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:1.1.1.41 (isocitrate dehydrogenase)
3,101 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of ionic strength and pH on the release of some enzymes of the matrix of peroxisomes in rat's liver was studied. Catalase, L ALpha-hydroxy acid oxidase, isocitrate dehydrogenase, glycerophosphate dehydrogenase and lactate dehydrogenase were easily released from the particles during their lysis and treatment with 0.16 M KCl, whereas urate oxidase, NADH cytochrome c reductase and D-amino acid oxidase were not solubilized. After the solubilization of peroxisomal membrane by 0.2% Triton X-100, the remaining core contained about 50% amino acid oxidase activity, and had 1.28--1.30 g/cm3 density. These results suggest that D-amino acid oxidase associates with urate oxidase in the peroxisomal core.
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PMID:[Enzymologic study of the structural organization of the matrix or rat liver peroxisomes]. 2 68

1. The activity of NAD+-linked isocitrate dehydrogenase from the radular muscle of the whelk is higher than those in many vertebrate muscles and only slightly lower than in the flight muscles of insects. The enzyme activity from the whelk (Buccinum undatum) is stable for several hours after homogenization of the radular muscle, whereas that from insect flight muscle is very unstable. Consequently, the enzyme from the whelk muscle is suitable for a systematic investigation of the effects of Ca2+ and ADP. 2. The sigmoid response of the enzyme activity to isocitrate concentration is markedly increased by raising the Ca2+ concentration from 0.001 to 10 muM, but it is decreased by ADP. The inhibitory effect of Ca2+ is most pronounced at pH7.1; it is not observed at pH 6.5. Similar effects are observed for the enzyme from the flight muscle of the locust (Schistocerca gregaria) and the water bug (Lethocerus cordofanus). The percentage activation by ADP of the enzyme from either the whelk or the insects is greater at 10 muM-Ca2+, and 50% of the maximum activation is obtained at 0.10 and 0.16 mM-ADP for the enzyme from whelk and locust respectively at this Ca2+ concentration. At 10 muM-Ca2+ in the absence of added ADP, the apparent Km for isocitrate is markedly higher than in other conditions. Ca2+ concentrations of 0.01, 0.1 and 0.2 muM cause 50% inhibition of maximum activity of the enzyme from the muscles of the whelk, locust and water bug respectively. 3. Recent work has indicated that mitochondria may play a complementary role to the sarcoplasmic reticulum in the control of the distribution of Ca2+ in muscle. The opposite effects of Ca2+ on the activities of isocitrate dehydrogenase and mitochondrial glycerol phosphate dehydrogenase from muscle tissue are consistent with the hypothesis that changes in the intracellular distribution of Ca2+ control the activities of these two enzymes in order to stimulate energy production for the contraction process in the muscle. Although both enzymes are mitochondrial, glycerol phosphate dehydrogenase resides on the outer surface of the inner membrane and responds to sarcoplasmic changes in Ca2+ concentration (i.e. an increase during contraction), whereas the isocitrate dehydrogenase resides in the matrix of the mitochondria and responds to intramitochondrial concentrations of Ca2+ (i.e. a decrease during contraction). It is suggested that changes in intramitochondrial Ca2+ concentrations are primarily responsible for regulation of the activity of NAD+-isocitrate dehydrogenase in order to control energy formation for the contractile process. However, when the muscle is at rest, changes in intramitochondrial concentrations of ADP may regulate energy formation for non-contractile processes.
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PMID:Effects of calcium ions and adenosine diphosphate on the activities of NAD+-linked isocitrate dehydrogenase from the radular muscles of the whelk and flight muscles of insects. 18 26

We have screened the bloodstream form of Trypanosoma brucei for the presence of enzymes that could serve as markers for the microbodies and the highly repressed mitochondrion of this organism. None of seven known microbody enzymes were detected at all, but glycerol-3-phosphate oxidase, ATPase, isocitrate dehydrogenase, acid phosphatase and part of the hyperoxide dismutase and malate dehydrogenase activities were found to be particle-bound after fractionation of homogenates by differential centrifugation. Part of the ATPase activity was sensitive to oligomycin, an inhibitor of oxidative phosphorylation. This oligomycin-sensitive activity can serve as a specific marker for the mitochondria. More than 80% of the NAD+-linked glycerol-3-phosphate dehydrogenase in T. brucei was found to be particulate and latent. The enzyme could be activated by Triton X-100, by the combined action of sonication and salt, but not by salt alone, and partially by freezing and thawing. We conclude that the NAD+-linked glycerol-3-phosphate dehydrogenase is located inside an organelle.
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PMID:Particle-bound enzymes in the bloodstream form of Trypanosoma brucei. 19 9

The segmentation of the proximal tubules in the kidney of the female rat was studied by means of enzyme histochemical reactions and the results compared with those observed in male and recently described by Jacobsen and J0rgensen (1973 a). Reactions were performed for the following soluble, coezyme-dependent oxido-reductases: glucose 6-phosphate dehydrogenase, alpha-glycerophosphate dehydrogenase, 3 alpha-hydroxysteroid dehydrogenase, NAD-as well as NADP-dependent isocitrate dehydrogenases, NAD-dependent malate dehydrogenase, NADP-dependent, decarboxylating malate dehydrogenase, uridine diphosphate glucose dehydrogenase. Measures were taken to reduce enzyme diffusion and eliminate interference from tissue tetrazolium reductases. Furthermore, reactions were performed for a number of less soluble or insoluble enzymes: glucose 6-phosphatase, mitochondrial alpha-glycerophosphate dehydrogenase, beta-hydroxybutyrate dehydrogenase, succinate dehydrogenase and tetrazolium reductases. In the proximal tubules of the female rat all enzymes studied--except beta-hydroxybutyrate dehydrogenase--showed segmental differences, most of them clearly revealing three segments. Sex differences were found concerning all enzymes except uridine diphosphate glucose dehydrogenase and NADP-dependent isocitrate dehydrogenase. The most pronounced sex-related differences were seen in the third segment in which part the male rat showed highest activity in respect to tetrazolium reductases, NAD-dependent isocitrate dehydrogenase, succinate dehydrogenase, beta-hydroxybutyrate dehydrogenase, 3 alpha-hydroxysteroid dehydrogenase and glucose 6-phosphate dehydrogenase and the female in respect to glucose 6-phosphatase, alpha-glycerophosphate dehydrogenases, and NADP-dependent, decarboxylating malate dehydrogenase. A few of the enzymes exhibited minor sex differences in the first two segments.
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PMID:Enzyme histochemical observations on the segmentation of the proximal tubules in the kidney of the female rat. 23 55

1. Rate sedimentation and isopycnic centrifugation were used to analyse the subcellular sites of enzymes in homogenates of goldfish intestinal mucosa. 2. The results allowed the following allocations to be made: carnitine acetyl transferase-mitochondrial and peroxisomal, xanthine dehydrogenase and NAD: alpha-glycerophosphate dehydrogenase soluble phase, NADP: isocitrate dehydrogenase soluble phase and mitochondrial, and 2-naphthyl laurate hydrolase microsomal and/or brush border. 3. Histochemistry confirmed the use of alkaline phosphatase and 1-naphthyl acetate esterase as brush border and microsome markers respectively. 4. Urate oxidase, allantoinase, allantoicase, xanthine oxidase and glycollate/lactate oxidase, activities were undetectable, and 1-naphthyl palmitate hydrolase was present only as a contaminant from pancreas.
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PMID:Intestinal peroxisomes of goldfish (Carassius auratus)--examination for hydrolase, dehydrogenase and carnitine acetyltransferase activities. 31 95

1. Coupled mitochondria were isolated from exponentially growing Physarum polycephalum. 2. Activity of malate dehydrogenase (oxalacetate reduction) was 10.9 mumol/min/mg protein; the apparent Km was 64 microM. 3. The activity of NADP-isocitric dehydrogenase (IDH) was 110 nmol/min/mg with apparent Km of 35 microM. 4. NAD-IDH showed allosteric properties with AMP as a positive modulator. The apparent Km for the unmodulated activity, 2 mM, was decreased to 0.95 mM by 0.13 mM AMP. 5. Succinic dehydrogenase activity was estimated as three times higher than that of alpha-glycerophosphate dehydrogenase. 6. Mitochondria contained significant amounts of phenolic compounds. Protein estimation by the Bradford method is recommended.
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PMID:Activity of some dehydrogenase enzymes in mitochondria from Physarum polycephalum. 31 27

Extracts of the horse and sheep strains of Echinococcus granulosus and E. multilocularis were compared on the basis of their isoenzyme patterns for 10 enzymes by means of isoelectric focusing in polyacrylamide gels. The enzymes examined were: acid phosphatase, lactate dehydrogenase, malate dehydrogenase, malic enzyme, phosphoglucoseisomerase, isocitrate dehydrogenase, adenylate kinase, aldolase and alpha-glycerophosphate dehydrogenase. Interspecific and intraspecific differences are apparent in the isoenzyme profiles of all the enzymes except adenylate kinase; the pattern and activity of adenylate kinase are identical for both strains of E. granulosus but this enzyme clearly distinguishes these forms from E. multilocularis. The absence of electromorphic variation in any of the enzymes from either form of E. granulosus may be a result of the self-fertilizing hermaphraditism of these organisms.
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PMID:Isoelectric focusing of some enzymes from Echinococcus granulosus (horse and sheep strains) and E. multilocularis. 47 21

Mycotoxic porcine nephropathy was induced by p.o. administration of crystalline ochratoxin A for periods of 5 days, 3 months and 2 years. Enzyme activities of the renal tissue were studied histochemically. These were NADH-tetrazolium reductase, NADPH-tetrazolium reductase, lactate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, glucose-6-phosphate dehydrogenase, alpha-glycerophosphate dehydrogenase, unspecific acid phosphatase and unspecific alkaline phosphatase. The activity of NADH-tetrazolium reductase and succinate dehydrogenase was reduced in the proximal tubule of all nephrons after 5 days ochratoxin A exposure and remained reduced after 3 months and 2 years exposure. The effect of ochratoxin A on these enzymes would appear to cause the impairment of proximal tubular function and the morphological changes observed in the proximal tubule in ochratoxin A-induced mycotoxic porcine nephropathy. The localization of alterations in enzyme activity corresponds to the localization of ochratoxin A previously demonstrated in the kidney. The activities of NADPH-tetrazolium reductase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase and unspecific alkaline phosphatase were reduced focally corresponding to the areas with focal tubular atrophy and the degree of reduction was roughly parallel to the degree of atrophy.
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PMID:Ochratoxin A-induced mycotoxic porcine nephropathy: alterations in enzyme activity in tubular cells. 47 26

Two independently derived embryonic Drosophila cell culture lines were examined for 19 gene-enzyme systems. At two loci, alpha-glycerophosphate dehydrogenase on chromosome 2, and isocitrate dehydrogenase on chromosome 3, allelic variation was detected. These can now serve as genetic markers to identify hybrid cell clones. Quantitative differences between cell lines were found for five enzymes.
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PMID:Isozyme and allozyme patterns in embryonic Drosophila cell culture lines. 58 36

1. Flight by insects is characterized by the most intense respiration known in biology and also the most controlled. Thus insect flight muscle may be the tissue of choice for the study of biochemical adaptation in the control of catabolism and biological oxidations, and many of the results obtained with insects have a significance and a relevance that transcend the boundaries between classes. In insects, such as the blowfly, flight is distinguished additionally by high wingbeat frequencies and an asynchronous type of excitation-contraction coupling. In spite of this intense muscular work, metabolic processes are not limited by the availability of oxygen. Also of importance is the morphological organization of the flight muscle and mitochondria, which have evolved ultrastructurally and biochemically into an effective catabolic machine. 2. In the fly, carbohydrate, principally glycogen, is the sole metabolic fuel; fats are not used in flight and enzymes concerned with fatty acid utilization are virtually lacking. Glycogenolysis does not lead to lactic acid; instead, the end products of glycolysis are pyruvate and alpha-glycerophosphate. The alpha-glycerophosphate cycle provides a mechanism not only for the reoxidation of glycolytically produced NADH but also for the stoicheiometric formation from each molecule of hexose equivalent of two molecules of pyruvate, which are then available for oxidation via the tricarboxylate cycle. The absence of dicarboxylate and tricarboxylate carriers from the mitochondria ensures that tricarboxylate-cycle intermediates do not exit from the mitochondrion but that pyruvate is oxidized to completion. On initiation of flight, mitochondrial oxidation of pyruvate is impeded by the lack of tricarboxylate-cycle intermediates for the generation of oxaloacetate. This is circumvented by the oxidation of proline. 3. The controls on metabolism in flight muscle, i.e. (1) glycogenolysis at phosphorylase and phosphorylase kinase, (2) glycolysis at phosphofructokinase, (3) alpha-glycerophosphate dehydrogenase, (4) proline dehydrogenase and (5) tricarboxylate cycle at isocitrate dehydrogenase, are effected by the phosphate potential and/or Ca2+. It is suggested that the metabolic changes, such as those seen in the rest-to-flight transition, are achieved by the concerted actions of these effectors at the different loci.
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PMID:Biochemical adaptations for flight in the insect. 78 15


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