Deoxythymidine-5'-triphosphate - 15 N 2 (dTTP- 15 N 2 ) dilithium is 15 N labeled Deoxythymidine-5'-triphosphate. Deoxythymidine-5'-triphosphate (dTTP) is one of the four nucleoside triphosphates. Deoxythymidine-5'-triphosphate (dTTP)is used in the synthesis of DNA.