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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)

Rabbit muscle glyceraldehyde-3-phosphate dehydrogenase covalently bound to Sepharose was shown to form a complex with soluble 3-phosphoglycerate kinase. The strength of the association appeared to depend upon the functional state of both enzymes. The holoform of the dehydrogenase exhibited a lower affinity for the kinase than the enzyme-3-phosphoglycerol.NADH complex. The substrate-free 3-phosphoglycerate kinase associated much stronger with the acylated dehydrogenase than the kinase in complex with 1,3-diphosphoglycerate. Electron-microscopic evidence for the association of the soluble acyl-glyceraldehyde-3-phosphate dehydrogenase.NADH complex and 3-phosphoglycerate kinase was also obtained.
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PMID:Association of rabbit muscle glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase. The biochemical and electron-microscopic evidence. 316 48

It has been shown recently that glyceraldehyde-3-phosphate dehydrogenase (GAPD) is one of the three major RNA-binding proteins of rabbit reticulocytes [Ryazanov, A. G. (1985) FEBS Lett. 192, 131-134]. It was suggested that, due to its RNA-binding capacity, GAPD can form loose dynamic complexes with polyribosomes. This communication reports that a considerable amount of GAPD activity can be found in the mono- and polyribosome fraction after sucrose gradient centrifugation of rabbit reticulocyte lysate. An increase of ionic strength, as well as the addition of exogenous RNA to the extract, result in the removal of GAPD from the complex with mono- and polyribosomes. It appears that GAPD forms the complex with polyribosomes due to the interaction with some exposed RNA regions of these structures. Although the interaction of GAPD with ribosomes is weak, it can be detected under physiological ionic conditions by the difference boundary sedimentation velocity technique. Association of GAPD with mono- and polyribosomes can be prevented by a low concentration (10 microM) of NADH, but not NAD+. A nitrocellulose filter binding assay also shows that NADH has a stronger inhibitory effect on the enzyme-RNA complex formation, as compared with NAD+. We propose that the RNA-mediated association of GAPD with mono- and polyribosomes can provide compartmentation of the energy-supplying system on these structures within the cell. This can maintain a high local concentration of ATP and GTP near the sites of protein synthesis.
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PMID:Association of glyceraldehyde-3-phosphate dehydrogenase with mono- and polyribosomes of rabbit reticulocytes. 327 18

A radiometric method has been devised for the determination of small quantities of NADH formed in preceding dehydrogenase reactions. In a coupled enzymatic reaction, phosphoglycerate kinase (PGK) catalyzes the transfer of [32P]orthophosphate from [gamma-32P]ATP to 3-phosphoglycerate; the intermediate, 1,3-[1-32P]diphosphoglycerate, is dephosphorylated by glyceraldehyde-3-phosphate dehydrogenase (GAP-DH). [32P]Orthophosphate is released proportionally to NADH and can be measured after adsorption of [gamma-32P]ATP to activated charcoal. With this method, 0.2 pmol of NADH are detectable in the presence of a 10(4)-fold excess of NAD over NADH.
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PMID:A radiometric method for the determination of NADH in subpicomole amounts. 337 44

A detailed study of the glucose fermentation pathway and the modulation of catabolic oxidoreductase activities by energy sources (i.e., glucose versus lactate or fumarate) in Propionispira arboris was performed. 14C radiotracer data show the CO2 produced from pyruvate oxidation comes exclusively from the C-3 and C-4 positions of glucose. Significant specific activities of glyceraldehyde-3-phosphate dehydrogenase and fructose-1,6-bisphosphate aldolase were detected, which substantiates the utilization of the Embden-Meyerhoff-Parnas path for glucose metabolism. The methylmalonyl coenzyme A pathway for pyruvate reduction to propionate was established by detection of significant activities (greater than 16 nmol/min per mg of protein) of methylmalonyl coenzyme A transcarboxylase, malate dehydrogenase, and fumarate reductase in cell-free extracts and by 13C nuclear magnetic resonance spectroscopic demonstration of randomization of label from [2-13C]pyruvate into positions 2 and 3 of propionate. The specific activity of pyruvate-ferredoxin oxidoreductase, malate dehydrogenase, fumarate reductase, and transcarboxylase varied significantly in cells grown on different energy sources. D-Lactate dehydrogenase (non-NADH linked) was present in cells of P. arboris grown on lactate but not in cells grown on glucose or fumarate. These results indicate that growth substrates regulate synthesis of enzymes specific for the methylmalonyl coenzyme A path and initial substrate transformation.
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PMID:Regulation of carbon and electron flow in Propionispira arboris: relationship of catabolic enzyme levels to carbon substrates fermented during propionate formation via the methylmalonyl coenzyme A pathway. 341 Aug 21

The rate of 3-phosphoglycerate kinase reaction carried out under the conditions of saturating substrate concentrations (10 mM 3-phosphoglycerate, 3 mM ATP) and 0.2 mM NADH is increased in the presence of glyceraldehyde-3-phosphate dehydrogenase. This effect is probably due to the acceleration of 1.3-diphosphoglycerate transfer in the bienzyme complex (Weber and Bernhard, Biochemistry, 21,4189-4194, 1982). An analysis of the dependence of the rate constant of the coupled 3-phosphoglycerate kinase- glyceraldehyde-3-phosphate dehydrogenase reaction on the concentration of the latter enzyme was used to estimate the apparent Kd of the bienzyme complex. Under the conditions employed in this study (MOPS, 20 mM pH 7.2, 25 degrees C) this value was found to correspond to (2.5 +/- 0.6). 10(-8)M.
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PMID:Kinetic evidence for the interaction between rabbit muscle D-glyceraldehyde-3-phosphate dehydrogenase and 3-phosphoglycerate kinase. 343 30

NADH and NADPH accelerate the 'in vitro' rate of proteolysis of glyceraldehyde-3-phosphate dehydrogenase (GAPDH) by elastase and other proteases, including lysosomal proteases. NAD+ and NADP+ have the opposite effect. Since there is a good correlation between proteolytic susceptibility of proteins and their 'in vivo' degradation rates, a possible role of the reduction-oxidation status in controlling the intracellular degradation of GAPDH is advanced.
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PMID:The reduction-oxidation status may influence the degradation of glyceraldehyde-3-phosphate dehydrogenase. 353 Aug 13

The review summarizes the results of a study on the functional role of subunit interactions in a tetrameric glyceraldehyde-3-phosphate dehydrogenase molecule. A conformational asymmetry preexistent in the apoenzyme was shown to be detectable with the use of fluorescent cationic probes. Experimental evidence is presented which points to an interaction of the enzyme active centers in the course of productive E-acyl-NADH complex formation in the forward reaction. The matrix immobilized oligomeric and subunit forms of the enzyme were used to demonstrate that the quaternary structure is not a prerequisite for the catalytic activity. Due to subunit interactions within the oligomeric enzyme molecule the functioning of a monomer is under the control exerted by the neighbouring subunits. An association of monomers into a dimer is sufficient to create a cooperative system; the mutual influence of subunits becomes more complex in a trimeric and a tetrameric enzyme species. An isolated dimer exhibits the effect of half-of-the-sites reactivity and catalytic cooperativity of the active centers. Both the tetrameric and dimeric enzyme forms probably catalyze the reaction of 1,3-diphosphoglycerate reductive dephosphorylation via a mechanism of the flip-flop type. The catalytic cooperativity of the enzyme active centers can be controlled by some factors of the intracellular environment (e.g., by protein-protein interactions with a functionally related enzyme). Thus, the role of subunit cooperativity in the glyceraldehyde-3-phosphate dehydrogenase molecule is suggested to constitute one of the mechanisms of regulation of the enzyme functioning.
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PMID:[The role of oligomeric structure in the functioning of D-glyceraldehyde-3-phosphate dehydrogenase]. 354 63

Fructose-1,6-bisphosphate and triosephosphates have been separated by high performance liquid chromatography utilizing a SynChropack AX anion exchange column with 50-200 mM KH2PO4, pH 2.5-4.6 as mobile phase. The best resolution for each compound was reached in a system of 150 mM KH2PO4, pH 2.5. If radioactive fructose-1,6-bisphosphate as initial substrate was enzymatically converted in triosephosphates, the recoveries of metabolites after the precipitation and chromatographic procedures were higher than 95%. The concentration of radioactive 3-phosphoglycerate measured by liquid scintillation shows a good correlation (correlation coefficient: 0.997) with the spectrophotometrically determined concentration of NADH, which is formed from [U-14C]fructose-1,6-bisphosphate in equimolar concentration with 3-phosphoglycerate in aldolase and glyceraldehyde-3-phosphate dehydrogenase system. The method developed was applied to detect the inhibitory effect of triosephosphate isomerase on aldolase activity which takes place due to the heterologous complex formation.
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PMID:Quantitative determination of triosephosphates during enzymatic reaction by high performance liquid chromatography: effect of isomerase on aldolase activity. 355 36

In the process of defining the recruitment of fuel and pathway selection in rainbow trout fast-twitch white skeletal muscle, it was clear that the near-maximal myosin adenosinetriphosphatase activity during a 10-s sprint was supported solely by phosphocreatine hydrolysis. A conservative estimate of the ATP turnover was 188 mumol X g wet wt-1 X min-1. It was not until the rate and force of contraction decreased that the relative contribution of anaerobic glycogenolysis became increasingly important. Over a 10-min period of burst swimming at approximately 120% of maximum aerobic steady-state swimming velocity of trout determined in a Brett-type swim tunnel, fatigue was associated with the near-depletion of glycogen in white muscle. The ATP turnover supported by anaerobic glycogenolysis was 78 mumol X g wet wt-1 X min-1. The glycolytic pathway appeared functional at this time with control sites being identified at hexokinase and phosphofructokinase (PFK-1). PFK-1 did not appear to be inhibited by low muscle pH (pH 6.66). In another exercise protocol lasting 30 min, complete exhaustion was related to glycogen depletion. The sum of all glycolytic intermediates from glucose 6-phosphate to pyruvate at exhaustion decreased by a dramatic 80% compared with the 25% decrease for the 10-min fatigue swimming protocol. This large depletion of glycolytic intermediates was accompanied by an 80% fall in ATP, a 70-80% reduction in the ATP/ADP and phosphorylation potential, and a 2.5-fold increase in the NAD/NADH. Associated with these changes was a marked displacement of the phosphoglycerate kinase (PGK), and the combined glyceraldehyde-3-phosphate dehydrogenase-PGK reactions from thermodynamic equilibrium. As a general conclusion, fatigue and exhaustion should be viewed as a multicomponent biochemical process in response to low glycogen and not leveled at one particular step of the glycolytic pathway.
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PMID:Regulation of anaerobic ATP-generating pathways in trout fast-twitch skeletal muscle. 360 83

The metabolism of [2-3H]lactate and [2-3H]glycerol was studied in isolated hepatocytes from fed rats. In order to estimate the rate of equilibrium between the 4A and 4B hydrogen atoms of NADH, we compared the flow of 3H from [2-3H]lactate and [2-3H]glycerol, the oxidations of which are catalysed by A- and B-type dehydrogenases, respectively. Hepatocytes were incubated with lactate, glycerol and ethanol and tracer amounts of [2-3H]lactate or [2-3H]glycerol and the labelling rates of lactate, ethanol, glucose and glycerol phosphate were determined. The data were used to calculate the oxidation rate of NADH catalysed by lactate dehydrogenase, alcohol dehydrogenase, triosephosphate dehydrogenase and glycerol phosphate dehydrogenase. The rates were calculated by obtaining the best fit of a model to the experimental data by using a least-squares procedure. The results support our model and suggest that the fluxes through various dehydrogenases are sufficient to equilibrate the 4A and 4B hydrogen atoms of cytosolic NADH. The validity of the metabolic models used was evaluated by comparison of rates of NADH oxidation catalysed by cytosolic dehydrogenases as calculated by two different models.
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PMID:Pathways of reducing equivalents in hepatocytes from rats. Estimation of cytosolic fluxes by means of 3H-labelled substrates for either A- or B-specific dehydrogenases. 366 93


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