Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UNIPROT:Q9UMR3 (NMR)
 150,598 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Physico-chemical, spectroscopic (UV, IR, NMR, mass), chromatographic (GLC, TLC) properties and synthesis of 1,3-bis(2-ethylhexyl)-5-amino-5-methyl-hexahydropyrimidine (hexetidine) are reported and discussed. Moreover, the difference between commercial and purified hexetidine is demonstrated.
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PMID:[Analytical profile of purified hexetidine (author's transl)]. 0 83

Phosphorus nuclear magnetic resonance (31P NMR) spectroscopy was used to estimate the percent of 2,3-diphosphoglycerate and ATP bound to hemoglobin in intact human erythrocytes at 37 degrees C. Binding was assessed by comparing the chemical shifts (delta) of 2,3-diphosphoglycerate and of ATP observed in intact cells with the delta values of these organic phosphates determined in model solutions closely simulating intracellular conditions, in which percent binding was directly evaluated by membrane ultrafiltration. The results showed that the percent of bound 2,3-diphosphoglycerate in intact cells varied with pH, the state of oxygenation, and 2,3-diphosphoglycerate concentration. The values ranged from 33% in cells incubated with glucose in air at an intracellular pH of 7.2 to 100% in cells incubated with inosine in N2 at a pH of 6.75. At the same 2,3-diphosphoglycerate concentration, a greater percentage of the compound appeared to be bound in erythrocytes than in the closely simulated model system. ATP was not significantly bound to hemoglobin under any condition examined, but appeared to be strongly complexed to Mg2+ inside the erythrocyte. The binding percentages for both 2,3-diphosphoglycerate and ATP in intact cells estimated by 31P NMR spectroscopy were lower than those calculated by others from individual association constants determined for the binding of different ligands to hemoglobin.
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PMID:Organic phosphate binding to hemoglobin in intact human erythrocytes determined by 31P nuclear magnetic resonance spectroscopy. 1 55

High-resolution phosphorus-31 nuclear magnetic resonance (31P NMR) spectra of wild-type and mutant strains of Saccharomyces cerevisiae were observed at a frequency of 145.7 MHz. Levels of various phosphorus metabolites were investigated upon addition of glucose under both aerobic and anaerobic conditions. Three mutant strains were isolated and their biochemical defects characterized: pfk lacked phosphofructokinase activity; pgi lacked phosphoglucose isomerase activity; and cif had no glucose catabolite repression of the fructose bisphosphatase activity. Each mutant strain was found to accumulate characteristic sugar phosphates when glucose was added to the cell suspension. In the case of the phosphofructokinase deficient mutant, the appearance of a pentose shunt metabolite was observed. 31P NMR peak assignments were made by a pH titration of the acid extract of the cells. Separate signals for terminal, penultimate, and central phosphorus atoms in intracellular polyphosphates allowed the estimation of their average molecular weight. Signals for glycero(3)phosphochline, glycero(3)phosphoserine, and glycero(3) phosphoethanolamine as well as three types of nucleotide diphosphate sugars could be observed. The intracellular pH in resting and anaerobic cells was in the range 6.5--6.8 and the level of adenosine 5'-triphosphate (ATP) low. Upon introduction of oxygen, the ATP level increased considerably and the intracellular pH reached a value of pH 7.2--7.3, irrespective of the external medium pH, indicating active proton transport in these cells. A new peak representing the inorganic phosphate of one of the cellular organelles, whose pH differed from the cytoplasmic pH, could be detected under appropriate conditions.
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PMID:Phosphorus-31 nuclear magnetic resonance studies of wild-type and glycolytic pathway mutants of Saccharomyces cerevisiae. 4 May 90

Anaerobic glycolysis in Saccharomyces cerevisiae has been studied by 13C NMR at 90.5 MHz. [1-13c]Glucose and [6-13C]glucose were fed to suspensions of yeast cells. Time courses for concentration changes of the starting material, of courses for concentration changes of the starting material, of the intermediate fructose 1,6-bisphosphate (Fru-P2), and of the end products, ethanol and glycerol, have been followed with 1-min time resolution. The glucose uptake was well fitted by a Michaelis-Menten model, assuming competition of alpha- and beta-glucose for the same site. The Km for the uptake was found to be 10 mM for beta-glucose and 5 mM for alpha-glucose. The concentration of Fru-P2 showed an initial oscillation before it reached a co,stant level. The 13C label, introduced only as [-13C]- or [6-13C]glucose, was observed in Fru-P2 in both the C1 and C6 positions, simultaneously. From the relative intensities of the C1 Fru-P2 and C6 Fru-P2 peaks in the presence of [1-13C]- and [6-13C]glucose, in vivo kinetic information was obtained about the aldolase-triosephosphate isomerase triangle. We found that under the conditions of these experiments the ratios of backward to forward velocities through aldolase and triosephosphate isomerase were 0.9 +/- 0.1 and 0.8 +/- 1, respectively, indicating they were close to equilibrium.
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PMID:13C nuclear magnetic resonance studies of anaerobic glycolysis in suspensions of yeast cells. 4 10

The conversion of D,L-alpha-13C-histidine to similarly labeled alpha-13C histamine by bacterial and mammalian histidine decarboxylase was studied by 13C-NMR spectroscopy and GLC-mass spectrometry. The results obtained with the partially purified bacterial enzyme were in essentially perfect agreement with results obtained simultaneously with a standard radioisotopic method using carboxyl-labeled-14C-L-histidine. For a crude tissue preparation of the mammalian enzyme, the radioisotopic method indicated an activity three times that based on 13C-NMR measurement of alpha-13C-histamine. The difference in results was accountable in terms of additional 13C-NMR signals attributable to products other than histamine due in part to enzymatic degradation of the latter.
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PMID:Application of 13C-NMR spectroscopy to in vitro analysis of enzyme kinetics. 19 15

Bovine galactosyl transferase was found to utilize UDPglucose as a substrate and elicit disaccharide biosynthesis with glucose and N-acetylglucosamine as acceptors. The relative rate of glucosyl transferase with N-acetylglucosamine as acceptor was 0.3%, the rate for N-acetyllactosamine biosynthesis. This activity was also evidenced indirectly from NMR water proton relaxation experiments, and from Mn(II) ESR experiments. In direct experiments with radioactive UDPglucose, paper chromatography showed a product which migrated with cellobiose when glucose was the acceptor and a new, glucose-containing product which resulted when GlcNAc was the acceptor. Despite this marginally expanded specificity of the donor site, spin-label experiments with a covalently bound UDPgalactose analog reaffirmed the restrictive nature of the donor site against this non-glycosyl-like analog.
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PMID:Glucosyl transferase activity of bovine galactosyl transferase. 21 25

Natural-abundance (13)C NMR at 25.16 MHz has been used to study a 2.5% matrix of hyaluronic acid at various degrees of polymerization and at various ionic strengths. Peak assignment is facilitated by comparing proton-decoupled and off-resonance-decoupled spectra of a hyaluronidase-depolymerized matrix with spectra from relevant monosaccharides. In contrast to the spectrum following depolymerization, the spectrum for intact matrix has considerable broadening, particularly for peaks assigned to the N-acetylglucosamine moiety. This is most dramatic for the hydroxymethylene carbon. With the addition of Ca(2+) above 5 mM these broadened peaks narrow and approach the sharpness observed for the hyaluronidase digest. There is no shift in resonance peak positions. These changes are quantitatively less impressive if Na(+) is substituted for Ca(2+). The data suggest the existence of a considerable degree of order in regions of the matrix at physiological concentrations of Ca(2+). Within such a matrix the translational movement of lysine and glucose is enhanced relative to that in a matrix of agarose. Further addition of Ca(2+) abrogates not only matrix order, but the enhanced diffusivity as well.
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PMID:Effect of calcium on structure and function of a hyaluronic acid matrix: carbon-13 nuclear magnetic resonance analysis and the diffusional behavior of small solutes. 27 67

The gluconeogenic pathway from [2-13C]glycerol and [1,3-13C]glycerol has been followed in suspensions of isolated rat hepatocytes at 25 degrees C by 13C NMR at 90.5 MHz. The flow of label through the major pathway from glycerol to L-glycerol 3-phosphate and into glucose was followed in cells from control and triiodothyronine-treated rats. Treatment increased the rates of glucose formation and glycerol consumption 2-fold and decreased the alphaGP level to 40%. We calculate that approximately 60% of the flux is through the mitochondrial glycerol phosphate dehydrogenase in cells from triiodothyronine-treated rats, compared with approximately 15% in cells from the controls. Equal distribution of label between the trioses of glucose was obtained and, because the C3-C4 spin-spin coupling gives the distribution of labeled carbons in the same molecule, it was possible to measure the amount of triose from unlabeled fructose incorporated into the glucose labeled at carbons 1, 3, 4, and 6. About 10% of the hexoses had flowed through the pentose cycle and back into the hexose pathway in cells from fasted rats. From the distribution of label at glucose carbons not labeled via the major pathway and from the carbon spin-spin splitting patterns observed, we conclude that transketolase is reversible whereas transaldolase is essentially irreversible in the nonoxidative pentose branch.
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PMID:13C NMR studies of gluconeogenesis in rat liver cells: utilization of labeled glycerol by cells from euthyroid and hyperthyroid rats. 28 1

Time courses of 13C labeling from alanine and ethanol in perfused mouse livers have been followed by NMR. The enrichment at specific carbons of glucose, glutamate, glutamine, aspartate, acetate, acetoacetate, beta-hydroxybutyrate, and lactate has been measured. The specific labeling of glutamate in the presence of labeled alanine and labeled or unlabeled ethanol shows that, under these conditions, alanine enters the tricarboxylic acid cycle almost exclusively through pyruvate carboxylation, whereas ethanol is the exclusive source of acetyl-CoA. In the absence of ethanol, the alanine label flows through both paths. By comparing the scrambling of 13C between C3 and C2 of glutamate it is possible to estimate the mitochondrial fumarase activity; the C6-to-C5 ratios in glucose give the additional scrambling by cytosolic fumarase activity. In addition, the C6-to-C1 and C5-to-C2 ratios in glucose show that there is about 15% flux through the pentose cycle. Finally, the C4-to-C2 ratios in glutamine and glutamate are unequal at any time (the glutamine labels reflect the label distribution in glutamate measured 1 hr earlier), providing a method for studying flow through glutamine synthetase in situ.
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PMID:Effects of ethanol on alanine metabolism in perfused mouse liver studied by 13C NMR. 29

The reaction of water with isoflurophate to form diisopropylphosphate was examined and confirmed. Isolation of this decomposition product from an antiglaucoma drug formulation is described. A known reference compound was isolated from a commercial mixture also containing the monoisopropyl ester. The isolation, purification, and molecular spectroscopic and elemental confirmation of structure are described. IR, NMR, and mass spectra are included. Additionally, a GLC procedure and parameters used to identify diisopropylphosphate in a degraded peanut oil formulation of isofluorphate are reported. Reaction mixtures of this drug with water and sodium hydroxide were analyzed by GLC with the expected results.
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PMID:Separation and spectral properties of diisopropylphosphate, the major decomposition product of isoflurophate. 50 53


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