A KINETIC AND STRUCTURAL COMPARISON OF CHORISMATE MUTASE-PREPHENATE DEHYDRATASE FROM MUTANT STRAINS OF ESCHERICHIA-COLI-K12 DEFECTIVE IN THE PHEA GENE

Abstract

Three classes of mutant strains of Escherichia coli K12 defective in pheA, the gene coding for chorismate mutase/prephenate dehydratase, have been isolated: (1) those lacking prephenate dehydratase activity, (2) those lacking chorismate mutase activity, and (3) those lacking both activities. Chorismate mutase/prephenate dehydratase from the second class of mutants was less sensitive to inhibition by phenylalanine than wild-type enzyme and, along with the defective enzyme from the third class of mutants, could not be purified by affinity chromatography on Sepharosyl-phenylalanine. Pure chorismate mutase/prephenate dehydratase protein was prepared from two strains belonging to the first class...