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)

13C NMR shows fructose 6-phosphate and fructose 1,6-bisphosphate to contain respectively 4.1 and 2.0% keto isomer at room temperature. The lower value for fructose 1,6-bisphosphate can be attributed to the electron-withdrawing effect of the C-1 phosphate. Measurements of the ring-opening rates of the alpha and beta anomers of fructose, 1,6-bisphosphate by an NMR line-broadening technique show them to be about 8 and 35 S-1, respectively, at pH 7.2, and 25degreesC. The value for the predominant beta anomer is threefold greater than the turnover rate of muscle aldolase so that, if the kinetic properties of the keto form were favorable, the reaction could proceed entirely through the keto form in solution. The kinetic properties of a fructose 1,6-bisphosphate(keto) analogue, 5-deoxyfructose, 1,6-bisphosphate, in the muscle aldolase reaction are more favorable (Vmax = 2.6, Km = 0.11 X 10(-6) M) than those of fructose 1,6-bisphosphate total (Vmax = 1, Km = 2.3 X 10(-6)M), giving a value of Vmax/Km that is 56 times greater for the 5-deoxy analogue. At the 2.0% concentration of the keto form this is sufficient to account for the steady-state rate and requires that the beta form, present at 40 times greater concentration, contributes little to the cleavage rate. With yeast aldolase the cleavage rate can be explained by the rapid spontaneous ring opening and reaction of the keto form with the enzyme. In view of the high rate of ring opening and the excellent properties of the keto form, previous rapid kinetic studies favoring action of cyclic forms may require reevaluation.
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PMID:Fructose 1,6-bisphosphate: isomeric composition, kinetics, and substrate specificity for the aldolases. 77 19

In the reaction catalysed by deoxyribose 5-phosphate aldolase (2-deoxy-D-ribose 5-phosphate acetaldehyde-lyase, EC 4.1.2.4) from Salmonella typhimurium, almost complete equilibration of the methyl-group protons of the product, acetaldehyde, occurs before its release from the enzyme surface. This phenomenon does not allow the stereo-chemical course of the reaction to be determined by using hydrogen-isotope labelling of the methyl group to generate a chiral centre.
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PMID:An apparent lack of stereospecificity in the reaction catalysed by deoxyribose 5-phosphate aldolase due to methyl-group rotation and enolization before product release. 79 Dec 68

Cell-free extracts of Rickettsia typhi were tested for activities of enzymes of the tricarboxylic acid cycle, of glutamate catabolism, and of glycolysis. The organisms were grown in the yolk sacs of chicken embryos, harvested shortly before the time of embryo death, purified by Renografin density gradient centrifugation, and ruptured in a French pressure cell. The following enzymatic activities were demonstrated: high levels of malate dehydrogenase (MDH), moderate levels of glutamate-oxaloacetate transaminase, glutamate, succinate, and isocitrate dehydrogenases, and citrate synthase, and low levels of glutamate-pyruvate transaminase. The specific activities of some of these enzymes were higher when the rickettsiae were harvested at a time of active proliferation, 3 to 4 days prior to embryo death. Rickettsial MDH was differentiated from host MDH by its migration pattern on polyacrylamide gel electrophoresis. The activities of MDH and two other dehydrogenases, demonstrable after the cells had been disrupted, were absent from purified, intact rickettsial preparations. No activity was detected for glucose-6-phosphate, 6-phosphogluconate, glyceraldehyde-3-phosphate, lactate dehydrogenases, phosphoglucose isomerase, fructoaldolase, or pyruvate kinase. Our results suggest that extracts of R. typhi that contain demonstrable enzymes involved in the catabolism of glutamate and tricarboxylic acid cycle intermediates, unlike Coxiella burnetti, lack detectable glycolytic activity.
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PMID:Enzymatic activities of cell-free extracts of Rickettsia typhi. 82 Jun 44

The process of enzymatic aging was studied in livers of adult and senescent rats for aldolase B. No "cross-reacting material" was found in livers of 27 to 30-month-old rats, estimated by the ratio aldolase activity-antigen amount. The activity towards the two substrates of aldolase, fructose 1,6-diphosphate and fructose 1-phosphate did not vary in senescent animals. Moreover, other physico-chemical properties of the enzyme such as thermal inactivation, immunological reactivity and Michaelis constant remain unchanged. These results provide arguments against the occurrence of errors in protein synthesis as a cause of aging.
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PMID:Aldolase B in the liver of senescent rats. 82 40

In 38 patients with chronic renal insufficiency of different degree of severity examinations of the stationary concentration of the adenine nucleotides in the erythrocytes were carried out. It was shown that in the red blood cells of uraemics a genuine increase of the concentration of these compounds occurs, in which case the adenosine triphosphate dominates absolutely as well as relatively. In individual cases erytho-cyctic ATP-values of more than 3 micron mol pro ml cells may be achieved. The increase of the ATP-concentration in the red blood cells correlates with the degree of severity of the renal insufficiency and the renal anaemia. The hyperphosphataemia occurring as a rule in renal insuficiency is of causal importance for the increase of ATP. By a consecutive increase of the intracellular phosphate level and by influence on different steps of enzymes (phosphofructokinase, aldolase, glycerin aldehyde phosphate dehydrogenase) and changed regulations it effected an activation of the glycolysis. The increase of the plasma adenine and plasma adenosine concentration plays apparantly an accessory role for the increase of the concentration of the adenine nucleotides existing in the erythrocytes. Together with an increased concentration of 2,3-diphosphogycerate (2,3-DPG) the increase of the ATP-level has an effect on the oxygen transport function function of haemoglobin in the sense of a facilitation of the O2-output. These processes explain the relative adaption of patients with chronic renal insufficiency to renal anaemias of partly high degree.
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PMID:[Adenine nucleotide- and 2,3-diphosphoglycerate metabolism in human erythrocytes in chronic kidney insufficiency]. 84 44

1. Treatment with methyl acetimidate was used to probe the topography of the tetrameric fructose 1,6-diphosphate aldolase from ox liver. A single treatment with imido ester in the presence or absence of 20mM-fructose 1,6-diphosphate caused the number of amino groups in the enzyme to fall to approx. 30% of the starting number (assumed to be 30 per subunit). The catalytic activity of the aldolase modified in the presence of fructose 1,6-diphosphate was unaffected, whereas that of the enzyme modified in the absence of substrate fell by about 20%. 2. Use of methyl [1-14C]acetimidate and small-scale methods of protein chemistry showed that the amino group of lysine-27 (the numbering is that of the highly homologous rabbit muscle enzyme) is essentially unavailable for amidination in the native enzyme and is therefore predicted to be buried in a hydrophobic environment, probably in the form of an ion-pair with a negatively charged side-chain carboxyl group. All the other lysine residues that reacted poorly with methyl acetimidate in the native enzyme (a total of 7) were found to be within the primary structure bounded by lysine-107 and lysine-227. An important member of this group of lysine residues displaying aberrant reactivity is lysine-227, which is known to form an imine with the substrate as part of the catalytic mechanism of the enzyme. 3. The results of the amidination experiments can be correlated in an interesting way with previous studies of thiol-group modification in the aldolases. Taken together, and arguing in part by analogy with the results of identical experiments with glyceraldehyde 3-phosphate dehydrogenases where the three-dimensional structure is known [Lambert & Perham (1977) Biochem. 4. 161. 49-62], they suggest that the region of primary structure from residues 107-227 may form the whole or part of a three-dimensional structural feature, perhaps a folding domain. A three-dimensional structure deduced from X-ray-crystallographic analysis will be needed to interpret these findings more closely. 4. The amino groups of lysine residues are commonly thought to reside at the 'surface' of protein structures. The patterns of specific lysine residues in glyceraldehyde 3-phosphate dehydrogenases and in aldolases that have been found to react poorly with methyl acetimidate in the native enzymes can be attributed to intramolecular ionic interactions deep in hydrophobic pockets and at the protein 'surface'. Such ionic interactions may contribute significantly to the stability of a given protein.
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PMID:Intramolecular ionic interactions of lysine residues and a possible folding domain in fructose diphosphate aldolase. 85 25

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

Enzymes essential to the operation of the Embden-Meyerhof glycolytic pathway, the Entner-Duodoroff pathway and oxidative pentose phosphate pathway were present in Thiobacillus A2 grown on glucose and other sugars. Radiorespirometry under various conditions with Thiobacillus A2 oxidising glucose specifically labelled with 14C in carbon atoms 1, 2, 3, 3 + 4, 6 or universally labelled demonstrated the simultaneous operation of the Embden-Meyerhof (48%), Entner-Doudoroff (28%), and pentose phosphate (24%) pathways in release of carbon dioxide from glucose. Growth on succinate, or autotrophically on formate or thiosulphate resulted in repression of most enzymes of the pathways, but high aldolase levels were retained indicating its role in gluconeogenesis and the Calvin cycle. Different fructose diphosphatase activities were found in succinate- and thiosulphate-grown organisms. The results indicate that all three major catabolic pathways for glucose function in Thiobacillus A2 grown on sugars. Thiobacillus acidophilus showed a different radiorespirometric pattern and apparently used the Entner-Duodoroff (64.5%) and pentose phosphate (35.5%) pathways, but showed unusually high release of carbon atom 6, as was also found for T. ferrooxidans.
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PMID:Simultaneous operation of three catabolic pathways in the metabolism of glucose by Thiobacillus A2. 87 64

The lactate and pyruvate levels, as well as acid and alkaline phosphatase, lactate dehydrogenase, glucose-6-phosphate dehydrogenase, glutaminic acid-oxalacetic acid transaminase and aldolase levels of rat liver homogenizates were measured at 24 degrees C and 38 degrees C during 120 min ischaemia from 0 to the 120th min. With the exception of transaminase and aldolase, the other enzymes were also enzyme-histochemically studied. The early lesions of the liver can be detected, both the quantitative laboratory tests and enzyme histochemical studies. The deviations from normal, observed at 24 degrees C between the 60th and 100th min, and at 38 degrees C between the 30th and 60th min, might be signs of irreversible lesions. Fractionated study of the liver homogenizate improves the assessability of enzyme determinations. In the course of "warm" ischaemia, the liver lysosomal lesions are early symptoms. Parallel to the breakdown of aerobic glycolysis lactic acid, fermentation, and an active pentose phosphate cycle can be detected. Quantitative testing of the liver homogenizate and enzyme histochemical observation of the hepatic tissue, might be a suitable method for the assessment of ischaemic liver lesions.
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PMID:Effect of ischaemia on the enzyme activity of the hepatic tissue. 89 61

In order to diagnose hereditary fructose intolerance up to now, there were only the dangerous fructose-load and the biochemical evidence of this metabolic defect from biopsies of liver, intestine or kidney. Since there are no screening tests nor tests for heterocygote carriers or prenatal diagnostic procedures, we tested a simple method to determine serum activities of the two enzymes concerned in this defect (fructose-1-phosphate aldolase, fructose-1,6-diphosphate aldolase). Even in completely healthy children we could measure both activities in a good range. Children with known liver lesion caused other than HFI had significantly increased activities of both enzymes. In 4 cases with HFI we could not measure any activity of fructose-1-phosphate aldolase and a decreased activity of fructose-1,6-di-phosphate aldolase in serum, despite an apparently damaged liver. We propose to define those two serum activities in any case of an obscure liver lesion, frequent vomiting and postprandial hypoglycemia in early childhood, in order to exclude HFI or to demonstrate its possible presence.
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PMID:[Diagnostic procedures in hereditary fructose intolerance (author's transl)]. 90 45


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