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 d imensions. The chain of beta-glucan is satisfactorily modelled by a pa rtially stiff worm-like cylinder, with persistence length 3.5-3.8 nm a nd cross-section diameter 0.45 nm. This corresponds to an average of a bout four beta(1-->3) links per statistical segments. The characterist ic ratio, C-infinity, calculated from this worm-like description of th e macromolecule, gave a value of 13-14, in good agreement with the the oretical calculations. (C) 1997 Elsevier Science Ltd.