Purification of α- l-fucosidase of abalone livers

Abstract

Purification of the α-fucosidase of abalone livers was attempted by fractionation with ammonium sulfate and subsequent treatments with DEAE-cellulose and IRC-50 resin. The estimations of recovery and purity of the enzyme were followed using p-nitrophenyl α- l-fucoside as substrate. The preparations obtained after treatments with DEAE-cellulose columns or IRC-50 resin were almost free of β- l-fucosidase, although they were contaminated with relatively large amounts of N-acetyl-β-glucosaminidase and N-acetyl-β-galactosa minidase. Both preparations were shown to contain two types of α- l-fucosidase different in the dependence of activity on pH and in substrate specificity. One was optimally active at around pH 5 on p-nitrophenyl α- l-fuicoside but not on the fucosidic linkages of porcine submaxillary mucin, while the other was optimally active around pH 2 on the synthetic substrate as well as on porcine submaxillary mucin. Evidence was obtained to show that the crude enzyme of the acetone-ether dry powder of the tissue homogenate used for the starting material contains a specific inhibitor for the enzyme component showing the highest activity at pH 2.