Secreted chitinase involved in the degradation of chitin, a component of the cell walls of fungi and exoskeletal elements of some animals (including worms and arthropods). Participates in the infection process and directly acts in the penetration process of the host cuticle. Involved in heat-shock adaptation. Random endo-hydrolysis of N-acetyl-beta-D-glucosaminide (1->4)-beta-linkages in chitin and chitodextrins. Optimum pH is 4.5-5.0. Optimum temperature is 40-45 degrees Celsius. Induced by chitin and cuticle and repressed by glucose. Protein expression is increased after host tick Boophilus microplus infection. Accumulates also in response to heat-shock stress conditions. Leads to decreased endochitinase and exochitinase activities following heat-shock treatment. Belongs to the glycosyl hydrolase 18 family. Chitinase class III subfamily.