Type I 3-dehydroquinase, (3-dehydroquinate dehydratase or DHQase.) Catalyses the cis-dehydration of 3-dehydroquinate via a covalent imine intermediate giving dehydroshikimate. Dehydroquinase functions in the shikimate pathway which is involved in the biosynthesis of aromatic amino acids. Type II 3-dehydroquinase catalyses the trans-dehydration of 3-dehydroshikimate see Pfam:PF01220.

1: The two types of 3-dehydroquinase have distinct structures but catalyze the same overall reaction. Gourley DG, Shrive AK, Polikarpov I, Krell T, Coggins JR, Hawkins AR, Isaacs NW, Sawyer L; Nat Struct Biol 1999;6:521-525. PMID:10360352

2: The molecular biology of multidomain proteins. Selected examples. Hawkins AR, Lamb HK; Eur J Biochem 1995;232:7-18. PMID:7556173