Pectic Substances from Soybean Cell Walls Distinguish Themselves from other Plant Cell Walls Pectins

Abstract

A review. In soybean cell wall material, pectic substances are the major non-starch polysaccharide. These pectic substances distinguish themselves from pectic substances of cell wall material from other plants in the absence of homogalacturonan, the presence of fucose residues in the xylogalacturonan, and two uncommon structural features of the pectic arabinogalactan side chains, namely the presence of internal (1,5)-linked arabinofuranose and terminal arabinopyranose. Therefore, these pectic substances are rather resistant to degrdn. by both established (like polygalacturonase) and novel (like RG-hydrolase) pectic enzymes. The hemicellulosic polysaccharides in the soybean cell wall appeared to be predominantly xyloglucans, composed of XXXG-type building units like most legume xyloglucans. The uncommon structural features of soybean cell wall pectic substances explain their resistance to degrdn. by enzymes generally used to degrade this kind of polymers, and indicates that a search for new enzymes is required to enable enzymic modification of these polysaccharides. [on SciFinder(R)]