Complex chitinolytic system of Aspergillus fumigatus

Native polyacrylamide gels incorporating a glycol chitin substrate were used to detect several chitinolytic enzymes in the culture filtrate and cell surface, wall and mixed membrane fractions of Aspergillus fumigatus during the exponential phase of growth. Much of the cellular chitinase activity did not bind to concanavalin A (Con A) matrix and was heat-sensitive. In contrast, almost all chitinases secreted appeared to be heat-stable glycoproteins. The heavily glycosylated molecules, in a Con A-binding fraction, were the most immunologically-reactive components, as judged by their binding to anti-Aspergillus antibodies, present in the serum of patients with aspergillosis. Most of the cellular chitinases of A. fumigatus mycelium bound to an insoluble chitin matrix while most of the secreted chitinases did not bind to chitin.