[The effect of glycolipids [correction of glycoproteins] on the oligomeric structure and catalytic activity of alpha-L-fucosidase from human kidneys].

alpha-L-Fucosidase (EC 3.2.1.51) has been isolated from human kidney and purified to homogeneity by affinity chromatography on concanavalin A-Sepharose and fucosylamino-Sepharose. The catalytic activity and oligomeric structure of the enzyme were studied in a reversed micelle system of aerosol OT in octane. Depending on the degree of hydration (a parameter determining the geometrical sizes of the inner aqueous cavity of micelles), fucosidase is present within micelles as 53 kDa monomers, 110 kDa dimers, 230 kDa tetramers and 480 kDa octamers. Association of the monomers into tetra- or octamers causes a 3-4 fold increase in the specific catalytic activity of alpha-L-fucosidase. At pH and ionic strength values corresponding to intralysosomal ones alpha-L-fucosidase is isolated from tissues exclusively in a tetrameric form. After treatment with sodium cholate and subsequent dialysis this tetramer irreversibly dissociates into monomers; this reaction is accompanied by 2-3-fold decreases in the specific catalytic activity of alpha-L-fucosidase. The enzyme tetrameric structure and specific catalytic activity may be reconstituted in a reversed micelle system in the presence of glycolipids-di- and trihexosylceramides, GM1-ganglioside and a mixture of bovine brain gangliosides.