S. Kitamura et al., CONFORMATION OF (2-]1)-BETA-D-FRUCTAN IN AQUEOUS-SOLUTION, International journal of biological macromolecules, 16(6), 1994, pp. 313-317
The conformation and dilute solution properties of (2 --> 1)-beta-D-fr
uctan in agueous solution were studied by gel permeation chromatograph
y, low-angle laser light-scattering photometry, viscometry, small-angl
e X-ray scattering and electron microscopy. Fractions covering a broad
range of weight-average molecular weights (M(w)) from 1.49 x 10(4) to
5.29 x 10(6) were obtained from a native sample by ultrasonic degrada
tion and fractional precipitation. For M(w) < 4 x 10(4), the intrinsic
viscosity [eta] varies with M(w)(0.71), indicating that the fructan c
hain behaves as a random coil expanded by an excluded-volume effect in
this molecular weight region. For M(w) > 10(5), [eta] exhibits an unu
sually weak dependence on M(w) and finally becomes almost independent
of molecular weight. This behaviour is interpreted in terms of a globu
lar conformation of the high-molecular-weight fructan molecules. Small
-angle X-ray-scattering measurements and electron microscopic observat
ions support this interpretation of the values of [eta] observed.