A new combined enzyme-charcoal system adsorption on charcoal followed by polymer coating.

A method is described for a new combined enzyme-charcoal system. A model enzyme, urease, was adsorbed on activated charcoal granules which was then coated with ultrathin cellulose nitrate. The assayed activity of this immobilized enzyme was 28.1% /+- 3.12% (mean /+- S.D.) of the activity of urease in solution. The enzyme did not leak out after immobilization and worked efficiently. The assayed urease activity increased with greater amounts of urease/gm immobilized enzyme, but reached a plateau after 40 sumner units/gm. Immobilized urease has good storage and operational stabilities at refrigerator, room and body temperatures. In-vivo studies show that about 90% conversion urea in one single pass is possible.