Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:1.6.99.3 (diaphorase)
 5,903 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Twelve enzymes from mature pollen grains of maize were separated by two-dimensional polyacrylamide gel electrophoresis (2-D PAGE). The separation in the second dimension was both in the presence and absence of sodium dodecyl sulfate (SDS). Ten of the investigated enzymes lost activity after separation in the presence of SDS, but those of esterases and acid phosphatase could be recovered. On the other hand, 2-D electrophoresis without SDS is suitable for the analysis of maize pollen pectinesterase, malate dehydrogenase, glutamic-oxalacetic transaminase, diaphorase, superoxide dismutase, and phosphoglucose isomerase. 1-D PAGE and isoelectric focusing (IEF) are sufficient to analyze glucose-6-phosphate dehydrogenase, alcohol dehydrogenase, shikimic dehydrogenase, and glutamate dehydrogenase. The possibility of applying 2-D electrophoresis for the analysis of enzymes from single stigma and stigma exudate is dicussed.
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PMID:Maize pollen enzymes after two-dimensional polyacrylamide gel electrophoresis in the presence or absence of sodium dodecyl sulfate. 1182 13

Enzymatic reduction of physiological Fe(III) complexes of the "labile iron pool" has not been studied so far. By use of spectrophotometric assays based on the oxidation of NAD(P)H and formation of [Fe(II) (1,10-phenanthroline)3]2+ as well as by utilizing electron paramagnetic resonance spectrometry, it was demonstrated that the NAD(P)H-dependent flavoenzyme lipoyl dehydrogenase (diaphorase, EC 1.8.1.4) effectively catalyzes the one-electron reduction of Fe(III) complexes of citrate, ATP, and ADP at the expense of the co-enzymes NAD(P)H. Deactivated or inhibited lipoyl dehydrogenase did not reduce the Fe(III) complexes. Likewise, in the absence of NAD(P)H or in the presence of NAD(P)+, Fe(III) reduction could not be detected. The fact that reduction also occurred in the absence of molecular oxygen as well as in the presence of superoxide dismutase proved that the Fe(III) reduction was directly linked to the enzymatic activity of lipoyl dehydrogenase and not mediated by O2. Kinetic studies revealed different affinities of lipoyl dehydrogenase for the reduction of the low molecular weight Fe(III) complexes in the relative order Fe(III)-citrate > Fe(III)-ATP > Fe(III)-ADP (half-maximal velocities at 346-485 microm). These Fe(III) complexes were enzymatically reduced also by other flavoenzymes, namely glutathione reductase (EC 1.6.4.2), cytochrome c reductase (EC 1.6.99.3), and cytochrome P450 reductase (EC 1.6.2.4) with somewhat lower efficacy. The present data suggest a (patho)physiological role for lipoyl dehydrogenase and other flavoenzymes in intracellular iron metabolism.
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PMID:Reduction of Fe(III) ions complexed to physiological ligands by lipoyl dehydrogenase and other flavoenzymes in vitro: implications for an enzymatic reduction of Fe(III) ions of the labile iron pool. 1296 36

The nitrate reductase in the mature root extract of 3-day maize (Zea mays) seedlings was relatively labile in vitro. Insoluble polyvinylpyrrolidone used in the extraction medium produced only a slight increase in the stability of the enzyme. Mixing the mature root extract with that of the root tip promoted the inactivation of nitrate reductase in the latter. The inactivating factor in the mature root was separated from nitrate reductase by (NH(4))(2)SO(4) precipitation. Nitrate reductase was found in the 40% (NH(4))(2)SO(4) precipitate, while the inactivating factor was largely precipitated by 40 to 55% (NH(4))(2)SO(4). The latter fraction of the mature root inactivated the nitrate reductase isolated from the root tip, mature root, and scutellum. The inactivating factor, which has a Q(10) 15 to 25 C of 2.2, was heat labile, and hence has been designated as a nitrate reductase inactivating enzyme. The reduced flavin mononucleotide nitrate reductase was also inactivated, while an NADH cytochrome c reductase in nitrate-grown seedlings was inactivated but at a slower rate. The inactivating enzyme had no influence on the activity of nitrite reductase, glutamate dehydrogenase, xanthine oxidase, and isocitrate lyase. The activity of the nitrate reductase inactivating enzyme was not influenced by nitrate and was also found in the mature root of minus nitrate-grown seedlings.
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PMID:A nitrate reductase inactivating enzyme from the maize root. 1665 31

The mitochondrial membrane potential measured in isolated rat kidney mitochondria and in digitonin-permeabilized MDCK type II cells pre-energized with succinate, glutamate, and/or malate was reduced by micromolar diclofenac dose-dependently. However, ATP biosynthesis from glutamate/malate was significantly more compromised compared to that from succinate. Inhibition of the malate-aspartate shuttle by diclofenac with a resultant decrease in the ability of mitochondria to generate NAD(P)H was demonstrated. Diclofenac however had no effect on the activities of NADH dehydrogenase, glutamate dehydrogenase, and malate dehydrogenase. In conclusion, decreased NAD(P)H production due to an inhibition of the entry of malate and glutamate via the malate-aspartate shuttle explained the more pronounced decreased rate of ATP biosynthesis from glutamate and malate by diclofenac. This drug, therefore affects the bioavailability of two major respiratory complex I substrates which would normally contribute substantially to supplying the reducing equivalents for mitochondrial electron transport for generation of ATP in the renal cell.
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PMID:Action of diclofenac on kidney mitochondria and cells. 1689 Feb 7

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

Changes in the maximal rate of some cerebral enzymatic activities related to energy transduction (lactate dehydrogenase; citrate synthase and malate dehydrogenase; total NADH-cytochrome c reductase and cytochrome oxidase) as well as both glutamate dehydrogenase and acetylcholine esterase were assayed in the purified mitochondrial fraction or in crude synaptosomal fraction from cerebral cortex. The evaluations were performed in rats before and after a postdecapitative normothermic ischemia of 5, 10, 20 and 40 min duration. The ischemic damage resulted in a decrease in the activity of mitochondrial malate dehydrogenase and total NADH-cytochrome c reductase, and of synaptosomal acetylcholine esterase. The biochemical evaluations were performed also after an i.p. pretreatment with vincamine, trimetazidine and suloctidil (50 mg/kg). The drugs induced different changes in enzyme activities as a function of the ischemia duration. These various interferences are discussed with regard to the possible drugs mode of action.
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PMID:The effect of ischemia and pharmacological treatment evaluated on synaptosomes and purified mitochondria from rat cerebral cortex. 2104 37


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