Arogenate (pretyrosine) pathway of tyrosine and phenylalanine biosynthesis in Pseudomonas aureofaciens ATCC 15926.

Abstract

Assays of enzyme activities suggest that arogenate, the product of prephenate transamination, is an intermediate in the biosynthesis of both phenylalanine and tyrosine in Pseudomonas aureofaciens ATCC 15926. In addition to prephenate dehydratase and prephenate dehydrogenase, arogenate dehydratase and arogenate dehydrogenase activities were demonstrated. This pattern of aromatic amino acid biosynthesis in pseudomonads had previously been demonstrated only in P. aeruginosa. Arogenate dehydrogenase from P. aureofaciens differs from that in P. aeruginosa in its utilization of either NAD+ or NADP+ as cofactor and its inhibition by L-tyrosine. During ammonium sulphate fractionation, arogenate dehydratase co-precipitated with prephenate dehydratase I activity and not with prephenate dehydratase II. The pattern of regulation of the arogenate route to tyrosine in P. aureofaciens ATCC 15926 differed from that previously reported for strain ATCC 13986.