Open AccessInducible chitinolytic system of Aspergillus fumigatus
Author(s) -
Gemma M. Escott,
Veronica M. Hearn,
David J. Adams
Publication year - 1998
Publication title -
microbiology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.019
H-Index - 179
eISSN - 1465-2080
pISSN - 1350-0872
DOI - 10.1099/00221287-144-6-1575
Subject(s) - chitin , chitinase , extracellular , aspergillus fumigatus , biochemistry , enzyme , microbiology and biotechnology , ammonium sulfate precipitation , biology , enzyme assay , chemistry , size exclusion chromatography , chitosan
Incubation of Aspergillus fumigatus NCPF 2140 in growth medium containing 1 % chitin as sole carbon source led to induction of specific extracellular chitinolytic activity of 1.5 μmol GlcNAc released min -1 (mg protein)-1. The effect was repressed by the inclusion of GlcNAc in the medium, indicating regulation by a negative feedback mechanism. Extracellular chitinase activity was inhibited by allosamidin (IC 50 0.12 μM). Multiple chitinolytic enzymes were detected on zymograms of extracellular preparations; levels of individual enzymes induced were dependent upon whether cells were incubated with purified colloidal chitin or a crude preparation of crystalline chitin. A major, inducible, 45 kDa chitinase was purified using ammonium sulphate precipitation, chitin affinity chromatography and a novel procedure involving the electroelution of the enzyme from a substrate gel containing glycol chitin. The enzyme is a glycoprotein with endochitinase activity.