ABSTRACT
The development of methods for the stereoselective formation of carbon-carbon bonds using the aldol reaction is a current topic of interest in organic synthesis. Three general types of enzymes have been applied for the formation of carbon-carbon bonds in organic synthesis: aldolases, synthetases, and transketolases. d-Fructose-1,6-diphosphate aldolase from rabbit muscle catalyzes the equilibrium condensation of dihydroxyacetone phosphate with d-glyceraldehyde-3-phosphate to form dfructose-1, 6-biphosphate. Transketolase catalyzes the reversible transfer of the hydroxyketo group of a ketose phosphate to an aldose phosphate. In addition to its acceptance of unnatural substrates, several other characteristics make NeuAc aldolase a useful catalyst in synthesis. The cloning of the enzyme has reduced its cost and offers the potential to produce large quantities of proteins with improved stability or with altered stereoselectivity. Reactions catalyzed by NeuAc aldolase have produced several grams of NeuAc after purification by ion-exchange chromatography.
