Alfalta-stem pectins: enzymic degradation and structural characterization of a buffer-soluble fraction
✍ Scribed by Ronald D. Hatfield
- Publisher
- Elsevier Science
- Year
- 1991
- Tongue
- English
- Weight
- 745 KB
- Volume
- 212
- Category
- Article
- ISSN
- 0008-6215
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✦ Synopsis
Carbohydrate material solubilized from alfalfa (Medicago sativa L.) stem cell walls with hot 1OmM potassium phosphate (pH 7.0) was fractionated into neutral and acidic components by anion-exchange chromatography.
Glycosyl-composition and glycosyl-linkage analysis indicated that the neutral fraction contained arabinogalactan type I and that the major acidic fraction was composed of rhamnogalacturonans. The rhamnogalacturonans were resistant to depolymerization by endo-( 1+4)-cr-D-galacturonanase. Saponification of the rhamnogalacturonans followed by acidification to pH 5 gave a precipitate and a soluble fraction. The precipitate after resolubilization was extensively depolymerized by endo-( 1+4j-a-D-galacturonanase. Rhamnogalacturonans in the soluble fraction, which contained a high proportion of neutral sugar residues, were only partially depolymerized by endo-( l-4)-a-D-galacturonanase.
Products separated by gel filtration were shown by glycosyl-composition analysis to be composed of different proportions of neutral sugar residues and galactosyluronic residues.