Levans produced by several Zymomonas mobilis strains were classified by the
ir viscosity average molecular weight and tested against sarcoma 180. Measu
rements of the samples' polydispersity were carried out to characterise the
molecular weight distribution. The antitumour activities of levan samples
were plotted against the viscosity average molecular weight and a maximum v
alue of this activity was found at (M) over bar(v) = 210 000 ((M) over bar(
w) = 456 900 and PD = 16.2). The results indicate that levan antitumour act
ivities depend on the polysaccharide molecular weight and that a specific c
lass of molecular weight may be responsible for this effect. (C) 2000 Elsev
ier Science B.V. All rights reserved.