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Optical rotation of some α‐1,4‐linked glucopyranosides in the system H 2 O–DMSO and solution conformation of amylose
Author(s) -
Dintzis F. R.,
Tobin R.
Publication year - 1969
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.1969.360070414
Subject(s) - chemistry , amylose , specific rotation , optical rotation , polymer , intrinsic viscosity , dimethyl sulfoxide , solvent , crystallography , starch , random coil , refractive index , polymer chemistry , stereochemistry , organic chemistry , circular dichroism , optics , physics
The specific rotation of starch components, corrected for refractive index variation, exhibits a discontinuity in the region of the water–dimethyl sulfoxide (H 2 O–DMSO) system that corresponds to the composition of the complex 2H 2 O–DMSO. This discontinuity is a property dependent upon the presence of a number of consecutively linked α‐1,4 glucose units and, therefore, must reflect a change in symmetry of a segment, of polymer chain. The optical rotation of amylose between 26.5 and 92.5°C. does not change in DMSO and is only slightly lowered in water at the higher temperature. The behavior of amylose in both DMSO and H 2 O is like that of a random coil, as indicated by viscosity and sedimentation measurements. These results may be interpreted either as being compatible with models of amylose in solution in which the polymer backbone has helical twist, or as indicating removal of strong interactions between polymer chain segments by a good solvent.