Endochitinase from Aspergillus nidulans implicated in the autolysis of its cell wall

Abstract

An endochitinase from centrifuged autolyzed cultures of Aspergillus nidulans has been purified 100 times. The enzyme has Mw 27 000, pI of 4.8 units, pH optimum around 5 pH units. It is unstable at temperature > 70°C and does not have a cation requirement. It is inhibited by Hg2+, Cu2+, Ca2+ and Ag+ and it does not have muramidase activity. The enzyme depolymerizes chitin rapidly with production of high molecular weight polysaccharides, and then slowly degrades these with production of N,N′-diacetylchitobiose. The enzyme hydrolyzes N,N′,N″-triacetylchitotriose with production of N,N′-diacetylchitobiose and N-acetylglucosamine and this hydrolysis is inhibited by other chitin oligomers and N-acetylglucosamine. This enzyme hydrolyzes in the same way the chitin obtained from the cell wall of Aspergillus nidulans. © 1989.