Premium
Potentiometric studies of hydrophobic effect on ion binding of ionic dextran derivatives
Author(s) -
Gekko Kunihiko,
Noguchi Hajime
Publication year - 1975
Publication title -
biopolymers
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.556
H-Index - 125
eISSN - 1097-0282
pISSN - 0006-3525
DOI - 10.1002/bip.1975.360141211
Subject(s) - chemistry , potentiometric titration , dextran , counterion , ionic bonding , polymer chemistry , ion , organic chemistry
In order to clarify the effect of degree of substitution of ionic and hydrophobic group on the polyelectrolytic behavior of polysaccharides, potentiometric titration and activity measurement of counterions were made for carboxymethyldextran (Cm‐dextran) having various degrees of substituted carboxyl group and for carboxymethylbenzyldextran (Cm‐Bzl‐dextran) containing various degrees of substituted benzyl group. From the shape of titration curve, no conformational change was observed for both Cm‐dextran and Cm‐Bzl‐dextran. The p K 0 value of Cm‐dextran was independent of the degree of the degree of substituted carboxy group. However, the p K 0 of Cm‐Bzl‐dextran increased with an increasing degree of substituted benzyl group. The suppression of dissociation of a carboxyl group, caused by the surrounding hydrophobic groups, was discussed mainly in terms of the change of water structure around such groups. From the results of activity measurement for counterions of these dextran derivatives, we proposed the possibility of ion selectivity based on the hydrophobicity.