Phenylalanine ammonia‐lyase immobilized in semipermeable microcapsules for enzyme replacement in phenylketonuria

Abstract

Phenylalanine ammonia-lyase immobilized within semipermeable microcapsules has an assayed enzyme activity which is 20% ± 4% of the enzyme in free solution. The K_m for the immobilized enzyme remained the same as that of the free enzyme. The pH optimum also remained unchanged at pH 8.5 ± 1.0. At the lower pH range, enzyme activity is higher for the immobilized enzyme. Daily oral administration of microencapsulated phenylalanine ammonia-lyase to phenylketonuric rats decreased the systemic phenylalanine level by 35 ± 8% in 2 days (P < 0.05) and by 75 ± 8% in 7 days (P < 0.001).