Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:1.1.1.49 (glucose-6-phosphate dehydrogenase)
 7,794 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

An ultramicrochemical technique has been adapted to the evolution of enzyme profiles within individual human mammary tumors. Tandem observation of adjacent stained and lyophilized sections permitted dissection of microgram quantities of freeze-dried material within confirmed regions of malignancy. Enzymes frequently monitored to examine glycolytic, respiratory, and metastatic capacity were microanalyzed successfully: lactic dehydrogenase (LDH), phosphoglucose isomerase (PGI), malate dehydrogenase (MDH), acid phosphatase (AP), aldolase (ALD), glucose-6-phosphate dehydrogenase (G6PDH), pyruvate kinase (PK), alpha-glycerophosphate dehydrogenase (alpha-GOPDH), hexokinase (HK), and phosphofructokinase (PRK). All enzyme activities were higher in infiltrating ductal carcinomas than in fibroadenomas. Extracts of tumor cells mixed in varying proportions with brain or muscle extracts of rat evidenced no modification of expected activity. The technical adaptation described provided a sensitive methodology to resolve problems of relication, profile analysis, sample quantity, and selectivity within heterogeneous tissues.
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PMID:Application of a microchemical technique to the elucidation of enzyme activity profiles within single human mammary tumors. 20 41

The denaturation of eight purified yeast enzymes, glucose-6-phosphate dehydrogenase, 6-phosphogluconate dehydrogenase, glyceraldehyde-3-phosphate dehydrogenase, 3-phosphoglycerate kinase, alcohol dehydrogenase, beta-fructosidase, hexokinase and glucose-6-phosphate isomerase, promoted under controlled conditions by the free fatty acids myristic and oleic, is selective. Glucose-6-phosphate dehydrogenase (D-glucose-6-phosphate:NADP+ 1 oxidoreductase, EC 1.1.1.49) is extremely sensitive to destabilization and was studied in greater detail. Results show that chain length and degree of unsaturation of fatty acids are important to their destabilizing effect, and that ligands of the enzyme can afford protection. The denaturation process results in more than one altered form. These results can be viewed in the perspective of the possibility that amphipathic substances, and in particular free fatty acids, may play a role for enzyme degradation in vivo, by initiating steps of selective denaturation.
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PMID:Selective denaturation of several yeast enzymes by free fatty acids. 35 87

The Clarke-Carbon clone bank carrying ColE1-Escherichia coli DNA has been screened by conjugation for complementation of glycolysis and hexose monophosphate shunt mutations. Plasmids were identified for phosphofructokinase (pfkA), triose phosphate isomerase (tpi), phosphoglucose isomerase (pgi), glucose-6-phosphate dehydrogenase (zwf), gluconate-6-phosphate dehydrogenase (gnd), enolase (eno), phosphoglycerate kinase (pgk), and fructose-1,6-P2 aldolase (fda). Enzyme levels for the plasmid-carried gene ranged, for the various plasmids, from 4- to 25-fold the normal level.
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PMID:ColE1 hybrid plasmids for Escherichia coli genes of glycolysis and the hexose monophosphate shunt. 36 27

Results are presented on 147 individuals from northern Nigeria who were tested for the red cell antigens A, A1, B, H, M, N, S, s, He, P1, C, D, Du, E, c, e, Ce, v, Lua, Jka (some for Jkb), Lua, K, Jsa (some for Jsb), Kpa, Rd, Fya and Fyb, and for variants of the serum proteins haptoglobin and transferrin and of the red cell enzymes acid phosphatase, phosphoglucomutase, glucose-6-phosphate dehydrogenase, adenylate kinase, adenosine deaminase, phosphohexose isomerase and lactate dehydrogenase. The results found are of interest as they are among the very few published for this area of Nigeria, but they show little that is unexpected for people living in this region.
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PMID:The inherited blood factors of some Northern Nigerians. 46 76

A method is described for the measurement of enzyme activity under xeric conditions. The reaction mixtures had water contents ranging between 0.1 and 0.6g/g of reaction mixture. For glucose 6-phosphate dehydrogenase, hexokinase and fumarase, enzyme activity became detectable (about 0.05% of the fully hydrated rate) when the water content was about 0.2g/g of reaction mixture, and for phosphoglucose isomerase, around 0.15g/g of reaction mixture. With the water content raised to 0.3g/g of reaction mixture the reaction rates were only increased to 0.1-3% of the fully hydrated rate. When the combined rates for phosphoglucose isomerase and glucose 6-phosphate dehydrogenase were measured, reasonable agreement was found between the experimental data and those calculated from the individual experimentally determined rates on the assumption that diffusion was not further limiting. A method was devised for measuring the diffusion coefficients of low-molecular-weight substances in solutions having low water contents. The diffusion coefficients of riboflavin in sorbitol solution decreased by about 100-fold when the water content of the latter was reduced from 3 to 0.25g/g of sorbitol. It is concluded that to detect enzyme activity a certain minimal amount of water is required and that above this minimum the rate is still restricted by diffusion limitation. The relevance of the results to the physical state of water in reaction mixtures and to metabolism in seeds and spores in xeric conditions is discussed.
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PMID:The effect of restricted hydration on the rate of reaction of glucose 6-phosphate dehydrogenase, phosphoglucose isomerase, hexokinase and fumarase. 47 53

Two chemostat methods for studying the immobilized enzyme kinetics are presented. The methods are applied to glucose-6-phosphate isomerase immobilized within a proteic membrane. The first method is based on the steady state behavior of a Continuously Stirred Tank Reactor (C.S.T.R.) and the second one on a diffusion-reaction process. The apparent equilibrium ratio between glucose 6-phosphate and fructose 6-phosphate is measured for the immobilized enzyme system. No modification is observed with a monoenzyme membrane. In the presence of a glucose-6-phosphate dehydrogenase activity the product of the first reaction is trapped by the second one and due to the local intramembrane concentrations an apparent modification of the equilibrium ratio is observed. The apparent modification is studied with the bienzyme membrane as a function of the concentration of NADP co-substrate of the second enzyme. A "Michaelian" relationship is observed.
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PMID:Kinetic studies dealing with immobilized reversible enzyme system. Experimental evidence for shift of apparent equilibrium constant within bienzyme system. 55 87

Phenotype and gene frequencies are presented for eight polymorphic systems among the Nubians of South Egypt, namely, acid phosphatase, glucose-6-phosphate dehydrogenase, adenylate kinase, 6-phosphogluconate dehydrogenase, esterase D, phosphoglucomutase I, peptidase A, and haptoglobin. Eleven systems, namely, albumin, ceruloplasmin, hemoglobin, lactate dehydrogenase, isocitrate dehydrogenase, phosphohexose isomerase, malate dehydrogenase, peptidase B and C, phosphoglucomutase II, and transferrin were found to be monomorphic. A single electrophoretic variant of phosphohexose isomerase were observed.
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PMID:The Nubians of Kom Ombo: serum and red cell protein types. 61 20

The ratios of some key enzymatic activities of carbohydrate metabolism have been measured in human tumor cytosols. The activities of whole hexokinase (low Km, EC 2.7.1.1 and high Km, EC 2.7.1.2), 6-phosphogluconate dehydrogenase (EC 1.1.1.43), glucose-6-phosphate dehydrogenase (EC 1.1.1.49) and glucose-6-phosphate isomerase (EC 5.3.1.9) change according to a biochemical pattern coherent with cell growth requirements. 6-phosphogluconate dehydrogenase activity was in each sample tested higher than glucose-6-phosphate dehydrogenase activity; this indicates that 6-phosphogluconate, a powerful inhibitor of glucose-6-phosphate isomerase, is unlikely to accumulate and inhibit this enzyme and glucose-6-phosphate channelling into glycolysis.
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PMID:6-phosphogluconate dehydrogenase, glucose-6-phosphate dehydrogenase, glucose-6-phosphate isomerase, and hexokinase activity ratios in some human tumor cytosols. 74 21

A patient with combined deficiency of erythrocyte glucose phosphate isomerase (GPI) and glucose-6-phosphate dehydrogenase (G6PD) is presented. The propositus has persistent unconjugated hyperbilirubinemia. One of his two brothers exhibits the same rare enzymatic defect, but without any clinical symptoms. The electrophoretic pattern of GPI showed GPI type 1. There seems to be a correlation between the unconjugated hyperbilirubinemia and the combined enzymopathy in our patient.
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PMID:Combined glucose phosphate isomerase and glucose-6-phosphate dehydrogenase deficiency of erythrocytes. 75 May 48

Alpha-D-Glucose is known to exert more marked insulinotropic action than B-D-glucose. Both anomers are phosphorylated at the same rate by rat islet homogenates. The islet glucose-6-phosphate dehydrogenase displays a preferential affinity towards beta-D-glucose-6-phosphate, and this coincides with a higher sorbitol content in the islets exposed to beta-D-glucose. On the contrary, the islet phosphoglucose isomerase is stereospecific for alpha-D-glucose 6-phosphate and, hence, the concentration of glucose 6-phosphate is lower and that of the alpha-anomer to lactate and CO2 is also higher than that of beta-D-glucose. This increased glycolytic flux is associated with a more marked inhibitory action on 14Ca efflux, a more pronounced stimulation of 45Ca net uptake and a higher rate of insulin release in the islets exposed to alpha-D-glucose. The more marked insulinotropic action of alpha- as a distinct from beta-D-glucose is thus compatible with the view that glycolysis represents the key component of the sensor device through which glucose is identified in the pancreatic B-cell as a stimulus for insulin release.
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PMID:Stimulus-secretion coupling of glucose-induced insulin release. Metabolism of alpha- and beta-D-glucose in isolated islets. 78 87


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