title: A study of bioactive, branched (1→3)-β-d-glucans in dimethylacetamide/LiCl and dimethyl sulphoxide/LiCl using size-exclusion chromatography with multi-angle light scattering detection.
abstract: Water-soluble (1→3)-β-d-glucans with 1,6-linked branches (SBG) isolated from the cell walls of Saccharomyces cerevisiae were studied by size exclusion chromatography (SEC) with multi-angle laser light scattering (MALLS) detector using dimethylacetamide (DMAc) containing 0.5% (0.12M) LiCl, or dimethyl sulphoxide (DMSO) in the absence and presence of 0.25M LiCl, respectively, as eluents. The aggregating glucan could be dispersed as single chains in both solvents, with chain length distributions in reasonable agreement with results obtained previously with carboxymethylated glucans in aqueous solvent. However, DMAc is preferred over DMSO because of higher sensitivity in MALLS, and also because the latter produces SEC anomalies. SBG dissolves slowly in DMAc/LICl at room temperature, but heating accelerates the process. The rate of depolymerisation of SBG in DMAc/LiCl at high temperatures (70-105°C) was determined as a basis for defining dissolution procedures at elevated temperatures with a minimum of degradation. The result of the investigation is a simple and reliable protocol for preparing unaggregated, fully dissolved and undegraded SBG in DMAc/LiCl, which is well suited as a standard analysis of the molecular weight distribution of SBG-like molecules without chemical derivatization.
authors.affiliation: NOBIPOL, Department of Biotechnology, Norwegian University of Science and Technology (NTNU), Sem Saelands veg 6/8, NO-7491 Trondheim, Norway.
authors.forename: Fen
authors.initials: F
authors.lastname: Qin
authors.forename: Mürşide
authors.initials: M
authors.lastname: Kes
authors.forename: Bjørn E
authors.initials: BE
authors.lastname: Christensen
mesh_terms: D000081:Acetamides / Q000737:chemistry*; D002850:Chromatography, Gel / Q000379:methods*; D004121:Dimethyl Sulfoxide / Q000737:chemistry*; D005936:Glucans / Q000032:analysis*; D008027:Light; D018021:Lithium Chloride / Q000737:chemistry*; D012542:Scattering, Radiation; D012995:Solubility
chemical_list: D000081:Acetamides; D005936:Glucans; D018021:Lithium Chloride; C013959:dimethylacetamide; D004121:Dimethyl Sulfoxide
keywords: (1→3)-β-d-Glucan; Dimethyl sulphoxide (DMSO); Dimethylacetamide (DMAc); Refractive index increment; SEC-MALLS; Saccharomyces cerevisiae