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)

NADP+-specific glutamate dehydrogenase (EC 1.4.1.4) was purified to homogeneity from the extremely thermophilic, strictly anaerobic, sulfate-reducing archaeon Archaeoglobus fulgidus strain 7324. The native enzyme (263 kDa) is composed of subunits of mol. mass 46 kDa, suggesting a hexameric structure. The temperature optimum for enzyme activity was > 95 degrees C. The enzyme was highly thermostable, having a half-life of 140 min at 100 degrees C. Potassium phosphate, KCl, and NaCl enhanced the thermal stability and increased the rate of activity three- to fourfold. The N-terminal 26-amino-acid sequence showed a high degree of similarity to glutamate dehydrogenases from Pyrococcus spp. and Thermococcus spp.
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PMID:Purification and properties of an extremely thermostable NADP+-specific glutamate dehydrogenase from Archaeoglobus fulgidus. 938 47

NADP-linked glutamate dehydrogenase (NADP+-GluDH, EC 1.4.1.4) has been purified to homogeneity from epimastigotes of Trypanosoma cruzi by an improved procedure, and the amino acid sequences of 11 internal peptides obtained by digestion with trypsin, endopeptidase Lys-C, endopeptidase Arg-C or CNBr have been obtained. Using oligonucleotide primers synthesized according to the amino acid sequence of the N-terminus of the mature enzyme and to the nucleotide sequence of a clone corresponding to the C-terminus, obtained by immunological screening of an expression library, two complete open reading frames (TcGluDH1 and TcGluDH2) were isolated and sequenced. The sequences obtained are most similar to that of the NADP+-GluDH of Escherichia coli (70-72% identity), and less similar (50-56%) to those of lower eukaryotes. Using TcGluDH1 as a probe, evidence for the presence of several genes and developmental regulation of the expression of NADP+-GluDH in different parasite stages was obtained. TcGluDH1 encodes an enzymically active protein, since its expression in E. coli resulted in the production of a GluDH activity with kinetic parameters similar to those of the natural enzyme.
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PMID:The NADP+-linked glutamate dehydrogenase from Trypanosoma cruzi: sequence, genomic organization and expression. 948 Sep 15

The gene of an NADP+-specific glutamate dehydrogenase was cloned from Plasmodium falciparum, the causative agent of tropical malaria. Southern-blot analysis indicates a single-copy gene. The gene encodes a protein with 470 residues which has 50% of all residues identical with those of the glutamate dehydrogenases from other low eukaryotes and eubacteria. In contrast, the sequence identity with the human enzyme is marginal, which underlines the long evolutionary distance between parasite and host. The gene was overexpressed in Escherichia coli. The kinetic properties of the recombinant enzyme are in good agreement with those of the authentic enzyme. The parasite enzyme is inhibited by D-glutamate and glutarate, but not by chloroquine. Like other coenzyme-specific glutamate dehydrogenases, but in contrast to the dual-specific mammalian enzymes, the P. falciparum enzyme is not affected by GTP and ADP. The physical and chemical properties of the protein are in accordance with the cytosol being the major localization. The gene does not encode a cleavable mitochondrial presequence and the Mr of the recombinant protein and the protein isolated from the parasite are indistinguishable on SDS/PAGE. Western-blot analysis of stage-specific parasites shows that glutamate dehydrogenase is present in all intraerythrocytic stages. The signal increased continuously from rings, early trophozoites to late trophozoites and decreased slightly in the segmenter stage. Glutamate dehydrogenase, suggested to be the major source of NADPH in the parasite, is an attractive target molecule for the rational development of new antimalarial drugs.
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PMID:Glutamate dehydrogenase, the marker protein of Plasmodium falciparum--cloning, expression and characterization of the malarial enzyme. 987 51

We describe the separation of an active glutamate dehydrogenase [GDH (NADP+)] enzyme from the plasma of patients with P. falciparum infection using columns of sepharose anti-GDH (NADP+) of Proteus spp. The activity of this enzyme was also detected in P. falciparum culture supernatant. The parasitic origin of this enzyme was suggested by western blot analysis using anti-P. falciparum culture supernatant and anti-whole parasite antibodies. The differential inhibition of the P. falciparum GDH (NADP+) indicates that some epitopes recognised by the antibodies in both preparations may be different. The determination of P. falciparum GDH (NADP+) activity could be developed into a specific technique for the diagnosis of falciparum malaria.
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PMID:Detection of glutamate dehydrogenase enzyme activity in Plasmodium falciparum infection. 1040 63

Chlorophyllide a was coupled with alpha-(3-aminopropyl)-omega-methoxypoly(oxyethylene) (PEG-NH2) to form a PEG-chlorophyllide conjugate through an acid-amide bond. The conjugate catalyzed the reduction of methylviologen in the presence of 2-mercaptoethanol. It also catalyzed the photoreduction of NADP+ or NAD+ in the presence of ascorbate as an electron donor and ferredoxin-NADP+ reductase as the coupling enzyme. Utilizing the reducing power of NADPH generated by PEG-chlorophyllide conjugate under illumination, glutamate was synthesized from 2-oxoglutarate and NH4+ in the presence of glutamate dehydrogenase. PEG-chlorophyllide conjugate was quite stable toward light illumination compared with chlorophyll a. The increase in the molecular weight of PEG in the PEG-chlorophyllide conjugates was accompanied by the enhancement of photostability of the conjugate and also by the increased solubility in the aqueous solution.
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PMID:Glutamate synthesis via photoreduction of NADP+ by photostable chlorophyllide coupled with polyethylene-glycol. 1140 Jan 10

A GDH gene from Halobacterium salinarum has been cloned and sequenced and the publication assigns the sequence to the NADP+-glutamate dehydrogenase of this organism. We have expressed this gene in Escherichia coli and find that it encodes an NAD+-dependent glutamate dehydrogenase without activity towards NADP+. Further, peptide sequence from the two corresponding proteins supports the view that the deposited sequence is indeed that of the NAD+-dependent glutamate dehydrogenase. Sequence from the NAD+-dependent protein matches the published gene sequence, whereas sequence from the NADP+ glutamate dehydrogenase does not.
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PMID:Glutamate dehydrogenase of Halobacterium salinarum: evidence that the gene sequence currently assigned to the NADP+-dependent enzyme is in fact that of the NAD+-dependent glutamate dehydrogenase. 1205 48

Aluminum inactivated glutamate dehydrogenase (GDH) by a pseudo-first-order reaction at micromolar concentrations. A double-reciprocal plot gave a straight line with a k(inact) of 2.7 min(-1) and indicated the presence of a binding step prior to inactivation. The inactivation was strictly pH dependent and a marked increase in sensitivity to aluminum was observed as the pH decreased. At a pH higher than 8.5, no inactivation was observed. The completely inactivated GDH contained 2 mol of aluminum per mole of enzyme subunit monomer. When preincubated with enzyme, several chelators such as citrate, NaF, N-(2-hydroxyethyl) ethylenediaminetriacetic acid or ethylenediaminetriacetic acid efficiently protected the enzyme against the aluminum inactivation. In a related experiment, only citrate and NaF released the aluminum from the completely inactivated aluminum-enzyme complex and fully recovered the enzyme activity. Ferritin, NADP+, or nerve growth factor did not show any effects on the recovery of the aluminum-inactivated GDH activity. The dissociation constant for the aluminum-enzyme complex was calculated to be 5.3 microM. Although aluminum has been known to form a complex with nucleotides, no such effects were observed in the inactivation of GDH by aluminum as determined using GDHs mutated at the ADP-binding site, NAD+-binding site or GTP-binding site. Circular dichroism studies showed that the binding of aluminum to the enzyme induced a decrease in alpha helices and beta sheets and an increase in random coil. Therefore, inactivation of GDH by aluminum is suggested to be due to the conformational change induced by aluminum binding. These results suggest a possibility that aluminum-induced alterations in enzymes of the glutamate system may be one of the causes of aluminum-induced neurotoxicity.
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PMID:Inactivation of human glutamate dehydrogenase by aluminum. 1462 97

Peptostreptococcus asaccharolyticus glutamate dehydrogenase (L-glutamate: NAD+ oxidoreductase (deaminating); EC 1.4.1.2) overexpressed in Escherichia coli has been purified by two new methods. Enzyme made by the first method showed remarkable thermophilicity, with a temperature optimum of 60 degrees C, and also thermostability, which suggested the second, simpler method, incorporating a heat step. This produced 94 mg of homogeneous protein per litre culture medium. The basic kinetic parameters for P. asaccharolyticus glutamate dehydrogenase with all substrates are revealed at pH 7.0. The enzyme is highly specific for NAD+, with values for kcat/Km 405 times greater than for NADP+. In the reverse direction of reaction, the kcat/Km value for NADH is almost 1000-fold greater than for NADPH.
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PMID:Properties of the thermostable glutamate dehydrogenase of the mesophilic anaerobe Peptostreptoccus asaccharolyticus purified by a novel method after over-expression in an Escherichia coli host. 1572 21

In earlier work, two glutamate dehydrogenase (GDH) proteins were purified from a strain of the halophilic archaeon Halobacterium salinarum (NRC-36014). One of these, an NAD+-specific enzyme, was matched to a cloned gene from H. salinarum (GenBank accession number: X63837 S75579) by sequencing peptide fragments. Analysis of enzymatic digests of the NADP+-GDH and database searching have now established that a gene encoding this protein exists in the full genomic sequence of Halobacterium sp. NRC-1 as gdhA1, together with two other distinct gdh genes, gdhA2 and gdhB. From N-terminal sequence, it is clear that the genomic listing incorrectly assigns the start codon for gdhA1 and the corresponding protein is 43 amino acids longer than previously indicated. The three genes could be amplified by PCR either from NRC-1, as expected, or from NRC-36014 (GenBank accession numbers: YA840085-AY840087). A gene encoding the previously purified NAD+-GDH, is absent from the NRC-1 genome but can be successfully amplified from genomic DNA of NRC-36014 (GenBank accession number: AY840088). This establishes that NRC-36014 contains four gdh genes.
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PMID:The discovery of four distinct glutamate dehydrogenase genes in a strain of Halobacterium salinarum. 1578 Sep 99

Tomato seedlings grown on nitric medium and treated with various cadmium concentrations (0 to 50 microM) were used. Results obtained show that cadmium remains predominantly located in the roots, which then seem to play the role of trap-organs. Increasing cadmium concentration in the medium leads particularly to a decrease in NO3- accumulation, together with a decrease in the activity of glutamine synthetase and in the quantity of plastidic isoform ARNm (GS2), and, on the contrary, to an increase of the cytosolic isoform ARNm (GS1). On the other hand, stimulations were observed for NADH-dependent glutamate synthase, NADH-dependent glutamate dehydrogenase, ARNm quantity of this enzyme, ammonium accumulation, and protease activity. In parallel, stimulations were observed for NAD+ and NADP+-dependent malate dehydrogenase and NADP+-dependent isocitrate dehydrogenase. These results were discussed in relation to the hypothesis attributing to the dehydrogenase enzymes (GDH, MDH, ICDH) an important role in the plant defence processes against cadmium-induced stresses.
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PMID:[Implication of glutamate, isocitrate and malate deshydrogenases in nitrogen assimilation in the cadmium-stressed tomato]. 1702 40


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