Isolation of a novel NADPH‐dependent reductase which coacts with chalcone synthase in the biosynthesis of 6′‐deoxychalcone

Enzyme synthesis of 6′‐deoxychalcone from 4‐coumaroyl‐CoA and malonyl‐CoA has been achieved, using purified soybean chalcone synthase (CHS), NADPH and a further protein (reductase). This reductase was purified to apparent homogeneity by a procedure including affinity chromatography on Blue Sepharose and elution with NADP+. This enzyme has a molecular mass of about 34 kDa and consists of a single polypeptide. Synthesis of deoxychalcone also occurred with parsley CHS, NADPH and the soybean reductase. The reductase catalyzed transfer of the pro‐R hydrogen of [4‐3H]NADPH to the substrate.