title: Structural and physiological studies on the storage beta-polyglucan of haptophyte Pleurochrysis haptonemofera.
abstract: The storage beta-polyglucan and catabolic enzyme activities of the haptophyte Pleurochrysis haptonemofera were characterized. The storage beta-polyglucan was prepared by the dimethylsulfoxide-extraction method. (13)C- and (1)H-NMR spectroscopy revealed that the polyglucan consists of beta-(1-->3)- and beta-(1-->6)-linked glucose polymers, with a beta-(1-->6)- to beta-(1-->3)-linkage ratio of 1.5. Gel permeation chromatography showed that the molecular weight of the polyglucan is 1.1-8.4 x 10(4) Da, with a peak at 3.4 x 10(4) Da. The degree of polymerization, which was estimated from the amounts of total carbohydrate and reduced ends, was 203, corresponding to 3.3 x 10(4) Da. A method for measurement of the beta-polyglucan in a small amount of liquid culture involving a mixture of beta-glucanases, Westase, was established. The beta-polyglucan was localized in the soluble fraction of cells. The amount of beta-polyglucan per cell increased at the stationary phase under continuous illumination and decreased in the dark, like those of storage alpha-polyglucans, starch of green algae and glycogen of cyanobacteria. The activities of beta-1,3- and beta-1,6-glucanases involved in the degradation of the storage beta-polyglucan were assayed in vitro, both being optimal at pH 5.0. The beta-1,3-glucanase activity, which was detected on active staining after native polyacrylamide gel electrophoresis, was partially purified by ammonium sulfate precipitation and anion exchange chromatography.
authors.affiliation: School of Life Sciences, Tokyo University of Pharmacy and Life Sciences, 1432-1, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Hirokawa
authors.forename: Shoko
authors.initials: S
authors.lastname: Fujiwara
authors.forename: Motoya
authors.initials: M
authors.lastname: Suzuki
authors.forename: Tomoka
authors.initials: T
authors.lastname: Akiyama
authors.forename: Minako
authors.initials: M
authors.lastname: Sakamoto
authors.forename: Saori
authors.initials: S
authors.lastname: Kobayashi
authors.forename: Mikio
authors.initials: M
authors.lastname: Tsuzuki
mesh_terms: D056890:Eukaryota / Q000737:chemistry / Q000254:growth & development / Q000378:metabolism*; D043326:Glucan 1,3-beta-Glucosidase / Q000378:metabolism; D005936:Glucans / Q000737:chemistry / Q000302:isolation & purification / Q000378:metabolism*; D008027:Light; D015394:Molecular Structure
chemical_list: D005936:Glucans; D043326:Glucan 1,3-beta-Glucosidase