COMPLEX CHITINOLYTIC SYSTEM OF ASPERGILLUS-FUMIGATUS

Native polyacrylamide gels incorporating a glycol chitin substrate wer e used to detect several chitinolytic enzymes in the culture filtrate and cell surface, wall and mixed membrane fractions of Aspergillus fum igatus during the exponential phase of growth. Much of the cellular ch itinase 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, i n a Con A-binding fraction, were the most immunologically-reactive com ponents, as judged by their binding to anti-Aspergillus antibodies, pr esent in the serum of patients with aspergillosis. Most of the cellula r chitinases of A. fumigatus mycelium bound to an insoluble chitin mat rix while most of the secreted chitinases did not bind to chitin.