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)

Addition of the cell soluble supernatant fraction to an assay medium containing NADPH generating system, mixed function oxidase substrate and microsomes, resulted in a stimulation of drug metabolism ranging from 12-75%. This stimulation was observed only when the supply of DADPH generating system (isocitric dehydrogenase or glucose 6 phosphate dehydrogenase) was insufficient, leading to a NADPH oxidation rate which was greater than the rate of reduction of NADP+ during the oxidation of a drug. Hence, under our assay conditions, the soluble supernate (SS) is only providing sufficient NADPH generator, and possibly relieving inhibition by the generated NADP+. Finally, microsomal lipid peroxidation measurements under these same conditions indicate negligible to no peroxidation activity in the absence of SS.
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PMID:Explanation of the stimulation of microsomal N-demethylation reactions by soluble supernatant fraction. 0 Jul 45

Pig heart NAD-specific isocitrate dehydrogenase is inactivated by reaction with iodoacetate at pH 6.0. Loss of activity can be attributed to the formation of 1-2 mol of carboxymethyl-cysteine per peptide chain. The rate of inactivation is markedly decreased by the combined addition of Mn2+ and isocitrate, but not by alpha-ketoglutarate, the coenzyme NAD or the allosteric activator ADP. The substrate concentration dependence of the decreased rate of inactivation yields a dissociation constant of 1.6 mM for the enzyme-manganous-dibasic isocitrate complex, a value that is 50 times higher than the Km for this substrate. This result suggests that in protecting the enzyme against iodoacetate, isocitrate may bind to a region distinct from the catalytic site. Isocitrate and Mn2+ also prevent thermal denaturation, with an affinity for the enzyme close to that observed for the iodoacetate-sensitive site. The alkylatable cysteine residues may contribute to a manganous-isocitrate binding site which is responsible for stabilizing an active conformation of the enzyme.
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PMID:Alkylation of cysteinyl residues of pig heart NAD-specific isocitrate dehydrogenase by iodoacetate. 0 25

The changes in the rates of citrate biosynthesis and utilization in rat brain, liver, kidney and heart, produced by hypoxia, action of 2,4-DNP and thyreotoxicosis, were compared with changes of some regulatory parameters under the same conditions. The comparison of citrate-synthase activities, citrate levels in tissues and 14C-incorporation from different precursors into citric acid permitted us to establish that the biosynthesis of citrate in brain was more intensive than in other tissues studied. The main source of acetyl-CoA for citrate-synthase reaction in brain is the oxidation of pyruvate. The ratio of adenine nucleotides plays an important role in the control of citrate-synthase activity in brain, where the oxaloacetate control is not as significant as in liver. NAD-specific isocitrate dehydrogenase reaction was found to be the dominant pathway for citrate oxidation in brain: more than 60 percent of brain citrate were oxidized by NAD-ICDH, while less than 10 percent of citric acid were utilized by this enzyme in other tissues studied. The existance of an adenine nucleotide control of NAD-ICDH activity in brain may be an additional mechanism for the regulation of the first steps of energy metabolism in brain.
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PMID:[Mechanisms regulating citric acid metabolism in the brain]. 2 9

The anthraquinone dye alizarine red S produced a unique red crystalline precipitate with oxalosuccinic acid. By chemical, colorometric and spectrophotometric analysis, this red precipitate was found to be a salt composed of these two substances, and to be insoluble in hydrochloric acid above pH = 3.2. Other biologic substances producing a red color without the formation of precipitates showed a disappearance of the red color and resumption of the yellow color of alizarine red S above pH = 3.8. On the basis of these observations, a cytochemical test was developed that may identify the site of oxalosuccinic acid in the cytoplasm of peripheral blood leukocytes. Because of the initimate association of oxalosuccinic acid with isocitric dehydrogenase, the test may also indicate the site of this enzyme as well.
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PMID:Cytochemical identification of oxalosuccinic acid in human leukocytes. 7 37

The cerebral thrombosis of the rat with 35 micrometer labeled microspheres gives infarcted areas easily seen. After 15 min, in these areas, there is no change in NADH diaphorase-, succinic-dehydrogenase-, mono-amino-oxidase-, glucose-6-phosphate-dehydrogenase-, isocitric dehydrogenase-, lactic-dehydrogenase-, ATPase, alpha galactosidase-, acid phospatase activity. After 2, 4, 6 h all these activities diminish in the neuropil but they are preserved in the neurones for diaphorase, succinic-dehydrogenase and mono-amino-oxidase. The margin of infarcted areas shows a strong staining for acid phosphatase. Before 2 h there is not enzymatic changes neither oedema. This experimental model seems trustly and could be developped.
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PMID:[Brain rat histoenzymological changes induced by microsphere injection during ischemia (author's transl)]. 11 18

This study attempted to detect evidence of mitochondrial terminal respiratory components in matrix vesicles isolated from rachitic rat tibial epiphyseal plates. Biochemical assays for cytochrome c oxidase, NAD isocitrate dehydrogenase, NADP isocitrate dehydrogenase and succinate-cytochrome c reductase were negative. Polarimetric determinations revealed that the addition of succinate to matrix vesicles in suspension did not cause any increase in oxygen utilization. Spectrophotometric tracings of deoxycholate-solubilized matrix vesicles showed no characteristic absorption peaks or maxima belonging to any of the cytochrome complex components. Attempts to prepare pyridine hemochromes of cytochrome prosthetic groups from the matrix vesicles were also unsuccessful. The above results indicate that key components of mitochondrial respiratory systems are not detectable in rachitic matrix vesicles. The results are compatible with the interpretation that such vesicles are not derived from mitochondria.
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PMID:Absence of mitochondrial terminal respiratory enzymes in cartilage matrix vesicles. 20 76

This paper reports the time course of development of the intramitochondrial cholesterol side-chain-cleavage activity, cytoplasmic NADP+-dependent isocitric dehydrogenase, malic enzyme and glucose-6-phosphate dehydrogenase during ovarian maturation, using as a model the immature rat ovary stimulated to develop with pharmacological doses of gonadotrophin. These enzymic activities were correlated with increases in ovarian content of DNA, cellular content of adenosin 3':5'-monophosphate, and the levels of plasma progesterone. The plasma progesterone concentrations followed closely the development of the [4-14C]cholesterol side-chain-cleavage which was mimicked by the cytoplasmic isocitric dehydrogenase; both enzymes increased in activity 28 times during the 6 days of this study. There was no correlation between adenosine 3':5'-monophosphate levels and cholesterol side-chain cleavage or progesterone plasma concentrations.
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PMID:Changes in enzyme activities during the artificially stimulated transition from follicular to luteal cell types in rat ovary. 20 54

Starch gel electrophoretic patterns of 26 enzymes (corresponding to 36 gene loci) were examined in hemolysates of erythrocytes from 11 first-trimester and mid-trimester human fetuses (65-138 gestation days). The zymograms of 16 enzymes were identical in fetal and control adult red cells. Six enzymes (enolase, guanylate kinase, lactate dehydrogenase, nucleoside phosphorylase, phosphofructokinase, hexokinase) showed differences in the staining intensity of certain isozyme zones as compared with the controls. Also, the fetal red cell zymograms, in contrast to those of adults, contained the mitochondrial forms of isocitric dehydrogenase and glutamic oxaloacetic transaminase as well as more definite zones of phosphoglucomutase-3. Finally, some of the isozymes of uridine diphosphate kinase in the fetal cells had slightly retarded mobility. These observed differences between fetal and adult red cells could reflect the expression of a different program of protein synthesis in red cells of the fetuses or the epigenetic modifications of isozymes in immature red cells.
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PMID:Isozyme patterns in erythrocytes from human fetuses. 20 89

The NAD-dependent isocitrate dehydrogenase [threo-D(S)-isocitrate:NAD(+) oxidoreductase (decarboxylating); EC 1.1.1.41] from pig heart is a multisubunit enzyme with a molecular weight of approximately 340,000. Electrophoresis of the enzyme in 10% polyacrylamide gels containing sodium dodecyl sulfate reveals two discrete bands with molecular weights of 41,000 and 39,000. The two bands exhibit approximately equal intensity when stained with Coomassie Blue, Amido Black, and Bromophenol Blue, suggesting that these polypeptide chains are present in equimolar quantities in the native enzyme. The same two-band pattern is observed when the sulfhydryl groups of the enzyme are blocked by alkylation with iodoacetate prior to electrophoresis, indicating that sulfhydryl oxidation is not responsible for the observed heterogeneity. Each of the subunits appears as a single band when eluted from the gel and again subjected to electrophoresis under the same conditions. Isocitrate dehydrogenase contains a total of 41 lysine and arginine residues per average subunit of 40,000 daltons. The observation of approximately 80 peptides upon paper chromatography and high voltage electrophoresis of tryptic digests of the enzyme is consistent with the existence of two distinct polypeptide chains. Dansylation yields two NH(2)-terminal amino acid derivatives: dansyl-phenylalanine and dansyl-alanine. It is concluded that the NAD-specific isocitrate dehydrogenase is composed of equal numbers of two nonidentical subunits.
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PMID:Evidence for the presence of two nonidentical subunits in NAD-dependent isocitrate dehydrogenase of pig heart. 20 34

The molecular weight of NAD-specific isocitrate dehydrogenase, purified from baker's yeast, has been studied by molecular sieve chromatography. By elution of the enzyme from columns of Sepharose 6B with 0.05 M phosphate buffer, pH 7.6, a mol. wt of 151,000 was measured. Higher values of the mol. wt were measured in presence of the following ligands (mol. wt in parentheses): the substrate, isocitrate (224,000); the activators, citrate (203,000) and AMP (275,000); the inhibitor, NaCl (360,000). A mol. wt of 337,000 was measured when AMP, which antagonizes the inhibition by chloride, was present together with NaCl. The results indicate the absence of a correlation between the aggregation form of the enzyme in presence of the ligands and the effects of these ligands on the enzyme activity.
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PMID:Polymeric forms of yeast nicotinamide-adenine dinucleotide-specific isocitrate dehydrogenase in the presence of various ligands. 20 7


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