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:1.4.1.4 (glutamate dehydrogenase)
4,358 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Unlike other lactic acid bacteria, Lactococcus lactis subsp. lactis NCDO 2118 was able to grow in a medium lacking glutamate and the amino acids of the glutamate family. Growth in such a medium proceeded after a lag phase of about 2 days and with a reduced growth rate (0.11 h-1) compared to that in the reference medium containing glutamate (0.16 h-1). The enzymatic studies showed that a phosphoenolpyruvate carboxylase activity was present, while the malic enzyme and the enzymes of the glyoxylic shunt were not detected. As in most anaerobic bacteria, no alpha-ketoglutarate dehydrogenase activity could be detected, and the citric acid cycle was restricted to a reductive pathway leading to succinate formation and an oxidative branch enabling the synthesis of alpha-ketoglutarate. The metabolic bottleneck responsible for the limited growth rate was located in this latter pathway. As regards the synthesis of glutamate from alpha-ketoglutarate, no glutamate dehydrogenase was detected. While the glutamate synthase-glutamine synthetase system was detected at a low level, high transaminase activity was measured. The conversion of alpha-ketoglutarate to glutamate by the transaminase, the reverse of the normal physiological direction, operated with different amino acids as nitrogen donor. All of the enzymes assayed were shown to be constitutive.
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PMID:Glutamate Biosynthesis in Lactococcus lactis subsp. lactis NCDO 2118 964 19

The maximum rate (Vmax) of some mitochondrial enzymatic activities related to the energy transduction (citrate synthase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, cytochrome oxidase) and amino acid metabolism (glutamate dehydrogenase, glutamate-pyruvate-transaminase, glutamate-oxaloacetate-transaminase) was evaluated in non-synaptic (free) and intra-synaptic mitochondria from rat brain cerebral cortex. Three types of mitochondria were isolated from rats subjected to i.p. treatment with L-acetylcarnitine at two different doses (30 and 60 mg.kg-1, 28 days, 5 days/week). In control (vehicle-treated) animals, enzyme activities are differently expressed in non-synaptic mitochondria respect to intra-synaptic "light" and "heavy" ones. In fact, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, malate dehydrogenase, glutamate-pyruvate-transaminase and glutamate-oxaloacetate-transaminase are lower, while citrate synthase, cytochrome oxidase and glutamate dehydrogenase are higher in intra-synaptic mitochondria than in non-synaptic ones. This confirms that in various types of brain mitochondria a different metabolic machinery exists, due to their location in vivo. Treatment with L-acetylcarnitine decreased citrate synthase and glutamate dehydrogenase activities, while increased cytochrome oxidase and alpha-ketoglutarate dehydrogenase activities only in intra-synaptic mitochondria. Therefore in vivo administration of L-acetylcarnitine mainly affects some specific enzyme activities, suggesting a specific molecular trigger mode of action and only of the intra-synaptic mitochondria, suggesting a specific subcellular trigger site of action.
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PMID:Action of L-acetylcarnitine on different cerebral mitochondrial populations from cerebral cortex. 982 Nov 51

The effect of various metabolic inhibitors on the rate of oxygen consumption by procyclic culture forms of Trypanosoma congolense utilizing proline as substrate was investigated. Cyanide inhibited the rate of oxygen consumption by 81.0 +/- 6.7%, malonate inhibited the rate by 51.6 +/- 1.6% and Antimycin A by 73.1 +/- 5.9%. A combination of cyanide and malonate inhibited the rate of oxygen consumption by 84.9 +/- 6.7% while a combination of antimycin A and malonate inhibited the rate by 81.6 +/- 7.6%. Rotenone had no effect on the rate of respiration except when the intact cells were first permeabilized by digitonin after which rotenone decreased the rate of respiration by 20-30%. Salicylhydroxamate (SHAM) did not have any effect on the rate of oxygen consumption. Enzymes involved in the catabolism of proline with high activities were: proline dehydrogenase, alpha-ketoglutarate dehydrogenase, succinate dehydrogenase, fumarase, NADP-linked malic enzyme, alanine aminotransferase and malate dehydrogenase. Activities of 1-pyrroline-5 carboxylate dehydrogenase, glutamate dehydrogenase, aspartate aminotransferase and NAD-linked malic enzyme were detectable but lower. The end products of proline catabolism were alanine and glutamate. Unlike the case in Trypanosoma brucei brucei aspartate was not detected. Possible pathways of proline catabolism in procyclic culture forms of T. congolense and of electron transfer are proposed.
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PMID:Catabolism of proline by procyclic culture forms of Trypanosoma congolense. 1042 13

Exposure to hyperoxia (500-600 torr) or low pH (4.5) for 72 h or NaHCO(3) infusion for 48 h were used to create chronic respiratory (RA) or metabolic acidosis (MA) or metabolic alkalosis in freshwater rainbow trout. During alkalosis, urine pH increased, and [titratable acidity (TA) - HCO(-)(3)] and net H(+) excretion became negative (net base excretion) with unchanged NH(+)(4) efflux. During RA, urine pH did not change, but net H(+) excretion increased as a result of a modest rise in NH(+)(4) and substantial elevation in [TA - HCO(-)(3)] efflux accompanied by a large increase in inorganic phosphate excretion. However, during MA, urine pH fell, and net H(+) excretion was 3.3-fold greater than during RA, reflecting a similar increase in [TA - HCO(-)(3)] and a smaller elevation in phosphate but a sevenfold greater increase in NH(+)(4) efflux. In urine samples of the same pH, [TA - HCO(-)(3)] was greater during RA (reflecting phosphate secretion), and [NH(+)(4)] was greater during MA (reflecting renal ammoniagenesis). Renal activities of potential ammoniagenic enzymes (phosphate-dependent glutaminase, glutamate dehydrogenase, alpha-ketoglutarate dehydrogenase, alanine aminotransferase, phosphoenolpyruvate carboxykinase) and plasma levels of cortisol, phosphate, ammonia, and most amino acids (including glutamine and alanine) increased during MA but not during RA, when only alanine aminotransferase increased. The differential responses to RA vs. MA parallel those in mammals; in fish they may be keyed to activation of phosphate secretion by RA and cortisol mobilization by MA.
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PMID:Renal responses of trout to chronic respiratory and metabolic acidoses and metabolic alkalosis. 1044 55

Many halogenated foreign compounds are detoxified by conversion to the corresponding cysteine S-conjugate, which is N-acetylated and excreted. However, several halogenated cysteine S-conjugates [e.g. S-(1,1,2,2-tetrafluoroethy)-L-cysteine (TFEC)] are converted to mitochondrial toxicants by cysteine S-conjugate beta-lyases. In the present work, we showed that TFEC appreciably inactivated highly purified alpha-ketoglutarate dehydrogenase complex (KGDHC) in the presence of a cysteine S-conjugate beta-lyase. Incubation of PC12 cells (which contain endogenous cysteine S-conjugate beta-lyase activity) with TFEC led to a concentration- and time-dependent loss of endogenous KGDHC activity. A 24-hr exposure to 1 mM TFEC decreased KGDHC activity in the cells by 90%. Although treatment with TFEC did not inhibit intrinsic pyruvate dehydrogenase complex (PDHC) activity, it inhibited dichloroacetate/Mg2+-mediated activation/dephosphorylation of PDHC in the PC12 cells by 90%. To determine the selectivity of enzymes targeted by TFEC, several cytosolic and mitochondrial enzymes involved in energy metabolism [malate dehydrogenase, glyceraldehyde 3-phosphate dehydrogenase, glutamate dehydrogenase, lactate dehydrogenase, cytosolic and mitochondrial aspartate aminotransferases (AspAT)] were also assayed in the PC12 cells exposed to 1 mM TFEC for 24 hr. Of these enzymes, only mitochondrial AspAT, a key enzyme of the malate-aspartate shuttle, was inhibited. The present results demonstrate a selective vulnerability of mitochondrial enzymes to toxic cysteine S-conjugates. The data indicate that TFEC may be a useful cellular/mitochondrial toxicant for elucidating the consequences of the diminished mitochondrial function that accompanies numerous neurodegenerative diseases.
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PMID:Inhibition of select mitochondrial enzymes in PC12 cells exposed to S-(1,1,2,2-tetrafluoroethyl)-L-cysteine. 1053 46

Recent data from our laboratory have shown a regionally specific increase in lipid peroxidation in postmortem progressive supranuclear palsy (PSP) brain. To extend this finding, we measured activities of mitochondrial enzymes as well as tissue malondialdehyde (MDA) levels in postmortem superior frontal cortex (Brodmann's area 9; SFC) from 14 pathologically confirmed cases of PSP and 13 age-matched control brains. Significant decreases (-39%) in alpha-ketoglutarate dehydrogenase complex/glutamate dehydrogenase ratio and significant increases (+36%) in tissue MDA levels were observed in the SFC in PSP; no differences in complex I or complex IV activities were detected. Together, these results suggest that mitochondrial dysfunction and lipid peroxidation may underlie the frontal metabolic and functional deficits observed in PSP.
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PMID:Frontal lobe dysfunction in progressive supranuclear palsy: evidence for oxidative stress and mitochondrial impairment. 1064 41

Aluminum is a neurotoxic agent for animals and humans that has been implicated as an etiological factor in several neurodegenerative diseases and as a destabilizer of cell membranes. Due to its high reactivity, Al3+ is able to interfere with several biological functions, including enzymatic activities in key metabolic pathways. In this paper we report that, among the enzymes that constitute the Krebs cycle, only two are activated by aluminum: alpha-ketoglutarate dehydrogenase and succinate dehydrogenase. In contrast, aconitase, shows decreased activity in the presence of the metal ion. Al3+ also inhibits glutamate dehydrogenase, an allosteric enzyme that is closely linked to the Krebs cycle. A possible correlation between aluminum, the Krebs cycle and aging processes is discussed.
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PMID:Effects of aluminum on activity of krebs cycle enzymes and glutamate dehydrogenase in rat brain homogenate. 1080 5

The activity level and some physico-chemical properties of enzymes of the tricarboxylic acid cycle (TCA cycle) and the associated enzymes isocitrate lyase and glutamate dehydrogenase of cyanobacterium Spirulina platensis grown under illumination of 5000 lk in batch conditions, have been studied. High activities of most of the studied enzymes except for alpha-ketoglutarate dehydrogenase (alpha-KGDH) and succinate dehydrogenase have been estimated. In some cases the activities were by an order higher than that of similar enzymes in other cyanobacteria. This reflects the microorganism ability to synthesize intensively organic substances and first of all protein. Absence of alpha-KGDH activity proves that TCA cycle of spirulina has a limited value for energy generation and mainly performs the biosynthetic function.
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PMID:[Activity of tricarboxylic acid cycle enzymes in cyanobacteria Spirulina platensis]. 1130 83

Five synthetic, conformationally restricted alpha-ketoglutarate analogues were tested as substrates of a variety of dehydrogenases and aminotransferases. The compounds were found not to be detectable substrates of glutamate dehydrogenase, L-leucine dehydrogenase, L-phenylalanine dehydrogenase, lactate dehydrogenase, malate dehydrogenase, glutamine transaminase K, aspartate aminotransferase, alanine aminotransferase, and alpha-ketoglutarate dehydrogenase complex. However, two thermostable aminotransferases were identified that catalyze transamination between several L-amino acids (e.g., phenylalanine, glutamate) and the alpha-ketoglutarate analogues of interest. Transamination between L-glutamate (or L-phenylalanine) and the alpha-ketoglutarate analogues was found to be 0.13 to 1.08 micromol/h/mg at 45 degrees C. The products resulting from transamination between L-phenylalanine and the alpha-ketoglutarate analogues were separated by reverse-phase HPLC, and the newly formed amino acid analogues were analyzed by LC-MS in an ion selective mode. In each case, the ions obtained were consistent with the expected product and a representative example is provided. The possibility existed that although the alpha-ketoglutarate analogues are not substrates of the dehydrogenases and most of the aminotransferases investigated, they might be good inhibitors. Weak inhibition of aminotransferases and glutamate dehydrogenase was found with some of the alpha-ketoglutarate analogues. The newly available thermostable aminotransferases may have general utility in the synthesis of bulky L-amino acids from the corresponding alpha-keto acids.
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PMID:Analysis of conformationally restricted alpha-ketoglutarate analogues as substrates of dehydrogenases and aminotransferases. 1170 Sep 82

Six young men performed five 1-min bicycle exercise bouts to exhaustion. Muscle lactate increased to congruent with 114 mmol x kg(-1) dwt and pH decreased to congruent with 6.6. Mitochondria were prepared from a needle biopsy sample taken from m. vastus lateralis immediately after the last exercise bout. No significant effect of exhaustion on the proton permeability and amount of cytochromes c and aa3 in isolated mitochondria was detected. The activities of the following enzymes and systems were not altered either: citrate synthase, succinate dehydrogenase, cytochrome oxidase, succinate + glutamate respiration, malate + glutamate respiration, the respiratory chain, and the reactions involved in ATP synthesis. Thus, the mitochondria did not appear globally altered upon exhaustion. However, the following NAD-linked activities were significantly lowered: pyruvate dehydrogenase, alpha-ketoglutarate dehydrogenase, glutamate dehydrogenase and fatty acid beta-oxidation. The activities of alpha-glycerophosphate dehydrogenase and exo-NADH oxidase, enzymes that might catalyze the oxidation of sarcoplasmic NADH, were increased. These changes may be due to the action of reactive oxygen species, protons and Ca2+. Transient opening of the permeability transition pore may also be involved. Some effects may have been reversed during isolation of the mitochondria and the changes in mitochondrial function in situ upon exhaustion may have been more extensive than observed.
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PMID:The effect of high-intensity exhaustive exercise studied in isolated mitochondria from human skeletal muscle. 1171 42


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