The Structure of Arabinoxylan and Arabinoglucuronoxylan Isolated from Rice Endosperm Cell Wall

Abstract

A neutral and an acidic arabinoxylan fraction (H-1 and H-2) were obtained from rice endosperm cell wall. The results of methylation analysis and partial hydrolysis of these fractions showed that both of them have highly branched structures in which approximately 6 out of 7 (H-1) and 5 out of 6 (H-2) of the (l->4)-linked d-xylose residues are branched. Most of the side chains in H-1 consists of single α-l-arabinofuranose residues, whereas some of them in H-2 were substituted with α-d-glucuronic acid or 4-O-methyl-α-D-glucuronic acid residues, both attached to the O-2 position of D-xylose residues. These highly branched arabinoxylans are not readily hydrolyzed by an endoxylanase of Streptomyces sp. © 1983, Japan Society for Bioscience, Biotechnology, and Agrochemistry. All rights reserved.