Roles of chorismate mutase, isochorismate synthase and anthranilate synthase in plants

Chorismate is the substrate for a number of enzymes involved in the biosynthesis of aromatic compounds, making it a key branching point for secondary metabolites of the shikimate pathway. The enzymology and roles of three of the chorismate utilizing enzymes: chorismate mutase (EC 5.4.99.5), anthranilate synthase (EC 4.1.3.27) and isochorismate synthase (EC 5.4.99.6) are reviewed and discussed with emphasis of their importance for secondary metabolism. In particular the possible presence and localization of two isoenzymes, a regulated plastidic form and a non-regulated cytosolic form are discussed.