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)

Approximately 23% of the glycolytic enzyme aldolase in the perinuclear region of Swiss 3T3 cells is immobile as measured by FRAP. Previous studies suggest that the immobile fraction may be associated with the actin cytoskeleton (Pagliaro, L. and D. L. Taylor. 1988. J. Cell Biol. 107:981-991), and it has been proposed that the association of some glycolytic enzymes with the cytoskeleton could have functional significance, perhaps involving a fundamental relationship between glycolysis, cytoplasmic organization, and cell motility. We have tested the effect of a key glycolytic inhibitor and an actin cytoskeletal modulator on the mobility of aldolase in living cells directly, using fluorescent analog cytochemistry and FRAP. We report here that the competitive hexokinase inhibitor 2-deoxyglucose releases the bound fraction of aldolase in 3T3 cells within 10 min, and that this process is reversible upon washout of the inhibitor. A similar result is produced with the actin-binding agent, cytochalasin D. These results are consistent with models in which glycolytic enzymes are not exclusively diffusion-limited, soluble proteins, but may exist partially in the solid phase of cytoplasm. Such organization has significant implications for both the modulation of cytoplasmic structure and for cellular metabolism.
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PMID:2-Deoxyglucose and cytochalasin D modulate aldolase mobility in living 3T3 cells. 150 Apr 28

The effect of estradiol-17 beta on the activities of glycolytic enzymes from female rat brain was studied. The following enzymes were examined: hexokinase (HK, EC 2.7.1.1), phosphofructokinase (PFK, EC 2.7.1.11), aldolase (EC 4.1.2.13), glyceraldehyde-3-phosphate dehydrogenase (EC 1.2.1.12), phosphoglycerate kinase (EC 2.7.2.3), phosphoglycerate mutase (EC 2.7.5.3), enolase (EC 4.2.1.11) and pyruvate kinase (PK, EC 2.7.1.40). The activities of HK (soluble and membrane-bound), PFK and PK were increased after 4 h of hormone treatment, while the others remained constant. The changes in activity were not seen in the presence of actinomycin D. The significant rise of the activities of the key glycolytic enzymes was also observed in the cell culture of mouse neuroblastoma C1300 treated with hormone. Only three of the studied isozymes, namely, HKII, B4 and K4 were found to be estradiol-sensitive for HK, PFK and PK, respectively. The results obtained suggest that rat brain glycolysis regulation by estradiol is carried out in neurons due to definite isozymes induction.
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PMID:Rat brain glycolysis regulation by estradiol-17 beta. 153 2

The association of glycolytic enzymes with the particulate fraction of the cell was assessed in the brain of the freshwater turtle, Pseudemys scripta elegans, using three different methodologies. Each method showed that a large percentage of each of eight enzymes was bound in brain. The effect of environmental anoxia (5 or 20 h submergence in N2-bubbled water at 7 degrees C) on the distribution of enzymes between free and bound states was analyzed. All three techniques showed a significant increase in the percentages of brain aldolase and glyceraldehyde-3-phosphate dehydrogenase bound during anoxia and no change in lactate dehydrogenase or creatine kinase binding. Two methodologies also showed an increase in the percent bound during anoxia for hexokinase, phosphofructokinase, and phosphoglycerate kinase. An increased association of glycolytic enzymes with structural elements of the cell during anoxia may physically position the glycolytic pathway to facilitate coupling between this ATP-generating pathway and ATP-utilizing processes, such as membrane ion pumps.
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PMID:Subcellular enzyme binding and the regulation of glycolysis in anoxic turtle brain. 153 98

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

Three cell lines established from human gliomas were found to differ in the capacity to phosphorylate the glycolytic enzyme pyruvate kinase in vitro. Phosphorylation in the glioblastoma cell line U-138 was more pronounced than in the glioma cell line Hs 683 and in the glioblastoma cell line A-172. All 3 cell lines showed similar pyruvate kinase isozyme patterns and expressed about 90% K-type and 10% M-type subunits. So, differences in pyruvate kinase phosphorylation could not be explained by differences in the availability of the appropriate substrate, being pyruvate kinase type K. As in gliomas, phosphorylation could specifically and almost completely be inhibited by fructose-1,6-bisphosphate. In order to investigate a potential physiological significance of the phosphorylation of pyruvate kinase, we have characterized these cell lines for several glycolytic parameters. In U-138 cells, the production of lactate appeared to be 2 times higher as compared with A-172 and Hs 683 cells under normal growth conditions and even 4 times higher under low glucose culture regime. The efflux of lactate correlated with the pyruvate kinase phosphorylation pattern in the cell lines. In none of the cell lines could the lactate production be stimulated by glutamine as additional energy source under low glucose culture conditions. The higher glycolytic flux in U-138 cells was not accompanied by higher glycolytic enzyme activities. The isozyme patterns of hexokinase, pyruvate kinase, aldolase, enolase and lactate dehydrogenase in the cell lines were nearly identical and resembled the patterns previously described for solid gliomas. However, the isozyme composition of phosphofructokinase in the cell lines differed from the situation in gliomas. While in gliomas the expression of L-type phosphofructokinase is favored, in the glioma cell lines, we found an increase in the expression of C-type subunits.
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PMID:Phosphorylation of pyruvate kinase and glycolytic metabolism in three human glioma cell lines. 179 9

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

The presence of glycolytic enzymes and a GLUT-1-type glucose transporter in rod and cone outer segments was determined by enzyme activity assays, glucose uptake measurements, Western blotting, and immunofluorescence microscopy. Enzyme activities of six glycolytic enzymes including hexokinase, phosphofructokinase, aldolase, glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, pyruvate kinase, and lactate dehydrogenase, were found to be present in purified rod outer segment (ROS) preparations. Immunofluorescence microscopy of bovine and chicken retina sections labeled with monoclonal antibodies against glyceraldehyde-3-phosphate dehydrogenase, phosphoglycerate kinase, and lactate dehydrogenase have confirmed that these enzymes are present in rod and cone outer segments and not simply contaminants from the inner segments or other cells. Rod outer segments were also found to contain glucose transport activity as detected by 3-O-[14C]methylglucose uptake and exchange. The glucose transporter had a Km of 6.3 mM and a Vmax of 0.15 nmol of 3-O-methylglucose/s/mg of ROS membrane protein for net uptake and a Km of 29 mM and a Vmax of 1.06 nmol of 3-O-methylglucose/s/mg of ROS membrane protein for equilibrium exchange. These Km values for net uptake and equilibrium exchange are similar to values obtained for human red blood cells and are characteristic of GLUT-1-type glucose transporter. The transport was inhibited by both cytochalasin B and phloretin. Western blot analysis and immunofluorescence microscopy using type-specific glucose transporter antibodies indicated that both rod and cone outer segment plasma membranes have a GLUT-1 glucose transporter of Mr 45K as found in red blood cells and brain microsomal membranes. Solid-phase radioimmune competitive inhibition studies indicated that rod outer segment plasma membranes contained 15% the number of glucose transporters found in human red blood cell membranes and had an estimated density of 400 glucose transporter per micron2 of plasma membrane. These studies support the view that outer segments can generate energy in the form of ATP and GTP by anaerobic glycolysis to supply at least some of the energy requirements for phototransduction and other metabolic processes.
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PMID:Glycolytic enzymes and a GLUT-1 glucose transporter in the outer segments of rod and cone photoreceptor cells. 193 98

The alterations in specific activity and/or isozyme pattern of hexokinase, phosphofructokinase, aldolase, enolase, pyruvate kinase and glucose-6-phosphate dehydrogenase were studied in the tissue specimens of 26 patients with lipoblastic tumors and 28 patients with tumors of neurogenic origin. Although the biochemical data demonstrated that the activities of most enzymes studied were elevated in the specimens of the malignant tumors, only the differences in activity of hexokinase, pyruvate kinase and glucose-6-phosphate dehydrogenase measured between benign and malignant neurogenic tumors were significant. In malignant tumors, especially those of neurogenic origin, the isozyme pattern of pyruvate kinase showed a shift towards K-type subunits.
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PMID:Activity of glycolytic enzymes and glucose-6-phosphate dehydrogenase in lipoblastic and neurogenic proliferations. 216 88

It is generally recognized that the activities of some of the red cell enzymes decline as the cell ages. However, there is still a controversy regarding the rate at which this aging occurs. In the present study we applied newly developed technology for the specific isolation of maturing reticulocytes/erythrocytes for a more comprehensive study of in vivo aging of red cell enzymes in rabbits. Anemia was induced by repeated phlebotomy, and reticulocyte-rich erythrocytes were labeled with N-hydroxy succinimido-biotin and then transfused into a normal rabbit. These biotinylated cells were isolated at various time points by their affinity for an avidin support, and the enzymatic activity of 19 red cell enzymes was measured. We observed a biphasic pattern of decay for the activity of six age-dependent enzymes--aldolase, glutamate-oxaloacetate transaminase, glucose 6-phosphate dehydrogenase, hexokinase, pyrimidine 5'-nucleotidase, and pyruvate kinase.
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PMID:In vivo aging of red cell enzymes: study of biotinylated red blood cells in rabbits. 231 8

We have studied the effect of T3 administration (50 micrograms/Kg/day) on the phenotype expression of several glucose-metabolizing enzymes (hexokinase, HK, glucose-6-phosphate dehydrogenase, G6P-DH, aldolase, ALD, phosphofructokinase, PFK, lactate dehydrogenase, LDH) in the different myocardial layers of the left ventricle wall. In the control rats, most of these enzyme activities are uniformly distributed across the left ventricle wall, G6P-DH being the only exception. In the rats given T3 for 14 days, the mean levels of PFK, HK and ALD activities increased significantly. With regard to the transmural distribution patterns, that of PFK was unchanged, unlike those of HK and ALD which exhibited their maximum increase in activity in the midmyocardium or in the mid- and subepicardial myocardium. With LDH, a significant increase in activity was found in the subepicardial layers which escaped detection on the whole homogenate. It is concluded that the administration of thyroid hormone has different effects on enzyme phenotype expression of cardiomyocytes in different regions of the cardiac wall.
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PMID:Regional differences in the response of cardiac cells to triiodothyronine administration across the left ventricle free wall of rat heart. 231 6


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