Phenylalanine dehydrogenase mutants: Efficient biocatalysts for synthesis of non-natural phenylalanine derivatives

Wild-type phenylalanine dehydrogenase from Bacillus sphaericus, and three mutants N145A, N145V and N145L, are used with a coenzyme recycling system to synthesise l-phenylalanine and three non-natural amino acids (p-F-phenylalanine, p-MeO-phenylalanine and p-CF3-phenylalanine) on a millimole scale. A range of reaction conditions are investigated. The kinetic parameters of WT PheDH and N145A towards p-CF3-phenylpyruvate are compared, emphasising the value of protein engineering in creating improved biocatalysts.