Drug delivery studies in Caco-2 monolayers. VI. Studies of enzyme substitution therapy for phenylketonuria - a new application of Caco-2 monolayers

Phenylalanine ammonia-lyase (PAL) which is an enzyme capable of converting L-phenylalanine to trans-cinnamic acid has been shown to be able to minimize the amount of L-phenylalanine transported across Caco-2 monolayers when administered apically. The impact of this is that a formulation of PAL, able to lower the transport of L-phenylalanine across epithelia, potentially could be applied in the oral treatment of phenylketonuria. Confluent monolayers of Caco-2 cells were shown to simplify the studying of the simultaneous events of conversion and transport across an epithelial barrier. (C) 1998 Elsevier Science B.V.