Irreversible immobilization of diisopropylfluorophosphatase in polyurethane polymers

The synthesis of polyurethane polymers in the presence of diisopropylfluoro phosphatase (DFPase) has enabled the irreversible attachment of the enzyme to the polymeric matrix. The resulting bioplastic hydrolyzes diisopropylflu orophosphate (DFP) in buffered media up to 67% of the rate for the same amo unt of soluble enzyme. Above a DFPase concentration of approximately 0.1 mg /g(foam) the rate of the reaction catalyzed by the enzyme-containing polyme r was controlled by internal mass transfer. Increasing foam hydrophilicity, via the use of nonionic surfactants during polymerization, significantly a ffected the structural properties of matrix, thereby enhancing the intrinsi c and apparent efficiency of modified DFPase. The resulting reduction in in ternal mass transfer limitations was explained morphologically with electro n microscopy.