In enzymology, an acridone synthase () is an enzyme that catalyzes the chemical reaction 3 malonyl-CoA + N-methylanthraniloyl-CoA 4 CoA + 1,3-dihydroxy-N-methylacridone + 3 CO2 Thus, the two substrates of this enzyme are malonyl-CoA and N-methylanthraniloyl-CoA, whereas its 3 products are CoA, 1,3-dihydroxy-N-methylacridone, and CO2. This enzyme belongs to the family of transferases, specifically those acyltransferases transferring groups other than aminoacyl groups. The systematic name of this enzyme class is malonyl-CoA:N-methylanthraniloyl-CoA malonyltransferase (cyclizing). This enzyme participates in acridone alkaloid biosynthesis. References EC 2.3.1 Enzymes of unknown structure