Purification and characterization of an endo-1,3-beta-glucanase from Aspergillus fumigatus

• Published in: European Journal of Biochemistry 1997-01, Vol.243 (1/2), p.315-321
• Main Authors: Fontaine, T, Hartland, R.P, Beauvais, A, Diaquin, M, Latge, J.P
• Format: Article
• Language: English
• Subjects: Aspergillus fumigatus; Aspergillus fumigatus - enzymology; beta-Glucans; Cell Wall; Cell Wall - enzymology; endo‐1,3‐β‐glucanase; filamentous fungus; Fungal Proteins; Fungal Proteins - isolation & purification; Glucan Endo-1,3-beta-D-Glucosidase; Glucan Endo-1,3-beta-D-Glucosidase - antagonists & inhibitors; Glucan Endo-1,3-beta-D-Glucosidase - isolation & purification; Glucans; Glucans - metabolism; Glycosylation; Hydrogen-Ion Concentration; Life Sciences; Membrane Glycoproteins; Membrane Glycoproteins - isolation & purification; Molecular Weight; plant biochemistry; plant physiology; Polysaccharides; Polysaccharides - metabolism; Substrate Specificity; Temperature
• ISSN: 0014-2956; 1432-1033; 1432-1327
• DOI: 10.1111/j.1432-1033.1997.0315a.x

An endo-1,3-beta-glucanase was purified from a cell wall autolysate of Aspergillus fumigatus. This beta-glucanase activity was associated with a glycosylated 74-kDa protein. Using a sensitive colorimetric assay and a high-performance anion-exchange chromatography with a pulsed electrochemical detector for product analysis, it was shown that the endoglucanase hydrolysed exclusively linear 1,3-beta-glucan chains, had an optimum pH of 7.0 and an optimum temperature of 60 degrees C. A substrate kinetic study gave a Km value of 0.3 mg/ml for soluble (laminarin and laminari-oligosaccharides) and 1.18 mg/ml for insoluble (curdlan) 1,3-beta-glucan. Laminari-oligosaccharide degradation, analysed by HPLC, showed that the endoglucanase bind to the substrate at several positions and suggested that the active site of the enzyme recognized five glucose units linked by a 1,3-beta bond. The association of the present endo-1,3-beta-glucanase with the cell wall of A. fumigatus suggests a putative role for this enzyme during cell-wall morphogenesis.