Figure 1

Schematic representation of the shikimic acid pathway. The first step is an aldol condensation between phosphoenol pyruvate [1] and erythrose-4-phosphate [2] catalyzed by 3-deoxy-D-arabinoheptulosonate-7-phosphate synthase (DAHP, or aroG/F/H according to E. coli nomenclature, EC 4.1.2.15) to synthesize 3-deoxy-D-arabino-heptulosonate-7-phosphate [3]. The second step is carried out by 3-dehydroquinate synthase (DHQ synthase, aroB, EC 4.6.1.3), affording 3-dehydroquinate [4]. The third step synthesizes 3-dehydroshikimate [5] catalyzed by 3-dehydroquinate dehydratase (DH-quinase, aroD, EC 4.2.1.10). Step 4 is catalyzed by shikimate dehydrogenase (Shikimate_DH, aroE, EC 1.1.1.25) to synthesize shikimate [6]. Steps 5 and 6 are catalyzed by shikimate kinase (SKI, aroK, EC 2.7.1.71) and 5-enolpyruvylshikimate-3-phosphate synthase (EPSP, aroA, EC 2.5.1.19) to give shikimate-3-phosphate [7] and 5-enolpyruvylshikimate-3-phosphate [8], respectively. The last reaction, catalyzed by chorismate synthase (aroC, EC 4.6.1.4) affords the final product of the pathway, chorismate [9].