Purification and Characterization of a Novel α-L-Fucosidase from Fusarium oxysporum Grown on Sludge

Abstract

A novel α-L-fucosidase was found in the culture broth of Fusarium oxysporum isolated from a soil sample when the fungus was cultivated on a liquid active sludge hydrolyzate medium. The enzyme was not found in the culture broth of the fungus grown on glucose medium. The α-L-fucosidase from the fungus was purified to homogeneity by polyacrylamide gel electrophoresis after ammonium sulfate fractionation and successive column chromatographies on DEAE-Sephadex A-50, hydroxylapatite, Sephadex G-150 and Con A-Sepharose 4B. The molecular weight was estimated to be about 80, 000 by gel filtration, and the optimum pH was found to be 4.5. The enzyme was relatively stable in the pH range of 4-8 and up to 45°C on 10min incubation. The Km value for p-nitrophenyl α-L-fucoside was 0.87mM. The enzyme showed a novel substrate specificity in that it could hydrolyze porcine mucin and blood group substances of human saliva besides nitrophenyl compounds. Such a specificity has not been found for any other α-L-fucosidase from various sources.