title: Correlation between the antitumor activity of a polysaccharide schizophyllan and its triple-helical conformation in dilute aqueous solution.
abstract: Eight samples of a polysaccharide schizophyllan ranging in weight-average molecular weight Mw (in water) from 5 x 10(3) to 1.3 x 10(5) were prepared and their antitumor activity (expressed in terms of the tumor inhibition ratio) against Sarcoma 180 ascites, intrinsic viscosities [eta], and gel-filtration chromatograms in aqueous solution were determined. The tumor inhibition ratio was essentially unity for samples with Mw higher than 9 x 10(4), but reduced to zero or even to a negative value when Mw was lower than 10(4). The [eta] data combined with the chromatographic data showed that above Mw approximately 9 x 10(4) the predominant species of schizophyllan in aqueous solution is the previously found rigid triple helix, whereas below Mw approximately 9 x 10(4) both triple helices and single chains coexist in the solution and the fraction of triple helices decreases monotonically to zero as Mw is decreased to 5 x 10(3). From these findings it was concluded that the antitumor potency of schizophyllan in water is related to the amount of triple helices relative to that of single chains.
authors.affiliation: Research Laboratory, Taito Co, Higashishiruke-shinmachi, Nagata-ku, Kobe 653 Japan.
authors.forename: T
authors.initials: T
authors.lastname: Yanaki
authors.forename: W
authors.initials: W
authors.lastname: Ito
authors.forename: K
authors.initials: K
authors.lastname: Tabata
authors.forename: T
authors.initials: T
authors.lastname: Kojima
authors.forename: T
authors.initials: T
authors.lastname: Norisuye
authors.forename: N
authors.initials: N
authors.lastname: Takano
authors.forename: H
authors.initials: H
authors.lastname: Fujita