Potentiometric titration of poly(<scp>L</scp>‐glutamic acid) in aqueous solutions and binding of divalent cations

Kono, Naoko; Ikegami, Akira

doi:10.1002/bip.1966.360040803

Cited by 39 publications

(12 citation statements)

References 10 publications

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“…Since PAA is a weak polyelectrolyte whose titratable ionic groups have a pH-dependent degree of ionization (42,43), ␣, we can control the polymer linear charge density ( ) by fixing pH. "Type I" turbidimetric titrations were carried out by adding 40 mM CTAC to 0.50 g/L NaPAA ϩ 20 mM C 12 bidimetrically, corresponds to the onset of polymer-micelle complexation has been verified by dynamic light scattering, electrophoretic light scattering, and fluorescence spectroscopy (44,45).…”

Section: Resultsmentioning

confidence: 99%

Binding of Polycarboxylic Acids to Cationic Mixed Micelles: Effects of Polymer Counterion Binding and Polyion Charge Distribution

Yoshida

Sokhakian

Dubin

1998

Journal of Colloid and Interface Science

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Mixed micelles of cetyltrimethylammonium chloride (CTAC) and n-dodecyl hexaoxyethylene glycol monoether (C 12 E 8 ) bind to polyanions when the mole fraction of the cationic surfactant exceeds a critical value (Y c ). Y c corresponds to a critical micelle surface charge density at which polyelectrolyte will bind to this colloidal particle. Turbidimetric titrations were used to determine Y c for such cationic-nonionic micelles in the presence of acrylic acid and acrylamido-2-methylpropane sulfonate homopolymers (PAA and PAMPS, respectively) and their copolymers with acrylamide, as function of pH, ionic strength, and polyelectrolyte counterion. In 0.20 M NaCl, Y c for PAA is found to be remarkably insensitive to pH, i.e., virtually independent of the apparent polymer charge density app . On the other hand, the expected inverse relationship between Y c and app is observed either for PAA when NaCl is replaced by TMACl (tetramethylammonium chloride), or when app is manipulated using acrylic acid/acrylamide copolymers at high pH. The effective charge density of PAA is thus seen to be suppressed by specific sodium ion binding, indicating that the influence of salts on the interaction of polycarboxylic acids with colloidal particles may differ qualitatively from their effect on the analogous behavior of strong polyanions. Comparisons between homo-and copolymers of acrylic acid were carried out also to test the hypothesis that the "mobility" of charges on PAA at moderate pH (degree of ionization less than unity) could make this "annealed" polymer exhibit the behavior of a more highly charged one. The results, while consistent with this expectation, were obscured by the likely effect of copolymer sequence distributions.

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Section: Resultsmentioning

confidence: 99%

Binding of Polycarboxylic Acids to Cationic Mixed Micelles: Effects of Polymer Counterion Binding and Polyion Charge Distribution

Yoshida

Sokhakian

Dubin

1998

Journal of Colloid and Interface Science

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“…This action also causes radial chain expansion, allowing formation of a void near the center of the helix. This void is capable of sequestering cations because of the surrounding negative electrostatic field …”

Section: Background and Theorymentioning

confidence: 99%

Surface Modification of Silica- and Cellulose-Based Microfiltration Membranes with Functional Polyamino Acids for Heavy Metal Sorption

et al. 1999

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Functionalized membranes represent a field with multiple applications. Examination of specific metal−macromolecule interactions on these surfaces presents an excellent method for characterization of these materials. These interactions may also be exploited for heavy metal sorption from drinking and industrial water sources. Various low-capacity, silica-based ion-exchange and chelating sorbents (about 0.5 mmol of metal/g of resin) are available for treatment of such waters. Cellulosic membrane-based sorbents, functionalized with polyamino acids, present an excellent approach for high-capacity (3−14 mmol of metal/g of sorbent) metal sorption. Silica-based membrane sorbents possess metal sorption capacities approaching those of cellulosic-based membranes, with the added benefits of excellent acid and solvent resistance. Metal sorption capacities of silica-based membrane sorbents with various polyamino acids range from 0.6 mmol to 1.4 mmol of metal/g of sorbent. Ion exchange, chelation, and electrostatic interactions form the basis of metal sorption. Electrostatic interactions are greatly magnified in membrane-based sorbents, and are partly responsible for their high capacities. Regeneration of these sorbents has also been shown, including the possibility for selective desorption of metals.

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“…Method A (Kono & Ikegami, 1966). The titration of the anions in the absence of metal ions may be represented by:…”

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confidence: 99%

The binding of calcium and yttrium ions to a glycoprotein from bovine cortical bone

Williams

Peacocke

1967

Biochemical Journal

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The binding of Ca2+ and Y3+ to an acidic glycoprotein from bovine cortical bone, bone sialoprotein, was determined from the titration curves at I 0 2 in the presence and absence of the cations. The binding of Y3+ was greater than that of Ca2+. The value for the association constant, k, for the interaction with Y3+ increased with pH, from logik 2-93 at pH 3-4 to logk 3 50 at pH4-4, and the number of binding sites/mol. increased from 4 6 at pH3 4 to 9-1 at pH4 4. It is proposed that the binding site consists of three carboxyl groups, but it is likely that the binding is a strong electrostatic interaction rather than a co-ordination linkage. A chondroitin sulphateprotein complex also extracted from bovine cortical bone interacted with Y3+ and Ca2+ to a similar extent as did bone sialoprotein. It is suggested that these materials are present in bone at the resting and resorbing surfaces and that they contribute to the deposition of yttrium, americium and plutonium at these sites.

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Potentiometric titration of poly(L‐glutamic acid) in aqueous solutions and binding of divalent cations

Cited by 39 publications

References 10 publications

Binding of Polycarboxylic Acids to Cationic Mixed Micelles: Effects of Polymer Counterion Binding and Polyion Charge Distribution

Binding of Polycarboxylic Acids to Cationic Mixed Micelles: Effects of Polymer Counterion Binding and Polyion Charge Distribution

Surface Modification of Silica- and Cellulose-Based Microfiltration Membranes with Functional Polyamino Acids for Heavy Metal Sorption

The binding of calcium and yttrium ions to a glycoprotein from bovine cortical bone

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