3-dehydroquinate dehydratase catalyses the third step in the biosynthesis of chorismate within the Shikimate pathway which synthesises aromatic compounds as well as in the degradative quinate pathway. It is a type I dehydroquinase which catalyses a cis-dehydration of the hexane ring of 3-dehydroquinate via a covalent imine intermediate (unlike the type II dehydroquinase which catalyses a trans-dehydration via an enolate intermediate). Type I dehydroquinases use a Schiff base mechanism. The pathway is essential in microorganisms and plants for the biosynthesis of compounds such as folate, ubiquinone and aromatic amino acids. The absence of this pathway in animals makes it an attractive target for antimicrobial agents.