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)

The influence of the relA1 mutation on the regulation of the ammonia assimilatory enzymes, glutamate dehydrogenase (EC 1.4.1.4), glutamine synthetase (EC 6.3.1.2), and glutamate synthase (EC 1.4.1.3), was examined. When cells grown in rich media (either Luria broth or glucose-ammonia plus casamino acids) were transferred to a glucose-ammonia medium, the relA mutant failed to resume growth and did not have the same increase in any of the assimilatory enzyme activities as the rel+ strain. This effect was particularly dramatic for glutamate dehydrogenase, which increased 6-fold in the rel+ strain. Measurements of the guanosine nucleotide concentrations showed that the rel+ strain had a ppGpp concentration about 9 times that of the relA mutant 5 min after the shift to minimal medium. These results are consistent with those for other biosynthetic enzymes and show that the ammonia assimilatory enzymes require a relA product for their synthesis during shift from rich to minimal media. In addition, we examined the response of these strains to a change in nitrogen source. The relA mutant again failed to resume growth after a shift from glucose-ammonia to glucose-arginine medium. Even though the ppGpp concentration did not increase, the rel+ strain grew and increased glutamine synthetase activities about 2-fold. These changes the absence of increased ppGpp levels suggest that some other relA-mediated function is important during this change in nitrogen source.
Mol Gen Genet 1982
PMID:The regulation of the ammonia assimilatory enzymes in Rel+ and Rel- strains of Salmonella typhimurium. 628 74

The malate dehydrogenase (MDH) electrophoretic mobilities of 128 strains of bacteroides belonging to 17 species, including three subspecies of Bacteroides melaninogenicus and two subspecies of Bacteroides ruminicola, were examined. Amongst the pigmented bacteroides, the migration of this enzyme correlated well with recognized taxa, and only one strain, VPI 9085 was clearly different. Other species such as B. oralis, B. buccalis, B. denticola, B. pentosaceus, B. bivius, B. disiens and B. ruminicola were delineated by the combined use of MDH and glutamate dehydrogenase. Forty-three strains belonging to the 'B. fragilis group' differed from the above species in possessing glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase, and reference strains as well as fresh isolates were assigned to the correct species by the mobility pattern of these two enzymes. Other properties of MDH such as the pH optima for the oxidation of malate or the reduction of oxaloacetate were of limited taxonomic value. However, the alkaline stability of this enzyme at pH 9, 10 and 11 clearly differentiates the saccharolytic from the non-saccharolytic species of pigmented bacteroides with the latter showing highly stable enzymes with a half life greater than 50 min.
J Gen Microbiol 1982 Dec
PMID:Dehydrogenase patterns in the taxonomy of Bacteroides. 718 48

Expression of the Neurospora crassa am (NADP-specific glutamate dehydrogenase) gene is controlled by two upstream enhancer-like elements designated URSam alpha and URSam beta. URSam alpha is localized between - 1.3 and - 1.4 kb with respect to the major transcriptional start site. Deletion of a 90 bp sequence containing this element resulted in the loss of approximately 50% of normal glutamate dehydrogenase expression. Gel mobility shift analysis indicated that a nuclear protein from Neurospora binds in a specific manner to sequences within the 90 bp fragment. We have now used a combination of ion-exchange and affinity chromatography to purify this nuclear protein, which we call Am Alpha Binding protein (AAB). The activity was monitored by gel shift analysis. The protein was purified more than 14,000-fold with a yield of approximately 7%. The purified protein appears as a heteromer on denaturing polyacrylamide gel electrophoresis, with only two strong bands visible in silver-stained preparations. One band has an apparent molecular mass of 40 kDa, the other appears as a doublet with an apparent molecular mass of 30 kDa. DNAse I protection analysis indicated a protected region consisting of 30 bp, which contains a CCAAT pentanucleotide motif. Mutagenesis of the CCAAT motif abolished the binding of AAB to the DNA fragment.
Mol Gen Genet 1995 Nov 27
PMID:Purification of a heteromeric CCAAT binding protein from Neurospora crassa. 750 Sep 55

In Bacillus subtilis, the AhrC protein represses genes encoding enzymes of arginine biosynthesis and activates those mediating its catabolism. To determine how this repressor also functions as an activator, we attempted to clone catabolic genes by searching for insertions of the Tn917-lacZ transposon that express AhrC-dependent, arginine-inducible beta-galactosidase activity. One such isolate was obtained. The region upstream of lacZ was subcloned in Escherichia coli in such a way that it could be replaced in the B. subtilis chromosome after appropriate manipulation. Analysis of exonuclease III-derived deletions located an AhrC-dependent, arginine-inducible promoter to within a ca. 1.9 kb fragment. The sequence revealed: the 3' end of an ORF homologous to gdh genes encoding glutamate dehydrogenase, with highest homology to the homologue from Clostridium difficile; the 5' end of an ORF homologous to a Saccharomyces cerevisiae gene encoding delta 1-pyrroline 5-carboxylate dehydrogenase (P5CDH), an enzyme of arginine catabolism; and just upstream of the latter, a sequence with homology to known AhrC binding sites in the upstream part of the biosynthetic argCJBD-cpa-F cluster. The same region has also been sequenced by others as part of the B. subtilis genome sequencing project, revealing that the P5CDH gene is the first in a cluster termed rocABC. Restriction fragments containing the putative AhrC-binding sequence, but not those lacking it, showed retarded electrophoretic mobility in the presence of purified AhrC. A 277 bp AhrC-binding fragment also showed anomalous mobility in the absence of AhrC, consistent with its being intrinsically bent. DNAse I footprinting localized AhrC binding to bp -16/-22 to +1 (the transcription startpoint). Such a location for an activator binding site, i.e. overlapping the transcription start, is unusual.
Mol Gen Genet 1995 Aug 21
PMID:A binding site for activation by the Bacillus subtilis AhrC protein, a repressor/activator of arginine metabolism. 756 95

We have used gel mobility shift assays to scan 1.7 kb of 5' non-coding sequence of the am (glutamate dehydrogenase) gene of Neurospora crassa for binding by partially fractionated Neurospora proteins. Using genetic analysis this region had been shown to play an important role in the control of glutamate dehydrogenase (GDH) expression. Gel mobility shift analysis identified three regions to which Neurospora proteins bind specifically. Two of these corresponded to the two elements previously defined by genetic analysis (URSam alpha and URSam beta). The third protein binding site appears to be unrelated to am gene expression. Competition experiments showed that the proteins that bind to the URSam alpha and URSam beta elements are different. The URSam alpha element was shown to contain two independent binding sites for the URSam alpha binding protein(s). Both fragments contain a CCAAT motif, suggesting that URSam alpha binding protein(s) may be members of one of the CCAAT-binding protein families. The effect of deletion of either the URSam alpha or URSam beta elements on catabolite induction of am expression was also determined. Both elements appear to act as constitutive enhancers of gene expression.
Mol Gen Genet 1994 Feb
PMID:Sequential gel mobility shift scanning of 5' upstream sequences of the Neurospora crassa am (GDH) gene. 812 95

gdhA1 is a spontaneous mutant of Escherichia coli that causes complete loss of activity of the NADP-specific glutamate dehydrogenase (GDH) encoded by the gdhA gene. The gdhA1 mutational site has been identified by recombinational mapping, polymerase chain reaction (PCR) amplification and DNA sequencing, as an A to G transition at nucleotide 274 of the gdhA coding sequence, resulting in an amino acid change of lysine 92 to glutamic acid. The mutant enzyme forms hybrid hexamers with a wild-type GDH, providing a useful system for analysis of conformational integrity of mutational variants.
Mol Gen Genet 1993 Aug
PMID:The gdhA1 point mutation in Escherichia coli K12 CLR207 alters a key lysine residue of glutamate dehydrogenase. 835 60

Nicotinamide-adenine-dinucleotide-specific glutamate dehydrogenase (NAD-GDH; EC 1.4.1.3) from Bacillus cereus DSM 31 was enriched 260-fold. The molecular mass was determined by gel filtration to be 270 kDa (+/- 25 kDa). The enzyme was highly specific for the coenzyme NAD(H) and catalysed both the formation and the oxidation of glutamate. Apparent Km values of 7.7 mM for glutamate and 0.56 mM for NAD+ during oxidative deamination were measured. Both in crude cell-free extracts and in enriched preparations the enzyme was extremely unstable, especially at low temperatures. The loss of activity in the cold was found to be due to the dissociation of the holoenzyme into catalytically inactive subunits of molecular mass 48 kDa (+/- 5 kDa), indicating that the native enzyme has a hexameric structure. The activity was restored under certain conditions, and no instability of the enzyme in the cold was observed in undisrupted cells.
J Gen Microbiol 1993 Apr
PMID:Properties of the cold-labile NAD(+)-specific glutamate dehydrogenase from Bacillus cereus DSM 31. 851 35

The gene encoding NADP+-dependent glutamate dehydrogenase (gdhA) was isolated from an Agaricus bisporus recombinant phage lambda library. The deduced amino acid sequence would specify a 457-amino acid protein that is highly homologous in sequence to those derived from previously isolated and characterized genes coding for microbial NADP+-GDH. The open reading frame is interrupted by six introns. None of the introns is located at either one of the positions of the two introns conserved in the corresponding open reading frames of the ascomycete fungi Aspergillus nidulans and Neurospora crassa. Northern analysis suggests that the A. bisporus gdhA gene is transcriptionally regulated and that, unlike the case in ascomycetes, transcription of this gene is repressed upon the addition of ammonium to the culture.
Mol Gen Genet 1996 Feb 25
PMID:Nucleotide sequence and expression of the gene encoding NADP+- dependent glutamate dehydrogenase (gdhA) from Agaricus bisporus. 860 49

The gene encoding glutamine synthetase (glnA) was isolated from an Agaricus bisporus H39 recombinant lambda phage library. The deduced A. bisporus glutamine synthetase amino acid sequence contains 354 residues. The amino acid sequence is very similar to that derived from the gene coding for glutamine synthetase of the yeast Saccharomyces cerevisiae. The open reading frame is interrupted by four introns. Northern analysis revealed that transcription of the gene is repressed upon addition of ammonium to the culture but the repression was not as strong as that of the gene encoding NADP+ -dependent glutamate dehydrogenase (gdhA). Enzyme activities are low in the presence of ammonium, glutamine and albumin and do not correlate with the mRNA levels revealed by Northern analysis. This suggests that glutamine synthetase expression in A. bisporus is also post-transcriptionally regulated by the nitrogen source.
Mol Gen Genet 1997 Sep
PMID:Molecular characterization of the glnA gene encoding glutamine synthetase from the edible mushroom Agaricus bisporus. 934 9

The gdhA gene encoding glutamate dehydrogenase (GDH) from the hyperthermophilic archaeon Pyrococcus sp. KOD1 was cloned and sequenced. Phylogenetic analysis was performed on an alignment of 25 GDH sequences including KOD1-GDH, and two protein families were distinguished, as previously reported. KOD1-GDH was classified as new member of the hexameric GDH Family II. The gdhA gene was expressed in Escherichia coli, and recombinant KOD1-GDH was purified. Its enzymatic characteristics were compared with those of the native KOD1-GDH. Both enzymes had a molecular mass of 47,300 Da and were shown to be functional in a hexameric form (284 kDa). The N-terminal amino acid sequences of native KOD1-GDH and the recombinant GDH were VEIDPFEMAV and MVEIDPFEMA, respectively, indicating that native KOD1-GDH does not retain the initial methionine at the N-terminus. The recombinant GDH displayed enzyme characteristics similar to those of the native GDH, except for a lower level of thermostability, with a half-life of 2 h at 100 degrees C, compared to 4 h for the native enzyme purified from KOD1. Kinetic studies suggested that the reaction is biased towards glutamate production. KOD1-GDH utilized both coenzymes NADH and NADPH, as do most eukaryal GDHs.
Mol Gen Genet 1998 Feb
PMID:Sequence analysis of glutamate dehydrogenase (GDH) from the hyperthermophilic archaeon Pyrococcus sp. KOD1 and comparison of the enzymatic characteristics of native and recombinant GDHs. 952 Feb 68


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