Enzymatic synthesis of D-sorbose and D-psicose with aldolase RhaD: Effect of acceptor configuration on enzyme stereoselectivity

It was previously reported that DHAP-dependent aldolase RhaD selectively chooses L-glyceraldehyde from racemic glyceraldehyde to produce L-fructose exclusively. Contrastingly, we discovered that D-glyceraldehyde is also tolerated as an acceptor and the stereoselectivity of the enzyme is lost in the corresponding aldol addition. Furthermore, we applied this property to efficiently synthesize two rare sugars D-sorbose and D-psicose. (C) 2011 Elsevier Ltd. All rights reserved.