Michael additions in polyketide biosynthesis.

Covering: up to July 2018 Polyketides constitute a large family of natural products exhibiting various biological activities. Polyketide biosynthetic systems employ several strategies for the production of structurally diverse polyketides. Among the polyketide biosynthetic enzymes, a growing number of enzymes that catalyze a Michael-type addition have been identified. These enzymes are responsible for constructing unique polyketide backbone structures, forming heterocycles, and incorporating heteroatoms into the polyketide backbone, all of which contribute to the diversification of the polyketide structure. This review summarizes the current understanding of the function of enzymes catalyzing a Michael-type addition in polyketide biosynthesis, with a particular focus on mechanistic studies.