Cell wall autolytic activities and distribution of cell wall glucanases inZea mays L. seedlings

Exo- and endo-glucanases mediate specific degradation of cell wall (1,3)(1, 4)-beta-D-glucans and these enzymes have been related to auxin-mediated gro wth and development of cereal coleoptiles. However? their distribution and functions have not been well established in other tissues. In this study th e glucanase activities and cell wall autolytic activities of different maiz e organs were determined. Autolysis assays serve to evaluate the hydrolysis of cell wall polymers in situ by measuring the sugars released from the in soluble cell wall matrix resulting from the action of bound enzymes. Autoly tic activities were observed in the cell walls of elongating young leaves, mesocotyl and roots of maize. Wall proteins extracted from all of these str uctures are enriched in several types of glucanases and other wall polysacc haride hydrolases. These enzymes therefore appear to have a widespread and fundamental role in wall metabolism in growing tissues (C) 2000 Elsevier Sc ience B.V. All rights reserved.