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:1.1.1.37 (malate dehydrogenase)
4,591 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Intracellular free Zn(2+) is elevated in a variety of pathological conditions, including ischemia-reperfusion injury and Alzheimer's disease. Impairment of mitochondrial respiration is also associated with these pathological conditions. To test whether elevated Zn(2+) and impaired respiration might be linked, respiration of isolated rat liver mitochondria was measured after addition of Zn(2+). Zn(2+) inhibition (K(i)(app) = approximately 1 micrometer) was observed for respiration stimulated by alpha-ketoglutarate at concentrations well within the range of intracellular Zn(2+) reported for cultured hepatocytes. The bc(1) complex is inhibited by Zn(2+) (Link, T. A., and von Jagow, G. (1995) J. Biol. Chem. 270, 25001-25006). However, respiration stimulated by succinate (K(i)(app) = approximately 6 micrometer) was less sensitive to Zn(2+), indicating the existence of a mitochondrial target for Zn(2+) upstream from bc(1) complex. Purified pig heart alpha-ketoglutarate dehydrogenase complex was strongly inhibited by Zn(2+) (K(i)(app) = 0.37 +/- 0.05 micrometer). Glutamate dehydrogenase was more resistant (K(i)(app) = 6 micrometer), malate dehydrogenase was unaffected, and succinate dehydrogenase was stimulated by Zn(2+). Zn(2+) inhibition of alpha-ketoglutarate dehydrogenase complex required enzyme cycling and was reversed by EDTA. Reversibility was inversely related to the duration of exposure and the concentration of Zn(2+). Physiological free Zn(2+) may modulate hepatic mitochondrial respiration by reversible inhibition of the alpha-ketoglutarate dehydrogenase complex. In contrast, extreme or chronic elevation of intracellular Zn(2+) could contribute to persistent reductions in mitochondrial respiration that have been observed in Zn(2+)-rich diseased tissues.
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PMID:Zn2+ inhibits alpha-ketoglutarate-stimulated mitochondrial respiration and the isolated alpha-ketoglutarate dehydrogenase complex. 1078 56

Heat shock proteins (hsp), hsp60 and hsp10, are involved in the folding of imported mitochondrial proteins and the refolding of denatured proteins after stress. We examined whether hsp10 can reduce myocyte death by its mitochondrial function or by interacting with cytoplasmic signaling pathways. Overexpression of hsp10 by adenoviral infection decreased myocyte death induced by hydrogen peroxide, sodium cyanide, and simulated ischemia and reoxygenation (SI/RO). We generated an adenoviral vector coding for a temperature-sensitive mutant hsp10 protein (P34H), incapable of cooperatively refolding denatured malate dehydrogenase with hsp60. Overexpression of the hsp10 mutant potentiated SI/RO-induced myocyte death. Analysis of electron transport chain function revealed increased Complex I capacity with hsp10 overexpression, whereas hsp10(P34H) overexpression decreased Complex II capacity. Hsp10 overexpression preserved both Complex I and II function after SI/RO. Examination of the Ras GTP-ase signaling pathway indicated that inhibition of Ras was required for protection by hsp10. Constitutive activation of Ras abolished the effects afforded by hsp10 and hsp10(P34H). Hsp10 overexpression inactivated Raf, ERK, and p90Ribosomal kinase (p90RSK) before and after SI/RO. Our results suggest that complex mechanisms are involved in the protection by hsp10 against SI/RO-induced myocyte death. This mechanism may involve the hsp10 mobile loop and attenuation of the Ras GTP-ase signaling pathway.
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PMID:Myocyte protection by 10 kD heat shock protein (Hsp10) involves the mobile loop and attenuation of the Ras GTP-ase pathway. 1505 67

Experimental ishemia of rat myocardium was accompanied by increase of light sum (S) and maximal intensity (Imax) of chemiluminescence, amount of a malonic dialdehyde and conjugated dienes in cytoplasmic fraction. The activity of NADP-dependent malate dehydrogenase (EC 1.1.1.82; NADP-MDH) was 1.6 times higher in rat heart under ischemia. NADP-MDH was purified from normal and ischemia-exposed rat myocardium. Using NADP-MDH purified enzyme preparations the values of Hill coefficient for oxaloacetate (1.83 +/- 0.07 and 1.50 +/- 0.10) and Km for NADPH (0.058 +/- 0.003 and 0.096 +/- 0.004 mM) were determined for the enzyme at norm and under ischemia respectively. Effects of Fe2+, Ca2+, Cu2+ ions, H2O2, oxidized and reduced glutathione, adenine nucleotides influence on functioning of NADP-MDH from rat heart at norm and under ischemic conditions have been investigated.
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PMID:[Free-radical oxidation and regulation of cytoplasmic NADP-dependent malate dehydrogenase in rat cardiomyocytes at norm and under ischemia]. 1610 94

NAD-dependent malate dehydrogenase activity decreased by 2.7 times in the myocardium of rats with experimental ischemia. Cytoplasmic NAD-dependent malate dehydrogenase from intact and ischemic rat heart was purified by 91.4 and 95.5 times. We compared kinetic characteristics and regulation of enzyme activity by Fe(2+), Cu(2+), Ca(2+), hydrogen peroxide, and glutathione under normal and pathological conditions.
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PMID:Function of cytoplasmic NAD-dependent malate dehydrogenase from rat myocardium under conditions of ischemia. 1625 12

We used proteomics to detect regional differences in protein expression levels from mitochondrial fractions of control, ischemia-reperfusion (IR), and ischemic preconditioned (IPC) rabbit hearts. Using 2-DE, we identified 25 mitochondrial proteins that were differentially expressed in the IR heart compared with the control and IPC hearts. For three of the spots, the expression patterns were confirmed by Western blotting analysis. These proteins included 3-hydroxybutyrate dehydrogenase, prohibitin, 2-oxoglutarate dehydrogenase, adenosine triphosphate synthases, the reduced form of nicotinamide adenine dinucleotide (NADH) oxidoreductase, translation elongation factor, actin alpha, malate dehydrogenase, NADH dehydrogenase, pyruvate dehydrogenase and the voltage-dependent anion channel. Interestingly, most of these proteins are associated with the mitochondrial respiratory chain and energy metabolism. The successful use of multiple techniques, including 2-DE, MALDI-TOF-MS and Western blotting analysis demonstrates that proteomic analysis provides appropriate means for identifying cardiac markers for detection of ischemia-induced cardiac injury.
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PMID:Potential biomarkers for ischemic heart damage identified in mitochondrial proteins by comparative proteomics. 1640 59

The catalytic properties of mitochondrial and cytoplasmic isoenzymes of NAD-dependent brain malate dehydrogenase (MDH) were studied under hypoxic or ischemic conditions. Hypoxia was modeled in animals in pressure chamber, while ischemia was achieved via bilateral ligation of common carotic arteries. The properties of MDH in mitochondria of rat brain were studied; they were significantly different from those of MDH purified from bovine brain. The study revealed the importance of mitochondrial membranes for the regulation of malate dehydrogenase catalytic properties in brain mitochondria. Cerebral ischemia changes mitochondrial malate dehydrogenase significantly, which demonstrates disorder in MDH-membrane interaction. Cytoplasmic enzyme displays high activity and stability of its catalytic properties. Under cerebral hypoxia or ischemia catalytic properties of cytoplasmic malate dehydrogenase change only slightly, maintaining enzyme activity at a constantly high level.
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PMID:[Properties of NAD-dependent brain enzymes under the conditions of hypoxia and ischemia]. 1739 58

The activity of lactate dehydrogenase (LDG), malate dehydrogenase (MDG), concentrations of lactic acid and lipid peroxidation (LPO) products in the blood serum and urine were estimated in 119 patients with acute pyelonephritis (70 cases of serous and 49 cases of purulent). The results of the study showed that acute pyelonephritis patients have activated anaerobic glycolysis. Ischemia leads to accumulation of lactic acid, activation of LPO. Significant differences between the groups of patients reflect strong influence of renaltissue ischemia on activity of systemic metabolic processes and metabolism in renal parenchyma. Standard infusion therapy was given to 30 patients with acute purulent pyelonephritis. 19 patients received solution of succinic acid reamberin. On day 4 of reamberin therapy plasma and urine activity of LDG and MDG attenuated, lactic acid concentration decreased, content of dienic conjugates was close to normal. Patients on reamberin treatment exhibited earlier relief of endogenic intoxication and improvement of blood count. Thus, succinic acid drugs reduce renal ischemia, improve a course of postoperative period in patients with acute purulent pyelonephritis.
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PMID:[Succinic acid infusions for correction of renal ischemia in patients with acute purulent pyelonephritis]. 1864 57

We applied a combined proteomic and metabolomic approach to obtain novel mechanistic insights in PKCvarepsilon-mediated cardioprotection. Mitochondrial and cytosolic proteins from control and transgenic hearts with constitutively active or dominant negative PKCvarepsilon were analyzed using difference in-gel electrophoresis (DIGE). Among the differentially expressed proteins were creatine kinase, pyruvate kinase, lactate dehydrogenase, and the cytosolic isoforms of aspartate amino transferase and malate dehydrogenase, the two enzymatic components of the malate aspartate shuttle, which are required for the import of reducing equivalents from glycolysis across the inner mitochondrial membrane. These enzymatic changes appeared to be dependent on PKCvarepsilon activity, as they were not observed in mice expressing inactive PKCvarepsilon. High-resolution proton nuclear magnetic resonance ((1)H-NMR) spectroscopy confirmed a pronounced effect of PKCvarepsilon activity on cardiac glucose and energy metabolism: normoxic hearts with constitutively active PKCvarepsilon had significantly lower concentrations of glucose, lactate, glutamine and creatine, but higher levels of choline, glutamate and total adenosine nucleotides. Moreover, the depletion of cardiac energy metabolites was slower during ischemia/reperfusion injury and glucose metabolism recovered faster upon reperfusion in transgenic hearts with active PKCvarepsilon. Notably, inhibition of PKCvarepsilon resulted in compensatory phosphorylation and mitochondrial translocation of PKCdelta. Taken together, our findings are the first evidence that PKCvarepsilon activity modulates cardiac glucose metabolism and provide a possible explanation for the synergistic effect of PKCdelta and PKCvarepsilon in cardioprotection.
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PMID:Proteomic and metabolomic analysis of cardioprotection: Interplay between protein kinase C epsilon and delta in regulating glucose metabolism of murine hearts. 1902 23

Ca2+ accumulation and Ca2+ overloading in mitochondria are responsible for the cell abnormality associated with ischemia and reperfusion injury. The present study was aimed at evaluating the efficacy of the Ca2+ channel blocker amlodipine on the mitochondrial Ca2+ accumulation, mitochondrial antioxidant status and mitochondrial respiratory enzymes in ischemia and reperfusion (I/R) induced liver injury. I/R injury induced mitochondrial damage in rats was assessed in terms of the decrease in activities (p < 0.05) of respiratory marker enzymes (malate dehydrogenase, succinate dehydrogenase and NADH dehydrogenase), mitochondrial antioxidant enzymes (glutathione, superoxide dismutase, catalase), and significant increase (p < 0.05) in the level of lipid peroxidation (LPO) and Ca2+ content.Mitochondrial damage was confirmed by transmission electron microscopic (TEM) examination. Pretreatment with amlodipine effectively counteracted the alteration in mitochondrial enzymes induced by ischemia-reperfusion liver damage. TEM study confirms the restoration of cellular normalcy and the cytoprotective role of amlodipine against I/R induced hepatic injury. On the basis of our findings it may be concluded that amlodipine not only possesses Ca2+ channel antagonist properties but it may also reduce the extent of mitochondrial damage by its antioxidant activity.
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PMID:Protective role of the calcium channel blocker amlodipine against mitochondrial injury in ischemia and reperfusion injury of rat liver. 1910 76

The effect of ageing and the relationships between the catalytic properties of enzymes linked to Krebs' cycle, electron transfer chain, glutamate and aminoacid metabolism of cerebral cortex, a functional area very sensitive to both age and ischemia, were studied on mitochondria of adult and aged rats, after complete ischemia of 15 minutes duration. The maximum rate (Vmax) of the following enzyme activities: citrate synthase, malate dehydrogenase, succinate dehydrogenase for Krebs' cycle; NADH-cytochrome c reductase as total (integrated activity of Complex I-III), rotenone sensitive (Complex I) and cytochrome oxidase (Complex IV) for electron transfer chain; glutamate dehydrogenase, glutamate-oxaloacetate-and glutamate-pyruvate transaminases for glutamate metabolism were assayed in non-synaptic, perikaryal mitochondria and in two populations of intra-synaptic mitochondria, i.e., the light and heavy mitochondrial fraction. The results indicate that in normal, steady-state cerebral cortex, the value of the same enzyme activity markedly differs according (a) to the different populations of mitochondria, i.e., non-synaptic or intra-synaptic light and heavy, (b) and respect to ageing. After 15 min of complete ischemia, the enzyme activities of mitochondria located near the nucleus (perikaryal mitochondria) and in synaptic structures (intra-synaptic mitochondria) of the cerebral tissue were substantially modified by ischemia. Non-synaptic mitochondria seem to be more affected by ischemia in adult and particularly in aged animals than the intra-synaptic light and heavy mitochondria. The observed modifications in enzyme activities reflect the metabolic state of the tissue at each specific experimental condition, as shown by comparative evaluation with respect to the content of energy-linked metabolites and substrates. The derangements in enzyme activities due to ischemia is greater in aged than in adult animals and especially the non-synaptic and the intra-synaptic light mitochondria seems to be more affected in aged animals. These data allow the hypothesis that the observed modifications of catalytic activities in non-synaptic and intra-synaptic mitochondrial enzyme systems linked to energy metabolism, amino acids and glutamate metabolism are primary responsible for the physiopathological responses of cerebral tissue to complete cerebral ischemia for 15 min duration during ageing.
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PMID:Effect of ageing and ischemia on enzymatic activities linked to Krebs' cycle, electron transfer chain, glutamate and aminoacids metabolism of free and intrasynaptic mitochondria of cerebral cortex. 1949 70


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