Involved in the third step of the chorismate pathway, which leads to the biosynthesis of aromatic amino acids. Catalyzes the cis-dehydration of 3-dehydroquinate (DHQ) and introduces the first double bond of the aromatic ring to yield 3-dehydroshikimate. The reaction involves the formation of an imine intermediate between the keto group of 3-dehydroquinate and the epsylon-amino group of Lys-170 at the active site. 3-dehydroquinase Protein, Salmonella typhi, Recombinant (His) is expressed in yeast with N-6xHis tag. The predicted molecular weight is 29.6 kDa and the accession number is P24670.