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:4.1.2.13 (aldolase)
3,461 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Anaerobic glycolysis in Saccharomyces cerevisiae has been studied by 13C NMR at 90.5 MHz. [1-13c]Glucose and [6-13C]glucose were fed to suspensions of yeast cells. Time courses for concentration changes of the starting material, of courses for concentration changes of the starting material, of the intermediate fructose 1,6-bisphosphate (Fru-P2), and of the end products, ethanol and glycerol, have been followed with 1-min time resolution. The glucose uptake was well fitted by a Michaelis-Menten model, assuming competition of alpha- and beta-glucose for the same site. The Km for the uptake was found to be 10 mM for beta-glucose and 5 mM for alpha-glucose. The concentration of Fru-P2 showed an initial oscillation before it reached a co,stant level. The 13C label, introduced only as [-13C]- or [6-13C]glucose, was observed in Fru-P2 in both the C1 and C6 positions, simultaneously. From the relative intensities of the C1 Fru-P2 and C6 Fru-P2 peaks in the presence of [1-13C]- and [6-13C]glucose, in vivo kinetic information was obtained about the aldolase-triosephosphate isomerase triangle. We found that under the conditions of these experiments the ratios of backward to forward velocities through aldolase and triosephosphate isomerase were 0.9 +/- 0.1 and 0.8 +/- 1, respectively, indicating they were close to equilibrium.
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PMID:13C nuclear magnetic resonance studies of anaerobic glycolysis in suspensions of yeast cells. 4 10

Cell-free extracts of D-fructose grown cells of marine species of Alcaligenes as well as Pseudomonas marina contained an activity which catalyzed a P-enolpyruvate-dependent phosphorylation of D-fructose in the 1-position as well as activities of the following enzymes: 1-P-fructokinase, fructose-1,6-P2 aldolase, PPi-dependent 6-P-fructokinase, fructokinase, glucokinase, P-hexose isomerase, glucose-6-P dehydrogenase, 6-P-gluconate dehydrase, and 2-keto-3-deoxy-6-P-gluconate aldolase. The presence of these enzyme activites would allow D-fructose to be degraded by the Embden-Meyerhof pathway and/or the Entner-Doudoroff pathway. In cell-free extracts of D-glucose grown cells, the activity catalyzing a P-enolpyruvate-dependent phosphorylation of D-fructose as well as 1-P-fructokinase activity were reduced or absent while the remaining enzymes were present at levels similar to those found in D-fructose grown cells. Radiolabeling experiments suggested that both D-fructose and D-glucose were utilized primarily via the Entner-Doudoroff pathway. Alteromonas communis, a marine species lacking 1-P-fructokinase and the PPi-dependent 6-P-fructokinase, contained all the enzyme activites necessary for the catabolism of D-fructose and D-glucose by the Entner-Doudoroff pathway; the involvement of this pathway was also consitent with the results of the radiolabeling experiments.
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PMID:Pathways of D-fructose and D-glucose catabolism in marine species of Alcaligenes, Pseudomonas marina, and Alteromonas communis. 13 58

Caulobacter crescentus wild-type strain CB13 is unable to utilize galactose as the sole carbon source unless derivatives of cyclic AMP are present. Spontaneous mutants have been isolated which are able to grow on galactose in the absence of exogenous cyclic nucleotides. These mutants and the wild-type strain were used to determine the pathway of galactose catabolism in this organism. It is shown here that C. crescentus catabolizes galactose by the Entner-Duodoroff pathway. Galactose is initially converted to galactonate by galactose dehydrogenase and then 2-keto-3-deoxy-6-phosphogalactonate aldolase catalyzes the hydrolysis of 2-keto-3-deoxy-6-phosphogalactonic acid to yield triose phosphate and pyruvate. Two enzymes of galactose catabolism, galactose dehydrogenase and 2-keto-3-deoxy-6-phosphogalactonate aldolase, were shown to be inducible and independently regulated. Furthermore, galactose uptake was observed to be regulated independently of the galactose catabolic enzymes.
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PMID:Galactose catabolism in Caulobacter crescentus. 21 Jan 53

After a brief exposition to glucose, Thiobacillus acidophilus was isolated from a culture of iron-grown T. ferrooxidans. Physicochemical analysis of its DNA showed a G+C content of 62.9-63.2%. The new isolate grows best at 25-30 degrees C and at pH 3.0. Growth is possible between pH 1.5 and 6.0. Thiobacillus acidophilus is apparently strictly aerobic. Ammonium salts are the only suitable source of nitrogen. The bacterium is a facultative autotroph. In addition to elemental sulfur, it obtains energy from organic compounds such as D-glucose, D-galactose, D-fructose, D-mannitol, D-xylose, D-ribose, D-arabinose, L-arabinose, sucrose, sodium citrate, malic acid,dl-aspartic acid, and dl-glutamic acid. Thiobacillus acidophilus possesses the key enzymes of the tricarboxylic acid (TCA) cycle including NAD-and NADP-linked isocitric dehydrogenase and alpha-ketoglutarate dehydrogenase, and the key enzymes of the hexose monophosphate pathway (glucose-6-phosphate and 6-phosphogluconate dehydrogenase, and fructose 1,6-diphosphate aldolase). NADH oxidase has been found in particulate fraction of extracts. Rhodanese and thiosulfate oxidase have also been detected.
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PMID:Thiobacillus acidophilus sp. nov.; isolation and some physiological characteristics. 23 84

D-glycero-L-galacto-Octulose and L-glycero-L-galacto-octulose accumulated when leaves of Kenland red clover (Trifolium pratense) were allowed to imbibe solution of D-gulose or D-xylose and L-mannose or L-arabinose, respectively. The octuloses were isolated and identified by paper chromatography and by oxidative degradations to the corresponding lower sugars. Assignments of the D and L configuration were made on the basis of optical rotation. It is suggested that formation of the octuloses from the hexoses and pentoses is mediated through transketolase and aldolase or transaldolase catalysis, respectively.
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PMID:Biosynthesis of D- and L-glycero-L-galacto-octulose from pentoses and hexoses. 111 59

Chemostat cultures of Erwinia amylovora 595, grown in mineral salts-nicotinic acid medium at 30 degrees C, and limited by D-glucose concentrations in the presence of dissolved oxygen tensions (D.O.T.) greater than about 6mm Hg, became limited by oxygen availability below about 4 mm Hg. This latter limitation was accompanied by a marked increase in acid production as the D.O.T. was depressed. The transition between D-glucose- and oxygen-limitation was also characterized by a maximum in succinate oxidase activity, and a minimum in the in situ respiration. D-Glyceraldehyde-3-phosphate dehydrogenase and D-fructose-1, 6-diphosphate aldolase showed small reductions in specific activity in the region 4-6 mm Hg D.O.T., but further reduction to 2 mm Hg resulted in a marked increase in the specific activity of aldolase. Malate dehydrogenase followed the converse trend, and attained very low activity levels when the D.O.T. decreased beyond the lower limits of detection. The in situ respiration was maximal at 2 mm Hg D.O.T., while potential respiration values were minimal at 2 mm Hg, and maximal at about 8 mm Hg D.O.T. The insitu respiration rate was proportional to dilution rate (D), in presence of excess oxygen, up to 0.18 h-1, after which a marked diminution occurred and continued until the wash-out rate was attained. Succinate oxidase activity decreased with increase in dilution rate, but remained constant above D equals 0.18 h-1. Malate dehydrogenase showed a persistent decline with increase in dilution rate, while D-glyceraldehyde-3-phosphate activity increased somehwat at higher dilution rates. The data are interpreted in terms of two transition points, at 6 and 2 mm Hg D.O.T., and of a change from respiratory to fermentative metabolism at low D.O.T., and at high dilution rates.
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PMID:Variation in the activity levels of selected enzymes of Erwinia amylovora 595 in response to changes in dissolved oxygen tension and growth rate of D-glucose-limited chemostat cultures. 111 45

DNA cloned into Escherichia coli K-12 from a serotype c strain of Streptococcus mutans encodes three enzyme activities for galactose utilization via the tagatose 6-phosphate pathway: galactose 6-phosphate isomerase, tagatose 6-phosphate kinase, and tagatose-1,6-bisphosphate aldolase. The genes coding for the tagatose 6-phosphate pathway were located on a 3.28-kb HindIII DNA fragment. Analysis of the tagatose proteins expressed by recombinant plasmids in minicells was used to determine the sizes of the various gene products. Mutagenesis of these plasmids with transposon Tn5 was used to determine the order of the tagatose genes. Tagatose 6-phosphate isomerase appears to be composed of 14- and 19-kDa subunits. The sizes of the kinase and aldolase were found to be 34 and 36 kDa, respectively. These values correspond to those reported previously for the tagatose pathway enzymes in Staphylococcus aureus and Lactococcus lactis.
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PMID:Streptococcus mutans serotype c tagatose 6-phosphate pathway gene cluster. 132 53

Aldolase and triose phosphate isomerase both display strict specificity towards the enantiomers of [1-3H]glycerone 3-phosphate. The enantiomer generated from D-[1-3H]glyceraldehyde 3-phosphate produces 3HOH in the aldolase reaction, whilst the other enantiomer generated from D-[3-3H]fructose 1,6-bisphosphate is solely detritiated in the reaction catalyzed by triose phosphate isomerase. Advantage was taken of such a specificity to assess, in human erythrocytes exposed to either D-[3-3H]glucose or D-[3,4-3H]glucose, the extent of D-glyceraldehyde 3-phosphate sequential conversion to glycerone 3-phosphate and D-fructose 1,6-bisphosphate, relative to net glycolytic flux. At 37 degrees C and in the presence of 5.6 mM D-glucose, only 55% of the metabolites of D-[4-3H]glucose underwent detritiation in the reactions catalyzed by triose phosphate isomerase and aldolase. Such a percentage was further decreased at low temperature (8 degrees C) or lower concentrations of D-glucose (0.2 and 1.0 mM). However, when the erythrocytes were exposed to menadione, the increase in 3HOH production from either D-[3-3H]glucose or D-[3,4-3H]glucose indicated that the majority of the 3H atoms initially located on the C4 of D-glucose were recovered as 3HOH upon circulation through the pentose phosphate pathway. These findings suggest that, under physiological conditions, a large fraction of D-glyceraldehyde 3-phosphate generated from exogenous D-glucose may undergo enzyme-to-enzyme channelling in the glycolytic pathway.
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PMID:Interconversion of D-fructose 1,6-bisphosphate and triose phosphates in human erythrocytes. 159 48

The nucleotide and deduced amino acid sequences of the lacA and lacB genes of the Staphylococcus aureus lactose operon (lacABCDFEG) are presented. The primary translation products are polypeptides of 142 (Mr = 15,425) and 171 (Mr = 18,953) amino acids, respectively. The lacABCD loci were shown to encode enzymes of the tagatose 6-phosphate pathway through both in vitro studies and complementation analysis in Escherichia coli. A serum aldolase assay, modified to allow detection of the tagatose 6-phosphate pathway enzymes utilizing galactose 6-phosphate or fructose phosphate analogs as substrate, is described. Expression of both lacA and lacB was required for galactose 6-phosphate isomerase activity. LacC (34 kDa) demonstrated tagatose 6-phosphate kinase activity and was found to share significant homology with LacC from Lactococcus lactis and with both the minor 6-phosphofructokinase (PfkB) and 1-phosphofructokinase (FruK) from E. coli. Detection of tagatose 1,6-bisphosphate aldolase activity was dependent on expression of the 36-kDa protein specified by lacD. The LacD protein is highly homologous with LacD of L. lactis. Thus, the lacABCD genes comprise the tagatose 6-phosphate pathway and are cotranscribed with genes lacFEG, which specify proteins for transport and cleavage of lactose in S. aureus.
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PMID:Lactose metabolism by Staphylococcus aureus: characterization of lacABCD, the structural genes of the tagatose 6-phosphate pathway. 165 95

An inborn deficiency in the ability of aldolase B to split fructose 1-phosphate is found in humans with hereditary fructose intolerance (HFI). A stable isotope procedure to elucidate the mechanism of conversion of fructose to glucose in normal children and in HFI children has been developed. A constant infusion of D-[U-13C]fructose was given nasogastrically to control and to HFI children. Hepatic fructose conversion to glucose was estimated by examination of 13C NMR spectra of plasma glucose. The conversion parameters in the control and HFI children were estimated on the basis of doublet/singlet values of the plasma beta-glucose C-1 splitting pattern as a function of the rate of fructose infusion (0.26-0.5 mg/kg per min). Significantly lower values (approximately 3-fold) for fructose conversion to glucose were obtained for the HFI patients as compared to the controls. A quantitative determination of the metabolic pathways of fructose conversion to glucose was derived from 13C NMR measurement of plasma [13C]glucose isotopomer populations. The finding of isotopomer populations of three adjacent 13C atoms at glucose C-4 (13C3-13C4-13C5) suggests that there is a direct pathway from fructose, by-passing fructose-1-phosphate aldolase, to fructose 1,6-bisphosphate. The metabolism of fructose by fructose-1-phosphate aldolase activity accounts for only approximately 50% of the total amount of hepatic fructose conversion to glucose. It is suggested that phosphorylation of fructose 1-phosphate to fructose 1,6-bisphosphate by 1-phosphofructokinase occurs in human liver (and intestine) when fructose is administered nasogastrically; 47% and 27% of the total fructose conversion to glucose in controls and in HFI children, respectively, takes place by way of this pathway. In view of the marked decline by 67% in synthesis of glucose from fructose in HFI subjects found in this study, the extent of [13C]glucose formation from a "trace" amount (approximately 20 mg/kg) of [U-13C]fructose infused into the patient can be used as a safe and noninvasive diagnostic test for inherent faulty fructose metabolism.
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PMID:Determination of fructose metabolic pathways in normal and fructose-intolerant children: a 13C NMR study using [U-13C]fructose. 237 Dec 80


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