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)

Severe iron deficiency anemia in rats causes a decrease in the activities of iron-containing enzymes in skeletal muscle mitochondria, and subsequent diminished respiratory activity has been linked to lowered work capacity. It was suggested that loss of mitochondrial alpha-glycerophosphate dehydrogenase activity plays a particularly important role in this process and, by inference, in the clinical manifestations of iron deficiency anemia. This view may be ill founded, inasmuch as other pathways with potentially greater activity are capable of transporting reducing equivalents from the cytosol into the mitochondria in mammalian skeletal muscle. In our experiments, iron deficiency anemia of a severity on the order of that in humans was produced in guinea pigs. Mitochondria from skeletal muscles of test animals exhibited respiration rates diminished by 24% to 36% compared with control mitochondria in the presence of several substrates. However, differences in respiration were not observed with alpha-glycerophosphate as substrate, nor were there differences in alpha-glycerophosphate dehydrogenase enzyme activity between mitochondria from iron-deficient and control animals. Although cytochrome oxidase activity and muscle mitochondrial protein content were the same in both groups of guinea pigs, cytochrome and flavoprotein concentrations were lower in mitochondria from iron-deficient animals and there was a preferential loss of cytochrome c + c1. Iron deficiency anemia in guinea pigs thus results in impaired oxygen metabolism in skeletal muscle mitochondria that is associated with a general decrease in the concentrations of iron-containing electron transport chain components as well as with an alteration in chain stoichiometry.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Iron deficiency anemia: mitochondrial alpha-glycerophosphate dehydrogenase in guinea pig skeletal muscle. 298 41

Most of the previous studies on the effects of iron deficiency on skeletal muscle respiratory capacity and work performance have been investigated in severe or moderate iron-deficiency anemia. We report here that even in mild iron deficiency where the hemoglobin concentration was 10 g/dl and the iron stores in livers and spleen were not completely depleted, a marked reduction in succinate dehydrogenase was observed in skeletal muscles but not in heart. Similarly, cytochrome oxidase activities were reduced. Although no significant change in glycerophosphate dehydrogenase was detected in the iron-deficient rats, exposure to cold in this group greatly reduced this enzyme activity. As cold acclimatization accelerates marrow erythropoiesis (20) which in turn, demands more iron, it seems that in the iron-insufficient state, this iron demand for marrow activity may persist at the expense of the tissue iron pool, resulting in a marked reduction in glycerophosphate dehydrogenase activities. Since succinate dehydrogenase plays a significant role in the impairment of mitochondrial function and early fatigue of iron-deficient muscle (11), the present study shows that even in mild iron deficiency, some loss of muscle functions could result as succinate dehydrogenase activities were greatly reduced.
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PMID:Biochemical effects of mild iron deficiency and cold acclimatization on rat skeletal muscle. 300 73

The response of an established line of non-transformed adult rat liver epithelial cells (ARL 15) to thyroid hormone (T3) (3,5,3'-triiodothyronine) was characterized. Exposure of confluent monolayers to 1.10(-8) M T3 for 3 days increased O2 consumption (QO2) between 14-58%, ouabain-sensitive Rb+ uptake 26%, (Na+ + K+)-ATPase activity 32%, alpha-glycerophosphate dehydrogenase activity 103% and cytochrome oxidase activity 208%. The ARL 15 cells, maintained in continuous culture, therefore, exhibit the hallmarks of an authentic physiological response to thyroid hormone.
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PMID:The response of an established line of rat liver cells to thyroid hormone. 301 38

Some metabolic indicators of thyroid hormone activity have been investigated in rats fed on either protein-deficient or energy-restricted diets. Rats were divided into three groups. Control animals were maintained on a diet of protein energy: total energy (P:E) value of 0.20, while the low-protein group (LP) were allowed ad lib. access to food of P:E 0.03. Energy-restricted (ER) rats were given limited amounts of a control diet (P:E 0.20) such that their rate of growth matched that of LP animals. Animals fed on the LP diet had elevated plasma concentrations of both total and free triiodothyronine (T3) concentrations whereas those on the ER regiment showed values below those of controls. The activities of mitochondrial alpha-glycerol-3-phosphate dehydrogenase (EC 1.1.99.5) and of the alpha-glycerol-3-phosphate shuttle system were elevated in the liver of LP rats, but malate-aspartate shuttle operation was reduced. All three activities were reduced in ER animals. Cytochrome c oxidase (EC 1.9.3.1) activity of brown adipose tissue indicated a high rate of thermogenic activity in this tissue in LP rats, but ER animals showed some evidence of below normal function. The results indicate that both the raised plasma T3 of LP rats and the reduced levels observed in ER animals are physiologically significant.
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PMID:Evidence suggesting that the elevated plasma triiodothyronine concentration of rats fed on protein deficient diets is physiologically active. 390 23

Activities of the enzymes monoamine oxidase (EC 1.4.3.4), alpha-glycerophosphate dehydrogenase (EC 1.1.99.5) and cytochrome oxidase (EC 1.9.3.1) were determined in homogenates and in the mitochondrial fraction prepared from individual regions of pig brain. The variation in the activity of alpha-glycerophosphate dehydrogenase paralleled that of cytochrome oxidase, but this was not the case with monoamine oxidase. The differences in the activities of the enzymes among homogenates of the various regions of the brain persisted in mitochondria prepared from these homogenates. The purification of these three enzymes paralleled each other when mitochondria were prepared, suggesting that the three enzymes are bound to the same particles.
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PMID:The distribution of monoamine oxidase and alpha-glycerophosphate dehydrogenase in pig brain. 429 41

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

Two experiments were conducted to determine if variations in diet composition sufficient to alter circulating triiodothyronine (T3) concentration would influence hepatic mitochondrial metabolism. In experiment 1, mitochondrial respiration and the activity of succinate dehydrogenase (SDH), cytochrome oxidase (CO) and alpha glycerophosphate dehydrogenase (m alpha-GPD) were measured in 42-day-old male rats fed diets containing casein/carbohydrate/fat: 8/73/10% (low protein), 22/59/10% (control protein), and 45/36/10% (high protein) for 3 weeks. When compared to control, serum T3 was increased 2-3 times in the low and decreased 19% in the high protein-fed groups. Mitochondria isolated from low protein-fed rats consumed less oxygen in both state 4 and state 3 with succinate as substrate when compared to control or high protein fed rats. However, ADP/O and respiratory control (RC) ratios were similar in all groups. Activity of SDH and CO was decreased only in low protein-fed rats. M alpha-GPD activity was increased in the low and decreased in the high protein fed-rats. In experiment 2, alpha-glycerophosphate shuttle activity was increased 2-3 fold and malate-aspartate shuttle activity decreased 60% in intact mitochondria isolated from low protein-fed rats when compared to rats pair-fed control diet. These results suggest a role for diet composition as a regulator of hepatic intermediary metabolism mediated by thyroid hormones.
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PMID:Influence of diet composition on serum triiodothyronine (T3) concentration, hepatic mitochondrial metabolism and shuttle system activity in rats. 625 66

Young rats were made iron deficient by feeding them a low-iron diet for 8 wk. Iron deficiency resulted in a 50% decrease in cytochrome c and cytochrome oxidase and a 26% decrease in mitochondrial glycerol-3-phosphate dehydrogenase activity in skeletal muscle. Respiratory capacity of muscle homogenates was reduced 55%. After 8 days of iron treatment, respiratory capacity, cytochrome c, cytochrome oxidase, and glycerol-3-phosphate dehydrogenase had returned 50% toward normal. Maximum O2 uptake of contracting hindlimb muscles averaged 8.5 mumol O2.min-1.g-1 in control, 4.3 mumol O2.min-1.g-1 in iron-deficient, and 6.2 mumol O2.min-1.g-1 in the 8-day-iron-repleted rats. Muscle fatigue during 10 min of stimulation was greater in the iron-deficient group. Lactate concentration in red muscle was higher in iron-deficient than in control rats after stimulation. The muscle fatigue and lactate responses returned 50% toward normal during 8 days of iron treatment. We conclude that iron deficiency results in a decrease in skeletal muscle capacity for aerobic metabolism and, by this mechanism, increases susceptibility to fatigue.
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PMID:Physiological and biochemical effects of iron deficiency on rat skeletal muscle. 626 4

The activity of alpha-glycerophosphate dehydrogenase and succinate dehydrogenase suffers almost no changes during the chick embryogenesis, whereas the activity of cytochrome oxidase increases by 20--25%. The activity of these enzymes in the embryos exceeded that in the adult birds. The injection of thyroxine during embryogenesis did not affect the activity of the enzymes under study but in chickens stimulated the activity of mitochondrial enzymes. The increase of activity of alpha-glycerophosphate dehydrogenase, cytochrome oxidase and succinate dehydrogenase was also noted in young rats.
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PMID:[Effect of thyroxine on the activity of a series of mitochondrial enzymes during the process of development]. 627 Jun 8

Four days of fasting in the rat reduced brown-adipose-tissue (BAT) mass, mitochondrial protein, and tissue protein content. Specific binding of guanosine diposphate (GDP) to BAT mitochondria was depressed by 55% in 4d-fasted rats. Rats fasted for 3 d, and then refed a single carbohydrate meal (40 kJ), showed a significant increase in specific GDP-binding (27% above fasted) 24 h later, and a large increase in total binding. Specific activities of cytochrome oxidase and alpha-glycerophosphate dehydrogenase in BAT mitochondria were not significantly affected by fasting or refeeding. These results suggest that BAT may be partly responsible for the fall in metabolic rate associated with fasting and the delayed increase after carbohydrate refeeding. These effects may be due to changes in the mitochondrial proton-conductance pathway in brown fat.
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PMID:Brown fat activity in fasted and refed rats. 673 60


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