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)

We have partially characterized the biochemical parameters of glutamine synthetase from Klebsiella pneumoniae and have shown that the differential affinity of adenylylated and unadenylylated glutamine synthetase for adenosine diphosphate provides a convenient means of determining the adenylylation state. Using this assay procedure, we examined the relationship between the adenylylation state and the expression of other genes involved in nitrogen assimilation. We observed no correlation between the adenylylation state and the expression of histidase, glutamine synthetase, glutamate synthase, glutamate dehydrogenase, and urease in aerobic cultures.
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PMID:Relation between the adenylylation state of glutamine synthetase and the expression of other genes involved in nitrogen metabolism. 3 15

The final products of the arginine catabolism that can be utilized as a nitrogen source in Neurospora crassa are ammonium, glutamic acid, and glutamine. The effect of these compounds on arginase induction by arginine was studied. In wild-type strain 74-A, induction by arginine was almost completely repressed by glutamic acid plus ammonium, whereas ammonium or glutamic acid alone had only moderate effects. Arginine products of catabolism also repressed arginase induction. A mutant, ure-1, which lacks urease activity, hyperinduced its arginase with arginine as a nitrogen source. The addition of either ammonium or glutamine produced effects similar to those in the wild-type strain. The effect of ammonium on arginase induction is mediated through its conversion into glutamine. This was demonstrated in mutant am-1, which lacks L-glutamate dehydrogenase activity. In this mutant, the effect of glutamic acid was reduced, and, with ammonium, it was completely lost. The addition of glutamine or glutamic acid plus ammonium to this strain decreased by threefold the induction of arginase by arginine. Proline, a final product of arginine catabolism, competitively inhibited arginase activity. This effect and the repression of arginase by glutamine are examples of negative modulation of the first enzyme in a catabolic pathway by its final products.
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PMID:Nitrogen regulation of arginase in Neurospora crassa. 14 62

A microencapsulated multienzyme system containing urease, glutamate dehydrogenase and glucose dehydrogenase has been used to convert urea and ammonia into an amino acid. The effect of two different glucose dehydrogenases was studied in detail. High-specific-activity glucose dehydrogenase requires minimal cofactor and glucose and can greatly facilitate the further development of this approach for possible clinical applications.
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PMID:Effects of glucose dehydrogenase in converting urea and ammonia into amino acid using artificial cells. 43 22

We describe a fixed-time-interval, kinetic inhibition method, with use of a competitive inhibitor (l) of the urease/glutamate dehydrogenase reaction to increase the "apparent" Michaelis constant by a factor of (1 + [l]lKl). This allows greater flexibility in selecting an appropriate sample dilution for kinetic determinations of urea in serum (i.e., [S]lKm ratio). Nine compounds were screened as potential inhibitors for this study. Adding 5 mmol of hydroxyurea per liter increases the "apparent" Michaelis constant for the coupled enzyme reaction by 10-fold. We used a sample dilution of 21-fold vs. dilutions of 141- to 350-fold for previously reported kinetic methods. Mean analytical recovery with this method was 100.2%. Reaction rate vs. urea concentration was linear, and complete recovery extended to 30 mmol of urea per liter. Of 22 potential interferents, only fluoride (250 mmol/L) and bilirubin (1 mmol/L, or 580 mg/L) caused greater than 5% interference. We discuss precision and effects of specimen dilution, and compare results for 100 specimens with those by a manual Berthelot-indophenol method, a manual diacetyl monoxime method, and a diacetyl monoxime method adapted to continuous-flow analysis.
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PMID:Chemical inhibition used in a kinetic urease/glutamate dehydrogenase method for urea in serum. 47 21

Seventeen strains of the new species Bacillus azotoformans were isolated by enrichment culture in peptone broth inoculated with pasteurized soil and then incubated under N2O at 32 degrees C. The bacterium is a Gram-negative rod, motile with peritrichous flagella, which produces oval spores without exosporia in swollen sporangia. However, the cells have thick walls, mesosomes, and persistent septa characteristic of Gram-positive bacteria. The bacterium lacks fermentative activity, does not attack carbohydrates, has complex growth requirements, and will grow anaerobically only if one of the following electron acceptors is present: NO3-, NO2-, N2O, S4O6--, or fumarate. Nitrate, nitrite, and nitrous oxide are denitrified with the production of N2. The microorganism is mesophilic, gives a positive oxidase reaction, synthesizes a type c cytochrome, and does not hydrolyse gelatin, starch, or "Tween 80." Poly-beta-hydroxybutyric acid is snythesized when the bacterium is grown in a medium containing DL-3-hydroxybutyrate. The following enzymes are present: nitrate reductase A, respiratory nitrite reductase, tetrathionate and fumarate reductases, and L-glutamate dehydrogenase. The following enzymes are absent: thiosulfate reductase, urease, lecithinase, arginine dihydrolase, phenylalanine deaminase, and catalase. For the 17 strains, the mean value of the G = C percent of the DNA is 39.8 +/- 1.2. All the strains are highly similar.
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PMID:[Morphological, physiological and taxonomic studies of Bacillus azotoformans]. 65 12

The kinetic determination of urea based on the urea/glutamate dehydrogenase method was adapted for the LKB Reaction Rate Analyzer System 8600. A ratio of sample to reagent volume of 1:50 ensures linearity up to 33.3 mmol/l with a day to day precision of 5%. Parallel studies with the urease/glutamate dehydrogenase method were performed with the CentrifiChem System and with the manual Berthelot/Salicylate method.
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PMID:[Kinetic determination of urea with the LKB system (author's transl)]. 95 32

A direct enzymatic micromethod (sample volume, 3mul) has been adapted to the centrifugal analyzer (ENI-GEMSAEC) for measurement of urea in plasma and urine. The method is based on urease (urea amidohydrolase, EC3.5.1.5)/glutamate dehydrogenase [l-glutamate:NAD(P)+oxidoreductase (deaminating), EC1.41.3] coupled reactions, and uses a two-point fixed-time (t(1)=20s,t(2)=50s)kinetic scheme for monitoring the rate of comsumption of NADH at 340 nm. Sensitivity and precision of the method are excellent,and results compare well with those from a commonly used continuous-flow method.
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PMID:Direct enzymatic determination of urea in plasma and urine with a centrifugal analyzer. 97 5

The described bacterium was isolated by enrichment culture in peptone broth inoculated with garden soil, pasteurized and then put to incubate under N2O at 32 degrees. It is a Gram-negative rod, motile with peritrichous flagella, and producing oval spores without exosporium in swollen sporangia. However, cells have the thick walls, mesosomes and persistant septa characteristic of Gram-positive bacteria. It lacks fermentative activity, does not attack carbohydrates, has complex growth requirements, and will grow anaerobically only if one of the following electron acceptors is present: NO3, NO2, N2O, S4O6, and fumarate. Nitrate, nitrite, and nitrous oxide are denitrified with production of N2. The microorganism is mesophilic, gives a positive oxidase reaction, synthesizes a type of c cytochrome, and does not hydrolyse gelatin, starch nor "Tween 80". The following enzymes are present: nitrate reductase A, respiratory nitrite reductase, tetrathionate and fumarate reductases, L-glutamate dehydrogenase, and superoxide dismutase. The following enzymes are absent: thiosulfate reductase, urease, lecithinase, arginine dihydrolase, L-alanine dehydrogenase, phenylalanine desaminase, and catalase. The GC% of its DNA is 39. The bacterium described can be considered to be a new species. We propose the name Bacillus azotoformans n. sp.
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PMID:[A new, sporulating, denitrifying, mesophilic bacterium: Bacillus azotoformans N. SP. (author's transl)]. 102 Aug 72

The adsorption of 8 enzymes to polyaminomethylstyrene was studied. While lactate dehydrogenase, alkaline phosphatase and glucose-6-phosphate dehydrogenase exhibit a relatively low affinity to the carrier, alcohol dehydrogenase, glutamate dehydrogenase and urease were found to form stabile complexes with the polymer that are enzymatically active. Adsorbed urease and beta-hydroxybutyrate dehydrogenase, are still active after several weeks; the other preparations lose their activity soon. It can be shown by the example of yeast alcohol dehydrogenase that the activity loss following adsorption is caused possibly by a process of reorientation of already bound enzyme molecules or by the increasing enzyme coverage of the carrier, with the active centres becoming more and more inaccessible for the substrate. During the substrate conversion catalysed by the alcohol dehydrogenase-polyaminomethylstyrene complex, a small amount of the enzyme is again detached from the carrier. The activity rises to a certain extent in the supernatant but drops to zero again. The stability of the adsorbed urease is distinctly increased compared with the dissolved enzyme. For the pH optimum and the KM value there are no differences between the two preparations. Continuous application of polyaminomethylstyrene-bound beta-hydroxybutyrate dehydrogenase and urease, respectively, in a column shows that both preparations have unchanged enzymatic activities even after running times of 5 and 24 days, respectively.
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PMID:[Kinetic properties of enzymes in particular of yeast alcohol dehydrogenase following their adsorption on polyaminomethylstyrene]. 102 29

An enzymatic, fluorometric method is described for determination of serum urea on silicone-rubber pads. In this method, the reagents are lyophilized on the surface of the pads, NADH on one side and a mixture of urease, glutamate dehydrogenase, and alpha-ketoglutarate on the other. The rate of disappearance of NADH fluorescence at 460nm (excitation wavelength, 340 nm) is monitored and related to serum urea concentration. The calibration curve is linear to 250 mg of urea per liter. The method affords a rapid, simple, and inexpensive means for urea assay, the results of which correlate well with automatic diacetyl monoxime method (correlation coefficient, 0.998).
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PMID:Enzymatic determination of serum urea on the surface of silicone-rubber pads. 111 80


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