Arylsulphatase clay interactions. I. Adsorption of arylsulphatase by kaolinite and montmorillonite

Abstract

The extent of arylsulphatase adsorption by both montmorillonite and kaolinite was determined using 0.1-1.0 µm fraction of sodium-clay freed from organic material, and a commercially purified arylsulphatase. Kaolinite-arylsulphatase affinity decreased with increasing solution enzyme concentration, but montmorillonitearylsulphatase affinity increased up to a solution enzyme concentration of approximately 15 mg/100 mg of clay, and decreased at higher enzyme concentrations. X-ray diffraction of the montmorillonite-arylsulphatase complex provided evidence of intercalation of the enzyme in the 2:1 lattice structure, as well as destruction of secondary and tertiary structures of the enzyme following adsorption on the interlattice surfaces.