Thymidylate synthase (TS) is a key enzyme in the synthesis of 2'-deoxythymidine-5'-monophosphate, an essential precursor for DNA biosynthesis. Thymine nucleotide synthase is a key enzyme in the de novo synthesis pathway of mitochondrial thymine. For this reason, it is a key target for cancer chemotherapy, and considered to be the main target of 5-fluorouric acid, 5-fluoro-2'-deoxyribonucleic acid and some folate compounds.
