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 fixed position of trophoblast in the uterus is preceded by zygote orientation and its contact, adhession and fusion with endometrial cell membrane. These interactions take place in a precise site called "implantation site". The identification of this area by the administration of pontamine blue has allowed biochemical studies which showed an increase (in the site) of glycolytic enzymes activity of the pentose cycle, of beta-glucuramidase and of acid and alkaline phosphatase; with a decrease in catepsine D activity. In non implanted tissue, isocitric dehydrogenase activity is decreased. From the biochemical standpoint the implanted endometrium may be different from the rest, which allows a better knowledge of possible molecular mechanisms related with implantation, as well as the possible inhibition with medication.
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PMID:[New concepts related to implantation. III. Biochemical characteristics]. 74 94

Tricarboyxlic acid cycle activity was examined in Neisseria gonorrhoeae CS-7. The catabolism of glucose in N. gonorrheae by a combination of the Entner-Doudoroff and pentose phosphate pathways resulted in the accumulation of acetate, which was not further catabolized until the glucose was depleted or growth became limiting. Radiorespirometric studies revealed that the label in the 1 position of acetate was converted to CO2 at twice the rate of the label in the 2 position, indicating the presence of a tricarboxylic acid cycle. Growth on glucose markedly reduced the levels of all tricarboxylic acid cycle enzymes except citrate synthase (EC 4.1.3.7). Extracts of glucose-grown cells contained detectable levels of all tricarboxylic acid cycle enzymes except aconitase (EC 4.2.1.3), isocitrate dehydrogenase (EC 1.1.1.42), and a pyridine nucleotide-dependent malate dehydrogenase (EC 1.1.1.37). Extracts of cells capable of oxidizing acetate lacked only the pyridine nucleotide-dependent malate dehydrogenase. In lieu of this enzyem, a particulate pyridine nucleotide-independent malate oxidase (EC 1.1.3.3) was present. This enzyme required flavin adenine dinucleotide for activity and appeared to be associated with the electron transport chain. Radiorespirometric studies utilizing labeled glutamate demonstrated that a portion of the tricarboxylic acid cycle functioned during glucose catabolism. In spite of the presence of all tricarboxylic acid cycle enzymes, N. gonorrhoeae CS-7 was unable to grow in medium supplemented with cycle intermediates.
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PMID:Physiology and metabolism of pathogenic neisseria: tricarboxylic acid cycle activity in Neisseria gonorrhoeae. 82 68

The activity of key enzymes of the citrate (CC), glyoxylate (GC), and pentose phosphate cycles (PPC) was determined in the cells of Candida lipolytica and Candida tropicalis growing on hexadecane and glucose. The activity of isocitrate lyase and malate synthase (enzymes of GC) was very high in hexadecane grown cells but was almost absent in "glucose" grown. The activity of citrate synthase and aconitase was 2-4 times and 1.5-2 times, respectively, higher in the cells, grown on n-alkane. The activity of citrate synthase of "hexadecane" and "glucose" yeasts was higher than the activity of other enzymes of CC (aconitase and isocitrate dehydrogenase), especially in the "hexadecane" cells. The activity of the key enzymes of PPC was almost the same in the yeast cells, grown on "hexadecane" and "glucose". Possible factors causing differences in the activities of the enzymes of GC and CC are discussed. Yeast organisms incapable to grow on n-alkanes were found to be able to grow on acetate (43 strains belonging to 35 yeast species have been studied) and to have a high activity of isocitrate lyase. Therefore, the absence of growth of many yeast strains on n-alkanes is not caused by the absence of the activity of enzymes of GC in these strains.
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PMID:[The activity of citrate glyoxylate and pentosephosphate cycle enzymes during yeast growth on hexadecane and glucose]. 94 Apr 96

In the subcommissural organ (SCO) of the guinea pig, rat, golden hamster, and mouse the activity and distribution of enzymes related to the energy-supplying metabolism and of some marker enzymes of different cell organelles have been investigated by means of mostly modified histochemical methods. The results were compared with findings in the ciliated ependyma of the ventricular wall and with those in the ependyma of the choroid plexus of the third ventricle. In the ependymal part of the SCO only a moderate activity of hexokinase is observed in its specialized columnar cells whereas a high activity is present both in the ciliated ependyma and the choroid plexus. - The staining pattern of glucose-6-phosphatase is similar to that of hexokinase but this enzyme is found is the SCO only. - Likewise hexokinase, glycogen granules and enzymes related to glycogen metabolism (phosphoglucomutase, uridine-diphosphoglucose pyrophosphorylase, glycogen synthetase and phosphorylase) are regularly found most numerous and active in the nuclear and supra-nuclear area of the ependymal part. These enzymes are less active in both the other ependymal regions. - Uridine-diphosphoglucose dehydrogenase could not be demonstrated in the SCO. The NADP-linked enzymes of the pentose phosphate shunt, glucose-6-phosphate and 6-phosphogluconate dehydrogenase, show a moderate activity which decreases also from the nuclear towards the apical area of the ependymal cells of the SCO. Enzymes of the glycolytic pathway, such as glucosephosphate isomerase, fructose-6-phosphate kinase, fructose-I,6-diphosphate aldolase, glyceraldehyde-3-phosphate and lactate dehydrogenase, are highly active in the SCO and are located mainly in the supranuclear area, too. Fructose-1,6-diphosphatase could not be demonstrated thus indicating that in the SCO the pathway is most probably only glycolytic but not gluconeogenetic. Compared to the ependyma of the ventricular wall and of the choroid plexus, in the SCO the M type subunits of lactate dehydrogenase predominate. Glycolytic enzymes are also very active in the choroid plexus but less in the ciliated ependyma. Compared to the ciliated ependyma and especially to the ependyma of the choroid plexus, the activities of enzymes which are only present in mitochondria (NAD-linked isocitrate dehydrogenase, succinate dehydrogenase, NAD-linked malate dehydrogenase after preextraction, cytochrome oxidase, 3-hydroxybutyrate and glycerolphosphate and glutamate dehydrogenase) are relatively low. Mitochondria are accumulated near the superior pole of the nuclei as well as in the most apical part of the ependymal cells. - The staining pattern of NADP-linked isocitrate and malate dehydrogenase as well as of NADH dehydrogenase suggests that these enzymes are localized both in and out of mitochondria. The extramitochondrial activity of the first two enzymes might be localized in the cytosol. The extramitochondrial activity of NADH dehydrogenase might be localized in the endoplasmic reticulum...
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PMID:Enzymatic organization of the subcommissural organ. 123 49

Previous studies from our laboratory have shown that dehydroepiandrosterone (DHEA), an inhibitor of glucose-6-phosphate dehydrogenase (G6PD), prevents the development of gamma-glutamyltranspeptidase (GGT)-positive foci in the early stages of hepatocarcinogenesis in rats. Since high rates of DNA and cholesterol (CH) synthesis are observed during promotion of carcinogenesis, and mevalonate (MVA), or some other intermediates of CH synthesis, could be mediators of DNA synthesis, we investigated the effect of DHEA on CH synthesis in rat liver during the development of GGT-positive foci. Hepatocarcinogenesis was induced by diethylnitrosamine in female Wistar rats by the Solt-Farber protocol (initiation/selection) with and without phenobarbital treatment. A 15 day treatment with DHEA (0.6% in the diet), started after selection, caused a great fall in labeling and mitotic indices of GGT-positive foci, which was prevented by the simultaneous administration of a mixture of four deoxyribonucleosides (DRNs) of adenine, guanine, cytosine and thymine or four ribonucleosides (RNs) of adenine, guanine, cytosine and uridine, but not by the corresponding bases. DHEA greatly inhibited G6PD activity and the production of ribulose-5-phosphate, without affecting NADPH levels, due to the compensatory increase in malic enzyme and isocitric dehydrogenase activities. Serum lecithin/cholesterol acyltransferase activity underwent a reduction in conditions allowing a rapid growth of GGT-positive tissue (absence of DHEA or presence of DHEA plus DRNs or RNs). Liver slices isolated from DHEA-treated rats showed a rise in CH content, coupled with a 80% fall in the incorporation of labeled acetate, but not of labeled MVA, into CH. A 25 day treatment of rats subjected to initiation/selection, started after the appearance of persistent nodules, caused a 36 and 78% fall in the incorporation, in vivo, of 3H2O into nodular and surrounding liver CH respectively. DRN did not counteract DHEA-induced inhibition on CH synthesis. Thus DHEA inhibits the CH biosynthetic pathway before MVA synthesis, in conditions (presence of DHEA plus DRN/RN) allowing rapid growth of preneoplastic lesions. Therefore, the development of these lesions does not need the synthesis of large amounts of CH and CH metabolites. Thus, the antipromotion effect of DHEA may depend on a decreased availability of pentose phosphates for DNA synthesis.
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PMID:Differential effects of dehydroepiandrosterone and deoxyribonucleosides on DNA synthesis and de novo cholesterogenesis in hepatocarcinogenesis in rats. 168 32

The localization of reduced glutathione in skeletal muscle fibres of patients with inherited or acquired neuromuscular diseases and of subjects with no apparent disease of the neuromuscular system was studied histochemically. In healthy human skeletal muscle fibres, the level of reduced glutathione is higher in aerobic type I fibres than in anaerobic type II fibres. This finding suggests that glutathione in these healthy fibres is held in the reduced state chiefly by the activity of the decarboxylating and NADPH regenerating enzyme NADP(+)-dependent isocitrate dehydrogenase. In diseased muscle fibres, there is generally a positive relationship between the activity of the NADPH producing enzymes glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase and the level of reduced glutathione. This positive relationship suggests that glutathione in these diseased fibres is held in the reduced state chiefly by the activity of both enzymes of the pentose phosphate pathway.
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PMID:The histochemical localization of reduced glutathione in skeletal muscle under different pathophysiological conditions. 171 24

The isolation and characterization of mutant alleles in a regulatory gene affecting NADP(+)-dependent enzymes are described. The locus, mex, is at position 26.5 +/- 0.74 on the X chromosome of Drosophila melanogaster. The newly isolated mutant allele, mex1, is recessive to either the mex allele found in Oregon-R wild-type individuals or that found in the cm v parental stock in which the new mutants were induced. The mex1 mutant allele is associated with statistically significant decreases in malic enzyme (ME) specific activity and ME specific immunologically cross-reacting material (ME-CRM) in newly emerged adult males. During this same developmental stage in males, the NADP(+)-dependent isocitrate dehydrogenase specific activity increases to statistically significant levels. Females of the mex1 mutant strain show statistically significant elevated levels of the pentose phosphate shunt enzymes, glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase. Isoelectric focusing and thermolability comparisons of the active ME from mutant and control organisms indicate that the enzyme is the same. Developmental profiles of mex1 and control strains indicate that this mutant allele differentially modulates the levels of ME enzymatic activity and ME-CRM during development.
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PMID:The isolation and characterization of mutant alleles at a new X-linked locus, mex, affecting NADP(+)-dependent enzymes in Drosophila melanogaster. 190 31

1. Maximal activities of some key enzymes of glycolysis, the pentose phosphate pathway, the tricarboxylic acid cycle and glutaminolysis were measured in homogenates from a variety of normal, neoplastic and suppressed cells. 2. The relative activities of hexokinase and 6-phosphofructokinase suggest that, particularly in neoplastic cells, in which the capacity for glucose transport is high, hexokinase could approach saturation in respect to intracellular glucose; consequently, hexokinase and phosphofructokinase could play an important role in the regulation of glycolytic flux in these cells. 3. The activity of pyruvate kinase is considerably higher in tumorigenic cells than in non-tumorigenic cells and higher in metastatic cells than in tumorigenic cells: for non-tumorigenic cells the activities range from 28.4 to 574, for tumorigenic cells from 899 to 1280, and for metastatic cells from 1590 to 1627 nmol/min per mg of protein. 4. The ratio of pyruvate kinase activity to 2 x phosphofructokinase activity is very high in neoplastic cells. The mean is 22.4 for neoplastic cells, whereas for muscle from 60 different animals it is only 3.8. 5. Both citrate synthase and isocitrate dehydrogenase activities are present in non-neoplastic and neoplastic cells, suggesting that the full complement of tricarboxylic-acid-cycle enzymes are present in these latter cells. 6. In neoplastic cells, the activity of glutaminase is similar to or greater than that of hexokinase, which suggests that glutamine may be as important as glucose for energy generation in these cells.
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PMID:Maximum activities of key enzymes of glycolysis, glutaminolysis, pentose phosphate pathway and tricarboxylic acid cycle in normal, neoplastic and suppressed cells. 230 81

We evaluated the effects of phenobarbital, an inducer, on plasma glucose and serum immunoreactive insulin levels and on hepatic glucose and drug metabolism using an animal model of non-insulin dependent diabetes mellitus. Genetically obese (ob/ob) mice, characterized by hyperglycaemia, hyperinsulinaemia, fatty liver and obesity were selected. The impairment of diabetic state with age was associated with increased activities of NADPH producing enzymes, whereas mixed function oxidase system remained unaltered. Phenobarbital reduced serum immunoreactive insulin and plasma glucose levels and decreased gluconeogenesis. Hepatic glucose phosphorylating enzyme activity increased and glucose releasing enzyme activity decreased. The demand for NADPH in drug oxidation reactions, caused by the induction phenomenon, was reflected in the elevated activities of the NADPH producing enzymes in pentose phosphate pathway and in the activities of isocitrate dehydrogenase and malic enzyme from mitochondrial oxidation reactions. Glucose metabolism of lean littermates indicated that phenobarbital induction normalizes impaired intracellular glucose handling but leaves normal glucose metabolism unaltered. Hepatic glucose production rate was related to plasma glucose, NADPH producing enzyme activities and cytochrome P450 content in the obese and lean mice.
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PMID:Effects of enzyme induction therapy on glucose and drug metabolism in obese mice model of non-insulin dependent diabetes mellitus. 250 Oct 61

Needle biopsies from m. gluteus medius of 22 horses which had suffered from repeated attacks of exertional myopathy were studied at various times after an attack, to determine if metabolic alterations can be demonstrated by enzyme histochemistry. Morphological changes and activity of 25 enzymes were studied. Immediately after onset of an attack, some large rounded fibres with a defect of the oxidative phosphorylation were seen. After some hours these fibres lost their glycolytic enzyme activity, followed by disappearance of mitochondrial enzyme activity with accumulation of Ca2+-containing substances. After 16 h inflammatory cells were found in and around necrotic fibres with a strong activity of acid phosphatase and of the 2 oxidative enzymes of the pentose phosphate pathway. The 4th d after onset of the myopathy regenerating fibres could be observed with a strong activity of both NADPH-producing enzymes of the pentose phosphate pathway. The activity of the decarboxylating enzymes NADP+-malate dehydrogenase and NADP+-isocitrate dehydrogenase was increased in these fibres as well. After some month the studied skeletal muscles were completely normal again. Metabolic interpretations based on the histochemical findings are discussed and compared with those given in literature.
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PMID:[Histochemical changes in skeletal muscles of racehorses susceptible to rhabdomyolysis after exertion. II. Later myopathological and regeneration phenomena]. 253 42


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