Delineating Monascus azaphilone pigment biosynthesis: oxidoreductive modifications determine the ring cyclization pattern in azaphilone biosynthesis

The product profiles of mppF, mppA, and mppC mutants substantiate that MppA-mediated omega-2 ketoreduction is a prerequisite for the synthesis of the pyranoquinone bicyclic core of the Monascus azaphilone pigment and that MppC activity determines the regioselectivity of the spontaneous Knoevenagel condensation.