MCS catalyzes the formation of malonyl-CoA in a two-step reaction consisting of the adenylation of malonate with ATP, followed by malonyl transfer from malonyl-AMP to CoA. Malonic acid and its derivatives are the building blocks of polyketides and malonyl-CoA serves as the substrate of polyketide synthases. Malonyl-CoA synthetase has broad substrate tolerance and can activate a variety of malonyl acid derivatives. MCS may play an important role in biosynthesis of polyketides, the important secondary metabolites with therapeutic and agrochemical utility.