T. Fontaine et al., PURIFICATION AND CHARACTERIZATION OF AN ENDO-1,3-BETA-GLUCANASE FROM ASPERGILLUS-FUMIGATUS, European journal of biochemistry, 243(1-2), 1997, pp. 315-321
An endo-1,3-beta-glucanase was purified from a cell wall autolysate of
Aspergillus fumigatus. This beta-glucanase activity was associated wi
th a glycosylated 74-kDa protein. Using a sensitive colorimetric assay
and a high-performance anion-exchange chromatography with a pulsed el
ectrochemical detector for product analysis, it was shown that the end
oglucanase hydrolysed exclusively linear 1,3-beta-glucan chains, had a
n optimum pH of 7.0 and an optimum temperature of 60 degrees C. A subs
trate kinetic study gave a K-m value of 0.3 mg/ml for soluble (laminar
in and laminari-oligosaccharides) and 1.18 mg/ml for insoluble (curdla
n) 1,3-beta-glucan. Laminari-oligosaccharide degradation, analysed by
HPLC, showed that the endoglucanase bind to the subtrate at several po
sitions and suggested that the active site of the enzyme recognized fi
ve glucose units linked by a 1,3-beta bond. The association of the pre
sent endo-1,3-beta-glucanase with the cell wall of A. fumigatus sugges
ts a putative role for this enzyme during cell-wall morphogenesis.