IMMOBILIZATION OF INVERTASE ON POROUS MEMBRANES MADE FROM MODIFIED POLYSULFONE

The activity of invertase that was immobilized within asymmetric ultra filtration membranes was determined as a function of the immobilizatio n mode such as adsorption, ionic interaction and covalent bonding. For these different bonding possibilities adequate membranes were prepare d from chemically modified polysulfone fitted out with the correspondi ng substituents. The amount of enzyme was lowest for adsorption and hi ghest for chemical fixation. In the latter case spacers were useful be cause substituents adjacent to the polymer backbone caused a relativel y large loss of activity which car, stem either from chemical reaction or from the hampered development of the appropriate conformational st ructure. Compared to the activity of the native invertase the fixation yielded a remarkable reduction of activity which was compensated for by the very extended stability of the bonded enzyme.