Purification and some properties of a β-xylosidase and an α-fucosidase from apple snails (pomacea canaliculata)

Abstract

β-Xylosidase and α-fucosidase were purified from the viscera of apple snails (Pomacea canaliculata) using ammonium sulfate precipitation, hydrophobic chromatography on Butyl-Toyopearl, gel filtration on Sephacryl S-300, and Q-Sepharose column chromatography. 69:85403B2;-Xylosidase and α-fucosidase are glycoproteins and their molecular masses were estimated to be approximately 85 kDa and 54 kDa by SDS-polvacrylamide gel electrophoresis, and assumed to be about 96 kDa and 230 kDa from their sedimentation coefficients, respectively, indicating that the former is a monomer and the latter has a tetrameric structure. β-Xylosidase is stable at pH 4–10 and its optimum pH toward pNP-β-D-xyloside is around 3.6, while α-fucosidase is fairly stable at 65°C and pH 4–10, and its optimum pHs toward pNP-α-L-fucoside are around 3.2 and 5.2. β-Xylosidase released a xylose residue from Xylβ1 → 2Manβ1 → 4GlcNAcβ1 → 4(Fucα1 → 3)GlcNAc-PA and Manα1 → 6(Manα1 → 3)(Xylβ1 → 2)Manβ1 → 4GlcNAcβl → 4(Fucαl → 3)GlcNAc-PA, but not from GlcNAcβl → 2Manα1 → 6(GlcNAcβ1 → 2Manα1 → 3)(Xylβ1 → 2)Manβ1 → 4GlcNAcβ1 → 4(Fucα1 → 3)GlcNAc-PA, while α-fucosidase released a fucose residue from these three PA-oligosaccharides. © 1996, Taylor & Francis Group, LLC. All rights reserved.