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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)

Glyceraldehyde-phosphate dehydrogenase (D-glyceraldehyde-3-phosphate : NADP+ oxidoreductase (phosphorylating), EC 1.2.1.13) from spinach chloroplasts is a polymeric protein of approx. 600,000 daltons and sodium dodecyl sulphate gel electrophoresis shows that it consists of two subunits of molecular weight 43,000 and 37,000. Comparison of amino acid analyses and tryptic peptide maps indicates that the two subunits have a different primary structure. The native enzyme contains 0.5 mol of NADP+ and 0.5 mol of NAD+ per protomer of 80,000 daltons, no reduced pyridine nucleotides have been detected. Almost complete inactivation is obtained by reaction of two cysteinyl residues per 80,000 daltons with tetrathionate or iodo[14C2]acetic acid; since the same amount of radioactivity is incorporated in the two subunits it is likely that they are both essential for the catalytic activity. Charcoal stripping of native glyceraldehyde-phosphate dehydrogenase produces an apoprotein which still retains most of the enzymatic activity but, unlike the holoenzyme, is gradually inactivated by storage at 4 degrees C and does not react with iodoacetate under the same conditions in which the holoenzyme is completely inactivated.
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PMID:Subunit structure and activity of glyceraldehyde-3-phosphate dehydrogenase from spinach chloroplasts. 2 61

In a previous publication (Cerff, R. (1979) Eur. J. Biochem., 94, 243--247) we demonstrated that chloroplast NADP-linked glyceraldehyde-3-P dehydrogenase (EC 1.2.1.13) from higher plants consists of two separate isoenzymes with apparent subunit compositions A2B2 (isoenzyme 1) and A4 (isoenzyme 2), where Subunits A and B are distinguished by slightly different molecular weights (A smaller than or approximately to B). In the present study we compare isoenzymes 1 and 2 from Sinapis alba and Hordeum vulgare on the basis of antigenic cross-reactivity, tryptic peptides, and amino acid composition. Isoenzymes 1 and 2 show immunochemical identity. They also have very similar tryptic peptide maps and amino acid compositions. This strongly suggests that Subunits A and B of the NADP-linked enzyme are very similar in primary sequence. As opposed to this, cytoplasmic NAD-specific glyceraldehyde-3-P dehydrogenase (EC 1.2.1.12) does not cross-react with antisera raised against the NADP-linked enzyme. Furthermore, tryptic peptide maps of the NAD-specific enzyme show little or no similarity with those of the NADP-linked enzyme. This indicates that the subunits of the NADP-linked enzyme and the subunit of the NAD-specific enzyme are different proteins coded by separate genes. The differences in the amino acid compositions between the two species corresponds to a SdeltaQ value of 21, suggesting some sequence resemblance and a common phylogenetic origin.
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PMID:Subunit structure of higher plant glyceraldehyde-3-phosphate dehydrogenases (EC 1.2.1.12 and EC 1.2.1.13). 10 46

The kinetic method and selective chemical modification have been used in studies of the kinetic manifestations of active site interactions in D-glyceraldehyde-3-phosphate dehydrogenase (GAP dehydrogenase). The reactions of glyceraldehyde and glyceraldehyde-3-phosphate oxidation were studied in the absence of substrate excess. In support of the data obtained previously it was shown that only a part of the tightly bound NAD molecules can be reduced after substrate addition. "Partial reducibility" is observed at various degrees of saturation of the enzyme with NAD involving a single NAD molecule per tetrametric enzyme. These facts can hardly be explained by assumption of functional non-equivalence of active sites, whether induced by coenzyme or preexisting in the apoenzyme. It was proven by selective alkylation of the catalytic SH groups that "partial reducibility" is due to the circumstance that equilibrium in the system under investigation is established at nearly equal NAD and NADH concentrations. A plot of initial reaction rates versus NAD concentration (at non-saturating substrate concentrations) gives S-shaped curves; this is explained by considerable enzyme activation upon saturation of the fourth site with coenzyme. After modification of three active sites with iodoacetate the S-shape of the curve disappeared. This fact leads to the conclusion that active site interactions are required for formation of the S-shaped curves. The activity of a single site functioning in the modified enzyme reached values equal to those of the active sites in the native enzyme in the fully activated state. A model is proposed which can explaine the variations in mode of enzyme activation in the native and modified states. It is suggested that the surroundings of all four SH groups must be altered in order to activate the enzyme; such changes can be induced either by alkylation of the SH groups or by NAD binding. Evidence is presented that important functional properties of GAP dehydrogenase cannot be elucidated at low enzyme concentrations and with excess of substrates: three active sites are saturated under such conditons and practically inactive, and the fourth site obeys Michaelis - Menten kinetics.
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PMID:[Kinetic manifestations of the interaction of active centers in swine skeletal muscle D-glyceraldehyde-3-phosphate dehydrogenase]. 18 4

Activities of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12) (GAP-DH) and aldolase (EC 4.1.2.13) in cells of Clostridium perfringens that had been inhibited with sodium nitrite were investigated. A complete loss in GAP-DH activity and a 67% decrease in aldolase activity were observed when growth of C. perfringens was inhibited. There was also a 91% decrease in the concentration of free sulfhydryl groups of soluble cellular components. Dithiothreitol restored some activity to inactive GAP-DH from sodium nitrite-inhibited cells, indicating that a loss of reduced sulfhydryl groups was involved in the inactivation of the enzyme. The evidence presented suggests that sodium nitrite inhibition of C. perfringens may involve an interaction of sodium nitrite as nitrous acid with sulfhydryl-containing constituents of the bacterial cell.
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PMID:Effect of sodium nitrite inhibition on intracellular thiol groups and on the activity of certain glycolytic enzymes in Clostridium perfringens. 18 14

The NH2-terminal amino acid sequence of rat skeletal muscle glyceraldehydephosphate dehydrogenase (D-glyceraldehyde-3-phosphate : NAD+ oxidoreductase(physphorylating), EC 1.2.1.12) was determined to be Val-Lys-Val-Gly-Val-Asn-Gly-Phe-Gly-Arg-Ile-Gly-Arg-Leu-Val-Thr-Arg-Ala-Ala-Phe-Ser-Ser-(-)-(-)--Val-Asx-Ile-Val-Ala-Ile. The presence of Asn instead of Asp in position 6 differentiates this enzyme from other glyceraldehyde-3-phosphate dehydrogenases so far sequenced with the exception of the enzymes isolated from liver. The location of Asn in position 6 has been considered as a specific property of liver glyceraldehyde-3-phosphate dehydrogenase (Kulbe, K.D., Jackson, K.W. and Tang, J. (1975) Biochem. Biophys. Res. Commun. 67, 35--42); this suggestion is not sustained by the results of the present investigation. The amino acid composition of the rat skeletal muscle dehydrogenase demonstrates the unusually low histidine content of this enzyme as compared to other mammalian muscle glyceraldehyde-phosphate dehydrogenases.
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PMID:Structural studies on glyceraldehyde-phosphate dehydrogenase from rat skeletal muscle. 62 46

The five glycolytic enzymes glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, phosphoglycerate mutase, enolase and pyruvate kinase were each purified from extracts of Zymomonas mobilis cells, by using dye-ligand chromatography as the principal step. Two procedures, producing three and two of the enzymes respectively, are described in detail. Z. mobilis glyceraldehyde-phosphate dehydrogenase was found to be similar in most respects to the enzyme from other sources, except for having a slightly larger subunit size. Phosphoglycerate kinase has properties typical for this enzyme; however, it did not show the sulphate activation effects characteristic of this enzyme from most other sources. Phosphoglycerate mutase is a dimer, partially independent of 2,3-bisphosphoglycerate, and has a high specific activity. Enolase was found to be octameric; otherwise its properties were very similar to those of the yeast enzyme. Pyruvate kinase is unusual in being dimeric, and not requiring K+ for activity. It is not allosterically activated by sugar phosphates, having a high activity in the absence of any effectors. Some quantitative differences in the relative amounts of these enzymes, compared with eukaryotic species, are ascribed to the fact that Z. mobilis utilizes the Entner-Doudoroff pathway rather than the more common Embden-Meyerhoff glycolytic route.
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PMID:Isolation and properties of the glycolytic enzymes from Zymomonas mobilis. The five enzymes from glyceraldehyde-3-phosphate dehydrogenase through to pyruvate kinase. 302 43

Previous results from this laboratory have shown that very low chronic doses of gamma radiation can stimulate proliferation of the Cyanobacterium Synechococcus lividus. This modification of cell proliferation occurred during the first doubling. In this paper, we have compared the metabolism of cells cultivated in a normal environment or under chronic irradiation. Incubation of the cells in a new medium induced a high superoxide dismutase (EC 1.15.1.1, SOD) activity at the 18th hour and a degradation of phycocyanin, thus demonstrating that cells were submitted to a photooxidative stress. This increase in superoxide dismutase activity was followed by concomitant peaks of glutathione reductase (EC 1.6.4.2, GR) and glucose-6-phosphate dehydrogenase (EC 1.1.1.49, G6P-DH) at the 24th hour. Irradiated cultures at a dose of 53.5 mGray/year show an earlier and higher peak of SOD, GR, and G6P-DH. In a second stage, cultures showed an earlier onset of photosynthesis under irradiation, as evidenced by an increase in pigment content and an enhancement of glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.13, GAP-DH). These results show that the radiostimulation is related to the activation of enzymes protecting against peroxides that were induced under oxidative circumstances and to the activation of a glucose catabolism via the oxidative pentose phosphate pathway.
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PMID:Influence of very low doses of ionizing radiation on Synechococcus lividus metabolism during the initial growth phase. 308 88

NADP-dependent nonphosphorylating D-glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.9) from spinach leaves has been purified to apparent electrophoretic homogeneity by ammonium sulfate fractionation, molecular sieving on Sephadex G-200, DEAE-cellulose, and 2',5'-ADP-Sepharose affinity chromatography. The purified enzyme exhibited a specific activity of 15 mumol (mg protein)-1 min-1 and was characterized as a homotetramer with a native molecular weight of 195,000. Preincubation of the purified enzyme with NADP+ resulted in an almost twofold increase in enzymatic activity. The rate of activation was slower than the rate of catalysis, indicating that the enzyme has hysteretic properties. This behavior results in a lag phase during activity measurement of the enzyme preincubated without NADP+. Substrate interaction and product inhibition studies suggest a rapid equilibrium random BiBi mechanism for the reaction. Thiol modifying reagents, iodoacetamide and diamide, completely inactivated the purified enzyme. Inactivation by iodoacetamide exhibited pseudo-first-order kinetics with a rate constant of 0.17 min-1. D-Glyceraldehyde 3-phosphate effectively protected the enzyme against inactivation by thiol reagents, suggesting that modification occurred at or near the substrate-binding site. Complete inactivation of the dehydrogenase was correlated with incorporation of 8 mol [1-14C]iodoacetamide/mol enzyme. Total protection afforded by D-glyceraldehyde 3-phosphate against enzyme inactivation by iodoacetamide was correlated with a protection of 4 mol reactive residues/mol enzyme. On the basis of these results it is suggested that one sulfhydryl group per enzyme subunit is essential for catalysis in spinach leaf nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase. A kinetic and molecular mechanism for the reaction is proposed.
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PMID:Purification and kinetic and structural properties of spinach leaf NADP-dependent nonphosphorylating glyceraldehyde-3-phosphate dehydrogenase. 334 66

In the presence of Mg2+, the formation of actin filaments is hindered by glyceraldehyde-3-phosphate dehydrogenase. This effect, which increases with the square of Mg2+ concentration, is counteracted by 0.15 M KCl. Thus KCl, at concentrations found in the intracellular compartment, appears to be strictly required for the correct formation of actin filaments in all tissues in which the glyceraldehyde-phosphate dehydrogenase concentration is high.
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PMID:On an Mg2+-dependent interaction of actin with glyceraldehyde-phosphate dehydrogenase. The fundamental role of KCl in the organization of F-actin. 362 77

A steady-state kinetic analysis of the coupled reactions catalysed by the three-enzyme system, aldolase, glyceraldehyde-3-phosphate dehydrogenase and triosephosphate isomerase, was performed. The kinetic parameters of the progress curves of end-product formation calculated for noninteracting enzymes were compared with those measured in the two-enzyme and three-enzyme systems. Changes in the fluorescence anisotropy of labelled dehydrogenase upon addition of aldolase and/or isomerase were also measured. Glyceraldehyde-3-phosphate oxidation catalysed by glyceraldehyde-3-phosphate dehydrogenase in the presence of isomerase (which ensures rapid equilibration of the triosephosphates) follows single first-order kinetics. The rate constant depends simply on the concentration of the dehydrogenase, indicating no kinetically significant isomerase-dehydrogenase interaction. Fluorescence anisotropy measurements also fail to reveal complex formation between the two enzymes. The steady-state velocity of 3-phosphoglycerate formation from fructose 1, 6-bisphosphate in the reactions catalysed by aldolase and dehydrogenase is not increased twofold on addition of the isomerase, even though a 1:2 stoichiometry of fructose 1,6-bisphosphate/glyceraldehyde 3-phosphate is expected. In fact, by increasing the concentration of the isomerase, the steady-state velocity actually decreases. This effect of the isomerase may be a kinetic consequence of an aldolase-isomerase interaction, which results in a decrease of aldolase activity. Furthermore, the fluorescence anisotropy of labelled dehydrogenase, measured at different aldolase concentrations, is significantly lower when the sample contains isomerase. The decrease in the steady-state velocity of the consecutive reactions caused by the elevation of isomerase concentration could be negated by increasing the dehydrogenase concentrations in the three-enzyme system. All of these observations fit the assumption that the amount of aldolase-dehydrogenase complex is reduced due to competition of isomerase with dehydrogenase. The alternate binding of dehydrogenase and isomerase to aldolase may regulate the flux rate of glycolysis.
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PMID:Dynamic interactions of enzymes involved in triosephosphate metabolism. 378 Jul 25


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