Functions both as a chitinase and as a N-acetyl-D-glucosamine binding lectin. Inhibits the growth of several phytopathogenic chitin-containing fungi. Possesses also insecticidal activity and superantigenic properties. Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Monomer and homodimer. Zinc favors dimerization. Active in the monomeric form but probably inactive in the dimeric form. The interaction with glycans on the mammalian TCR and MHC molecules of the T-cell and antigen-presenting cell, respectively, is inhibited by oligomers of GlcNAc. Rhizomes and inflorescence with immature seeds. Proteolytically processed to yield a very small protein (8.5 kDa, 86 AA) containing only the two chitin-binding domains.