Physical and structural properties of barley (1->3),(1->4)-beta-D-glucan .2. Viscosity, chain stiffness and macromolecular dimensions

Intrinsic viscosities and molecular weights of (1-->3),(1-->4)-beta-D-glucan samples, covering a range of 9 x 10(3)-6 x 10(5) daltons, have been used to determine their conformational parameters and molecular dimensions. The chain of beta-glucan is satisfactorily modelled by a partially stiff worm-like cylinder, with persistence length 3.5-3.8 nm and cross-section diameter 0.45 nm. This corresponds to an average of about four beta(1-->3) links per statistical segments. The characteristic ratio, C-infinity, calculated from this worm-like description of the macromolecule, gave a value of 13-14, in good agreement with the theoretical calculations. (C) 1997 Elsevier Science Ltd.