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Query: EC:1.1.1.49 (glucose-6-phosphate dehydrogenase)
 7,794 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

A nicotinamide adenine dinucleotide phosphate dependent glucose 6-phosphate dehydrogenase (G6PD), belonging to type I of Kamada and Hori's classification, is present on the zymograms of newly emerged males of Musca domestica. It is capable of undergoing tryptic degradation and being thus transformed into a different active enzymatic form, with some of its catalytic properties unchanged, but with different electrophoretic mobility. We show in this paper that this specific G6PD form of gut origin in M. domestica is not a tissue-specific enzyme, but rather a product of hydrolytic degradation by gut proteinases which act during the process of homogenization. Besides, the G6PD of type I in the housefly is shown to be sensitive to the "storage effect" and to protection by mercaptoethanol, contrary to its hydrolytic gut form which is not sensitive to these processes. In this connection, we discuss the possible reasons for these differences in behavior.
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PMID:The in vitro conversion of a specific molecular form of glucose 6-phosphate dehydrogenase from Musca domestica L. 3 99

A rapid, high-yield method for purification of 6-phosphogluconate dehydrogenase from Escherichia coli K-12 is described. Sonic extracts prepared from heat-induced cultures of strain RW184, doubly lysogenic for the specialized transducing bacteriophage lambdacI857St68h80dgndhis and bearing a deletion of the gene for glucose 6-phosphate dehydrogenase, contained levels of 6-phosphogluconate dehydrogenase 15- to 20-fold higher than cultures of wild-type cells. Affinity chromatography on blue dextran-Sepharose with batchwise elution with 1 mM nicotinamide adenine dinucleotide phosphate affected a further 10-fold purification. Enzyme prepared in this manner was homogeneous according to electrophoresis on sodium dodecyl sulfate-polyacrylamide gels and immunoelectrophoresis using antiserum directed against it. Fructose 1,6-diphosphate is an inhibitor of enzyme activity.
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PMID:Combined use of strain construction and affinity chromatography in the rapid, high-yield purification of 6-phosphogluconate dehydrogenase from Escherichia coli. 3 19

Kinetic studies on the inhibition of the activity of glucose-6-phosphate dehydrogenase with mercuric chloride (MC) and methylmercuric chloride (MMC) have revealed that MC inhibited the enzyme non-competitively, while MMC inhibited it competitively. The Km value was 5.26 X 10(-5) M for glucose-6-phosphate and Ki value of MC was 2.17 X 10(-5) M, while that of MMC was 4.35 X 10(-3) M. The strong complex formation of nicotinamide adenine dinucleotide phosphate (NADP) or amino acids (cysteine, cystine, histidine, tryptophan or tyrosine) with MC was demonstrated in the presence of phosphate buffer as compared with that of MMC in the same buffer.
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PMID:Inhibitory actions of mercury compounds against glucose-6-phosphate dehydrogenase from yeast. 4 Nov 4

The adenosone 5'-triphosphate-insensitive glucose 6-phosphate dehydrogenase from Pseudomonas cepacia has been found to be strongly inhibited by long-chain fatty acids and their acyl coenzyme A esters, suggesting that an important role of this isoenzyme might be to provide reduced nicotinamide adenine dinucleotide phosphate for reductive steps in fatty acid synthesis. The enzyme, which has been redesignated the fatty acid-sensitive glucose 6-phosphate dehydrogenase, has been purified to homogeneity using affinity chromatography with nicotinamide adenine dinulceotide phosphate-substituted Sepharose as a key step in the purification. The purified preparations were used to study the immunological properties and subunit composition of the enzyme and its relationship to the adenosine 5'-triphosphate-sensitive glucose 6-phosphate dehydrogenase present in extracts of P. cepacia. Although both enzymes were found to be composed of similar size subunits of about 60,000 daltons, immunological studies failed to demonstrate any antigenic similarity between them. Studies of the sedimentation behavior of the fatty acid-sensitive enzyme in sucrose gradients indicated that its apparent molecular weight is increased in the presence of glucose 6-phosphate and suggest that it may exist in an aggregated state in vivo. Palmitoyl coenzyme A, which strongly inhibited the enzyme, failed to influence its sedimentation behavior.
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PMID:Characterization of the fatty acid-sensitive glucose 6-phosphate dehydrogenase from Pseudomonas cepacia. 7 65

Mutant strains of Pseudomonas aeruginosa PAO were isolated on the basis of their inability to utilize mannitol as sole carbon source for growth. Four linkage groups (I through IV) among these mutant strains were resolved by two-factor crosses using the general transducing phage F116, and the strains appeared to contain point mutations as evidenced by ability to give rise to spontaneous revertants with wild phenotype on mannitol minimal agar. Group I strains were affected only in ability to grow on mannitol; all were deficient in inducible mannitol dehydrogenase activity, and all but one were deficient in inducible mannitol transport activity. Fructokinase was induced in group I strains and in wild-type bacteria during growth in the presence of mannitol but not fructose, indicating the presence of a pathway specific for endogenously generated fructose. Cells grown on fructose contained phosphoenolpyruvate:fructose-1-phosphotransferase activity, and mannitol-grown cells contained a lower level of this activity. Group II mutants were deficient in constitutive phosphoglucoisomerase, failed to grow on mannitol, grew very slowly on glycerol and fructose, but grew normally on glucose and gluconate. Group III strains were deficient in both nicotinamide adenine dinucleotide- and nicotinamide adenine dinucleotide phosphate-linked glucose-6-phosphate dehydrogenase activities that reside in a single enzyme species. 6-Phosphogluconate appeared to be the inductive effector for this enzyme, which was not required for aerobic growth on glucose or gluconate. A single mannitol-negative mutant in group IV also failed to grow on glycerol and glucose, but no biochemical lesion was identified.
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PMID:Mannitol and fructose catabolic pathways of Pseudomonas aeruginosa carbohydrate-negative mutants and pleiotropic effects of certain enzyme deficiencies. 14 1

The activity of glucose-6-phosphate dehydrogenase (EC 1.1.1.44), transketolase (EC 1.1.1.44), transketolase (EC 1.1.1.49), 6-phosphogluconate dehydrogenase (EC 2.2.1.1.) and also the thiaminediphosphate (TDP) content were investigated on the 8th day after adrenalectomy. With compensated sodium dysbalance the removal of suprarenals is shown not to change the activity of dehydrogenases, but it does lower the transketolase activity and the TDP level. A seven-fold administration to adrenalectomized animals of nicotinic acid, thiamine or a simple injection of nicotinamide normalize the transketolase activity through raising the TDP level. The fact of the reduced transketolase activity in the kidneys in hypocorticotism being due to deficiency of the co-enzyme is also proved by the presence of the TDP-effect in vitro.
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PMID:[Effect of vitamins PP and B1 on pentosephosphate pathway enzymatic activity in the kidneys of adrenalectomized rats]. 14 33

Cytochalasin B (CB) is known to regulate the movement of intracellular microfilaments system. In this experiment, the effect of CB on the intraleukocytic bactericidal activity was first studied and concluded that CB inhibited the intracellular bactericidal activity remarkably. Addition of CB resulted in increased nitroblue tetrazolium (NBT)-dye reduction, while the specific activities of glucose-6-phosphate dehydrogenase (G-6-PD) and reduced nicotinamide-adenine dinucleotide phosphate (NADPH) oxidase of CB-treated neutrophils exhibited within the normal range. But the uptake of Glucose-1-14C or -6-14C was markedly inhibited by CB treatment. However, the following substances inhibited NBT-dye reduction in decreasing order: cyclic adenosine 3', 5'-monophosphate (cAMP), N6-O2' dibutyryl cyclic adenosine 3', 5'-monophosphate (DBcAMP), prostaglandin F2alpha (PGF2alpha) and prostaglandin E1 (PGE1). These drugs also decreased hexose monophosphate shunt (HMS) enzyme activities. Addition of CB and DBcAMP decreased the intracellular bactericidal activity of neutrophils. But CB had no effect on intracellular levels of cAMP. From the results obtained, it is likely that intracellular bactericidal phenomena of human neutrophils are controlled by cyclic AMP cascades and by the microfilaments system, separately.
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PMID:Effects of cytochalasin B and dibutyryl cyclic AMP on intraleukocytic bactericidal activity. 18 Mar 16

A facile proton magnetic resonance technique is described for the determination of the coenzyme stereospecificity during hydride transfer reactions catalyzed by pyridine nucleotide dependent oxidoreductases. The reliability of this technique was demonstrated by examining the coenzyme stereospecificity of lactate, malate, and 3-phosphoglycerate dehydrogenases, which are known to be A-stereospecific enzymes, as well as triosephosphate and octopine dehydrogenases, which are known to be B-stereospecific enzymes. Furthermore, by applying this technique, it was shown that the previously unstudied enzymes D-beta-hydroxybutyrate and 4-aminobutanal dehydrogenases are B- and A-stereospecific enzymes, respectively. In addition, the nicotinamide adenine dinucleotide linked reaction of glucose-6-phosphate dehydrogenase from Leuconostoc mesenteroides was found to be B stereospecific, like the reaction of the nicotinamide adenine dinucleotide phosphate linked yeast enzyme.
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PMID:Determination of the hydride transfer stereospecificity of nicotinamide adenine dinucleotide linked oxidoreductases by proton magnetic resonance. 18 97

Some considerations concerning the detailed mechanism of negative cooperativity in GPD are proposed. The hypothesis represents a modification of the sequential model (Koshland et al.) taking into account last experimental data about the binding of NAD analogs and fragments. Two main facts have been used as a basis for the model: 1. Neither ADP-ribose nor nicotinamide mononucleotide (NMN) fragments of NAD show negative cooperative binding to GPD. 2. Neither modifications of adenine and nicotinamide part of NAD (epsilon-NAD, hypoxantine-NAD, oxidized and reduced-NAD) nor enzyme modifications by various reagents acting in the catalytic site affect considerably the cooperativity of coenzyme binding although the affinity between enzyme and coenzyme (analogs) substantially changes depending on the nature of modification. Probably the structural integrity of a coenzyme molecule is necessary for the cooperative binding to GPD. On the other hand, numerous modification studies can be interpreted as proving the absence of direct participation of adenine and nicotinamide rings in the mechanism of negative interactions between NAD-binding sites. It appears reasonable to assume that direct or indirect interactions of riboseAD and pyrophosphate groups of NAD with the "loop" of adjacent subunit might be necessary for the tight coenzyme binding to the first active site of the r-dimer(s) symmetric across the R-axis. After the tight binding of the first NAD molecule on r-dimer with the "loop" participation, the symmetrical movement of second "loop" might be highly restricted. It was postulated that only asymmetric conformational transition is possible in contact areas between subunits across the R-axis. Such asymmetric rearrangement can explain the nonequivalent binding of NAD to a prior symmetric dimmer(s).
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PMID:[Possible nature of negative cooperation in D-glyceraldehyde-3-phosphate dehydrogenase]. 22 1

Multiple molecular forms of glucose-6-phosphate dehydrogenase (G6PD) in normal, preneoplastic, and neoplastic mammary tissues were separated by polyacrylamide gel electrophoresis and identified by specific straining for enzyme activity. Mammary tissue from lactating BALB/c mice showed considerable amounts (up to 50%) of a slower-migrating G6PD species, G6PD-III, which was essentially absent from glands of pregnant mice, preneoplastic nodules, and mammary carcinomas. All tissues possessed a faster-migrating species, G6PD-II, which accounted for up to 85% of the total G6PD in the glands of pregnant mice. A third species, G6PD-I, migrating more rapidly than G6PD-II, was found in both abnormal tissues (preneoplastic and neoplastic) and accounted for up to 35% of the total enzymatic activity. G6PD-I was present in moderate amounts (less than 15%) in glands from pregnant mice and was essentially absent from the lactating gland (approximately 5%). The addition of dithiothreitol did not alter the measurable G6PD activity but did increase the relative activity of G6PD-II or G6PD-I, as judged by the intensity of the bands on the gels. Mild oxidation (stirring overnight at 4 degrees in air) resulted in a loss of G6PD activity, but preparations had greater amounts of G6PD-III; presence of dithiothreitol during aeration partially prevented loss of G6PD activity and largely prvented the appearance of G6PD-III. Molecular-weight estimations with preparations from lactating mice yielded a value of 118,000 for G6PD-II and 260,000 for G6PD-III, suggesting a monomer and dimer, respectively. The addition of nicotinamide adenine dinucleotide phosphate stabilized G6PD activity by preventing heat inactivation at 47 degrees; nicotinamide adenine dinucleotide phosphate did not alter the pattern of species present. The data from heat inactivation studies suggest that G6PD-III (dimer) was the more stable species. The addition of nicotinamide adenine dinucleotide phosphate to samples after oxidation in the absence of dithiothreitol (about 70% loss of activity) resulted in no change in patterns and in recovery of full G6PD activity during heating at 47 degrees. A potential relationship between glutathione reductase activity and the pattern of G6PD species observed in the various tissues is noted.
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PMID:Multiple molecular forms of glucose-6-phosphate dehydrogenase in normal, preneoplastic, and neoplastic mammary tissues of mice. 23 37


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