title: Partial characterization and anticoagulant activity of a heterofucan from the brown seaweed Padina gymnospora.
abstract: The brown algae Padina gymnospora contain different fucans. Powdered algae were submitted to proteolysis with the proteolytic enzyme maxataze. The first extract of the algae was constituted of polysaccharides contaminated with lipids, phenols, etc. Fractionation of the fucans with increasing concentrations of acetone produced fractions with different proportions of fucose, xylose, uronic acid, galactose, and sulfate. One of the fractions, precipitated with 50% acetone (v/v), contained an 18-kDa heterofucan (PF1), which was further purified by gel-permeation chromatography on Sephadex G-75 using 0.2 M acetic acid as eluent and characterized by agarose gel electrophoresis in 0.05 M 1,3 diaminopropane/acetate buffer at pH 9.0, methylation and nuclear magnetic resonance spectroscopy. Structural analysis indicates that this fucan has a central core consisting mainly of 3-beta-D-glucuronic acid 1-> or 4-beta-D-glucuronic acid 1 ->, substituted at C-2 with alpha-L-fucose or beta-D-xylose. Sulfate groups were only detected at C-3 of 4-alpha-L-fucose 1-> units. The anticoagulant activity of the PF1 (only 2.5-fold lesser than low molecular weight heparin) estimated by activated partial thromboplastin time was completely abolished upon desulfation by solvolysis in dimethyl sulfoxide, indicating that 3-O-sulfation at C-3 of 4-alpha-L-fucose 1-> units is responsible for the anticoagulant activity of the polymer.
authors.affiliation: Laboratório de Glicobiologia, Departamento de Bioquímica, Universidade Federal do Rio Grande do Norte, Natal, Brasil.
authors.forename: T M A
authors.initials: TM
authors.lastname: Silva
authors.forename: L G
authors.initials: LG
authors.lastname: Alves
authors.forename: K C S
authors.initials: KC
authors.lastname: de Queiroz
authors.forename: M G L
authors.initials: MG
authors.lastname: Santos
authors.forename: C T
authors.initials: CT
authors.lastname: Marques
authors.forename: S F
authors.initials: SF
authors.lastname: Chavante
authors.forename: H A O
authors.initials: HA
authors.lastname: Rocha
authors.forename: E L
authors.initials: EL
authors.lastname: Leite
mesh_terms: D000925:Anticoagulants / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D001777:Blood Coagulation / Q000187:drug effects; D004587:Electrophoresis, Agar Gel; D006801:Humans; D009682:Magnetic Resonance Spectroscopy; D010314:Partial Thromboplastin Time; D000459:Phaeophyceae / Q000737:chemistry*; D011134:Polysaccharides / Q000737:chemistry* / Q000302:isolation & purification / Q000494:pharmacology; D012624:Seaweed / Q000737:chemistry*; D013918:Thrombin Time
chemical_list: D000925:Anticoagulants; D011134:Polysaccharides; C007789:fucoidan