Defense against chitin-containing fungal pathogens. Binds the hyphal tips of fungi and degrades nascent chitin. Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Optimum pH is about 5.0. Stable between pH 4-8. Enzyme activity is retained almost fully under 40 degrees Celsius and completely destroyed at 70 degrees Celsius. At 60 degrees Celsius the activity was 15-30% compared to the untreated enzyme. Localized to the starchy endoderm of the seed May localize to other parts of the seed including the aleurone cells (at protein level). Levels increase from 23 to 40 days after flowering, and are maintained until maturation (at protein level). Belongs to the glycosyl hydrolase 19 family. Chitinase class II subfamily.