ENZYMATIC DISSOCIATION OF ZEA SHOOT CELL-WALL POLYSACCHARIDES .6. STRUCTURAL CHARACTERIZATION OF AN ARABINOXYLAN RHAMNO-GALACTURONAN COMPLEX FROM CELL-WALLS OF ZEA SHOOTS

An arabinoxylan-rhamnogalacturonan complex, comprised of galacturonic acid, rhamnose, arabinose, xylose, and galactose in the ratios 75.9:4.6:5.2:3.5:5.4 and lesser amounts of other constituents, was dissociated from the water-insoluble matrix of cell walls of Zea mays by xylanase and glucuronoxylanase treatment. The solubilized complex retained its integrity when subjected to a series of separation procedures, and analysis of the sugar components throughout the elution profiles exhibited consistent ratios. The complex was subjected to controlled degradation by pectate lyase and pectin lyase, yielding two components comprised of rhamnose, fucose, arabinose, xylose, galactose, and galacturonic acid in the ratios 10.9:1.5:13.1:16.9:27.7:30.0 and 8.5:1.7:11.8:6.6:17.3:54.0, respectively, in addition to di-, tri-, and tetra-saccharides of galacturonic acid. The non-reducing terminals of the latter were characterized by the presence of 4,5-unsaturated hexuronic acid. The structural features of the two complex fractions were partially characterized.