, phosphofructokinase, pyruvate kinase, lactate dehydrogenase; citrate synthase, malate dehydrogenase; total NADH cytochrome c reductase; cytochrome oxidase. The adaptation to chronic intermittent normobaric mild or severe hypoxia induced alterations of the components in the anaerobic glycolytic pathway [as supported by the increased activity of lactate dehydrogenase and/or hexokinase, resulting in the decreased glycolytic substrate concentration consistent with the increased lactate production and lactate-to-pyruvate ratio] and in the mitochondrial mechanism [as supported by the decreased activity of malate dehydrogenase and/or citrate synthase resulting in the decreased concentration of some key components in the tricarboxylic acid cycle]. The effect of the concomitant pharmacological treatment suggests that the action of CNS-acting drugs could be also related to their direct influence on the muscular biochemical mechanisms linked to energy transduction.
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PMID:Modifications by chronic intermittent hypoxia and drug treatment on skeletal muscle metabolism. 778 38


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