Immobilization of β-Galactosidase on an Insoluble Carrier with a Polyisocyanate Polymer. I. Preparation and Properties

Abstract

Active fl-galaetosidase was immobilized on a polyisocyanate polymer previously applied to Teflon stirring bars. Maximum enzyme activity was attained by immobilizing the enzyme in phosphate buffer at pH 5.0. Although more fi-galactosidase was immobilized at lower pH values, percentage of soluble specific activity remained nearly constant (about 19%) at pH values ranging from 5.0 to 8.5. The immobilized enzyme was stable for prolonged periods, and soluble enzymic activity was absent. Manganese or magnesium ions activated both soluble and immobilized fl-galactosidase, but the percent activation was less for the immobilized enzyme, possibly due to hindered conformational changes.