type I and type II DHQases are quite distinct from one another in terms of amino acid sequences and three-dimensional structures. Type I enzymes involve a syn elimination and catalyse the biosynthetic reaction. By contrast type II enzymes, which can catalyse either the biosynthetic or catabolic reactions, involve and anti elimination reaction
DHQ2 catalyzes the reversible dehydration of 3-dehydroquinic acid to form 3-dehydroshikimic acid through anti elimination of water, with the loss of the more acidic pro-S hydrogen from C-2 of 3-dehydroquinate. The elimination proceeds by a stepwise E1CB mechanism involving an enol intermediate. In the first step, an essential tyrosine in the active site removes the pro-S hydrogen from C-2 of 1. The final step is the acid-catalyzed elimination of the C-1 hydroxy group, a reaction catalyzed by a histidine, which acts as a proton donor, reaction mechanism, overview
DHQ2 catalyzes the reversible dehydration of 3-dehydroquinic acid to form 3-dehydroshikimic acid through anti elimination of water, with the loss of the more acidic pro-S hydrogen from C-2 of 3-dehydroquinate. The elimination proceeds by a stepwise E1CB mechanism involving an enol intermediate. In the first step, an essential tyrosine in the active site removes the pro-S hydrogen from C-2 of 1. The final step is the acid-catalyzed elimination of the C-1 hydroxy group, a reaction catalyzed by a histidine, which acts as a proton donor, reaction mechanism, overview
DHQ2 catalyzes the reversible dehydration of 3-dehydroquinic acid to form 3-dehydroshikimic acid through anti elimination of water, with the loss of the more acidic pro-S hydrogen from C-2 of 3-dehydroquinate. The elimination proceeds by a stepwise E1CB mechanism involving an enol intermediate. In the first step, an essential tyrosine in the active site removes the pro-S hydrogen from C-2 of 1. The final step is the acid-catalyzed elimination of the C-1 hydroxy group, a reaction catalyzed by a histidine, which acts as a proton donor, reaction mechanism, overview