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:1.4.3.11 (glutamate dehydrogenase)
4,437 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Toxic doses of zinc and cadmium inhibit shoot growth but increase the capacity of several leaf enzymes in dwarf beans (Phaseolus vulgaris L.). Both effects were studied as a function of the metal concentration applied to the plant. There was a linear relationship between the metal content of the primary leaf and the nutrient solution. When leaf metal content exceeded a toxic threshold value, shoot growth became inhibited and an increase in capacity of the following enzymes was measured in the leaf: glucose-6-phosphate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase, malic enzyme, glutamate-oxaloacetate transminase, peroxidase. The threshold values were similar for growth inhibition as well as for enzyme capacity induction. Both effects were strongly correlated to each other, especially under conditions of toxic zinc treatment. Measurement of enzyme capacity might therefore provide a useful criterion for the evaluation of the phytotoxicity of soils, contaminated by zinc and/or cadmium.
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PMID:Induction of enzyme capacity in plants as a result of heavy metal toxicity: dose-response relations in Phaseolus vulgaris L., treated with zinc and cadmium. 1509 10

The properties of extracellular L-glutamate oxidase, isolated and purified from Streptomyces sp. Z-11-6 (specific activity, 50.8 U/mg protein; yield, 40%), were studied. A photometrical method of determination of activities of alanine- and aspartate aminotransferases, based on the use of the L-glutamate oxidase and peroxidase, has been developed. This method is sufficiently sensitive to be used for the determination of aminotransferase activities in biological fluids. The presence of other amino acids did not interfere with the analysis and had no effect on the results of determination.
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PMID:[Properties and prospects of practical use of extracellular L-glutamate oxidase from Streptomyces sp. Z-11-6]. 1512 94

Hydrogel-coated microsensors based on carbon fiber electrodes (CFEs) are promising tools for in vivo analysis of endogeneous compounds such as glutamate. However, their construction generally depends on manual fabrication, which often results in poor reproducibility. The aim of this study was to improve the reproducibility and performance of glutamate microsensors. CFEs (10 microm diameter, 300-500 microm long) were coated with a cross-linked redox-polymer hydrogel containing l-glutamate oxidase, horseradish peroxidase and ascorbate oxidase. Various parameters that are likely to influence the reproducibility of the glutamate microsensors were studied. It appeared that the most crucial step in determining the microsensor performance is the manual hydrogel-application procedure. To control this procedure an automated dipcoater was constructed, which allowed mechanical application of the hydrogel on the CFE under standardized conditions. Significant improvements in performance were seen when the CFEs were dipcoated for 10 min at 37 degrees C. Further improvements were obtained when the automated hydrogel application was combined with other cross-link methods, such as electrodeposition and electrostatic complexation. A crucial factor in determining the microsensor performance is the hydrogel thickness. Microscopic observations revealed that, despite the use of an automated dipcoater, the layer thickness was not constant. By combining the automated dipcoat technique with amperometry, the layer thickness could be indirectly monitored and controlled, which resulted in significant improvements of the reproducibility of the sensors.
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PMID:Improving the reproducibility of hydrogel-coated glutamate microsensors by using an automated dipcoater. 1558 41

The simultaneous detection of nitric oxide and glutamate using an array of individually addressable electrodes, in which the individual electrodes in the array were suitably modified with a highly sensitive nitric oxide sensing chemistry or a glutamate oxidase/redox hydrogel-based glutamate biosensor is presented. In a sequence of modification steps one of the electrodes was covered first with a positively charged Ni porphyrin entrapped into a negatively charged electrodeposition paint followed by the manual modification of the second working electrode by a bienzyme sensor architecture based on crosslinked redox hydrogels with entrapped peroxidase and glutamate oxidase. Adherently growing C6-glioma cells were grown on membrane inserts and placed in close distance to the modified sensor surfaces. The current responses recorded at each electrode after stimulation of glutamate and NO release by means of K+ and bradykinin clearly demonstrate the ability of the individual electrode in the array to detect the analyte towards which its sensitivity and selectivity was targeted without interference from the neighbouring electrode or other analytes present in the test mixture.
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PMID:Simultaneous detection of the release of glutamate and nitric oxide from adherently growing cells using an array of glutamate and nitric oxide selective electrodes. 1562 9

Amperometric hydrogel-coated glutamate microsensors form a promising concept to detect glutamate levels directly in brain tissue. These microsensors are constructed by coating a carbon fiber electrode (CFE) (10 microm diameter; 300-500 microm long) with a five-component redox-hydrogel, in which L-glutamate oxidase, horseradish peroxidase, and ascorbate oxidase are wired via poly(ethylene glycol) diglycidyl ether to an osmium-containing redox polymer. Coating with a thin Nafion film completes the construction. Prior to use in vivo, a reliable and reproducible construction of microsensors with a high performance is required. For an optimal microsensor performance, the balance between the five individual hydrogel components is critical. However, due to their small size, hydrogel application to CFE's need to be performed by dip-coating. Dip-coating is a difficult procedure to control and does not allow individual application of hydrogel constituents. To improve the microsensor construction and to better control the dip-coating procedure, we have recently developed an automated device. Throughout this study, automatic dip-coating was performed with premixed solutions, in which the amount of a single component was varied. This allowed us to optimize the hydrogel composition, which resulted in a significant improvement of the microsensor properties in terms of sensitivity, current density, linearity, detection limit, and interference by ascorbic acid.
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PMID:Improving glutamate microsensors by optimizing the composition of the redox hydrogel. 1613 Oct 61

The activity of 10 enzymes separated by acrylamide disc gel electrophoresis of leaf and stem extracts from Dianthus grown under summer and winter conditions was studied. While banding was constant and highly reproducible under each environment, differences between the 3 cultivars and between the tissues were evident. No significant differences in the isozyme patterns of glutamate dehydrogenase, 6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, malate dehydrogenase, and catalase were observed between the 2 environments. Loss of activity was observed under winter conditions with amylase and lactate dehydrogenase and loss of certain isozymic components was evident with acid phosphatase and esterase. Prominent changes were observed in peroxidase isozymes, the hardy cultivars developing additional isozymic components under winter conditions. Only minor changes in the total protein banding were seen. The enzymes showed considerable stability in those tissues killed by the freezing conditions.
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PMID:Plant Leaf and Stem Proteins. II. Isozymes and Environmental Cabbage. 1665 48

Glutamate microsensors form a promising analytical tool for monitoring neuronally derived glutamate directly in the brain. However, when a microsensor is implanted in brain tissue, many factors can diminish its performance. Consequently, a thorough characterization and evaluation of a microsensor is required concerning all factors that may possibly be encountered in vivo. The present report deals with the validation of a hydrogel-coated glutamate microsensor. This microsensor is constructed by coating a carbon fiber electrode (10-microm diameter; 300-500 microm long) with a five-component redox hydrogel, in which L-glutamate oxidase, horseradish peroxidase, and ascorbate oxidase are wired via poly(ethylene glycol) diglycidyl ether to an osmium-containing redox polymer. A thin Nafion coating completes the construction. Although this microsensor was previously used in vivo, information concerning its validation is limited. In the present study, attention was given to its selectivity, specificity, calibration, oxygen dependency, biofouling, operating potential dependency, and linear range. In addition, successful microsensor experiments in microdialysate, in vitro (in organotypic hippocampal slice cultures), and in vivo (in anesthesized rats) are shown.
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PMID:Evaluation of hydrogel-coated glutamate microsensors. 1668 39

An ex vivo system for simultaneous detection of nitric oxide (NO) and L-glutamate using integrated dual 250 microm platinum disk electrodes modified individually with suitable sensing chemistries has been developed. One of the sensors was coated with an electrocatalytic layer of Ni tetrasulfonate phthalocyanine tetrasodium salt (Ni-TSPc) covered by second layer of Nafion, which stabilises on the one hand the primary oxidation product NO(+) and prevents interferences from negatively charged compounds such as NO(2)(-). For glutamate determination, the second electrode was modified with a crosslinked redox hydrogel consisting of Os complex modified poly(vinylimidazol), glutamate oxidase and peroxidase. A manual x-y-z micromanipulator on top of an inverted optical microscope was used to position the dual electrode sensor at a defined distance of 5 microm from a cell population under visual control. C6 glioma cells were stimulated simultaneously with bradykinin or VEGF to release NO while KCl was used to invoke glutamate release. For evaluation of the glutamate sensors, in some experiments HN10 cells were used. To investigate the sensitivity and reliability of the system, several drugs were applied to the cells, e.g. Ca(2+)-channel inhibitors for testing Ca(2+)-dependence of the release of NO and glutamate, rotenone for inducing oxidative stress and glutamate antagonists for analysing glutamate release. With these drugs the NO and glutamate release was modulated in a similar way then expected from previously described systems or even in-vivo measurements. We therefore conclude that our system is suitable to analyse stress-induced mechanisms in cell lines.
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PMID:Simultaneous detection of L-glutamate and nitric oxide from adherently growing cells at known distance using disk shaped dual electrodes. 1673 97

Medical sensing systems using isolated or intact glutamate receptor (GluR) ion channels and glutamate oxidase (GluOx) are discussed for L-glutamate, one of the principal neurotransmitter in the central nervous systems of mammalian brain, and related agonists. The GluR-based sensing system used for the evaluation of signal transduction ability of GluR channels demonstrate that the agonist selectivity based on the signal transduction ability is not parallel to that of the binding assay. On the other hand, the appropriate design of the enzyme system, namely glutamate oxidase (GluOx), in combination with horseradish peroxidase (HRP), enables to real-time monitoring of L-glutamate in vivo and in vitro and also to visualize its release in submerged, acute mouse hippocampal slices.
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PMID:Receptors and enzymes for medical sensing of L-glutamate. 1707 9

There is an increasing interest in new strategies to detect neurotransmitters released from nerve cells in real time for brain science, drug assessment, and so on. Previously we reported real-time monitoring of dopamine release from nerve model cells by enzyme-catalyzed luminescence measurement with tyramine oxidase and peroxidase. In the present study, the system was modified with glutamate oxidase instead of tyramine oxidase to detect L-glutamate sensitively ( approximately 10 nM) and rapidly with high temporal resolution (<1 s). We applied this modified method successfully to perform real-time monitoring of L-glutamate release from brain model cell (C6 glioma cell) using a luminescence plate reader upon stimulation with high concentration of KCl (>10 mM) or 5-hydroxytryptamine (>1 microM). The measurement solution was not toxic and therefore the L-glutamate release from the cell was measured by the second stimulation after exchanging the measurement solution. We conclude that the developed monitoring system is suitable for real-time detection of dynamic L-glutamate release from nerve cells in vitro and will be suitable for application in assessment of drugs acting on the nervous system.
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PMID:Real-time detection of L-glutamate released from C6 glioma cells using a modified enzyme-luminescence method. 1784


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