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)

We have previously reported that the chitin catabolic cascade in Vibrio furnissii involves multiple signal transducing systems, and that mono- and disaccharide chemoreceptors/transporters are essential components of some of these systems. This and the accompanying papers (Bouma, C. L., and Roseman, S. (1996) J. Biol. Chem 271, 33457-33467; Keyhani, N. O., Wang, L.-X., Lee, Y. C., and Roseman, S. (1996) J. Biol. Chem. 271, 33409-33413) describe some of the sugar transporters. A 13-kilobase pair fragment of V. furnissii DNA was found to impart a Glc+, Man+ phenotype to Escherichia coli ptsG ptsM mutants, and encodes the mannose transporter, ptsM, of the phosphoenolpyruvate:glycose phosphotransferase system. Unlike the E. coli mannose permease, V. furnissii IIMan is inactive with GlcNAc and Fru, and is encoded by four genes rather than three. The gene order is manXYZW, where the product of manY corresponds to IIPMan, manZ to the mannose receptor IIBMan, and manX and manW to the single E. coli gene, manX (which encodes IIIMan, viz. IIAMan). Thus, in V. furnissii, the E. coli manX equivalent comprises two genes, which are separated in the genome by two other genes of the ptsM complex. Two additional open reading frames were detected in the V. furnissii DNA fragment. One encodes a GlcNAc-6-P deacetylase, and the other is similar to aldolase.
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PMID:Sugar transport by the marine chitinolytic bacterium Vibrio furnissii. Molecular cloning and analysis of the mannose/glucose permease. 896 10

The generation of 13C-labeled D-glucose isotopomers by rat hepatocytes incubated for 30 or 120 min in the presence of 10 mM [3-(13)C]pyruvate was assessed by 13C NMR. The amount of C1-labeled D-glucose exceeded that of C2-labeled hexose, which was itself higher than that of C3-labeled D-glucose. A comparable hierarchy was observed in the C6-C5-C4 moiety of the hexose. The latter moiety of D-glucose was more efficiently labeled, however, than the C3-C2-C1 moiety. This finding is similar to that both previously reported and again observed in the present study when hepatocytes were exposed to [2(-13)C]pyruvate. These converging observations thus support the concept of enzyme-to-enzyme channeling of D-glyceraldehyde 3-phosphate between glyceraldehyde-3-phosphate dehydrogenase and phospho-fructoaldolase.
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PMID:Asymmetrical labeling of D-glucose generated from [3(-13)C]pyruvate in rat hepatocytes. 925 88

The enzymatic synthesis of 2-keto-3-deoxy-D-glycero-D-galacto-nonopyranulosonic acid (KDN) starting from D-mannose and pyruvic acid using Neu5Ac-aldolase has been scaled up. A repetitive batch ultrafiltration bioreactor was used for the KDN synthesis on 100 g scale with a conversion of up to 85%. Furthermore, a 440 mL pilot-scale enzyme membrane reactor (EMR) was performed for the continuous production of KDN. Conversion of mannose was 75% at a space--time yield of 375 g/(L d). KDN was advanteageously isolated by crystallization with an overall yield of 75%.
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PMID:Enzymatic large-scale production of 2-keto-3-deoxy-D-glycero-D-galacto-nonopyranulosonic acid in enzyme membrane reactors. 941 39

5,9-Diacetamido-2,6-anhydro-O-4-carbamoylmethyl-3,5,9-trideo xy-D-glycero- D-galacto-non-2-enonic acid (1) was synthesized via a key intemediate 2 through the Neu5Ac aldolase [E.C.4.1.3.3]-catalyzed aldol reaction of 2-acetamido-2,6-dideoxy-6-azido-D-glucose with sodium pyruvate operating under alkaline conditions (pH 10.5) in order to accelerate epimerization C-2 of N-acetyl-D-glucosamine (D-GlcNAc) derivatives. Compound 1 showed inhibitory activity against sialidase.
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PMID:Chemoenzymatic synthesis of an N-acetylneuraminic acid analogue having a carbamoylmethyl group at C-4 as an inhibitor of sialidase from influenza virus. 986 96

Various D-fructose analogues modified at C-1 or C-6 positions were synthesized from D-glucose by taking advantage of the Amadori rearrangement or using the aldol condensation between dihydroxyacetone phosphate and appropriate aldehyde catalyzed by fructose 1,6-diphosphate aldolase from rabbit muscle. The affinities of the analogues for the glucose transporter expressed in the mammalian form of Trypanosoma brucei were determined by inhibition of radiolabelled 2-deoxy-D-glucose (2-DOG) transport using zero-trans kinetic analysis. Interestingly, the analogues bearing an aromatic group (i.e. a fluorescence marker) at C-1 or C-6 positions present comparable apparent affinities to D-fructose for the transporter. This result could find applications for hexose transport studies and also provides criteria for the design of glucose import inhibitors.
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PMID:Chemical and enzymatic synthesis of fructose analogues as probes for import studies by the hexose transporter in parasites. 1081 60

Aspergillus niger could utilize D-galactose as sole source of carbon. Cell-free extracts of D-galactose-grown mycelia were able to catalyze the oxidation of D-galactose to D-galactonic acid-gamma-lactone (GalA-gamma-lact) in the presence of NAD, followed by the appearance of 2-keto-3-deoxy-D-galactonate (KDGal), pyruvate and glyceraldehyde. From 10 &mgr;moles only 6.6 &mgr;moles of GalA-gamma-lact were disappeared after 60 min of reaction indicating the presence of GalA-gamma-lactonase. Identification of GalA-gamma-lact was achieved by ascending paper chromatography. KDGal, pyruvate and glyceraldehyde were also chromatographically identified in the reaction mixture containing D-galactonate which suggests that D-galactonate is degraded into pyruvate and glyceraldehyde via the intermediate formation of KDGal. Such reactions are supposed to be catalyzed by an inducible D-galactonate dehydratase and a constitutive KDGal aldolase. The amount of KDGal, pyruvate and glyceraldehyde were found to be almost equivalent and the equilibrium of the reaction being toward the formation of KDGal. The apparent equilibrium constant (K(eq)) was calculated and found to be 0.5 x 10(-3) M. Results also proved the reversibility of the reaction catalyzed by KDGal aldolase of A. niger. In the light of the findings obtained from the degradation of D-galactose by cell-free extracts of A. niger grown on D-galactose and D-galactonate a nonphosphorolytic pathway was suggested to be operative for the degradation of D-galactose in extracts of A. niger.
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PMID:Evidence for a non-phosphorylated route of galactose breakdown in cell-free extracts of Aspergillus niger. 1142 38

The synthesis of 3-azido-3-deoxy, 3-amino-3-deoxy and 3-N-tert-butyloxycarbonyl-3-deoxy derivatives of 2-acetamido-2-deoxy-alpha,beta-D-mannose (N-acetyl-alpha,beta-D-mannosamine, ManNAc), is presented. The 3-azido-3-deoxy- and 3-N-tert-butyloxycarbonyl compounds were further characterised as their peracetates. A preliminary study has found that these C-3 nitrogen-substituted derivatives of ManNAc not to be substrates for Neu5Ac aldolase.
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PMID:Synthesis of C-3 nitrogen-containing derivatives of N-acetyl-alpha,beta-D-mannosamine as substrates for N-acetylneuraminic acid aldolase. 1143 70

d-Arabinose is a major sugar in the cell wall polysaccharides of Mycobacterium tuberculosis and other mycobacterial species. The reactions involved in the biosynthesis and activation of d-arabinose represent excellent potential sites for drug intervention since d-arabinose is not found in mammalian cells, and the cell wall arabinomannan and/or arabinogalactan appear to be essential for cell survival. Since the pathway involved in conversion of d-glucose to d-arabinose is unknown, we incubated cells of Mycobacterium smegmatis individually with [1-(14)C]glucose, [3,4-(14)C]glucose, and [6-(14)C]glucose and compared the specific activities of the cell wall-bound arabinose. Although the specific activity of the arabinose was about 25% lower with [6-(14)C]glucose than with other labels, there did not appear to be selective loss of either carbon 1 or carbon 6, suggesting that arabinose was not formed by loss of carbon 1 of glucose via the oxidative step of the pentose phosphate pathway, or by loss of carbon 6 in the uronic acid pathway. Similar labeling patterns were observed with ribose isolated from the nucleic acid fraction. Since these results suggested an unusual pathway of pentose formation, labeling studies were also done with [1-(13)C]glucose, [2-(13)C]glucose, and [6-(13)C]glucose and the cell wall arabinose was examined by NMR analysis. This method allows one to determine the relative (13)C content in each carbon of the arabinose. The labeling patterns suggested that the most likely pathway was condensation of carbons 1 and 2 of fructose 6-phosphate produced by the transaldolase reaction with carbons 4, 5, and 6 (i.e., glyceraldehyde 3-phosphate) formed by fructose-1,6 bisphosphate aldolase. Cell-free enzyme extracts of M. smegmatis were incubated with ribose 5-phosphate, xylulose 5-phosphate, and d-arabinose 5-phosphate under a variety of experimental conditions. Although the ribose 5-phosphate and xylulose 5-phosphate were converted to other pentoses and hexoses, no arabinose 5-phosphate (or free arabinose) was detected in any of these reactions. In addition, these enzyme extracts did not convert arabinose 5-phosphate to any other pentose or hexose. In addition, incubation of [(14)C]glucose 6-phosphate and various nucleoside triphosphates (ATP, CTP, GTP, TTP, and UTP) with cytosolic or membrane fractions from the mycobacterial cells did not result in formation of a nucleotide form of arabinose, although other radioactive sugars including rhamnose and galactose were found in the nucleotide fraction. Furthermore, no radioactive arabinose was found in the nucleotide fraction isolated from M. smegmatis cells grown in [(3)H]glucose, nor was arabinose detected in a large-scale extraction of the sugar nucleotide fraction from 300 g of cells. The logical conclusion from these studies is that d-arabinose is probably produced from d-ribose by epimerization of carbon 2 of the ribose moiety of polyprenylphosphate-ribose to form polyprenylphosphate-arabinose, which is then used as the precursor for formation of arabinosyl polymers.
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PMID:Biosynthesis of d-arabinose in Mycobacterium smegmatis: specific labeling from d-glucose. 1183 54

Capillary electrophoresis and on-column enzyme-catalyzed microreactor techniques were used to quantitate the reaction projects resulting from three model systems: i) the conversion of nicotinamide adenine dinucleotide (NAD) to nicotinamide adenine dinucleotide, reduced form (NADH) in the oxidation of glucose-6-phosphate (glc-6-p) to 6-phosphogluconate by glucose-6-phosphate dehydrogenase (G6PDH, EC 1.1.1.49); ii) the conversion of adenosine triphosphate (ATP) to adenosine diphosphate (ADP) and adenosine monophosphate (AMP) by hexokinase (HK, EC 2.7.1.1) and apyrase (APY, EC 3.6.1.5), respectively, in the conversion of glucose to glucose-6-phosphate and inorganic phosphate, respectively, and; iii) the conversion of fructose-1,6-bisphosphate to dihydroxyacetone phosphate and glyceraldehyde-3-phosphate by fructose-biphosphate aldolase (ALD, EC 4.1.2.13). Single and double microreactor techniques employing direct or indirect detection were used to follow the conversion of substrate to product(s). In addition, electrophoresis conditions including voltage, enzyme concentration, and mixing time of the reaction, were correlated to product distribution profiles.
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PMID:On-column enzyme-catalyzed microreactions using capillary electrophoresis: quantitative studies. 1193 61

The hyperthermophilic Archaeon Sulfolobus solfataricus metabolizes glucose by a non-phosphorylative variant of the Entner-Doudoroff pathway. In this pathway glucose dehydrogenase and gluconate dehydratase catalyze the oxidation of glucose to gluconate and the subsequent dehydration of gluconate to 2-keto-3-deoxygluconate. 2-Keto-3-deoxygluconate (KDG) aldolase then catalyzes the cleavage of 2-keto-3-deoxygluconate to glyceraldehyde and pyruvate. The gene encoding glucose dehydrogenase has been cloned and expressed in Escherichia coli to give a fully active enzyme, with properties indistinguishable from the enzyme purified from S. solfataricus cells. Kinetic analysis revealed the enzyme to have a high catalytic efficiency for both glucose and galactose. KDG aldolase from S. solfataricus has previously been cloned and expressed in E. coli. In the current work its stereoselectivity was investigated by aldol condensation reactions between D-glyceraldehyde and pyruvate; this revealed the enzyme to have an unexpected lack of facial selectivity, yielding approximately equal quantities of 2-keto-3-deoxygluconate and 2-keto-3-deoxygalactonate. The KDG aldolase-catalyzed cleavage reaction was also investigated, and a comparable catalytic efficiency was observed with both compounds. Our evidence suggests that the same enzymes are responsible for the catabolism of both glucose and galactose in this Archaeon. The physiological and evolutionary implications of this observation are discussed in terms of catalytic and metabolic promiscuity.
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PMID:Metabolic pathway promiscuity in the archaeon Sulfolobus solfataricus revealed by studies on glucose dehydrogenase and 2-keto-3-deoxygluconate aldolase. 1282 70


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