Three genes related to the biosynthesis of phenylalanine, pheA,aroG, and tyrB , encode key enzymes: a bifunctional protein\|chorismate mutase (CM)/prephenate dehydratase (PD).3\|deoxy\|D\|arabino\|heptulonate\|7\|phosphate synthetase (DS), and aminotransferase (AT),respectively.In this work,these genes were amplified from Escherichia coli mutants resistant to fluro\|L\|phenylalanine (FP) by polymerase chain reaction (PCR).The genes were expressed either separately or linked tandem as operons in th...