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:1.4.1.2 (glutamate dehydrogenase)
4,380 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Mammalian and avian muscles were examined histochemically and biochemically to determine the relative contribution of membrane bound (mitochondrial and sarcotubular) ATPases under the same conditions employed for myofibrillar ATPase. For histochemically investigated Ca+(+)-ATPase activity following incubation at pH 9.4 according to the calcium-citro-phosphate technique, avian muscle displayed distinct mitochondrial localization in both dark and light staining fibres. However, mitochondrial localization did not occur in mammalian muscle fibres. Pretreatment of unfixed frozen sections with ouabain, cyanide and acetone did not prevent the reticular distribution in avian muscle fibres. The present study demonstrates that "myofibrillar" localization is achieved by the Ca+(+)-precipitation technique: provided frozen sections are pretreated with cold acetone, fixed in a fixative containing oligomycin or azide and then incubated in a medium containing glycine-NaO H as buffer. Mitochondria prepared by successive mechanical homogenization or by Nagarse treatment plus 2 min homogenization develop different ATPase activities at pH 9.4 7.4 6.0 and 4.35 as well as stimulation by 70 mM Ca++ at these pHs compared to those ATPase activities in the homogenate of mixed hamster hind leg muscles. Glycerol-3-phosphate dehydrogenase and creatine kinase (both located at the outer surface of the inner mitochondrial membrane) and succinate dehydrogenase and glutamate dehydrogenase (localized at the inner mitochondrial membrane and in the matrix resp.) also show different activities in both mitochondria preparations indicating different membrane properties of both mitochondria. Evidence is obtained that using the calcium-citro-phosphate technique at pH 9.4 oligomycin-sensitive and -insensitive ATPases are activated by Ca++ in both mitochondria preparations. Since in muscle homogenate less than 10% of Ca+(+)-stimulated ATPase activity is oligomycin-sensitive, mitochondrial ATPase exhibit only a small portion of total ATPase from mixed hamster hind leg muscles.
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PMID:Histochemical and biochemical investigations of adenosine triphosphatase in vertebrate mixed muscles. 4 33

The effects of exposure of glial cells in primary culture and in continuous line (clone NN) to pentobarbital over various periods of time on cellular respiration and activities of enzymes involved in carbohydrate metabolism were studied. The results obtained in glial cells in primary culture were qualitatively identical to those obtained in glial cells in clonal line (NN). Both types of glial cells were shown to develop biochemical tolerance to pentobarbital as defined by an attenuated response to the depressant effects of a challenging dose of pentobarbital on cellular respiration in barbiturate-cultivated cells compared to those grown in drug-free medium. The biochemical tolerance was evident in the presence of glucose and succinate but not malate as substrate. This tolerance to pentobarbital was accompanied by increased activities of hexokinase, glucose-6-phosphate dehydrogenase, succinate dehydrogenase, and glutamate dehydrogenase and by a marked increase in the number of glial cell mitochondria as observed in electron micrographs. The results are interpreted to indicate a compensation of glial cells to the continuous presence of PB by an accelerated glucose uptake and metabolism, an accelerated metabolism of succinate, and an increased mitochondrial activity.
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PMID:Development and mechanism of barbiturate tolerance in glial cell cultures. 15 11

A tetrazolium staining medium incorporated in a gel has been used in a histochemical study of enzymes in thin sections of heart muscle. Formazan distribution patterns given by mitochondrial enzymes were inconsistent with the location of these enzymes revealed by the extraction of whole tissue. Similar stain distributions were given by lactate dehydrogenase, glutamate oxaloacetate transaminase and glutamate dehydrogenase. The distribution given by succinate dehydrogenase was not the same as that given by cytochrome oxidase stained by a different technique. Alcohol dehydrogenase added to the tissue assumed a distribution which suggested some adsorption of the enzyme to the tissue. But experiments suggested that this enzyme was not firmly bound to muscle proteins in the manner of some glycolytic enzymes.
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PMID:Localization in cardiac muscle of some enzymes related to glutamate metabolism. 16 67

Rat liver mitochondrial enzyme activities were measured after exposing the animals to the atmospheric pressure of 380 mm Hg for 5 h and 14 days. Succinate dehydrogenase and succinate oxidase activities increased significantly during the hypoxic period of 14 days. No change was observed in cytochrome oxidase activity. Malate dehydrogenase and glutamate dehydrogenase activities increased somewhat, but not significantly. The efficiency of oxidative phosphorylation (the ADP:O ratio) in the isolated mitochondria remained unchanged. The exact mitochondrial protein values showed a 15% decrease as compared with the control group. The concentrations of cytochromes did not change significantly in the hypoxic group. During the short hypoxic period succinate dehydrogenase, succinate oxidase and cytochrome oxidase activities increased as compared with those in the control group.
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PMID:Rat liver mitochondrial enzyme activities in hypoxia. 17 Jul 95

Oxidoreductases were studied histochemically in 162 cases of neuroectodermal tumors. In order of decreasing activity in the cytoplasma these enzymes could be arranged as follows: NADH diaphorase, lactate dehydrogenase, NADPH diaphorase, glutamate dehydrogenase, glucose-6-phosphate dehydrogenase, isocitrate dehydrogenase, succinate dehydrogenase, malate dehydrogenase. The weak activity of Krebs cycle enzymes and the relatively strong activity of other oxidoreductases, particularly of lactate dehydrogenase, permits to conclude that glycolysis prevails over oxidative processes in neuroectodermal tumor cells. But this should not be interpreted as a decrease of the Krebs cycle enzymes in astrocytoma and oligodendroglioma cells as compared with their parent cells because the latter themselves display a weak activity of these enzymes. A real decrease of Krebs cycle enzyme activity was established only for tumors, the parent cells of which are characterized by a strong (in choroid-papillomas) or moderate (in ependymomas) activity of these enzymes. Many neuroectodermal tumors, in particular those of astrocytic origin, demonstrate a certain correlation between the amount of cytoplasm and oxidoreductase activity. This results in enzymatic polymorphism of the tumor tissue. A certain similarity was established of the oxidoreductase activity in tumor cells and in reactive hypertophic astrocytes. This indicates that both tumor cells and reactive astrocytes may in certain conditions utilize similar mechanisms of increased metabolism. The oxidoreductase activity correlates not with the grade of anaplasia but with different directions of anaplasia reflected in different variants of neuroectodermal tumors. The concept "anaplasia" includes not only certain degrees of dedifferentiation of tumor cells but, as it has been shown histochemically, also an increase of metabolic processes in the tumor cell cytoplasma.
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PMID:Histochemistry of oxidoreductases, enzymatic polymorphism and anaplasia of neuroectodermal tumors. 18 68

One hour after a single i.v. dose of 250 mg/kg folic acid, the straight portion of distal tubules in the outer medulla of rat kidneys showed a distinct reduction in succinate dehydrogenase, NADH2-diaphorase, glutamate dehydrogenase, cytochrome oxydase, Na+/K+-ATPase, and acid phosphatase activity. In contrast, the proximal tubules exhibited only a reduction in glutamate dehydrogenase and alkaline phosphatase activity. At this time the straight portion of the distal tubules, whose enzyme activity had changed, showed partly regressive epithelial changes. 24 hours after folic acid administration an even greater reduction in enzyme activity had occurred in the straight portion of distal tubules; these structures also became dilated. The adjacent collecting tubules and the corresponding proximal tubules were also severely dilated, the proximal tubules showing a loss in enzyme acitivities similar to those observed in the distal tubules. 48 hours after folic acid administration the changes largely resembled those observed after 24 hours, but were more pronounced. At this time a tubular regeneration was observed. 72 hours after folic administration extensive normalization of the histological and histochemical changes had occured. It is postulated that a disturbance of the hairpin counter-current mechanism occurs as a result of a direct, concentration-dependent effect of folic acid on the enzymes of the energy supplying metabolism. A dilation in the region of the loop of Henle and the collecting tubules occurs subsequently.
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PMID:Enzyme histochemistry of rat folic acid nephropathy. 19 86

The activities of five mitochondrial enzymes tested in liver from patients with Reye's syndrome were measured. Citrate synthase, glutamic dehydrogenase, succinic dehydrogenase, pyruvate carboxylase, and pyruvate dehydrogenase were all outside of the range shown by control samples and well below them in activity. The activity of two extramitochondrial enzymes, glucose-6-phosphatase, which is a microsomal enzyme, and fructose-1,6-diphosphatase, which is a soluble enzyme, were in the normal range in samples from Reye's syndrome patients. In both muscle and brain the activities of the mitochondrial enzyme, citrate synthase, glutamic dehydrogenase, and succinic dehydrogenase were all within the control range. Pyruvate dehydrogenase was found to be normal in muscle from these patients.
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PMID:Reye's syndrome: preservation of mitochondrial enzymes in brain and muscle compared with liver. 21 43

A crude mitochondrial fraction (M) derived from manually disrupted cerebellar tissue and enriched in choline acetyltransferase (ChAT) activity was fractionated by centrifugation in discontinuous and continuous sucrose gradients. Further purification of 'cholinergic' synaptosomes was achieved (relative specific activity (RSA) of ChAT greater than 3), but the overlap with other synaptosomal populations was still considerable. Hand-homogenized cerebella processed through the full fractionation procedure described here and in previous papers yielded preparations enriched in certain neuronal structures and a fraction in which 'heavy' free mitochondria was concentrated. To characterize these preparations the activities of two transmitter enzymes (CHAT and glutamate decarboxylase, GAD) and 6 mitochondrial enzymes (succinate dehydrogenase (SDH), glutamate dehydrogenase (GDH), monoamine oxidase, citrate synthase, fumarase and GABA-aminotransferase) were determined. The distribution of the transmitter enzymes was clearly different in the preparations containing various neuronal structures. The GAD:ChAT RSA ratio was 2.4 for the glomerulus particles, 1.3 for the molecular layer fragments, 0.6 for the myelinated axon segments, and 0.2 for the 'cholinergic' synaptosomes. The mitochondrial enzyme profile of the preparations comprising mainly neuronal structures differed markedly from that of the 'free' mitochondrial fraction. Notably the latter was greatly enriched in GDH (RSA 5.6), whereas the SDH:GDH RSA ratio was relatively high in the former preparations. Nevertheless there were notable differences in the enzyme profile of the fractions of predominantly neuronal origin indicating that the enzyme composition of mitochondria of neuronal processes is not uniform.
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PMID:Subcellular fractionation of rat cerebellum: separation of synaptosomal populations and heterogeneity of mitochondria. 21 84

The authors have studied the enzymhistochemical and ultrastructural pictures of tenocytes of adult human tendons. High succinate dehydrogenase, cytochrome oxidase, TPN-diaphorase, lactate dehydrogenase and glucose-6-phosphate dehydrogenase activity were found, as indicated both oxidativ, anaerobic and pentose-phosphate shung activity. Phosphorylase and glutamate dehydrogenase activity was medial, lipase and alcaline phosphatase activity was slight. In tenocytes well developed rough endoplasmic reticulum and GOLGI apparatus, large amount of free ribosomes were found.
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PMID:Histochemical and ultrastructural study of adult human tendon. 23 84

Use of the gel film technique in microphotometric determinations of enzyme activity is described. The microscope photometer is computer-controlled. It is programmed to deal with repetitive measurements at up to 12 selected positions within a tissue section and to evaluate recorded reaction rates statistically. Films of polyacrylamide gel with entrapped glucose-6-phosphate dehydrogenase are used as a model to demonstrate the correlation between local enzyme activity and the microphotometrically determined reaction rate. Enzyme activities at different positions in the same tissue section are determined and compared. Activity profiles of five enzymes (glutamate dehydrogenase, lactate dehydrogenase, malate dehydrogenase, succinate dehydrogenase, NAD-dependent tetrazolium reductase) in the liver are presented and show non-uniform intra-acinar distribution patterns. These results are interpreted in the light of the metabolic zonation of the hepatic acinus. Further applications of the method are discussed.
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PMID:Microphotometric determination of enzyme activities in cryostat sections by the gel film technique. 26 70


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