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:1.2.1.13 (glyceraldehyde-3-phosphate dehydrogenase)
6,511 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Aggregation of glyceraldehyde-3-P dehydrogenase (NADP) (EC 1.2.1.13) from Sinapis alba seedlings during gel filtration on Sepharose 6B is dependent on the presence of a fraction ("binding fraction") which can be separated from the enzyme by precipitation with 55% ammonium sulfate. Association of the enzyme with this binding fraction is NAD-dependent whereas NADP(+) causes release. Dithioerythritol (2 mM) has no influence on these reversible processes.Binding fractions, partially purified by ammonium sulfate and acetone fractionation, were submitted to dodecylsulfate-polyacrylamide gel electrophoresis. They always contain one or two dominant polypeptides with apparent molecular weights 42,000 and 58,000. The 42,000 polypeptide comigrates during dodecylsulfate electrophoresis with the corresponding subunit of the enzyme. It comprises up to 70% of the total protein in partially purified binding fractions and can be regarded as a major protein in seedling extracts.The differential transport behavior of glyceraldehyde-3-P dehydrogenase (NADP) on Sephadex G-200 in the presence of NAD(+) and NADP(+) can be used as a simple and effective purification procedure. The enzyme isolated in this way has an isoelectric point of about 4.5 and maintains under all tested conditions a heterogeneous subunit composition of at least three different polypeptide chains (apparent molecular weights, 39,000, 42,000, 43,000).The present data suggest that NAD(P)-controlled aggregation of glyceraldehyde-3-P dehydrogenase (NADP) from Sinapis alba L. is due primarily to enzyme association with a separate binding fraction rather than to enzyme polymerization. It is possible that a major component of this binding fraction, the 42,000 polypeptide, consists of "surplus" nonactive enzyme subunits, which self-associate and interact with the NAD-conformer of the enzyme.
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PMID:Glyceraldehyde-3-Phosphate Dehydrogenase (NADP) from Sinapis alba L: Reversible Association of the Enzyme with a Protein Factor as Controlled by Pyridine Nucleotides in Vitro. 1666 Feb 95

Mesembryanthemum crystallinum, a halophilic, inducible Crassulacean acid metabolism (CAM) species, was grown at NaCl concentrations of 20 and 400 millimolar in the rooting medium. Plants from the low salinity treatment showed exclusively C(3)-photosynthetic net CO(2) fixation, whereas plants exposed to the high salinity level exhibited net CO(2) dark fixation involving CAM. Mesophyll protoplasts, isolated from both tissues, were gently ruptured, and the intracellular localization of enzymes was studied following differential centrifugation and Percoll density gradient centrifugation of protoplast extracts. Both centrifugation techniques resulted in the separation of intact chloroplasts, with up to 90% yield, from other organelles and the nonparticulate fraction of cells. Enzymes were identified by determination of activity and by sodium dodecyl sulfate gel electrophoresis of enzyme protein.Experiments established the extraorganellar (cytoplasmic) location of phosphoenolpyruvate carboxylase, enolase, phosphoglyceromutase, and NADP-malic enzyme; the mitochondrial location of NAD-malic enzyme; and the chloroplastic location of pyruvate, Pi dikinase. NAD-glyceraldehyde-3-phosphate dehydrogenase, phosphohexose isomerase, and phosphoglycerate kinase were associated with both cytoplasm and chloroplasts. NADP-dependent malate dehydrogenase activity was found in both the chloroplastic and extrachloroplastic fractions; the activity in the chloroplast showed an optimum at pH 8.0 and was dependent upon preincubation of enzyme with dithiothreitol. The extrachloroplastic activity showed an optimum at pH 6.5 and was independent of pretreatment with dithiothreitol. Protoplast extracts of M. crystallinum performing CAM exhibited higher activities (expressed per mg chlorophyll per min) of phosphoenolpyruvate carboxylase, pyruvate, Pi dikinase, NADP-malic enzyme, NAD-malic enzyme, NADP-malate dehydrogenase, enolase, phosphoglyceromutase, NAD-glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and phosphohexose isomerase than protoplast extracts from M. crystallinum not exhibiting CAM. The increase in total activity of the latter three enzymes following exposure of plants to 400 millimolar NaCl and the development of CAM was due to specific increases in the levels of activity in the cytoplasm.
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PMID:Intracellular Localization of Enzymes of Carbon Metabolism in Mesembryanthemum crystallinum Exhibiting C(3) Photosynthetic Characteristics or Performing Crassulacean Acid Metabolism. 1666 97

The crystal structure of NADP-dependent apo-glyceraldehyde-3-phosphate dehydrogenase (apo-GAPDH) from Synechococcus PCC 7942 is reported. The crystal structure was solved by molecular replacement and refined to an R of 21.7% and R(free) of 27.5% at 2.9 angstroms resolution. The structural features of apo-GAPDH are as follows. The S-loop has an extremely flexible conformation and the sulfate ion is only taken into the classical P(i) site. A structural comparison with holo-GAPDHs indicated that the S-loop fixation is essential in the discrimination of NADP and NAD molecules.
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PMID:Structure of apo-glyceraldehyde-3-phosphate dehydrogenase from Synechococcus PCC7942. 1688 May 42

The female gamete, the egg cell, is a specially differentiated haploid cell that develops into an embryo following fertilization. In the present study, we analyzed egg cell lysates by sodium dodecyl sulfate-polyacrylamide gel electrophoresis and subsequent mass spectrometry-based proteomics technology and identified the major proteins expressed in rice egg cells. The proteins identified included glyceraldehyde-3-phosphate dehydrogenase, ascorbate peroxidase and heat shock protein 90. The abundant existence of chaperons and antioxidant enzymes in plant egg cells indicates that the major protein components of plant egg cells are partly analogous to those of mammalian eggs and oocytes.
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PMID:Identification of the major protein components of rice egg cells. 1755 43

Arsenate (As(V)) is reduced in the body to the more toxic arsenite (As(III)). We have shown that two enzymes catalyzing phosphorolytic cleavage of their substrates, namely purine nucleoside phosphorylase and glyceraldehyde-3-phosphate dehydrogenase, can reduce As(V) in presence of an appropriate thiol and their substrates. Another phosphorolytic enzyme that may also reduce As(V) is glycogen phosphorylase (GP). With inorganic phosphate (P(i)), GP catalyzes the breakdown of glycogen to glucose-1-phosphate; however, it also accepts As(V). Testing the hypothesis that GP can reduce As(V), we incubated As(V) with the phosphorylated GPa or the dephosphorylated GPb purified from rabbit muscle and quantified the As(III) formed from As(V) by high-performance liquid chromatography-hydride generation-atomic fluorescence spectrometry. In the presence of adenosine monophosphate (AMP), glycogen, and glutathione (GSH), both GP forms reduced As(V) at rates increasing with enzyme and As(V) concentrations. The As(V) reductase activity of GPa was 10-fold higher than that of GPb. However, incubating GPb with GP kinase and ATP (that converts GPb to GPa) increased As(V) reduction by phosphorylase up to the rate produced by GPa incubated under the same conditions. High concentration of inorganic sulfate, which activates GPb like phosphorylation, also promoted reduction of As(V) by GPb. As(V) reduction by GPa (like As(V) reduction in rats) required GSH. It also required glycogen (substrate for GP) and was stimulated by AMP (allosteric activator of GP) even at low micromolar concentrations. P(i), substrate for GP competing with As(V), inhibited As(III) formation moderately at physiological concentrations. Glucose-1-phosphate, the product of GP-catalyzed glycogenolysis, also decreased As(V) reduction. Summarizing, GP is the third phosphorolytic enzyme identified capable of reducing As(V) in vitro. For reducing As(V) by GP, GSH and glycogen are indispensable, suggesting that the reduction is linked to glycogenolysis. While its in vivo significance remains to be tested, further characterization of the GP-catalyzed As(V) reduction is presented in the adjoining paper.
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PMID:Glutathione-dependent reduction of arsenate by glycogen phosphorylase a reaction coupled to glycogenolysis. 1769 25

The NAD+-dependent cytosolic glyceralehyde-3-phosphate dehydrogenase (GAPDH; EC 1.2.1.12) was purified from the skeletal muscle of European pilchard Sardina pilchardus and its physicochemical and kinetic properties were investigated. The purification method consisted of two steps, ammonium sulfate fractionation followed by Blue Sepharose CL-6B chromatography, resulting in an approximately 78-fold increase in specific activity and a final yield of approximately 25%. The Michaelis constants (K(m)) for NAD+ and D-glyceraldehyde-3-phosphate were 92.0 microM and 73.4 microM, respectively. The maximal velocity (V(max)) of the purified enzyme was estimated to be 37.6 U/mg. Under the assay conditions, the optimum pH and temperature were 8.0 and 30 degrees C. The molecular weight of the purified enzyme was 37 kDa determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Non-denaturing polyacrylamide gels yielding a molecular weight of 154 kDa suggested that the enzyme is a homotetramer. Polyclonal antibodies against the purified enzyme were used to recognize the enzyme in different sardine tissues by Western blot analysis. The isoelectric point, obtained by an isoelectric focusing system in polyacrylamide slab gels, revealed only one GAPDH isoform (pI 7.9).
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PMID:Purification and characterization of glyceraldehyde-3-phosphate dehydrogenase from European pilchard Sardina pilchardus. 1806 87

Connexin43 (Cx43) is the predominant intercellular gap junction protein in the heart providing intercellular communication for the cell-to-cell transfer of electrical activation. In a previous study, we could show that alpha-adrenoceptor stimulation can affect Cx43 expression and function. We now wanted to elucidate which alpha1-adrenoceptor subtype might be involved. Cultured neonatal rat cardiomyocytes were exposed to various concentrations of phenylephrine (0.1-1,000 nM) for 24 h (n=6). Thereafter, cells were harvested, and after lysis, Cx43 content was determined using sodium dodecyl sulfate polyacrylamide gel electrophoresis and Western blot. Results were normalised to glyceraldehyde-3-phosphate dehydrogenase (GAPDH). Finally, we determined the effect of this treatment on intercellular gap junction conductivity using dual whole-cell voltage clamp. Similarly, we tested the effect of an additional treatment with either 10 nM prazosin or, to assess the subtypes, 10 nM of the alpha(1A)-antagonist RS17053 (n=6), 500 nM of the alpha(1B)-antagonist AH1111OA (n=6), or 50 nM of the alpha(1D)-antagonist BMY7378 (n = 6). Moreover, we incubated the cells for 24 h with the alpha(1A)-adrenoceptor agonist A61603 (10 nM). Phenylephrine led to enhanced Cx43 expression with a pEC50 8.00+/-0.06. The other cardiac connexins, Cx40 and Cx45, as well as GAPDH were not affected. This increase in Cx43 expression resulted in enhanced gap-junction conductance (44+/-4 nS vs 26+/-4 nS). As expected, the increased Cx43 expression could be antagonized by prazosin. Moreover, it was nearly completely inhibited by BMY7378 but was not significantly affected by RS17053. AH1111OA led to a moderate but incomplete inhibition. In contrast, beta-actin expression was also up-regulated by phenylephrine but was inhibited by prazosin or RS17053, while it was not affected by BMY7378 or AH1111OA. About 24 h exposure to the alpha(1A)-adrenoceptor agonist A61603 led to a twofold increase in beta-actin but did not affect Cx43. The low pEC50 value of about 1 nM for noradrenaline reported in our earlier study fits well to the hypothesis of an effect mediated predominantly via alpha(1D)-adrenoceptors, which is further supported by the finding of a nearly complete antagonisation of the phenylephrine effect by BMY7378. Thus, we conclude that cardiac Cx43 expression seems to be regulated via alpha(1)-adrenoceptors predominantly by subtype alpha(1D)-adrenoceptors, while other proteins like beta-actin seem to be regulated via alpha(1A)-adrenoceptors.
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PMID:Alpha-1-adrenoceptor subtype selective regulation of connexin 43 expression in rat cardiomyocytes. 1819 2

The effect of several factors on the activity and stability of alcohol dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and 20beta-hydroxysteroid dehydrogenase, both free and immobilized on CNBr-activated Sepharose 4B, was investigated. Enzymes were im- mobilized under different conditions including various degrees of matrix activation, variable amounts of protein, in the presence, or in the absence of, additives (coenzymes, dithioth- reitol, salts). Activity recovery was in general satisfactorily high with 20beta-hydroxysteroid dehydrogenase, low with glyceraldehyde-3-phosphatedehydrogenase, and markedly linked to the concentration of immobilized protein with alcohol dehydrogenase. In the latter case the advantageous stabilizing effect of high enzyme concentrations was notably diminished by the parallel decrease of the effectiveness factor. The effect of high concentrations of anions of the Hofmeister series was examined. It was found that 1M phosphate and 0.5M sulfate dramatically stabilize both free and immobilized enzymes against inactivation by temperature and urea. K(m), values of apolar substrates were considerably lowered by the two anions while K(m) values of polar substrates were not affected. In some cases V(max) values also were influenced by high concentrations of these anions. The present results appear of interest particularly in view of enzyme utilization for analytical as well as for preparative purposes.
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PMID:The effect of Hofmeister anions and protein concentration on the activity and stability of some immobilized NAD-dependent dehydrogenases. 1854 96

A new procedure utilizing immunoaffinity column chromatography has been used for the purification of glyceraldehyde-3-phosphate dehydrogenase (GAPDH, EC 1.2.1.12) from human erythrocytes. The comparison between this rapid method (one step) and the traditional procedure including ammonium sulfate fractionation followed by Blue Sepharose CL-6B chromatography shows that the new method gives a highest specific activity with a highest yield in a short time. The characterization of the purified GAPDH reveals that the native enzyme is a homotetramer of ~150 kDa with an absolute specificity for the oxidized form of nicotinamide adenine dinucleotide (NAD(+)). Western blot analysis using purified monospecific polyclonal antibodies raised against the purified GAPDH showed a single 36 kDa band corresponding to the enzyme subunit. Studies on the effect of temperature and pH on enzyme activity revealed optimal values of about 43 degrees C and 8.5, respectively. The kinetic parameters were also calculated: the Vmax was 4.3 U/mg and the Km values against G3P and NAD(+) were 20.7 and 17.8 muM, respectively. The new protocol described represents a simple, economic, and reproducible tool for the purification of GAPDH and can be used for other proteins.
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PMID:Immunoaffinity purification and characterization of glyceraldehyde-3-phosphate dehydrogenase from human erythrocytes. 1943 Jul 4

Cyclophilins are conserved cis-trans peptidyl-prolyl isomerase that are implicated in protein folding and function as molecular chaperones. We found the expression of cyclophilin A, Cpr1, changes in response to exposure to yeast Saccharomyces cerevisiae to abiotic stress conditions. The effect of Cpr1 overexpression in stress responses was therefore examined. The CPR1 gene was cloned to the yeast expression vector pVTU260 under regulation of an endogenous alcohol dehydrogenase (ADH) promoter. The overexpression of Cpr1 drastically increased cell viability of yeast in the presence of stress inducers, such as cadmium, cobalt, copper, hydrogen peroxide, tert-butyl hydroperoxide (t-BOOH), and sodium dodecyl sulfate (SDS). The Cpr1 expression also enhanced the cell rescue program resulting in a variety of antioxidant enzymes including thioredoxin system (particularly, thioredoxin peroxidase), metabolic enzymes (glucose-6-phosphate dehydrogenase and glyceraldehyde-3-phosphate dehydrogenase), and molecular chaperones (Hsp104, Hsp90, Hsp60 and Hsp42). Thus, our study illustrates the importance of Cpr1 as a molecular chaperone that improves cellular stress responses through collaborative relationships with other proteins when yeast cells are exposed to adverse conditions, and it also premises the improvement of yeast strains.
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PMID:A cyclophilin A CPR1 overexpression enhances stress acquisition in Saccharomyces cerevisiae. 2049 20


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