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) A lysosomal protease, a new cathepsin that inactivates glucose-6-phosphate dehydrogenase [EC 1.1.1.49] and some other enzymes and differs from cathepsin B [EC 3.4.22.1] was purified about 2,200-fold from crude extracts of rat liver by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, and DEAE Sephadex and CM-Sephadex column chromatographies. 2) The new cathepsin was markedly activated by the thiol-reagent, 2-mercaptoethanol and inhibited by monoiodoacetate. 3) The molecular weight of the new cathepsin was found by Sephadex G-75 column chromatography to be 22,000, which is smaller than that of cathepsin B. 4) The optimum pH of the enzyme for inactivation of glucose-6-phosphate dehydrogenase was pH 5.0--5.5. The enzyme was unstable in alkali and on heat treatment. 5) The rates of inactivation of glucose-6-phosphate dehydrogenase, apo-ornithine aminotransferase [EC 2.6.1.13], apo-tyrosine aminotransferase [EC 2.6.1.5], apo-cystathionase [EC 4.4.1.1], glucokinase [EC 2.7.1.2], glyceraldehyde-3-phosphate dehydrogenase [EC 1.2.1.12], and malate dehydrogenase [EC 1.1.1.37] by the new cathepsin were higher than those by cathepsin B. However aldolase [EC 4.1.2.13] was inactivated more rapidly by cathepsin B than by the new cathepsin. Lactate dehydrogenase [EC 1.1.1.27], glutamate dehydrogenase [EC 1.4.1.2] and alcohol dehydrogenase [EC 1.1.1.1] were not inactivated by either cathepsin. Unlike cathepsin B, the new cathepsin scarcely hydrolyzes N-substituted derivatives of arginine.
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PMID:Purification and properties of a new cathepsin from rat liver. 3 59

Cathepsin B from rat liver was purified to apparent homogeneity by cell-fractionation, freezing and thawing, acetone treatment, gel filtration, DEAE-Sephadex and CM-Sephadex column chromatography, and was crystallized. The purified enzyme formed spindle-shaped crystals and its homogeneity was proved by disc gel electrophoresis in the presence of sodium dodecyl sulfate and by ultracentrifugal analysis. Its s20,w value was 2.8 S and its relative molecular mass was calculated to be 22,500 (+/- 900) by sedimentation equilibrium analysis. Crystalline cathepsin B was shown to consist of four isozymes with isoelectric points between pH 4.9 and 5.3, the main isozyme having an isoelectric point of pH 5.0. The enzyme was irreversibly inactivated by exposure to weak alkali. The pH optimum was 6.0 with alpha-N-benzoyl-DL-arginine-4-nitroanilide as substrate. Amino acid analysis showed that the enzyme contained hexosamine, glucosamine and galactosamine. Cathepsin B inactivated aldolase, glucokinase, apo-ornithine aminotransferase, and apo-cystathionase, but the rates of inactivation of glucokinase, apo-ornithine aminotransferase, and apocystathionase were lower than that of aldolase. Studies by polyacrylamide gel electrophoresis in the presence and absence of sodium dodecyl sulfate showed that cathepsin B degraded apo-ornithine aminotransferase to two polypeptide chains differing in relative molecular mass and electrophoretic mobility.
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PMID:Crystallization and properties of cathepsin B from rat liver. 4 40

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

Setaria cervi, the filarial parasite inhabiting the Indian water buffalo (Bubalus bubalis Linn.) contained almost all the enzymes involved in glycogen degradation. Significant activities of glycogen phosphorylase, glucokinase, phosphoglucomutase, phosphoglucose isomerase, phosphofructokinase, FDP-aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphopyruvate hydratase, pyruvate kinase, lactate dehydrogenase glucose-6-phosphate dehydrogenase and 6-phosphogluconate dehydrogenase were detected in cell-free extracts of whole worms. The presence of PEP-carboxykinase, malate dehydrogenase, fumarase and fumarate reductase revealed the functioning of the PEP-succinate pathway in addition to phosphorylating glycolysis and pentose phosphate pathway in the parasite. Excepting fumarate reductase all other enzymes were localized in the particulate-free cytosol fraction, although small amounts of glycogen phosphorylase, aldolase and lactate dehydrogenase were also detected in the mitochondrial fraction.
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PMID:Setaria cervi: enzymes of glycolysis and PEP-succinate pathway. 86 May 72

The 11.5-kDa Zn(2+)-binding protein (ZnBP) was covalently linked to Sepharose. Affinity chromatography with a cytosolic subfraction from liver resulted in purification of a predominant 38-kDa protein. In comparable experiments with brain cytosol a 39-kDa protein was enriched. The ZnBP-protein interactions were zinc-specific. Both proteins were identified as fructose-1,6-bisphosphate aldolase. Experiments with crude cytosol showed zinc-specific interaction of additional enzymes involved in carbohydrate metabolism. From liver cytosol greater than 90% of the following enzymes were specifically retained: aldolase, phosphofructokinase-1, hexokinase/glucokinase, glucose-6-phosphate dehydrogenase, glycerol-3-phosphate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, and fructose-1,6-bisphosphatase. Glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, and most of triosephosphate isomerase remained unbound. From L-type pyruvate kinase only the phosphorylated form seems to interact with ZnBP. Using brain cytosol hexokinase, phosphofructokinase-1, and aldolase were completely bound to the affinity column, whereas glucose-6-phosphate isomerase, phosphoglycerate kinase, enolase, lactate dehydrogenase, pyruvate kinase, and most of triose-phosphate isomerase remained unbound. The behavior of glucose-6-phosphate dehydrogenase and glycerol-3-phosphate dehydrogenase from this tissue could not be followed. A possible function of ZnBP in supramolecular organization of carbohydrate metabolism is proposed.
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PMID:Key enzymes of carbohydrate metabolism as targets of the 11.5-kDa Zn(2+)-binding protein (parathymosin). 183 54

Independently controlled, inducible, catabolic genes in Pseudomonas aeruginosa are subject to strong catabolite repression control by intermediates of the tricarboxylic acid cycle. Mutants which exhibited a pleiotropic loss of catabolite repression control of multiple pathways were isolated. The mutations mapped in the 11-min region of the P. aeruginosa chromosome near argB and pyrE and were designated crc. Crc- mutants no longer showed repression of mannitol and glucose transport, glucose-6-phosphate dehydrogenase, glucokinase, Entner-Doudoroff dehydratase and aldolase, and amidase when grown in the presence of succinate plus an inducer. These activities were not expressed constitutively in Crc- mutants but exhibited wild-type inducible expression.
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PMID:Isolation and characterization of catabolite repression control mutants of Pseudomonas aeruginosa PAO. 190 70

Seven cytosolic enzymes with varying half-lives (ornithine decarboxylase, 0.9 h; tyrosine aminotransferase, 3.1 h; tryptophan oxygenase, 3.3 h; serine dehydratase, 10.3 h; glucokinase, 12.7 h; lactate dehydrogenase, 17.0 h; aldolase, 17.4 h) were found to be autophagically sequestered at the same rate (3.5%/h) in isolated rat hepatocytes. Autophagy was measured as the accumulation of enzyme activity in the sedimentable organelles (mostly lysosomes) of electrodisrupted cells in the presence of the proteinase inhibitor leupeptin. Inhibitors of lysosomal fusion processes (vinblastine and asparagine) allowed accumulation of catalytically active enzyme (in prelysosomal vacuoles) even in the absence of proteolytic inhibition, showing that no inactivation step took place before lysosomal proteolysis. The completeness of protection by leupeptin indicates, furthermore, that a lysosomal cysteine proteinase is obligatorily required for the initial proteolytic attack upon autophagocytosed proteins. The experiments suggest that sequestration and degradation of normal cytosolic proteins by the autophagic-lysosomal pathway is a nonselective bulk process, and that nonautophagic mechanisms must be invoked to account for differential enzyme turnover.
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PMID:Nonselective autophagy of cytosolic enzymes by isolated rat hepatocytes. 239 70

The enzyme activities involved in fructose metabolism were measured in samples of human liver. On the basis of U/g of wet-weight the following results were found: ketohexokinase, 1.23; aldolase (substrate, fructose-1-phosphate), 2.08; aldolase (substrate, fructose-1,6-diphosphate), 3.46; triokinase, 2.07; aldehyde dehydrogenase (substrate, D-glyceraldehyde), 1.04; D-glycerate kinase, 0.13; alcohol dehydrogenase (nicotinamide adenine dinucleotide [NAD]) substrate, D-glyceraldehyde), 3.1; alcohol dehydrogenase (nicotinamide adenine dinucleotide phosphate [NADP]) (substrate, D-glyceraldehyde), 3.6; and glycerol kinase, 0.62. Sorbitol dehydrogenases (25.0 U/g), hexosediphosphatase (4.06 U/g), hexokinase (0.23 U/g), and glucokinase (0.08 U/g) were also measured. Comparing these results with those of the rat liver it becomes clear that the activities of alcohol dehydrogenases (NAD and NADP) in rat liver are higher than those in human liver, and that the values of ketohexokinase, sorbitol dehydrogenases, and hexosediphosphatase in human liver are lower than those values found in rat liver. Human liver contains only traces of glycerate kinase. The rate of fructose uptake from the blood, as described by other investigators, can be based on the activity of ketohexokinase reported in the present paper. In human liver, ketohexokinase is present in a four-fold activity of glucokinase and hexokinase. This result may explain the well-known fact that fructose is metabolized faster than glucose.
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PMID:Enzymes of fructose metabolism in human liver. 438 49

Spirillum itersonii ATCC 12639 utilized d-fructose but neither d-glucose nor d-gluconate as a sole source of carbon and energy. The substrate saturation kinetics for d-fructose and d-glucose uptake by whole cells indicated the presence of a carrier-mediated transport system for d-fructose but not for d-glucose. The d-fructose uptake activity was induced (10- to 12-fold increase) during growth on d-fructose-Casamino Acids (CA) or d-glucose-CA medium, but not CA alone. d-Fructose uptake activity was stimulated by Na(+) or Li(+), but was inhibited by KCN, NaN(3), 2,4-dinitrophenol, and p-chloromercuribenzoate. High specific activities of glucokinase, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydratase, and 2-keto-3-deoxy-6-phosphogluconate aldolase were detected in extracts of cells cultured on d-fructose-CA medium. These enzymatic activities were undetectable in extracts of cells grown in CA or succinate-CA medium. No decrease in the maximally induced specific activities of these enzymes occurred after the addition of succinate to cells during exponential growth on d-fructose-CA. Fructose 1,6-diphosphate aldolase and glucose-6-phosphate isomerase specific activities were approximately the same irrespective of cultural conditions. These results indicated that d-glucose was not utilized by cells of S. itersonii because this bacterium was impermeable to this hexose.
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PMID:Transport and catabolism of D-fructose by Spirillum itersomii. 480 97

Clostridium thermocellum was shown to ferment glucose in a medium containing salts and 0.5% yeast extract. An active glucokinase was obtained with improved conditions for growth, assay, and preparation of cell extracts. Cell extracts appear to contain a glucokinase inhibitor that interferes with the assays at high protein concentrations. Glucokinase activity is stimulated about 60% by pretreatment with dithiothreitol. Little or no fructokinase or mannokinase activity was detected in cell extracts. The absence of glucokinase in mannitol-grown cells, the increase in glucokinase activity upon incubation of cell suspensions with glucose, and the lack of increase in activity when chloramphenical is added are evidence that glucokinase is an inducible enzyme. The following enzymes were detected in cell extracts (the enzyme activities are shown in parentheses are micromoles per minute per milligram or protein at 27 C): glucokinase (0.48), phosphoglucose isomerase (0.73), fructose 6-phosphate kinase (0.24), fructose diphosphate aldolase (0.59), glyceraldehyde 3-phosphate dehydrogenase (0.53), triose phosphate isomerase (0.13), phosphoglycerate kinase (0.20), phosphoglycerate mutase (0.20), enolase (0.28), pyruvic kinase (0.13), and lactic dehydrogenase (0.13). Glucose 6-phosphate dehydrogenase activity was absent or very low (0.0002) and 6-phosphogluconate dehydrogenase activity also was relatively low (0.015). From these data, it is proposed that carbohydrate metabolism in C. thermocellum proceeds by the Embden-Meyerhof pathway.
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PMID:Utilization of glucose by Clostridium thermocellum: presence of glucokinase and other glycolytic enzymes in cell extracts. 554 Oct 8


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