Purification and Partial Characterization of a Glucan Containing Indole-3-acetic Acid.

The "bound auxin" of Zea mays, first described by Berger and Avery (Amer. J. Bot. 1944; 31: 199-203) has been purified and partially characterized. It is an indole-3-acetic acid-containing, high molecular weight, lipophilic cellulosicglucan. The indole-3-acetic acid is in ester linkage as evidenced by indoleacetamide formation upon ammonolysis. The glucan is of variable chain length and comprises, in general, 35 to 50 per cent of the dry weight of the compound. The glucosidic residues are beta 1 --> 4 linked and are hydrolyzed by cellulase. Mild acid hydrolysis produces cellobiose and cellotriose. Other components, as yet unidentified, of the compound are described.