Chorismic acid is a metabolic intermediate that is the branch point in the synthesis of coenzyme Q and the aromatic amino acids, phenylalanine, tyrosine, and tryptophan (Figure 21.12).

Chorismate is formed from 5-enoylpyruvylshikimic acid 3-phosphate (Figure 21.13). Conversion of chorismate to p-hydroxybenzoic acid leads to synthesis of coenzyme Q. Conversion of chorismate to anthranilate leads to biosynthesis of tryptophan (Figure 21.14).