malonyl-coenzyme-a and isoliquiritigenin

Recombinant chalcone synthase (CHS) from Scutellaria baicalensis accepted cinnamoyl diketide-NAC and cinnamoyl-NAC as a substrate, and carried out sequential condensations with malonyl-CoA to produce 2',4',6'-trihydroxychalcone. Steady-state kinetic analysis revealed that the CHS accepted the diketide-NAC with less efficiency, while cinnamoyl-NAC primed the enzyme reaction almost as efficiently as cinnamoyl-CoA. On the other hand, it was for the first time demonstrated that the diketide-NAC was also a substrate for recombinant polyketide reductase (PKR) from Glycyrrhiza echinata, and converted to the corresponding beta-ketohemithioester. Furthermore, by co-action of the CHS and the PKR, the NAC-thioesters were converted to 6'-deoxychalcone in the presence of NADPH and malonyl-CoA.

Topics: Acyl Coenzyme A; Acyltransferases; Alcohol Oxidoreductases; Bacterial Proteins; Carbon Radioisotopes; Catalysis; Chalcone; Chalcones; Chromatography, High Pressure Liquid; Chromatography, Thin Layer; Cysteamine; Esters; Glycyrrhiza; Kinetics; Malonyl Coenzyme A; Molecular Structure; Oxidation-Reduction; Recombinant Proteins; Sulfhydryl Compounds