Binding of calcium, lead, and copper(II) cations to galactaric and 2,5-furandicarboxylic acids and to D-galacturonic acid and its derivatives

1986 ◽  
Vol 51 (5) ◽  
pp. 1150-1159 ◽  
Author(s):  
Rudolf Kohn ◽  
Ján Hirsch
Keyword(s):  
Galacturonic Acid ◽  
Uronic Acid ◽  
Indicator Method ◽  
Cu Complex ◽  
Carboxylate Groups ◽  
Counter Ions ◽  
Galactaric Acid ◽  
Furandicarboxylic Acid ◽  
The Difference ◽  
Calcium Lead

The binding of Ca2+, Pb2+, and Cu2+ ions to galactaric and 2,5-furandicarboxylic acids and of Pb2+ and Cu2+ ions to D-galacturonic acid, its α-methylglycoside, and (methyl-4-deoxy-α-D-galactopyranosid)uronic acid was evaluated in terms of the activity coefficients of the counter-ions and the degrees of their association with the carboxylate groups of the acids. The activity of Ca2+ ions was determined by the metallochromic indicator method with tetramethylmurexide, that of Pb2+ and Cu2+ ions, with ion specific electrodes. Galactaric acid bids 89.5% Ca2+ ions, practically all (99.9%) Pb2+ ions and nearly all (98.6% Cu2+ ions, mostly with the formation of insoluble salts. As little as 7.6% Ca2+, 34.0% Pb2+, and 23.9% Cu2+ were bound to 2,5-furandicarboxylic acid in the form of soluble complexes, and slightly more, 4.1% Ca2+, 43.9% Pb2+, and 38.0% Cu2+, to D-galacturonic acid. The difference in the degrees of binding to galactaric acid and 2,5-furandicarboxylic acid is due to the different flexibility of their molecular skeletons. The activities of Pb2+ and Cu2+ ions in solutions of salts of D-galacturonic acid and its derivatives indicate that the OH group at C(4) of D-galacturonic acid takes part in the complexation. For the Pb2+ complex, the OH group at C(1) of the unsubstituted acid in the β-anomeric form also seems to participate in the complexation; this is not the case with the similar Cu complex.

scholarly journals Transport of D-Glucose and 2-Fluorodeoxyglucose across the Blood-Brain Barrier in Humans

1996 ◽  
Vol 16 (4) ◽  
pp. 659-666 ◽  
Author(s):  
Steen G. Hasselbalch ◽  
Gitte M. Knudsen ◽  
Søren Holm ◽  
L. Pinborg Hageman ◽  
Brunella Capaldo ◽  
...  
Keyword(s):  
Blood Brain Barrier ◽  
Initial Distribution ◽  
Brain Barrier ◽  
Transport Parameters ◽  
Indicator Method ◽  
Blood Brain ◽  
The Difference ◽  
Regional Cerebral Glucose Metabolism ◽  
The Brain

The deoxyglucose method for calculation of regional cerebral glucose metabolism by PET using 18F-2-fluoro-2-deoxy-d-glucose (FDG) requires knowledge of the lumped constant, which corrects for differences in the blood–brain barrier (BBB) transport and phosphorylation of FDG and glucose. The BBB transport rates of FDG and glucose have not previously been determined in humans. In the present study these transport rates were measured with the intravenous double-indicator method in 24 healthy subjects during normoglycemia (5.2 ± 0.7 m M). Nine subjects were restudied during moderate hypoglycemia (3.4 ± 0.4 m M) and five subjects were studied once during hyperglycemia (15.0 ± 0.7 m M). The global ratio between the unidirectional clearances of FDG and glucose (K1*/K1) was similar in normoglycemia (1.48 ± 0.22), moderate hypoglycemia (1.41 ± 0.23), and hyperglycemia (1.44 ± 0.20). This ratio is comparable to what has been obtained in rats. We argue that the global ratio is constant throughout the brain and may be applied for the regional determination of LC. We also determined the transport parameters of the two hexoses from brain back to blood and, assuming symmetrical transport across the BBB, we found evidence of a larger initial distribution volume of FDG in brain (0.329 ± 0.236) as compared with that of glucose (0.162 ± 0.098, p < 0.005). The difference can be explained by the very short experimental time, in which FDG may distribute both intra- and extracellularly, whereas glucose remains in a volume comparable to the interstitial fluid of the brain.

scholarly journals Determination of the pKa of glucuronic acid and the carboxy groups of heparin by 13C-nuclear-magnetic-resonance spectroscopy

1991 ◽  
Vol 278 (3) ◽  
pp. 689-695 ◽  
Author(s):  
H M Wang ◽  
D Loganathan ◽  
R J Linhardt
Keyword(s):  
Uronic Acid ◽  
Model Compound ◽  
Molecular Size ◽  
Resonance Spectroscopy ◽  
Model Compounds ◽  
Pka Values ◽  
Carboxylate Groups ◽  
13C Nuclear Magnetic Resonance ◽  
Unambiguous Assignment

As part of our continuing studies on heparin, the present paper uses 13C-n.m.r. spectroscopy to examine the acidity of heparin's uronic acid carboxylate groups. Heparin contains three different uronic acids. In porcine mucosal heparin these account for approx. 91, 7 and 2 mol% of the total uronic acid residues. These are alpha-L-idopyranosyluronic acid 2-sulphate, beta-D-glucopyranosyluronic acid and alpha-L-idopyranosyluronic acid. The pKa values of their carboxylate groups were determined as 3.13 (using heparin), 2.79 (using heparin) and 3.0 (predicted by using model compounds) respectively. 18C-n.m.r. spectroscopy, performed at various pH values, provided a convenient method of simultaneously determining the pKa of multiple carboxylate groups, of similar acidity, within heparin D-Glucopyranosyluronic acid and heparin-derived di-, tetra- and hexa-saccharides were used as model compounds to determine pKa values of the different carboxy groups. The results suggested that molecular size had an effect on pKa. Unambiguous assignment of carboxy carbon resonances were accomplished through the use of two-dimensional n.m.r. spectroscopy. Finally, application of this method to the simplest model compound, D-glucopyranosyluronic acid, permitted the determination of the pKa of both its alpha- and beta-anomers.

Complexation of Actinides with Amide Derivatives of Oxydiacetic Acid

2005 ◽  
Vol 893 ◽  
Author(s):  
Linfeng Rao ◽  
Guoxin Tian
Keyword(s):  
Stability Constants ◽  
Structural Information ◽  
Lanthanide Ions ◽  
Carboxylate Groups ◽  
Amide Derivatives ◽  
Ether Oxygen ◽  
The Difference ◽  
Solid Compounds ◽  
The Stability ◽  
Oxydiacetic Acid

AbstractComplexation of Np(V), U(VI) and Nd(III) with dimethyl-3-oxa-glutaramic acid (DMOGA) and tetramethyl-3-oxa-glutaramide (TMOGA) was studied in comparison with the complexation with oxydiacetic acid (ODA). Stability constants and enthalpy of complexation were determined by potentiometry, spectrophotometry and calorimetry. Thermodynamic parameters, in conjunction with structural information of solid compounds, indicate that DMOGA and TMOGA form tridentate complexes with the ether-oxygen participating in bonding with actinide/lanthanide ions. The trends in the stability constants, enthalpy and entropy of complexation are discussed in terms of the difference in the hydration of the amide groups and carboxylate groups and the difference in the charge density of the metal ions.

USE OF LIQUID AMMONIA IN THE FRACTIONATION OF WHEAT STRAW HOLOCELLULOSE

1950 ◽  
Vol 28b (12) ◽  
pp. 753-761 ◽  
Author(s):  
C. T. Bishop ◽  
G. A. Adams
Keyword(s):  
Wheat Straw ◽  
Potassium Hydroxide ◽  
Galacturonic Acid ◽  
Uronic Acid ◽  
Room Temperature ◽  
Liquid Ammonia ◽  
Cold Water ◽  
Acid Anhydride ◽  
Acid Complex ◽  
Molar Ratios

Wheat straw holocellulose, after soaking in liquid ammonia for 36 hr. at room temperature, was fractionated by successive extractions with cold water, 0.5% sodium carbonate, 0.5% potassium hydroxide, and 2.2% potassium hydroxide. Pretreatment with liquid ammonia increased the material soluble in cold water from 3% to 20.2%. Hemicellulose fractions were precipitated from the extracts by ethanol. A complete analytical balance was obtained by estimating ash, pentosan, uronic acid anhydride, acetyl, and methoxyl contents of the original holocellulose, of each of the fractions and of the residue. Analyses of the isolated fractions showed some systematic differences, with pentosan contents increasing and uronic acid anhydride decreasing progressively in the alkali soluble fractions. D-xylose, L-arabinose, D-glucose, D-galactose, and hexuronic acid in approximate molar ratios of 40:7:2:1:4 were found in the hemicellulose fractions. The presence of the sugars was confirmed by isolation of crystalline derivatives. A uronic acid complex, resistant to hydrolysis, was isolated and the components shown to be D-xylose and a monomethoxyl galacturonic acid.

scholarly journals Effect of age on digestibility of starch in chickens with different growth rate

2011 ◽  
Vol 50 (No. 9) ◽  
pp. 411-415 ◽  
Author(s):  
J. Zelenka ◽  
Z. Čerešňáková
Keyword(s):  
Growth Rate ◽  
Starch Digestibility ◽  
Indicator Method ◽  
Average Value ◽  
Maize Type ◽  
High Starch ◽  
Ad Libitum ◽  
The Difference ◽  
Slow Growing ◽  
Effect Of Age

Digestibility of starch was examined in slow-growing cockerels of laying type (SG) and in fast-growing male chickens (FG) of broiler type fed ad libitum on a&nbsp;maize-type diet until Day 22 of age in one-day periods and from Day 22 to Day 100 in three-day periods. Digestibility was estimated using the chromic oxide indicator method. In SG chicks, starch digestibility rapidly increased within the first days of their lives and reached the value of 0.986 already on Day 4 of life. It was maintained on this level till the end of the experiment, which was finished at the age of 100 days. In FG chicks, which in comparison with SG birds consumed more than a double quantity of feed, high starch digestibility was observed as late as on Day 8. From Day 8 to Day 100 of age, starch digestibility slightly but highly significantly (P &lt; 0.01) decreased. The average value of digestibility was lower by 0.008 in broiler type chickens than in SG chickens at this time; nevertheless, digestibility was never below 0.96. The difference was highly significant (P&lt; 0.001). &nbsp; &nbsp;

Composite host lattices of 4,4′-sulfonyldibenzoate water/boric acid in two tetrapropylammonium inclusion compounds

2018 ◽  
Vol 74 (9) ◽  
pp. 1026-1031
Author(s):  
Xiangxiang Wu ◽  
Huahui Zeng ◽  
Yunxia Yang
Keyword(s):  
Boric Acid ◽  
Small Molecules ◽  
Crystal Structures ◽  
Inclusion Compounds ◽  
X Ray Diffraction ◽  
X Ray ◽  
Counter Ions ◽  
Proton Donors ◽  
The Difference ◽  
Host Lattices

Two novel inclusion compounds of 4,4′-sulfonyldibenzoate anions and tetrapropylammonium cations with different ancillary molecules of water and boric acid, namely bis(tetrapropylammonium) 4,4′-sulfonyldibenzoate dihydrate, 2C12H28N+·C14H8O6S2−·H2O (1), and bis(tetrapropylammonium) 4,4′-sulfonyldibenzoate bis(boric acid), 2C12H28N+·C14H8O6S2−·2H3BO3 (2), were prepared and characterized using single-crystal X-ray diffraction. In the two salts, the host 4,4′-sulfonyldibenzoic acid molecules, which are converted to the corresponding anions under basic conditions, can be regarded as proton acceptors which link different proton donors of the ancillary molecules of water or boric acid. In this way, an isolated hydrogen-bonded tetramer is constructed in salt 1 and a ribbon is constructed in salt 2. The tetramers and ribbons are then packed in a repeating manner to generate various host frameworks, and the tetrapropylammonium guest counter-ions are contained in the cavities of the host lattices to give the final stable crystal structures. In these two salts, although the host anion and guest cation are the same, the difference in the ancillary small molecules results in different structures, indicating the significance of ancillary molecules in the formation of crystal structures.

scholarly journals Tetraammonium μ-ethylenediaminetetraacetato-1κ3 O,N,O′:2κ3 O′′,N′,O′′′-bis[trioxidotungstate(VI)] tetrahydrate

IUCrData ◽  
2021 ◽  
Vol 6 (9) ◽  
Author(s):  
Lamine Yaffa ◽  
Sérigne Fallou Pouye ◽  
Daouda Ndoye ◽  
Waly Diallo ◽  
Mayoro Diop ◽  
...  
Keyword(s):  
Ethylenediaminetetraacetic Acid ◽  
Three Dimensional ◽  
Tungstic Acid ◽  
Central Metal Atom ◽  
Central Metal ◽  
Tungsten Atom ◽  
Carboxylate Groups ◽  
Carbon Carbon Bond ◽  
Counter Ions ◽  
Distorted Octahedral

The title compound, (NH4)4[W2(C10H12N2O8)O6]·4H2O, was obtained from a mixture of tungstic acid, ammonia and ethylenediaminetetraacetic acid (H4edta) in a 2:4:1 ratio. The anion of the complex contains two WO3 units and one bridging edta4− ligand. Each central metal atom is tridentately coordinated by nitrogen and two carboxylate groups of the edta4− ligand, together with the three oxido ligands, producing a distorted octahedral coordination environment around each tungsten atom. The center of the carbon–carbon bond of the ethylene bridge represents a crystallographic inversion center. The crystal structure consists of a three-dimensional supramolecular framework built up by the dinuclear cations, the ammonium counter-ions and the solvent water molecules via hydrogen bonds of the N—H...O and O—H...O type.

Binding of lead cations to oligogalacturonic acids

1982 ◽  
Vol 47 (12) ◽  
pp. 3424-3431 ◽  
Author(s):  
Rudolf Kohn
Keyword(s):  
Human Body ◽  
Calcium Ions ◽  
Galacturonic Acid ◽  
Uronic Acid ◽  
The Other ◽  
Carboxyl Groups ◽  
Polymeric Chain ◽  
Polymerization Degree ◽  
Strong Decrease ◽  
Nitrate Ions

The activity of Pb2+ ions in solutions of lead oligogalacturonates of polymerization degree DP 1 to 5 (starting concentration of the investigated solutions 3.00 mmol (COOPb0.5) l-1, the ionic strenght of the solution I = 0.01 mol l-1, electrolyte KNO3, was determined by lead specific ion electrodes. The activity aPb2+ is independent on the kind of anion in very diluted solutions of lead perchlorate and nitrate. Ions of lead become bound quite firmly even to the monomeric D-galacturonic acid (association degree of Pb2+ ions to carboxyl groups of uronic acid β = 0.43). The increase of polymerization degree is associated with a strong decrease of the lead oligogalacturonate solubilities on one hand, and increase of the bond strenght of the Pb2+ ions to these oligomers on the other. The association degree of Pb2+ ions to carboxyl groups of the pentamer (β = 0.96) almost reaches the value found for the polymeric chain of pectate molecule (D-galacturonan); here, the stoichiometric binding of Pb2+ to two carboxyl groups takes place with a great deal of probability. Lead has been found to bind highly preferentially to oligogalacturonates even in the presence of calcium ions. Results presented in this paper help to clear the mechanism of elimination of lead from the human body through pectin and its oligomeric fragments.

Comparison and Assessment of the Difference in Total Dietary Fiber in Cooked Dried Legumes as Determined by Five Methods

1994 ◽  
Vol 77 (5) ◽  
pp. 1197-1202 ◽  
Author(s):  
Roger Mongeau ◽  
René Brassard
Keyword(s):  
Dimethyl Sulfoxide ◽  
Dietary Fiber ◽  
Uronic Acid ◽  
Chromatographic Method ◽  
Dry Weight ◽  
Porcine Pancreas ◽  
Total Dietary Fiber ◽  
Kidney Beans ◽  
The Difference ◽  
Gas Chromatographic Method

Abstract Dried beans (kidney and great northern) and dried peas (chick, green, and yellow) were cooked according to package instructions. Total dietary fiber (TDF) was measured by the Mongeau (AOAC 992.16), Prosky (AOAC 985.29), and Lee (AOAC 991.43) methods (A, B, and C, respectively). Non-starch polysaccharides (NSP) were measured by the Englyst gas-chromatographic method that included dimethyl sulfoxide treatment, and the lignin measured separately was added to NSP (method D). TDF was also measured by the Li method (E). TDF values ranged from 7 to 48 g/100 g dry weight. Methods B and C gave similar TDF values, which were higher than those from other methods. For kidney beans I, TDF values by methods B and C were up to 2.5 times higher because of the inclusion of starch. The fiber residues from methods A and C contained the same amounts of arabinose, xylose, mannose, galactose, and uronic acid, but glucose was 4 times higher in residue C than in residue A. When α-amylase from porcine pancreas was incorporated in methods B or C for 5 samples, the discrepancies among methods A, B, and C were reduced by 60-98%.

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