title: Characterization of an arabinogalactan-protein isolated from pressed juice of Echinacea purpurea by precipitation with the beta-glucosyl Yariv reagent.
abstract: An arabinogalactan-protein (AGP) from pressed juice of Echinacea purpurea herb was isolated from a high molecular weight fraction by precipitation with the beta-glucosyl Yariv reagent, followed by gel-permeation chromatography. It revealed characteristic features of other AGPs: i.e., a high amount of polysaccharide (83%) with a ratio of galactose to arabinose of 1.8:1, some uronic acids (4-5%), and a low protein content (7%) with high levels of serine, alanine and hydroxyproline. The molecular weight was estimated to be 1.2 x 10(6) Da. Linkage and 13C NMR analyses showed that the AGP is composed of a highly branched core polysaccharide of 3-, 6-, and 3,6-linked Galp residues with terminal Araf, GlcAp and terminal units of Araf-(1-->5)-Araf-(1-->. Partial acid hydrolysis resulted in loss of Araf residues at the periphery of the molecule. Complete loss of reactivity toward the beta-glucosyl Yariv antigen was then noticed.
authors.affiliation: Department of Pharmaceutical Biology, Institute of Pharmacy, University of Kiel, Germany.
authors.forename: B
authors.initials: B
authors.lastname: Classen
authors.forename: K
authors.initials: K
authors.lastname: Witthohn
authors.forename: W
authors.initials: W
authors.lastname: Blaschek
mesh_terms: D002236:Carbohydrate Conformation; D011232:Chemical Precipitation; D002850:Chromatography, Gel; D020900:Echinacea / Q000737:chemistry*; D005685:Galactans / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D005960:Glucosides; D006023:Glycoproteins / Q000032:analysis / Q000737:chemistry* / Q000302:isolation & purification; D007202:Indicators and Reagents; D009682:Magnetic Resonance Spectroscopy; D008970:Molecular Weight; D010696:Phloroglucinol / Q000031:analogs & derivatives*; D010936:Plant Extracts / Q000737:chemistry; D010946:Plants, Medicinal
chemical_list: D005685:Galactans; D005960:Glucosides; D006023:Glycoproteins; D007202:Indicators and Reagents; D010936:Plant Extracts; C104977:Yariv reagent; D010696:Phloroglucinol; C005653:arabinogalactan