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)

Suspensions of enzymatically prepared hepatocytes from starved rats were separated according to their buoyant density at 12 degrees C in linear, isosmotic gradients of metrizamide, centrofuged at low speed for a relatively short time. The recovery of cell protein was 86%. Hepatocytes of high viability formed a single band around 1.10 g/cm3 and were recovered as four density populations (P1-P4) form low to high density, respectively. The content of protein was significantly lower in population P1, while the content of neutral fat or the averaged cell size was similar in the various populations. The specific activity of alanine aminotransferase increased in the order P1-P4. The distribution of this enzyme within the intact liver acinus obtained by others indicate that a partial separation of periportal and perivenous hepatocytes had occurred. The activity patterns of lactate dehydrogenase, glutamate dehydrogenase, isocitrate dehydrogenase (NADP+) and pyruvate kinase, also with known intra acinar distributions, supported this conclusion. The hepatocytes showed signs of shrinkage after separation, but since they retained a normal ultrastructure, most enzyme activities and viability, the present technique was regarded superior to previous procedures of hepatocyte separation by density. The degree of separation was calculated from an equation (see Appendix), and the periportal/perivenous ratio for parameters measured in density populations can be obtained. The specific activity of phosphofructokinase, alcohol dehydrogenase and aldehyde dehydrogenase showed no differences between populations. However, the ratio high-Km/low-Km aldehyde dehydrogenase increased in the order P4-P1.
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PMID:Partial separation and biochemical characteristics of periportal and perivenous hepatocytes from rat liver. 702 82

Activities of 14 enzymes were determined in psoas muscle, smooth muscle, diaphragm, heart, brain, liver, kidney, spleen, pancreas, salivary glands, zygomatic gland, intestinal mucosa, subcellular fractions, and plasma of the dog. In pups, plasma activity of most enzymes was high, except iditol dehydrogenase (ID), glutamate dehydrogenase (GLD), alanine aminotransferase (ALT), aspartate aminotransferase (AST), and D-fructose-1,6-diphosphate aldolase (ALS). Alkaline phosphatase (ALP), ALS, cholinesterase (CHS), creatine kinase (CK), alpha-hydroxybutyrate dehydrogenase (HBD), lactate dehydrogenase (LD), and malate dehydrogenase (MD) decreased significantly (P less than 0.01) with increasing age, but in dogs greater than 7 months, all enzymes except CK, HBD, and ALT revealed reasonably constant plasma values. Enzymes ALT, GLD, CHS, and ID are specific for liver, CK and ALS for muscle, HBD to some degree for myocardium, and alpha-amylase for pancreas. The ALP and gamma-glutamyltransferase were located in microsomes, GLD in mitochondria, MD and AST in mitochondria and cytoplasm, and isocitric dehydrogenase, LD, and the other enzymes only in cytoplasm.
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PMID:Enzyme activities in the dog: tissue analyses, plasma values, and intracellular distribution. 703 2

The chain oxidation of glyceraldehyde-3-phosphate dehydrogenase.NADH by perhydroxyl radicals and propagated by molecular oxygen was studied by the xanthine-xanthine oxidase system, 60Co gamma-ray, and pulse radiolysis. The chain length, amount of NADH oxidized per HO2 generated, increases with increasing acidity of the medium and reaches a value of 73 at pH 5.0. The rate constant for the oxidation of the glyceraldehyde-3-phosphate dehydrogenase.NADH complex by HO2 was estimated to be 2 X 10(7) M-1 S-1 at ambient temperatures (23-24 degrees C). Rate studies as a function of pH indicate that O2- is unreactive toward the glyceraldehyde-3-phosphate dehydrogenase.NADH complex. Other dehydrogenases (malate dehydrogenase, glutamate dehydrogenase, and isocitric dehydrogenase) studied showed no catalytic activity in the oxidation of NADH by HO2/O2-.
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PMID:Glyceraldehyde-3-phosphate dehydrogenase-catalyzed chain oxidation of reduced nicotinamide adenine dinucleotide by perhydroxyl radicals. 718 97

Four bile acid profiles, bilirubin, alkaline phosphatase, alanine aminotransferase, glutamate dehydrogenase, and isocitrate dehydrogenase were measured in rats in which normal bile flow had been disturbed either by administration of alpha-naphthylisothiocyanate or by surgical ligation of the bile duct. The most sensitive index to the early onset of cholestasis was an increase in total cholate. This increase was measurable before morphological changes could clearly be identified.
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PMID:Bile acid assays as an index of cholestasis. 723 63

The activities of 13 liver and 6 brain enzymes were studied in 7-12 week old CD2F1 male mice that had been fed ad libitum and standardized either to 12 hours of light (0600-1800) alternating with 12 hours of darkness (1800-0600) (LD12:12); or to a reversed light-dark cycle (darkness 0600-1800; light 1800-0600) (DL12:12). Three separate studies were performed on two different days; in each experiment, subgroups of 14 animals were sacrificed at 3-hour intervals. Livers were assayed for: isocitrate dehydrogenase, glutamate dehydrogenase, lactate dehydrogenase, alcohol dehydrogenase, glutathione reductase, glyoxylate reductase, L-alanine aminotransferase, glutamate oxalacetate transaminase, pyruvate decarboxylase, fructose-1-phosphate aldolase, fructose diphosphate aldolase, fructose 1,6-diphosphatase, and fatty acid synthetase. Brains were assayed for phosphoglucose isomerase, adenosine triphosphatase, creatine phosphokinase, pyruvate kinase, adenylate kinase, and malate dehydrogenase. All 19 enzymes demonstrated a prominent circadian rhythm in at least one experiment. Moreover, each rhythmic variable showed a statistically significant fit to a 24-hour cosine (sine) curve by the method of least squares. In general, peak activities of the liver enzymes analyzed were associated with the beginning of the dark cycle and initiation of the animal's activity, while the group of brain enzymes had peak activities which occurred at the beginning of the animals' rest span and were near the beginning of the light cycle. The phasing of each of the rhythms could be reversed within a two-week span after reversing the environmental light-dark cycle 180 degrees.
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PMID:Circadian organization of thirteen liver and six brain enzymes of the mouse. 731 49

The activities of nine enzymes in liver specimens obtained from four children who had died from Reye's syndrome were compared to the corresponding activities of a control group of four children who had died from unrelated causes. At the 95% significance level, the alterations could be classified into three groups. Five activities [lactate dehydrogenase, alanine aminotransferase, glucose 6-phosphatase, cytochrome oxidase, and malate dehydrogenase (mitochondrial plus cytosolic)] showed no change. Three enzymes [glutamate dehydrogenase, isocitrate dehydrogenase (NADP), and monoamine oxidase] were decreased. One activity (glucose 6-phosphate dehydrogenase) was increased. The malate dehydrogenase isozymes were resolved by electrophoresis, and the two bands were stained and measured. The ratio of cytosolic:mitochondrial enzyme was significantly greater in Reye's syndrome than in the control group. These results lend further support to the view that in Reye's syndrome the impairment of hepatic function is largely confined to the mitochondria. The lowered activity of monoamine oxidase means that the abnormalities extend to the outer mitochondrial membrane. Imbalances of the cytosolic:mitochondrial enzyme activities were evaluated in needle biopsy specimens from four other children under conditions where neurologic abnormalities were less severe. Two patients had elevated ratios of both glutamate:lactate dehydrogenase and cytosolic:mitochondrial malate dehydrogenase activities, and a third had only an abnormal malate dehydrogenase ratio. In contrast to these Reye's syndrome patients, a fourth case admitted with a provisional diagnosis of Reye's syndrome showed no abnormality in either ratio in stage IV coma.
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PMID:Comparison of cytosolic and mitochondrial hepatic enzyme alterations in Reye's syndrome. 745 35

Defects in cytochrome oxidase (CO; complex 4) have recently been demonstrated in blood platelets and in brain tissue from patients with Alzheimer's disease (AD) with possible etiological implications. Because of pathogenetic similarities with AD, we have measured the activities of several mitochondrially localised enzymes in the blood platelets of individuals afflicted with trisomy-21 (Down's syndrome). The activities of monoamine oxidase, cytochrome oxidase, isocitrate dehydrogenase, and glutamate dehydrogenase were assayed in washed platelets from sixty caucasian, male and female control individuals (ages 18-60) and ten, young Down's Syndrome patients (ages 9-21). Significant reductions in the activities of monoamine oxidase, cytochrome oxidase, and isocitrate dehydrogenase were found. In all cases the average activities in Down's syndrome individuals were approximately two-thirds those of controls (DS/Controls = 0.68, 0.67, 0.64 respectively). The activity of the fourth enzyme studied, glutamate dehydrogenase, was found to be similar to controls. Results suggest that these reductions are a consequence of a generalised mitochondrial disturbance which may lie behind some pathogenetic aspect(s) of the disease.
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PMID:Mitochondrial enzyme deficiencies in Down's syndrome. 774 61

The effects of urea, cations (K+,NH4,Na+,Cs+,Li+), and trimethylamines on the maximal activities and kinetic properties of pyruvate kinase (PK) and phosphofructokinase (PFK) from skeletal muscle were analyzed in two anuran amphibians, an estivating species, the spadefoot toad Scaphiopus couchii, and a semi-aquatic species, the leopard frog Rana pipiens. Urea, which accumulates naturally to levels of 200-300 mM during estivation in toads, had only minor effects on the Vmax, kinetic constants and pH curves of PK from either species and no effects on PFK Vmax or kinetic constants. Trimethylamine oxide neither affected enzyme activity directly or changed enzyme response to urea. By contrast, high KCl (200 mM) lowered the Vmax of toad PFK and of PK from both species and altered the Km values for both substrates of frog PFK. Other cations were even more inhibitory; for example, the Vmax of PK from either species was reduced by more than 80% by the addition of 200 mM NH4Cl, NaCl, CsCi, or LiCl. High KCl also significantly changed the Km values for substrates of toad lactate dehydrogenase and strongly reduced the Vmax of glutamate dehydrogenase and NAD-dependent isocitrate dehydrogenase in both species whereas 300 mM urea had relatively little effect on these enzymes. The perturbing effect of urea on enzymes and the counteracting effect of trimethylamines that has been reported for elasmobranch fishes (that maintain high concentrations of both solutes naturally) does not appear to apply to amphibian enzymes.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Urea and salt effects on enzymes from estivating and non-estivating amphibians. 804 69

The present review focuses on enzymes involved in the metabolism of amino acid neurotransmitters and the microphotometric determinations of their activities in various layers of the rat hippocampus. The enzymes are NAD-linked isocitrate dehydrogenase (NAD-ICDH), glutamate dehydrogenase (GDH), and GABA transaminase (GABAT), all of which are localized in mitochondria. GDH seems to be restricted to astrocytes, whereas NAD-ICDH and GABAT are localized in neurons as well as in astrocytes. NAD-ICDH is an important enzyme of the tricarboxylic acid cycle and may deliver alpha-ketoglutarate for the formation of glutamate and GABA, which serve as neurotransmitters in the hippocampus. GDH catalyses the interconversion of alpha-ketoglutarate and glutamate, whereas GABAT is the important GABA-degrading enzyme and requires alpha-ketoglutarate for its activity. While differing in their cellular distribution and activity levels, NAD-ICDH, GDH and GABAT are significantly correlated in their hippocampal distribution. Furthermore, developmental and pharmacohistochemical studies suggest that the distribution and activity of astrocytic GDH is correlated with amino-acidergic neurotransmission in the hippocampus. The data reported give further evidence for a metabolic relationship between neurons and astrocytes in the turnover and metabolism of glutamate and GABA.
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PMID:In situ measurements of enzyme activities in the brain. 810 May 59

To study the interactions between the citrate cycle and amino acid metabolism in zebrafish spinal motoneurons, we composed enzyme histochemical profiles from the activities of NAD-linked isocitrate dehydrogenase (NAD-ICDH), glutamate dehydrogenase (GDH), succinate dehydrogenase (SDH) and glucose 6-phosphate dehydrogenase (G6PDH). The enzyme assays were performed on serially-sectioned motoneuron somata. The motoneurons were identified by retrograde tracing from the trunk muscle and classified, on the basis of their location in the motor column, as those innervating the white, fast glycolytic fibers (WMNs) or those innervating the red and intermediate slow oxidative fibers (RIMNs). We found the following relationships between enzyme activities in WMNs: GDH correlates with G6PDH activity (r = 0.31; p = 0.02) and NAD-ICDH correlates with GDH activity (r = 0.37; p < 0.01); correlations between NAD-ICDH and SDH and between SDH and GDH are not significant. In RIMNs we found correlations between NAD-ICDH and SDH (r = 0.34; p = 0.03), between NAD-ICDH and GDH (r = 0.41; p < 0.01) and between GDH and SDH (r = 0.50; p < 0.01); the correlation between GDH and G6PDH is not significant. The differences in metabolic profiles between WMNs and RIMNs can be explained in the following way: in WMNs, alpha-ketoglutarate is drawn off from the citrate cycle and is used in amino acid metabolism whereas in RIMNs the removal of alpha-ketoglutarate from the cycle is balanced by formation of alpha-ketoglutarate. The data suggest that the functional role of the citrate cycle differs in the two motoneuron populations: in RIMNs energy generation predominates but in WMNs a role in biosyntheses seems most important.
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PMID:Metabolic profiles of white and red-intermediate spinal motoneurons in the zebrafish. 813 85


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