Purification of Chorismate, Prephenate, and Arogenate by HPLC

Chorismic acid, a key branch-point intermediate in the shikimic acid pathway was first isolated and identified by Gibson and Gibson. j,2 The exact chemical structure was soon confirmed by Edwards and Jackman. 3 The importance of this compound in aromatic metabolism was illustrated by the eventual demonstration that at least five biochemical pathways utilize it as a precursor. 4,5 The flexibility of chorismate as a precursor in aromatic biosynthesis undoubtedly arises from its ability to undergo many spontaneous chemical rearrangements. 5 For example, the intramolecular Claisen (oxy-Cope)rearrangement, which yields prephenic acid, and the leaving of the enolpyruvyl group to produce p-hydroxybenzoic acid, have low activation energies and occur readily at temperatures commonly used for the preparation and storage of biochemical compounds. As a result, chorismate prepared by established procedures, 3.6-8 is usually contaminated with significant amounts of degradation compounds.