Purification and properties of two forms of α-l-fucosidase from Turbo cornutus

1. 1. Two forms of α- l -fucosidase were isolated from the gastropod, Turbo cornutus and their properties studied. 2. 2. Fucosidase I (pI 6.78) and Fucosidase II (pI 5.5) were purified by a scheme which included Sephadex G-200 column chromatography, DEAE-Sephadex column chromatography, heat treatment, CM-cellulose column chromatography and preparative isoelectric focusing. 3. 3. The purified forms were substantially free of all other glycosidase contaminations and had specific activity approximately 73 and 65 fold of the starting material. 4. 4. The pH activity profile of Fucosidase I displayed a pH optimum at 4.0, and that of Fucosidase II showed a broad optimum centered at pH 3.6. 5. 5. Fucosidase I was thermolabile and lost greater than 90% of its activity when incubated at 55°C for 15 min. Fucosidase II was thermostable, and lost less than 30% of its initial activity under identical incubation conditions. 6. 6. Both enzymes had an apparent molecular weight of 230,000 ± 20,000 and were inhibited by Hg2+, l -fucose and l -galactose. 7. 7. The Km values of Fucosidase I and II for the substrate p- nitrophenyl-α- l -fucopyranoside were 0.38 and 0.14 mM, respectively.