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)

Response characteristics are presented for a dual-enzyme fiber-optic biosensor for glutamate. An enzyme layer composed of glutamate dehydrogenase (GDH) and glutamate-pyruvate transaminase (GPT) is used to produce reduced nicotinamide adenine dinucleotide (NADH) at the tip of a fiber-optic probe. NADH luminescence is monitored through this probe and the measured fluorescence intensity is related to the concentration of glutamate. GDH catalyzes the formation of NADH, and GPT drives the GDH reaction by removing a reaction product and regenerating glutamate. Optimal response is obtained in a pH 7.4 Tris-HCl buffer maintained at 25 degrees C in the presence of 4 mM NAD+ and 10 mM L-alanine. The temperature profile reveals a strong negative temperature effect which is attributed to the temperature dependency of NADH luminescence. Under optimal conditions, the sensor sensitivity is 0.127 nA/microM over the 1-10 microM concentration range, the detection limit is 0.13 microM, and response times range from 4 to 8 min. The sensor response is stable for 12 days when stored at 4 degrees C. Selectivity for glutamate is excellent over most of the common amino acids as well as ascorbic acid, uric acid, taurine, and GABA. Only slight responses were observed for glutamine and lysine. The effect of ammonia on the glutamate response was found to be minimal at total ammonia nitrogen concentrations as high as 200 microM.
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PMID:Dual-enzyme fiber-optic biosensor for glutamate based on reduced nicotinamide adenine dinucleotide luminescence. 135 Apr 33

The zonal distribution of enzyme activities was measured by quantitative cytochemistry in cryosections of liver from three normal children and five infants with idiopathic hepatitis of infancy. Optimal conditions for cytochemical reactions were first validated in rat liver and subsequently used in human livers to quantify zonal activities of acid phosphatase (AP), succinate dehydrogenase (SDH), glutamate dehydrogenase (GDH), glucose-6-phosphatase (G6P) and NADPH-dehydrogenase (ND). In normal rat and human livers, activities were greater for SDH and G6P in periportal and for GDH and ND in perivenular hepatocytes, while AP was evenly distributed along the sinusoids. In five infants with idiopathic hepatitis of infancy (IHI), a similar trend of distribution was observed for the two mitochondrial (SDH and GDH) and the two microsomal (G6P and ND) enzymes, although the distribution gradient was less pronounced than, in normal livers. AP showed a mildly greater periportal than perivenular activity. This preliminary study shows that a similar metabolic zonation exists for these enzymes in human livers as is observed in rats.
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PMID:The application of quantitative cytochemistry to study the acinar distribution of enzymatic activities in human liver biopsy sections. 254 21

Succinivibrio dextrinosolvens C18 was found to possess glutamine synthetase (GS), urease, glutamate dehydrogenase, and several other nitrogen assimilation enzymes. When grown in continuous culture under ammonia limitation, both GS and urease activities were high and glutamate dehydrogenase activity was low, but the opposite activity pattern was observed for growth in the presence of ample ammonia. The addition of high-level (15 mM) ammonium chloride to ammonia-limited cultures resulted in a rapid loss of GS activity as measured by either the gamma-glutamyl transferase or forward assay method with cells or extracts. No similar activity losses occurred for urease, glutamate dehydrogenase, or pyruvate kinase. The GS activity loss was not prevented by the addition of chloramphenicol and rifampin. The GS activity could be recovered by washing or incubating cells in buffer or by the addition of snake venom phosphodiesterase to cell extracts. Manganese inhibited the GS activity (forward assay) of untreated cells but stimulated the GS activity in ammonia-treated cells. Alanine, glycine, and possibly serine were inhibitory to GS activity. Optimal pH values for GS activity were 7.3 and 7.4 for the forward and gamma-glutamyl transferase assays, respectively. The glutamate dehydrogenase activity was NADPH linked and optimal in the presence of KCl. The data are consistent with an adenylylation-deadenylylation control mechanism for GS activity in S. dextrinosolvens, and the GS pathway is a major route for ammonia assimilation under low environmental ammonia levels. The rapid regulation of the ATP-requiring GS activity may be of ecological importance to this strictly anaerobic ruminal bacterium.
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PMID:Glutamine synthetase activity in the ruminal bacterium Succinivibrio dextrinosolvens. 286 38

Activity of L-amino acid oxidases was studied using several procedures. Optimal concentrations of L-lysine-alpha-oxidase, suitable for each procedure, were established involving highly purified preparations of the enzyme from Trichoderma sp. Estimation of the enzymatic activity carried out by means of calculation of the reduced cofactor accumulated led to two-fold exceeding of the results. The most sensitive procedure was based on evaluation of ammonium content in the reaction catalyzed by glutamate dehydrogenase and the procedure where peroxidase and o-dianizidine were used.
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PMID:[Determination of L-amino acid oxidase activity]. 288 70

Buono, F. (Syracuse University, Syracuse, N.Y.), R. Testa, and D. G. Lundgren. Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids. J. Bacteriol. 91:2291-2299. 1966.-Growth and sporulation were studied in Bacillus cereus by use of an active culture technique and a synthetic medium. A high level of glutamic acid (70 mm) was required for optimal growth and glucose oxidation followed by sporulation even though relatively little glutamic acid was consumed (14 mm). Optimal growth occurred with a combination of 14 mm glutamic acid and 56 mm (NH(4))(2)SO(4), aspartic acid, or alanine. Ornithine or arginine at 70 mm could replace glutamic acid in the synthetic medium without affecting the normal growth cycle. Glutamic acid was not replaced by any other amino acid, by (NH(4))(2)SO(4), or by a combination of either alpha-ketoglutarate or pyruvate plus (NH(4))(2)SO(4). Enzyme assays of cell-free extracts prepared from cells harvested at different times were used to study the metabolism of glutamic acid. Glutamic-oxaloacetic and glutamic-pyruvate transaminases were completely activated (or derepressed) during early stages of sporulation (period of 6 to 8 hr). Alanine dehydrogenase responded in a similar manner, but the levels of this enzyme were much higher throughout the culture cycle. Neither glutamic dehydrogenase nor alpha-ketoglutarate dehydrogenase was detected. Sporulation in a replacement salts medium was studied with cells harvested at different times from the synthetic medium. Cultures 2 to 6 hr old were unable to sporulate in the replacement salts medium unless glutamic acid (7.0 mm) was present. By the 6th hr, cells were in the early stages of sporulation, showing spore septa development. Cultures 8 hr old sporulated in the replacement salts medium. Other metabolic intermediates able to replace glutamic acid in the replacement salts medium were alanine, aspartic acid, and glutamine at equimolar concentrations. Also, ammonium ions in combination with pyruvic, oxaloacetic, alpha-ketoglutaric, or fumaric acid replaced glutamic acid. The likely role of these metabolites is discussed.
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PMID:Physiology of growth and sporulation in Bacillus cereus. I. Effect of glutamic and other amino acids. 495 15

The stability of various marmoset (Callithrix jacchus) plasma constituents was investigated after storage at room temperature, 4 degrees C, and -20 degrees C. The method of sequential analysis ensured that the between-run bias of the methods of analysis used was drastically reduced, and the definitions of stability were linked to the imprecision of these methods. Optimal conditions for storage for as long as 48 h depended on the analyte being measured. Room temperature was optimal for cholinesterase and acetylcholinesterase; 4 degrees C for protein, albumin, alanine aminotransferase, isocitrate dehydrogenase, sorbitol dehydrogenase, lactate dehydrogenase, and glutamate dehydrogenase; and -20 degrees C for glutathione reductase and alkaline phosphatase. For aspartate amino-transferase and gamma-glutamyltransferase, either 4 degrees C or -20 degrees C would be suitable. Reasons are advanced for some conflicting reports in the published work, and we emphasize the need to investigate each analyte and species separately.
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PMID:Stabilities of some constituents of marmoset (Callithrix jacchus) plasma under various conditions of storage. 641 8

There is now increasing evidence that surface-associated enzymes, previously considered to be involved in intermediary metabolism or virulence, play a role in physiological reactions such as signal transduction, transport systems, and metabolic processes. Herein we report the molecular aspects of two such enzymes, the cysteine proteinase gingivain and NAD-dependent glutamate dehydrogenase of Porphyromonas gingivalis. The gdh gene comprises an open reading frame of 1,335 base pairs that encodes a 49,000-M(r) protein of 445 amino acids. The gdh gene showed high homology (78.3%) with that of Clostridium symbiosum. Optimal codons accounted for 35.9% of the total codon usage, indicating high expression of this enzyme. These data are currently being used to carry out targeted mutagenesis, which was established here for gingivain. Conditions for targeted mutagenesis within the histidine domain of the catalytic site of gingivain using Tn 4351 was successfully achieved. Consequently, the catalytic functions, such as gingivain's capacity to hydrolyze the synthetic substrate alpha-benzoyl-arginine-4-nitroanilide, were disrupted.
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PMID:Molecular analysis of surface-associated enzymes of Porphyromonas gingivalis. 754 41

Two methods are proposed for the determination of regional concentrations of glutamate in the rat brain as well as in human serum. Glutamate oxidase was immobilized on non-porous glass beads and glutamate dehydrogenase was immobilized on glass derivatives. These supports were employed for the construction of Single Bead String Reactors and Packed Bed Reactors, respectively, which in turn were linked to Flow Injection Analysis systems with either photometric or fluorometric detection. Analytical working curves are linear in the range 1-200 mumol/l for packed bed reactors and 10-500 mmol/l for single bead string reactors. The samples were pretreated depending on their origin and the applied measuring system. Optimal dilution factors were established for the two techniques. Optimal dilution ratios were established and the influence of several added substances was investigated. Recovery and method comparison studies including high performance liquid chromatography verified the accuracy of the proposed methods. Results from within-day and between-day measurements gave relative standard deviations of 4.7 and 5.9% for serum samples and 2.5 and 4.0% for brain samples, respectively.
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PMID:Flow injection determination of glutamate in human serum and rat brain samples with immobilized glutamate oxidase and glutamate dehydrogenase reactors. 786 14

Alanine aminotransferase (AlaAT) was purified from cell extracts of the hyperthermophilic archaeon Pyrococcus furiosus by multistep chromatography. The enzyme has an apparent molecular mass of 93.5 kDa, as estimated by gel filtration, and consists of two identical subunits of 46 kDa, as deduced by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and the gene sequence. The AlaAT displayed a broader substrate specificity than AlaATs from eukaryal sources and exhibited significant activity with alanine, glutamate, and aspartate with either 2-oxoglutarate or pyruvate as the amino acceptor. Optimal activity was found in the pH range of 6. 5 to 7.8 and at a temperature of over 95 degrees C. The N-terminal amino acid sequence of the purified AlaAT was determined and enabled the identification of the gene encoding AlaAT (aat) in the P. furiosus genome database. The gene was expressed in Escherichia coli, and the recombinant enzyme was purified. The pH and temperature dependence, molecular mass, and kinetic parameters of the recombinant were indistinguishable from those of the native enzyme from P. furiosus. The k(cat)/K(m) values for alanine and pyruvate formation were 41 and 33 s(-1) mM(-1), respectively, suggesting that the enzyme is not biased toward either the formation of pyruvate, or alanine. Northern analysis identified a single 1.2-kb transcript for the aat gene. In addition, both the aat and gdh (encoding the glutamate dehydrogenase) transcripts appear to be coregulated at the transcriptional level, because the expression of both genes was induced when the cells were grown on pyruvate. The coordinated control found for the aat and gdh genes is in good agreement with these enzymes acting in a concerted manner to form an electron sink in P. furiosus.
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PMID:Purification and characterization of the alanine aminotransferase from the hyperthermophilic Archaeon pyrococcus furiosus and its role in alanine production. 1076 59

A new obligately methylotrophic bacterium (strain MTT) with the ribulose monophosphate pathway of carbon assimilation is described. The isolate, utilizing only methanol, is an aerobic, Gram-negative, asporogenous, non-motile short rod multiplying by binary fission. Its cellular fatty acids profile consists primarily of straight-chain saturated C16:0 and unsaturated C16:l acids. The major ubiquinone is Q-8. The dominant phospholipids are phosphatidylethanolamine and phosphatidylglycerol. Diphosphatidylglycerol (cardiolipin) is absent. Optimal growth conditions are 25-29 degree C, pH 6.5 - 7.5, 0.5% CH3OH and 0.05% NaCl. Strain MTT lacks alpha-ketoglutarate dehydrogenase, the glyoxylate shunt enzymes, and glutamate dehydrogenase. Ammonium is assimilated by the operation of the glutamate cycle enzymes: glutamine synthetase and glutamate synthase. An exopolysaccharide consisting of rhamnose, glucose and galactose is formed under nitrogen limitation. The G + C content of the DNA is 54.0 mol%. Based on 16S rDNA sequence analysis and DNA-DNA relatedness (29-34%) with type strains of the genus Methylophilus, the novel isolate was classified as a new species of this genus and named Methylophilus quaylei MTT (VKM B-2338T, DSMZ, etc.).
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PMID:Methylophilus quaylei sp. nov., a new aerobic obligately methylotrophic bacterium. 1599 2


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