Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: EC:4.1.2.13 (aldolase)
 3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

1. The regulation of glycolysis and pyruvate oxidation under varying conditions of ATP and oxygen consumption was studied in isolated perfused rat hearts. Potassium-induced arrest was employed to inhibit the ATP consumption of the heart. 2. Under the experimental conditions, the beating heart used solely glucose as the oxidisable substrate. The glycolytic flux through the aldolase step decreased in pace with the decreasing oxygen consumption during the potassium-induced arrest of the heart. The decrease in glucose oxidation was larger than the inhibition of the oxygen consumption, suggesting that the arrested heart switches to fatty acid oxidation. The time course and percentage changes of the inhibition of pyruvate oxidation and the decrease in the amount of the active form of pyruvate dehydrogenase suggest that the amount of active pyruvate dehydrogenase is the main regulator of pyruvate oxidation in the perfused heart. 3. To test the relative significance of the possible mechanisms regulating covalent interconversions of pyruvate dehydrogenase, the following parameters were measured in response to the potassium-induced cardiac arrest: concentrations of pyruvate, acetyl-CoA, CoA-SH, citrate, alpha-oxoglutarate, ATP, ADP, AMP, creatine, creatine phosphate and inorganic phosphate and the mitochondrial NADH/NAD+ ratio. In cardiac tissue the adenylate system is not a good indicator of the energy state of the mitochondrion, even when the concentrations of AMP and free cytosolic ADP are calculated from the adenylate kinase and creatine kinase equilibria. Only creatine phosphate and inorganic phosphate undergo significant changes, but evidence of the participation of the latter compounds in the regulation of the pyruvate dehydrogenase interconversions is lacking. The potassium-induced arrest of the heart resulted in a decrease in pyruvate, a slight increase in acetyl-CoA, a large increase in the concentration of citrate and an increase in the mitochondrial NADH/NAD+. The results can be interpreted as showing that in the heart, the pyruvate dehydrogenase interconversions are mainly regulated by the pyruvate concentration and the mitochondrial redox state. Concentrations of all the regulators tested shifted to directions which one would expect to result in a decrease in the amount of active pyruvate dehydrogenase, but the changes were quite small. Therefore, the energy-linked regulation of pyruvate dehydrogenase in intact tissue is possibly mediated by the equilibrium relations between the cellular redox state and the phosphorylation potential recently confirmed in cardiac tissue.
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PMID:Energy-linked regulation of glucose and pyruvate oxidation in isolated perfused rat heart. Role of pyruvate dehydrogenase. 18 44

Two new symmetrical bis(imido esters), N,N'-bis(2-carboximidoethyl)tartarimide dimethyl ester dihydrochloride and N,N'-bis(2-carboximidomethyl)tartarimide dimethyl ester dihydrochloride, have been synthesized. Tests with the tetrameric enzyme, fructose diphosphate aldolase, show that these reagents closely resemble dimethyl suberimidate in their ability to cross-link protein subunits. However, identification of the cross-linked species, separated by sodium dodecyl sulfate polyacrylamide gel electrophoresis, is greatly facilitated since the cross-links can be broken by a simple treatment with sodium periodate. The periodate cleavage step can be introduced between the two dimensions of a diagonal gel electrophoretic separation, the contributors to a cross-linked species then moving off the diagonal formed by uncross-linked proteins and reverting to the positions in the gel that correspond with their regenerated monomeric form. When the pyruvate dehydrogenase multienzyme complex of Escherichia coli was treated with dimethyl suberimidate or N,N'-bis(2-carboximidoethyl)tartarimide dimethyl ester dihydrochloride, cross-links rapidly formed between the subunits of the transacetylase and lipoamide dehydrogenase components. On the other hand, cross-links failed to form between the subunits of the decarboxylase component themselves, or between the decarboxylase and the other two types of subunit in the complex. Cross-linking experiments with the isolated lipoamide dehydrogenase were compatible with the accepted dimeric structure of this enzyme is free solution, whereas the isolated pyruvate decarboxylase component also failed to cross-link when treated with dimethyl suberimidate in free solution. The cross-linking experiments with the intact multienzyme complex provide evidence for the existence of the lipoamide dehydrogenase dimer in the assembled enzyme and show the need to interpret such experiments with care since, from other evidence, the pyruvate decarboxylase component is known to be bound to the transacetylase "core" of the complex.
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PMID:Use of dimethyl suberimidate and novel periodate-cleavable bis(imido esters) to study the quaternary structure of the pyruvate dehydrogenase multienzyme complex of Escherichia coli. 77 24

The hydrophobic nature of proteins is characterized by a degree of 2-p-toluidinonaphthalene-6-sulphonate (TNS) affinity to them and is pronounced quantitatively in the semi-saturated (C1/2) concentrations. This index correlates directly with the position of TNS emission maximum after the binding with proteins and reversely with the yield of fluorescence. The preparations of phosphofructokinase, lactate dehydrogenase, xantinoxidase, glyceratekinase, lysozyme, RNase during the long (1-2 h) contact with TNS change the values C1/2, that evidences for interaction with the hydrophobic indicator of new structures of protein molecule or for a change in the nature of its linkage itself. An attempt is made to characterize the accessible for TNS hydrophobic nature of individual proteins by a coefficient of molar hydrophobic nature which unites three mentioned characteristics. Serum albumin, insulin, glucogon, alpha chemotrypsin, DNase are most hydrophobic, pyruvate kinase, aldolase, urease, RNase--least hydrophobic, Glycerate kinase, pyruvate decarboxylase, phosphofructokinase, lactate dehydrogenase, alcohol dehydrogenase, xanthinoxidase, trypsin, lysozyme are in intermediate position.
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PMID:[Comparative characteristics of hydrophobic nature of certain proteins by their interaction with 2-p-toluidinonaphthalene-6-sulfonates]. 120 4

The activity of the glycolysis enzymes, i.e. aldolase and pyruvate decarboxylase and the enzymes of the pentose cycle, i.e. transketolase were investigated in the process of cultivation of an active strain and inactive mutant of Act. rimosus under conditions favourable for oxytetracycline biosynthesis on starch medium and under unfavourable conditions on glucose medium. It was shown that the aldolase and transketolase activity in the inactive mutant was higher on the starch medium as compared to the active strain, while the activity of pyruvate dekarboxylase was lower. The above difference between the both strains was preserved on the glucose medium and the activity of aldolase and transketolase in both strains increased, while the activity of pyruvate dekarboxylase remained at the same level.
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PMID:[Study of certain carbohydrate metabolism enzymes in an active oxytetracycline producer strain and in an inactive mutant in relation to antibiotic biosynthesis]. 127 61

Enzymes that mediate carbanion chemistry must protect their reactants from solvent and undesirable electrophiles, such as molecular oxygen. A number of enzymes that utilize carbanionic intermediates were surveyed for O2-consuming side reactions. Several of these enzymes, acetolactate synthase, pyruvate decarboxylase, class II aldolase, and glutamate decarboxylase, catalyze previously undetected oxygen-consuming reactions, while others such as class I aldolase, [(phosphoribosyl)amino]imidazole carboxylase, 6-phosphogluconate dehydrogenase, isocitrate dehydrogenase, and triosephosphate isomerase do not. Prior to this work, only ribulosebisphosphate carboxylase was known to catalyze an oxygenase side reaction. These new example indicate that while O2-consuming side reactions are a more general feature of enzyme-mediated carbanion chemistry than has been previously appreciated, they are not necessarily an inevitable consequence of this chemistry. Expression of an oxygenase activity not only depends on the accessibility of the carbanionic intermediate to molecular oxygen but also may depend on the ability of the enzyme to stabilize the initially formed peroxide anion either through protonation with an appropriate enzymic group or through metal coordination.
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PMID:Oxygenase side reactions of acetolactate synthase and other carbanion-forming enzymes. 186 63

Anaerobiosis results in the selective synthesis of a particular set of polypeptides in the maize root including the two alcohol dehydrogenases (Sachs, M. M., Freeling, M., and Okimoto, R. (1980) Cell 20, 761-768), pyruvate decarboxylase (Wignarajah, K., and Greenway, H. (1976) New Phytol. 77, 575-584; Laszlo, A., and St. Lawrence, P. (1983) Mol. Gen. Genet. 192, 110-117), glucose phosphate isomerase (Kelley, P. M., and Freeling, M. (1984) J. Biol. Chem. 259, 673-677) and aldolase (Kelley, P. M., and Freeling, M. (1984) J. Biol. Chem. 259, 14180-14183). This report describes the identification and characterization of cDNA clones to five different mRNA species induced upon anaerobic shock. Immunoprecipitation of hybrid-selected translation polypeptides has determined the identity of the cDNA clone for fructose-1,6-diphosphate aldolase mRNA. Quantitative hybridization analysis of anaerobic mRNAs using the cDNA clones has shown that there is not a simultaneous accumulation of anaerobic mRNAs. Upon reintroduction of air, the anaerobic mRNAs disappear rapidly and at approximately the same rate. A translocation line that generates progeny that contain 1, 2, and 3 doses of the long arm of chromosome one (1L) allowed us to test for clustering of the anaerobic genes; two of the anaerobic genes tested do not reside with Adh 1 and Phi 1 on the long arm of chromosome 1.
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PMID:Coordinate induction of alcohol dehydrogenase 1, aldolase, and other anaerobic RNAs in maize. 258 Aug 29

The proteins of soybean roots undergoing anaerobiosis can be grouped into three classes. Class 1 proteins are induced severalfold and at least 28 of these were identified by in vivo labeling. These proteins include the enzymes alcohol dehydrogenase (ADH), fructose aldolase, pyruvate decarboxylase, phosphoglucomutase, and lactate dehydrogenase. Class 2 proteins include such enzymes as glucose phosphate isomerase, sucrase, and malate dehydrogenase; their specific activity remains constant in aerobiosis or anaerobiosis. The third class of proteins includes those enzymes such as peroxidase whose activity decreases more than 90% after just 1 day in anaerobiosis. Immunoblotting coupled with two-dimensional chromatography of in vitro translated plant extracts demonstrated that ADH level during anaerobiosis is controlled by its mRNA concentration. Little or no mRNA for ADH was detected in aerobically grown roots. This suggests that the increased level of ADH activity is due to de novo synthesis of the mRNA rather than activation of a sequestered mRNA or superactivation of the protein.
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PMID:Gene regulation during anaerobiosis in soya roots. 262 97

1. Enzymic evidence supporting the operation of the Entner-Doudoroff pathway in the anaerobic conversion of glucose into ethanol and carbon dioxide by Zymomonas mobilis is presented. 2. Cell extracts catalysed the formation of equimolar amounts of pyruvate and glyceraldehyde 3-phosphate from 6-phosphogluconate. Evidence that 3-deoxy-2-oxo-6-phosphogluconate is an intermediate in this conversion was obtained. 3. Cell extracts of the organism contained the following enzymes: glucose 6-phosphate dehydrogenase (active with NAD and NADP), ethanol dehydrogenase (active with NAD), glyceraldehyde 3-phosphate dehydrogenase (active with NAD), hexokinase, gluconokinase, glucose dehydrogenase and pyruvate decarboxylase. Extracts also catalysed the overall conversion of glycerate 3-phosphate into pyruvate in the presence of ADP. 4. Gluconate dehydrogenase, fructose 1,6-diphosphate aldolase and NAD-NADP transhydrogenase were not detected. 5. It is suggested that NAD is the physiological electron carrier in the balanced oxidation-reduction involved in ethanol formation.
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PMID:The route of ethanol formation in Zymomonas mobilis. 428 42

The regional enzyme activities of glucose metabolism in the rat brain were investigated. Hexokinase (EC 2.7.1.1) and pyruvate dehydrogenase (EC 1.2.4.1), key enzymes for glucose metabolism, showed no changes in activity in all the regions studied of the aging brain as compared with the adult brain. However, the activity of D-3-hydroxybutyrate dehydrogenase (EC 1.1.1.30) is low throughout the adult brain and, in contrast with hexokinase and pyruvate dehydrogenase, its activity decreases significantly during aging. Other enzymes that showed significant decreases during aging are aldolase (EC 4.1.2.13), lactate dehydrogenase (EC 1.1.1.27), citrate synthase (EC 4.1.3.7), and NAD+-linked isocitrate dehydrogenase (EC 1.1.1.41). The catabolic enzyme in cholinergic metabolism, acetylcholinesterase (EC 3.1.1.7), selected as an example of a non-energy-metabolising enzyme, also showed significant decreases in all regions of the brain in aging, although its highest activity remained in the striatum. These results are discussed with respect to the energy metabolism in various brain regions and their status with aging.
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PMID:Energy-metabolizing enzymes in brain regions of adult and aging rats. 646 Aug 51

Thermoanaerobium brockii was shown to catabolize glucose via the Embden-Meyerhof-Parnas pathway into ethanol, acetic acid, H(2)-CO(2), and lactic acid. Radioactive tracer studies, employing specifically labeled [(14)C]glucose, demonstrated significant fermentation of (14)CO(2) from C-3 and C-4 of the substrate exclusively. All extracts contained sufficient levels of activity (expressed in micromoles per minute per milligram of protein at 40 degrees C) to assign a catabolic role for the following enzymes: glucokinase, 0.40; fructose-1,6-diphosphate aldolase, 0.23; glyceraldehyde-3-phosphate dehydrogenase, 1.73; pyruvate kinase, 0.36; lactate dehydrogenase (fructose-1,6-diphosphate activated), 0.55; pyruvate dehydrogenase (coenzyme A acetylating), 0.53; hydrogenase, 3.3; phosphotransacetylase, 0.55; acetaldehyde dehydrogenase (coenzyme A acetylating), 0.15; ethanol dehydrogenase, 1.57; and acetate kinase, 1.50. All pyridine nucleotide-linked oxidoreductases examined were specific for nicotinamide adenine dinucleotide, except ethanol dehydrogenase which displayed both nicotinamide adenine dinucleotide- and nicotinamide adenine dinucleotide phosphate-linked activities. Fermentation product balances and cell growth yields supported the glucose catabolic pathway described. Representative balanced end product yields (in moles per mole of glucose fermented) were: ethanol, 0.94; l-lactate, 0.84; acetate, 0.20; CO(2), 1.31; and H(2), 0.50. Growth yields of 16.4 g of cells per mole of glucose were demonstrated. Both growth and end product yields varied significantly in accordance with the specific medium composition and incubation time.
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PMID:Glucose fermentation pathway of Thermoanaerobium brockii. 676 5


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