Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:P06889 (Mol)
 630,302 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Several cases of ADP-ribosylation of endogenous proteins in procaryotes have been discovered and investigated. The most thoroughly studied example is the reversible ADP-ribosylation of the dinitrogenase reductase from the photosynthetic bacterium Rhodospirillum rubrum and related bacteria. A dinitrogenase reductase ADP-ribosyltransferase (DRAT) and a dinitrogenase reductase ADP-ribose glycohydrolase (DRAG) from R. rubrum have been isolated and characterized. The genes for these proteins have been isolated and sequences and show little similarity to the ADP-ribosylating toxins. Other targets for endogenous ADP-ribosylation by procaryotes include glutamine synthetase in R. rubrum and Rhizobium meliloti and undefined proteins in Streptomyces griseus and Pseudomonas maltophila.
Mol Cell Biochem 1994 Sep
PMID:Reversible ADP-ribosylation as a mechanism of enzyme regulation in procaryotes. 789 54

During reperfusion of ischemic brain tissue, the production of reactive oxygen species initiates several modifications of the astroglial functional and ultrastructural integrity. During 24 h after ischemic treatment, modification of cellular superoxide free radical scavenging systems have been observed in primary culture of rat astroglial cell. Mitochondrial Mn superoxide dismutase activity (Mn-SOD) gradually decreases, whereas that of the cytosolic Cu,Zn form of the enzyme remains unaffected. We observed in parallel a significant decrease of glutamine synthetase (GS), an astrocyte specifically located enzyme. Addition of almitrine (dialylamine-4',6'-triazinyl 2')-1-(bis-parafluoro-benzydryl)-4-piperazine or dibucaine (a phospholipase A2 inhibitor) antagonizes the decrease of Mn-SOD activity, but does not affect modification of GS activity. Combined effects are observed by simultaneous addition of both drugs. Our data demonstrate that almitrine may increase the synthesis of some mitochondrial proteins, like Mn-SOD, and provide support for further study on the therapeutic potential of almitrine in ischemic astroglial cell injury.
Mol Chem Neuropathol 1993 Oct
PMID:Almitrine prevents some hypoxia-induced metabolic injury in rat astrocytes. 790 67

Changes in the level of glutamine synthetase (GS), an enzyme mainly located in astrocytes, were investigated in rat brain after deprivation of paradoxical sleep (PSD) and during recovery. An immunotitration method was used to evaluate the relative level of GS in brain tissue. At the end of a 24 h PSD, a significant increase in GS protein was observed both in the frontoparietal cortex (CX) and in the locus coeruleus area (LC). Four hours later during recovery, the level of GS protein returned to normal level in the CX but fell below control levels in the LC. In contrast, in the CX, the level of glial fibrillary acidic protein, an astroglial marker, did not change after PSD or during recovery. GS mRNA was quantified in the entire cortex by northern blot hybridization using of an oligonucleotidic GS-cDNA probe. We observed an increase in the GS mRNA level in the cortex of PSD rats of the same magnitude as the increase in GS protein. Both GS mRNA and GS protein tended to return to control values 4 h later during recovery. These results are discussed with particular attention to stress effects and possible physiological mechanisms regarding the regulation of amino acid levels by neurotransmitters during prolonged waking or neuronal excitation.
Brain Res Mol Brain Res 1994 Mar
PMID:Glutamine synthetase modulation in the brain of rats subjected to deprivation of paradoxical sleep. 791 99

A protector protein from Saccharomyces cerevisiae prevented the inactivation of enzyme and oxidative damage to protein and DNA caused by a thiol/Fe3+/O2 metal-catalyzed oxidation (MCO) system but not when thiol was replaced by ascorbate. In the presence of a reduced thiol such as dithiothreitol and reduced glutathione, however, the protector protein prevented inactivation of E. coli glutamine synthetase against a MCO system comprised of ascorbate and Fe3+. The protector protein also inhibited the fragmentation of protein, incorporation of carbonyl groups into protein, strand breaks in pBluescript plasmid DNA, and the formation of 8-hydroxydeoxyguanosine in calf thymus DNA when induced by either the thiol/Fe3+ system or the ascorbate/Fe3+ system supplemented with dithiothreitol. These results suggest that antioxidant activity of protector protein against a MCO system requires thiol as a reducing equivalent to restore its catalytic activity.
Biochem Mol Biol Int 1994 Mar
PMID:Inhibition of metal-catalyzed oxidation systems by a yeast protector protein in the presence of thiol. 791 63

The objective was to determine the effects of persistent obesity on amino acid enzymes in white (WAT) and brown (BAT) adipose tissues. Dietary obesity was induced by feeding a cafeteria diet ad libitum for 3 months, then it was removed and the obese animals received the same diet as controls for 5 months. Dietary-induced obesity was persistent as obese rats showed a stable, higher body weight than controls (26%). Key enzymes of alpha-amino nitrogen metabolism were studied and results showed reduced activities in obese rats: glutamine synthetase (45%), AMP deaminase (52%), alanine aminotransferase (66%) and glutamate dehydrogenase (68%) in BAT, whereas WAT of obese animals only showed lower aspartate aminotransferase activity (47%) with respect to the controls. We can conclude that these adaptations in amino acid metabolism were exclusively dependent on the obese status as they were observed in an obesity model in which obese rats eat the same diet as controls.
Biochem Mol Biol Int 1994 Apr
PMID:Brown and white adipose tissue adaptive enzymatic changes on amino acid metabolism in persistent dietary-obese rats. 791 90

Tissue-specific isozymes of glutamine synthetase are present in elasmobranchs. A larger isozyme occurs in tissues in which the enzyme is localized in mitochondria (liver, kidney) whereas a smaller form occurs in tissues in which it is cytosolic (brain, spleen, etc.). The nucleotide sequence of spiny dogfish shark (Squalus acanthias) liver glutamine synthetase mRNA, derived from its cDNA, shows there are two in-frame initiation codons (AUG) at the N-terminus which will account for the size differences between the two isozymes. Initiation at the up-stream and down-stream sites would yield peptides of 45,406 and 41,869 mol. wts. representing the precursor of the mitochondrial isozyme and the cytosolic isozyme, respectively. The additional N-terminal 29 amino acids present in the mitochondrial isozyme precursor contains two putative cleavage sites based on the Arg-X-(Phe,Ile,Leu) motif. The predicted two-step processing would remove 14 of the 29 N-terminal amino acids. These 14 amino acids can be predicted to form a very strong amphipathic mitochondrial targeting signal. Their removal would yield a mature peptide of 43,680 mol. wt. The calculated mol. wts. based on the derived amino acid sequence are therefore in good agreement with previous estimates of an approximately 1.5-2-kDa difference between the M(r)s of the mitochondrial and cytosolic isozymes. A model for the evolution of the mitochondrial targeting of glutamine synthetase in vertebrates is proposed.
J Mol Evol 1994 Jul
PMID:Genetic basis for tissue isozymes of glutamine synthetase in elasmobranchs. 791 34

Gene expression of two astroglial markers, glial fibrillary acidic protein (GFAP) and glutamine synthetase (GS), was investigated in cerebellum and brainstem from scrapie-affected sheep. The GFAP and GFAP-mRNA concentrations were increased in the two cerebral regions studied in the scrapie-affected animals as compared to the controls. The good correlation between the increase in GFAP and GFAP-mRNA concentrations found in scrapie-affected sheep indicates a significant de novo synthesis of GFAP in this pathology. In contrast to these results, in scrapie no significant differences in GS-mRNA content appeared in either brain area from scrapie-affected sheep as compared to the controls. This fact could suggest some specificity of GFAP expression changes in this pathology. The overexpression of GFAP gene could be related to a possible interaction between GFAP and scrapie infectious agent in astrocytes. The relative increase in the GFAP and its encoding message in affected animals was higher in the cerebellum than in the brainstem, which would suggest regional comparative differences in the effect here described.
Mol Chem Neuropathol 1994 May
PMID:Expression of glial fibrillary acidic protein and glutamine synthetase genes in the natural scrapie of sheep. 791 68

PII protein, which carries metabolic signals regulating the transcription and activity of glutamine synthetase in nitrogen assimilation in Escherichia coli, has been crystallized in space group P2(1) with a = 47.8 A, b = 62.9 A, c = 52.8 A and beta = 100.3 degrees and space group P2(1)2(1)2(1) with a = 52.2 A. b = 64.9 A and c = 100.1 A. Both the monoclinic crystals, which diffract beyond 3.0 A, and the orthorhombic crystals, which diffract beyond 2.5 A, probably have three molecules of 12,400 Da each in the crystallographic asymmetric unit.
J Mol Biol 1994 Nov 04
PMID:Preliminary X-ray diffraction analysis of crystals of the PII protein from Escherichia coli. 796 97

Glucocorticoids are important in neuronal development, regulation of the hypothalamic-pituitary-adrenal axis, adaptive behavior, and neuronal survival. Glia have receptors for glucocorticoid hormones and thus represent targets for hormone action in the brain. To identify mRNAs that are regulated by corticosterone in primary type 1 rat astrocytes, we have utilized ultra-high resolution giant two-dimensional gel electrophoresis of in vitro translated proteins. Our results reveal 12 in vitro translation products likely representing 10 mRNA species that are regulated by corticosterone. Eleven products are significantly increased and one decreased, most within 3 h of hormone treatment. Inclusion of cycloheximide does not prevent these changes, suggesting that they represent alterations in transcription; however, other mechanisms, such as changes in mRNA stability, cannot be excluded. Two corticosterone-regulated proteins were identified as glucocortin and glutamine synthetase. These two proteins are glucocorticoid-regulated in a variety of cell types, whereas the others appear to be astrocyte-specific. Future identification of these hormone-responsive mRNAs and proteins will help elucidate the molecular basis for glucocorticoid action in the CNS.
Brain Res Mol Brain Res 1994 Mar
PMID:Corticosterone-responsive mRNAs in primary rat astrocytes. 801 94

Mutational analysis of the genetic determinants mediating NH(4+)-nitrogen regulating effects on NH(4+)-transport activity, heterocyst differentiation, nitrogenase activity and heterocyst pattern formation was carried out in Nostoc muscorum. Evidence suggested the operation of three separate genetic determinants in such nitrogen control; one mediating NH(4+)-repression control on both heterocyst formation and NH(4+)-transport activity, a second (Nif-R) mediating NH(4+)-repression control on nitrogenase synthesis/activity and a third (Pat-R) essential for intercalary heterocyst formation/distribution. Ammonia itself functioned as repressor signal of heterocyst formation and nitrogenase synthesis/activity and the glutamine synthetase enzyme played no role in the repression/derepression control of heterocyst development and functional nitrogenase formation.
Biochem Mol Biol Int 1994 Feb
PMID:Mutational analysis of the NH4+-nitrogen controls that regulate ammonium transport activity, heterocyst differentiation, nitrogenase activity and the heterocyst-spacing pattern in the cyanobacterium Nostoc muscorum. 801 41


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