this invention provides a method for the maintenance of continuous activity of an immobilized enzyme reaction by initially underloading an adsorbent with a desired enzyme , monitoring the activity of the enzyme and periodically adding fresh enzyme to maintain a constant , continuous level of activity until the maximum carrying capacity of the support is reached . the method is preferably carried out when continuously isomerizing glucose to fructose with glucose isomerase adsorbed to a weakly basic anion exchange resin .