Premium
Ionic polysaccharides. IV. Free‐rotation dimensions for disaccharide polymers. Comparison with experiment for hyaluronic acid
Author(s) -
Cleland Robert L.
Publication year - 1970
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.1970.360090707
Subject(s) - chemistry , disaccharide , polymer , degree of polymerization , intrinsic viscosity , crystallography , polymerization , stereochemistry , organic chemistry
The root‐mean‐square end‐to‐end distance has been calculated for a model allowing free rotation about glycoside bonds for the general case of polysaccharides having a disaccharide repeating unit. Numerical estimates are given for several naturally occurring structures based on an idealized pyranose unit in the C 1 chair conformation. Extrapolation procedures which make use of the intrinsic viscosity [η] in good solvents to obtain unperturbed dimensions do not represent, data for hyaluronic acid very well, especially at low molecular weights. However, order‐of‐magnitude estimates suggest that this polymer behaves similarly to other polysaccharides, and probably has stiffer local structure than typical non‐ionic synthetic polymers. A double logarithmic plot of the product of [η] and M̄ w , the weight‐average molecular weight, against the degree of polymerization in the range for M̄ w of 10 4 to 2 × 10 4 permits a straight‐line fit of available data for all the glycosaminoglycans, including heparin and the chondroitin sulfates, as well as sodium carboxymethyl cellulose. This result suggests similarity of short‐chain hydrodynamic behavior of these polymers.