An Acidic Arabinogalactan-Protein from the Roots ofBaptisia tinctoria
| Autor: | Birgit Classen, Wolfgang Blaschek, Maren Wack |
|---|---|
| Rok vydání: | 2005 |
| Předmět: |
Pharmaceutical Science
Plant Roots Analytical Chemistry chemistry.chemical_compound Mucoproteins Arabinogalactan Drug Discovery Humans Plant Proteins Arabinogalactan protein Pharmacology Chromatography biology Plant Extracts Organic Chemistry Fabaceae Hydrogen-Ion Concentration Galactan Carbohydrate Glucuronic acid biology.organism_classification Complementary and alternative medicine chemistry Reagent Molecular Medicine Acid hydrolysis Phytotherapy Baptisia |
| Zdroj: | Planta Medica. 71:814-818 |
| ISSN: | 1439-0221 0032-0943 |
| DOI: | 10.1055/s-2005-871247 |
| Popis: | An acidic arabinogalactan-protein (AGP) isolated from an aqueous extract of the roots of wild indigo [ Baptisia tinctoria (L.) R. Br.] by precipitation with beta-glucosyl Yariv reagent consists of L-arabinose (34.0 %) and D-galactose (58.7 %) (1 : 1.7), minor amounts of D-glucuronic acid (4.0 %) and traces of D-rhamnose (2.3 %) and D-glucose (1 %). The protein part of the AGP mainly contains asparagine/aspartic acid (11.3 %), glutamine/glutamic acid (10.8 %), alanine (8.0 %), serine (8.0 %), leucine (7.0 %) and hydroxyproline (6.3 %). Methylation analysis revealed that the carbohydrate moiety of the glycoprotein has a highly branched structure. The core consists of 3-linked beta- D-galactopyranose units carrying side chains of 6-linked beta- D-galactopyranose in position C(O)6, partly substituted in position C(O)3 by side chains of 5- and 3-linked alpha- L-arabinofuranosyl residues and 4-linked beta- D-galactopyranose units. Galactose and arabinose as well as glucose, rhamnose and glucuronic acid occur in terminal positions. The presence of these glycosyl linkage types was confirmed by (13)C-NMR data. The AGP was separated into two fractions by SEC. The major peak corresponded to a hydrodynamic volume of 5.6 x 10 (4) Da (AGP-F2) and the minor peak to a hydrodynamic volume of 1.2 x 10 (6) Da (AGP-F1). MALLS revealed apparent weight average molecular masses of 1.4 x 10 (5) Da and1.0 x 10 (7) Da, respectively. Both fractions show corresponding carbohydrate compositions and structural features with regard to the carbohydrate moiety. Mild acid hydrolysis of the AGP leads to loss of terminal arabinofuranosyl units. The residual galactan backbone does not react with the Yariv reagent in gel diffusion tests while the total AGP still interferes with the reagent following reduction of terminal glucuronic acid residues. |
| Databáze: | OpenAIRE |
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