A simple spectrophotometric assay for arogenate dehydratase

A simple spectrophotometric assay for arogenate dehydratase, the enzyme that catalyzes the formation of L-phenylalanine from L-arogenate, is presented. The method couples the arogenate dehydratase reaction with that of an aromatic aminotransferase partially purified from Acinetobacter calcoaceticus. In the presence of 2-ketoglutarate, phenylpyruvate formation is measured at 320 nm at basic pH. The method was compared with two other methods already in use in our laboratory for arogenate dehydratase. The new method is simple, quick, fairly sensitive, and especially suitable for the screening of a large number of samples.