Preparation of Water-soluble Polyuronic Acids and their Calcium Salts, and the Determination of Calcium Ion Activity in Relation to the Degree of Polymerization.

Köhn, R.; Larsen, Brent

doi:10.3891/acta.chem.scand.26-2455

Cited by 99 publications

(51 citation statements)

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“…The same range of limit was obtained by Kohn and Larsen [71,72] who worked on different oligouronates.…”

Section: Polyelectrolyte Characteristicssupporting

confidence: 63%

Polyelectrolyte properties of a plant and animal polysaccharide

Rinaudo¹

2009

Struct Chem

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The principal properties of polyelectrolytes in aqueous solution are reviewed; experimental data obtained about polysaccharides in our laboratory identify the main electrostatic interactions which occur between macromolecular chains, between ionic sites on isolated chains or between counterions and polyelectrolytes. Two examples are described. Hyaluronan, a linear alternated copolymer type with one anionic site per repeat unit, is very soluble in water, with a persistence length around 8 nm and a rheological behavior directly related to the molecular weight and polymer concentration in the presence of external monovalent electrolyte. The second example is that of pectin for which the influence of the charge density is studied. It exhibits an important ionic selectivity among divalent counterions in dilute solution with a dimer formation followed by aggregation and gelation.

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“…The same range of limit was obtained by Kohn and Larsen [71,72] who worked on different oligouronates.…”

Section: Polyelectrolyte Characteristicssupporting

confidence: 63%

Polyelectrolyte properties of a plant and animal polysaccharide

Rinaudo¹

2009

Struct Chem

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“…Evidence for the mechanism of gelation can be obtained from the cation binding behavior of isolated block types (19). Both homopolymeric sequences (IIa and b) show the expected statistical cation binding, but polyguluronate sequences also show a sigmoidal increase in binding affinity above a chain length of 18-20 residues.…”

Section: Interrupted Ribbons -Alginates and Pectinsmentioning

confidence: 96%

Conformation and intermolecular interactions of carbohydrate chains

et al. 1977

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For consideration of their conformations and interactions, carbohydrate chains can conveniently be divided into 3 classes on the basis of their covalent structure; namely periodic (a), interrupted periodic (b), and aperiodic (c) types. In aqueous solution carbohydrate chains often exist as highly disordered random coils. Under appropriate conditions, however, polysaccharides of types (a) and (b) can adopt a variety of ordered conformations. Physical methods, and in particular optical rotation, circular dichroism, and nuclear magnetic resonance, provide sensitive probes for the study of the mechanism and specificity of these disorder-order transitions in aqueous solution.Intermolecular interactions between such polysaccharide chains arise from cooperative associations of long structurally regular regions which adopt the ordered conformations. For acidic polysaccharides these cooperative associations may involve alignment of extended ribbons with cations sandwiched between them. In other systems the interactions involve double helices which may then aggregate further, and geometric "matching" of different polysaccharide chains can also occur. These ordered, associated regions are generally terminated by deviations from structural regularity or by "kinks" which prevent complete aggregation of the molecules.The complex carbohydrate chains which occur at the periphery of animal cells have very different, aperiodic structures and although their conformations are as yet poorly understood, preliminary indications are considered.

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“…Measurements on solutions of calcium polymannuronate and polyguluronate of different chain lengths (KOHN and LARSEN 1972) gave considerably lower calcium ion activities in calcium polyguluronate samples with more than 20 units, than of those of lower molecular weight and of all the calcium polymannuronates. This, together with further ion exchange experiments (SMIDSROD and HAUG 1972b), suggested an autocooperative binding in which aggregation of the polyguluronide chains binds more firmly the calcium ions which initiate the aggregation.…”

Section: Ion Exchangementioning

confidence: 99%