An enzyme activity similar to that of dextranase is associated with coleoptiles of Avena sativa . When subjected to purified dextranase, both the pure natural dextran and the cell walls of the Avena coleoptiles yield isomaltose and isomaltotriose. Thus, the cell walls contain dextrans or dextran-like compounds. Coleoptiles with low auxin content have a lower dextranase activity than coleoptiles with high auxin content. The enzyme activity is therefore in some way sensitive to the hormone.