Deoxythymidine-5-triphosphate-d15 (dTTP-d15) dilithium is the deuterium labeled Deoxythymidine-5-triphosphate (HY-138615). Deoxythymidine-5-triphosphate (dTTP) is one of the four nucleoside triphosphates. Deoxythymidine-5-triphosphate (dTTP) is used in the synthesis of DNA[1].