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)

Seven enzymes of the Embden-Myerhof pathway of glycolysis were assayed in hypotonically treated epididymal sperm from mature rabbits. These were: fructose-biphosphate aldolase, triosephosphate isomerase, glyceraldehydephosphate dehydrogenase, 3-phosphoglyceromutase, enolase, pyruvate kinase, and lactate dehydrogenase. These enzymes were firmly enough bound to the cell structure to resist removal by washing after hypotonic treatment and had maximal activities comparable to, or greater than, the rate of mitochondrial pyruvate oxidation, so that rapid oxygen uptake was observed with intermediates of the glycolytic pathway. The activity of lactate dehydrogenase in a typical preparation of hypotonically treated cells was 5.3 mumoles/minute x 10(9) cells at 25 degrees C for pyruvate reduction in the hypotonically treated cells and 4.8 mumoles/minute x 10(9) cells in the thrice-washed hypotonically treated cells. The Km for pyruvate was 1.4 mM while that for lactate was 4.4 mM. By contrast, the maximal activity of pyruvate oxidation by mitochondria was 0.10 microgram atom of oxygen/minute x 10(9) cells, corresponding to 0.020 mumole of pyruvate/minute x 10(9) cells, and the Km for pyruvate was 5 microM. These enzyme parameters favor high lactate production from glucose in aerobic glycolysis.
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PMID:Energy metabolism of spermatozoa. V. The Embden-Myerhof pathway of glycolysis: activities of pathway enzymes in hypotonically treated rabbit epididymal spermatozoa. 80 42

Optimal concentrations of the essential components for analyzing the activity of each enzyme associated with glycolysis and gluconeogenesis in rabbit periodontal ligament were examined, and enzyme assay systems for 15 enzymes including 22 reactions were established using triethanolamine buffer. Specific activities of all the enzymes, except for the gluconeogenic reaction of phosphoglycerate kinase, were systematically evaluated using the optimum buffer for each enzyme, since the activity of each enzyme varied depending on the buffer used. For glycolysis, the activity levels of hexokinase and 6-phosphofructokinase were very low, and consequently these enzyme reactions were inferred to be the rate-limiting steps. For gluconeogenesis, fructose 1,6-bisphosphatase and aldolase activities were extremely low, and the activities of glucose 6-phosphatase, phosphoenolpyruvate carboxykinase and pyruvate carboxylase were undetectable. These results suggest that the periodontal ligament may have no gluconeogenesis capability. With a rise in pH, the activities of the key enzymes of glycolysis gradually increased, and a specific "crossover" point was found between the activities of glyceraldehyde-phosphate dehydrogenase and phosphoglyceromutase. In addition, the activity of fructose 1,6-bisphosphatase, one of the key enzymes of gluconeogenesis, was markedly increased with a rise in pH, although pH changes had no effect on aldolase activity. Consequently, alkaline pH appeared to result in overall stimulation of glycolysis.
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PMID:Enzymatic regulation of glycolysis and gluconeogenesis in rabbit periodontal ligament under various physiological pH conditions. 165 53

A marked reduction of granulocyte chemotactic function accompanies the storage of granulocyte concentrates. Since chemotaxis is energy dependent, we studied energy metabolism in stored neutrophils. We and others have reported that stored neutrophils have a defect in their energy metabolism. We found that defective adenosine triphosphate maintenance in stored neutrophils was occult in resting cells, but was unmasked by an energy-intensive stimulus, phagocytosis. In studies reported here, we sought to determine if defective adenosine triphosphate maintenance during granulocyte storage was related to altered glycolytic enzyme activity. We studied the activity of glycolytic enzymes in fresh and stored, resting and stimulated (opsonized zymosan) neutrophils. The following enzyme activities showed no major changes during storage, in resting or stimulated neutrophils: hexokinase, phosphofructokinase, aldolase, glucose phosphate isomerase, triose phosphate isomerase, glyceraldehyde phosphate dehydrogenase, phosphoglycerate kinase, phosphoglyceromutase, enolase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutathione reductase, and glutathione peroxidase. In contrast, pyruvate kinase activity consistently increased during storage. In 6 units, pyruvate kinase activity increased by 75 percent after 24 hours of storage at room temperature and by 198 percent after 48 hours. The storage-associated increase in pyruvate kinase activity was not inhibited by cycloheximide. Stimulation of neutrophils by phagocytosis of opsonized zymosan also produced striking increases in the pyruvate kinase activity of both fresh and stored cells. Additional studies indicated that the increases in pyruvate kinase activity observed during storage and after phagocytosis were associated with an increase in the availability of pyruvate kinase activity in the supernatant fraction of neutrophil sonicates. Total pyruvate kinase activity in sonicates of neutrophils was unchanged by storage or particle ingestion.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:Glycolytic enzymes of stored granulocytes. 632 24

In extracts of adult Angiostrongylus cantonensis, the activities of enzymes including glucokinase, phosphoglucoisomerase, phosphofructokinase, aldolase, triosepho sphate isomerase, glyceraldehydephosphate dehydrogenase, phosphoglycerokinase, phosphoglyceromutase, enolase, pyruvate kinase, lactate dehydrogenase, pyruvate decarboxylase, alcohol dehydrogenase, glucose 6-phosphate dehydrogenase, glycerophosphate dehydrogenase and pyruvate dehydrogenase complex were demonstrated. The present of significant activity of glycerophosphate dehydrogenase and glucose 6-phosphate dehydrogenase may indicate the possibility of an operative of alpha-glycerophosphate and pentose phosphate pathway.
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PMID:Glycolytic enzymes in juvenile and adult Angiostrongylus cantonensis. 711 11

Purified glycolytic enzymes were individually chromatographed through columns of Sepharose 4B containing a covalently bound F-actin-tropomyosin complex. Five of these enzymes, aldolase, glyceraldehyde-phosphate dehydrogenase, lactate dehydrogenase, pyruvate kinase, and phosphoglycerate kinase were able to interact with the complex. Glucosephosphate isomerase, triosephosphate isomerase, phosphoglycerate phosphomutase, and enolase did not bind to the F-actin-tropomyosin matrix. One nonbinding enzyme, phosphoglycerate phosphomutase, was observed to interact with F-actin-tropomyosin if the column was preloaded with lactate dehydrogenase. Since at least four other glycolytic enzymes did not associate with actin directly, it is suggested that if a glycolytic enzyme complex exists, these nonadsorbing enzymes must interact with one or more of the enzymes which do bind to actin.
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PMID:Interaction of muscle glycolytic enzymes with thin filament proteins. 729 40

Infective (L3) larvae of Strongyloides ratti (homogonic strain) were freeze-clamped (-196 degrees C) and the steady-state content of the glycolytic, Krebs tricarboxylic acid (KTA)-cycle intermediates and adenine nucleotides analysed. Comparison of the mass-action ratios (MARs) of the glycolytic enzymes with their apparent equilibrium constants (K9eq) indicate that phosphoglucomutase, glucosephosphate isomerase, triosephosphate isomerase, phosphoglyceromutase and phosphopyruvate hydratase reactions were all at or near equilibrium, whilst hexokinase, phosphofructokinase and pyruvate kinase were displaced from equilibrium. The S. ratti aldolase and myokinase appear to be somewhat displaced from equilibrium and thus may have pseudoregulatory roles. The adenylate energy charge (AEC), ATP/ADP ratio and the available adenylate energy (AAE) indices were 0.9 +/- 0.04, 8.76 +/- 1.5 and 397 +/- 43, respectively. The free [NAD+]/[NADH+H+] ratio of the cytoplasmic compartment of S. ratti L3 larvae calculated employing the steady-state content of the oxidised and reduced substrates of lactate dehydrogenase (E.C. 1.1.1.27) and the combined glyceraldehyde 3-phosphate dehydrogenase (E.C. 1.2.1.12)/3-phosphoglycerate kinase (E.C. 2.7.2.3) system were ca. 523 and 1200, respectively. The free[NAD+]/[NADH+H+] ratio in the mitochondrial compartment of S. ratti L3 larvae calculated using the malate dehydrogenase (E.C. 1.1.1.37) equilibrium was found to be 1962:1. The data is discussed with respect to the predominantly aerobic nature of the energy metabolism of the L3 larvae.
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PMID:Steady-state content of glycolytic/tricarboxylic acid-cycle intermediates, adenine nucleotide pools and the cellular redox-status in the infective (L3) larvae of (homogonic) Strongyloides ratti. 762 25

To investigate whether the energy derived from glycolysis is functionally coupled to Ca2+ active transport in sarcoplasmic reticulum (SR), we determined whether glycolytic enzymes were associated with SR membranes and whether metabolism through these enzymes was capable of supporting 45Ca transport. Sealed right-side-out SR vesicles were isolated by step sucrose gradient from rabbit skeletal and cardiac muscle. Intravesicular 45Ca transport was measured after the addition of glycolytic substrates and cofactors specific for each of the glycolytic reactions being studied or after the addition of exogenous ATP and was expressed as transport sensitive to the specific Ca(2+)-ATPase inhibitor thapsigargin. We found that the entire chain of glycolytic enzymes from aldolase onward, including aldolase, GAPDH, phosphoglycerate kinase (PGK), phosphoglyceromutase, enolase, and pyruvate kinase (PK), was associated with SR vesicles from both cardiac and skeletal muscle. Iodoacetic acid, an inhibitor of GAPDH, eliminated 45Ca transport supported by fructose-1,6-diphosphate, the substrate for aldolase, but transport was completely restored by phosphoenolpyruvate (the substrate for PK), indicating that both of the ATP-producing glycolytic enzymes, GAPDH/PGK and PK, were associated with the SR and functionally capable of providing ATP for the Ca2+ pump. Addition of a soluble hexokinase ATP trap eliminated 45Ca transport fueled by exogenous ATP but had markedly less effect on 45Ca transport supported by endogenously produced ATP (via glycolysis). Similarly, at very low concentrations of ATP and ADP (10 to 50 nmol/L), ATP that was produced endogenously from ADP and phosphoenolpyruvate supported 15-fold more 45Ca transport than ATP that was supplied exogenously at the same concentration. These results are consistent with functional coupling of glycolytic ATP to Ca2+ transport and support the hypothesis that ATP generated by SR-associated glycolytic enzymes may play an important role in cellular Ca2+ homeostasis by driving the SR Ca2+ pump.
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PMID:Functional coupling between glycolysis and sarcoplasmic reticulum Ca2+ transport. 778 86

1. Electron microscopic studies of the sieve tube sap obtained from the secondary phloem of Robinia pseudoacacia by the method of Hartig (1860) showed the presence of well developed mitochondria in addition to membrane fragments. 2. In this sieve tube sap the following enzymes could be detected qualitatively: UTP-glucose-1-phosphate-uridyl transferase, UDPG-fructose glucosyl transferase, glucose-6-phosphate dehydrogenase, hexokinase (for glucose and fructose), phosphohexose isomerase, phosphofructokinase, and UDPG-pyrophosphatase. 3. The following enzymes were determined quantitatively: phosphorylase, amylase, aldolase, triosephosphate isomerase, NAD(+)-dependent glyceraldehyde-3-phosphate dehydrogenase, phosphoglyceromutase, enolase, pyruvate kinase, pyruvate decarboxylase, alcohol dehydrogenase, isocitrate dehydrogenase, fumarase, malate dehydrogenase, glutamate-pyruvate transaminase, glutamate dehydrogenase, glutamate-oxalacetate transaminase, and anorganic pyrophosphatase. 4. The following enzymes could not be detected: UDGP dehydrogenase, UDPG-fructose-6-phosphate-glucosyltransferase, invertase, phosphoglucomutase, lactate dehydrogenase, and citrate synthase. 5. The enzyme pattern in the sieve tube saps of Tilia platyphyllos, Carpinus betulus, Fraxinus americana, Quercus borealis maxima, and Salix viminalis is qualitatively similar to that of Robinia, but shows quantitative differences (as far as analyzed). 6. The meaning of the results for the metabolism and function of the sieve tubes in situ is discussed.
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PMID:[Enzyme activities in the sieve tube sap of Robinia pseudoacacia L. and of other tree species]. 2449 58

Isolation of tissue fragments from the potato tuber can initiate either periderm formation including suberin synthesis or cell proliferation without cicatrization effects. TCA-cycle activity has been shown to develop only in causal correlation with suberin synthesis (Lange, 1970). Biochemical pathways of carbohydrate metabolism are analysed by investigating the changing levels of 10 intermediates and the activities of 12 corresponding enzymes. Differences between the metabolic kinetics of the two contrasting types of tissue are discussed as the biochemical background of different respiratory behaviour and different histogenetic development.Glucose and pyruvate as well as all triose- and hexosephosphates investigated except 6-phospho-gluconate generally show an intensive rise in concentration after derepression with subsequent degradation. In several cases not a concomitant rise but rather a contrary drift between the concentration of metabolites and the activity of corresponding enzymes is observed, e.g. phosphoglucomutase/glucose-6-phosphate, enolase/phosphoenolpyruvate. This phenomenon is connected with the occurrence of suberin synthesis and remains totally absent in proliferating tissue.After derepression the pentose phosphate shunt (6-phosphogluconate-dehydrogenase) is strongly activated independently of different histogenetic processes. On the other hand, the glycolytic pathway via fructose-6-phosphate becomes more effective in suberizing tissue, as is indicated by enhanced activity of phosphoglucoisomerase and accumulation of F-6-P.Little or no difference can be found with regard to hexokinase, triosephosphateisomerase, aldolase and pyruvate-kinase; on the other hand suberin formation strongly stimulates phosphoglyceromutase. From the high activity of the TCA-cycle in suberin synthesizing cells it must be concluded that acetyl-CoA is formed at a high rate by oxidative decarboxylation of pyruvate, which leads finally to citrate synthesis. Measurements of different steps of pyruvate metabolism and respiration suggest an inhibition of this pathway in proliferating tissue. Sim a taneously certain compensatory reactions are activated. The activity of glutamaulpyruvate-transaminase increases considerably, whereas it is almost entirely eliteinated in suberin synthesizing cells. Moreover, malic enzyme activity showsmgreater increase in proliferating tissue, and large pools of pyruvate, phospho(enol)-pyruvate, and 2-phospho-glycerate are accumulated. The difference in the glycolytic metabolism of the two tissues suggests a suppression of periderm formation and its substitution by cell proliferation as a result of insufficient production of precursors of suberin biosynthesis such as acetyl-CoA and fatty acids.
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PMID:[Enzyme activities and substrate levels of carbohydrate metabolism in proliferating and suberin synthesizing potato tuber cells]. 2449 78