Isobavachalcone in the regulation of dihydroorotate dehydrogenase in pyrimidine biosynthesis and myeloid blast differentiation. Left, the pyrimidine biosynthesis pathway and its biological functions. Isobavachalcone (IBC) prevents DHODH from catalyzing dihydroorotate into orotate, blocking pyrimidine biosynthesis, resulting in myeloid lineage differentiation and induction of apoptosis. The role of DHODH and the negative impact of c-MYC on myeloid blast differentiation is indicated by the dotted line/arrow. DHODH: dihydroorotate dehydrogenase; UMP: uridine 5′-monophosphate; UTP: uridine triphosphate; CTP: cytidine triphosphate; dTTP: deoxythymidine triphosphate; UDP-GlcNAc: uridine diphosphate N-acetylglucosamine; CDP-DAG: cytidine diphosphate diacylglycerol; CDP-choline: cytidine diphosphate choline; O-GlcNAc: O-linked N-acetylglucosamine; OGT: O-GlcNAc transferase. CTP to dTTP requires multiple steps.