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Solvent‐dependent conformation of a regioselective amylose carbamate: Amylose‐2‐acetyl‐3,6‐bis(phenylcarbamate)
Author(s) -
Tsuda Maiko,
Terao Ken,
Kitamura Shinichi,
Sato Takahiro
Publication year - 2012
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.22118
Subject(s) - chemistry , amylose , persistence length , molar mass , radius of gyration , crystallography , solvent , intramolecular force , intrinsic viscosity , intermolecular force , analytical chemistry (journal) , stereochemistry , polymer , organic chemistry , molecule , starch
Abstract Six amylose‐2‐acetyl‐3,6‐bis(phenylcarbamate) (AAPC) samples ranging in weight‐average molar mass M w from 1.8 × 10 4 g mol −1 to 1.1 × 10 6 g mol −1 have been prepared from enzymatically synthesized amylose samples. Static light scattering, small‐angle X‐ray scattering, sedimentation equilibrium, and viscosity measurements were made for the samples in 1,4‐dioxane (DIOX), 2‐ethoxyethanol (2EE), and 2‐butanone (MEK) all at 25°C to determine particle scattering functions, z ‐average radii of gyration, intrinsic viscosities, as well as M w . The data were analyzed in terms of the wormlike cylinder model mainly to yield the helix pitch per residue h and the Kuhn segment length λ −1 , which corresponds to twice of the persistence length. The latter parameters (λ −1 ) in 2EE (11 nm) and MEK (12 nm) are quite smaller than those for amylose tris(phenylcarbamate) (ATPC) in the same solvent (16 nm in 2EE and 18 nm in MEK) whereas those for AAPC (21 nm) and ATPC (22 nm) in DIOX are essentially the same as each other. This indicates that the chain stiffness of AAPC is more strongly influenced by the solvents since the number of intramolecular H‐bonds of AAPC is more changeable than that for ATPC. © 2012 Wiley Periodicals, Inc. Biopolymers 97:1010–1017, 2012.