Disease relevance of GLUL

• There is homology between the mammalian GS enzymes and glutamine synthetases obtained from plants and cyanobacteria but no obvious homology between the CHO cell GS sequence and that of other ATP hydrolysing enzymes [1].

Psychiatry related information on GLUL

• Beta amyloid peptides (A beta), etiologically associated with Alzheimer's disease (AD), have been shown to inhibit both glutamine synthetase (GS) and creatine phosphokinase (CPK) in vitro [2].

High impact information on GLUL

• The ability of unsaturated fatty acid methyl esters to modify amino acid residues in bovine serum albumin (BSA), glutamine synthetase, and insulin in the presence of a metal-catalyzed oxidation system [ascorbate/Fe(III)/O(2)] depends on the degree of unsaturation of the fatty acid [3].
• These latter results suggest that the mutually exclusive expression of either carbamoyl-phosphate synthetase I or glutamine synthetase may be unique to mammalian liver [4].
• Neither glutamine synthetase nor carbamoyl-phosphate synthetase I and ornithine transcarbamoylase (EC 2.1.3.3) are strictly zoned in liver of the Texas tortoise or of an Argentine tree frog, both of which possess a complete urea cycle but which may also rely on glutamine synthetase for ammonia detoxication [4].
• In mammalian liver, glutamine synthetase is cytosolic and its distribution is restricted to a few hepatocytes around the terminal venules [4].
• The nucleotide sequence for a glutamine synthetase (GS) mRNA from gene-amplified Chinese hamster (CHO) cells was determined from recombinant cDNA clones obtained from both pBR322 and lambda gt10 libraries and by primer extension [1].

Biological context of GLUL

• The bovine glutamine synthase gene (GLUL) maps to 10q33 and a pseudogene (GLULP) to 16q21 [5].
• The cloning and nucleotide sequence of cDNA for an amplified glutamine synthetase gene from the Chinese hamster [1].
• The predicted amino acid sequence, starting from an initiation codon with the preferred sequence surrounding it, indicates that Chinese hamster GS has high homology with published bovine brain GS peptides and enabled an ordering of these peptides [1].
• A bacterial glutamate-aspartate binding protein, as well as the enzymes glutamate dehydrogenase (EC 1.4.1.3), glutamine synthetase (EC 6.3.1.2), and gamma-glutamyl transpeptidase (EC 2.3.2.2), showed little or no cross-reactivity with the anti-GBP antibodies [6].
• We questioned whether methionine sulfoxide would inhibit GS and CPK directly and if this inhibition also involved free radical oxidative stress [2].

Anatomical context of GLUL

• In membranes containing the intact undigested A2AR protein, guanine nucleotides induce a small to insignificant decrease in agonist binding, which is atypical of stimulatory GS-coupled receptors [7].
• Membrane proteins of Mr 240,000, 130,000, and 85,000 (GS-proteins) were rapidly and selectively phosphorylated in particulate fractions of rabbit aortic smooth muscle in the presence of [Mg-32P]ATP and low concentrations of cGMP (Ka = 0.01 microM) or cAMP (Ka = 0.2 microM) [8].
• Effects of adenosine analogues on ADP ribosylation of GS protein in coronary artery [9].

Associations of GLUL with chemical compounds

• Our data, therefore, suggest that, unless proteolysis occurs, the A2AR in all tissues studied is tightly associated with the GS protein and displays minimal guanine nucleotide modulation of agonist binding, which makes the A2AR an atypical stimulatory receptor [7].
• ADP, chloride ion, and metal ion binding to bovine brain glutamine synthetase [10].
• These results indicate that the action of methionine sulfoxide may not be directly due to the oxidation of GS by free radicals [2].
• In this report, we demonstrate that methionine sulfoxide inhibits GS by about 50% and CPK by about 25% at 20 mM concentration [2].
• The glutamine synthetase and the NADP-specific glutamate dehydrogenase activities of Neurospora crassa were lost in a culture without carbon source only when in the presence of air [11].

Enzymatic interactions of GLUL

• Calcineurin (CN) dephosphorylated [32P] phosphotyrosyl glutamine synthetase, a model phosphoprotein substrate containing approximately 1 mol of phosphotyrosine per mol subunit [12].

Other interactions of GLUL

• Use of reversed-phase high-performance liquid chromatography for simultaneous determination of glutamine synthetase and glutamic acid decarboxylase in crude extracts [13].
• In the present study, we found SP-22 to have the ability to scavenge reactive oxygen species, thus protecting radical-sensitive proteins such as tryptophan hydroxylase, glutamine synthetase and hemoglobin from oxidation [14].
• The fractions were analyzed for: light scattering, protein, choline acetyltransferase, L-glutamate decarboxylase, glutamine synthetase, 2',3'-cyclicnucleotide-3'-phosphohydrolase, acetylcholinesterase and succinate dehydrogenase [15].

Analytical, diagnostic and therapeutic context of GLUL

• These cells do not express carbamoyl-phosphate synthetase I. Using immunocytochemistry, we show here that there is little or no zonation of glutamine synthetase in avian liver [4].
• In situ hybridization with a cloned glutamine synthetase cDNA probe showed the distribution of glutamine synthetase mRNA in both mammalian and avian liver to correspond to the distribution of immunoreactive protein [4].
• The membrane-bound and cytosolic forms of G-kinase phosphorylated the Mr 130,000 GS-protein with the same specificity as determined by two-dimensional peptide mapping [8].
• Immunodiffusion of antiretinal GS antibodies gave a single line of precipitation with both crude retinal and brain enzymes as well as purified enzyme preparations [16].
• The immunochemical titration of brain enzyme activity with antiretinal GS antibodies also revealed an immunological homology between retinal and brain enzymes [16].

References