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)

The developmental pattern of several key enzymes in brain of pups born to mothers receiving high levels of iodide (1.1 mg daily intake) during pregnancy and lactation were followed up to the weaning period. We found that in the initial states of postnatal development, glutamic dehydrogenase increased above control levels, whereas succinic dehydrogenase decreased. At late stages, we observed differences in phosphofructokinase and malic enzyme activities which were all increased at 30 days. There was no change in hexokinase. Animal weight did not vary with respect to controls and we only obtained discrete increases (not statistically different) in serum thyroxine values, which led us to assume that the enzymatic modifications might be a consequence of either a very mild hormonal alteration or to the direct effect of iodide.
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PMID:Effect of chronic ingestion of iodide during pregnancy and lactation on rat pup brain enzymes. 294 85

Twenty-one enzymes of different metabolic systems were measured in the rabbit fast-twitch tibialis anterior (TA) muscle after electrical stimulation (10 Hz, 24 h/day) for 1 day to 10 wk. Nine analytical methods are either new, (3-oxoacid CoA-transferase, branched-chain-amino-acid aminotransferase, carnitine acetyltransferase, thiolase), improved (glutamate dehydrogenase, glycogen synthase, adenylic acid deaminase), or specially adapted (hexokinase, phosphoglucomutase). The activities (based on protein) of 12 mitochondrial or partly mitochondrial enzymes were lower in control TA than in control (slow) soleus (30-84% of soleus level). After 2 wk, 11 of these had surpassed the control soleus level. Maximal increases (3- to 14-fold) occurred after 2-5 wk, and thereafter six of the enzymes declined, whereas the other five maintained or increased their levels. Five glycolytic and two high-energy phosphate transfer enzymes, originally much higher in control TA than in control soleus, decreased gradually to levels at 8-10 wk only 27-123% higher than in soleus. Noncollagen protein concentration dropped 46%, explained largely by a sixfold increase in extracellular (chloride) space and a modest increase in collagen. The data constitute strong evidence for coordinate regulation of (mainly cytosolic) enzymes of glycolysis, glycogenolysis, gluconeogenesis, and high-energy phosphate transfer. Changes in the (mainly mitochondrial) enzymes of oxidative metabolism were more divergent, partly because of a hitherto undescribed secondary phase in the metabolic response. This phase may reflect a lower energy consumption in muscles adapted to continuous activity.
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PMID:Chronic stimulation of mammalian muscle: changes in enzymes of six metabolic pathways. 294 40

We recently described a preferential reduction of the secretory response to nutrient secretagogues (glucose; leucine plus glutamine) in islets maintained in culture after in vitro exposure to streptozotocin (SZ). The present study is an attempt to further clarify the biochemical mechanisms behind this defective insulin response. Mouse pancreatic islets were collagenase isolated and, after 4-5 days in culture, exposed during 30 min at 37 C to 1.8 mM SZ or vehicle alone (controls). The islets were subsequently cultured for 7 days in medium RPMI 1640 plus 10% calf serum, before the enzymatic and metabolic studies were performed. The activities of the glycolytic enzymes, hexokinase, glucokinase, and glyceraldehyde 3-phosphate dehydrogenase, were similar in the control and SZ-exposed islets. The relative amount of cytosolic and mitochondria-bound hexokinase was also unaffected by SZ. However, there was a 30-40% decrease in the activity of NAD+- and NADP+-dependent glutamate dehydrogenase and glutamate-aspartate transaminase in the SZ-treated islets. This coincided with a 40% decrease in L-[U-14C]glutamine oxidation in the SZ-treated islets. The D-glucose catabolism was further examined in the presence of D-[5-3H] and D-[6-14C] glucose. There was no difference between control and SZ islets in terms of glucose utilization at either 1.7 or 16.7 mM glucose. The oxidation of D-[6-14C]glucose was nevertheless decreased by more than 50% in SZ islets incubated at 16.7 mM (but not 1.7 mM) glucose. Altogether, these converging observations suggest a perturbation of distal regulatory processes, apparently at the mitochondrial level, in the D-glucose and L-glutamine catabolism of SZ-exposed islets. Whether this reflects a primary action of SZ on the islet mitochondria, or an inhibitory effect of SZ on the synthesis of mitochondrial enzymes, as a result of nuclear DNA damage, remains to be elucidated.
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PMID:Defective catabolism of D-glucose and L-glutamine in mouse pancreatic islets maintained in culture after streptozotocin exposure. 296 23

A major difference between the metabolism of Leishmania species amastigotes and cultured promastigotes was found in the area of CO2 fixation and phosphoenolpyruvate metabolism. Malate dehydrogenase (EC 1.1.1.37) and phosphoenolpyruvate carboxykinase (EC 4.1.1.49) were at much higher activities in amastigotes than promastigotes of both L. m. mexicana and L. donovani, whereas the reverse was true of pyruvate kinase (EC 2.7.1.40). Pyruvate carboxylase (EC 6.4.1.1) and malic enzyme (carboxylating) (EC 1.1.1.40) could not be detected in L. m. mexicana amastigotes. Promastigotes of L. m. mexicana had a high NAD-linked glutamate dehydrogenase activity in comparison to amastigotes, whereas NADP-linked glutamate dehydrogenase activity was detected only in amastigotes. Leishmania m. mexicana culture promastigotes were killed in vitro by the trivalent antimonial Triostam (LD50, 20 micrograms/ml) and the trivalent arsenical melarsen oxide (LD50, 20 micrograms/ml), but they were unaffected by Pentostam. Neither antimonial drug significantly inhibited leishmanial hexokinase (EC 2.7.1.2), phosphofructokinase (EC 2.7.1.11), pyruvate kinase, malate dehydrogenase or phosphoenolpyruvate carboxykinase, whereas melarsen oxide was a potent inhibitor of all the enzymes tested except phosphoenolpyruvate carboxykinase.
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PMID:Leishmania mexicana: enzyme activities of amastigotes and promastigotes and their inhibition by antimonials and arsenicals. 298 38

Two main groups of quantitative methods are used in the brain to relate enzymatic processes to cellular structures, i.e. the methods of microchemistry and microscopic histochemistry. Microchemistry tries to quantify enzyme activities in very small brain regions by miniaturizing biochemical methods, whereas microscopic histochemistry applies staining procedures to tissue sections, preserving the structural relationship that is present in situ and giving topological information on the distribution of enzymes which is indispensable in structural heterogeneous tissue as is the brain. The present review deals preferentially with microscopic methods and, in particular, with scanning microphotometry (image plane scanning). Using this technique two measuring procedures can be applied for the quantification of enzyme activities, i.e. end-point and kinetic (continuous monitoring) measurements which are described in detail. Methods for the microphotometric demonstration of certain important dehydrogenases (isocitrate dehydrogenases, succinate dehydrogenase, NAD-linked malate dehydrogenase, glutamate dehydrogenase and glycerol 3-phosphate dehydrogenase), of cytochrome c oxidase, hexokinase and acetylcholinesterase are presented. These methods were adapted for giving optimal demonstration of enzyme activities in the rat hippocampus. The examples are given to illustrate the aptitude and possibilities of this technique in the quantification of enzymes in the complex matrix of the brain.
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PMID:Quantitative enzyme histochemistry in the brain. 306 15

The effect of hypoxia and post-hypoxic recovery were studied in gastrocnemius muscle of young-adult and mature beagle dogs. Furthermore, the possible interference of pharmacological treatment with nicergoline was evaluated in these conditions. Muscular glycolytic fuels, intermediates and end-products (glycogen, glucose, glucose 6-phosphate, pyruvate, lactate), Kreb's cycle intermediates (citrate, alpha-ketoglutarate, succinate, malate) and related free amino acids (glutamate, alanine), ammonium ion, energy store and mediators (ATP, ADP, AMP and creatine phosphate), and the energy charge potential were evaluated. Furthermore, in the crude extract and/or mitochondrial fraction of another portion of the same gastrocnemius muscle the maximum rate (Vmax) of some muscular enzymes related to the anaerobic glycolytic pathway (hexokinase, lactate dehydrogenase), the Kreb's cycle (citrate synthase, malate dehydrogenase), the aminoacid pool related to the Krebs' cycle (glutamate dehydrogenase and aspartate aminotransferase), the electron transfer chain (cytochrome oxidase) and NAD+/NADH exchanges (total NADH cytochrome c reductase) was evaluated. Some glycolytic metabolites and Krebs' cycle intermediates were modified by acute hypoxia, while free amino acids and energy mediators remained practically unchanged. The pharmacological treatment maintained the glucose and succinate muscular concentrations within the normal range, during hypoxia. The behaviour of muscular metabolites during hypoxia and/or post-hypoxic recovery is an age-related event. In fact, only in young-adult animals did the altered values return to normal in post-hypoxic recovery. In the present experimental conditions, only minor changes were observed as far as muscular enzyme activities are concerned. In any case, some enzyme activities tested showed different Vmax in young-adult dogs in comparison with mature ones.
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PMID:Effect of hypoxia, aging and pharmacological treatment on muscular metabolites and enzyme activities. 322 9

The activities of certain key enzymes have been measured in the ventral medial and ventral lateral areas of the hypothalamus, which are implicated in feeding behaviour, and compared with enzyme activities in the cortex and brainstem. The enzymes measured are concerned with glucose metabolism [hexokinase (EC 2.7.1.1) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49)], ketone body metabolism [3-hydroxybutyrate dehydrogenase (EC 1.1.1.30)], fatty acid utilisation [carnitine palmitoyl transferase (EC 2.3.1.7)], citric acid cycle activity [pyruvate dehydrogenase (EC 1.2.4.2) and citrate synthase (EC 4.1.3.7)] and neurotransmitter synthesis [glutamate dehydrogenase (EC 1.4.1.3)].
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PMID:Enzyme activities in regions of the hypothalamus. 380 3

Homogenates of insulin-producing tumoral cells catalyzed the phosphorylation of glucose, mannose, and fructose. The kinetics of phosphorylation at increasing glucose concentrations, the inhibitory effect of glucose 6-phosphate, and the comparison of results obtained with distinct hexoses indicated the presence of both low-Km hexokinase-like and high-Km enzymatic activities, the results being grossly comparable to those collected in normal pancreatic islets. Relative to protein content, the glucose-phosphorylating enzymatic activity was higher in tumoral than normal islet cells. The activity of other enzymes was either lower (glutamate dehydrogenase), moderately higher (phosphoglucomutase, lactate dehydrogenase) or considerably greater (ornithine decarboxylase) in tumoral than in normal islet cells. In intact tumoral cells, incubated under increasing glucose concentrations, the oxidation of D-[U-14C]glucose and the output of lactic and pyruvic acids reached a close-to-maximal value at 2.8 mM glucose. The ratios for glucose oxidation/utilization and lactate/pyruvate output were much lower in tumoral than in normal islet cells. Although glucose caused a modest increase in insulin output from the tumoral cells, this effect was saturated at a low glucose concentration (2.8 mM) and less marked than that of other secretagogues (e.g., L-leucine, L-ornithine, or forskolin). Thus, despite a close-to-normal enzymatic equipment for glucose phosphorylation, the tumoral cells displayed severe abnormalities in the metabolism and secretory response to this hexose. These findings point to regulatory mechanisms distal to glucose phosphorylation in the control of glucose metabolism in insulin-producing cells.
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PMID:Glucose metabolism in insulin-producing tumoral cells. 389 13

The metabolic properties of mitochondria from rat cerebral cortex and olfactory bulb were investigated. The pyruvate-supported oxygen uptake rates by olfactory bulb mitochondria were significantly lower than those by cerebrocortical mitochondria. This is consistent with the differences in pyruvate dehydrogenase complex activities between these mitochondrial preparations. Pyruvate dehydrogenase kinase, NAD-linked isocitrate dehydrogenase, and hexokinase activities in olfactory bulb mitochondria were significantly lower than those in cerebrocortical mitochondria. However, NADP-linked isocitrate dehydrogenase, and NAD-linked and NADP-linked glutamate dehydrogenase activities in olfactory bulb mitochondria were significantly higher than those in cerebrocortical mitochondria. The differences between these two mitochondrial preparations in terms of the activities of these energy-metabolizing enzymes reflect the differences detected in the homogenates of these regions.
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PMID:Differences in some of the metabolic properties of mitochondria isolated from cerebral cortex and olfactory bulb of the rat. 404 57

Redistribution of axonal enzymes as a function of time in vitro was studied in an unbranched segment of frog sciatic nerve. Cholinesterase activity moved peripherally at a rate of 99 mm/day and centrally at 19 mm/day. One-quarter of the total nerve content of the enzyme was estimated to be in motion, one-eighth in each direction. Mitochondrial enzymes (hexokinase and glutamic dehydrogenase) moved peripherally at 20-31 mm/day, centrally at 11-20 mm/day. Only 10% of the total content of these mitochondrial enzymes was in motion. No movement of choline acetylase or 6-phosphogluconic dehydrogenase activity was seen even after 4 days in vitro. However, in a 12 day in vivo experiment choline acetylase moved toward the periphery at a rate of 0.34 mm/day. After a day or so in vitro the distal accumulations of cholinesterase and glutamic dehydrogenase decreased, with a concomitant and quantitatively equivalent increase in enzyme activities at the proximal end of the nerve. It is postulated that during incubation a mechanism for reversing the direction of flow develops in the peripheral stump of the nerve. Vinblastine inhibited central and peripheral flow of both cholinesterase and glutamic dehydrogenase. Movement of cholinesterase was not affected by ouabain, thalidomide, or phenobarbital, nor by K(+) excess (110 mM) or absence.
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PMID:Transport of axonal enzymes in surviving segments of frog sciatic nerve. 411 99


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