Purification and characterization of a β-glucosidase from the phytopathogenic fungus Fusarium oxysporum f. sp. melonis

T.M. ALCONADA AND M.J. MARTÍNEZ. 1996. Fusarium oxysporum f. sp. melonis produces cellulase and β‐glucosidase activities in a medium with glucose and avicel as carbon source. A β‐glucosidase from this crude material was purified by gel filtration and ion exchange chromatography successively. This enzyme is a unique band of protein in SDS‐PAGE and isoelectric focussing. It had a molecular weight of 66000 and a pI of 5. Using p‐nitrophenyl‐β‐D‐glucopyranoside as substrate β‐glucosidase shows a Km of 210 μmol 1‐1, an optimum pH of 5.5 and an optimum reaction temperature of 60°C, being stable in a pH range of 5–7 for 48 h at room temperature.