Raltitrexed is an anti-tumor drug for advanced colorectal cancer. Raltitrexed is a highly selective inhibitor of thymidylate synthase (TS), the key enzyme in the biochemical conversion of dUMP to dTMP. It enters the cell via the reduced folatefmethotrexate cell membrane carrier and is converted to the polyglutamate species by folylpolyglutamate synthase within 4h where it then binds to the folate substrate site of TS.
