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:4.1.1.15 (glutamate decarboxylase)
2,169 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The effect of selected potential inhibitors that may be found in water or wastewater on the activity of glutamate decarboxylase (EC 4.1.1.5) from Escherichia coli was determined. Several classes of compounds inhibited the enzyme, but those expected to be most frequently encountered were the heavy metal ions, the phosphates, and possibly the sulfates. From the results, it was judged that these compounds should not adversely affect the routine usage of this enzyme in an automated rapid test for E. coli.
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PMID:Effect of potential water pollutants and enzyme inhibitors on an automated rapid test for Escherichia coli. 79 Nov 28

Glutamate decarboxylase in extracts of barley has a Km value for L-glutamate of 22 mM and is activated by the addition of pyridoxal phosphate by up to 3.5 times. Sucrose-density-gradient experiments indicate the presence of two enzyme forms with molecular weights 256000 and 120000. The lower-molecular-weight form appears to be relatively inactive and spontaneously associates to the higher-molecular-weight form on storage. The enzyme is inhibited by thiol reagents and the distribution of activity on density gradients is altered in favour of the lower-molecular-weight form by the presence of 2-mercaptoethanol. After removal of the 2-mercaptoethanol spontaneous association to the higher-molecular-weight form occurs. The presence of oxygen in the extraction buffer and in the water during imbibition leads to a relative increase in the higher-molecular-weight form compared with situations where oxygen is excluded. In contrast, glutamate decarboxylase in extracts of 3-day-old barley roots has a Km value for L-glutamate of 3.1 mM and is activated up to 10% by addition of pyridoxal phosphate. The root enzyme occurs as a single species with molecular weight 310000 and this is unaffected by 2-mercaptoethanol although thiol reagents do act as weak inhibitors. The molecular weight is also unaffected by the presence or absence of oxygen in the extraction buffers.
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PMID:Glutamate decarboxylase from barley embryos and roots. General properties and the occurrence of three enzymic forms. 116 56

A very promising glutamate decarboxylase electrode, which has linear response range of 5.6 x 10(-5)-1.2 x 10(-2) mol/L. Nernstian slope of 50 mV/decade, detection limit of 3.2 x 10(-5) mol/L and response time less than 3 min, has been designed to observe and evaluate quantitatively the effect of magnetized water on enzyme activities by potentiometric enzyme electrode method. It was found that the activity of glutamate decarboxylase can increase by 30% in magnetized water. The mechanism of increased enzyme activity was discussed in the present paper. Such a new finding will probably lead to some new explanations for the physiological and biological mechanism of the effect of magnetized water on living organisms, thus providing a new approach to the study of the effect of magnetized water.
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PMID:A study of the effect of magnetized water on enzyme activities by potentiometric enzyme electrode method. 128 64

Rats were given unilateral infusions of ethylcholine aziridinium ion (AF64A) into the basal forebrain (BF). BF-lesioned rats had significant acquisition and retention deficits in two different types of learning tasks (water maze and active avoidance). Choline acetyltransferase activity was lower than control in the frontal cortex but not in the hippocampus or striatum. AF64A markedly reduced the levels of norepinephrine, dopamine, and serotonin in all brain regions studied. However, L-glutamic acid decarboxylase activity was not altered by AF64A injection. Cholinergic agents (physostigmine and arecoline) ameliorated the AF64A-induced learning deficits in the water maze task but not in the active avoidance task. Noncholinergic agents (desipramine and L-dopa) ameliorated the AF64A-induced avoidance deficits in the active avoidance task but not in the water maze task. 5-Methoxy-N,N-dimethyltryptamine did not improve either active avoidance or water maze learning. These results suggest that intra-BF injection of AF64A produces extensive brain dysfunction and that different neuronal systems are involved in associative and spatial learning.
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PMID:Learning deficits after unilateral AF64A lesions in the rat basal forebrain: role of cholinergic and noncholinergic systems. 152 35

We have recorded 1H NMR spectra in H2O for exchangeable protons of four pyridoxal phosphate-dependent enzymes: D-serine dehydratase, aspartate aminotransferase, tryptophan: indole-lyase and glutamate decarboxylase. The molecular masses range from 48-250 kDa. In every case there are downfield peaks which are lost when the apoenzyme is formed. In most cases some peaks shift in response to interactions with substrates and inhibitors and with changes in pH. We associate one downfield resonance with the proton on the ring nitrogen of the coenzyme and others with imidazole groups that interact with coenzyme or substrates. The chemical shift for the coenzyme-bound proton differs for free enzyme, substrate Schiff base or quinonoid forms.
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PMID:NMR spectra of exchangeable protons of pyridoxal phosphate-dependent enzymes. 206 76

2-Keto-3-fluoroglutaric acid prepared by acid hydrolysis of its diethyl ester is stable, as the free acid in aqueous solution at pH 2, and can be stored at -20 degrees C for several years. Both enantiomers are reduced by NADH in the presence of glutamate dehydrogenase (EC 1.4.1.2) to the two diastereomers of 3-fluoro-L-glutamate, which are stable at neutral pH and at high pH unless heated. 2-Keto-3-fluoroglutarate exists in solution almost entirely as a hydrate both at low and neutral pH. Both enantiomers of ketofluoroglutarate react with the pyridoxamine forms of aspartate, alanine and 4-aminobutyrate transaminases to give fluoride release. 2 mol of cosubstrate amino acid react for each mol of ketofluoroglutarate (KFG) when starting from the pyridoxamine form of the enzyme: 2 RCHNH2COOH + KFG + H2O----F- + NH4+ + glutamate + 2 RCOCOOH. Both diastereomers of fluoroglutamate are decarboxylated by glutamate decarboxylase (EC 4.1.1.15) with fluoride release: KFG + H2O----CO2 + F- + HCOCH2CH2COOH. By contrast, only one isomer of fluoroglutamate will react with the pyridoxal form of glutamate-oxalacetate transaminase to give fluoride release: HOOCCHNH2CHFCH2COOH + H2O----4F- + NH4+ + HOOCCOCH2CH2COOH. The enzymatic decarboxylation of 3-fluoroisocitrate produces only one enantiomer of ketofluoroglutarate, which is reduced to threo (2R,3R)-3-fluoroglutamate by NADH and glutamate dehydrogenase: [2R,3S]-HOOCCH(OH)CF(COOH)CH2COOH + NADP+----[3R]-KFG + CO2 + NADPH + H+. The proton, 13C, and 19F-NMR parameters of ketofluoroglutarate and the two fluoroglutamate diastereomers are presented. These molecules are useful probes of enzymatic mechanisms thought to involve carbanion intermediates.
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PMID:2-Keto-3-fluoroglutarate: a useful mechanistic probe of 2-keto-glutarate-dependent enzyme systems. 289 78

In rats receiving the gamma-aminobutyric acid (GABA)-transaminase inhibitor ethanolamine O-sulphate (EOS) in their drinking water for up to 28 days, the number of GABAA and GABAB binding sites was increased compared to controls. There was no change in binding affinity at GABAA or GABAB sites. One week after EOS withdrawal, the number of GABAA and GABAAB sites in previously treated EOS rats did not differ from controls. There was no difference in the number or affinity of benzodiazepine binding sites between EOS-treated and control rats during EOS administration or withdrawal. There was no difference in the stimulation of benzodiazepine binding by GABA (alone or in the presence of NaCl) during EOS administration. Cortical and cerebellar GABA concentration was increased 3.2- to 4.6-fold and cortical glutamate decarboxylase (GAD) activity reduced 30-42%. The current required to induce electroshock convulsions did not differ between EOS-treated rats and control rats during EOS administration. We speculate that the stimulus for the increased number of GABAA and GABAB binding sites is a reduction in GABA release subsequent to a reduction in GAD activity.
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PMID:Chronic administration of the GABA-transaminase inhibitor ethanolamine O-sulphate leads to up-regulation of GABA binding sites. 632 3

The stereochemistry of the decarboxylation of meso-alpha,epsilon-diaminopimelate catalyzed by meso-alpha,epsilon-diaminopimelate decarboxylase (EC 4.1.1.20) of Bacillus sphaericus was determined by stereochemical analyses of [6-2H]-L-lysine produced by the reaction in D2O. The product [6-2H]-L-lysine was converted to levorotatory methyl 5-phthalimido[5-2H]valerate by the reactions not affecting the absolute configuration of the asymmetric carbon atom. By contrast, methyl 5-phthalimido[5-2H]valerate derived from [2,6-2H2]-L-lysine, which was produced from [2,6-2H2]diaminopimelate by decarboxylation in H2O, was dextrorotatory. The authentic methyl (R)-5-phthalimido[5-2H]valerate prepared from L-glutamate with glutamate decarboxylase was levorotatory. These results indicate that the meso-alpha,epsilon-diaminopimelate decarboxylase reaction proceeds in an inversion mode. The deuterium label in [6-2H]-L-lysine was fully conserved during the conversion into pelletierine through [1-2H]cadaverine by the stereospecific diamine oxidase reaction. Thus, the enzymatic decarboxylation of meso-alpha,epsilon-diaminopimelate occurs with inversion of configuration in contrast to the other amino acid decarboxylase reported so far.
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PMID:Stereochemistry of meso-alpha,epsilon-diaminopimelate decarboxylase reaction: the first evidence for pyridoxal 5'-phosphate dependent decarboxylation with inversion of configuration. 679 66

The reaction of serine O-sulfate with cytosolic aspartate aminotransferase [John, R.A., & Fasella, P. (1969) Biochemistry 8, 4477] has been reinvestigated. As in the corresponding reaction with beta-chloroalanine [Morino, Y., Osman, A.M., & Okamoto, M. (1974) J. Biol. Chem. 249, 6684], the enzyme is inactivated over a 10-min period, and the absorption maximum at pH 5.4 shifts from 430 to 336 nm. Upon prolonged standing the peak shifts again over a period of 20 h to 455 nm, a behavior entirely similar to that reported by Morino et al. for beta-chloroalanine in the presence of 3 M formate. When the pH of either the 10-min product (1a) or the 20-h product (1b) is raised to 11 or above, a yellow, diffusible compound (2) is released from the protein. This compound as well as its dephosphorylation and reduction products has been isolated and studied by NMR spectroscopy. Compound 2 is identical with a compound formed from serine sulfate and glutamate decarboxylase by a similar reaction sequence [Likos, J.J., Ueno, H., Feldhaus, R.W., & Metzler, D.E. (1982) Biochemistry (preceding paper in this issue)] and is the product of an aldol condensation of pyruvate with pyridoxal phosphate. When the 20-h product 1b is reduced with sodium borohydride and then heated in a boiling water bath, a material identical with the reduction product of 2 is released. We propose that the 20-h product 1b consists of 2 bound to the enzyme. Pathways for the formation of the various compounds are proposed. These findings require a reevaluation of the mechanisms of action of many enzyme-activated inhibitors of pyridoxal phosphate dependent enzymes.
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PMID:Chemistry of the inactivation of cytosolic aspartate aminotransferase by serine O-sulfate. 681 25

Ethanolamine O-sulphate (EOS) dissolved in the drinking water (5 mg . ml(-1) was administered ad libitum to rats for 26 days. At the end of this period, glutamate decarboxylase (GAD) and GAA-transaminase (GABA-T) activities, 4-aminobutyrate (GABA) concentration, and the levels of six other amino acids were measured in various brain regions. Significant inhibition of GABA-T accompanied by significant increases in GABA content were observed throughout the brain, although the magnitudes of these effects varied according to region. GAD activity was significantly reduced in most brain regions, although this effect was apparently not related to cofactor availability or the direct actions of EOS or increased GABA concentration. Glutamine levels were significantly reduced to approximately 72% of control values in all brain regions. Aspartate levels were significantly reduced to approximately 84% of control values in all regions except the striatum and cerebellum. Minor changes in other amino acid levels were also detected. These neurochemical changes which accompanied the primary effect of EOS on GABA-T are discussed in terms of indirect secondary metabolic changes rather than nonspecific enzyme inhibition by EOS.
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PMID:A regional study of 4-aminobutyrate metabolism and amino acid levels in rat brain following chronic oral administration of ethanolamine O-sulphate. 706 27


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