Abstract

Aldehyde reductase, member of the aldo-keto reductase superfamily, catalyzes the reduction of a variety of aldehydes and ketones to their corresponding alcohols. Hexagonal crystals of porcine aldehyde reductase in complex with NADPH and the flavonoid inhibitor quercetin have been grown using the hanging-drop vapour­ diffusion method with ammonium sulfate as precipitant. The binding of quercetin into the active site of aldehyde reductase was revealed from a difference electron density map. This is the first crystallization report of an aldo-keto reductase in complex with a flavonoid.